TECHNICAL FIELD

[0001] This invention relates to reciprocating pumps, and especially, though not exclusively to a low-head, water-powered reciprocating pumps which can be used to pump liquid, such as water, at higher pressure than the pressure of the liquid used for driving the pump.

[0002] By low -head, it is meant that the liquid falls only a relatively short distance from the supply level to the operating level of the pump. The relatively short distance can be from a few metres to as little as a few centimetres.

BACKGROUND ART

[0003] A low-head, water-powered reciprocating pumps which can be used to pump liquid, such as water, at higher pressure than the pressure of the liquid used for driving the pump was disclosed in Australian Patent No. 668619.

[0004] The pump disclosed in that document comprises a hollow housing having an inlet and an outlet between which a liquid passes, a primary chamber into which the liquid enters as it passes from said inlet to said outlet; a movable wall partly defining said chamber and movable from a first position to a second position in which the volume of the chamber is larger than when said wall is in said first position; valve means to open and close said outlet so that, when opened, liquid accelerates from said inlet to said outlet, and, when closed, liquid decelerates, firstly producing an increase in pressure in the housing so as to move said wall from its first position to its second position and then relaxing so as to produce a decrease in pressure; and return means to return the wall from the second position to the first position when the pressure has decreased, so that said wall is caused to reciprocate.

[0005] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

SUMMARY OF INVENTION

The present invention is directed to a low-head, water-powered reciprocating pump, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice. [0006] With the foregoing in view, the present invention in one form, resides broadly in a low-head, water-powered reciprocating pump comprising: a) a hollow housing having an inlet and an outlet between which a liquid passes, b) a primary chamber into which the liquid enters as it passes from said inlet to said outlet; c) a movable wall partly defining said chamber and movable from a first position to a

second position in which the volume of the chamber is larger than when said wall is in said first position;

d) valve means to open and close said outlet so that, when opened, liquid accelerates from said inlet to said outlet, and, when closed, liquid decelerates, firstly producing an increase in pressure in the housing so as to move said wall from its first position to its second position and then relaxing so as to produce a decrease in pressure; and

e) return means to return the wall from the second position to the first position when the pressure has decreased, so that said wall is caused to reciprocate.

[0007] In a preferred embodiment, the valve means opens the outlet when the pressure of the liquid in the housing falls below a predetermined level.

[0008] The valve means preferably comprises a flap which opens and closes said outlet and biasing means acting to open the flap, the biasing force of the biasing means being sufficient to open the flap against the decreased pressure of the liquid in the housing, but insufficient to prevent closing of the flap when the force provided by the liquid accelerating from the inlet to the outlet rises above a particular level.

[0009] In one alternative embodiment, the valve means could be a timer-activated valve and be automatically opened and closed according to a predetermined timing pattern.

[0010] Preferably, said return means comprises means for biasing the wall towards the first position. The biasing force of the means for biasing the wall is preferably sufficient to overcome the decreased pressure of the liquid in the chamber so that said wall moves back to the first position, but is insufficient to prevent said wall being moved towards the second position by the increased pressure of the liquid in the chamber.

[0011] In a preferred embodiment, the housing at least partly defines and encloses said chamber.

[0012] In an alternative embodiment, the chamber is in fluid connection with the housing between said inlet and said outlet. [0013] In one embodiment, the wall comprises a diaphragm. Preferably a piston is coupled to the diaphragm to provide the reciprocating motion for coupling to an attachment to the pump. Alternatively, the wall could itself form part of a piston arrangement, a bellows arrangement or a concertina arrangement, with a piston being coupled thereto.

[0014] The piston could be directly coupled to the wall, or could be coupled thereto via return springs, which absorb energy from the movement of the wall towards the second position and transfer the energy to the piston when the wall moves towards the first position.

[0015] In an embodiment, the housing at least partly defines a second chamber provided with an inlet and an outlet and the wall at least partly defines the second chamber, the outlet of the second chamber being openable and closable out of phase with that of the first-mentioned chamber so that the wall is moved from the first position to the second position by the liquid in the first chamber decelerating and providing an increased pressure on one side of the wall and is moved from the second position to the first position by liquid in the second chamber decelerating and producing an increased pressure on the other side of the wall when there is decreased pressure on the one side of the wall.

[0016] In one preferred embodiment, the wall is coupled to a reciprocating piston movable within a cylinder of a fluid pump arrangement to pump fluid, the cylinder being connected to a pumped fluid inlet via a first one-way valve and to a pumped fluid outlet via a second one-way valve.

[0017] Movement of the wall, and hence of the piston, from the second position to the first position thus causes flow of the pumped fluid from the pumped fluid inlet through the first oneway valve into the cylinder, and movement of the wall, and hence the piston, from the first position to the second position causes flow of the pumped fluid through the second one-way valve and through the pumped fluid outlet.

[0018] In one embodiment, the pump arrangement is used to pump water. In an alternative embodiment, the pump arrangement is connected to supply fluid to a turbine to produce electricity.

[0019] In one preferred embodiment, a pressure vessel having a compressible element therein is connected between the second one-way valve and the pumped fluid outlet to smooth the flow of pumped fluid through the pumped fluid outlet. The compressible element can be a bag having compressible fluid therein, or could be a solid compressible element. The compressible element is compressed by the pumped fluid flowing through the second one-way valve and expels the pumped fluid when no fluid is flowing through the second one-way valve, thereby smoothing the flow of the pumped fluid through the outlet.

[0020] In a further preferred embodiment, the valve means is controlled by a flood deactivating mechanism to prevent closure of the outlet during flood conditions. The flood deactivating mechanism preferably comprises a float switch coupled to rotate a pivoting arm into engagement with the valve means to prevent closure of the outlet.

[0021] In a preferred embodiment, the input to the pump may be located substantially adjacent to the output to the pump. It is preferred that the input may have an elongate tube or conduit associated therewith in order to space the source of the input fluid from the output. This will preferably provide cleaner, less disturbed fluid to the input which will normally assist with priming. The output flow may be agitated or aerated or turbulent which may cause issues with the input flow.

[0022] In a preferred embodiment, the elongate tube or conduit may extend to adjacent the drive tube or alternatively may have an inlet thereto which is located partially within the housing of the pump of the present invention or in the drive tube. The inlet to the elongate tube or conduit is preferably associated with a strainer or similar device to prevent detritus from entering the elongate tube or conduit.

[0023] Normally the pump of the present invention will require adjustment in order to function correctly or at optimum levels if the drive fluid input drops such as may occur in drought or low flow conditions. This can be overcome by providing an automatic throttling system for the pump.

[0024] In one preferred embodiment, the throttling system operates by changing the position of the exhaust fluid valve in the pump. In the preferred embodiment, a float or similar is provided in association with the exhaust fluid valve such that a drop in drive fluid level will cause the exhaust fluid valve to close at least partially. The float is preferably mounted to an arm which is in turn attached to an upstanding arm such that movement of the arm to which the float is mounted will rotate an upper portion of the upstanding arm. A cable or similar is preferably attached to an upper portion of the upstanding arm and to the exhaust valve.

[0025] In a preferred embodiment, a sniffer valve may be provided to allow a minimal amount of air to be drawn into the delivery pipe to cushion the pumping action. In the most preferred embodiment, a connector is attached to a nonreturn valve. The connector preferably mounts a short length of conduit with a plug in one end and a micro-irrigation tap located along the length of thereof. This assembly is normally attached to one of the straight through arms of a T piece which in turn is attached to the delivery outlet of the pump via a short conduit attached to the downcomer of the T piece. The delivery pipe is preferably attached to the other of the straight through arms of the T piece with a nonreturn valve provided between the T piece and the delivery pipe.

[0026] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

[0027] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

BRIEF DESCRIPTION OF DRAWINGS

[0028] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[0029] Figure 1 is a schematic cross- sectional view of a first embodiment of a pump according to the invention in a first phase of its operation;

[0030] Figure 2 is a view of the pump of Figure 1 showing the pump in a second phase of its operation;

[0031] Figure 3 is a view of the pump of Figures 1 and 2 in a third phase of its operation;

[0032] Figure 4 is an isometric view from the front of a pump according to a particularly preferred embodiment of the present invention.

[0033] Figure 5 is an isometric view from the rear of the pump illustrated in Figure 4.

[0034] Figure 6 is a schematic view of a pulse smoothing configuration which may be used according to a preferred embodiment of the present invention.

[0035] Figure 7 is a schematic cross section of the rear of the pump illustrated in Figure 5 showing the controls thereon. [0036] Figure 8A is a schematic side view of a pump according to a preferred embodiment in position with an input feed according to one preferred embodiment.

[0037] Figure 8B is a schematic side view of a pump according to a preferred embodiment in position with an input feed according to a second preferred embodiment.

[0038] Figure 8C is a schematic side view of a pump according to a preferred embodiment in position with an input feed according to a third preferred embodiment.

[0039] Figure 8D is a schematic side view of a pump according to a preferred embodiment in position with an input feed according to a fourth preferred embodiment.

[0040] Figure 9 is a cross-sectional schematic view of an alternative configuration to the pulse smoothing configuration illustrated in Figure 6.

[0041] Figure 10 is a schematic side elevation view of an automated throttle system according to a preferred embodiment of the present invention.

[0042] Figures 11A to 1 IE show various configurations of the use of an air chamber with the delivery conduit according to preferred embodiments of the present invention.

DESCRIPTION OF EMBODIMENTS

[0043] As shown in Figures 1 to 3 of the drawings, a first embodiment of a pump 1 according to the invention includes a housing 2 having an inlet 3 and an outlet 4. The inlet 3 is coupled to one or more pipes 5, which direct water from a source, such as a river, into the inlet 3 of the housing 2. The source of the water should be above the level of the inlet 3 so that the water enters the inlet under the action of gravity.

[0044] The height of the source above the inlet can be anything from a few centimetres to a few metres.

[0045] Within the housing 2 there is mounted a diaphragm 6, which can move within the housing 2 and which partly defines a chamber 7 in the housing between the diaphragm 6 and the side of housing 2 having the inlet 3 and the outlet 4 so that water entering through the inlet 3 flows through the chamber 7 and out through outlet 4. The diaphragm 6 is mounted on flexible rubber mounts 8, which enable the diaphragm to move between a first position, as shown in Figure 1, where the volume of the chamber 7 so defined, is relatively small, and a second position, shown in Figures 2 and 3, where the volume of the chamber 7 is relatively large. [0046] A tension spring 10 is attached between the diaphragm 6 and a threaded shaft 11 passing through the housing 2 so that, when the diaphragm is forced to its second position, the spring 10 is put under tension and acts to return the diaphragm to its first position. A wing nut 12 is threaded on the shaft 11 outside the housing and can be used t adjust the tension in the spring 10.

[0047] Also attached to the diaphragm 6, via a shaft 13, is a piston 14, which moves within a cylinder 15 when the diaphragm moves between its first and second positions.

[0048] The outlet 4 is closable by a flap valve 16 including a flap element 17 which can cover the outlet 4 to close it and which is attaches to a resilient element 18 attached to the housing 2. The resilient element 18 is biased by a compression spring 19 to bias the flap element 17 to the open position. The compression of the compression spring 19 is adjustable by means of a wing nut 20.

[0049] The operation of the pump 1 in order to reciprocate piston 14 in cylinder 15 will now be described.

[0050] Starting in the position shown in Figure 1, the diaphragm 6 is in the first position such that the chamber 7 is of relatively small volume and the flap valve 16 is held open by the bias of compression spring 19.

[0051] As water from the source flows through pipe 5 and inlet 3 into the chamber 7, as indicated by arrow 21, and out through outlet 4, it accelerates, building up momentum and force until the flap element 17 is closed against the action of compression spring 19. Water can therefore not flow out through the outlet 4. As the water in the chamber 7 is thus decelerated, it increases the pressure in the chamber 7 which acts against a side 9 of the diaphragm 6 to force diaphragm 6 to move to its second position against the bias of tension spring 10. This, of course increases the volume of chamber 7.

[0052] However, after a relatively short period of time, the water in the chamber relaxes and the pressure decreases until the pressure acting against the diaphragm 6, shown by arrows 22, and against flap element 17, becomes less than the biasing force of tension spring 10 and compression spring 19. Accordingly, as shown in Figure 3, the flap valve 16 will open allowing water to flow out through outlet 4, as shown by arrow 23, and the diaphragm 6 will be returned to its first position by the bias of tension spring 10. Water will then once again flow through pipe 5, inlet 3, as illustrated by arrow 24, and accelerate through chamber 6 and outlet 4, and the cycle will repeat. [0053] Thus, the piston 14, attached to diaphragm 6 will reciprocate in cylinder 15 as diaphragm 6 moves between its first and second positions.

[0054] In this embodiment, the piston 14 and cylinder 15 arrangement is used to pump water to a higher level than that of the source. It will however be appreciated that the action of the reciprocating piston can be utilised to power any desired attachment. In this embodiment, the cylinder 15 is in fluid communication with a pipe 25 extending between an

[0055] Inlet 26 positioned in a source of liquid to be pumped at a lower level and an outlet 27 for the pumped liquid. Conveniently, the liquid to be pumped is water from the same body of water as the water flowing from outlet 4 of the pump 1 enters. A filter 28 is positioned around the inlet 26 in the source of water to be pumped.

[0056] Between the cylinder 15 and the inlet 26, in the pipe 25, there is positioned a oneway valve 29 arranged to allow liquid flow only in the direction from the inlet 26 towards the cylinder 15. Between the cylinder 15 and the outlet 27, in the pipe 25, there is positioned a oneway valve 30 arranged to allow liquid flow only in the direction from the cylinder 15 towards the outlet 27. The one-way valves 29 and 30 conveniently comprise plugs 31, which sit on a constriction in pipe 25 and which are biased by the action of springs 32 towards the constriction so as to close the pipe 25 to liquid flow.

[0057] When the piston 14 is in its outward position, as shown in Figure 3, and is then moved back towards an inner position, it sucks liquid up through inlet 26 and one-way valve 29, as shown by arrow 33, into cylinder 15, until the position shown in Figure 1 is reached. In the next half of the cycle, where the piston is moved outwardly again, liquid is pumped out through one-way valve and outlet 27, as shown by arrow 34. Thus, a pulsing form of pump action takes place.

[0058] As illustrated in Figure 4, the pump is provided with a three part housing including a main body 41, a cylinder support portion 42 and a cylinder head 43. In this configuration, the diaphragm 6 has a central plate 44, normally of metal over which a rubber diaphragm member 45 extends. The main body 41 of the housing is provided with a pair of anchoring eyes 40 to allow the pump to be secured in position, potentially in a moving water flow. The cylinder head also has a priming plug 53.

[0059] A rear view of the pump is illustrated in Figure 5. In this Figure, the controls for the pump are illustrated. In particular, a main spring adjustment 46 is provided which allows the force applied by the main spring to be adjusted. Also illustrated is an autostart adjustment 47, a throttle 48 (on/off and high/low) and an exhaust valve handle 49. The operation of the controls will be explained below with reference to Figure 7.

[0060] In order to smooth the pulsing form of pump action, and improve the efficiency of the pump, a configuration such as that shown schematically in Figure 6 may be provided. In this configuration, a pressure vessel 35 is provided in liquid communication with the pipe 25 after the one-way valve 30. The pressure vessel 35 contains therein a cushion 36 which can contract and expand as pressure is applied thereto and released. The cushion 36 may be a physical cushion comprising a bladder filled with air or foam rubber, or alternatively a compressible volume or air for example can be provided. The cushion 36 has an outlet valve 37 extending through a wall of the pressure vessel 35 so that the pressure in the cushion can be adjusted.

[0061] Thus, as liquid is pumped from the inlet 26, via cylinder 15, through one-way valve 30 in a pulsing cycle, as indicated by arrows 38, when the liquid is under pressure from the pumping action, it enters the pressure vessel 35 and depresses the cushion 36, which contracts, as shown by dotted line 39. When the pressure is released by the pumping action, the cushion expands and forces the liquid from the pressure vessel 35 towards the outlet 27. The pulses of liquid from the outlet as therefore not so sudden and the pressures in the pipe 25 are reduced. This can protect a discharge pipe if it is already close to its maximum pressure rating.

[0062] To the control of the pump illustrated in Figure 5 and the cross sectional view of those controls illustrated in Figure 7, before installing the pump, a user will typically hold the exhaust valve handle 49 and "feel" what the valve is doing while undertaking the following steps. The user will first screw the autostart adjustment 47 out. This will typically stop the rubber discs 50 from holding the exhaust valve 17 open. The user will then typically screw the throttle control 48 inwardly so that the exhaust valve 17 is held open. The throttle stop 52 will limit how far the exhaust valve 17 can open. The user can then pull on the exhaust valve handle 49 in order to feel the way that the exhaust valve 17 closes. In this configuration, only the soft spring 51 is acting and the valve 17 will open and close with little resistance.

[0063] The user can then screw the throttle valve in and out in order to notice the change in the opening position of the valve 17. The user can then start winding the autostart adjustment 47 in war opening and shutting the valve to notice the resistance when the valve 17 is shut.

Normally, the main spring control 46 is left in an approximately mid position. The position of the main spring control 46 generally only changes with very low static head conditions in which the main spring control is screwed out 46 and very high static head conditions or short drive pipe ratios where the main spring control adjustment 46 is typically screwed in. [0064] Before starting the pump, the pump must be primed by removing the priming plug 53, filling the housing with water until it overflows from the prying plug opening and then replacing the priming plate 53. The user will then ensure that the main spring adjustment 46 is in the mid position. At this stage, one-way valve is normally installed in the delivery pipe.

[0065] An adjustment procedure is then undertaken for the first time start-up. In this, the exhaust valve 17 is held closed using the handle 49 for approximately 15 seconds so that any excess air can bubble out of the drive pipe 5. The user then pushes the exhaust valve 17 open using the handle 49. The force of fluid against the exhaust of 17 will then typically drive the exhaust valve 17 closed and the user should then pushes open again. The user should repeat this action typically a number of times in order to get a feel for the valve action. Doing so rhythmically will typically assist with starting the pump. Whilst operating the valve 17 with the exhaust valve handle 49 with one hand, the user should then screw the autostart adjustment 47 in until the valve 17 begins to open and close automatically. For high drop sites, the user can screw the autostart adjustment 47 in a little in order to lessen the force required to push the valve 17 open. The user may also need to adjust the throttle 48 somewhat in order to achieve a relatively fast cycling action of opening and closing of the valve 17 of about 0.5 seconds per cycle. The user can then adjust the autostart adjustment 47 so that after the user pulls on the handle 49 to stop the pump, it takes a small force to start the pump going again. For low drop sites, the pump can start automatically.

[0066] At this stage, the pump will normally be operating on low throttle meaning relatively quick, low energy rams. Once the delivery pipe five has filled, the diaphragm six will generally begin pumping against the full delivery had pressure and the user will typically need to adjust the throttle 48 for maximum output. To do this, the user will typically screw the throttle 48 in until the longest exit/is visible from the outlet and then screw the throttle 48 out until the user sees the/beginning to get shorter. This will typically be near the maximum output at which point, the user can tighten the control lock nuts on the main adjustment spring 46, the throttle 48 and the autostart adjustment 47. One final check is to hold the valve 17 in different positions using the exhaust valve handle 49 to see a sure action for the pump to resume operation.

[0067] Illustrated in Figure 8 A to 8D is a series of alternate input feeds. The configuration illustrated in Figure 8A has a strainer 60 located on the inlet side of a weir 62 and connected to an elongate tube 80 which extends to the inlet side of the pump. The strainer 60 is located below the water level 61 on the inlet side of the weir. Alternatively as illustrated in Figure 8C, and internal strainer may be located within the chamber 7 and connected to the inlet side of the pump. As illustrated in Figure 8D, the strainer can be located in the drive pipe 5. In all embodiments, the benefits of providing a strainer provides cleaner, less disturbed input water and helps starting up and priming as opposed to having the strainer 60 directly associated with the inlet side of the pump such as is illustrated on Figure 8B.

[0068] Illustrated in Figure 9, is an air sniffer valve that can be used as an alternative to an air chamber to smooth the pulsing form of pump action. The purpose of the sniffer valve is to allow the pump to draw in a very small amount of their which is forced into the delivery pipe and accumulates, typically due to gravity, in either a chamber or in downhill sections of the delivery pipe. Therefore, the sniffer valve may be used with an air chamber 200 provided in or in association with the delivery pipe 210 in order to allow space for air to accumulate and act as a cushion for the pulsing form of pump action. Normally, the air chamber 200 will be positioned in such a manner that the air chamber 200 can fold in flood conditions. Various configurations are illustrated in Figures 11 A to 1 IE.

[0069] If the delivery pipe has any significant rises and drops, say greater than 10% of the overall pumping height, then the sniffer valve system may be appropriate and an air chamber with an internal membrane that can be provided with pressurised air can be used. An automatic air purging valve located at any high point is also an option which allows the sniffer valve system to operate.

[0070] In the preferred embodiment of the sniffer valve illustrated in Figure 9, a connector 91 is attached to a nonreturn valve 92. The connector 91 mounts a short length of conduit 93 with a plug 94 in one end and a micro -irrigation tap 95 located along the length of thereof. This assembly is normally attached to one of the straight through arms of a T piece 96 which in turn is attached to the delivery outlet 97 of the pump via a short conduit 101 attached to the downcomer of the T piece 96. The delivery pipe 98 is attached to the other of the straight through arms of the T piece 96 with a nonreturn valve 99 provided between the T piece 96 and the delivery pipe 98. This configuration also shows a strainer 100 attached to the inlet to the pump.

[0071] In use, the micro-irrigation tap 95 is adjusted so that only a minimal amount of air is drawn in through the sniffer valve.

[0072] Illustrated in Figure 10, is a preferred embodiment of the automatic throttling system for the pump. Normally, the pump will stop and require adjustment if the input drops for example due to drought or low water levels. The provision of an automatic control or throttling system such as that illustrated in Figure 10 will typically allow the pump to operate continuously and therefore save loss of output as well as save labour in adjustment. As illustrated in Figure 10, a weighted float 65 is attached via a pivot 66 to an upstanding arm 67 attached via a cable 68 to the exhaust valve handle 49. As the water level drops, the weighted float 65 drops with it which means the upstanding arm 67 is pulled rearwardly, tensioning the cable 68 which pulls the exhaust valve handle 49 closed. As the water level rises, the reverse occurs.

[0073] Other variations, modifications and improvements will be apparent to a person skilled in the art without departing from the scope of the present invention. For example, the valve closing the outlet 4 could be timer activated to open and close in a predetermined cycle. A second chamber, inlet and outlet with valve could be provided in the housing on the other side of the diaphragm from the first chamber and arranged so that water pressure moves the diaphragm in both directions. The diaphragm could be arranged to activate a double acting piston pump or large return springs could be used to absorb energy from the diaphragm movement and then push the pump piston while the diaphragm is returning to its first position. Furthermore, the pump could be designed so that a low pressure effect causes the diaphragm to return to the first position. Where a substantial water supply is available, for example about 50 litres/second from a height of 1.2 metres, a large version of the pump could be used to power a turbine and produce electricity.

[0074] In the present specification and claims (if any), the word 'comprising' and its derivatives including 'comprises' and 'comprise' include each of the stated integers but does not exclude the inclusion of one or more further integers.

[0075] Reference throughout this specification to 'one embodiment' or 'an embodiment' means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases 'in one embodiment' or 'in an embodiment' in various places throughout this specification are not necessarily all referring to the same embodiment.

Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.