WARD JOHN TRINWITH (AU)
| EP0296570A1 | 1988-12-28 | |||
| EP1826171A2 | 2007-08-29 | |||
| US4745853A | 1988-05-24 | |||
| US5124088A | 1992-06-23 | |||
| GB2013096A | 1979-08-08 | |||
| US6245127B1 | 2001-06-12 |
| - 145 -
CLAIMS
1. A method for producing carbonated water, the method comprising the steps of: manufacturing a gas containing carbon dioxide on site; and in situ mixing the carbon dioxide with water to produce carbonated water.
2. A method as claimed in claim 1, wherein the step of manufacturing the gas containing carbon dioxide comprises conducting a combustion reaction to produce carbon dioxide.
3. A method as claimed in either claim 1 or 2, wherein the method further comprises the step of purifying the gas containing carbon dioxide .
4. A method as claimed in claim 3, wherein the step of purification occurs by swing sorption.
5. A method as claimed in either claims 3 or 4, wherein the step of purification comprises combined thermal and pressure swing sorption.
6. A method as claimed in any one of claims 3 to 5, wherein the method also comprises the step of pressurising the purified carbon dioxide.
7. A method as claimed in any one of the preceding claims, wherein the method also comprises the step of pressurising the water which the purified carbon dioxide is mixed with.
8. A method as claimed in any one of the preceding claims, wherein the method also comprises the step of storing the carbonated water produced in a pressurised
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vessel .
9. A method as claimed in any one of the preceding claims, wherein the step of manufacturing the gas containing carbon dioxide comprises combusting natural gas.
10. A method as claimed in claim 9, wherein combusting the natural gas occurs in approximately 20% by volume excess air.
11. A method as claimed in any one of claims 2, 9 or 10, wherein the method also comprises the step of cooling the gas containing carbon dioxide produced by the combustion reaction.
12. A method as claimed in any one of the preceding claims, wherein the method also comprises the step of obtaining water from a water supply for mixing with the carbon dioxide.
13. A method as claimed in claim 12, wherein the method further comprises the step of buffering the water supply from any carbon dioxide or pressurised water.
14. A method as claimed in claim 13, wherein the step of buffering the reticulated mains water supply comprises supplying water to a cool water reservoir from which water can be drawn to use in the step of mixing the carbon dioxide with water.
15. A method as claimed in any one of claims 4 to 6, wherein the step of purification of the gas containing carbon dioxide by swing sorption comprises the steps of sorption of the carbon dioxide on a regenerable sorbent in a sorber/desorber followed by desorption of the carbon dioxide from the sorbent .
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16. A method as claimed in any one of claims 4-6 or 15, wherein the step of purification by swing sorption also comprises the step of pressure release by letting down the pressure in the sorber/desorber to atmospheric pressure.
17. A method as claimed in any one of claims 4-6, 15 or 16, wherein the step of purification of carbon dioxide by swing sorption also comprises the step of vacuum purging the sorber/desorber of extraneous gases by application of a vacuum on the sorber/desorber.
18. A method as claimed in any one of claims 4-6, 15- 17, wherein the step of sorption of the carbon dioxide comprises compressing the gas containing carbon dioxide into a sorber/desorber using a compressor.
19. A method as claimed in claim 18, wherein the compressor for the step of sorption of the carbon dioxide is a liquid ring compressor.
20. A method as claimed in claim 19, wherein the method also comprises the step of using the water from the combustion reaction as the liquid in the liquid ring compressor.
21. A method as claimed in claim 17, wherein the method also comprises the step of recovering carbon dioxide from the vacuum purged gases by dissolution of the carbon dioxide in water.
22. A method as claimed in claim 17, wherein the method also comprises the step of recovering carbon dioxide from the vacuum purged gases by directing the purged gases through a second sorber/desorber.
23. A method as claimed in any one claims 4-6, 15-22,
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wherein the step of desorption comprises applying pressure below atmosphere to the sorber/desorber using a compressor.
24. A method as claimed in claim 23, wherein the compressor is a liquid ring compressor.
25. A method as claimed in any one of the preceding claims, wherein the method further comprises the step of venting gases to remove and act against the build up of extraneous gases .
26. A method as claimed in claim 25, wherein the step of venting comprises the enriching the gases to be vented in extraneous gases in the vapour space of a vessel by contacting the desorbed gases in the vessel with water at least once.
27. A method as claimed in any one of claims 4-6, 15- 24, wherein method also comprises the step of mitigating against any backflow of mains water into the sorber/desorber .
28. A method as claimed in any one of claims 4-6, 15- 24 or 27, wherein the method comprises using the compressor, which compresses gas into the sorber/desorber, to act as a fluid displacement pump to pressurise the water which is mixed with the carbon dioxide to produce carbonated water.
29. A plant for producing carbonated water, the plant comprising an apparatus for manufacturing a gas containing carbon dioxide and a mixer for mixing the carbon dioxide with water to produce carbonated water.
30. A plant as claimed in claim 29, wherein the plant also comprises at least one primary compressor for
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compressing the gas containing carbon dioxide and at least one secondary compressor for pressurising the water which are mixed to produce carbonated water.
31. A plant as claimed in claim 30, wherein at least one of the primary compressors and at least one of the secondary compressors may be a single liquid ring compressor.
32. A plant as claimed in any one claims 29-31, wherein the plant also comprises a purifier for purifying the gas containing carbon dioxide.
33. A plant as claimed in claim 32, wherein the purifier comprises a sorber/desorber for purifying the gas containing carbon dioxide by swing sorption.
34. A plant as claimed in claim 33, wherein, the plant comprises at least one tertiary compressor for compressing the gas containing carbon dioxide into the sorber/desorber .
35. A plant as claimed in claim 34, wherein the tertiary compressor (s) is a liquid ring compressor (s) .
36. A plant as claimed in either claim 33 or 34 when dependent on claim 30, wherein at least one of the primary compressors and at least one of the tertiary compressors are a single liquid ring compressor.
37. A plant as claimed in any one of claims 33-36, wherein the purifier comprises a second sorber/desorber for recovery of carbon dioxide from the vacuum purged gases of the sorber/desorber.
38. A plant as claimed in any one of claims 33-37, wherein the plant also comprises at least one primary
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pump for pumping water for cooling and/or heating through heat exchanger tubes of the sorber/desorber .
39. λ plant as claimed in claim 38 when dependent on claim 30, wherein any secondary compressor may also provide the function of the primary pump.
40. A plant as claimed in claim 38 when dependent on claim 31, wherein the primary and secondary compressor as a single liquid ring compressor may also provide the function of the primary pump.
41. A plant as claimed in claim 38 when dependent on claim 36, wherein the primary and tertiary compressor as a single liquid ring compressor may also provide the function of the primary pump.
42. A plant as claimed in any one of claims 33-41, wherein the sorber/desorber contains a sorbent upon which carbon dioxide is preferentially sorbed.
43. A plant as claimed in claim 42, wherein the sorbent comprises the salts of an alkali metal or a metal oxide .
44. A plant as claimed in either claim 42 or 43, wherein the sorbent has a polystyrene, silica gel, polyether, acrylic or carbon molecular sieve backbone and amine functionality
45. A plant as claimed in any one of claims 42-44, wherein the sorbent is a weak base anion exchange resin, with tertiary amine functionality.
46. A plant as claimed in any one of claims 42-45, wherein the sorbent is a solid sorbent which is essentially immiscible with water.
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47. A plant as claimed in any one of claims 29-46, wherein the plant is supplied with water from a water supply and comprises a cool water reservoir for providing a buffer between the water supply and any carbon dioxide or pressurised water in the plant.
48. A plant as claimed in any one of claims 29-47, wherein the plant also comprises a product drawdown vessel for storing the carbonated water produced by the plant and for dispensing the carbonated water therefrom.
49. A plant as claimed in claim 48, wherein the product drawdown vessel has an automatic drain float valve for preventing the carbonated water from being dispensed from the product drawdown vessel when the carbonated water is at a low level in the vessel.
50. A plant as claimed in any one of claims 29-49, wherein the apparatus for manufacturing a gas containing carbon dioxide is a combustion unit for combusting a hydrocarbon in a combustion reaction.
51. A plant as claimed in claim 50, wherein the hydrocarbon is natural gas.
52. A plant as claimed in any one of claims 29-51, wherein the plant also comprises one or more venting vessels for venting gases from the vapour space thereof, so as to further remove and act against the build up of extraneous gases .
53. A plant as claimed in claim 52 when dependent upon claims 48 or 49, wherein one of the venting vessels may comprise the product drawdown vessel.
54. A plant as claimed in claims 48, 49 or 52,
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wherein the plant also comprises a PDV fill control mechanism for controlling filling of the product drawdown vessel .
55. A plant as claimed in claim 54, wherein the PDV fill control mechanism comprises a low level switch on the product drawdown vessel for activating filling of the product drawdown vessel with carbonated water upon detection of a design low liquid level and a low pressure switch on the product drawdown vessel for activating input of pressurised carbon dioxide gas to the product drawdown vessel upon detection of a design low pressure level.
56. A plant as claimed in any one of claims 33-46, wherein the plant also comprises a back flow mitigation system for mitigating against any backflow of mains water into the sorber/desorber .
57. A plant as claimed in one of claims 29-56, wherein the plant also comprises a valve system for directing the fluid flow during the operation of the plant at the different operation steps.
58. A plant as claimed in claim 57, wherein the valve system comprises a rotary pinch valve.
59. A plant as claimed in claim 58, wherein the rotary pinch valve is driven by the same motor that drives any one or more the pumps or compressors in the plant.
60. A plant as claimed in either claims 50 or 51, wherein the plant also comprises a water balance system for balancing the water produced in the combustion reaction by disposing of water from the plant.
61. A plant as claimed in claim 60, wherein the water balance system comprises an evaporator tray on which the
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disposed water may be evaporated.
62. A plant as claimed in any one of claims 29-61, integrated with a soft drink plant for producing and dispensing soft drinks using the produced carbonated water.
63. A plant as claimed in any one of claims 29-62, wherein the plant also comprises a vacuum fill vessel for introducing water to the plant.
64. A plant for producing and dispensing carbonated water, the plant comprising: a feed of a gas containing carbon dioxide; a feed of water; a mixer for mixing the feeds of gas containing carbon dioxide and water to produce the carbonated water; a vessel for receiving and storing the carbonated water; a dispenser which can be fluidly communicating with the vessel through which carbonated water is dispensed from the vessel; a chamber for accumulating gas from the gas-water mixture held in the vessel; and a venting system operable to enable venting of at least a portion of the gas accumulated in the chamber in association with dispensing of the carbonated water from the vessel and/or in association with filling of the vessel .
65. A plant as claimed in claim 64, wherein the vessel is also the mixer.
66. A plant as claimed in either claims 64 or 65, wherein the venting system is operable only in association with dispensing of the carbonated water from the vessel.
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67. A plant as claimed in either claims 64 or 65, wherein the venting system is operable only in association with filling of the vessel.
68. A plant as claimed in either claim 64 or 65, wherein the venting system is operable in association with both dispensing from and filling of the vessel.
69. A plant as claimed in any one of claims 64 to 66, wherein the venting system is operable to enable venting of at least a portion of the accumulated gas upon dispensing of the carbonated water from the vessel.
70. A plant as claimed in any one of claims 64 to 66, wherein the venting system is operable to enable venting of at least a portion of the accumulated gas immediately after dispensing from the vessel has been completed.
71. A plant as claimed in any one of claims 64, 65 or 68, wherein the venting system is operable to enable venting of at least a portion of the accumulated gas immediately after filling of the vessel is completed.
72. A plant as claimed in any one of claims 64, 65 or 68, wherein the venting system is operable to enable venting of at least a portion of the accumulated gas on commencement of filling.
73. A plant as claimed in any one of claims 64-66 and 69, wherein the venting system is operable to enable venting of at least a portion of the gas accumulated in the chamber by flowing the carbonated water being dispensed through the chamber.
74. A plant as claimed in any one of claims 64-66, 69 and 73, wherein the venting system is operable to enable the vented gas to flow in advance of the carbonated water
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being dispensed.
75. A plant as claimed in any one of claims 64-74, wherein the venting system is operable to enable venting of at least a portion of the gas accumulated in the chamber by opening the chamber to atmosphere.
76. A plant as claimed in any one of claims 64-75, wherein the venting system is operable to isolate the chamber from the vessel when venting at least a portion of the gas accumulated in the chamber.
77. A plant as claimed in any one of claims 64-69, 75 or 76, wherein the venting system is operable to vent accumulated gas in parallel with the dispenser
78. A plant as claimed in any one of claims 64-77, wherein the venting system comprises a restrictive device for restricting the flow of gas being vented from the chamber.
79. A plant as claimed in claim 78, wherein the restrictive device is an orifice or a pressure relief valve having cracking pressure less than the equilibrium pressure in the vessel.
80. A plant as claimed in any one of claims 64-79, wherein the venting system comprises a multiport valve.
81. A plant as claimed in any one of claims 64-80, wherein the feed of a gas containing carbon dioxide is provided from a pressurized cylinder of carbon dioxide.
82. A plant as claimed in any one of claims 64-80, wherein the feed of a gas containing carbon dioxide is provided from the combustion of natural gas.
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83. A plant as claimed in any of claims 64-80, wherein the plant comprises a gas regulator or supplying pressurized gas containing carbon dioxide to the vessel.
84. A plant as claimed in any one of claims 64-83, where the plant comprises a pump for pumping water into the vessel.
85. A plant as claimed in claim 84, wherein the plant also comprises a break tank for acting as a reservoir of feed water for the plant from which the pump pumps water to the vessel.
86. A plant as claimed in either claim 84 or 85, wherein the pump has a volumetric flowrate capacity at the pressure existing in the vessel that is less than the volumetric flowrate from the dispenser.
87. A plant as claimed in claim 85, wherein the plant is arranged to bubble the vented gases through the water in the break tank.
88. A plant as claimed in either claim 85 or 87, wherein the plant also comprises an inverted bucket located in the break tank, for receiving the vented gases.
89. A plant as claimed in any one of claims 84-88, wherein the volumetric flowrate of the pump is 1- 250mL/min.
90. A plant as claimed in any one of calims 84-88, wherein the volumetric flowrate of the pump is l-50mL/min.
91. A plant as claimed in any one of claims 64-90, wherein the vessel comprises a minimum liquid level mechanism for maintaining a minimum liquid level in the vessel .
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92. A plant as claimed in claim 91, wherein The minimum liquid level mechanism comprises an automatic drain on the outlet from the vessel.
93. A plant as claimed in claim 92, wherein the automatic drain comprises a buoyant ball on a seat.
94. A plant as claimed in any one of claims 64-93, wherein the vessel comprises inner and outer passages in fluid communication and providing opposing flow paths.
95. A plant as claimed in any one of claims 64-93, wherein the vessel comprises a plurality of passages which provide opposing flow paths.
96. A plant as claimed in any one of claims 64-95, wherein the vessel is arranged to receive the gas containing carbon dioxide and the water into the top of the vessel.
97. A plant as claimed in any one of claims 64-96, wherein the vessel is a hose tank.
98. A plant as claimed in any one of claims 64-97, wherein the plant also comprises a backflow mitigation system for mitigating backflow of carbon dioxide gas and/or carbonated water from the vessel into the feed of water.
99. A plant as claimed in any one of claims 64-98, wherein the plant also comprises a controller for controlling water flow into the vessel.
100. A plant as claimed in any one of claims 64-79, 81-99, wherein the venting system comprises a three way valve .
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101. A plant as claimed in claim 100 wherein the three way valve at rest is arranged to enable the vessel to be in fluid communication with the chamber to allow for the accumulation of gas therein and the three way valve is operable to fluidly connect the vessel to the dispenser to enable dispensing of the carbonated water from the vessel.
102. A plant as claimed in either claims 100 or 101, wherein the venting system also comprises a buffer volume between the three way dispensing valve and the dispenser for acting against an unacceptable blast of pressurized gas exiting the dispenser on dispensing.
103. A plant as claimed in any one of claims 100-102, wherein the venting system also comprises a ball float valve located between the three way valve and the dispenser.
104. A plant as claimed in any one of claims 100-102, wherein the three way valve of the venting system is operable to fluidly connect the chamber to the dispenser to enable venting of at least a portion of the accumulated gases .
105. A method for producing and dispensing carbonated water comprising: providing a gas containing carbon dioxide; mixing the gas containing carbon dioxide with water to produce the carbonated water; filling a vessel with the water gas mixture; allowing gas from the water gas mixture in the vessel to accumulate in a chamber; dispensing carbonated water from the vessel as required through a dispenser; and venting at least a portion of the accumulated gas from the chamber in association with dispensing carbonated
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water from the vessel and/or in association with filling the vessel with the water gas mixture.
106. A method as claimed in claim 105, wherein the step of providing the gas containing carbon dioxide comprises the provision of a pressurized cylinder of carbon dioxide.
107. A method as claimed in claim 105, wherein the step of providing the gas containing carbon dioxide comprises producing the carbon dioxide by combusting natural gas .
108. A method as claimed in any one of claims 105-107, wherein the method comprises pumping the water from a feed of water using a pump to the vessel.
109. A method as claimed in claim 108, wherein the method comprises holding a volume of water in a break tank between the feed of water and the pump.
110. A method as claimed in either claim 108 or 109, wherein the pump has a volumetric flowrate capacity at the pressure existing in the vessel that is less than the volumetric flowrate rate from the dispenser.
111. A method as claimed in any one of claims 105-110, wherein the step of mixing occurs in the vessel.
112. A method as claimed in any one of claims 105-111, wherein the step of mixing occurs prior to the water and gas entering the vessel.
113. A method as claimed in any one of claims 105-112, wherein the step of mixing the gas containing carbon dioxide and the water comprises inputting the water and/or gas containing carbon dioxide into the top of the vessel.
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114. A method as claimed in any one of claims 105-113, wherein the step of venting occurs in association with the step of filling the vessel with the water gas mixture.
115. A method as claimed in any one of claims 105-113, wherein the step of venting occurs in association with the step of dispensing carbonated water from the vessel.
116. A method as claimed in any one of claims 105-113, wherein the step of venting occurs in association with both the step of dispensing and the step of filling.
117. A method as claimed in any one of claims 105-114, wherein the step of venting occurs immediately after the step of filling is completed.
118. A method as claimed in any one of claims 105-113 and 111, wherein the step of venting occurs during the step of dispensing.
119. A method as claimed in any one of claims 105-113 and 111, wherein the step of venting occurs immediately after the step of dispensing is completed.
120. A method as claimed in any one of claims 105-113, wherein the step of venting occurs upon commencement of the step of filling.
121. A method as claimed in either claim 114 or 118, wherein the step of venting comprises flowing the carbonated water being dispensed in the step of dispensing through the chamber.
122. A method as claimed in any one of claims 114, 118-119, wherein the step of dispensing comprises rearranging a venting system to bring the dispenser in
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fluid communication with the vessel via the chamber.
123. A method as claimed in claim 122, wherein the step of dispensing comprises rearranging a three way valve .
124. A method as claimed in any one of claims 105-123, the method carried out using the plant as claimed in any one of claims 64-104.
125. A plant for producing and dispensing carbonated water, the plant comprising: a feed of a gas containing carbon dioxide; a feed of water; a mixer for mixing the feeds of gas containing carbon dioxide and water to produce the carbonated water; a vessel for receiving and storing the carbonated water; a dispenser which can be fluidly communicating with the vessel through which carbonated water is dispensed from the vessel; a chamber for accumulating gas from the gas -water mixture held in the vessel; and a pump for pumping water into the vessel, the pump having a volumetric flowrate capacity at the pressure existing in the vessel that is less than the volumetric flowrate from the dispenser.
126. A plant for producing and dispensing carbonated water, the plant comprising: a feed of a gas containing carbon dioxide; a feed of water; a vessel for receiving towards the top of the vessel the feeds of gas containing carbon dioxide and water and storing the produced carbonated water, the vessel being in the form of a hose tank; and a dispenser which can be fluidly communicating with the vessel through which carbonated water is
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dispensed from the vessel.
127. A refrigerative apparatus incorporating a plant as claimed in any one of claims 30-104, 125 and 126.
128. A refrigerative apparatus as claimed in claim 127, wherein the apparatus is a refrigerator.
129. A refrigerative apparatus as claimed in claim 127, wherein the apparatus is a water cooler.
130. A refrigerative apparatus as claimed in claim 128, wherein at least the vessel and the dispenser of the plant are located in the door of the refrigerator.
131. A refrigerative apparatus as claimed in any one of claims 127-130, wherein an upper portion of the vessel of the plant is insulated and a lower portion of the vessel near the bottom of the refrigerative apparatus is made of a heat conducting material for cooling the contents of the vessel.
132. A refrigerative apparatus as claimed in any one of claims 127-131, wherein the vessel comprises heat conducting protrusions from a lower portion of the vessel up into the vessel.
133. A refrigerative apparatus as claimed in claim 131, wherein the lower heat conducting portion has a pathway (s) which allows for the substantially upward flow or air so as increase heat transfer arising from natural convection.
134. A refrigerative apparatus as claimed in any one of claims 127-133, wherein the bottom of the vessel is tapered.
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135. A refrigerative apparatus as claimed in claim 128 or 130, wherein a break tank of the plant for holding water is placed in the refrigerator door.
136. A refrigerative apparatus as claimed in claim 135, wherein an upper portion of the break tank is insulated and a lower portion of the break tank is made of a heat conducting material for cooling the contents of the break tank.
137. A refrigerative apparatus comprising a vessel for storing carbonated water, wherein an upper portion of the vessel is insulated and a lower portion of the vessel near the bottom of the refrigerative apparatus is made of a heat conducting material for cooling the contents of the vessel.
138. A rotary pinch valve comprising a rotor, a stator, at least one rigid backing member and a plurality of movable members suitable for a plurality of flexible tubes.
139. A rotor as claimed in claim 138 comprising at least one essentially circular cam disk.
140. A rotor as claimed in claim 138 comprising a plurality of essentially circular cam disks separated from each other by cam spacer disk(s) and arranged as an essentially cylindrical whole.
141. A stator as claimed in claim 138 comprising at least one stator pinch disk.
142. A stator as claimed in claim 138 comprising a plurality of stator pinch disks separated from one another by stator spacer disk(s) and arranged as an aligned whole.
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143. A stator as claimed in claim 141 and claim 142 comprising at least one pinch slot in any one stator pinch disk.
144. A stator as claimed in claim 143 wherein a pinch slot comprises at least one spring compression base.
145. A stator as claimed in claims 141 -144 comprising at least one removable end plate.
146. A stator as claimed in claim 141-145 comprising a plurality of alignment holes at each of the axially opposite ends of the stator for aligning a plurality of flexible tubes and which alignment holes are separated by alignment gaps in the stator.
147. A stator as claimed in claims 141-146 wherein flexible tubes may be aligned along the stator parallel to the axis of the rotary pinch valve such that a particular flexible tube may pass over at least one pinch slot.
148. A stator as claimed in claims 141-147 comprising pinch slots staggered around the circumference of the stator as well as along its axial length.
149. A stator as claimed in claims 141-148 which is truncated
150. A rotary pinch valve as claimed in claim 138 comprising substantially rigidly attached aligners placed so as to prevent the lateral movement of any particular flexible tube.
151. A rotary pinch valve as claimed claim 138 and claim 150 wherein aligners may be placed at an axial distance as close to the pinch slot as possible to where the particular flexible tube always exhibits an unpinched
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diameter
152. An at least one rigid backing member as claimed in claim 138 comprising a single rigid piece or a plurality of individual rigid backing members, one for each pinch slot and its associated particular flexible tube.
153. An at least one rigid backing member as claimed in claim 138 may be rigidly attached to the stator.
154. An individual rigid backing member, as claimed in claim 152 may be rigidly attached to the stator by at least one radial strut or substantially radial strut.
155. Movable members as claimed in claim 138 each of which has a pinching surface and a curved cam surface.
156. Movable members as claimed in claim 155 each of which has two lateral protrusions.
157. Movable members as claimed in claims 155 and claim 156 any one of which may be placed in any pinch slot of the stator.
158. A rotary pinch valve as claimed in claim 138 and claim 151 comprising a spring mechanism for acting on any movable member so as to ensure appropriate positioning of that particular movable member relative to its particular cam disk.
159. A spring mechanism as claimed in claim 158 comprising a pair of springs each supported at one end by a spring compression base associated with a stator pinch disk and at the other end by a lateral protrusion associated with a movable member.
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160. A spring mechanism as claimed in claim 158 comprising a short elastically deformable sleeve more resilient than a particular flexible tube fitted over the particular flexible tube in the vicinity of the a pinch slot.
161. An individual backing member as claimed in claim 154 wherein radial or substantially radial struts encompass at least three flexible tubes.
162. A stator as claimed in claims 141-149 comprising a series of passages in axial alignment with the alignment gaps where any radial or substantially radial strut or aligner may be placed.
163. A stator as claimed in all previous claims comprising a series of passages in axial alignment with the alignment holes for unimpeded alignment of the plurality of flexible tubes.
164. A stator as claimed in all previous claims comprising a pinch slot which may extend laterally across the axial passage associated with its unpinched flexible tube and either partially or fully into the axial passages occupied by the aligners of its associated flexible tube.
165. A stator as claimed in all previous claims wherein movable members and/or springs may be loaded into the stator from an external position.
166. A stator as claimed in all previous claims comprising an indentation in the vicinity of a particular pinch slot for allowing any movable member to be fitted into a particular pinch slot.
167. A rigid backing member as claimed in claim 152 may be removable from or rotatable about the stator.
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168. A rotary pinch valve as claimed in all previous claims comprising a latching piece consisting of an individual backing member, radial or substantially strut (s) and spring compression base(s).
169. A rotary pinch valve as claimed in claim 168 wherein the latching piece is removable from or rotatable about the stator.
170. A rotary pinch valve as claimed in claim 138 and claim 151 comprising an individual backing member which is removable from or rotatable about its associated radial strut (s) .
171. A rotary pinch valve as claimed in all previous claims wherein the stator may be assembled about the rotor from a number a laminar stator pinch disks alternating with laminar stator spacer disks and with the movable members with or without associated springs, loaded with each appropriate laminar stator pinch disk.
172. A rotary pinch valve as claimed in all previous claims which may be programmable by providing a means to rotate and fix any cam disk relative to another cam disk.
173. A rotary pinch valve as claimed in claim 172 wherein the means to rotate any cam disk relative to another cam disk comprises laminar cam disks and laminar cam spacer disks being detachable and having matching bolt holes or male and female accommodations at regular angular intervals .
174. A rotary pinch valve as claimed in all previous claims comprising a means to maintain the rotor and stator in the same relative axial position.
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175. A rotary pinch valve as claimed in claim 174 wherein the means to maintain the rotor and stator in the same relative axial position comprises at least one removable end plate.
176. A rotary pinch valve as claimed in all previous claims wherein a change of valve state as from open to closed and closed to open is abrupt, as from five to fifteen rotational degrees of the rotor.
177. A rotary pinch valve as claimed in all previous claims wherein a rotor acts upon movable members so as pinch any particular flexible tube against a rigid backing member so as to open and close the particular flexible tube in a desired manner.
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A METHOD AND PLANT FOR PRODUCING CARBONATED WATER
Field of the Invention
The present invention relates to methods and plants for producing carbonated water. In particular, the present invention relates to methods and plants for producing carbonated water incorporated into a refrigerator. The present invention also relates to a rotary pinch valve .
Background of the Invention
A number of systems have been proposed for producing carbonated water in a refrigerator, usually using a supply of carbon dioxide from a cylinder for combination with water such as in US 4850269, WO2006/101435, US 4866949 and US 4970871.
However, such systems may suffer from various problems. One problem is that the amount of carbon dioxide dissolved in the water may reduce over time, due to a build up of extraneous gases. Variability of mains water feed pressure or the requirement for high capacity pumps present other problems .
In addition, such systems may not provide adequate mitigation against the backflow of carbon dioxide gas and/or carbonated water. Where the water feed for the system is sourced from the mains water supply, this is a serious issue for regulatory authorities who will require mitigation against contamination of the mains water by carbon dioxide gas and/or carbonated water. Some systems in attempting to deal with these and other technical issues produce complicated solutions and also place components where access is difficult. Such systems have not met widespread acceptance and a simple, easy to use integrated system would be desirable.
Summary of the Invention
According to a first aspect of the present
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invention, there is provided a method for producing carbonated water, the method comprising the steps of: manufacturing a gas containing carbon dioxide on site; and in situ mixing the carbon dioxide with water to produce carbonated water.
The method may be of particular application for use in relation to a refrigerator. The method may also be of application in other refrigerated devices such as a water cooler. It is to be understood however, that the method may be used in other applications, such as in respect of a fermentation plant where the fermentation gases can be captured and sent to the plant for the production of carbonated water. The method may operate on a batch or continuous basis. The method may operate on an intermittent or non- intermittent basis.
The step of manufacturing a gas containing carbon dioxide may comprise any suitable physical or chemical method.
The step of manufacturing a gas containing carbon dioxide may comprise extracting the gas containing carbon dioxide from a larger volume of gas, such as from contaminated air, for example. In another arrangement, the step of manufacturing a gas containing carbon dioxide may comprise conducting a chemical reaction to produce carbon dioxide.
In one embodiment, the chemical reaction is a fermentation reaction. In another particular embodiment, the chemical reaction is a combustion reaction. In another embodiment, the chemical reaction is a steam reformation reaction of hydrocarbons .
The method may further comprise the step of purifying the gas containing carbon dioxide. The step of purifying the carbon dioxide may occur by any suitable mechanism such as filtration, electrodialysis, swing sorption, scrubbing or demisting,
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for example .
The step of purification preferably occurs by- swing sorption.
The swing sorption may be a thermal, pressure, microwave or electrical swing sorption mechanism or any combination thereof.
The step of purification may comprise combined thermal and pressure swing sorption.
In another arrangement, the step of purification may comprise filtering the gas containing carbon dioxide through at least one membrane, preferably two membranes.
The method may also comprise the step of pressurising the purified carbon dioxide.
The step of pressurising the carbon dioxide thus occur simultaneously with the step of purifying the gas containing carbon dioxide.
The method may also comprise the step of pressurising the water which the purified carbon dioxide is mixed with. The method may also comprise the step of storing the carbonated water produced in a pressurised vessel.
The stored carbonated water may be chilled to a temperature of approximately 4 0 C.
The carbonated water produced according to the method of this aspect of the invention may have a concentration of carbon dioxide of approximately 4 volumes (at atmospheric temperature and pressure) per volume of water.
The step of manufacturing the gas containing carbon dioxide may comprise combusting a hydrocarbon fuel.
The hydrocarbon fuel may be natural gas.
The natural gas may be supplied from the reticulated supply in urban and commercial areas .
The step of combusting natural gas may occur in approximately 20% by volume excess air.
The gas produced by combustion of the natural gas may contain approximately 10% by volume carbon dioxide (on
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a water-free basis) .
The method may also comprise the step of cooling the gas containing carbon dioxide produced by the combustion reaction. The step of sorption of the carbon dioxide may comprise compressing the gas containing carbon dioxide into a sorber/desorber using a compressor.
The method may also comprise the step of obtaining water from a water supply for mixing with the carbon dioxide.
The water is preferably supplied from the mains water reticulated supply available in urban and commercial areas.
The method may further comprise the step of buffering the reticulated mains water supply from any carbon dioxide or pressurised water.
The step of buffering the reticulated mains water supply may comprise supplying mains water to a cool water reservoir from which water can be drawn to use in the step of mixing the carbon dioxide with water.
The step of purification of the gas containing carbon dioxide by swing sorption may comprise the steps of sorption of the carbon dioxide on a regenerable sorbent in a sorber/desorber followed by desorption of the carbon dioxide from the sorbent.
The step of sorption of the carbon dioxide may occur under the influence of raised pressure.
The step of sorption may occur under the influence of cooling. The step of desorption may occur under the influence of lowered pressure.
The step of desorption may occur under the influence of heating.
The step of desorption may occur under the influence of microwave or electrical stimulation or heating.
The step of purification by swing sorption may
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also comprise the step of pressure release by letting down the pressure in the sorber/desorber to atmospheric pressure.
The step of purification of carbon dioxide by swing sorption may also comprise the step of vacuum purging the sorber/desorber of extraneous gases by application of a vacuum on the sorber/desorber.
The compressor for the step of sorption of the carbon dioxide may be a first liquid ring compressor, however, it may be any other suitable type of compressor.
The method may also comprise the step of recycling the liquid ejected from the first liquid ring compressor outlet to its inlet.
The method may also comprise the step of cooling the recycled water from the outlet to the inlet of the first liquid ring compressor.
This cooling may be achieved using the cool water reservoir. In another embodiment, this cooling may be achieved using air cooling. The method may also comprise the step of using the water from the combustion reaction as the liquid in the first liquid ring compressor.
The step of sorption may comprise relieving gases from the sorber/desorber at a design relief pressure.
The design relief pressure may be approximately 50 - 75 psig.
The step of sorption may comprise using the relief gases to cool a combustion unit in which the natural gas is being combusted.
The sorption step may also comprise pumping cooling liquid through heat exchanger tubes in the sorber/desorber .
The cooling liquid may be preferably water. The pump may be a second liquid ring compressor.
However, it may be any suitable pump.
Pumping of the cooling liquid may comprise
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pumping water from the cool water reservoir through the heat exchanger tubes in the sorber/desorber and returning the water thereafter to the cool water reservoir.
The water pumped by the second liquid ring compressor to cool the sorber/desorber may be derived as a take-off on the casing of the second liquid ring compressor.
Pumping of the cooling liquid may comprise pumping condensate in the first liquid ring compressor through heat exchange tubing, cooled within the refrigerator, and then through heat exchange tubes in the sorber/desorber and returning the condensate to the first liquid ring compressor suction.
In this embodiment, the heat exchange tubing cooled within the refrigerator may comprise air cooling or heat exchange tubing passing through a reservoir of cyclic defrost water from the refrigerator.
At least a portion of the condensate water pumped by the first liquid ring compressor may comprise as a take-off on the casing of the first liquid ring compressor.
The sorption step may also comprise cooling a combustion unit in which natural gas is being combusted using cooling water. In this embodiment, the cooling water may be pumped through a jacket of the combustion unit. This may or may not be carried out on start-up of the method.
The cooling water for cooling the combustion unit may be the water at the outlet of the heat exchange tubes of the sorber/desorber.
The step of pressure release may comprise using the pressure release gases to cool a combustion unit in which natural gas is being combusted.
The step of vacuum purge may comprise applying a pressure below atmospheric pressure to the sorber/desorber .
The application of the pressure below
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atmospheric pressure on the sorber/desorber may be carried out using a compressor, preferably the first liquid ring compressor and more preferably also the second liquid ring compressor. The method may also comprise the step of recovering carbon dioxide from the vacuum purged gases by dissolution of the carbon dioxide in water.
The water may be the water within a liquid ring compressor. The step of recovering the carbon dioxide from the purged gases may comprise recycling the purged gases across the first liquid ring compressor and preferably also across the second liquid ring compressor.
The step of recovering carbon dioxide from the purged gases may comprise directing the purge gases to atmosphere under pressure through a relief valve on a downstream separator associated with a liquid ring compressor.
The step of recovering carbon dioxide from the vacuum purge gases may comprise directing the purged gases through a second sorber/desorber, preferably under pressure through a relief valve, to atmosphere.
The step of pressure release and the step of vacuum purge may be part of the same step with the same flow path through a compressor (s) to atmosphere.
The method may comprise the step of pressure release on the second sorber/desorber.
The method may also comprise the step of switching from the step of vacuum purge to the step of desorption at an optimum pressure between expelling extraneous gases and losing carbon dioxide.
The step of desorption may comprise applying pressure below atmosphere to the sorber/desorber.
The pressure applied during the desorption step may be lower than the pressure applied during the vacuum purge step.
The compressor may be used to apply the pressure
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during desorption on the sorber/desorber .
The first liquid ring compressor and preferably also the second liquid ring compressor may be used to apply the pressure during desorption on the sorber/desorber.
The step of desorption may comprise applying heat to the sorbent by flowing heated water through the heat exchanger tubes in the sorbent.
The heated water may be heated sufficiently to enter the heat exchanger tubes as steam.
The heated water may be heated using a combustion unit in which the natural gas is combusted.
The step of desorption may comprise applying the pressure below atmosphere equally to the second sorber/desorber as well as to the first mentioned sorber/desorber .
The method may further comprise the step of venting gases to further remove and act against the build up of extraneous gases. The step of venting may comprise enriching the gases to be vented in extraneous gases in the vapour space of a vessel by contacting the desorbed gases in the vessel with water at least once, on the basis of the preferential dissolution of the carbon dioxide in water. The step of venting may occur solely in the vessel in which the produced carbonated water is stored. However, the step of venting may also be preferably carried out at least partially in a separate vessel to the storage vessel. In another embodiment, the separate vessel in which the step of venting may be carried out is a bottom level float separator.
The method may also comprise the step of mitigating any backflow of mains water into the sorber/desorber.
The step of mitigating backflow of mains water into the sorber/desorber may comprise using at least one
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check valve to act against fluid flow in a direction towards the sorber/desorber .
The method of mitigating backflow of mains water into the sorber/desorber may comprise desorbing into the vapour space of a vessel.
The step of mitigating backflow of mains water into the sorber/desorber may comprise having the condensate water formed in the combustion reaction as the liquid in the liquid ring compressor. The method may comprise the step of using the compressor which compresses gas into the sorber/desorber to act as a fluid displacement pump to pressurise the water which is mixed with the carbon dioxide to produce carbonated water. The step of pressurising the water using the compressor as a fluid displacement pump may comprise pressurising water in a fluid displacement vessel using compressed gases from the compressor.
This may or may not occur simultaneously with the step of sorption.
The step of water pressurisation may also comprise pumping the pressurised water from the fluid displacement vessel into another vessel. This step preferably occurs as the water is pressurised. In another embodiment, the another vessel may be the separate venting vessel.
The venting vessel, at some point in the method, may be in fluid communication with the storage vessel in which the carbonated water is stored. The step of venting may be carried out in the venting vessel.
The method may also comprise the step of filling the fluid displacement vessel with water.
The step of filling the fluid displacement vessel with water may comprise filling the fluid displacement vessel under gravity from the cool water reservoir.
The step of filling the fluid displacement vessel
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with water may occur after the step of water pressurisation in a previous cycle or the same cycle of the method.
The step of venting using the venting vessel may occur after the venting vessel is nominally filled with water.
The step of recovering carbon dioxide from vented gas, may comprise flowing vented gas through the fluid displacement vessel after the step of filling the fluid displacement vessel.
According to a second aspect of the present invention, there is provided a plant for producing carbonated water, the plant comprising an apparatus for manufacturing a gas containing carbon dioxide and a mixer for mixing the carbon dioxide with water to produce carbonated water.
The plant may also comprise a purifier for purifying the gas containing carbon dioxide.
The plant may also comprise at least one primary compressor for compressing the gas containing carbon dioxide which is mixed with the water to produce carbonated water.
The plant may also comprise at least one secondary compressor for pressurising the water which is mixed with the carbon dioxide to produce carbonated water.
The primary compressor (s) may be a liquid ring compressor (s) .
Any primary compressor may also perform the function of the secondary compressor, preferably as a liquid ring compressor.
In another embodiment, the primary compressor (s) may be any type of suitable compressor (s) for compressing gases such as a piston, diaphragm or peristaltic compressor. In this embodiment, the secondary compressor (s) may be any type of suitable pump(s) for pressurising liquids such as a piston, diaphragm or peristaltic pump.
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The primary compressor (s) may be of a type of compressor which draws in minimal air from atmosphere when used as a vacuum pump.
Where the primary compressor (s) is a piston compressor (s) , the piston compressor (s) may comprise a double acting two stage articulating piston compressor (s) . In this embodiment, the piston compressor (s) may comprise seals between the piston reciprocating shaft and the housing for minimising air ingress. In this embodiment, the reciprocating shaft of the piston may enter the housing via the shaft seal into a more highly pressurised second stage ensuring that leakage past the shaft seal is mainly to atmosphere (as opposed to from atmosphere) . The purifier may comprise a sorber/desorber for purifying the gas containing carbon dioxide by swing sorption.
The sorber/desorber may be a pressure swing sorber/desorber . In this embodiment, the plant may comprise at least one tertiary compressor for compressing the gas containing carbon dioxide into the sorber/desorber.
The tertiary compressor (s) may be a liquid ring compressor (s) . In another embodiment, the tertiary compressor (s) may be any type of suitable compressor for compressing gases, such as a piston, diaphragm or peristaltic compressor.
Any primary compressor may also perform the function of the tertiary compressor.
Any primary compressor, preferably as a liquid ring compressor may also perform the function of either the secondary compressor or the tertiary compressor but not both (secondary compressor and tertiary compressor) . The primary and tertiary compressors may have cooling between two successive compressors in series. This cooling may preferably be sufficient to induce substantial
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condensation of water in the compressed gas.
Where the compressor (s) is a peristaltic compressor (s) it may comprise a multi channel compressor (s) with different diameter tubing. The sorber/desorber may be a thermal swing sorber/desorber, preferably in addition to being a pressure swing sorber/desorber.
The purifier may comprise a second sorber/desorber for recovery of carbon dioxide from the vacuum purge gases of the sorber/desorber.
The sorber/desorber may have heat exchanger tubes for the flow therethrough of a cooling fluid during sorption and a heating fluid during desorption. Preferably, the cooling and heating fluids are water. The plant may also comprise at least one primary pump for pumping water for cooling and/or heating through the heat exchanger tubes of the sorber/desorber.
Any secondary compressor may also provide the function of the primary pump. Any primary or tertiary compressor preferably as a liquid ring compressor, may also provide the function of the primary pump.
The first liquid ring compressor may comprise at least one first liquid ring compressor. If more than one then they are preferably arranged in series.
The second liquid ring compressor may comprise at least one second liquid ring compressor. If more than one then they are preferably arranged in series.
The plant may comprise a first liquid ring compressor stage which provides functions of the primary and tertiary compressors.
The plant may comprise a second liquid ring compressor stage which provides functions of the primary and secondary compressors and the primary pump. The plant may comprise a first liquid ring compressor stage which provides functions of primary and tertiary compressors and primary pump.
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The plant may comprise a second liquid ring compressor stage which provides functions of primary and secondary compressors.
The sorber/desorber may contain a sorbent upon which carbon dioxide is preferentially sorbed.
The second sorber/desorber may contain a sorbent on which carbon dioxide is preferentially sorbed.
The sorbent in the sorber/desorber may be a nontoxic sorbent . The sorbent may be an aqueous based liquid sorbent .
In another embodiment, the sorbent may be solid and essentially immiscible with water.
The sorbent may comprise the salts of an alkali metal or may be a metal oxide.
In other embodiments, the sorbent may be any suitable solid sorbent such as molecular sieves and sorbents comprising porous substrates with amine function compounds either physically or chemically tethered to them.
The sorbent may have a polystyrene, silica gel, polyether, acrylic or carbon molecular sieve backbone and amine functionality, preferably tertiary amine functionality. The sorbent may be an ion exchange resin with primary, secondary or tertiary functional groups or any combination thereof.
The sorbent may be a weak base anion exchange resin with tertiary amine functionality and a polystyrene backbone such as Rohm and Haas IRA 96, or Dowex Marathon
WBA-2 for example.
Where the sorbent is a weak base ion exchange resin, the functional amine group may be in the free base form. The sorbent may be macroporous.
The sorbent may have tertiary amine functionality.
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The plant may be supplied with water from a water supply.
The plant may also comprise a cool water reservoir for providing a buffer between the water supply and any carbon dioxide or pressurised water in the plant.
The cool water reservoir may have a level control valve, preferably a float valve which is connected to the water supply, for maintaining the water level in the cool water reservoir. The cool water reservoir may act as an inventory for the water in the plant.
The cool water reservoir may be supplied from the mains water supply which is reticulate in urban and commercial areas. The plant may comprise a reservoir of cyclic defrost water from the refrigerator, for cooling circulatory process water via heat exchange tubes or as a source of circulatory process water itself.
The plant may also comprise a product drawdown vessel for storing the carbonated water produced by the plant.
The product drawdown vessel may also be for dispensing the carbonated water therefrom.
The product drawdown vessel even when nominally full may have a significant freeboard of gaseous space to act as a propellant for dispensing.
The product drawdown vessel may have an automatic drain float valve for preventing the carbonated water from being dispensed from the product drawdown vessel when the carbonated water is at a low level in the vessel.
The apparatus for manufacturing a gas containing carbon dioxide may be a combustion unit for combusting a hydrocarbon in a combustion reaction.
Preferably, the hydrocarbon is natural gas. The natural gas is preferably supplied from the reticulated supply in most urban and commercial areas.
The combustion unit may comprise a burner firing
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into a firebox.
The combustion unit may also comprise at least one, preferably two, jackets for the flow therethrough of fluid to cool the firebox. Where the burner has a thermoelectric valve flame safeguard, the thermoelectric valve may be opened for ignition using the capabilities of the system.
Any of the combustion unit, burner, flame safeguard and ignition and re-ignition devices may be shared with another appliance.
Individual compressors of the plant may be driven by the same or separate motors .
The first liquid ring compressor stage may comprise a first top level float separator, at least one first liquid ring compressor (if more than one they are preferably arranged in series) and a first separator.
The second liquid ring compressor stage may comprise a second top level float separator, at least one second liquid ring compressor (if more than one they are preferably arranged in series) and a second separator.
The liquid in the first liquid ring compressor may be the condensate water formed in the combustion reaction.
The first separator may be for capture at least some of the ejected liquid from the outlet of the first liquid ring compressor and return to the suction side of the first liquid ring compressor.
The first separator may return the ejected liquid via the first top level float separator. The returned ejected liquid may be cooled by flow through heat exchange tubing in the cool water reservoir.
In another embodiment, the returned ejected liquid may be cooled by flow through air cooled heat exchange tubing. The first top level float separator may comprise a high level float valve for preventing the float separator from over flowing with liquid.
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The high level float valve may close off the ejected liquid inlet from the first separator when the liquid level becomes to high in the first top level float separator. The first top level float separator and the first separator may have a combined volume which is sufficient to hold the volume of condensate produced during a single operational cycle of the plant.
The second top level float separator may comprise a high level float valve for preventing the float separator from over flowing with liquid.
The high level float valve may close off the ejected liquid inlet from the second separator when the liquid level becomes to high in the second top level float separator.
The second top level float separator and the second separator may have a combined volume which is sufficient to hold the volume of condensate produced during a single operational cycle of the plant. In another embodiment, the first and/or second liquid ring compressor stage may comprise an automatic drain on its discharge and a separator on its suction.
The sorbent may require a moist environment in order to function most efficiently. The moist environment may be provided in the sorber/desorber by the humidity in the gas stream or by condensate overflow exiting the first separator.
The plant may comprise a dewatering unit which removes water from feed gases to the sorber/desorber, preferably by condensation of the compressed gases in a refrigerated vessel with subsequent drainage of the condensate to the evaporator.
The sorber/desorber may comprise a relief valve for relief of gas depleted of carbon dioxide during sorption at a design relief pressure.
The relief valve may direct gas to one of the jackets of the combustion unit to cool the firebox.
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The relief valve may be located towards the top of the sorber/desorber so as to act against possible particulate contamination of the relief valve from the friable sorbent resin. The relief valve preferably has a design relief pressure of approximately 50 to 75psig.
The second liquid ring compressor stage may draw water from the cool water reservoir via during sorption.
The second liquid ring compressor may comprise a take-off on its casing for providing the cooling fluid flow during sorption.
The sorber/desorber may be positioned outside of the refrigeration space of a refrigerator which the plant is associated with. In another embodiment, the sorber/desorber may be placed inside the refrigeration space. In this embodiment, cooling during sorption would be provided by the refrigerator and cooling water from the cool water reservoir would not be required. The outlet from the sorber/desorber through which relief gas is directed during pressure release may be located slightly above the bottom of the sorber/desorber. This is to leave a well of condensate water at the bottom of the sorber/desorber for acting against the ion exchange resin drying out when not in use, with consequent loss in capacity.
The second sorber/desorber may be provided with sufficient humidity or condensate water from the plant to prevent it from drying out. The first and second liquid ring compressor stages may also be for vacuum purging the sorber/desorber to extract a substantial amount of the extraneous gases from the sorber/desorber after sorption.
The extraneous gases generally comprise mostly oxygen and nitrogen, particularly nitrogen.
The plant may also comprise during vacuum purging, a recycle of the gas exiting the first separator
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of the first liquid ring compressor stage to the gas flow into the first top float separator.
This recycle may be for recovering carbon dioxide from the gas being vacuum purged by dissolution of the carbon dioxide in the water in the first liquid ring compressor stage.
The plant may also comprise during vacuum purging, a recycle of the gas exiting the second separator of the second liquid ring compressor stage to the gas flow into the second top float separator.
This recycle may be for recovering carbon dioxide from the gas being vacuum purged by dissolution of the carbon dioxide in the water in the second liquid ring compressor stage. The plant may also comprise a vacuum valve to effect a change from vacuum purge to desorption at a designed pressure.
The vacuum valve may comprise a pair of parallel tubes, one being collapsible at the designed low pressure or having an in line check valve with an appropriately set cracking pressure and the other tube being non-collapsible at the designed or lower pressures.
The vacuum valve may be located on the suction (inlet) side of the first primary compressor. The first and second liquid ring compressor stages may also be for applying a low pressure on the sorber/desorber during desorption.
The combustion unit may also be for heating water, the hot water or steam produced being for use in heating the sorber/desorber during desorption.
The second liquid ring compressor may also be the mixer for mixing the carbon dioxide with water to produce carbonated water.
The plant may also comprise one or more venting vessels for venting desorbed gases from the vapour space thereof, so as to further remove and act against the build up of extraneous gases .
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The gases to be vented may be enriched in extraneous gases in the vapour space of the vessel by one or more contacts of the desorbed gases in the one or more venting vessels with water. The one or more venting vessels may comprise a bottom level float separator.
The bottom level float separator may comprise a float valve for closing the flow of liquid from the bottom level float separator to the second separator at a design low level in the bottom level float separator.
The one or more venting vessels may also comprise the product drawdown vessel. In this embodiment, the product drawdown vessel may also comprise a relief valve for venting of extraneous gases. In this embodiment it is not necessary for the plant to have the bottom level float separator.
The plant may also comprise a PDV fill control mechanism for controlling filling of the product drawdown vessel. The PDV fill control mechanism may comprise a low level switch on the product drawdown vessel for activating filling of the product drawdown vessel with carbonated water upon detection of a design low liquid level.
The PDV fill control mechanism may comprise a low pressure switch on the product drawdown vessel for activating input of pressurised carbon dioxide gas to the product drawdown vessel upon detection of a design low pressure level.
The PDV fill control mechanism may also be for initiating start-up of operation of the plant.
The PDV fill control mechanism may also comprise a low level start-up mechanism which acts against the motor being sent a mixed alternating start-up signal, due to any surface turbulence caused by carbonated water being withdrawn from the product drawdown vessel.
The low pressure switch may be separated from the vapour space in the product drawdown vessel by a membrane.
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The PDV fill control mechanism may also comprise a controllable valve on the liquid recycle between the second separator and the second top level float separator. On a low level start, the controllable valve prevents flow in the liquid recycle line and on a low pressure start allows flow in the liquid recycle line.
The controllable valve is preferably a solenoid valve. It may be an on/off or a three way valve.
On a low pressure start water may be drawn into the second top level separator from the product drawdown vessel rather than from the second separator.
In this embodiment there may be no need for the second separator or the recycle line from it and the controllable valve may be a three way valve. The three way valve may preferably isolate flow from the product drawdown vessel to the second top level float separator in the event of power failure.
Where the secondary compressor is not a liquid ring compressor, the PDV fill control mechanism may comprise a controllable valve on the secondary compressor suction and/or a recycle line from discharge to suction on the secondary compressor. In this embodiment, the PDV fill control mechanism may also comprise a downstream check valve on the secondary compressor discharge. In this embodiment on a low level start, the controllable valve may be open on the suction or closed on the recycle line of the secondary compressor.
The PDV fill control mechanism may also comprise a processor for monitoring unacceptable gas leakage from the product drawdown vessel by calculating the ratio of low pressure starts to low level starts and comparing it to an acceptable ratio.
The plant may also comprise a first check valve for acting to prevent liquid loss from the plant, particularly from the first liquid ring compression stage, when the plant is at rest.
The plant may also comprise a back flow
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mitigation system for mitigating any backflow of mains water into the sorber/desorber .
Preferably, the backflow mitigation system is designed to mitigate backflow even when there is no power supplied to the plant.
The back flow mitigation system may comprise arranging the sorber/desorber to desorb into the vapour space of the venting vessel or storage vessel.
The backflow mitigation system may comprise a check valve located between the sorber/desorber and the cool water reservoir.
The back flow mitigation system may also comprise a check valve between the venting vessel and the sorber/desorber . The check valve of the back flow mitigation system is preferably located between the venting vessel and the compressor discharge.
The check valve of the backflow mitigation system may at all times only allow fluid flow away from the sorber/desorber.
The check valve of the backflow mitigation system maybe located between the second liquid ring compression stage, which uses mains water, and the first liquid ring compression stage, which does not. The backflow mitigation system may also comprise demisters in the first and second top level float separators for extracting excess moisture from the gas in the gas space in the top level float separators.
The float valve in the second top level float separator may also form part of the backflow mitigation system by acting against the second top level float separator from overfilling with water and backflowing.
The plant may comprise a pump for circulating the cooling and/or heating water during sorption and desorption and a compressor for compressing the purified carbon dioxide, for compressing the gas containing carbon dioxide into the sorber/desorber and also for pressurising
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the mains water by using compressed gas from the compressor to act as a fluid displacement pump.
In this embodiment, the plant may also comprise a fluid displacement vessel for holding water to be pressurised by the compressor acting as a fluid displacement pump by compressing gas into the fluid displacement vessel.
In this embodiment, the venting vessel may also be for receiving the pressurised water from the fluid . displacement vessel.
The fluid displacement vessel may be located relative to the cool water reservoir to enable the fluid displacement vessel to be gravity filled from the cool water reservoir. The plant may comprise a vacuum fill vessel for introducing the water into the plant.
In this embodiment, vacuum may be applied to the vacuum fill vessel using the compressor so as to evacuate the mainly carbon dioxide to the vapour space of the product drawdown vessel whereafter the vacuum in the vacuum fill vessel draws in water from the cool water reservoir.
At least one vacuum fill cycle may be performed for a full operational cycle of the plant. The plant may also comprise a valve system for directing the fluid flow during the operation of the plant at the different operation steps.
The valve system may comprise a plurality of valves . The valve system may comprise a rotary valve, preferably a rotary pinch valve.
In this embodiment, the rotary valve may be driven by the same motor that drives any one or more the pumps or compressors in the plant, preferably through a speed reduction unit.
The valve system may comprise a three position valve, preferably a pinch or spool valve relying on the
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pressures of vacuum, atmospheric pressure and sorber/desorber relief pressure for positioning.
Where a valve of the valve system is a pinch valve and under vacuum, at some time during operation of the plant, that valve may be in the open state at rest.
The plant may also comprise a pre-cooler for cooling the combustion gases from the combustion unit.
In one embodiment, the pre-cooler may be finned heat exchanger tubes. In another embodiment, the pre-cooler may comprise a vessel containing water, through which the combustion gases are bubbled. In this embodiment, the pre- cooler is therefore also for scrubbing and dehumidifying the combustion gases from the combustion unit. The heat lost to the water in the pre-cooler from the combustion gases may be used as a heat source for heating the sorber/desorber during desorption.
The burner during desorption may be arranged to provide heat to the water in the pre-cooler via heat exchange through the inner and outer tubes of the combustion gases inlet, so as to replenish heat lost to the sorber/desorber.
The pre-cooler may have heat exchange tubes for the flow therethrough of water to be heated during desorption.
The pre-cooler may have an inlet for mitigating noise created by the downward flow of condensation against the upward flow of combustion gases entering the pre- cooler from the combustion unit. The pre-cooler inlet may comprise two tubes; an inner tube and an outer tube, the inner tube being located inside the outer tube.
The inner tube may be for receiving the combustion gases from the combustion unit at its lower end.
The outer tube may be sealed at its upper end, to prevent gases from leaving the outer tube at its upper
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end.
The outer tube may have spaces provided at the lower end of the outer tube for the gases to pass out of the outer tube and into the pre-cooler. In other arrangements, the inlet of the pre- cooler could be an inlet tube surrounded by insulation material or a venturi nozzle, which would also mitigate noise.
The top of the inner tube may be above the water level in the pre-cooler when no combustion gases are passing through the pre-cooler and the gas head space in the pre-cooler is at atmospheric position.
The top of the outer tube may be submerged below the water level in the pre-cooler when combustion gases flow through the pre-cooler.
The plant may also comprise a water balance system for balancing the water produced in the combustion reaction by disposing of water from the plant.
The water balance system may comprise an evaporator tray on which the disposed water may be evaporated.
Evaporation on the evaporator tray may occur using the waste heat of the refrigerator in relation to which the plant is associated. Evaporation may also occur using other process heat or ambient thermal energy.
The disposed water may comprise accumulated water within the first liquid ring compressor stage.
The disposed water may comprise accumulated water within the second liquid ring compressor stage. The disposed water may also comprise accumulated water within the sorber/desorber .
The disposed water may also comprise water accumulated within the pre-cooler.
In another arrangement, the disposed water may be collected rather than sent to an evaporator tray, either for physical disposal or incorporation into the carbonated water product.
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Where a liquid aqueous sorbent is used, the water balance system may comprise a negative process water balance on the sorber/desorber using makeup water from process condensate or cyclic defrost water produced by the refrigerator to add to the sorber/desorber.
The water balance system may also comprise a gravity drainage leg on the pre-cooler.
The drainage leg may control the water volume in the pre-cooler by allowing excess water above a design water level to exit the pre-cooler through the drainage leg under gravity, at an appropriate time in the operation of the plant.
The drainage leg may have a valve to act against air ingress to the pre-cooler through the drainage leg. The drainage leg may also be for the input of make-up to the pre-cooler in the case where the volume of water in the pre-cooler is such that the water is below a design water level.
The plant may also comprise a second backflow mitigation system for mitigating backflow into the pre- cooler.
The second backflow mitigation system may also be designed to mitigate backflow even when there is no power supplied to the plant. The second backflow mitigation system maycomprise a check valve between the compressor suction and the pre-cooler vapour space.
The purifier may comprise at least one membrane. The purifier may comprise two membranes. The at least one membrane may be an anion exchange membrane, or any other suitable type of membrane.
In this embodiment, the plant may comprise a further compressor for each of the membranes, for forcing the gas containing carbon dioxide through its respective membrane .
The further compressor (s) may be any suitable type of compressor, including a liquid ring compressor.
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The sorber/desorber of the plant may comprise a membrane contactor.
Where a substantially purified carbon dioxide gas is available, as a by-product or otherwise, the plant may comprise one or more liquid ring compressors for pressurising the carbon dioxide and water and the mixing thereof to produce carbonated water.
The plant may comprise or is integrable with a soft drink plant for producing and dispensing soft drinks. The vapour space of the product drawdown vessel may be used to carbonate syrup in a syrup package and pressurise the syrup for combination with carbonated water from the product drawdown vessel.
The vapour space of the product drawdown vessel may be used to carbonate a removable container containing uncarbonated water and uncarbonated syrup.
Air in the top of a syrup package or removable container may be vented to atmosphere via a three way valve by at least one pressurising and venting step. The plant may be of particular application for installation in relation to a refrigerator or other refrigerated device such as a water cooler. It is to be understood however, that the plant could be used in other applications, such as in respect of a fermentation plant where the fermentation gases can be captured and sent to the plant for the production of carbonated water.
According to a third aspect of the present invention, there is provided a plant for producing and dispensing carbonated water, the plant comprising: a feed of a gas containing carbon dioxide; a feed of water; a mixer for mixing the feeds of gas containing carbon dioxide and water to produce the carbonated water; a vessel for receiving and storing the carbonated water; a dispenser which can be fluidly communicating with the vessel through which carbonated water is
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dispensed from the vessel; a chamber for accumulating gas from the gas-water mixture held in the vessel; and a venting system operable to enable venting of at least a portion of the gas accumulated in the chamber in association with dispensing of the carbonated water from the vessel and/or in association with filling of the vessel .
The chamber may be located between the vessel and the dispenser.
The vessel may also be the mixer and therefore may receive and mix the feeds of gas containing carbon dioxide and water.
The venting system may be operable only in association with dispensing of the carbonated water from the vessel.
The venting system may be operable only in association with filling of the vessel.
The venting system may be operable in association with both dispensing and filling of the vessel.
The venting system may be operable to enable venting of at least a portion of the accumulated gas upon dispensing of the carbonated water from the vessel.
The venting system may be operable to enable venting of at least a portion of the accumulated gas immediately after dispensing from the vessel has been completed.
The venting system may be operable to enable venting of at least a portion of the accumulated gas immediately after filling of the vessel is completed.
The venting system may be operable to enable venting of at least a portion of the accumulated gas on commencement of filling.
The venting system may be operable to vent accumulated gas through the dispenser.
The venting system may enable venting of at least a portion of the gas accumulated in the chamber by flowing
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the carbonated water being dispensed through the chamber.
The venting system may be operable to enable the vented gas to flow in advance of the carbonated water being dispensed. The venting system may be operable to enable venting of at least a portion of the gas accumulated in the chamber by opening the chamber to atmosphere.
The venting system may be operable to isolate the chamber when venting at least a portion of the gas accumulated in the chamber.
The venting system may be operable to vent accumulated gas in parallel with the dispenser, preferably upon dispensing of the carbonated water from the vessel.
The venting system may comprise a restrictive device for restricting the flow of gas being vented from the chamber.
The restrictive device may be located between the chamber and atmosphere.
The restrictive device may be an orifice or a pressure relief valve which may have cracking pressure less than the equilibrium pressure in the vessel.
The venting system may comprise a multiport valve operable to vent at least a portion of the gas accumulated in the chamber, preferably in parallel with dispensing of carbonated water through the dispenser.
The chamber may be vented to the atmosphere via a check valve upstream or downstream of the external chamber.
In another arrangement, the chamber may be vented to atmosphere via a suitable length of narrow diameter tubing downstream of the external chamber.
The chamber may be located externally or internally of the vessel or may be located in part external to the vessel and in part internal to the vessel. Where the chamber or a portion of the chamber is located internally of the vessel, the plant may comprise a level control valve for creating the chamber or chamber
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portion above a water level inside the vessel. The level control valve may be a float valve.
The feed of a gas containing carbon dioxide may be pressurized above atmospheric pressure. The feed of a gas containing carbon dioxide may be a feed of close to pure carbon dioxide.
The feed of a gas containing carbon dioxide may be provided from a pressurized cylinder of carbon dioxide.
The feed of a gas containing carbon dioxide may be provided from any other suitable source, such as from the combustion of natural gas for example.
The feed of water may be pressurized above atmospheric pressure.
The feed of water may be provided from a mains water supply.
The plant may comprise a suitable pump or pumps for pressurizing the water and/or the gas containing carbon dioxide from their respective feed pressures.
The plant may be incorporated into a refrigerator.
The plant may be incorporated into a water cooler.
The carbonated water may be dispensed from the plant incorporated into the refrigerator in conjunction with cold still water.
The plant may also comprise a still water holding tank for holding a volume of water.
The still water holding tank is fluidly located between the feed of water and the vessel. The plant may also comprise a treatment device for treating the feed of water.
The treatment device may be fluidly located before the still water holding tank.
The treatment device may comprise a carbon filter.
The plant may comprise a gas regulator or supplying pressurized gas containing carbon dioxide to the
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vessel .
The plant may comprise a pump for pumping water into the vessel.
Where the plant comprises a pump the plant may also comprise a break tank for acting as a reservoir of feed water for the plant from which the pump pumps water to the vessel.
The break tank may be located between the pump and the still water holding tank. The break tank may have a level control valve, preferably a float valve, operable to enable water to be fed into the break tank from the water feed.
The break tank may also act as a backflow mitigation system for mitigating against the backflow of water to the feed of water.
The break tank may be provided with an air gap between the maximum water level in the break tank and the level at which the level control valve operates to enable water to enter the break tank. The break tank may have a drain above a maximum water level in the break tank.
The break tank drain may be fluidly connected to an evaporator tray beneath the refrigerator.
The pump may be an electrically driven pump or a pneumatic pump such as a double acting diaphragm pump or double acting piston pump.
Where the pump is a pneumatic pump it may use the pressure of the compressed gas containing carbon dioxide to power the pump. The gas pressure used to power the pump may be the pressure of the gas pressure regulator.
The pump may have a volumetric flowrate capacity at the pressure existing in the vessel that is less than the volumetric flowrate from the dispenser. The volumetric flowrate of the pump may be 1-
250mL/min, preferably l-50mL/min.
The pump may be activated solely by the maximum
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water level in the vessel.
Where the pump is a pneumatic pump the plant may comprise a three way valve downstream of the gas pressure regulator operable to direct gas containing carbon dioxide to the pneumatic pump when filling the vessel or directly into the vessel via a pump check valve when in the rest position.
The pump check valve may have a sufficient cracking pressure for maintaining a suitable gas pressure differential for pumping into the vessel.
The gas exhausted from the pneumatic pump and the water pumped by the pneumatic pump may enter the vessel separately.
In another arrangement, the water and the gas containing carbon dioxide may have contacted prior to entry into the vessel in the mixer. The mixer may be a premixing vessel or a premixing point where the feeds meet.
Carbon dioxide in the gases vented from the vessel may be at least be partially recovered by contact with water about to enter the vessel.
The plant may be arranged to bubble the vented gases through the water in the break tank.
The plant may be also comprise an inverted bucket located in the break tank, for receiving the vented gases.
The vented gases may enter the inverted bucket through the top or bottom of the inverted bucket or in any other manner and preferably via a check valve.
The inverted bucket may have an open bottom. The inverted bucket may have an orifice formed in a closed top.
The orifice may mate with a fixed sealing member rigidly attached to the break tank.
The inverted bucket in a rest position may sit within a sleeve on footings. The sleeve and footings may further be supported by a base rigidly attached to the break tank.
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The base may be perforated.
In another arrangement the inverted bucket may- have a totally closed top and be rigidly attached to a perforated base which is itself rigidly attached to the break tank.
The inverted bucket and/or its connections may be formed of a suitable permeable material to mitigate against the accumulation of gases in the inverted bucket .
The vessel may comprise a minimum liquid level mechanism for maintaining a minimum liquid level in the vessel .
The minimum liquid level may be above the carbonated water outlet from the vessel.
The minimum liquid level mechanism may not rely on the flowrate capacity of the pump being greater than the dispenser flowrate.
The minimum liquid level mechanism may comprise an automatic drain on the outlet from the vessel.
The automatic drain may comprise a buoyant ball on a seat.
The buoyant ball may float when water in the vessel is at or above the minimum liquid level of the vessel, thereby opening the outlet from the vessel.
The minimum liquid level mechanism may comprise a level switch and a solenoid valve.
The vessel may comprise inner and outer passages.
The inner and outer passages of the vessel may be in fluid communication and may provide opposing flow paths . The inlet of the inner passage may be located at the same end of the vessel as the outlet of the outer passage.
Similarly, the outlet of inner passage may be located at the same end of the vessel as the inlet of the outer passage.
The outlet of the inner passage may be connected to the inlet of the outer passage. This connection may be
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via an automatic drain float valve. In another arrangement, the outlet of the outer passage may be connected to the inlet of the inner passage, possibly via an automatic drain float valve. The outlet passage of the vessel may be connected to the minimum liquid level mechanism.
The vessel may also comprise a tube or tubes which separate the inner and outer passages.
The passages of the vessel may be aligned substantially horizontally or vertically.
The vessel may comprise a plurality of passages.
The plurality of passages may provide opposing flow paths .
The plurality of passages may be in the form of a hose tank.
Where the vessel is a hose tank, it may comprise a plurality of passages. The plant in this arrangement may also comprise a number of chambers for accumulating gas which may or may not be located at the top of the passages.
The vessel may be arranged to receive the gas containing carbon dioxide into the top of the vessel, into either the inner or outer passage.
The vessel may be arranged to receive the water into the top of the vessel into the same passage as the gas containing carbon dioxide is received.
The vessel may be arranged to receive the gas containing carbon dioxide and the water in any suitable way. For example, the gas containing carbon dioxide may enter as bubbles below the water surface in the vessel.
The vessel may be arranged to dispense carbonated water in any suitable way such as from the top, side or bottom of the vessel.
The vessel, as a hose tank, may be arranged to receive gas containing carbon dioxide and water together or separately in any suitable way such as into the top, side or bottom of the hose tank and to dispense carbonated
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water in any suitable way such as from the top, side or bottom of the hose tank.
The passages of the hose tank may be aligned substantially horizontally or vertically. The vessel may or may not be arranged to be full of liquid when the plant is at rest and at equilibrium.
The vessel may be arranged so that in operation, most of the mixing of the water and the gas containing carbon dioxide is done in the inlet passage of the vessel. Where the water enters at the top of the vessel, it may enter as a spray or droplets or may be directed to flow over an extended surface area which may include the walls of the inner passage.
The plant may also comprise a backflow mitigation system for mitigating backflow of carbon dioxide gas and/or carbonated water from the vessel into the feed of water.
The backflow mitigation system may comprise a pressure differential valve for acting to maintain the pressure of the carbon dioxide below the pressure of the water between the vessel and the feed of water, more preferably between the vessel and the holding tank. This pressure differential could, however, be achieved in any other suitable way. The backflow mitigation system may comprise a check valve for acting against the backflow of carbonated water or carbon dioxide gas from the vessel. The check valve may be of a type required by regulatory authorities . The backflow mitigation system may also comprise a three way valve controllable by a fill signal from the vessel for acting against the backflow of carbonated water from the vessel. In this embodiment, the water level in the vessel may be controlled by a float switch acting on the three way valve . The three way valve of the backflow mitigation system may be a solenoid valve. Where it is a solenoid valve preferably it has no power applied to it in the rest
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position.
The three way valve of the backflow mitigation system may be a mechanical three way valve such as a float operated spool valve or a diaphragm valve. The three way valve of the backflow mitigation system may be located between the pressure differential valve and the vessel.
The three way valve of the backflow mitigation system may be located upstream of the check valve. The upstream side of the check valve may be in fluid communication with atmosphere in the rest position via one flow path of the three way valve of the backflow mitigation system.
Gaseous flow to atmosphere from the vessel may be prevented by the check valve of the backflow mitigation system.
The plant may also comprise a controller for controlling water flow into the vessel.
The controller may enable the relative amount of carbon dioxide to water flowing into the vessel to be adjusted.
The controller may comprise at least one restriction device in the water feed to the vessel.
The restriction device may be located downstream of the pressure differential valve.
The restriction device may comprise a throttling valve .
Where the water and gas containing carbon dioxide mix is preferably downstream of the restriction device. The gas containing carbon dioxide may enter the vessel with the water through a single conduit.
The vessel may have additional controllable two position valving on the flow paths to the vessel of the water or carbon dioxide such as a controllable on/off valve on the water flow path upstream of the mixing point or a controllable three way carbon dioxide valve with separate flow paths to the mixing point and the vessel.
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The additional controllable two position valving may be part of a multi function valve and may be activated by a water level in the vessel or a timing signal. The timing signal may be at the end of a period initiated by the dispensing valve.
The venting system may comprise a three way valve .
The three way valve of the venting system may be operable to fluidly connect the vessel to the dispenser to enable dispensing of the carbonated water from the vessel. Thus, for this variation the three way valve of the venting system may be referred to as a "three way dispensing valve" .
The three way valve of the venting system when at rest and no carbonated product is being dispensed, may be arranged so that the top of the inner passage and the top of the outer passage are in fluid communication via the chamber.
The chamber may be located above the top of the passage where the gas containing carbon dioxide enters the vessel .
The chamber may be located above the "at rest" maximum water level in the vessel.
The three way valve of the venting system for dispensing from the dispenser may be arranged to fluidly connect the top of the outer passage of the vessel to the dispenser.
In another arrangement, the three way valve of the venting system may be arranged to fluidly connect the top of the inner passage of the vessel to the dispenser.
When dispensing from the vessel, the three way valve of the venting system may be arranged to enable the chamber to be fluidly communicating to the dispenser. In doing so, this enables the accumulated gases in the chamber to be vented to atmosphere via the dispenser.
The plant may be arranged, whereby, upon dispensing from the vessel, gas containing carbon dioxide
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and water from their respective feeds are caused to enter the vessel.
The venting system may also comprise an on/off valving mechanism fluidly located between the top of the inlet passage and the three way valve of the venting system for allowing gaseous fluid communication between the top of the inlet passage of the vessel and the chamber only upon the detection of a high liquid level in the inlet passage and/or a high concentration of extraneous gases in the vessel.
The on/off valving mechanism may comprise a level control valve. The level control valve may be a float valve .
The venting system may also comprise a buffer volume between the three way dispensing valve and the dispenser.
The buffer volume may act against an unacceptable blast of pressurized gas exiting the dispenser on dispensing. The venting system may also comprise a ball float valve .
The ball float valve may be located between the three way valve of the venting system and the dispenser.
The ball float valve may have a vertical leg connected thereto.
At rest the ball float valve may be arranged to loosely close off fluid communication with the dispenser by gravity to initially allow vented gases to escape to atmosphere, preferably through the vertical leg. The ball float valve may also be arranged whereby as carbonated water flowed through, the ball float would rise to close the vertical leg and open fluid communication with the dispenser.
The venting system may comprise a well drained line from the three way valve to the dispenser. The three way valve may be above the dispenser.
The venting system may comprise flow channels
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from the top of the ball float valve to the dispenser to cater for slight leakage from the ball valve.
The venting system may comprise a multiport valve for providing the functions of the three way dispensing valve and the ball float valve discussed above. In this embodiment, a chamber which had been in fluid communication with the vapour space at the top of the inlet passage of the vessel is isolated and then vented and simultaneously or sequentially liquid product flows to the dispenser.
In a variation, where the vessel is in the form of a hose tank, the venting system may comprise an on/off valve rather than the three way valve .
The plant may comprise or may be integrable with a soft drink plant for producing and dispensing soft drinks .
The plant for producing soft drinks may comprise at least one syrup package and/or removable container and at least one manually activated three way valve. The vapour space of a syrup package or removable container may be vented by at least one set of successive pressurizing and venting steps .
According to a fourth aspect of the present invention, there is provided a method for producing and dispensing carbonated water comprising: providing a gas containing carbon dioxide; mixing the gas containing carbon dioxide with water to produce the carbonated water; filling a vessel with the water gas mixture; allowing gas from the water gas mixture in the vessel to accumulate in a chamber; dispensing carbonated water from the vessel as required through a dispenser; and venting at least a portion of the accumulated gas from the chamber in association with dispensing carbonated water from the vessel and/or in association with filling the vessel with the water gas mixture.
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The method may be carried out using the plant according to the third aspect of the present invention.
The gas containing carbon dioxide may be produced on site with the other steps of the method for producing and dispensing carbonated water. For example, the step of providing the gas containing carbon dioxide may comprise producing the carbon dioxide by combusting natural gas.
The steps of providing the gas containing carbon dioxide and mixing with the water may comprise producing and mixing the gas containing carbon dioxide in accordance with the processes described in the first aspect of the present invention.
The step of providing the gas containing carbon dioxide may comprise the provision of a pressurized cylinder of carbon dioxide.
The gas containing carbon dioxide may be close to pure carbon dioxide.
The water may be provided from a mains water supply . The method may comprise pumping the water from a feed of water using a pump, preferably to the vessel.
The feed of water may be the mains water supply.
The method may comprise holding a volume of water in a break tank between the feed of water and the pump. Preferably, the water pressure in the break tank is below the pressure of the feed of water.
The pump may have a volumetric flowrate capacity at the pressure existing in the vessel that is less, preferably much less, than the volumetric flowrate rate from the dispenser.
The volumetric capacity of the pump may be 1- 250mL/min, preferably l-50mL/min
The step of mixing may occur in the vessel.
The step of mixing may occur prior to the water and gas entering the vessel, such as in a pre-mixing vessel or at a pre-mixing point for example.
The step of mixing the gas containing carbon
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dioxide and the water may comprise inputting the water and/or gas containing carbon dioxide into the top of an inner or outer passage of the vessel.
The step of dispensing carbonated water from the vessel may comprise flowing carbonated water from the top of an outer or inner passage of the vessel.
The step of venting may occur only in association with the step of filling the vessel with the water gas mixture . The step of venting may occur only in association with the step of dispensing.
The step of venting may occur in association with both the step of dispensing and the step of filling.
The step of venting may occur immediately after the step of filling is completed.
The step of venting may occur during the step of dispensing.
The step of venting may occur immediately after the step of dispensing is completed. The step of venting may occur upon commencement of the step of filling.
The step of venting may occur immediately prior to the step of dispensing.
The step of venting may comprise flowing the carbonated water being dispensed in the step of dispensing through the chamber. By doing this, the dispensed carbonated water pushes at least some of the accumulated gas in the chamber out through the dispenser.
The step of dispensing may comprise rearranging a venting system to bring the dispenser in fluid communication with the vessel via the chamber.
The step of dispensing may comprise rearranging a three way valve .
When dispensing is not occurring, the venting system is arranged wherein the top of the inner passage of the vessel is in fluid communication with the top of the outer passage of the vessel. This may be via the chamber.
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The method may also comprise the step of operating a level control valve within the vessel to create the chamber or at least a portion of the chamber above the water level in the vessel. The level control valve may be a float valve .
The step of mixing the gas containing carbon dioxide and water may comprise inputting the gas containing carbon dioxide and water into a hose tank together or separately in any suitable way into the top, side or bottom of the hose tank.
The step of dispensing carbonated water from the hose tank may comprise flowing the water in any suitable way from the top, side or bottom of the hose tank.
The method may also comprise the step of refilling the vessel with water and/or gas containing carbon dioxide .
The step of refilling may be initiated when the step of dispensing is initiated.
The step of refilling may occur simultaneously with the step of dispensing.
The method may also comprise the step of treating the water prior to mixing it with the gas containing carbon dioxide, by for example flowing the water through a carbon filter. The method may also comprise the step of holding feed water to the vessel in a holding tank.
According to a fifth aspect of the present invention, there is provided a plant for producing and dispensing carbonated water, the plant comprising: a feed of a gas containing carbon dioxide; a feed of water; a mixer for mixing the feeds of gas containing carbon dioxide and water to produce the carbonated water; a vessel for receiving and storing the carbonated water; a dispenser which can be fluidly communicating with the vessel through which carbonated water is
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dispensed from the vessel; a chamber for accumulating gas from the gas-water mixture held in the vessel; and a pump for pumping water into the vessel, the pump having a volumetric flowrate capacity at the pressure existing in the vessel that is less than the volumetric flowrate from the dispenser.
According to a sixth aspect of the present invention, there is provided a plant for producing and dispensing carbonated water, the plant comprising: a feed of a gas containing carbon dioxide; a feed of water; a vessel for receiving towards the top of the vessel the feeds of gas containing carbon dioxide and water and storing the produced carbonated water, the vessel being in the form of a hose tank; and a dispenser which can be fluidly communicating with the vessel through which carbonated water is dispensed from the vessel.
According to a seventh aspect of the present invention, there is provided a refrigerative apparatus incorporating a plant according to the second, third, fifth or sixth aspects of the present invention.
The refrigerative apparatus may be a refrigerator or any other suitable device such as a water cooler. At least the vessel and the dispenser of the plant may be located in the door of the refrigerator.
An upper portion of the vessel of the plant may be insulated.
A lower portion of the vessel near the bottom of the refrigerative apparatus may be made of a heat conducting material for cooling the contents of the vessel .
The lower heat conducting portion of the vessel may comprise heat conducting protrusions up into the vessel.
The carbon dioxide feed in the form of a pressurized cylinder may be located inside or outside the
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refrigerative apparatus.
The refrigerative apparatus may also comprise a valve housing for housing at least most of the valves of the plant. The lower heat conducting portion of the vessel may be finned.
The lower heat conducting portion may have a pathway (s) which allows for the substantially upward flow or air so as increase heat transfer arising from natural convection.
The lower heat conducting portion may project out horizontally from the vertical projection of the vessel.
The bottom of the vessel as part of or above the lower heat conducting portion may be tapered. The break tank may also be placed in the refrigerator door, preferably proximate to the vessel.
The upper portion of the break tank may be insulated.
A lower portion of the break tank near the bottom of the refrigerative apparatus maybe made of a heat conducting material for cooling the contents of the break tank. According to an eighth aspect of the present invention, there is provided a refrigerative apparatus comprising a vessel for storing carbonated water, wherein an upper portion of the vessel is insulated and a lower portion of the vessel near the bottom of the refrigerative apparatus is made of a heat conducting material for cooling the contents of the vessel. According to a ninth aspect of the present invention, there is provided a rotary pinch valve comprising a rotor, a stator, at least one rigid backing member and a plurality of movable members suitable for a plurality of flexible tubes. The rotor may comprise a single essentially circular cam disk.
The rotor may comprise a plurality of essentially
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circular cam disks separated from each other by cam spacer disk(s) and arranged as an essentially cylindrical whole.
The essentially cylindrical whole of the rotor may comprise separate laminar cam disks and spacer disks held together by fastener (s) or comprise an essentially continuous piece of rigid material.
The stator may comprise at least one stator pinch disk.
The stator may comprise a plurality of stator pinch disks separated from one another by a stator spacer disk(s) and arranged into an aligned whole.
The aligned whole of the stator may comprise separate laminar disks held together by fastener (s) or comprise an essentially continuous piece of rigid material.
A cam disk and its matching stator pinch disk may be in the same pinch plane.
A cam spacer disk and a stator spacer disk may be in the same plane. The stator may be essentially cylindrical.
The stator may be truncated.
The stator may comprise at least one removable end plate so as to allow loading of the essentially cylindrical rotor. The rotor and stator may have a means for being maintained in proper relative axial position.
The rotor when loaded may be maintained in proper axial position by the removable end plate.
At least one pinch slot may be located in a stator pinch disk.
The stator may have matching alignment holes at axially opposite ends of the stator for positioning the plurality of flexible tubes.
The alignment holes of the stator may be separated by alignment gaps.
A removable end plate may have alignment holes for positioning the flexible tubes separated by alignment
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gaps .
The plurality of flexible tubes may be aligned along the stator parallel to the axis of the rotary pinch valve . A particular flexible tube may be aligned to pass over at least one pinch slot.
A pinch slot may comprise at least one spring compression base.
Pinch slots may be staggered around the circumference of the stator as well as along its axial length.
The at least one rigid backing member may comprise a single rigid piece suitable as a backing member for the plurality of flexible tubes. The single rigid piece may be removable from or rotatable about the stator.
The at least one rigid backing member may comprise a plurality of individual rigid backing members, one for each pinch slot and its associated particular flexible tube.
An individual rigid backing member may be positioned over a particular pinch slot.
A rigid backing member may be rigidly attached to the stator. An individual rigid backing member may be rigidly attached to the stator by a strut (s).
An individual rigid backing member may be rigidly attached to the stator by radial struts or substantially radial struts. A particular individual rigid backing member may be removable from the radial struts or rotatable around them, so as to facilitate loading new flexible tubing and/or movable members .
A movable member may comprise a curved surface for mating with a cam disk and a pinching surface for pinching a particular flexible tube.
A movable member may comprise lateral
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protrusions .
A movable member may comprise a pinching surface with rounded edges to avoid cutting the flexible tube.
A movable member may be positioned in any pinch slot of the stator
The rotary pinch valve may comprise a spring mechanism for acting on any particular movable member so as to ensure appropriate positioning of that particular movable member relative to its particular cam disk. The spring mechanism may comprise a pair of springs acting on a spring compression base(s) associated with a pinch slot of the stator and lateral protrusions associated with a movable member.
The spring mechanism may comprise at least one short elastically deformable sleeve more resilient than a particular flexible tube which fits over a particular flexible tube in the vicinity of the pinch slot
The stator may comprise aligners to prevent lateral movement of any particular flexible tube and thereby allow the particular flexible tube to be pinched by a compact sized movable member the width of which is essentially the width of a pinched flexible tube.
Aligners for a particular flexible tube may be placed upstream or downstream of the pinch slot associated with a particular flexible tube and preferably at a distance where the particular flexible tube always exhibits an unpinched diameter and preferably as close to the pinch slot as possible.
Aligners may be incorporated into a stator spacer disk.
Aligners and radial or substantially radial struts for any particular flexible tube may be placed within a passage which is in axial alignment with an alignment gap in the end plate. Radial or substantially radial struts associated with an individual rigid backing member may encompass at least three flexible tubes.
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A pinched flexible tube may be axially adjacent to two adjacent flexible tubes that are not exhibiting a pinched diameter within that same pinch plane.
A pinch slot may extend laterally within the pinch plane across an axial passage associated with its associated flexible tube and also across both adjoining axial passages associated with the aligners of that flexible tube, preferably fully across both adjoining axial passages associated with the aligners of that flexible tube.
A flexible tube when pinched may spread its width into the axially aligned passage occupied by its aligners, preferably fully into the axially aligned passage occupied by its aligners. Alignment gaps may be sized such that the pinched flexible tube and/or its associated extended movable member when in the pinched condition almost touch the unpinched flexible tubes either side of it within the same pinch plane. Any of the movable members or springs or flexible tubes may be loaded into the rotary pinch valve from an external position.
Movable members and/or springs may be loaded into the rotary pinch valve from an external position after the rotor has been placed in the stator and preferably with the end plate fixed.
The stator may comprise a plurality of indentations upstream or downstream of a pinch slot for the purpose of externally loading a plurality of movable members into their pinch slots.
The shape of the indentations may approximate the shape of the bottom of a movable member.
The stator may comprise a plurality of removable indentation filling pieces for filling the indentations after the plurality of movable members have been loaded into their pinch slots.
Movable members may be loaded into the stator
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from an external position by placing the movable member in an indentation in the stator and sliding the movable member axially and under the individual rigid backing member so that the pinching surface of the movable member is substantially flush with the pinching surface of the individual rigid backing member and then with the movable member being loaded into the pinch slot.
Where springs within a pinch slot are used the movable member when slid under the individual rigid backing member so as to be substantially flush with it may have its lateral protrusions fit just under the spring compression base(s) .
Where no springs within a pinch slot are used a spring compression base (s) is not necessary but the lateral protrusions of the movable member may be maintained for alignment purposes and the movable member may be advanced into the stator by the distance taken by the flexible tube.
Where springs within a pinch slot are used the springs may be then added to act on the movable member and the indentation filled with a solid indentation filling piece of material so as to act as a backing surface for maintaining the springs and/or the movable member in correct alignment. Movable members with or without their associated springs may be loaded into the stator from an external position by removal from the stator or rotation within the pinch plane or otherwise of a latching piece comprised of an individual rigid backing member, radial or substantially radial strut (s) and spring compression base(s) and subsequently latching the latching piece to the stator.
An individual rigid backing member as an individual piece may be removable from or rotatable about its associated radial or substantially radial strut (s)
The stator may be assembled about the rotor from a number a laminar stator pinch disks alternating with
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laminar stator spacer disks and with the movable members with or without associated springs, loaded with each appropriate laminar stator pinch disk.
At least one pinch valve may be located along the axial length of a flexible tube.
The rotary pinch valve may be programmable by providing a means to rotate and fix any cam disk relative to another cam disk.
A means to rotate any cam disk relative to another cam disk may comprise laminar cam disks and laminar cam spacer disks being detachable and having matching bolt holes or male and female accommodations at regular angular intervals.
The plurality of flexible tubes may be of different diameter.
A change of valve state as from open to closed and closed to open is abrupt, as from five to fifteen rotational degrees of the rotor.
The rotor may rotate within or about the stator with a close clearance.
The rotor may be driven by a rotating mechanism such as a geared electric motor or stepper motor.
Any of the cam disks may act on a particular movable member positioned within a pinch slot in the same pinch plane of the stator so as pinch a particular flexible tube against a rigid backing member so as to open and close the particular flexible tube in a desired manner .
Brief Description of the Drawings
Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
Figure 1 is a schematic view of a plant for producing carbonated water;
Figure 2 is a schematic view of a part of the plant of Figure 1 during a sorption step of a method for
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producing carbonated water using the plant of Figure 1; Figure 3 is a schematic view of a part of the plant of Figure 1 during a pressure release step of the method for producing carbonated water using the plant of Figure 1;
Figure 4 is a schematic view of a part of the plant of Figure 1 during a vacuum purge step of the method for producing carbonated water using the plant of Figure 1; Figure 5 is a schematic view of a part of the plant of Figure 1 during a desorption step of the method for producing carbonated water using the plant of Figure 1;
Figure 6 is a schematic view of a plant according to another embodiment of the present invention for producing carbonated water;
Figure 7 is a schematic view of a part of the plant of Figure 6 during a sorption step and a water pressurisation step of a method for producing carbonated water using the plant of Figure 6;
Figure 8 is a schematic view of a part of the plant of Figure 6 during the sorption step and a fluid displacement vessel filling step of the method for producing carbonated water using the plant of Figure 6; Figure 9 is a schematic view of a part of the plant of Figure 6 during the sorption step and a venting step of the method for producing carbonated water using the plant of Figure 6;
Figure 10 is a schematic view of a part of the plant of Figure 6 during a pressure release step of the method for producing carbonated water using the plant of Figure 6 ;
Figure 11 is a schematic view of a part of the plant of Figure 6 during a vacuum purge step of the method for producing carbonated water using the plant of Figure 6;
Figure 12 is a schematic view of a part of the
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plant of Figure 6 during a desorption step of the method for producing carbonated water using the plant of Figure 6;
Figure 13 is a diagrammatic view of a pump of the plant of Figure 6 according to an embodiment of the present invention;
Figure 14 is a diagrammatic view of a combined compressor and pump for the plant of Figure 6 according to another embodiment of the present invention; Figure 15 is a schematic view of a plant according to a further embodiment of the present invention for producing carbonated water;
Figure 16 is a schematic view of a plant according to yet another embodiment of the present invention for producing carbonated water;
Figure 17 is a schematic view of a soft drink plant for the production and dispensing of flavoured soft drinks;
Figure 18 is an electric circuit for use in controlling operation of the plant of Figure 1;
Figure 19 is a schematic view of a plant for producing and dispensing carbonated water according to an embodiment of the present invention;
Figure 20 is a schematic view of a plant for producing and dispensing carbonated water according to another embodiment of the present invention;
Figure 21 is a schematic view of a plant for producing and dispensing carbonated water according to another embodiment of the present invention; Figure 22 is a schematic view of a plant for producing and dispensing carbonated water according to yet another embodiment of the present invention; and
Figures 23 and 24 are diagrammatic views of the plant according to embodiments of the present invention incorporated into a refrigerator.
Figure 25 is a schematic view of a plant for producing and dispensing carbonated water according to
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another embodiment of the present invention;
Figure 26 is a schematic view of a plant for producing and dispensing carbonated water according to another embodiment of the present invention; Figure 27 is a schematic view of a plant for producing and dispensing carbonated water according to another embodiment of the present invention;
Figure 28 is a schematic view of a plant for producing and dispensing carbonated water according to another embodiment of the present invention;
Figure 29 is a schematic view of a plant for producing and dispensing carbonated water according to another embodiment of the present invention;
Figure 30 is a schematic view of a portion of a plant for recovering carbon dioxide from vented gases according to an embodiment of the present invention;
Figure 31 is a schematic view of a portion of a plant for recovering carbon dioxide from vented gases according to an embodiment of the present invention; Figure 32 is a schematic view of a further portion of a plant for recovering carbon dioxide from vented gases according to a further embodiment of the present invention;
Figure 33 is a schematic view of a further portion of a plant for recovering carbon dioxide from vented gases according to a further embodiment of the present invention;
Figures 34 and 35 are side and top views of a vessel of the plant according to embodiments of the present invention;
Figure 36 is an overall view of the rotary pinch valve but showing the apparatus to pinch but one flexible tube;
Figure 37 is an exploded view of the curved surface of the rotary pinch valve stator indicting pinch slots staggered around the circumference as well along the axial length of the stator;
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Figure 38 is an overall view of the essentially cylindrical rotor comprised of alternating cam disks and cam spacer disks;
Figure 39 shows an example of the cross section of two possible cam disks of the rotor;
Figure 40 is a view through a particular pinch plane outlining the pinch mechanism;
Figure 41 is a view of a cross section of the stator showing aligners for flexible tube positioning; Figure 42 is a view of a movable member ready to be loaded via an indentation into a pinch slot of the stator in association with springs;
Figure 43 is a view of a movable member loaded via an indentation into a pinch slot of the stator in association with springs;
Figure 44 is a view of a movable member ready to be loaded via an indentation into a pinch slot of the stator with no pinch slot springs;
Figure 45 is a view of a movable member loaded via an indentation into a pinch slot of the stator with no pinch slot springs;
Figure 46 is a partially exploded view of a rigid backing member as an individual piece rotatable about a modified radial strut; and Figure 47 is a view of a particular cam disk of the rotor comprising bolt holes so as to allow programming of the rotary pinch valve .
Detailed Description of Embodiments Embodiments of the present invention relate to a method for producing carbonated water which comprises the general steps of manufacturing a gas containing carbon dioxide on site and in situ mixing the carbon dioxide with water to produce carbonated water. This advantageously means that carbon dioxide does not need to be liquefied and transported in pressure vessels to another site for use or for rebottling into smaller cylinders for further
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distribution, all of which would add to the cost. The method according to embodiments of the present invention further does away with the need to use carbon dioxide cylinders in refrigerator applications, which is also a significant advantage both in terms of ease of use and operational costs.
The gas containing carbon dioxide may be manufactured by any suitable physical or chemical methods such as extraction from a gas such as contaminated air or as a product (waste or desired) from a chemical reaction for example. Common chemical reactions which produce carbon dioxide include fermentation, steam reformation of hydrocarbons and combustion reactions .
Before mixing the manufactured carbon dioxide with the water to produce carbonated water, the gas containing carbon dioxide will usually require purification. This may occur by any suitable mechanism, such as filtration, swing sorption (such as under a thermal, pressure, microwave or electrical swing (such as that disclosed in US 5972077) or any combination thereof) , scrubbing or de-misting for example. The type of purification mechanism may be dependent on how the gas containing carbon dioxide was derived and thus what impurities it has. The carbon dioxide may also require pressurisation, in particular after the step of purification. However, in some embodiments the carbon dioxide may be at sufficient pressure after purification (and hence not require further pressurisation) or may be pressurised during purification. Similarly, the water which the carbon dioxide is mixed with may require pressurisation. This may or may not occur simultaneously with the step of mixing the carbon dioxide with the water. The resulting carbonated water, produced according to the method of this invention has a conventionally acceptable concentration of carbon dioxide of approximately four volumes (at atmospheric temperature
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and pressure) per volume of water. The carbonated water produced is stored, ready for use, in a pressurised vessel, and generally chilled to a temperature of approximately 4 0 C. Referring now to Figures 1 to 5, a particular application for the method according to embodiments of the invention is in relation to a refrigerator. Figure 1 shows a plant 100 for producing carbonated water according to an embodiment of the present invention which is particularly suitable for use in relation to a refrigerator.
In the plant 100, the gas containing carbon dioxide is manufactured by combusting a hydrocarbon fuel, preferably natural gas which can be readily drawn from the reticulated supply in most urban and commercial areas. The water which the carbon dioxide manufactured in the plant 100 is mixed with, is typically sourced from mains water. Thus, the plant 100 is suitable for installation in relation to a refrigerator because its two major input streams can be supplied by connecting the plant 100 to the reticulated gas and water supplies available in many homes and businesses. Such water may undergo treatment such as by a carbon filter or an exchange resin before introduction to the plant 100.
The plant 100 comprises a combustion unit 101 having cooling jackets 102, 103, a first liquid ring compressor stage 104, a second liquid ring compressor stage 105, a sorber/desorber 106, a cool water reservoir 107 and a product drawdown vessel 108.
In general, the combustion unit 101 is for combusting natural gas to manufacture carbon dioxide and comprises a burner 117 firing into a firebox 118 (which is insulated). The jackets 102, 103 are arranged relative to the firebox 118 so as to cool the firebox 118. The first jacket 102 is also for steam generation, the purpose of which will become apparent further on in the specification.
The sorber/desorber 106 is for purifying the
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carbon dioxide by a swing sorption mechanism, preferably by temperature and pressure swing sorption. The sorbent in the sorber/desorber 106 is a non-toxic sorbent, so that the plant 100 may be safely used in a refrigerator (in particular in a domestic refrigerator) without any risk of toxic contamination of the carbonated water product . The sorbent may be an aqueous based liquid sorbent, however for the plant 100 shown in Figures 1-5, it is preferably solid and substantially non-miscible with water. This is because a solid sorbent is less likely to cause toxic contamination of the produced carbonated water by spillage or leakage for example. Furthermore, use of a solid sorbent avoids the further problem which may occur if using a liquid sorbent of possible rupture of the pressurised plant equipment associated with the liquid sorbent. Such ruptures could lead to leaks of toxic chemicals. In addition, the solid sorbent provides for easier control of the water balance in the sorber/desorber 106, because the water readily disengages from the solid sorbent. However, use of liquid sorbent in the sorber/desorber 106 is possible in the present invention.
In selecting an appropriate sorbent, a balance needs to be found between the sorption capacity of the sorbent, its selectivity, stability and vapour pressure. Furthermore, the presence of water, whether by humidity or liquid condensation, can impinge differently on different sorbents .
One suitable sorbent with good selectivity and stability in an environment with water condensation is a weak base anion exchange resin such as Rohm and Haas IRA
96 or Dowex Marathon WBA-2, for example. These particular weak base anion exchange resins are macroporous and have a polystyrene backbone and tertiary amine functionality (in the free base form) . However, any suitable sorbent may be used.
Molecular sieves can be utilised, but water, even as humidity, may be competitive with carbon dioxide for
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sorption. Porous substrates with amine function compounds "immobilised" on them by chemical or physical means (for example as described in US 5876488) can have superior sorption capacities, but condensation may leach such amine compounds from the substrate. Other sorbents may be subject to hydrolysis.
For sorbents affected by water in such a way, gaseous feed to the sorber/desorber 106 will preferably need to be dewatered. This may effectively be achieved through refrigeration of compressed gaseous feed, prior to entering the sorber/desorber 106 but disadvantageously involves another processing unit and associated space.
The first and second liquid ring compressor stages 104, 105 are for providing the required pumping and compression in the plant 100. Advantageously, because the liquid ring compressor stages 104, 105 simultaneously handle liquid and gas working fluids, they can potentially each act as a compressor and a pump. Furthermore, the liquid ring compressor stages 104, 105 are compact, rotary, low maintenance, quiet and can perform a scrubbing function (and therefore assist in the removal of impurities from the carbon dioxide) . It is to be understood that in other embodiments not shown in the Figures, that the plant 100 may comprise more than two liquid ring compressor stages.
In the embodiment shown in Figures 1 to 5, the first liquid ring compressor stage 104 comprises a first top level float separator 109, a first liquid ring compressor 110 and a first separator 111. The second liquid ring compressor stage 105 comprises a second top level float separator 112, a second liquid ring compressor 113, a bottom level float separator 114 and a second separator 115. However, in other embodiments, the first and second liquid ring compressor stages 104, 105 may each comprise more than one individual compressor. Individual compressors of the plant 100 may be driven by the same or separate motors . The purpose of the various components of
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the liquid ring compressor stages 104, 105 will become apparent from the description of the operation of the plant 100 below.
The cool water reservoir 107 is for providing a buffer between the mains water supply and any carbon dioxide or pressurised water in the plant 100 so as to mitigate against backflow and contamination of the mains water. The cool water reservoir 107 has a float valve 116 which is connected to the mains water supply, for maintaining the water level in the cool water reservoir
107. The cool water reservoir 107 may thus also act as an inventory for the water in the plant 100.
The product drawdown vessel 108 is for storing the carbonated water produced by the plant 100 and for consequently dispensing the carbonated water therefrom. The product drawdown vessel 108 is designed to have a significant freeboard of gaseous space to act as a propellant for dispensing even when the product drawdown vessel 108 is nominally full. This means that it is unnecessary for the plant 100 to have a dispensing pump. The product drawdown vessel 108 has an automatic drain float valve 119 for preventing the carbonated water from being dispensed from the product drawdown vessel 108 when the carbonated water is at a low level in the vessel 108. This prevents the product drawdown vessel 108 from emptying completely of carbonated water which could result in air ingress to the product drawdown vessel 108. Such air ingress is undesirable as it will interfere with the carbonation process on subsequent cycles. The plant 100 operates according to a batch process, involving the following four general operational steps :
Sorption (Figure 2) - Sorption of carbon dioxide from compressed combustion gases by a regenerable sorbent under the influence of raised pressure and preferably also cooling Pressure Release (Figure 3) - Let down of the sorbent
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bed in the sorber/desorber 106 to atmospheric pressure Vacuum Purge (Figure 4) - Depletion of a substantial amount of the extraneous gases from the sorbent bed in the sorber/desorber 106 to atmosphere. Desorption/Carbonation (Figure 5) - Desorption of carbon dioxide under the influence of lowered pressure and preferably also heating followed by compression of the carbon dioxide and mixing with water to produce carbonated water. The plant 100 also comprises a valve system 120 for directing the fluid flow during the operation of the plant 100 at the different operation steps. The valve system 120 comprises a plurality of valves (marked 1-17) .
The valve system 120 may comprise a rotary valve, preferably a rotary pinch valve. It may be driven by a speed reduction unit off the compressor motor. In other embodiments, the valve system 120 comprises a three position valve, preferably a pinch or spool valve relying on the pressures of vacuum, atmospheric pressure and sorber/desorber relief pressure for positioning.
Referring specifically now to Figure 2, in conjunction with Figure 1, the significant components of the plant 100 involved in the sorption step of the operation of the plant 100 are shown. A feed of natural gas 121, comprising mostly methane, is provided to the burner 117 of the combustion unit 101 where it is combusted with air according to the following reaction:
CH 4 + 2.4O 2 + 9N 2 -> CO 2 + 2H 2 O + 9N 2 + 0.4O 2 + heat
The natural gas is preferably combusted in approximately 20% excess air to produce a stream of approximately 10% carbon dioxide (on a water free basis) . This stream exits the firebox 118 and is cooled as it passes through heat exchange tubing 122.
The burner 117 may be any suitable burner that
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effectively mixes air and natural gas without substantial extraneous air ingress. The burner 117 may be an atmospheric burner or be contained in a firebox which is exposed to atmosphere by one or more flame arrestors. The burner 117 may be also totally enclosed in a firebox and rely on induced draft. In a particular embodiment, the burner 117 is a high velocity burner. The burner has a small capacity of up to and around 1 MJ/hr, which is commensurate with the flow rate of combustion gases to the plant 100. The burner 117 could be operated in several different ways, including the burner 117 being on continuously, ignition of the burner 117 by a continuous pilot flame or ignition of the burner 117 on start-up of operation of the plant 100. Should a pilot flame smaller than the process flame of the burner be utilised, the process flame could reach its full process size via appropriate poppet valving in the valve system 120.
The burner 117 may also comprise a flame safeguard device. The flame safeguard device is for shutting off the natural gas supply should the burner flame be extinguished, thereby preventing the possible dangerous accumulation of a combustible gas. The flame safeguard device may comprise for example a thermoelectric valve or a solenoid valve. In the embodiment where the flame safeguard device comprises a solenoid valve, it is controlled by a flame switch that may be incorporated into an integrated flame sensing electronic module.
Thus, with the flame safeguard device, the process of igniting the burner 117 involves opening the flame safeguard device in the form of a solenoid valve or thermo-electric valve for a short period of time, in conjunction with a source of ignition and starting a timing device. Successful ignition of the burner 117 within a "trial for ignition" designed time period results in the valve of the flame safeguard device staying open, whereas unsuccessful ignition results in the valve
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closing. The burner 117 may also comprise an alarm indication for signalling an unsuccessful ignition as this may be indicative that the burner 117 is not functioning properly. In the case of a thermoelectric valve it is possible to use the intrinsic capabilities of the plant 100 to open the thermoelectric valve and thereby ignite the flame. For example, the thermoelectric valve may be opened during the trial for ignition period by depressing the mechanical plunger of the thermoelectric valve utilising either start up compression gases or a cam operating off a rotating member associated with (a motor of) the plant 100.
However, in both instances it is necessary to ensure that should the motor stop in the trial for ignition period that no undue combustible gas escapes to atmosphere. Where compression gases are utilised to open the thermoelectric valve this may involve a permeable diaphragm actuator which gradually loses pressure on stoppage of the motor thereby closing the thermoelectric valve .
Where a rotating cam is utilised to open the thermoelectric valve, a reservoir of gas may be positioned between the thermoelectric valve gas inlet and a gas valve in the valving system 120. This gas valve would be open at rest thereby pressurising the reservoir of gas to line pressure. However, it would close on start up of the plant 100 whereafter the cam would depress the plunger of the thermoelectric valve to the open position allowing combustible gas from the reservoir to be ignited.
The reservoir of gas would have sufficient capacity given the burning rate to maintain a flame for the duration of the trial for ignition period together with the time for the gas valve in the valving system 120 to reopen thereby maintaining a flame caused by a successful ignition.
However, should the motor stop during the trial
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for ignition with the cam maintaining the thermoelectric valve in the open position, the reservoir of gas will be depleted thereby extinguishing the flame. The closed gas valve of the valving system 120 would prevent combustible gas flowing to atmosphere.
In addition to an ignition device, the burner may also comprise a re-ignition device which acts to re-ignite the flame before the flame safeguard valve closes. It is also noted that should the burner flame fail and unsuccessful re-ignition occur, that it may be preferable that once started, the operation of a cycle of the plant 100 goes to completion. It may also be preferable that the flame safeguard valve close should there be a power cut. In another embodiment, any of the combustion unit, burner, flame safeguard and ignition and re-ignition devices may also be part of another appliance such as a gas stove or a gas hot water system.
On start up, the first liquid ring compressor stage 104 acts as a compressor of the combustion products. Valve 1 is opened and valve 2 closed to allow the cooled combustion products to flow into the first top float separator 109 and then into the suction of the first liquid ring compressor 110. The first liquid ring compressor 110 compresses the gas containing carbon dioxide which then exits the first liquid ring compressor 110 into the first separator 111.
The liquid in the first liquid ring compressor
110 is the condensate water formed in the combustion reaction. Because of the nature of a liquid ring compressor some liquid is ejected from the compressor 110 into the first separator 111. The function of the first separator 111 is to therefore capture at least some of this ejected liquid and return it to the suction side of the first liquid ring compressor 110 via the first top level float separator 109. This is preferably done with cooling of the ejected liquid between the first separator
111 and the first top level float separator 109. This may
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be done by flowing it through heat exchange tubing in the cool water reservoir 107 (as shown in Figure 2) . This helps in ejecting at least some of the heat of compression from the first liquid ring compressor 110. This continues for the rest of the operational cycle of the plant 100 and as a result enhances the performance of the first liquid ring compressor 110 over the entire cycle. In another embodiment, it may be desirable, during sorption only, to direct this flow to an alternate source of cooling such as air cooling either within the refrigeration space or outside it. This avoids placing a heat load on the cool water reservoir and gives flexibility in achieving proper humidity from the first separator 111.
A high level float valve 123 in the first top level float separator 109 prevents the float separator 109 from over flowing with liquid by closing off the ejected liquid inlet from the first separator 111 when the liquid level becomes to high in the first top level float separator 109. It is noted, in this regard that the first top level float separator 109 and the first separator 111 are designed to have a combined volume which is sufficient to hold the volume of condensate produced during a single operational cycle of the plant 100.
The compressed gas containing carbon dioxide exits the first separator 111 and flows via valve 3 (with valves 2, 13 and 14 closed) into the sorber/desorber 106 for sorption of the carbon dioxide in the sorbent under raised pressure. It is noted that if the sorbent is a weak base anion exchanger resin (as described above) then it requires a moist environment in order to function most efficiently. This is suitably provided by the humidity in the gas stream exiting the first separator 111 but in another embodiment may be provided by process condensate exiting the same first separator 111. The gas, substantially depleted of carbon dioxide, exits the sorber/desorber 106 through a relief valve 124 and thence to atmosphere via the second jacket
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103 of the combustion unit 101 in order to cool the firebox 118. Flow through the second jacket 103 of the combustion unit 101 also serves to muffle the noise of the escaping gases. In other embodiments, a separate muffling device may be required. The relief valve 124 is located towards the top of the sorber/desorber 106 so as to act against possible particulate contamination of the relief valve 124 from the friable sorbent resin. The relief valve 124 preferably has a design relief pressure of approximately 50 to 75psig.
During this sorption stage, the second liquid ring compressor stage 105 acts as a cooling liquid pump to cool the sorber/desorber 106. Sorption of the carbon dioxide is enhanced by this cooling. Water is drawn from the cool water reservoir 107 via valve 5 and the second top level float separator 112 into the second liquid ring compressor 113, which then pumps the water via valve 7 through heat exchanger tubes in the sorber/desorber 106. The water is returned to the cool water reservoir 107 from the sorber/desorber 106 via valve 12. Although it would be possible to use the liquid discharged through the outlet of the second liquid ring compressor 113 to provide this cooling fluid flow, it is preferable (as shown in Figure 1) to derive this flow as a take-off on the casing of the second liquid ring compressor 113 (as indicated by US 3973879) . This is because this take-off flow can be designed to be greater than the liquid discharge flow, thereby creating a greater cooling capacity. The use of the second liquid ring compressor 113 to pump cooling fluid through the sorber/desorber 106 enables the sorber/desorber 106 to be positioned outside of the refrigeration space of the refrigerator which the plant 100 is associated with. Although the sorber/desorber 106 could be placed inside the refrigeration space, in which case cooling during sorption would be provided by the refrigerator and cooling water from the cool water
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reservoir 107 would not be required, the cooling caused by the refrigerator would act against the heating of the sorber/desorber 106 carried out during desorption. Another advantage of positioning the sorber/desorber 106 outside the refrigeration space of the refrigerator is that it will protect the sorbent from damage due to inadvertent freezing, which could be caused by improper refrigerator conditions .
At the start of the sorption step, it may take a little time to build-up the required pressure in the sorber/desorber 106 and thus have relief gases passing through the second jacket 103 to cool the firebox 118. This may have a negative impact, due to the high temperature, on any polymer take offs from the firebox (such as silicone or PTFE, eg) . Therefore, in an embodiment (as shown in Figure 2) , some of the cooling water exiting the heat exchanger tubes of the sorber/desorber 106 may be pumped, via valve 6, into the first jacket 102 to prevent overheating of the firebox 118 at start-up. Excess water flow returns to the cool water reservoir 107 via valve 10. As soon as the first jacket 102 has been filled, it should be immediately drained (by opening valve 17) to the cool water reservoir 107. This flow of cooling water through the first jacket 102 also ensures that scale does not build up on the surface of the jacket, particularly where mains water is being used.
However, in an alternative embodiment, at the start of the sorption step, the liquid contents of the heat exchanger tubing in the sorber/desorber 106 which have been left there from previous operational cycles of the plant 100, are purged into the first jacket 102 using start-up purge gases from the liquid ring compressors 110, 113 (followed by immediate drainage) to provide initial cooling of the firebox 118. Referring now to Figure 3 (in conjunction with
Figure 1) , the next step in the operation of the plant 100 is pressure release . The sorber/desorber 106 is isolated
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from gaseous feed by the closure of valve 1. The sorber/desorber 106 is subsequently let down to atmospheric pressure by opening valve 9, which directs gas through the second jacket 103 (to cool the firebox 118) .
The outlet from the sorber/desorber 106 through which pressure release gas is directed is preferably located slightly above the bottom of the sorber/desorber 106 so as to leave a well of condensate water at the bottom of the sorber/desorber 106. The well of condensate is for acting against the ion exchange resin drying out when not in use with consequent loss in capacity.
Referring now to Figure 4 (in conjunction with Figure 1) , the next step in the operation of the plant 100 is vacuum purge. The vacuum purge step extracts a substantial amount of the extraneous gases from the sorber/desorber 106 which comprises mostly oxygen and nitrogen, particularly nitrogen by applying a low pressure on the sorber/desorber 106 using the liquid ring compressor stages 104, 105. The reason for doing this is to remove as much of the nitrogen as possible, as it interferes with the subsequent carbonation process.
The vacuum purge occurs by opening valves 2 and 14 with valve 1 closed and vacuuming the gas out of the sorber/desorber 106 through the first liquid ring compressor stage 104 and then through the second liquid ring compressor stage 105. An optional recycle of the gas exiting the first separator 111 of the first liquid ring compressor stage 104 to the gas flow into the first top float separator 109 is provided through valve 3. A similar optional recycle may be provided across the second liquid ring compressor stage 105 through valve 15. This recycling can improve the sensitivity of the valve system 120 (which may be slow moving) in regard to the appropriate vacuum from which to switch from vacuum purge to desorption. It can also act to increase the recovery of carbon dioxide from the gas being vacuum purged by dissolution of carbon
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dioxide in the water within the compressors (nitrogen gas is relatively insoluble in water in relation to carbon dioxide) .
The vacuum purged gases may be subsequently purged directly to atmosphere. However, in an embodiment they are purged from the top of the bottom level float separator 114 via valve 11 through the heat exchanger tubes of the sorber/desorber 106 so as to push the residual liquid in the heat exchanger tubes (from the sorption stage) up into the first jacket 102 of the combustion unit 101 (through valve 6) in preparation for the desorption stage. The purged gases and any overflow of water from the first jacket 102 is directed back to the cool water reservoir 107 through valve 10. In another embodiment, the second liquid compressor stage 105 acting as a pump, pumps water into the jacket 102 in preparation for desorption. This particular embodiment using the second compressor stage 105 as a pump, if performed slightly earlier in the cycle could also be used to cool the combustion unit 101 immediately after it ceased to be cooled by relief gases from the sorber/desorber 106.
In another embodiment, so as to recover a greater quantity of carbon dioxide in the water within compressor stages 104,105, the vacuum purge gases first flow under pressure through a relief valve on the top of bottom level float separator 114 and then via valve 11 to atmosphere as above.
In a similar embodiment not shown in the figures, it is also possible to utilise just the first compressor stage to enact the vacuum purge, with a relief valve on the first separator 111 and with valve 14 closed. It is also possible to bubble vacuum purge gases through water in the cool water reservoir 107 so as to recover carbon dioxide values from the vacuum purge gases.
In yet another embodiment to further recover carbon dioxide values from the vacuum purge gases not
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shown in the figures, the vacuum purge gases are directed through a second sorber/desorber . This second sorber/desorber is smaller than the first mentioned sorber/desorber 106 but contains a suitable similar sorbent . The secondary sorber/desorber is equipped with a relief valve through which the vacuum purge gases are directed from the sorber/desorber 106 to atmosphere. It is possible for the relief valve to be "shared" between the two sorber/desorbers by appropriate valving in the valving system 120. The second sorber/desorber may or may not be exposed to a pressure release step. It is not necessary to expose the second sorber/desorber to a vacuum purge step. In a preferred embodiment, the second sorber/desorber has no internal cooling/heating tubing similar to that in sorber/desorber 106, though it may have such heat exchange tubing. However, it may be heated and cooled by physical contact with sorber/desorber 106. By slowly enacting the vacuum purge on the sorber/desorber 106, as indicated elsewhere herein, carbon dioxide values are recovered in the second sorber/desorber with nitrogen enriched gases flowing to atmosphere through the relief valve on the second sorber/desorber. These relief gases may be similarly utilised for further uses such as for pumping water into the jacket 102 of the firebox as explained elsewhere herein. A pressure release step is then enacted on the second sorber/desorber. Thereafter at an appropriate time in the desorption step, vacuum is applied equally to both sorber/desorbers in parallel so as to produce product gas . It is important that the second sorber/desorber, if it uses a similar ion exchange resin to the sorber/desorber 106 also does not dry out. This may be achieved by directing pressure release gases from the sorber/desorber 106 through the second sorber/desorber to atmosphere, preferably so as to leave a well of condensate in the bottom of the second sorber/desorber.
In designing aspects of the vacuum purge, in
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particular the low pressure reached in the sorber/desorber 106 and the time taken to vacuum purge, a balance must be found between expelling nitrogen and losing carbon dioxide (which will begin to desorb at reduced pressures) . An optimum low pressure on the sorber/desorber 106 will exist for the plant 100 at which operation of the plant should switch from the vacuum purge step to the desorption step (described below) . In a variation not shown in the Figures, the plant 100 may comprise a vacuum valve to effect this change from vacuum purge to desorption. The vacuum valve may take a number of forms . In one embodiment, the vacuum valve may be a vacuum actuated three way valve with the actuator being exposed to the compressor stage 104 suction but with the three way valve placed on the compressor stage 104 or 105 discharge so as to switch compressor discharge flow from vacuum purge to desorption at a designed low pressure in the sorber/desorber 106. In another form, the vacuum valve may comprise a pair of parallel tubes each valved separately in the valve system apparatus 120, and each feeding into the suction (inlet) side of first liquid ring compressor stage 104. Additionally, one of these lines is designed to close at the designed low pressure by an additional valve in the line. This valve may be a check valve with an appropriately set cracking pressure or a collapsible tube set to collapse at the designed low pressure. Initially, vacuum purge flow is through the dual valved suction line with the parallel suction line closed. After the designed low pressure has been reached, valve 11 closes and then valve 4 opens, whereafter the parallel suction line is opened by a valve in the valving system 120 allowing the flow of desorption gases.
In another embodiment, the vacuum purge step and pressure release step occur in the same flow scheme, with the pressure release gases flowing to atmosphere via either or both compressor stages 104, 105, followed immediately by the vacuum purge gases along the same flow
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path. This embodiment minimises valve openings and closures, but may cause an undue rush of gases through the compressor during pressure release.
Referring now to Figure 5, in conjunction with Figure 1, the next step in the operation of the plant 100 is desorption of the carbon dioxide from the sorber/desorber 106 followed by compression of the carbon dioxide and mixing with water (carbonation) .
Valves 2 and 14 remain open and the first and second liquid ring compressor stages 104, 105 continue to apply a vacuum on the sorber/desorber 106. The reduced pressure applied to the sorber/desorber 106 causes the carbon dioxide to desorb from the sorbent. Desorption is aided by the application of heat on the sorber/desorber 106 (so as to effect a thermal swing in addition to the pressure swing) . This may be achieved by any suitable source of energy, including electrical energy or the use of waste heat from the refrigerator which the plant 100 is associated with. However, for the plant 100 shown in Figures 1 to 5, the heat is applied to the sorber/desorber 106 by passing steam through the heat transfer tubes of the sorber/desorber 106. These heat transfer tubes may be finned and/or blackened. The steam is generated using the combustion unit 101 to heat the water which was pushed up into the first jacket 102 during the vacuum purge stage (discussed above) . The water is vaporised to steam and flows to the heat transfer tubes of the sorber/desorber 106 through valve 8 before returning to the cool water reservoir 107 via valve 12. The flue gases from the combustion unit 101 are directed to atmosphere during desorption through valve 16. The valve 16 is preferably located above the firebox 118 of the combustion unit 101 so as to facilitate natural draft. The valve 16 may be a pinch valve, in which case it comprises a high temperature resistant flexible elastomer such as silicone. In this embodiment, it is noted that the thermodynamics of the firebox 118 must be designed so that
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the pinch valve 16 is not exposed to an overly high thermal load which may cause it to fail. This silicone tubing may, for example, be connected to ambient heat loss metal tubing, which metal tubing is itself connected at its other end to the hot firebox takeoff via a high temperature insulating material such as PTFE. In another embodiment, the valve 16 may be a poppet valve of any suitable material. In a further embodiment, there is no valve on the flue gas vent from the combustion unit 101. Because of the requirement of a flue gas vent on the combustion unit 101 during desorption, during sorption the volumetric flow rate of combustion gas produced in the combustion unit 101 should exceed the volumetric flow rate into the first liquid ring compressor stage 104 to act against air being drawn in through the flue gas vent and diluting the feed to the first liquid ring compressor stage 104. It is noted that this problem is at least partially mitigated in the embodiments where the valve 16 is present on the flue gas vent. It is also noted that during desorption the heat available for steam generation is not negatively influenced by heat flow to the heat exchange tubing 122. This is achieved by the positive cracking pressure of the check valve 133 together with a portion of the line being of an insulating material such as PTFE.
Continuing the description in relation to the desorption step, the desorbed gases are drawn from the first separator 111 by the second liquid ring compressor 113 into the second top level float separator 112 through valve 14. The second liquid ring compressor 113 also draws in water from the cool water reservoir 107 through valve 5 to the second top level float separator 112 to mix with the carbon dioxide, ie. to carbonate the water. To do so, the second liquid ring compressor 113 is designed to have a suction pressure which is sufficient for this purpose, probably below atmospheric. The second liquid ring compressor stage 105 thus acts as a compressor to compress
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the carbon dioxide, but also as a mixer.
The desorbed gases entering the second liquid ring compressor stage 105 are generally not 100% carbon dioxide, and may still contain some extraneous gases, particularly nitrogen. The bottom level float separator 114 provides a further polishing or scrubbing of the desorbed gases. The float valve 131 of the bottom level float separator 114 closes the flow of liquid to the second separator 115 at a design low level in the bottom level float separator 114. This provides a significant holding time for the liquid in the bottom level float separator 114, during which the extraneous gases, in particular the nitrogen gas, is at least partially separated from the carbon dioxide by virtue of the preferential dissolution of the carbon dioxide in the water over nitrogen. The nitrogen is thus trapped mainly in (and later vented from as described below) the vapour space of the bottom level float separator 114, whilst the carbon dioxide mainly exits the bottom level float separator 114 with the water through the float valve 131 at the bottom of the bottom level float separator 114.
In a variation of the plant described above the circulatory fluid for heating and cooling the sorber/desorber 106 is the condensate in the first liquid ring compressor stage 104 rather than the water from the cool water reservoir 107. In this variation, during the sorption step, the first liquid ring compressor stage 104, either from a take off on the casing of the liquid ring compressor 110 or from the discharge of compressor 110, pumps condensate through heat exchange tubes in a cooling medium within the refrigerator and then through the heat exchange tubes in the sorber/desorber 106 before returning to the liquid ring compressor stage 104 suction. This pumping action or the vacuum purge gases may also be used to push condensate from the heat exchange tubes in the sorber/desorber 106 into the jacket 102 of the combustion unit 101 for steam generation whereafter it is
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predominantly returned by condensing within the heat exchange tubes of the sorber/desorber 106 during desorption.
The above mentioned cooling medium within the refrigerator may be a reservoir of cyclic defrost water from the refrigerator, the contents of which in other embodiments may also be used as a circulatory fluid for heating and cooling the sorber/desorber 106.
The plant 100 also comprises a PDV fill control mechanism 126 for controlling filling of the product drawdown vessel 108. The product drawdown vessel 108 may require gas and/or liquid filling under different conditions, such as at a low liquid level after carbonated water has been dispensed from the product drawdown vessel 108 or at a low pressure level due to some loss of pressure in the vessel 108. The PDV fill control mechanism 126 therefore comprises a low level switch 127 and a low pressure switch 128 on the product drawdown vessel 108. The low level switch 127 activates filling of the product drawdown vessel 108 with carbonated water upon detection of a design low liquid level. The low pressure switch 128 activates input of pressurised carbon dioxide gas to the product drawdown vessel 108 upon detection of a design low pressure level. In activating filling of the product drawdown vessel 108 with either carbonated water or gas, the PDV fill control mechanism thus initiates (and controls) start-up of operation of the plant 100. The low pressure switch 128 is separated from the vapour space in the product drawdown vessel 108 by a membrane 130, so as to act against a low pressure start-up being activated by momentary dispensing of carbonated water from the vessel 108 as opposed to a genuine pressure loss from the vessel 108.
The PDV fill control mechanism also comprises a controllable valve 129 (which is preferably a solenoid valve) on the liquid recycle between the second separator 115 and the second top level float separator 112. On a low
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level start, the controllable valve 129 is closed so that no liquid is recycled from the second separator 115 to the second top level float separator 112. The second separator 115 fills with carbonated water to a designed height until it overflows into the product drawdown vessel 108 through valve 4. This flow of carbonated water into the vapour space of the product drawdown vessel 108 may be over an extended surface or occur as a spray. On a low pressure start, the controllable valve 129 is open allowing recycling of the liquid from the second separator 115 to the second top level float separator 112. The take-off from the separator 115 to the product drawdown vessel 108 is much higher than the recycle outlet, which causes the liquid to preferentially recycle to the second top level float separator 112. Furthermore, the pressure created by the recycle flow on the discharge of check valve 134 restricts flow of water from the cool water reservoir 107 to the second top level float separator 112 in favour of the water recycled from the second separator 115. The carbon dioxide gas at least partially dissociates (by flashing) from the water in the second separator 115, and exits the second separator 115 to flow into the product drawdown vessel 108 through valve 4 to increase the pressure in the product drawdown vessel 108 (and mix with the water therein) . In another embodiment, the controllable valve 129 may be a three way valve thereby eliminating the need for check valve 134.
In a further variation not shown in the Figures the recycle line from the bottom of the second separator 115 to the bottom of the second top level float separator 112 is eliminated with inlet water into the bottom of the second top level float separator 112, for a low pressure start, being via a three way controllable valve from a point below the water level in the product drawdown vessel 108. In this variation, recycling of water occurs through the product drawdown vessel 108 for a low pressure start and the second separator 115 may not be necessary.
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The PDV fill control mechanism also comprises a low level start-up mechanism, which acts against the motor being sent a mixed alternating start-up signal, due to any surface turbulence caused by carbonated water being withdrawn. Preferably, the start-up could be initiated at the first indication of a low level, which latches in the start-up signal for a cycle, for example, by electrical circuitry. A possible electrical circuit which could be used to control operation of the plant 100 is shown in Figure 18. The electrical circuit comprises a latching relay, or a normal relay where a first pole acts as a "hold in" contact. Consequently, the first indication of a low level in the product drawdown vessel will start the cycle. The electrical circuit is also used to control the burner 117, in particular ignition of the burner 117 and the burner's flame safeguard device.
The PDV fill control mechanism may also comprise a processor (in the form of a microchip for example) for monitoring unacceptable gas leakage from the product drawdown vessel 108 by calculating the ratio of low pressure starts to low level starts and comparing it to an acceptable ratio.
At the end of an operation cycle, the plant 100 may undergo a venting step and a drainage step to remove extraneous gases and liquids. This may involve draining the condensate water from the first separator 111 above a designed level through valve 13 to the evaporator tray 125. A similar drain, not shown in Figure 1 may also be performed on the second separator 115. Venting of extraneous gases may also be undertaken to avoid any build up in the plant 100 over repeated cycles due to the fact that the desorption gases are not 100% carbon dioxide. This venting may occur from the bottom level float separator 114 through valves 11 and 12 or through valves 11, 8, 10. It is noted that the main function of the bottom float separator 114 is to trap these gases, which contain mostly nitrogen (which is relatively insoluble in
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water in relation to carbon dioxide) . If desired the venting of extraneous gases from the bottom float separator 114 may occur during the sorption stage (of a subsequent cycle) . The venting of extraneous gases is also performed by a relief valve 132 on the product drawdown vessel 108. This relief valve 132 has a set pressure in the vicinity of 2 bar or above. Venting by this embodiment is mostly during the desorption step. Venting may be carried out exclusively in this way, in which case it is not necessary for the plant 100 to have the bottom level float separator 114. However, this embodiment is likely to incur a higher loss of carbon dioxide than if the venting of extraneous gases is performed using the bottom level float separator 114 in addition to venting from the product drawdown vessel 108. The relief gases from the relief valve 132 may however be bubbled through the cool water reservoir 107 (not shown in Figure 1) so as to increase recovery of carbon dioxide. Once the final venting step has been completed, the plant 100 may initiate another operational cycle if required, or may stay at rest waiting for a signal from the PDV fill control mechanism 126 to start-up operation of the plant 100. Whilst at rest, a first check valve 133 acts to prevent liquid loss from the plant 100, particularly from the first liquid ring compression stage 104. λlthough, if any liquid is lost, this could be made up with process condensate or cyclic defrost from the refrigerator with which the plant 100 is associated. It may also be desirable to fill the sorbent bed of the sorber/desorber 106 with combustion gases so as to minimise oxidative degradation of the sorbent whilst the plant 100 is at rest.
It should be noted also that if valves 1 and 2 are pinch valves, that it is preferable that they should remain open in the rest position, especially valve 2. This is to avoid any compression set in the flexible tube which
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may occur over an extended period of time in the closed position being compounded by a vacuum application. Under such conditions the flexible tube may not open in the desired fashion. This is less of a problem for tubes under pressure. Consequently, in an embodiment using pinch valves, valves 1, 2 and 3 are open in the rest position with valve 2 closing on start up.
Referring more specifically to Figure 1, the plant 100 also comprises a back flow mitigation system 140 for mitigating any backflow of mains water into the sorber/desorber 106. The backflow mitigation system 140 is designed to mitigate backflow even when there is no power supplied to the plant 100. This is particularly important in the event of a power cut to the plant 100 during some part of the operational cycle described above when valves are opened. With no power supply, the compressors 110,113 will cease to operate and the plant 100 is therefore susceptible to mains water undesirably flowing into the sorber/desorber 106. Mitigation of the backflow of mains water into the sorber/desorber 106 is required to protect the sorbent bed from being inactivated, or otherwise damaged, by contact with a significant amount of mains water. The backflow mitigation system 140 firstly comprises the use of process condensate derived from the combustion reaction as the liquid in the first liquid ring compressor stage 104.
The backflow mitigation system 140 also comprises a second check valve 141 located between the sorber/desorber 106 and the cool water reservoir 107. The second check valve 141 at all times only allows fluid flow in one direction, specifically fluid flow away from the sorber/desorber 106. The second check valve 141 is preferably located between the second liquid ring compression stage 105, which uses mains water, and the first liquid ring compression stage 104, which does not.
The backflow mitigation system 140 also comprises demisters 142 in the first and second top level float
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separators 109, 112 for extracting excess moisture from the gas in the gas space in the top level float separators. The float valve 143 in the second top level float separator 112 also forms part of the backflow mitigation system 140 by acting against the second top level float separator 112 from overfilling with water and backflowing.
The plant 100 also comprises a water balance system for balancing the water produced in the combustion reaction by disposing water from the plant. Water from the combustion reaction is condensed in the first liquid compressor stage 104 and also in the sorber/desorber 106 and requires balancing to prevent overflow and/or excessive water accumulation in these units. The water balance system comprises an evaporator tray 125 on which the disposed water may be evaporated.
Evaporation on the evaporator tray 125 may occur using the waste heat of the refrigerator in relation to which the plant 100 is associated. Evaporation may also occur using other process heat such as from the jackets 102, 103 of the combustion unit 101 or ambient thermal energy.
The disposed water includes accumulated water within the first liquid ring compressor stage 104 which is directed to the evaporator tray 125 at a suitable time in the operation of the plant 100, most preferably at the end of a cycle, by opening valve 13 on the first separator 111. The disposed water also includes accumulated water within the sorber/desorber 106 which is directed, during the pressure release step to the second jacket 103 of the combustion unit 101, and any remaining water after evaporation in the second jacket 103 is directed to the evaporator tray 125.
In other variations, the disposed water is collected rather than sent to an evaporator tray, either for physical disposal or incorporation into the carbonated water product.
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In a variation of the plant described above, instead of the liquid ring compressor stages 104, 105, the plant could comprise a compressor for compressing gases and at least one pump for pumping and pressurising of liquids. If the plant only comprised one pump, then it may be required to provide the high pressure function of pressurising mains water for mixing with the carbon dioxide as well as the low pressure function of circulating the cooling water through the sorber/desorber 106 during desorption. In another embodiment, the plant may comprise two pumps, one for carrying out each of these functions . The advantage of separate flow streams for water and gases is that there would be less potential for mains water contamination of the sorbent bed in the sorber/desorber.
In a further variation, the plant may comprise only one pump, which is a low pressure pump for circulating the cooling and heating water, with the compressor instead of a mechanical pump providing the high pressure function of pressurising the mains water into the plant by using compressed gas from the compressor to act as a fluid displacement pump. A plant 200 for producing carbonated water according to another embodiment of the present invention, and having this particular variation is shown in Figures 6 to 12. Although this plant 200 would be more bulky than the plant 100 outlined in Figures 1 to 5, it would advantageously be of low cost and maintenance.
The plant 200 is also particularly suitable for use in relation to a refrigerator. Similar features of the plant 200 to the plant 100 shown in Figures 1 to 5 have been designated with the same reference number, but have been prefixed with the numeral 2 instead of 1.
The plant 200 comprises a combustion unit 201, a sorber/desorber 206, a cool water reservoir 207 and a product drawdown vessel 208. The plant 200 also comprises a compressor 250, a pump 251, a fluid displacement or acid egg vessel 252, and a venting or carbonator vessel 253.
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The compressor 250 may comprise a two or more stage compressor or may comprise a single stage compressor. The compressor 250 is also preferably of a type which draws in minimal air from atmosphere when used as a vacuum pump.
In one embodiment, the compressor 250 may be a double-acting two stage articulating piston compressor with a dedicated piston shape as shown in Figure 13. This type of compressor offers a high compression ratio in a compact single unit. Air ingress is minimal, as the piston seals are not exposed to atmosphere. Furthermore, the second stage of the compressor, where the shaft enters is a more highly pressurised stage, ensuring any leakage will be to atmosphere rather than drawing in air. Figure 14 shows a variation of the piston compressor in which it also acts to drive the pump 251 in the form of a positive displacement water pump. It is noted such a pumping configuration could also be incorporated into the plant 100 of Figure 1 as a substitute for the liquid ring compressor (s) . A diaphragm compressor and a peristaltic compressor are other types of compressors which draw in minimal air when used as a vacuum pump.
Where the compressor is a peristaltic compressor it may comprise a multi channel compressor with different diameter tubing. So as to extend tubing life and selection there may be cooling between successive compressors in series, thereby dissipating heat and inducing condensation which acts as a buffer against temperature increase. In addition to compression functions during sorption and desorption over the sorber/desorber 206, the compressor 250 is for acting as a fluid displacement pump to introduce mains water into the plant 200. This is done by compressing gas into the fluid displacement vessel 252 so as to pressurise the mains water therein. In doing so, the water is pushed into the otherwise isolated venting vessel 253. The venting vessel 253 has been in fluid communication with the product drawdown vessel 208 and is
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thus filled mainly with carbon dioxide gas. Therefore some recovery of the carbon dioxide with water to produce carbonated water occurs in the venting vessel 253. Enrichment of extraneous gases (largely nitrogen) in the vapour space is allowed to occur in the venting vessel 253 due to the preferential dissolution of the carbon dioxide in the water, which is followed by subsequent venting of these extraneous gases. A liquid seal is maintained between the two vessels 252, 253, by virtue of the greater volume of water in the fluid displacement vessel 252 relative to the volume of the venting vessel 253.
The fluid displacement vessel 252 is gravity filled (and re- filled) from the cool water reservoir 207, by locating the fluid displacement vessel 252 at an appropriate height with respect to the cool water reservoir 207.
In another embodiment, not shown in the figures, the compressor 250 acts as a vacuum pump to introduce mains water into the plant. Therein one vacuum fill vessel replaces the two vessels 252,253. This vacuum fill vessel has characteristics of both vessels 252,253. The vacuum fill vessel is connected to the cool water reservoir 207 in the same manner as the fluid displacement vessel 252 and is in fluid communication with the product drawdown vessel 208 in the same manner as the venting vessel 253. It is also placed above the product drawdown vessel 208.
Consequently, at an appropriate time in the cycle, the compressor takes suction from the vacuum fill vessel and evacuates the mainly carbon dioxide gaseous contents to the vapour space of the product drawdown vessel 208. The vacuum fill vessel may then be filled by the vacuum drawing in water from the cool water reservoir 207 or possibly even by gravity fill. Thereafter, the vacuum fill vessel is isolated from the cool water reservoir 208 and comes into fluid communication with the product drawdown vessel 208 during the desorption step.
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In this embodiment, venting of extraneous gases is from a relief valve on the vacuum fill vessel or the product drawdown vessel 208. However, in venting in this manner more carbon dioxide is likely to be lost as opposed to carrying this step out in the venting vessel 253 of the previous embodiment .
In an embodiment, more than one vacuum fill cycle may be performed for a full operational cycle of the plant 200, thereby minimizing the size of the vacuum fill vessel for the addition of a fixed amount of mains water to the plant 200.
Also the water may be transferred from the vacuum fill vessel to the product drawdown vessel 208 by means other than gravity by using the desorption gases to pressurise the water in the vacuum fill vessel into the product drawdown vessel 208.
Continuing the description in relation to the plant 200:
The plant 200 also comprises a valve system 220 for directing the fluid flow during the operation of the plant 200 at the different operation steps. The valve system 220 comprises a plurality of valves (marked 20-36) .
The plant 200 also comprises a pre-cooler 254 for cooling as well as scrubbing and dehumidifying the combustion gases from the combustion unit 201 . The pre- cooler 254 comprises a vessel containing water, through which the combustion gases are bubbled. The heat lost to the water in the pre-cooler 254 from the combustion gases is used as a heat source for heating the sorber/desorber 206 during desorption. This occurs by flowing water through heat exchange tubes in the pre-cooler 254 and then through heat exchange tubes in the sorber/desorber 206.
The pre-cooler 254 has an inlet for mitigating noise created by the downward flow of condensation against the upward flow of combustion gases entering the pre- cooler 254 from the combustion unit 201 . The inlet is shown comprising two tubes; an inner tube 255 and an outer
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tube 256, the inner tube 255 being located inside the outer tube 256. The inner tube 255 receives the combustion gases from the combustion unit 201 at its lower end, the gases escaping from the inner tube 255 at its upper end, into the outer tube 256. The outer tube 256 is sealed at its upper end, to prevent gases from leaving the outer tube 256 at its upper end. Spaces 257 are provided at the lower end of the outer tube 256 for the gases to pass out of the outer tube 256 and into the pre-cooler space. The outer tube 256 acts as insulation for the inner tube 256, thus acting against the condensation of the water formed in the combustion reaction in the inner tube 256. Any condensation formed in the inner tube 255 would tend to flow downwardly under gravity against the upward flow of the combustion gases, thus creating noise. Instead condensation is primarily formed in the outer tube 256, where it flows downwardly under gravity in the same direction as the flow of the combustion gases, which does not create much noise. In other embodiments, the inlet of the pre- cooler could be an inlet tube surrounded by insulation material or a venturi nozzle, which would also mitigate noise.
Notably, the tubes 255, 256 are designed whereby the top of the inner tube 255 is above the water level in the pre-cooler 254 when no combustion gases are passing through the pre-cooler 254 and the gas head space in the pre-cooler 254 is at atmospheric pressure. This means that when at these conditions, water does not flow down the inner tube 255 and possibly into the combustion unit 201 . In addition, the outer tube 256 is designed whereby its top is just submerged in the water in the pre-cooler 254 during sorption to avoid heating of the gas space in the pre-cooler 254. The pre-cooler 254 also has a water volume control mechanism in the form of a gravity drainage leg 258. The drainage leg 258 controls the water volume in the
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pre-cooler 254 by allowing excess water above a design water level to exit the pre-cooler 254 through the drainage leg 258 under gravity, at an appropriate time in the operation of the plant 200. Generally this is when the pre-cooler 254 has been allowed to return to atmospheric pressure, and no combustion gases are being bubbled through. This drainage is required because the volume of water in the pre-cooler 254 increases as combustion gases are bubbled therethrough and the water produced in the combustion reaction is condensed out into the pre-cooler water. The drained water from the pre-cooler 254 is sent by gravity drainage leg 258 to the evaporator 225. The drainage of the excess water from the pre-cooler 254 also provides the function of purging impurities that may build up in the pre-cooler water, having been scrubbed from the combustion gases. It is noted that valve 29 on the drainage leg 258 is opened and closed appropriately to act against air ingress to the pre-cooler 254 through the drainage leg 258. It is also possible that the volume of water in the pre-cooler 254 may decrease, due potentially to evaporation to atmosphere through valve 33 (which is open when the plant 200 is at rest to allow the pre-cooler 254 to be at atmospheric pressure) or through valve 29 or even through the inner tube 255 and the combustion unit 201. In this case defrost water from the refrigerator may be inputted to the pre-cooler 254 through the water volume control mechanism in the form of the gravity drainage leg 258 to make up this lost volume of water in the pre-cooler 254.
It is noted that the pre-cooler 254 described above, could be incorporated within the plant 100 described above in relation to Figures 1 to 5.
The plant 200 also operates according to a batch process involving the four general steps of sorption, pressure release, vacuum purge and desorption. The plant 200 also involves the steps of water pressurisation, fluid
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displacement vessel filling and venting which occur concurrently with sorption.
Referring now to Figures 7, 8 and 9, in conjunction with Figure 6, the significant components of the plant 200 involved in the sorption step of the operation of the plant 200 are shown. The components of the plant 200 involved in the steps of water pressurisation (Figure 7) , fluid displacement vessel filling (Figure 8) and venting (Figure 9) which occur in that order and concurrently with sorption, are also shown.
Natural gas is combusted in the combustion unit 201 according to the aforementioned reaction and the combustion product gases are bubbled through the pre- cooler 254 to cool, scrub and de-humidify them. The compressor 250, draws the gas through pre-cooler 254 and valve 20, compressing at least a substantial component of the gas into the sorber/desorber 206 through valve 23, where the carbon dioxide is preferentially sorbed onto the sorbent bed. It is noted that the volumetric flow rate into the compressor 250 from the pre-cooler 254, together with the positioning of the spaces 257 in the outer tube 257 of the pre-cooler inlet should be designed so as to avoid drawing air into the pre-cooler through the gravity drainage leg 258. The same effect could be achieved through closure of valve 29.
Sorption is aided by the flow of cooling water though heat exchanger tubes in the sorber/desorber 206. This is driven by the pump 251, which draws mains water from the cool water reservoir 207 through valve 24 and pumps it through the heat exchanger tubes of the sorber/desorber 206. The cooling water returns to the cool water reservoir 207 via valve 26.
In a particular embodiment, the pump 251 during the sorption step is an air lift pump using relief gases from the sorber/desorber 106.
As discussed, during the sorption step, the steps of water pressurisation (Figure 7) , fluid displacement
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vessel filling (Figure 8) and venting (Figure 9) also occur. Firstly, water pressurisation, in which the compressor 250 is used to act as a fluid displacement pump, by taking some of the compressed gases outputted by the compressor 250 through valve 34, and using it to pressurise the water which is in the fluid displacement vessel 252. This also causes the water in the fluid displacement vessel 252 to be "pumped" into the otherwise isolated venting vessel 253 through valve 35. The water rises in the venting vessel 253 so as to reach an equilibrium fill level where the gases in the vapour space of the venting vessel 253 are sufficiently pressurised so as to resist any further rise in the water level in the venting vessel 253. The venting vessel 253 has been previously in fluid communication with the product drawdown vessel 208 and is thus filled with mainly carbon dioxide. Thus, as the water is pressurised into the venting vessel 253 from the fluid displacement vessel 252, some mixing of the water with carbon dioxide to produce carbonated water occurs.
Once this is finished, valves 34 and 35 are closed (which isolates the venting vessel 253) and valve 31 first and then valve 32 are opened to start the step of fluid displacement vessel filling (Figure 8) . This also means that all of the compressed gas from the compressor 250 is now being sent to the sorber/desorber 206. The fluid displacement vessel 252 is filled under gravity through valve 32 from the cool water reservoir 207. As this occurs, gas left in the fluid displacement vessel 252 from the prior step of water pressurisation is displaced through the top of the vessel through valve 31 and sent to the evaporator tray 225 (and therefore to atmosphere) .
Once this is finished, valve 32 is closed (but valve 31 is left open) and valve 35 is opened to allow for venting of extraneous gases which are mainly nitrogen, from the venting vessel 253 (Figure 9) . The desorbed gases which were in the venting vessel 253 were not 100%
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carbon dioxide. However, by holding the carbonated water in the venting vessel 253 for a sufficient holding time, the extraneous gases , in particular the nitrogen gas, have become enriched in the vapour space by virtue of the preferential dissolution of the carbon dioxide in the water over nitrogen.
The vented gas, is vented from the top of the venting vessel 253 through valve 35 to the bottom of the fluid displacement vessel 252. This provides for some recovery of any carbon dioxide in the venting gases (and which would otherwise be lost) by dissolution of the carbon dioxide in the water in the fluid displacement vessel 252. The vented gas, bubbles through the fluid displacement vessel 252 and escapes at its top to flow to the evaporator 225 (and hence to atmosphere) through valve 31.
Referring now to Figure 10 (in conjunction with Figure 6) , the next step in the operation of the plant 200 is pressure release . The sorber/desorber 206 is isolated from gaseous feed by the closure of valve 20 . The sorber/desorber 206 is subsequently let down to atmospheric pressure by opening valve 28, which directs gas to the evaporator tray 225 for evaporation of any condensation in the let down gas . Referring now to Figure 11 (in conjunction with
Figure 6) , the next step in the operation of the plant 200 is vacuum purge. The vacuum purge step occurs by opening valve 21 and vacuuming a substantial amount of the extraneous gas out of the sorber/desorber 206 through the compressor 250.
An optional recycle of the gas across the compressor 250 (ie. from its outlet to its inlet) may be provided through valve 23. The previously mentioned vacuum valve may also be incorporated. The vacuum purged gases may be subsequently vented to atmosphere from the compressor outlet. However, preferably, the gas flows from the outlet of the
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compressor 250 through valve 34 into the fluid displacement vessel 252. This is to recover at least some of the carbon dioxide in the vacuum purged gases by dissolution of the carbon dioxide in the water in the fluid displacement vessel 252. The vacuum purged gases are eventually vented to atmosphere from the fluid displacement vessel 252 through valve 31.
Referring now to Figure 12, in conjunction with Figure 6, the next process in the operation of the plant 200 is desorption of the carbon dioxide from the sorber/desorber 206 which includes compression of the carbon dioxide and further carbonation (mixing with water) .
Desorption occurs with the compressor 250 continuing to apply vacuum on the sorber/desorber 206 through valve 21. The compressor 250 compresses this mainly carbon dioxide gas into the venting vessel 253 through valve 22 . The venting vessel 253 is now in gas and liquid communication with the product drawdown vessel 208 through valves 30 and 36. Notably, the venting vessel 253 is positioned above the product drawdown vessel 208, so that the liquid flows to the product drawdown vessel 208 through valve 30 under gravity. Because valves 30 and 36 are open, the venting vessel 253 and product drawdown vessel 208 act as a single volume during desorption.
Furthermore, these valves remain open once operation of a single cycle of the plant 200 is complete, and stay open during any periodic dispensing from the product drawdown vessel 208. The valves 30 and 36 are closed upon start-up of operation of the plant, which begins with the sorption step.
It is desirable to ensure that the venting vessel 253 is emptied of liquid by the end of the desorption step to act against a low level signal being recognised in the product drawdown vessel 208 and operation of the plant 200 commenced with carbonated water in the venting vessel 253. Desorption is aided by the application of heat on
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the sorber/desorber 206 (so as to effect a thermal swing in addition to the pressure swing) . This may be achieved by any suitable source of energy, including the use of waste heat from the refrigerator which the plant 200 is associated with. However, for the plant 200 shown in Figures 6 to 12, the heat is applied to the sorber/desorber 206 by pumping water from the discharge of pump 251 through heat exchanger tubes in the sorber/desorber 206 and then via valve 27 through heat exchange tubes in the pre-cooler 254 where it is heated by hot water in the pre-cooler 254. Thereafter, the water recirculates to the suction of pump 251 via valve 25. The water in the pre-cooler 254 has been heated by the combustion gases during sorption. However, it may be necessary during desorption to continue heating the pre- cooler water by combusting natural gas in the combustion unit 201. During this step, the pump 251 does not need to draw on any water from the cool water reservoir 207, but instead re-circulates the water which was left in the tubing after the sorption step.
In a variation not shown in the figures, heat is applied to sorber/desorber 206 during desorption by recirculating (using pump 251) the heated pre-cooler water directly into the heat exchanger tubes of the sorber/desorber 206 and then back to the pre-cooler 254 without the need for heat exchange tubes in the pre-cooler 254. This configuration should deliver superior heat transfer.
However, on the next cycle, during sorption the volume of water in the sorber/desorber heat exchange tubes between the changeover valves, which had been derived from direct contact with combustion gases, is transferred to the cool water reservoir 207. Though small in volume its potability, given its direct contact with combustion gases and its impurities is uncertain. The cool water reservoir 207 is the source of water feed to the plant 200 and therefore the carbonated water produced by the plant 200
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may become contaminated by this variation.
In another embodiment not shown on the figures, it may also be possible to use an automatic drain on the discharge of the positive displacement compressor 250, especially during desorption. Thereby condensation caused in the compressor 250 may be used to scrub desorption gases of impurities with the condensate directed to the evaporator 225 rather than the carbonated water product. The plant 200 also comprises a backflow mitigation system 240 for mitigating any backflow of mains water into the sorber/desorber 206, in particular when there is a power cut to the plant 200. The backflow mitigation system 240 comprises firstly desorbing into the vapour space of the venting vessel 253 rather than the normal procedure of introducing carbonating gases below the water level and secondly comprises a first check valve 260, located between the venting vessel 253 and the sorber/desorber 206, more specifically between the venting vessel 253 and the outlet of the compressor 250. The first check valve 260 prevents backflow of water from the venting vessel 253 to the sorber/desorber 206. The plant also comprises a second backflow mitigation system 241. The second backflow mitigation system 241 comprises a second check valve 235 between the suction of compressor 250 and gaseous space of the pre-cooler 254. This check valve 235 acts to prevent pressurised gases feeding back into the pre-cooler 254 during a power cut. Such pressurisation could push water from the pre-cooler 254 via the inner tube 255 and the firebox 201. Not only would this extinguish the flame but there would be no cooling of combustion gases on further cycles, thereby damaging the compressor. The second backflow mitigation system 241 may also comprise a thermostat switch on the compressor 250 or a level switch on the pre-cooler 254 to provide an added precaution against this eventuality.
Referring now to Figure 15, a plant 300 for producing carbonated water according to a further
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embodiment of the present invention is shown. The plant 300 is also particularly suitable for use in relation to a refrigerator. Similar features of the plant 300 to the plant 100 shown in Figures 1 to 5 have been designated with the same reference number, but have been prefixed with the numeral 3 instead of 1.
The plant 300 purifies the carbon dioxide by filtration and therefore can operate on a continuous basis for the duration of a cycle. The plant 300 comprises a combustion unit 301, a cool water reservoir 307 and a product drawdown vessel 308. The plant 300 also comprises at least one, preferably two membranes 370, 371. The membranes 370, 371 may be any suitable membranes, such as anion exchange membranes for example. The plant 300 also comprises a compressor for each of the membranes. The two membrane compressors 372, 373 are each for forcing the combustion gases through its respective membrane 370, 371 to form a filtrate on one side containing mostly carbon dioxide and a rentate on the other side containing mostly impurities. In Figure 15 , the membrane compressors 372, 373 are liquid ring compressors. The liquid used in the liquid ring membrane compressors 372, 373 is condensate from the combustion reaction. The membrane compressors 372, 373 could, of course, be any other suitable type of compressor.
The plant 300 also comprises at least one further compressor, preferably two further compressors 374, 375 for pressurisation and mixing of the filtered gases from the membranes 370, 371 and the mains water, drawn from the cool water reservoir 307. As shown in Figure 15 the two further compressors 374, 375 are two individual liquid ring compressors contained within a single stage. However, each individual compressor may be contained within its own stage. The compressors 372, 373, 374, 375 of the plant 300 may be a single unit driven by the same motor or be separate units driven by separate motors. In a variation, one of the further compressors could be a compressor for
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compressing the carbon dioxide gas, and the other further compressor could be a pump for pressurising the water. In this variation, the pressurised gas and the pressurised water could be mixed to produce carbonated water either in the product drawdown vessel 308 or in another vessel.
In a further embodiment of the invention not shown in the figures, the sorber/desorber may be replaced with a membrane-contactor (such as the membrane-contactor described in Society Automotive Engineers (US) Technical Paper 901295) . The circulating liquid sorbent sorbs carbon dioxide through one membrane and desorbs through another membrane .
Referring now to Figure 16, a plant 400 for producing carbonated water according a further embodiment of the present invention is shown. The plant 400 is also particularly suitable for use in relation to a refrigerator. Similar features of the plant 400 to the plant 100 shown in Figures 1 to 5 have been designated with the same reference number, but have been prefixed with the numeral 4 instead of 1.
The plant 400 provides an illustration of how carbon dioxide, purified by processes other than membrane filtration or swing sorption or available as a by-product in a substantially purified form could be pressurised and mixed with water to produce carbonated water. The plant
400 is essentially the end section of the plants 100, 200, 300, comprising a liquid ring compressor 480 to compress and mix the substantially purified carbon dioxide gas and mains water from the cool water reservoir 407, to produce carbonated water. The carbonated water being sent to the product drawdown vessel 408 for storage and dispensing.
The processing units of plants 100,200,300,400 may be positioned in a number of locations in relation to a refrigerator. A particular configuration may be dependent on other design aspects of the refrigerator.
Processing units which are not for refrigerated water storage may, for example, be located in the ambient
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space under the refrigerator. This includes the sorber/desorber 106. This may be advantageously achieved by placing the processing units on a slidable tray which fits behind the air grille at the bottom front of the refrigerator (not shown) . The tray and grille may even be one piece. The tray may slide out for inspection and maintenance of the processing units. In this embodiment the product drawdown vessel 108, 208, 308, 408 may be advantageously located in the door of the fresh food section of the refrigerator as shown elsewhere herein.
In another embodiment, for a side-by- side refrigerator a dispensing conduit (not shown) may extend from the product drawdown vessel 108, 208, 308, 408 from a location in the above freezing fresh food section of a refrigerator to the ambient space under the refrigerator, and then to a dispenser in the door of the freezer section of the refrigerator (not shown) . This is a pathway commonly used by still water dispensers in side-by- side refrigerators . The heat gain to the carbonated water product through this ambient exposure may be counteracted by similar means used to counteract the ambient exposure for still water dispensing such as recycling the carbonated water via the dispenser inlet side through the product drawdown vessel 108 208 308 408 using a pump (not shown) . Other means may include the provision of an insulated jacket (not shown) . This cooling means for the carbonated water dispenser may be separate from or in common with the still water dispenser's cooling means. For example the jacket may surround both the still water and the carbonated water dispensing conduits. Refrigerated air or cooling water is circulated through the insulated jacket, such as from the cool water reservoir 107, 207, 307, 407 by a pump (not shown) . In another arrangement the dispensing conduit which extends through the cool water reservoir 107 207 307 407 to the dispenser may be formed (at least in part) from
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insulated heat conducting metal tubing. In this arrangement heat is conducted along the metal tubing to make up for ambient exposure heat gain. In a further variation a flexible piece of metal wire may be positioned in a plastic dispensing conduit so as to have one end in the product drawdown vessel 108,208,308,408 and one end near the dispenser (not shown) .The wire may or may not be fixed at either end and may have an extended surface area associated with the product drawdown vessel 107, 207, 307, 407. As the heat travels more quickly along the metal than the water this will act against the ambient section warming .
In a further variation, a separate above freezing compartment (not shown) may be located in the freezer door (not shown) to house the product drawdown vessel 108,
208,308, 408 and possibly also at least a portion of the still water inventory. This smaller above freezing compartment in the freezer door may be appropriately cooled by directing refrigerated air through the compartment in a similar way used to cool the above freezing fresh food section of the refrigerator.
Indeed refrigerated air may be recirculated so as to flow through the fresh food section via the above mentioned insulated jacket then via the abovementioned compartment in the freezer door and finally via the freezer section of the side-by-side refrigerator.
Although the plants 100, 200, 300, 400 are of particular application in the incorporation in relation to a refrigerator or other refrigerated device such as a water cooler they may be adapted for use in other applications. For example, a plant according to embodiments of the present invention may be used in respect of a fermentation plant (such as in the brewing of beer) where the fermentation gases (comprising mostly carbon dioxide) can be captured and sent to the plant for the production of carbonated water.
Referring now to Figure 17, the plants 100, 200,
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300, 400 may be integrated with a soft drink plant 500 for the production and dispensing of soft drinks. This may be done by mixing carbonated water from the product drawdown vessel 108, 208, 308, 408 with syrup from any one of one or more syrup packages 501 in a post-mix manner. It is noted that the vapour space of the product drawdown vessel 108, 208, 308, 408 is in fluid communication with the syrup packages 501 so as to carbonate and act as a propellent of the syrup from the syrup packages 501 in the post-mix production of the soft drinks. The soft drink plant 500 may also be able to fill a removable container with a post-mix soft drink by separate or combined dispensing of the soda water and carbonated syrup from the dispense tap shown in Figure 17, whereafter the removable container may be manually sealed.
Alternatively, the soft drink plant 500 could be used in a pre-mix manner to carbonate the contents of the removable container 502 which has been previously filled with uncarbonated water and uncarbonated syrup. This may be done by exposing the vapour space in the removable container to the vapour space of the product drawdown vessel 108, 208, 308, 408 possibly via a check valve. The soft drink plant 500 may comprise a manual three port, two position valve 503 to achieve this. The valve 503 may also act as a snift valve to purge any air originally in the vapour space of the removable container 502 to atmosphere by at least one set of successive pressurising and venting steps . Once the air has been purged from the vapour space of the removable container 502 it may be allowed to reach equilibrium with the vapour space of the product drawdown vessel 108, 208, 308, 408. In another embodiment, if it is desired to achieve a faster carbonation, a sparger line may be utilised to carbonate below the surface of liquid in the removable container 502, rather than into the vapour space. In this instance, while retaining the snift valve function, the manual valve may be a three position multi port valve. It may also be advantageous in this
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embodiment to have a check valve in the line acting against backflow through the sparger line into the product drawdown vessel 108, 208, 308, 408, should the pressure decrease in the product drawdown vessel 108, 208, 308, 408, as from a drawdown of product. The removable container 502 is subsequently detached from the soft drink plant 500 and sealed.
Carbonated water is produced by providing a gas containing carbon dioxide and mixing the gas containing carbon dioxide with water in a vessel. The gas may be provided for example by burning natural gas on site and mixing the purified combustion products with the water in the plants and processes as described above.
In a variation, the step of providing the carbon dioxide involves providing a pressurized carbon dioxide cylinder.
However the gas is provided and mixed with the water, subsequent to the mixing, further embodiments of the present invention also comprise allowing gas from the water-gas mixture in the vessel to accumulate in a chamber. This accumulated gas or at least a portion of the accumulated gas is vented from the chamber when dispensing carbonated water from the vessel or during filling of the vessel. In carbonating the water, the solubility of the carbon dioxide in the water is dependent on the temperature and pressure of the water and the presence of any other gases in the system. Although the carbon dioxide may be fed to the vessel as an essentially pure source, extraneous gases are dissolved in the water (from outside the plant 600) and also enter the vessel. These gases are mainly, nitrogen (given that it is the main constituent of air) and oxygen. Some of the extraneous gases will be displaced from the water by the carbon dioxide occupying any gas space in fluid communication with the vessel, including any space created by the dispensing of carbonated water from the vessel. If no
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action is taken to remove the extraneous gases (and any other undesired extraneous gases) , over time with continued dispensing , the gas pressure of the extraneous gases and other extraneous gases in the vessel increases, making it difficult to feed carbon dioxide in the vessel. Further, the concentration of these extraneous gases in the vessel increases, which will then be preferentially- dissolved in the water over the carbon dioxide based on their partial pressures. As a result, the carbonated water may go "flat" because not enough carbon dioxide is being dissolved into the water.
Gases may be vented to alleviate this problem, however, care must be taken in venting gases from the vessel as carbon dioxide will be vented at the same time as any extraneous gases. Therefore, excessive venting will be wasteful of carbon dioxide feed, as well as reducing the pressure in the vessel and hence the amount of carbonation of the water.
Further embodiments of the present invention are concerned with an improved plant and method for producing carbonated water especially in relation to a refrigerator and further where the carbonated water is dispensed in conjunction with still water from a refrigerator.
The embodiments may however be adapted to other water dispensing devices such as a water cooler.
Carbonation systems using an installed pressurized cylinder of carbon dioxide may be of various types, including systems which use a source of pressurized water either from a mains water supply or a pump and other systems which rely on the user delivering an essentially manual burst of carbon dioxide gas in a batch manner to a fixed amount of still water in a container but without an essential inventory of already produced carbonated water to drawn on. The plants of these embodiments of the present invention rely on an essential on demand inventory of carbonated water for the consumer to draw on and a
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pressurized source of water either from a mains water supply or a pump
Referring now to Figure 19, a plant 600 for producing and dispensing carbonated water according to an embodiment of the present invention is shown. The plant 600 is particularly useful for incorporation into a refrigerator with a mains water feed. The carbonated water may be dispensed in conjunction with cold still water . The plant 600 comprises a suitably pressurized water feed 601, a still water holding tank 602, a pressurized carbon dioxide feed 603, a vessel 604, an external chamber 605, a venting system comprising a three way dispensing valve 606 and a dispenser for dispending carbonated water 607. The water from the water feed 601 may flow through a check valve 615 of a type required by regulatory authorities and/or a treatment device (not shown) such as a carbon filter before entering the holding tank 602. The pressurized carbon dioxide feed 603 is preferably provided from a cylinder of a gas containing carbon dioxide.
The vessel 604 comprises inner and outer passages 608 and 609 respectively which are in fluid communication and provide opposing flow paths. That is, the inlet of the inner passage 608 is located at the same end of the vessel 604 as the outlet of the outer passage 609. Similarly, the outlet of inner passage 608 is in fluid communication with and located at the same end of the vessel 604 as the inlet of the outer passage 609. The passages 608 and 609 are separated by a tube 610 provided inside the vessel 604. The passages 608, 609 may be aligned substantially horizontally or vertically. However, for the plant 600 the flow passages 608 and 609 are substantially vertical. In another embodiment to that shown in Figure 19, the passages (which provide opposing flow paths) may comprise carbonated water product off take tubing entering the top and extending to near the bottom of a larger diameter feed
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tube .
In another variation, the vessel may comprise a plurality of passages. For example, this may involve more than one concentric passages. In another variation, the plurality of passages of the vessel may comprise a hose tank. A hose tank is characterized by a small diameter and long length. The long length may be effectively "compressed" so as to allow the hose tank to fit in a particular dimensional space. This may be achieved by coiling a particular length of hose into a substantially spiral shape or by forming successive opposed U tubes. In either case the hose tank may be considered to have a plurality of passages which provide opposing flow paths to each adjacent passage. Referring again to Figure 19, pressurized cold water, from the still water holding tank 602, such as a hose tank in the back of a refrigerator, flows into the top of the inner passage 608 of the vessel 604 (although in another arrangement it could be the top of the outer passage 609) , via a pressure differential valve 611, check valve 612, and a controller in the form of a throttling valve 613.
The pressure differential valve 611 is for acting to maintain the pressure of the carbon dioxide below the pressure of the water between the vessel 604 and the holding tank 602 so as to mitigate backflow of carbon dioxide. This pressure differential could, however, be achieved in any other suitable way. The check valve 612 is for maintaining the integrity of the water in the holding tank 602 and the vessel 604 (ie. to prevent backflow of the carbonated water) . The controller in the form of the throttling valve 613 is for controlling water flow into the vessel 604 so as to adjust the relative amount of carbon dioxide to water flowing into the vessel 604.
The gas containing carbon dioxide also flows into the top of the inner passage 608 (although in another
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arrangement it could be the top of the outer passage 609) via the pressure differential valve 611 and the check valve 616. The check valve 616 is for ensuring the integrity of carbon dioxide gas upstream of it. Although the gas containing carbon dioxide has a lower pressure than the water at the pressure differential valve 611, due to the water pressure drop across the check valve 612 and the throttling valve 613, the gas containing carbon dioxide is at sufficient pressure to enter the inner passage 608 together with the water.
The vessel 604 is for carbonating and mixing but it is also for storage of the product carbonated water. Most of the mixing is done in the inner passage 608. The tube 610 separates the inner passage 608 and outer passage 609 and helps to ensure incoming water and incoming gas containing carbon dioxide are not mixed with the product off take from the dispensing valve 606. For most demand scenarios the tube 610 should be sized appropriately so that the inner passage 608 is not filled with the gas containing carbon dioxide on dispensing of product.
However, extra valving such as an automatic drain float valve (not shown) at the bottom of the inner flow passage 608 separating the two passages 608 and 609 could be provided so that should this occur, carbon dioxide gas does not "blast" through to the dispenser 607. An automatic drain float valve is a float valve that closes when a design low liquid level is reached.
While it is preferable that both the gas containing carbon dioxide and water enter at the top of the vessel 604 they could enter in the mixing tank 604 in any possible arrangement. The gas containing carbon dioxide for example may enter as bubbles below the water surface in the vessel 604 but preferably this should not be so low as to generate mixing between the passages 608, 609.
Where the water enters at the top of the vessel 604, it may enter as a spray or droplets or may be
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directed to flow over an extended surface area which may include the walls of the inner passage 608.
The dispensing valve 606 is a three way valve which when at rest and no carbonated product is being dispensed, is aligned so that the top of the inner passage 608 and the top of the outer passage 609 are in fluid communication through the external chamber 605 which is above the top of the inner passage 608.
The vessel 604 is essentially full of liquid when at rest and at equilibrium. That is, it does not have a designed for fixed gaseous head space as may be achieved by incorporation of a float valve system for example. It will still experience a gaseous space build up in a designed for manner but this will be transient and not fixed at any particular location.
Any gases that do build up at the top of the inner passage 608 will, by proper sizing of the external chamber 605 and the inlet line 614 connecting the inner passage 608 to the external chamber 605 via the three way valve 606, flow predominantly to the external chamber 605.
On dispensing from the dispenser 607, the three way valve 606 changes alignment so as to dispense carbonated water from the top of the outer passage 609 while at the same time venting the accumulated gases in the external chamber 605 to atmosphere via the dispenser 607. The venting is achieved by flowing the carbonated water being dispensed through the chamber 605. This results in the chamber 605 being open to and fluidly communicating with the dispenser 607. Furthermore, the flow of carbonated water through the chamber 605 upon dispensing physically pushes at least a portion of the gas that has accumulated in the chamber 605, out of the chamber 605. This same dispensing causes carbon dioxide and water to enter the inner passage 608 so as to replenish the dispensed product. The three way dispensing valve 606 therefore allows for a controlled venting of extraneous gases which may build up in the vessel 604.
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Referring now to Figure 20, a similar plant 700 for producing carbonated water to the plant 600 is shown. However, for the plant 700 there is a fixed intervening gaseous space at the top of the inner passage 708. This fixed intervening gaseous space is created by the float valve 717. Furthermore, when at rest and not dispensing, the three way valve 706 allows gas to flow between the inner passage 708 and the outer passage 709 thereby creating the internal chamber 705 above the outer passage 709 due to the equilibration of liquid levels. When the three way valve 706 is aligned to allow for dispensing at the dispenser 707 the accumulated gases in the internal chamber 705 are vented to atmosphere via the dispenser 707. In some applications venting gas from the whole of the typically annular space of the internal chamber 705 above the outer passage 709 may be a greater volume than required. However, it is possible to vent gas from only a portion of the internal chamber 705 thereby reducing the volume of gas vented. Such a portion of the chamber may have continuous vertical surfaces with its lower open surface above the "at rest" water level so as to allow for free movement of gases from the remainder of the outer passage 709 above the water level. In a variation, the plant 700 may also have an external chamber similar to that of plant 600 so as to give greater flexibility to vary the effective venting volume on site. Varying the venting volume may enable minimization of carbon dioxide losses. The portion of the total chamber that is external to the vessel may be maximized by changing the configuration so as to have small diameter carbonated water product outlet tubing within a large diameter feed tube. In this variation, the carbonated water exits the vessel from the inner passage and the inflow of carbon dioxide gas and water is to the outer passage.
Also for certain three way valves, on change of
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valve alignment there may be a short period of time when all three ports are open. Consequently, when using such valves the top of the inner passages 608, 708 of the vessels 604, 704 may be in fluid communication with the dispenser 607, 707 for a short duration via the three way valve 606, 706. This may have an additional timed venting effect, by venting a portion of the vapour space above the inner passage 608, 708. Such a timed venting effect may, however, be achieved by other means as will be discussed further on in the specification.
Referring to both Figures 19 and 20, the inlet to the three way dispensing valve 606 and 706 from the inner passage 608, 708 may, in a variation, have a further on/off valve in the line (not shown) , which is responsive to the liquid level in the inner passage 608, 708 such as a further separate float valve or an ancillary valve function in the float valve 717 (in the case of plant 700) . The purpose of this on/off float valve would be to allow gaseous fluid communication between the inner passage 608, 708 and the chamber 605, 705 via the three way dispensing valve 606, 706 only when there is a high water level in the inner passage 608, 708 and when any extraneous gases are at a high concentration in the vapour space of the vessel 604, 704. This variation has particular relevance to a situation where more than one opening and closing of the three way dispense valve 606, 706 occurs in quick succession so as to serve consecutive drinks. In such a situation the liquid level in the inner passage 608, 708 may not have had sufficient time to return to a full level before the next drink is served. Consequently, any venting of a portion of such a gas above the lower liquid level in the inner passage 608, 708 via the chamber 605, 705 may not be as effective in removing extraneous gases and indeed be wasteful of carbon dioxide compared with the situation where the portion of the gas vented via the chamber 605, 705 came from a gaseous space above a high
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liquid level in the inner passage 608, 708.
Further, due to the variable effectiveness of venting extraneous gases as a result of varying liquid levels, a temporary build up of extraneous gases may occur in vessels with a fixed designed for vapour space such as vessel 704. If this fixed designed for vapour space is too small the pressure exerted by this temporary build up of extraneous gases may become too high and prevent an appropriate amount of carbon dioxide from entering the vessel 704.
However with an appropriately designed buffer volume for the fixed designed for vapour space of vessel 704 this temporary build up of extraneous gases may be maintained within acceptable levels and will have only a minor effect on the carbonation of the water. Furthermore the temporary build up of extraneous gases will be alleviated the next time the vessel is vented in association with a full level in the vessel 704.
The three way dispensing valve may be also used for dispensing from the top of a plurality of such passages in a vessel if required by creating a manifold at the top or side of such passages depending on whether the passages are aligned substantially vertical or horizontal. A three way dispensing valve in accordance with embodiments of the present invention is also applicable to dispensing from storage vessels such as the product drawdown vessel 106 of the plant 100 described above.
In certain other instances where flow is into the top, side or bottom of an elongated hose tank, the passages of which are oriented substantially horizontally or vertically a three way dispensing valve may not be required.
This is because the hose tank may have a plurality of passages of a small cross sectional area as compared with an equal capacity vessel of the type shown in Figure 19. At sufficiently low cross sectional areas, due to the fluid dynamics of the system, the accumulated
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gases can be made to flow with the flow of water into the next passage.
This is because there is a critical tube diameter at which a bubble will be held in place by the surface of the tube and will resist the tendency to rise in vertically aligned or partially vertically aligned tubing. This is due to surface tension. This critical tube diameter may vary slightly with the wetability of the tube surface but for many materials may be considered to be approximately 10 mm.
Any extraneous gases in the hose tank which do not dissolve in the water may accumulate in any number of chambers within the hose tank. For a hose tank having a tube with an internal diameter equal to or less than the critical diameter and also with substantially vertical passages these chambers may therefore not necessarily be located at the top of the hose tank where two adjacent passages meet but may be at an intermediate height due to surface tension. The accumulated gases in these chambers may therefore gradually move with the flow of dispensed carbonated water from passage to passage, not rising to the top of a passage when the flow stops and eventually to the dispenser. Consequently feed may be introduced even to the top of a downward flowing spiral hose tank and accumulated gases will eventually flow to a dispenser at the bottom of the spiral hose tank.
In this arrangement, the hose tank may not require a three way dispensing valve to vent the accumulated gases and an on/off dispensing valve will be sufficient.
In a further embodiment, the three way dispensing valve may also incorporate features known in on/off dispensing valves to minimize foaming or decarbonation on dispensing.
In another variation, the plants 600 and 700 may
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also comprise a second three way valve controllable by a fill signal from the vessel 604, 704. This second three way valve acts as an extra precaution against backflow of carbonated water in the plants 600 and 700 applicable where mains water is utilized as the pressurized feed 601 701.
Referring now to Figure 21, a plant 800 incorporating the above variation of the second three way valve is shown. The water level in the vessel 804 is controlled by a float switch 817 acting on the second three way valve 818 rather than the mechanical float valve 717 of the plant 700. The second three way valve 818 is preferably a solenoid valve. However, a mechanical three way valve such as a float operated spool valve or diaphragm valve may also be used. The second three way valve 818 is aligned such that the water upstream side of a check valve 812 in the rest position is in fluid communication with atmosphere via the second three way valve 818 when no power is applied to the solenoid. Consequently, at rest gaseous flow to atmosphere from the vessel 804 is prevented by the check valve 812. Additionally, in the rest position there is minimal chance of backflow of carbon dioxide into the feed still water, for if there is a break in the seal either side of the second three way valve 818 the flow will be to atmosphere. Furthermore, if this is within view of the consumer the flow (to atmosphere) especially of water will alert them that something is wrong. The other backflow mitigation measures such as the pressure differential valve 811, the buffer volume of the still water holding tank 802 and the check valve 815 will additionally act against backflow of carbonated water into the water supply.
The pressure differential valve 811, in addition to acting as a backflow mitigation measure also serves to appropriately regulate the carbon dioxide pressure in the vessel 804, by the selection of an appropriate pressure differential.
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It would be preferable if the carbonated water merely flowed smoothly on dispensing. The venting system may therefore also comprise a buffer volume 819 between the three way dispensing valve 806 and the dispenser 807 and a suitable diameter at the dispenser 807. This buffer volume 819 is to act against an unacceptable blast of pressurized gas exiting the dispenser 807 on dispensing. It is furthermore desirable that the line from the three way valve 806 to the dispenser 807 is well drained so as to avoid an aliquot of water being dispensed followed by a blast of gas and then the bulk of the carbonated water. This may be achieved by having the outlet of the three way dispensing valve 806 above the dispenser 807 and connected to it by substantially straight tubing of a suitable material and diameter.
To further achieve appropriate dispensing the venting system may also comprise a ball float valve 820 or any other similar such valve incorporating the features of valves generally known as "air release" or w air vent" valves. The ball float valve may have a vertical leg 821. Initially, the ball float valve 820 would loosely close off fluid communication with the dispenser 807 by gravity allowing vented gases out through the vertical leg 821, whereafter as carbonated water flowed through, the ball float would rise to close the vertical leg 821 and open fluid communication with the dispenser 807. The venting system may comprise flow channels from the top of the ball float valve 820 down to the dispenser 807 to cater for slight leakage of liquid from the upper seal of the ball float valve 820 during dispensing.
In a further variation the function of the three way dispensing valve 806 and the ball float valve 820 may be achieved by a single multiport valve (shown in later Figures) using separate gaseous and liquid flow paths. In this embodiment, a chamber which had been in fluid communication with the vapour space at the top of the inner passage 808 of the vessel 804 is isolated and then
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vented to atmosphere and simultaneously or sequentially liquid product flows to the dispenser. In this variation however water does not flow through the chamber as in the variation using the ball float valve. In a further variation of the plants 600, 700,
800 and in a configuration using a hose tank, the gas containing carbon dioxide and the water may converge in a mixing point before entry to the vessel 604, 704, 804 and the hose tank. This may achieve superior carbonation efficiency.
Figure 22 shows a plant 900 incorporating this variation. The carbon dioxide gas enters the water inlet to the vessel 904 via a mixing point 922 down stream of the check valve 912. Consequently, the carbon dioxide can enter the vessel 904 via this route whether water is flowing or not and thus enable the make up of any small leakage of carbon dioxide from the vessel when the plant is in the rest position. This is possible because the three way valve 918 which controls the flow of water into the vessel 904 is upstream of the mixing point 922.
Where no such valve exists such as for the plant 600 and plants utilizing a hose tank, the carbon dioxide may be prevented from entering the vessel 604 after the water has stopped flowing in because of the higher water pressure relative to the carbon dioxide pressure at the mixing point or within the vessel 604. This is due to the pressure differential valve 611.
This may be alleviated by additional valving such as a two position controllable on/off fill valve (not shown) in the water flow path upstream of the mixing point, which when closed in the rest position allows carbon dioxide to enter the vessel 604 or the hose tank.
Alternatively, where the on/off fill valve is downstream of any mixing point such as the float valve 717 of the plant 700, the additional valving may comprise a carbon dioxide two position controllable three way valve (not shown) which allows the carbon dioxide to enter the
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mixing point through one flow path of the carbon dioxide three way valve when the vessel is filling and then directly into the top of the vessel 704 via the other flow path of the carbon dioxide three way valve when the float valve 717 is closed.
The additional two position controllable valving may be part of a multifunctional valve and be activated by a water level or a timing signal. The timing signal may be at the end of a period initiated by the dispensing valve 606, 706 or the on/off dispensing valve of the hose tank.
The carbonated water produced in the plants 600, 700, 800, 900 may also be combined with syrups for the production of soft drinks. Plant 900 shows this variation. The combination of syrup and carbonated water may be made in a post mix manner whereby a syrup package 923 is pressurized by the regulated carbon dioxide gas pressure. On dispensing, this results in the three way valve 906 and the syrup valve 927 acting together in an appropriate way so as to deliver an appropriate quantity of syrup for mixing with the carbonated water from the vessel 904 through the post mix unit 928 to the dispenser 907. Carbonated water alone may also be dispensed through the dispenser 907 when the syrup valve 927 is closed. Alternatively, in a pre mix manner, a removable container 929 may be nominally filled with still water together with an appropriate quantity of syrup. The removable container 929 may then be sealed and brought into fluid communication with the regulated carbon dioxide pressure. The fluid communication may be via the vapour space of the removable container 929 only or via a sparger below the liquid surface. Fluid communication via the vapour space may take longer to achieve an acceptable product but would avoid turbulence created by the sparger. The vapour space of the removable container 929 may be purged of extraneous gases by at least one set of successive pressurizing and venting steps via a manually
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activated three port valve 930. A check valve 931 may be utilized to ensure extraneous gases from the removable container 929 do not flow back into the vessel 904. The liquid in the removable container 929 is then allowed to reach equilibrium with the vapour space, then sealed and removed.
The syrup package 923 on installation may similarly be purged of extraneous gases by at least one set of successive pressurizing and venting steps via a manually activated three port valve 932.
For the plants 600, 700, 800, 900 to function satisfactorily using pressurized mains water a suitable water pressure in the mains water supply needs to exist. A suitable water pressure in this regard is in the order of 3 bar.
In another variation to the embodiments shown in Figures 19-22, it is possible that a pressure regulator rather than the differential pressure valve could be used to regulate the carbon dioxide pressure from the pressurized carbon dioxide cylinder, and without the backflow mitigation afforded by the pressure differential valve but with other suitable backflow mitigation. A pressure regulator may also be used for configurations utilizing a break tank for water feed and a water pump. Referring now to Figures 25-29 there is shown further plants 1000, 1100, 1200, 1300, 1400 each comprising a water pump, a break tank and a carbon dioxide gas regulator.
Figure 25 shows a plant 1000 wherein water is pumped from a break tank 1034 via a water pump 1035 into the vessel 1004. Carbon dioxide gas flows into the vessel 1004 via the carbon dioxide gas regulator 1036. The pump 1035, preferably an electrically driven pump, is controlled by the float switch 1017 that is for maintainng a maximum water level in the vessel 1004. The float switch 1017 may be controlled by a single level or dual level probes .
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The break tank 1034 is fed with water from the discharge of the still water holding tank 1002 via a float valve 1037, although any other level control valve may be used in the break tank 1034. The float valve 1037 is for maintaining a substantially constant water level in the break tank 1034.
The break tank 1034 also incorporates a drain 1038 the connection of which to the break tank 1034 is at a level between the maximum design water level in the break tank 1034 and the level at which the water enters via the float valve 1037. This ensures an effective backflow mitigation for the plant 1000 via an air gap.
Where the plant 1000 is incorporated in a refrigerator, the drain 1038 may flow to the evaporator tray under the refrigerator (not shown) .
The drain 1038 is shown in Figure 25 as open to the atmosphere. However it may have an air filter or automatic drain outlet as described elsewhere herein, such as a buoyant ball sitting on a seat merely by gravity. Should an overflow situation arise the ball would float allowing the water out. Otherwise the ball would loosely sit on the seat minimizing contamination from the air.
The break tank 1034 further has a lid 1039 to avoid contamination of water in the break tank 1034 from the air. The break tank may also be made from or have an inner surface of an anti-microbial material.
The break tank 1034 also has a conduit 1040 from the vertical leg 1021 of the ball float valve 1020 to below the water level near the bottom of the break tank 1034. The bottom end of the conduit 1040 may have a diffuser (not shown) for reasons that will become apparent further on in the description.
The plant 1000 also comprises a minimum liquid level mechanism in the form of an automatic drain 1041 on the outlet of the vessel 1004 so as to maintain a minimum design water level on the outlet of the vessel 1004. This prevents the possibility of pressurised carbon dioxide
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blasting out through the dispenser 1007 on dispensing. Such a blast of gas is undesirable not only because it creates a startling and unpleasant effect for the user but also because it results in an uncontrolled loss of carbon dioxide gas (as opposed to the controlled loss via venting which additionally removes extraneous gases from the vessel) .
The automatic drain 1041 as shown in Figure 25, is merely a buoyant ball on a seat that seals by gravity and the pressure differential between the vessel 1004 and atmosphere. When the liquid level in the vessel 1004 is above the minimum liquid level of the vessel 1004, the ball floats above its seat, opening the outlet of the vessel 1004. This is inexpensive and while sealing may be imperfect it would mitigate at least somewhat a blast of pressurised gas at the dispenser 1007 on dispensing. However other automatic drains with superior sealing characteristics may be utilized including designs relying on lever arms and dynamic characteristics. A low level switch and a solenoid valve (not shown) may also be utilized to maintain a minimum design water level in the vessel 1004. Indeed any mechanism to prevent pressurised gases blasting through to the dispenser 1007 on dispensing from a low level, which does not rely on the volumetric flowrate capacity of pump 1035 to maintain water level, is preferable for plant 1000.
Prior carbonators implicitly rely on the volumetric flowrate capacity of the pump being greater than or at least approximately the same as the volumetric flowrate dispensing rate of the carbonated water for an acceptable operation. These prior carbonator devices may be considered adaptations of commercial post-mix carbonators rather than being specifically designed for a domestic refrigerator or other such smaller capacity use. In the plant 1000 shown in Figure 25, the pump
1035 has a volumetric flowrate capacity which is less than the volumetric flowrate of the dispenser, preferably much
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less than at the dispensing flowrate, such as a trickle (1-250 ml/min, preferably l-50mL/min) . Such a pump has particular advantage in relation to a refrigerator in terms of cost, space and complexity of the pump. The pump 1035 may for example be a peristaltic pump or any other suitable pump. Also, because of the low flowrate to the vessel, the incoming water to the vessel may be more fully carbonated and the dilution of the carbonated water already in the vessel 1004 is less. Thus, the product quality in the vessel is maintained as the vessel is being filled.
Furthermore, the effective venting procedures outlined herein also provide for a low pressure pump. The combination of a low volume/low pressure pump is especially advantageous for small use applications such as in a domestic refrigerator in terms of cost, space and complexity.
In these embodiments, consumer demand is satisfied primarily from the capacity of the vessel 1004 rather than the volumetric capacity of the pump 1035. The vessel 1004 being refilled at a low volumetric flowrate over the long period of time that product is not being dispensed, is typically sufficient given a sufficient volume in the vessel 1004. Such a low volumetric capacity pump combined with an automatic drain on the outlet of the vessel may result in carbonated water product being temporarily unavailable due to a low level in the vessel 1004 at certain times. However this may be acceptable in many consumer settings and the capacity of the vessel 1004 may be adjusted upward if necessary to meet expected demand.
During operation of plant 1000, on dispensing from the three way dispensing valve 1006, gases are vented from the external chamber 1005 via the vertical leg 1021 of the ball float valve 1020 and the conduit 1040 to below the surface of the break tank 1034. The vented gases are bubbled to the surface of the liquid in the break tank
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1034 possibly via a diffuser (not shown) . This allows for some recovery of the carbon dioxide from the vented gas into the water in the break tank 1034 which then may flow back into the vessel 1004 via the pump 1035. During operation of plant 1000 (in comparison to plant 800) , during the venting step there will be an additional head on the ball float valve 1020 equal to the head of water in the conduit 1040 below the water level in the break tank 1034. This will further act on the ball so as to seal fluid communication with the dispenser 1007 and is an extra force that the buoyancy of the ball (or other such member) of the ball float valve 1020 must overcome for the ball (or other such member) to shuttle from one seal to the other and so open fluid communication with the dispenser 1007. Other enhanced recovery methods are also possible as will be shown further on with reference to Figures 30-33
Figure 26 shows a similar plant 1100 to the plant 1000 of Figure 25 comprising a water pump 1135 and a break tank 1134. The plant 1100 has an alternate automatic drain 1141 with a float and lever arm. The plant 1100 also incorporates a two position multiport valve 1142 activated when dispensing from the vessel 1104 occurs. The multiport valve 1142 comprises a first on/off valve 1143 for dispensing carbonated water only together with a second on/off valve 1144 upstream of an external chamber 1105 and a third on/off valve 1145 downstream of the external chamber 1105 for the purpose of venting the external chamber 1105. The discharge port of the third on/off valve 1145 may flow through a check valve 1146 to atmosphere. The multiport valve 1142 may be a spool or pinch valve or other known valves incorporating a plurality of valving functions activated by a substantially single input. In the rest position the first and third valves
1143 and 1145 are closed and the second valve 1144 is open. The external chamber 1105 is therefore in fluid
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communication with the vapour space of the vessel 1104 and pressurised. On dispensing the first valve 1143 opens to dispense carbonated water while the second valve 1144 closes and the third valve 1145 opens. The external chamber 1105 therefore vents to atmosphere via the third valve 1145 and check valve 1146.
The check valve 1146 may not be necessary especially as the dispensing function is normally of short duration. It may nevertheless act to prevent the flow of extraneous gases back into the external chamber 1105 during venting. Such backflow may occur without the check valve 1146 due to the chamber 1105 being at atmospheric pressure at the end of the venting step and also because of the turbulence created by the venting step. Extraneous gases flowing back into the chamber 1105 will negate the venting process. The check valve 1146 may be substituted by a suitably long length of narrow diameter tubing which will also mitigate backflow of extraneous gases into the chamber 1105. In another embodiment the check valve 1146 is upstream of the external chamber 1105 between the vessel 1104 and the external chamber 1105. This also prevents backflow into the vessel 1104.
The venting may occur in the reverse order, that is with second valve 1144 open on dispensing and closed at rest, but this may be less effective.
In yet a further variation not shown in the Figures, the second valve 1144 is a solenoid valve controlled by the float switch 1117, although it may also be a float valve within the vessel 1104. In this embodiment the second valve 1144 would allow gaseous flow into the chamber, whether an internal chamber or an external chamber, only when there was a full or substantially full level in the vessel 1104. This full level may be indicated by a float switch 1117. By this variation the venting system is operated in association with a full or substantially full level in the vessel and the dispensing function. Notably, in this variation,
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venting may not occur on every dispensing of carbonated water from the vessel.
Figure 27 shows a further plant 1200 incorporating a different two position multiport valve 1242 activated on dispensing. The multiport valve 1242 comprises two on/off valves 1243 and 1247 which are both closed in the rest position and open on dispensing. There is also a restrictive orifice 1248 in the line connecting the inlet of valve 1247 to the vapour space of the vessel 1204. On opening of valve 1247 during the dispensing function the restrictive orifice 1248 serves to limit the venting of gases to an appropriate quantity. This is a timed venting effect whereby a portion of the chamber above the water level of the vessel 1204 is vented during the dispensing function. The restrictive orifice 1248 may be sized appropriately given the pressure within the vessel 1204 so as to vent an appropriate quantity of gas to atmosphere.
Figure 28 shows a further plant 1300 incorporating a venting system whereby an external chamber 1305 is vented on filling of the vessel 1304 rather than on dispensing from the vessel 1304. In the plant 1300 the float switch 1317 that controls the pump 1335 also controls a three way valve 1349, typically a solenoid valve. The three way valve 1349 vents the external chamber
1305 in a similar manner that the valves 1144 and 1145 vent the external chamber 1105 of plant 1100. It may be preferable that the plant 1300 has check valve 1346 to mitigate backflow of extraneous gases into the system particularly as the filling function is likely to be longer than the dispensing function hence providing more time for undesirable diffusion of extraneous gases into the plant 1300.
For plant 1300 the external chamber 1305 comes into fluid communication with the vapour space of the vessel 1304 when there is a maximum level in the vessel 1304 and is thereby filled when extraneous gases are at a
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high level in vapour space of the vessel 1304. Consequently there is a low loss of carbon dioxide associated with this embodiment.
Figure 29 shows yet a further plant 1400 comprising a different pumping arrangement. For the plant 1400 the pumping comprises a double acting diaphragm pump 1435 although it may be a double acting piston pump or other pneumatic pump.
The double acting diaphragm pump 1435 of the plant 1400 is powered by the pressurised carbon dioxide rather than being an electrically powered pump described previously. The pressurised carbon dioxide used to power the pump is derived from a take off downstream of the regulator 1436 via a three way valve 1450. The take off is also upstream of a check valve 1451.
The three way valve 1450 is either for directing the flow of carbon dioxide toward the double acting diaphragm pump 1435 when the vessel is filling or toward the vapour space of the vessel 1404 when the vessel 1404 is full so as to supply make up carbon dioxide gas. The three way valve 1450 is preferably a solenoid valve controlled by float switch 1417. The three way valve 1450 therefore acts to start and stop a filling cycle of the vessel 1404. The double acting diaphragm pump 1435 comprises two flexible diaphragms 1452, 1453 connected by a fixed connecting rod 1454. Each flexible diaphragm 1452, 1453 is disposed between respective first spaces 1455, 1456 which are in fluid communication with pressurised carbon dioxide gas and respective second spaces 1457, 1458 which are in fluid communication with water drawn from the break tank 1434. The pressurised carbon dioxide which powers the double acting diaphragm pump 1435 enters the first spaces 1455, 1456 via a toggle valve 1459. The carbon dioxide gas is also exhausted from the first spaces 1455, 1456 via the toggle valve 1459.
When one of the first spaces 1455 is pressurised,
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the alternate first space of the first spaces 1456 is exhausted, causing the connecting rod 1454 to travel towards the first space 1456 being exhausted. Near the end of the travel of the connecting rod 1454 a toggle mechanism associated with the connecting rod 1454 and the toggle valve 1459 arranges the toggle valve 1459 so that the exhausted first space 1456 comes into fluid communication with the regulated pressurised carbon dioxide gas. This forces the connecting rod in the opposite direction. Consequently a pumping action is generated.
The double acting diaphragm pump 1435 is therefore a metering pump and pumps a given quantity of water per quantity of gas. By selecting the pressure of the regulator 1436 the ratio of water to carbon dioxide may be varied. At a regulator pressure of 4 bar approximately four volumes of carbon dioxide will be pumped by the double acting diaphragm pump per volume of water. This is the required ratio for an acceptable carbonated water product. The three way valve 1450 acts to allow carbon dioxide gas into the vessel 1404 only via the double acting diaphragm pump 1435 during filling and not via check valve 1451. Thereby excess carbon dioxide gas is not added to the vessel 1404 and the performance of the double acting diaphragm pump 1435 is improved.
A suitable pressure differential also needs to be created between the regulated gas pressure which powers the double acting diaphragm pump 1435 and its exhaust pressure in order for the double acting diaphragm pump 1435 to operate effectively. As the gases are not wasted to atmosphere but recovered in the vessel 1404 a back pressure exists in the vessel 1404 against which the double acting diaphragm pump 1435 must pump. The above four volumes of carbon dioxide will, at equilibrium, dissolve in the metered amount of water at 3 bar in the vessel 1404. Consequently a potential suitable pressure differential of 1 bar exists to power the double acting
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diaphragm pump 1435. However this is without the presence of extraneous gases. The presence of extraneous gases detracts from this pressure differential and when the extraneous gases exhibit 1 bar pressure there is no potential pressure differential to power the double acting diaphragm pump 1435. It is therefore necessary to have the extraneous gases at a low level preferably well below 1 bar in the vessel by venting the vessel 1404 according to other embodiments mentioned herein. It should be noted the check valve 1451 in this embodiment not only serves to maintain the integrity of the upstream carbon dioxide gas as for similar previous embodiments herein but also has a substantial cracking pressure in the order of 1 bar so as to maintain the appropriate pressure differential between the vessel 1404 and the regulated pressure powering the double acting diaphragm pump 1435.
The exhausted gas and water may exit the double acting diaphragm pump 1435 separately so as to flow preferably via check valves into the vessel 1404 (not shown) or may be mixed at a mixing point prior to entry to the vessel 1404. However for the plant 1400 the water and carbon dioxide combine in a premixing vessel 1460, before entry to the vessel 1404. By dissolving in the water in the premixing vessel 1460 the pressure of the carbon dioxide gas in combination with the water is reduced (at the temperature of 4 0 C) as compared to in the undissolved state. This volumetric contraction assists in the pressure differential required by the double acting diaphragm pump 1435 to pump into the vessel 1404. Furthermore, the volumetric contraction is more rapid when the dissolution is in pure water as in the premixing vessel 1460 as compared to being added separately to the already highly carbonated water in the vessel 1404. Also for plant 1400 there is shown a separate venting system. This is similar to the venting system of the plant 1200 of Fig. 9 but rather than having a
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restrictive orifice 1248 in the venting line, the plant shown in Figure 29 comprises a restrictive device which is a check valve 1461 with a cracking pressure less than the equilibrium pressure of the vessel 1404 in the rest position.
It is also noted that for the plants 1100, 1200, 1300 and 1400 the water need not enter and leave the vessel 1104 via opposing flow paths.
Furthermore it is noted the vessel 604-1404 and its connections should be made of a material impervious to gases or at least with a low permeability to gases.
In a further embodiment Figures 30 and 31 show a means to recover carbon dioxide from the vented gases (however produced) as an alternative arrangement to bubbling the gases through the break tank 1034 as in the plant 1000 shown in Figure 25.
For Figures 30 and 31 an inverted bucket 1562 is placed within a break tank 1534. The inverted bucket 1562 has a top 1563 which is closed except for a small orifice 1564 and an open bottom 1565. The small orifice 1564 in the top of the inverted bucket 1562 mates with a fixed sealing member 1566 attached essentially rigidly to the break tank 1534. The small orifice 1564 and the fixed sealing member 1566 therefore constitute a valve. The inverted bucket 1562 sits within a sleeve 1567 on footings 1568. The sleeve 1567 and footings 1568 are further supported by a fixed perforated base 1569 rigidly attached to the break tank 1534.
For Figures 30 and 31 vented carbon dioxide gas from the plants 1000 1100 1200 1300 1400 for example flows into the top 1563 of the inverted bucket 1562 by a flexible connection 1570. However it may also be introduced to the open bottom 1565 of the inverted bucket 1562 but preferably above the top of the perforated base 1569 and the pump inlet 1571.
For Figures 30 and 31 the top 1563 of the inverted bucket 1562 is shown above the water level in the
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break tank 1534 although it may also be below the water level at any part of a cycle.
Figure 30 shows the position of the bucket 1562 when the plant is at rest after a sufficient time since the last dispensing. The weight of the inverted bucket
1562 has caused it to rest on its footings 1568. In this position the small orifice 1564 and the fixed sealing member 1566 are disengaged and the vapour space of the inverted bucket 1562 is in fluid communication with the atmosphere via the small orifice 1564 and either the drain 1538 or the lightly sealed lid 1539.
When the vented gases pass through the top 1563 of the inverted bucket 1562 the rate of flow of the gases is such that they cannot escape quickly enough through the small orifice 1564 and accumulate in the top portion of the inverted bucket 1562. The buoyancy thereby created lifts the inverted bucket 1562 off its footings 1558 and linearly directed by the sleeve 1567 the small orifice 1564 mates with the fixed sealing member 1566 as shown in Figure 31. This prevents any further loss of vented gases to atmosphere. The vented gases thereafter accumulate in the inverted bucket 1562 and push the water level 1572 in the inverted bucket 1562 down while pushing the water level 1573 in the break tank 1534 up as shown in Figure 31.
The break tank 1534 will therefore be 'overfull' as shown in Figure 31 by comparison with Figure 30. That is the water level 1573 in the break tank 1534 will be higher than the equilibrium water level determined solely by the float valve 1537. Consequently no water will flow into the break tank 1534 via the float valve 1537 until the pump 1535 or dissolution of the vented gases in the water in the break tank 1534 reduces the water level 1573 in the break tank 1534 to the appropriate level. The drain 1538 and the level at which water enters the break tank 1534 should be sufficiently above the 'overfull' level in the break tank 1534 to ensure
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water does not as a normal part of the cycle overflow via the drain 1538 or breach the air gap associated with the required water backflow prevention as previously described. The check valve 1574 ensures backflow of vented gases does not occur from the inverted bucket 1562 such as via the ball float valve 1020 and the dispenser 1007 of plant 1000 once dispensing stops. However it is possible the ball float valve 1020 itself may provide some backflow mitigation.
As the carbon dioxide within the inverted bucket 1562 dissolves in the water, the water level 1572 in the inverted bucket 1562 rises. Eventually the buoyancy in the inverted bucket 1562 is lost and the fixed sealing member 1566 disengages from the small orifice 1564. The fluid communication that results between the inverted bucket 1562 and the atmosphere via the small orifice 1564 prevents the accumulation of extraneous gases in the inverted bucket 1562 over continued cycles. The inverted bucket 1562 may preferably have a volumetric capacity consistent with the venting associated with one or two drinks though it may be larger. Any excess volumetric venting will pass out through the perforated base 1569 and bubble to the surface. The inverted bucket 1562 may form a considerable volumetric portion of the break tank 1034 leaving only the necessary passage way for bubbles to readily migrate to the surface. By this means carbon dioxide recovery may be enhanced. This is because this will maximize the time before water flows again into the break tank 1534 via the float valve 1537 and dilution occurs.
In a further embodiment shown in Figures 32 and 33 the inverted bucket 1662 is fixed to the perforated base 1669 which is rigidly fixed to the break tank 1634. The inverted bucket 1662 is therefore in a fixed position and not buoyant. Furthermore the inverted bucket 1662 does not have a small orifice in its top and there is no need
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for a fixed sealing member or a sleeve. The vented gases may be vented into the top or bottom of the inverted bucket 1662 in a similar manner as into the inverted bucket 1562 though there is no need for a flexible connection. However for Figures 32 and 33 the gases are vented into the top of the inverted bucket 1662. The inverted bucket 1662 may similarly have a portion above the water level or be totally below the water level in the break tank 1634 at any part of the cycle. The accumulation of extraneous gases in the inverted bucket 1662 may be prevented by their dissolution in the water or by successive venting steps eventually breaching the bottom of the inverted bucket 1662 with gases bubbling to atmosphere through the perforated base 1669.
The accumulation of extraneous gases in the inverted bucket 1662 may also be prevented by the inverted bucket 1662 or its connections 1670 being of a gas permeable material. The permeation rate would preferably be such that minimal carbon dioxide gas is lost via permeation during the relatively short filling time but that for an extended period at rest, sufficient permeation would occur. This would be driven by a pressure differential due to a higher water level in the break tank 1634 compared with the lower water level inside the inverted bucket 1662 as a result of the accumulation of extraneous gases .
The above embodiments showing an inverted bucket 1562, 1662 in a break tank 1534, 1634 may also be extended so as to incorporate an inverted bucket into a cool water reservoir such as the cool water reservoir 107 described above .
Referring to Figures 19-33 in each of the plants 600-1400 the vessel 604 - 1404 is simple in structure. It would be desirable to place it at a convenient location in the refrigerator where the contents would remain cold, such as at the back and bottom of the refrigerator next to
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still water holding tank 602, 702, 802 etc. However, given that the carbon dioxide container 603, 703, 803 etc. and various valves are preferably located in close proximity to the vessel 604 - 1404 such a location does not provide easy access to the consumer and typically involves removal of shelving to change cylinders and adjust valves.
A preferable location for the vessel 604 - 1404 would be in the door of the refrigerator. However, this is not the coolest location in the refrigerator especially with opening and closing of the refrigerator door.
However, by insulating the upper portion of the vessel 604 - 1404 and having a lower portion near the bottom of the vessel 604 - 1404 made of a heat conducting material and placed in the air space near the bottom of the refrigerator the vessel 604 - 1404 may be cooled appropriately. This is because the air space near the bottom of the refrigerator is sufficiently cool. A reason for this is that many refrigerators have crisper bins located in the bottom of the "above freezing" fresh food section of the refrigerator and cold air is directed under these crisper bins so as to keep their contents colder than the remainder of the refrigerator. Also the colder air being more dense tends to remain at the bottom of the refrigerator.
The lower heat conducting portion of the vessel may further have finned heat conducting protrusions 1775 in the air space at the bottom of the refrigerator as shown in Figure 34. These fins allow a pathway for the substantially upward flow of air so as increase heat transfer arising from natural convection. This may be achieved for example by the finned heat conducting protrusions 1775 being horizontal with holes 1776 as shown in Figure 34. Furthermore, so that the rise of air is not impeded by a horizontal flat bottom of the vessel 604 - 1404 the bottom of the vessel may be tapered 1777. Alternatively the finned protrusions 1775 may project out
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horizontally from the vertical projection of the vessel. This is preferably toward the inner portion of the refrigerator. However, a spatially effective means of achieving this may comprise a cylindrical vessel 604-1404 having square finned protrusions 1775 as shown in plan view in Figure 35.
The lower heat conducting portion may be advantageously achieved, for example by a metallic "screw in" bottom (plug) into a polymer vessel 604 - 1404. The lower heat conducting portion of the vessel 604 - 1404 may further comprise heat conducting protrusions up into the vessel 604 - 1404. These protrusions may also have a secondary function as a baffle so as to direct flow transverse to the main flow in the inner passage 608, 708, 808, 908, etc so as to avoid short circuiting of flow in the inner passage 608, 708, 808, 908, etc.
While the above cooling features are especially desirable when the vessel is placed in the door of the refrigerator, they are also applicable if the vessel is placed elsewhere in the refrigerator such as at the rear of the refrigerator.
Prior carbonators located in the door of a refrigerator have been smaller than the vessels 604 - 1404 indicated in the layout shown in Figure 23. Such prior carbonators have required expensive cooling means to adequately cool the water as it flows through the carbonating vessel. However, because of the larger size of the vessel 604-1404 once cooled such as by the method outlined above it is resistant to warming due to the high heat capacity of water and the larger volume of water in the vessel 604-1404. It therefore does not require such expensive cooling means.
Furthermore, the low flowrate of water into the vessel from the low volumetric flowrate pump 1035 does not impose a high heat load on the vessel 604-1404 caused by the mixing of the carbon dioxide and water.
In another embodiment the vessel 604 - 1404 is
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housed within a specially refrigerated and insulated compartment within the door of the refrigerator. This may be in the door of the "above freezing" fresh food section of the refrigerator or for a side by side refrigerator, for example, may be in the freezer door in which a combined cold still water dispenser and ice dispenser is typically located.
The specially refrigerated and insulated compartment may be maintained at the correct temperature by flowing air over the evaporator within the freezer and then through the specially refrigerated and insulated compartment in an appropriate way and with appropriate dampening control as is common for maintaining a correct temperature in other sections of the refrigerator. An added advantage of having the vessel 604 -
1404 and the dispensing valve 606, 706, 806, etc in the refrigerator door is that the recess in the door in which the dispenser 607, 707, 807, 907 for serving the drinks is located not far from the dispensing valve 606, 706, 806, 906. Consequently a dedicated carbonated water line is possible rather than a common line with still water from the back of the refrigerator, which may cause dilution of both water streams. Also, the three way dispensing valve 606, 706, 806, 906 etc., is readily placed above the dispenser 607, 707, 807, 907 etc. Furthermore, any malfunction of equipment resulting in a leakage flow to atmosphere as designed for in the backflow mitigation system will be in view of the consumer. While the carbon dioxide feed 603, 703, 803 etc. in the form of a cylinder is also shown within the refrigerator such as in Figure 23 for example it may also be placed outside the refrigeration space.
Figures 23 and 24 indicate a possible layout for the plant 600 - 1400 in a refrigerator. Shown therein is a valve or pump housing 633 - 1433 as a possible location for the various valves or pump of the plant 600 - 1400.
The break tank 1034 - 1634 may also be placed in
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the door of the refrigerator, preferably in close association with the vessel 1004 - 1004. It may also have an insulated upper portion and a lower heat conducting portion. Also, with the vessel placed in the door of the refrigerator there will be turbulence at the water level as the door is open and closed. For those plants utilizing a pump such as plant 1000 it is therefore preferable that the pump 1035 be started and stopped by dual level sensors located in an upper portion of the vessel. The difference in the level of the sensors would be suitably greater than the difference in the water level created by the turbulence. This would avoid the pump 1035 turning on and off needlessly due solely to the turbulence. Another means to protect against surface turbulence may involve housing the level sensor 1017-1417 in a buffering container (not shown) . The buffering container may have an open top above a maximum turbulent surface and a closed bottom suitably below a full, but turbulent minimum, water level, except for a small hole or labyrinth channel. There may be a suitable small wall clearance between the level sensor 1017-1417 and the buffering container. This may also mitigate surface turbulence to which the level sensor 1017-1417 might be exposed.
In another embodiment, the space allocated to the vessel 604-1403, pump/valve housing 633-1433, and cylinder 603-140 as shown in Figure 23 may have a dual purpose use. This is to allow the consumer the option to readily allocate the space to alternative foodstuffs at any time if they longer need the carbonation plant 100-1400.
This may involve the vertical space occupied by the plant 600-1400 as shown in Figure 23 being comprised of substantially vertical compartments with removable shelves and doors for example.
Alternatively, the full width shelves of a normal refrigerator may be maintained with removable or
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adjustable bottom portions of the horizontal shelves. These removable or adjustable portions would preferably be at the hinging end of the door so as to allow the location of the plant as shown in Figure 23. Such removable or adjustable (slidable) shelves or bottom portions and compartment doors may be adjusted appropriately to allow for removal or installation of the plant 600-1400 according to particular preferential use of the consumer. While the above embodiments are applicable to a domestic refrigerator they may also apply to other devices for dispensing carbonated water such as a water cooler.
Embodiments of the present invention also relate to a rotary pinch valve housing a plurality of flexible tubes.
The rotary pinch valve of the present invention may be adapted to discrete settings, where rotation is stopped either manually or by other means, after the rotating mechanism has passed through a particular angulation.
However the rotary pinch valve of this invention is more particularly applicable where it is desired to produce fluid flow through a plurality of tubes in a particular sequence so as effect an automated processing outcome in a piece of equipment or other such use and preferably where the rotation is driven by an essentially constant speed device such as by an electric motor.
As such, the rotary mechanism of the rotary pinch valve, will usually be a rotating cam surface. The full processing cycle will normally be defined by an angular rotation of 360 degrees of the rotating mechanism of the rotary pinch valve.
Patents US 3,506,032, US 3,918,490, US 4,282,902, US 5,113.906 indicate rotary pinch valves featuring a plurality of flexible tubes. However, these rotary pinch valves are intended for devices requiring essentially discrete positioning, such as manual laboratory apparatus,
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where the rotation is halted once a desired position has been reached. Furthermore the angle of rotation of the rotating mechanism, to induce a change of valve state from open to closed or vice versa is rather large, as indicated by the cam surfaces shown in the figures of the above patents.
This large angle of rotation to induce a change of valve state is not a problem where three or four discrete positions are required for such apparatus, as may be achieved manually or even by a stepper motor. However for an automated device driven by a constant speed motor it is often desirable that a change of valve state, as from open to closed or closed to open, occur over as small an angle as possible. This allows as much of the angular cycle and as a consequence time, to be devoted to flow through the respective tubes so as to enact their function. Angular rotation and thus time devoted to a change of valve state is effectively wasted time. This can become especially important as the number of flexible tubes increase, together with the requirement, for example, for some valves to shut before others close.
Patents US 4,457,339 and US 4,694,861 describe two further rotary pinch valves designed for a plurality of tubes, again mainly for a laboratory setting, driven by stepper motors and intended to be easily reprogrammable. US 4,457,339 has a limitation on the number of tubes capable of being handled as noted by US 4,469,861, which itself, while being highly programmable, is a complex and expensive device requiring a microcomputer controller. The rotary pinch valve of the present invention therefore seeks to provide a rotary pinch valve suitable for a plurality of tubes, as might be required by an item of equipment requiring a particular sequencing of flows to be enacted for an automated cycle and preferably using a constant speed driver or a stepper motor.
Such a valve has advantage in terms of cost and simplicity where an essentially fixed flow regime is to be
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enacted over a large number of cycles without the need to reprogram for varied flow regimes . However the rotary- pinch valve of the present invention may be designed to be reprogrammed, but this is by mechanical means. Now a particular embodiment of the rotary pinch valve of the present invention is shown in Figure 36. Therein the rotary pinch valve 1801 comprises a rotor 1802 a stator 1803 and a plurality of flexible tubes 1804 aligned parallel to the axis 1805 of the rotary pinch valve 1801.
The stator 1803 further comprises for each particular flexible tube 1806, a pinch slot 1809 and a rigid backing member 1810 supported by radial struts 1811. A movable member 1812 is located within the pinch slot 1809 and when activated moves to pinch the particular flexible tube 1806 against the rigid backing member 1810. Figure 36 shows, for illustration, but one such pinch slot 1809, movable member 1812 and rigid backing member 1810 for a particular flexible tube 1806. However each aligned flexible tube of the plurality of flexible tubes 1804 will require its own pinch slot, movable member and rigid backing member. Consequently a plurality of pinch slots are staggered around the circumference of the stator 1803 as well as along its axial length, one variation of which is shown in Figure 37. A particular flexible tube 1806 also has flexible tubes 1807 and 1808 either side of it except for a particular flexible tube at the periphery.
Referring now to Figure 36 the stator 1803 also comprises an end plate 1813 with alignment holes 1814 which are separated by alignment gaps 1815. This is matched by a similar set of alignment holes 1816 and alignment gaps 1817 at the other end of the stator 1803. The stator 1803 also comprises an internal cylindrical annulus 1818 into which the essentially cylindrical rotor 1802 is placed with a close tolerance. The end plate 1813 is removable from the stator 1803 so as to allow the essentially cylindrical rotor 1802 to be fitted into the
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internal cylindrical annulus 1818. The diameter of the hole 1819 in the end plate 1813 is less than the diameter of essentially cylindrical rotor 1802. The end plate 1813 when fixed in place therefore maintains the rotor 1802 in axial position.
Referring now to Figure 38 and Figure 39 the rotor 1802 comprises essentially circular cam disks 1820 each with a particular cam surface 1821 separated by cam spacer disks 1823 and held together in an essentially cylindrical whole. Each cam disk 1820 of the rotor 1802 interfaces with a particular pinch slot 1809 and movable member 1812 all of which are within in a particular pinch plane 1822 so as to act on a particular flexible tube 1806. The cam spacer disks 1823 are placed between consecutive cam disks 1820 such that, given the tolerances available, a particular movable member 1812 is acted upon by only the intended cam disk 1820 in its pinch plane 1822 and is not acted upon by an unintended adjoining cam disk. The cam spacer disks 1823 therefore may have a radius equal to or less than the smaller radius of the cam disk 1820. The pinch slots 1809 in the stator 3 are also effectively placed to mate with the corresponding cam disk 1820 and so take account of the cam spacer disks 1823 in the rotor 1802. This may be achieved by stator spacer disks (not shown) which are the same thickness as the cam spacer disks 1823 and in the same plane.
Referring now to Figure 40 there is shown a cross section through a particular pinch plane 1822 so as indicate the pinch mechanism. Therein the movable member 1812 is shown to be acted upon by a pair of springs 1824 which are supported by a spring compression base 1825 associated with the stator 1803 within the pinch plane 1822. The springs 1824 are also supported at their other end by lateral protrusions 1829 of the movable member 1812. The springs 1824 are to return the movable member
1812 to a position corresponding to an open state for the particular flexible tube 1806, when allowed to by the
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rotating cam disk 1820. The natural resiliency of the tubing may be sufficient to return the movable member 1812 back to the open position, in which case the springs 1824, the spring compression base 1825 and lateral protrusions 1829 may not be required. This is especially true under conditions when the flexible tube carries fluid under pressure. However where the fluid is under vacuum the springs 1824 may be preferable.
Also shown in Figure 40 are the radial struts 1811 which support the rigid backing member 1810. These radial struts 1811 encompass and align within the pinch plane 1822 the flexible tubes 1807 and 1808 either side of the particular flexible tube 1806 which is acted upon by a particular movable member 1812. Its is noted from Figure 40 there is a space between the particular flexible tube 1806, and adjoining flexible tubes 1807 and 1808 at an axial position where none are pinched. This space corresponds to the alignment gap 1815 between the alignment holes 1814 in the end plate 1813. However by appropriate selection of the alignment gap 1815 this space between the particular flexible tube 1816 and adjoining flexible tubes 1807 and 1808 may diminish almost completely when the particular flexible tube 1806 is pinched by the movable member 1812 and so spreads its width. Also by ensuring the adjoining flexible tubes 1807 and 1808 are pinched a suitable distance along the axial length of the stator 1803 to where the pinched particular flexible tube 1806 has returned to its unpinched diameter either upstream or downstream, it follows that any flexible tube of the plurality of flexible tubes 1804 where pinched within a pinch plane 1822 will be axially adjacent to two flexible tubes which are exhibiting an unpinched diameter within that same pinch plane 1822.
Consequently the rotary pinch valve 1801 can be made to be compact with a distance between adjoining unpinched flexible tubes being essentially half of the difference between the pinched and unpinched width of the
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particular flexible tube 1806. This does not take into account the slight curvature of the surface of the stator 1803 on which the plurality of flexible tubes is placed.
Furthermore referring now to Figure 41 there is shown a cross section through the stator 1803 which indicates aligners 1826 for the particular flexible tube 1826. These aligners 1826 which are not shown in Figure 36 are to avoid the particular flexible tube 1806 moving laterally. This essentially fixed lateral position allows the particular flexible tube 1806 to be pinched by a compact sized movable member 1812 the long edge of which in the pinch plane 1822 is approximately the same length as the pinched width of the particular flexible tube 1806. The aligners 1826 are placed at an appropriate short distance upstream and downstream of the pinch slot 1809 where the particular pinched flexible tube 1806 returns to its unpinched diameter. The aligners 1826 may be advantageously incorporated into a stator spacer disk with a cross section as shown in Figure 41.
Furthermore the aligners 1826 for the particular flexible tube 1806 are axially aligned in the gap between the unpinched flexible tubes 1806 and 1807 as well as the gap between flexible tubes 1806 and 1808 as shown in Figure 41. The particular flexible tube 1806 is also axially aligned by the alignment hole 1814 in the end plate 1813 as well as by the radial strut corresponding with the rigid backing member of another flexible tube
It follows that there is a series of passages parallel with the axis 1815 of the stator 1813 and in line with the alignment gaps 1815 where aligners 1826 and radial struts 1811 associated with any pinch slot 1809 may be placed. This equally leaves a separate series of parallel passages down the stator 1803 in line with the alignment holes 1814 for unimpeded passage of the plurality of flexible tubes 1814.
Furthermore a pinch slot 1809 may have an exposed
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long edge within a pinch plane 1822 that extends across the axial passage of its particular flexible tube 1806 and preferably fully or almost fully into the adjoining axial passages of the two aligners 1826 of that particular flexible tube 1806.
This exposed long edge of the pinch slot 1809 is also essentially the same length as the long edge of the pinching surface of movable member 1812 and is chosen to be essentially the same length as the pinched width of a particular flexible tube 1806.
Consequently by proper selection of the alignment gaps 1815 as shown previously not only the particular flexible tube 1806 but also the movable member 12 may almost touch the adjacent unpinched flexible tubes 1807 and 1808 when the movable member 1812 is extended to pinch a particular flexible tube 1806.
In other embodiments the radial struts 1811 may encompass more than three adjoining flexible tubes or less than three adjoining flexible tubes such as for peripheral flexible tubes. Furthermore the radial struts 1811 need not be fully radial but rather project appropriately outward from the stator 1803.
Also the pinching surface of the movable member 1812 as shown in Figure 36 is rectangular. In other embodiments the long pinching edges of this pinching surface may be rounded so as to minimize cutting or shearing of a particular flexible tube 1806.
Referring now to Figures 39 and 40 it is noted the curved surface of the movable member 1812 interfaces with the curved surface of the cam disk 1820. This is designed to deliver an abrupt change in valve state over as small an angle of rotation as possible. The design of optimal interfacing cam surfaces to achieve such an abrupt change would be known to those skilled in the art. However a cam angle approximating 45 degrees on the cam surface 1821 which may also be curved at the outer edge so as to avoid a point, together with a curved surface
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approximating a semicircle for the bottom of the movable member 1812 is determined to deliver such an abrupt change. It may be that more abrupt changes are possible as with greater angles than 45 degrees and with other curved surfaces on the movable member 1812 such as elliptical section shapes. It is desirable that the change of valve state from fully open to fully closed or vice versa can occur over as small a rotational angle as possible as from 5 to 15 degrees, for example. However this is ultimately dependent on the movement required of the movable member 1812 which is itself dependent on the diameter and wall thickness of the particular flexible tube 1806 as well as on the diameter of the rotor 1802 which is itself a function of the physical space allocated to the rotary pinch valve 1801.
This is to be clearly contrasted, however, with other known rotary pinch valves as noted above, where no emphasis has been placed on minimizing angular rotation of the rotor of the rotary pinch valve so as to induce a change of valve state.
Referring now again to Figure 36 it is noted that the stator 1803 of the rotary pinch valve 1801 is truncated. That is it is not cylindrical and has flat sides. However in another embodiment the stator 1803 may be fully cylindrical thereby allowing the plurality of flexible tubes 1804 to be placed fully around its circumference. However by close spacing a given number of flexible tubes of a certain diameter around the full circumference, depending on the number of tubes and their diameter, the diameter of the rotor 1802 may become excessively small. This could negatively influence the change of valve state sensitivity of the valve which is effectively proportional to the diameter of the rotor 1802. By truncating the stator 1803, the diameter of the rotor 1802 is maximized for a given number of flexible tubes of given diameter and physical spatial depth, in which to physically fit the rotary pinch valve 1801
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corresponding to the truncated width of the rotary pinch valve 1801. The larger the diameter of the rotor 1802 the smaller the angle that is required for a change of valve state, other factors remaining equal. Referring also to Figure 36 it is noted the cam surface of the rotor 1802 is internal to the stator 1803. However in another embodiment it may also be external to the stator and rotate around the stator.
Referring again to Figure 36 a desirable feature of the rotary pinch valve 1 is the external access to the plurality of flexible tubes 1804 which facilitates loading and replacing ruptured tubing. It is similarly desirable to be able to externally load the movable members 1812 and/or their associated springs 1824 into the respective pinch slots 1809 from the outside of the rotary pinch valve 1801 as loading from within the cylindrical annulus 1818 presents handling difficulties.
The loading of the movable member 1812 and/or associated springs 1824 into the stator 1803 is preferably done after the rotor 1802 has been placed inside the stator 1803 and before the plurality of flexible tubes 1804 are threaded into the stator 1803. This may be done by a number of means .
Referring to Figure 40 but also to Figures 42 and Figure 43 one means is to have an indentation 1827 either upstream or downstream of the pinch slot 1809. The indentation 1827 therefore will be associated with a different pinch plane (s) to that of pinch slot 1809. Thereby the movable member 1812 may be loaded into the indentation 1827 and slid axially and under the rigid backing member 1810, at which stage the flat pinching surface of the movable member 1812 will be flush with the bottom of the rigid backing member 1810 (Figure 42) . Also the lateral protrusions 1829 of the movable member 1812 may preferably fit just under the spring compression base 1825. The movable member 1812 may then be lowered into pinch slot 1809 (Figure 43) . The springs 1824 may then be
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loaded possibly with a tool whereafter an indentation filling piece (not shown) may be fixed in the axial upstream or downstream indentation 1827, especially in the instance where springs 1824 are utilized, so as to provide a backing surface for the springs 1824 and also for the movable member 1812.
However where no springs 1824 are utilized, an indentation filling piece may not be required, as the movable member 1812 will be held in correct alignment by the stator 1803 as the movable member 1812 is advanced into the stator 1803 over the loading position, by a distance equivalent to that taken up by the flexible tube 1806. Such a condition is shown by comparison of Figures 44 and 45. Figure 44 shows the movable member 1812 ready to be loaded into the pinch slot 1809 and Figure 45 shows the movable member 1812 loaded into the pinch slot 1809. The movable member 1812 is prevented from wobbling axially by the axial width of the movable member 1812 fitting into the pinch slot 1809 with close tolerance. Also while no springs 1824 or spring compression base 1825 are utilized in this embodiment the lateral protrusions 1829 of the movable member 1812 are preferably maintained and so effectively increase the effective length of the movable member 1812 loaded into the stator 1803 when a particular flexible tube 1806 is pinched. This increased effective length loaded into the stator 1803 also acts to keep the movable member 1812 properly aligned in the pinched condition.
In another embodiment not shown in the Figures, the rigid backing member 1810 and radial struts 1811 together with the spring compression base 1825 may be made into a single latching piece (not shown) which latches into attachments on the stator 1803. This latching may be by a number of means including pin like fasteners through holes in the latching piece and mating holes in the stator 1803 or via circlips, for example. Thereby the said latching piece may be fitted and removed from the stator
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as required. When the said latching piece is removed the movable member 1812 and springs 1824 may be loaded into the pinch slot 1809 from above and the latching piece then attached to the stator 1803. In this embodiment the indentation 1827 will not be necessary.
In a variation, the abovementioned latching piece latches at only one point in the stator 1803 and is rotatable within the pinch plane 1822 about another point on the stator 1803. Unlatching the rotatable latching piece thereby allows the movable member 1812 and springs 1824 to be loaded in the pinch slot 1809 whereafter the latching piece is rotated to latch into the stator 1803.
Another desirable feature of the rotary pinch valve is that ruptured tubes may be removed when desired. It may be that a particular flexible tube 1806 is in the closed position when the motor has stopped with the movable member 1812 protruding from the stator 1803 as indicated in Figure 36 and it is not practical to restart the motor. With the rigid baking member 1810 in a permanent fixed position relative to the radial struts 1811 the pinched flexible tube 1806 will therefore be difficult to remove as will loading of a new flexible tube. However if the rigid backing member 1810 is removable from the radial struts 1811 or rotatable around them, then a ruptured particular flexible tube 1806 can be removed and a new particular flexible tube 1806 placed in position over the protruding movable member 1812 and then the rigid backing member 1810 may be compressed into position. This may be achieved with the rigid backing member 1810 being a part of the aforementioned latching piece or with the rigid backing member 1810 being removable or rotatable as a separate individual piece.
For example, the radial struts 1811 may also be made to flex such as by spring steel within the pinch plane 1822, so that a mating rigid backing member 1810 as an individual piece may be fitted into and removed from
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the radial struts 1811 by flexing the radial struts 1811. The rigid backing member 1810 as an individual piece may also rotate and latch in the pinch plane 1822 in a similar manner to the aforementioned latching piece with the exception that it rotates about and latches into the radial struts 1811.
In a further variation, the rigid backing member 1810 as an individual piece is rotatable about a modified radial strut 1830 but in a plane at right angles to the pinch plane 1822 or substantially at right angles to the pinch plane. This is shown in a partially exploded view in Figure 46. The modified radial strut 1830 has a cylindrical end 1831 which may act as a bearing about which the rigid backing member 1810 as an individual piece may rotate. The rigid backing member 1810 as an individual piece may be held in the pinch position above the pinch slot 1809 by a torsional spring 1832, for example, fitted about the cylindrical end 1831 and in elastic contact with the rigid backing member 1810 as an individual piece. At its other end the rigid backing member 1810 as an individual piece has a mating surface or other means of attachment with the other modified radial strut 1833. The torsional spring 1832 may be extended for loading and unloading the movable member 1812 or a ruptured particular flexible tube 1806.
In another embodiment indicating how the movable member 1812 and springs 1824 may be loaded into the rotary pinch valve 1801, the stator 1803 may be consist of a number of laminations comprising consecutive laminar stator pinch disks with the cross section as shown in Figure 40 alternating with laminar stator spacer disks with a cross section as shown in Figure 41. These may be individually loaded over the rotor 1802 with a movable member 1812 and springs 1824 added for each laminar stator pinch disk until the whole stator 1803 is assembled about the rotor 1802.
In yet another embodiment, not shown in the
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Figures, the natural resiliency of a particular flexible tube 1806 may be enhanced by fitting over a particular flexible tube 1806 a short, essentially cylindrical, close fitting elastically deformable sleeve of a material preferably more resilient than the particular flexible tube 1806 itself. This short flexible sleeve would be fitted around the flexible tube in the vicinity of the pinch slot 1809 and preferably between the upstream and downstream aligners 1826. This close fitting sleeve may be held in axial position, over and above its frictional association with the particular flexible tube 1806, by physical interaction with a component of the stator 1803 such as the rigid backing member 1810 or movable member 1812, whether by small mating indentations or otherwise.
This embodiment acts as an alternative for providing the necessary spring action to ensure the full design movement of the movable member 1812. While slightly adding to the effective diameter of a particular flexible tube 1806, it avoids the need for the pair of springs 1824 and their associated loading into the stator 1803.
In another embodiment more than one pinch valve is located along the axial alignment of an alignment hole 1814. For example it is possible to have two pinch slots in axial alignment along an alignment hole 1814 and thereby create a three way valve with the common junction between the two pinch slots. This also may serve to reduce the overall size of the rotary pinch valve 1801 for a given number of valves. Figure 36 shows an individual rigid backing member 1810 for a particular pinch slot 1809. The rigid backing member 1810 is attached to the stator 1803 by radial struts 1811. However in another embodiment a single backing member is used for all the flexible tubes on one side of the rotary pinch valve 1801. Such a backing member may be a full piece of curved but rigid sheet material, for example, which can be either slid axially or rotated
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into place using the stator 1803 alone or together with the end plate 1813 for anchoring. In such an instance the flexible tubing which transverses the stator 1803, as is visible from the outside the rotary pinch valve 1801 as shown in Figure 36, would not be able to be seen. The said one piece of curved but rigid sheet material would then comprise the totality of backing members on that side of the rotary pinch valve.
In yet another embodiment the curved but rigid piece of sheet material is not a full continuous piece but yet still one piece such that material suitable for a rigid backing member is located strategically above the pinch slot 1809. In this case a portion of the flexible tubes which transverse the stator 1803 would be visible from the outside of the rotary pinch valve 1801.
In another embodiment the rotary pinch valve 1801 may be made programmable by incorporating a mechanism which allows any one cam disk 1820 to be rotatable to another fixed position relative to all other cam disks in the rotor 1802. This may be achieved for example by having bolt holes 1828 in the cam disks 1820 and cam spacer disks 1823 of the rotor 1802 at regular angular intervals as shown in Figure 47 for a cam disk 1820 only. In this embodiment the rotor 1802 would be comprised of various cam disks 1820 and cam spacer disks 1823 held together by bolts (not shown) . Any particular cam disk 1820 may be removed from the bolts and rotated to another angular position and then replaced on the bolts and assembled into a rotor 1802. Alternatively the cam disks 1820 and cam spacer disks 1823 may be held together by accommodating male and female fittings possibly also in association with a bolt(s). For example the cam spacer disks 1823 of the rotor 1802 may have male pin like protrusions which slide into female accommodations on the cam disks 1820 of the rotor 1802. These male and female fittings would be on a similar angular basis as the bolt holes thereby allowing the rotor 1802 to be disassembled and cam disks 1820
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rotated to appropriate positions whereafter the disks are reassembled into the essentially cylindrical whole rotor 1802 and placed in the stator 1803.
While the embodiment shown in Figure 36 has flexible tubes of equal diameter, in another embodiment the rotary pinch valve has flexible tubes of varying diameter.
In a further embodiment, a single stator pinch disk may be sufficient for a plurality of flexible tubes where the plurality of flexible tubes are of equal diameter and have an identical on/off duration for a cycle but at different times of the cycle. This is because the fixed cam profile of the associated single cam disk may deliver the same on/off program to each flexible tube but with a time delay.
In this embodiment, a single stator pinch disk may have a plurality of pinch slots and associated movable members and rigid backing members suitable for the plurality of flexible tubes rather than a single pinch slot 9 for a single particular flexible tube 6 as was the case for the previous embodiments.
In this embodiment also the stator may comprise a single stator pinch disk so as to house a plurality of flexible tubes and the rotor may comprise a single cam disk.
In the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, ie. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.
It is to be clearly understood that although prior art publication (s) are referred to herein, this reference does not constitute an admission that any of these documents forms part of the common general knowledge
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in the art in Australia or in any other country.
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