Field of the Invention

The present invention relates to valves and more particularly, though not exclusively, to valves suitable for use in domestic boiler water circuits.

Background to the Invention

In new domestic water heating applications, the use of combination boilers is becoming more prevalent. These boilers heat water for both the drinking water tap (eg washing, drinking and cleaning) and radiator (heating) water circuits. These boilers are often referred to as "combi-boilers" .

When installing a combi-boiler or carrying out maintenance on a radiator circuit, once the installation or maintenance has been carried out, water is pumped into the heating circuit from a domestic cold water supply. Once the heating circuit has an adequate water supply, when in use, the remaining water supplied by the water inlet is provided to the tap circuit. This system has the disadvantage that under certain conditions water from the radiator circuit can leak or syphon back into the tap circuit causing contamination. Non-return and double check valves are recommended to be included in filling loops, but these are not to be relied upon. It is therefore recommended that the supply to the radiator circuit be disconnected from the water supply inlet after installation or the completion of maintenance before commencing use of the boiler. Complete disconnection of the filling loop after use is essential and is, in fact, a UK water authority bye-law. However, in practice, it is

found that in many cases the radiator circuit is left connected and so the leakage or syphon effect can occur. Disconnection does not occur through ignorance of both the user and the installer in that they do not perceive the need to disconnect the line.

Contamination of the tap circuit by water from the radiator circuit can result in discolouration or perhaps the spread of diseases.

It is an object of the present invention to obviate or overcome at least one disadvantage of the prior art whether or not referred to herein.

Summary of the Invention

According to the present invention, there is provided a valve comprising an inlet and an outlet and a path of fluid communication between the inlet and outlet, means for selectively allowing fluid to flow along the path of fluid communication and means for preventing fluid from flowing along the path of fluid communication, and an opening from the valve to atmosphere, whereby when fluid is prevented from flowing along the path of fluid communication an atmosphere gap is created between the inlet and the outlet and when fluid is prevented from flowing along the path of fluid communication neither the inlet nor the outlet is in fluid communication with the opening to atmosphere.

In this specification, the term "atmosphere" means the ambient atmosphere around the valve.

By creating in a "closed" configuration (no fluid flow) of the valve an atmosphere gap between the inlet and the outlet, they are effectively disconnected.

Suitably, the valve is adapted such that the gap between the inlet and outlet drains substantially completely of liquid in at least one orientation with the valve in its closed configuration.

Suitably, the valve is biased towards the position in which fluid is prevented from flowing along the path of fluid communication between the inlet and the outlet.

Suitably, the valve comprises a piston through which water flows from the inlet towards the outlet. Preferably, the piston moves to generate the atmosphere gap.

The means for selectively allowing fluid to flow may comprise a piston in a tube, the piston comprising the path of fluid communication between the inlet and the outlet, the piston comprising an entry port and an exit port in fluid communication with the inlet and outlet only in an "open" configuration and an opening in the piston which in a "closed" configuration is open to atmosphere.

Suitably, the piston is biassed towards its "closed" configuration in which fluid is prevented from flowing.

Suitably, a non-return valve is provided between the inlet and the outlet. Suitably, means are provided for biassing the non-return valve to is closed position. Suitably, the non-return valve is located in the piston.

Suitably, the means for selectively allowing fluid to flow comprises a sealing means biassed towards a sealing

position, which sealing means can be moved to a position in which fluid can flow. Conveniently, movement of the sealing means to the position in which fluid can flow is caused by movement of the piston.

Suitably, there is a second sealing means on the other side of the atmosphere gap. Conveniently, the second sealing means is biassed towards a position in which fluid cannot flow.

Normally, the fluid will be a liquid, usually water.

Suitably, the movement of the valve between the fluid flow and the fluid flow prevention positions can be manually controlled.

Suitably, a fail-safe mechanism is provided to prevent movement of the piston when the inlet is not under pressure.

Conveniently, the fail-safe mechanism comprises a one-way valve coupled to an insert within a shaped slot.

Suitably, the valve is suitable for use with a pressurised water system. Suitably, the system is a heating system.

Suitably, means are provided for moving the valve between its open and closed configurations and control means for operating the moving means.

Suitably, their is also provided a solenoid, a motor or a main pressure pilot system, operable to operate the valve.

According to another aspect of the present invention, there is also provided a valve suitable for use with a

combination boiler according to any one or more of the preceding paragraphs.

In a further aspect, the invention includes a combination boiler incorporating a valve according to the preceding paragraph.

According to yet another aspect of the present invention, there is provided a boiler comprising means to supply water to a water circuit and a pressure monitor, whereby when the pressure in the water circuit falls below a predetermined amount, water is supplied to the water circuit.

Suitably, the boiler is a domestic boiler.

Preferably the water circuit is a heating circuit.

Suitably, the means to supply water comprises a valve according to any preceding paragraph.

The valve according to and as part of the present invention is significantly easier to operate than prior apparatus for use with filling loops and, in particular does not require a skilled operator.

Brief Description of the Drawings

The present invention will now be described, by way of example only, with reference to the drawings that follow; in which:

Figure 1 is a schematic water circuit diagram including a valve according to the present invention.

Figure 2 is a schematic illustration of a valve in accordance with the present invention.

Figure 3 is an enlarged partly sectional illustration of part of the valve shown in Figure 2 in a "closed" configuration.

Figure 4 is a view of the valve shown in Figure 3 in an "open" configura ion.

Figure 5 is an enlarged sectional view of a valve of a second embodiment of the present invention in an "open" configuration.

Figure 6 is a view of the valve shown in Figure 5 in a "closed" configura ion.

Figure 7 is an enlarged schematic sectional view of an arrangement that can be used in conjunction with the present invention.

Figure 8 is an enlarged schematic illustration of the slot shown in Figure 7.

Figure 9 is a cross-sectional illustration of a third embodiment of the present invention in its "closed" configuration.

Figure 10 is an end elevation of the valve shown in Figure 9.

Figure 11 is a plan view of the piston body of the valve shown in Figures 9 and 10.

Figure 12 is a cross-sectional illustration of the third embodiment of the present invention in its "open" configuration.

Figure 13 is a schematic perspective illustration of a fourth embodiment of the present invention.

Figure 14 is a cross-sectional illustration of the fourth embodiment of the present invention in a "closed" configuration.

Figure 15 is a cross-sectional end elevation of the valve shown in Figures 13 and 14.

Description of the Preferred Embodiments

Referring to Figure 1, there is shown a cold water source 1, typically at 90 pounds per square inch, coupled by a flexible hose 3 to an input line 5 to a boiler 7. The boiler will typically operate at 30 pounds per square inch. Between the source 1 and the input line 5 of the boiler 7 is a valve 6 in accordance with the present invention.

Referring to Figure 2, there is shown a water inlet 2 and a water outlet 4. Between the inlet 2 and outlet 4 is the valve 6. The valve 6 comprises an open-ended generally hollow cylindrical outer tube 8 having two cut away portions 9.

Referring to Figure 3, within the tube 8 there is shown a piston 10 over the inlet 2.

The first piston 10 comprises a generally cylindrical body 14 through which there is a bore 16 from an entry port 42

to a chamber 25. The piston 10 can slide within the tube 8, but is sealed against fluid flow by two O-rings 18. Between the body 14 and the tube 8 is an annular gap 19 bounded by the body 14, tube 8 and O-rings 18.

The body 14 of the piston 10 comprises a cylindrical first hollow portion 20 and a cylindrical second hollow portion 22 of reduced diameter relative to the first portion 20. The first portion 20 extends outwardly from the end of the tube 8 to form a button 24 (Figure 2) .

In the hollow chamber 25 within the reduced diameter second portion 22, there is provided a circular sealing washer 26 mounted on a cylindrical rod 28 on the longitudinal axis of the tube 8 such that there extends from one side of the washer 26 a spigot 30 through a hole

31 in the end 33 of the second portion 22. On the rod 28 is mounted a biasing spring 32 supported by a reaction plate 34 itself supported by internal flanges 36 extending inwardly from the reduced diameter portion 22. The spring

32 acts against a plate 37 supporting the washer 26 at the end distant from the reaction plate 34. Around the second portion 22 is an O-ring 39.

Between the first portion 20 and a lip 41 of the tube 8 is a compression spring 43.

Projecting through the tube 8 is a limiting bolt 38 which projects into a groove 40 in the piston 10.

In the "closed" configuration of the valve 6 shown in Figure 2, the bore 16 extends from its port 42 through the first portion 20 of the piston 10 to the hollow interior of the reduced diameter second portion 22 forming a path of fluid communication therebetween. However, in this

configuration water cannot pass beyond the second portion 22 because the washer 26 seals the only exit.

Adjacent to and spaced from the piston 10, on the other side of the cut away portions 9, is a second sealing washer 50 also mounted on a cylindrical rod 52 substantially on the longitudinal axis of the tube 8. On the rod 52 is a biasing spring 54 which acts against a plate 56 at the washer end of the rod 52 and against a reaction plate 58 at the other end. The rod 52 in this case ends at the surface of the washer 50.

The washer 50 can seal chamber 60 against sealing plate 62 in which there is a circular hole having a diameter greater than the diameter of the cylindrical rod 52. From the chamber 60, there is a bore 64 to the outlet 4.

The chamber 60 is formed in a block 66 within the tube 8, the block 66 having a cylindrical recessed portion 68 defined by shoulders 70.

It will be appreciated by those skilled in the art that the washer 26 can move against the bias of spring 32 within the chamber 25 in a direction substantially parallel to the longitudinal axis of the tube 8. Similarly, the washer 50 can move within its chamber 60 against spring 54 in the same direction.

In the "closed" configuration shown in Figure 3, water can flow from the inlet 2 through the bore 16 to the chamber 25. The reaction plate 34 has an internal diameter greater than the external diameter of the rod 28 allowing the water to flow into the chamber 25. Alternatively, the plate 34 can include a plurality of holes therethrough. Water cannot escape from the chamber 25 because the spring

32 biases the washer 26 against the end of the second portion 22. The sealing of the washer 26 is enhanced by the water pressure. Water can also flow around the annular gap 19, but cannot pass the O-rings 18.

Water may also lie in the valve 6 between the second sealing washer 50 and the outlet 4. However, again, the water cannot pass beyond the washer 50 because its spring 54 seals the chamber 60 against sealing plate 62. Thus, in the "closed" configuration shown in Figure 2 there is an atmosphere gap 70 between the water supplied from the inlet 2 and the water and fluid communication with the outlet 6. That is, since the atmosphere gap 70 is open to atmosphere via the cut away portions 9, there is a pressure sink between the two seals 26 and 50, avoiding any possibility of leakage or siphonage.

The valve 6 can be moved from its "closed" configuration shown in Figure 2 to its "open" configuration shown in Figure 3 by depression of the button 24.

As the piston 10 is push inwards by depression of the button 24, the end of the rod 28 in the atmosphere gap 70 approaches the rod 52. Before the two rods meet, the O- ring 39 seats itself within the recess portion 68 to form a seal between the shoulders 70 and the exterior of the second portion 22. Continuing depression of the button 24 causes the rods 28, 52 to touch. The biasing springs 32, 54 are so balanced that as the rods 28, 52 meet, both washers 26, 50 are forced away from their sealing engagements with end portion 22 and sealing plate 62 respectively. Travel of the piston 10 can be delimited by contact of the end of second portion 22 with the sealing plate 62 or by the action of bolt 38 in groove 40.

Referring now to Figure 4, the valve 6 is shown in its "open" configuration in which water can flow from the inlet through the valve 6 to the outlet 4. In this configuration, the piston 10 has been moved longitudinally towards the outlet 4 by depression of button 24.

The spigot 30 of the rod 28 which extends beyond the end of the second portion 22 abuts against the rod 52 supporting the second sealing washer 50. The springs 32, 54 are balanced such that as the rod 28 is driven towards the rod 52, the two washers 26, 50 are forced away from their sealing surfaces which, in the case of the washer 26 is the end of the second portion 22 and, in the case of the washer 50, is the sealing plate 62.

Thus, in the "open" configuration shown in Figure 4 water can flow from the inlet 2 through the bore 16 into the chamber 25, passed the washer 26 (which has been forced away from the end 33 of the second portion 22) . Since the recessed portion 68 has been sealed by O-ring 39, the water can only pass into the chamber 60 (to which access can now be gained as the washer 50 has been forced back away from plate 62 by the rod 28) . Water flows from the chamber 60 through bore 64 to the outlet 4. Accordingly, in the "open" configuration water can flow from the inlet 2 to the outlet 4.

Upon release of the button 24, the spring 43 acts to return the valve 6 to its "closed" configuration shown in Figure 3. The washers 26, 50 are biased back towards their sealed positions by springs 32, 54 respectively preventing water from flowing. Thus, since the gap 70 is open to atmosphere, an atmosphere gap is created between the water inlet and the water outlet. This means that it

is not necessary for the water supply to be disconnected in order for it to be safe.

It is noted that alternative designs within the knowledge of the person skilled in the art are possible. For instance, the entry port 42 can be replaced by a slot in the piston 10.

Referring now to Figures 5 and 6 of the drawings that follow, there is shown a second embodiment of the present invention.

In the second embodiment, there is shown a valve 100 comprising a cylindrical outer tube 102 in which there is located an opening 104 to atmosphere. Within the tube 102 is a hollow piston 106 (the interior of which is marked by dashed lines in Figures 5 and 6) . Access to the interior of the piston 106 can be gained through entry port 108 and exit port 110. The piston 106 includes an opening 112. On either side of the entry port 108 are O-rings 114. On either side of the opening 112 are O-rings 116. On either side of the exit port 110 are O-rings 118. Also provided is O-ring 120 intermediate the O-rings 114 and 116.

In the "open" configuration of Figure 5 water can flow from inlet 122 to outlet 124 via the piston 106 as explained below. Water enters into the inlet 122 and enters the interior of the piston 106 via entry port 108. The water flows through the interior of the piston 106 to egress through exit port 110 out through outlet 124. In this position, water is constrained to follow this route by the presence of O-rings 114 and 118. The O-rings 116 on either side of the opening 112 prevent water from flowing out of the opening 112.

When released from the "open" configuration of Figure 5, a biassing spring 126 and the end of the tube 102 forces the piston 106 towards its "closed" configuration shown in Figure 6.

In the "closed" configuration the entry port 108 and exit port 110 are misaligned from the inlet 122 and outlet 124 respectively. Therefore, water from the inlet 122 can enter the tube 102, but cannot pass the O-rings 114 and 120. Similarly, water from the outlet 124 cannot pass 0- rings 114.

The openings 104 (and the but 102) and 112 (and the piston 106) are, in this configuration, aligned allowing water between the inlet and the outlet to drain from the valve 100 thus creating an atmosphere gap between the inlet and the outlet as required.

In the travel of the piston 106 between its "open" and "closed" configurations (in both directions) the O-ring 120 prevents water passing from the inlet 122 through the opening 104. The piston 106 can be moved by button 128 projecting from the end of tube 108.

This second embodiment of the present invention has the advantage of simplicity and ease of manufacture.

The atmosphere gap provided by opening 104 can be connected to the pressure relief valve (not shown) in the boiler allowing the water to be expelled conveniently.

Referring now to Figure 7, there is shown a cold water inlet 150 within which there is a one way valve 152 having a stem 154 connected to a disc 156.

The cold water inlet 150 is coupled to a valve 158 of the type described to above in relation to the first and second embodiments of the present invention. However, in this case, piston 160 includes a slot 162 into which the disc 156 projects. The valve 152 is sprung biassed by a spring (not shown) towards its closed position.

Referring to Figure 8 of the drawings, the slot 162 in the piston 160 is shown in more detail. The slot comprises an outer layer having an elongate portion 164 connected to a circular portion 166 underneath which there is an elongate elliptical slot (shown by dashed lines 168) having a width substantially similar to that of the diameter of the circular portion 166.

When the water inlet 150 is under pressure, the one way valve 152 is opened forcing the disc 156 upwardly towards the piston 160 into the elongate elliptical part of the slot 162. In this position the piston can move freely as described above in relation to the first and second embodiments, the disc 156 moving along the elongate elliptical portion 168 of the slot 162, the stem 154 moving along the elongate portion 164.

When the cold water inlet 150 is not under pressure, the one way valve 152 closes lowering the disc 156 so that it lies substantially within the circular portion 166 of slot 162. In this position the piston 160 cannot be moved because the disc 156 is trapped within the circular portion 166 as shown in Figure 7.

Thus, the arrangement described in Figures 7 and 8 can be used to provide a fail safe mechanism for the operation of the valve 158 if the cold water supply is turned off or losses pressure. In these circumstances, the valve 158

cannot be operated. It will be appreciated that the arrangement described in relation to Figures 7 and 8 can be used in conjunction with either of the embodiments of the invention described above.

Referring to Figures 9 and 10, there is shown a third embodiment of the present invention in a closed configuration.

In Figure 9, there is a valve 202 suitable for coupling to a domestic cold water supply in-line with a combination boiler.

The valve 202 has a water inlet 204 and a water outlet 206. The valve 202 comprises an open-ended generally hollow cylindrical outer tube 208 from which depends a vent tube 210. In the tube 208, opposite the vent tube 210 is a cutaway vent slot 212 which extends around nearly half of the tube 208.

A piston 214 is slidable within the tube 208. The piston 214 comprises a generally cylindrical body 216 through which there is a generally L-shaped bore 218, one end of which, in the open configuration (see Figure 12) , lies over the inlet 204. The other end of bore 218 opens into an internal chamber 220 within which is mounted a non¬ return valve 222. Adjacent the chamber 220 is an annular circumferential groove 224, which groove 224 is in fluid communication with bore 218 by hole 225 (Figure 11) . Two circular outlets 226 are provided from chamber 220 to outlet 206.

Six O-rings 228-238 are provided in annular grooves along the exterior of the piston 214. O-rings 228 and 230 are located on either side of the opening of the bore 218. O-

rings 232 and 234 lie intermediate O-ring 230 and the annular groove 224. O-rings 236 and 238 are located on either side of the outlets 226.

At the end of the piston 214 distant from chamber 220 is a reduced diameter portion 240 forming offset shoulders 242, 244. The reduced diameter portion 240 includes a bore 246. A flange 248 projects from the reduced diameter portion 240 to form a shoulder 250 opposing shoulder 244.

Referring now additionally to Figure 11 of the drawings that follow, the internal chamber 220 has an enlarged diameter portion 252 forming an annular shoulder 254 for mounting and locating the non-return valve 222 as shown in Figure 10. The non-return valve 222 comprises a plug 256 seated by O-ring 258 in a plug receiving narrowing portion of chamber 220. A plunger 260 extends from the plug 256. The mounting member 262 for the non-return valve 222 is generally T-shaped in cross-section with a leg 264 comprising a hollow circular cylindrical tube extending to a circular (in end elevation) head 266 which engages in the enlarged diameter portion 252 of chamber 220. The plunger 260 extends into leg 264. The plunger 260 is biassed towards its closed configuration (shown in Figure 9) by helical spring 268.

From the other end of the piston 214 extends a rod 270 journaled in the piston 214. The rod 270 extends out of the tube 208 through a closure plate 271. A button 272 is attached to the end of the rod 270 projecting from tube 208 by means of a screw 274 and washer 276. A lock nut 278 lies between the closure plate 271 and button 272. Also between the closure plate 271 and button 272 is a helical spring 280 which biasses the button 272 away from

the tube 208. A screw 282 projects through the tube 208 adjacent the closure plate 271.

In this configuration, the button 272 is biassed outwardly by spring 280 towards its closed configuration, and its travel in that direction is limited by shoulder 244 abutting screw 282.

Referring now to Figure 12 of the drawings that follow, the valve 202 is shown in its open configuration, but with the non-return valve 222 still engaged.

The valve 202 is transferred from its closed configuration

(Figure 9) to is open configuration (Figure 12) by depressing the button 272 against the bias of spring 280.

In the open configuration water flows from the inlet 204 through the bore 218 to the non-return valve 222. With no water in the outlet end, for instance if a radiator heating system is to be filled, the non-return valve 222 is forced open against the bias of spring 268. Water then flows into chamber 220, through outlets 226 and to the outlet 206. This flow continues until the pressure on the outlet side of the non-return valve reaches a predetermined level. Typically, inlet pressure is about 3 bar while the desired system (ie outlet) pressure is about 1.5 bar. The back-pressure (outlet pressure) from the system acts on the outlet end of piston 214. Thus, the larger the cross-section presented by the outlet end of piston 214, the greater for force on the piston 214 pushing it outwards at a given back-pressure. By correctly sizing the outlet end of the piston 214 and the strength of the spring 280 acting on the button 272, the valve can be made to move to its closed configuratio (ie the button retracts) at an outlet pressure of about 1.5

bar. The non-return closes as the water pressure from the inlet is shut off as the valve moves to its closed configuration. The system, therefore, automatically shuts off the water supply when the heating system to be filled is full. The piston 214 end size and spring 280 strength can be varied to achieve different pressure cut-offs. (The second embodiment of the present invention, described above, can operate in a similar fashion) .

In the open configuration the junction between inlet 204 and bore 218 is sealed by O-rings 228 and 230. Water can flow into groove 224 through hole 225, but is sealed from further egress by O-rings 234 and 236.

As the piston 234 transfers to its closed configuration, or as the case may be is manually transferred, the bore 218 ceases to be aligned with inlet 204 stopping the flow of water therethrough. As the groove 224 becomes aligned with vent tube 210 and vent slot 212 water in the bore 21'8 can drain therethrough to ensure an air gap develops between the inlet 204 and outlet 206. Residual pressure in the water in the bore 218 can cause it to spray out from the vents 210, 212.

The button 272 can be screwed inwardly to tension the spring 280 thus allowing the pressure at which the valve 202 switches itself off to be adjusted.

Referring to figures 13-15 of the drawings that follow, a fourth embodiment of the present invention is shown in which a substantial 20mm air gap is obtained between the inlet and outlet.

The fourth embodiment is similar to the third so it will only be described briefly.

In the fourth embodiment there is a two part piston 302, 304 connected by an intermediate rod 306 about which there is a plastic ring 308. In the first piston part 302, two drain holes 310 are provided from the interior to the exterior of the piston part 302. An '0' -ring 312 fitted inside first outer body 314 prevents leakage from the holes 310 in the 'closed' configuration shown.

To open the valve, button 316 is depressed and holes 310 are forced across to the second outer body 318 after which the inlet 320 of first piston part 302 aligns with supply inlet 322 to transfer fluid across the air gap 324.

Also shown in Figure 13 is an optional drip tray 326.

It is noted that in at least one orientation, each embodiment of the present invention will drain liquid from the air gap between inlet and outlet.

For each embodiment of the present invention, a gauze filter may be provided on the inlet and outlet to protect, in particular the O-rings from contaminants.

The valve of the present invention may, in effect, be automated by providing a pressure sensor in the water boiler 7 coupled to the valve 6. When the water pressure in the boiler 7 falls below a predetermined setting the valve 6 can be opened to supply water until a desired pressure is achieved. The valve 6 can be activated by a solenoid instead of a button for automation.

The valves of the embodiments described herein can be used as a retro-fit accessory or be installed as a built-in component in a combi-boiler.

It will be appreciated that various features of the first to fourth embodiments may be combined and/or substituted.

In any embodiment, a non-return valve can be located prior to the valve described herein in the water system.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) , may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s) . The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.