AU2005201179A1 - Pump - Google Patents

Description

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AUSTRALIA

Patents Act 1990 COMPLETE

SPECIFICATION

STANDARD

PATENT

Applicant(s): IAN MACDOUGALL Invention Title:

PUMP

The following statement is a full description of this invention, including the best method of performing it known to me/us:

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AUSTRALIA

Patents Act 1990 COMPLETE

SPECIFICATION

STANDARD

PATENT

Applicant(s): IAN MACDOUGALL Invention Title:

PUMP

The following statement is a full description of this invention, including the best method of performing it known to me/us:

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2

PUMP

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Field of the Invention 00 The present invention relates to pumps and in ~The presentineto particular to pumps primarily suitable for use with windmills and will be described hereinafter with reference to this application. However, it will be appreciated that C-1 the invention is not limited to this particular field of use.

1q 0 Background of the Invention Windmills are used to pump underground water to the surface by wind power. Typically the pump is connected-to the windmill turbine via a crank, and in some cases a gear box, and an elongate drive shaft. This drive shaft usually takes the form of a long chain of jointed hollow high tensile steel rods, which, when the pump is in operation, reciprocate vertically inside a water delivery pipe. Typically, this water delivery pipe is manufactured from galvanised iron or heavy PVC pipe and has an internal diameter of between 38 and 50mm. The water delivery pipe is usually nested inside a bore casing of substantially larger diameter. The water delivery pipe at its lower end is submerged beneath the standing water level in the bore hole and has a foot valve at its lower end. The foot valve allows water to enter the pump from below but not to exit back into the well.

A problem with conventional windmill pump designs is that they must be located substantially vertically below the windmill due to the nature of the driving chain of metal rods. Another problem with the system comprising a chain of rods is that the crank must not apply any significant downwards force since the chain may simply c- buckle at its joints when under compression and then make tdamaging frictional contact with the internal wall of the water delivery pipe. This frictional contact could be 00 most damaging at high rotational speeds of the windmill turbine. This is a major problem inherent in a C conventional windmill design.

_Another problem with conventional windmill designs is c- the inertia that needs to be overcome for the windmill to begin rotating and thus become operational. This inertia N-I 10 is contributed to by the mass of water and the mass of the rods.

A further problem with conventional windmill designs is that if during the downstroke of the pump the driving rods make contact with the internal walls of the delivery pipe, frictional contact reduces the efficiency of the windmill.

One known windmill pump overcoming some of the problems of the prior art is that known as a Draw Plunger Pump. These pumps use a wider diameter delivery pipe, to enable the plunger to be pulled out of the pump and up to the surface for pump servicing without the need to pull pipe sections up at the same time. This makes owner/servicing possible but, the pipe is heavier and more expensive. By contrast, servicing of standard windmill pumps requires specialist equipment to haul up the entire assembly of rods and pipes, together with the water contained therein to the well head for disassembling stages. Worn pump seals can then be replaced and reassembly in stages may occur again using the specialist equipment.

Conventional windmill pumps are also limited in terms of the range of the possible gearing they can use. The only mechanical advantage obtainable in some windmills is

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-4that available by virtue of being able to alter the turbine radius/crank radius ratio. However, some manufacturers do place a gear box between the crank and reciprocating rod column allowing a certain but limited range of gearing.

In summary major disadvantages of most conventional windmill pumps are the cost and difficulty of servicing and replacement of pipes, rods and other components corroded by bore water and/or worn by friction.

Furthermore, the constraint imposed by the structure of the system requiring the windmill to be located vertically above the water source is a serious restriction.

Summary of the Invention According to a first aspect of the present invention there is provided a pump system having transmission means to receive reciprocating drive from a drive system, and a tubular system adapted to extend from the transmission means to a remote location below the water level in a water source, the tubular system providing a master piston arrangement which includes a master piston and a master cylinder providing a first chamber through which the master piston is adapted to be reciprocatedly driven by drive from the transmission means, a slave piston arrangement which includes a slave piston and a slave cylinder providing a second chamber through which the slave piston is adapted to be driven in a manner corresponding to movement of the master piston, a hydraulic connecting conduit interconnecting the first chamber and a second chamber so that ~n the master piston and slave piston move tcorrespondingly, 0(d) a pump adapted to be mounted at the remote location to be submersed in the water and driven by the slave piston to pump water through the tubular system, conduit means for ducting water pumped by the C pump to a discharge location, and S(f) valve means to cause water to be pumped up c 10 throughthe conduit means.

One specific application is to down-bore water pumps for windmill drive but embodiments extend to other applications such as surface pumping.

In one form, when the pump system is orientated for installation down a bore hole, there is defined a master superior region within the first chamber and above the master piston, a master inferior region within the first chamber and below the master piston, a slave superior region within the second chamber and above the slave piston, a slave inferior region within the second chamber and below the slave piston, and wherein the hydraulic connecting conduit connects the master superior region to the slave inferior region.

In another form the pump system further comprises a reservoir for water, and the valve means includes a high pressure relief valve and a low pressure relief valve, the reservoir being hydraulically connected to the hydraulic connecting conduit when either the high pressure relief valve or the low pressure relief valve are open.

In one embodiment, the master piston arrangement further comprises piston, sealing means extending around the master piston and the transmission means includes a

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-6pipe extending within the tubular structure and adapted to be reciprocatedly driven by the drive system.

Optionally, the pipe is connected to the conduit means for discharging water.

In another embodiment the slave piston arrangement further comprises a connecting pipe extending from the slave piston to a secondary piston at a remote location in the slave cylinder and a transverse watertight barrier fixed to the slave cylinder between the slave piston and i0 the secondary piston and providing a sliding seal for the connecting pipe as it passes through the barrier.

In one embodiment, the slave piston arrangement and the valve means provide for water discharge on both of the strokes of the master piston.

Advantageously, the valve means includes a one-way foot valve mounted at a bottom end of the slave cylinder.

Optionally, the slave piston may be biased e.g. by a compression spring in a direction corresponding to a downstroke by a biasing means.

In an important application, a water pump is provided comprising a windmill positioned adjacent a bore hole and a pump system as defined in any of the above paragraphs connected to be driven by the windmill and extending down the bore to pump water for discharge above ground level.

In a specific embodiment, the system is such that the valve means includes a first one way valve to permit water flow from above the slave piston and through the connecting pipe when the slave piston is driven downwardly and into a zone between the watertight barrier and the secondary piston, and a second one-way valve to permit water to flow from below the secondary piston into the connecting pipe and into the chamber between the secondary piston and the watertight barrier when the slave piston is

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~n 7 displaced downwardly, further inlet valve means being tprovided to admit water from the environment into the zone 0 below the secondary piston during such downward motion of the master and slave pistons.

A further embodiment is one in which a delivery pipe extends from a remote elevated location to be connected to an upper location in the second chamber and above a watertight partition, a secondary hydraulic connecting conduit Sis provided between a location in the second cylinder cI 10 below the water-tight partition, a connecting pipe extends from a valve-controlled port in the cylinder above the water-tight partition, through a sliding seal in the water-tight partition, through the slave piston towhich is it fixed, through a sliding seal in a lower water-tight partition which is fixed to a lower portion of the second cylinder, and to be connected to a secondary piston in a lowermost chamber of the second cylinder, the connecting pipe having a connection port to a zone between the lower water-tight partition and the secondary piston and a valve controlled lower port to control water flow into the connecting pipe to which the slave piston is moved downwardly.

The pump system may further include a flow control device adapted to be mounted at an elevated discharge location and receive water from the pump via a discharge pipe, the flow control device comprising a pneumatic head tank with a pneumatic valve adapted to be set to control a pneumatic head volume in the head tank in series with a water tank having a discharge valve at an upper discharge port biased towards a closed position; whereby when water pumped by the pump together with pressure applied by the pneumatic head tank exceeds a selected valve, the discharge valve opens to discharge pumped water, the I -8 pneumatic head tank providing a back pressure to maximize tseparation between the master piston and the slave piston 0 and to urge the slave piston to the bottom of its stroke 00 and at a speed to match the master piston movement.

_Brief Description of the Drawings r Figure 1 is a schematic front view of an upper part of a pump according to a first embodiment of the present CI 10 invention shown in an intermediate portion schematically; Figure 2 is a schematic front view of a lower half of the pump of Figure 1; Figure 3 is a schematic front view of a reservoir portion of the pump of Figures 1 and 2; Figure 4 is a schematic front view of a lower part of a pump according to a second embodiment of the present invention; Figure 5 is a schematic front view of a head system according to a third embodiment of the present invention.

Figure 6 is a schematic front view of a lower half of the pump of Figure 1 according to a fourth embodiment of the present invention.

Figure 7 is a schematic view of an overall system using the first embodiment of Figures 1-3 connected to a windmill; and Figure 8 is a schematic view of a second type of installation installed in a river situation and using a pump system according to the first embodiment of Figure 2.

Detailed Description of the Drawings Figures 1 and 2 illustrate a pump system 2 comprising a cylindrical lower delivery column 4, a lower delivery pipe 6, a cylindrical upper delivery column 8, an upper 9 pipe 10, a power pipe 12, a master unit 14, a slave unit 16, aone-way foot valve 18, a phase correction system 00 a reservoir pipe 21 and a reservoir 22 (shown in Figure 3).

The master unit 14 is mounted within the upper delivery column 8 and comprises a master piston 24 hydraulically dividing the upper delivery column 8 into a superior master chamber 26 and an inferior chamber 28.

O The master unit 14 includes the upper pipe 10 which S 10 extends through a seal 32 in an upper wall 30 of the superior master chamber 26 and through the master piston 24 which is fixed to the lower end of the upper pipe and moves with the upper pipe 10 as it slidably moves through the upper seal 32 when driven by a drive transmission.

The master pump 14 further comprises a main one-way discharge valve 34 mounted within a discharge portion of the upper pipe 10 and only allows water to pass in the discharge direction (shown by the arrow 36) into the reservoir pipe 21 'and towards the reservoir 22 (shown in Figure Other embodiments may omit the main one-way discharge valve 34.

The upper pipe 10 is driven by a reciprocating drive shaft 38, the drive shaft 38 being driven in turn by a crank (not shown) of a windmill. Alternatively drive from e.g. a power take-off of a tractor could be used. The radius of the crank, not the location of the upper seal 32, limits the vertical motion of the upper pipe The motion of the upper pipe 10 can be amplified by use of an optional lever (not shown) driven by the drive shaft 38 and driving the upper pipe The slave unit 16 is mounted within the lower delivery column 4 and comprises a slave piston 40, an

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injector piston 42 and a fixed watertight barrier 44 mounted intermediate the slave piston 40 and the injector piston 42. The slave piston 40 hydraulically divides the lower delivery column 4 into a slave superior chamber 46 and a slave inferior chamber 48. The injector piston 42 hydraulically divides the lower delivery column 4 into an injector superior chamber 50 and an injector inferior chamber 52. Thus, the watertight barrier 44 hydraulically 0 separates the slave inferior piston chamber 48 and the 1 0 injector superior chamber The slave unit 16 further comprises a lower pipe 54 extending through the slave piston 40, watertight barrier 44 and injector piston 42. The lower pipe 54 has the slave piston 40 fixed to it at an upper end 56 and the injector piston 42. fixed to it at an opposing lower end 58.

The lower pipe 54 is slidably mounted via a selfaligning seal through the watertight barrier 44 suchthat the slave piston 40 can translate within the lower delivery column 4, the limits of its vertical motion being controlled by the watertight barrier 44.

The injection piston 42, and thus the slave piston and pipe 54, are biased away from the watertight barrier 44 by a compression spring 59 which is mounted around the outside of the lower pipe 54 and has one end engaging the piston 42 and the other end engaging the barrier. The spring's specification, and in particular, the spring constant, is such that, in conjunction with the hydrostatic head from the lower delivery column, the injection piston 42 is returned to the bottom of its stroke as the master piston 24 moves downwardly.

A slave valve 62 and an injector valve 64 are mounted within the lower pipe 54 at its upper end 56 and lower end <D 11- 58, respectively. Both these valves 62 and 64 only allow twater to pass upwardly.

SThe foot valve 18 is mounted within the lower end of 00 Sthe lower delivery column 4 and only allows water to pass upwardly.

The power pipe 12 hydraulically connects the slave inferior chamber 48 with the master superior chamber 26 to (N transmit drive such that water is pumped upwardly.

When the pump system 2 is in use, drive shaft 3.8 of the windmill reciprocates vertically. By virtue of the mechanical connection between the drive shaft 38 and the upper pipe 10, the upper pipe 10 also reciprocates vertically driving the master piston 24 along the upper delivery column 8.

Thus, on the upstroke the master piston 24 displaces the water within the master superior chamber 26 into the power pipe 12 and then into the slave inferior chamber 48, thereby applying pressure to the lower surface of the slave piston 40 and displacing the slave unit 16 upwardly.

Upwards movement of the slave piston 40 causes upward motion of the injector piston 42 and suction in the injector inferior chamber 52 thereby causing the foot valve 18 to open and water to flow from the bore 68 into the injector inferior chamber 52. This water transfer continues to occur until the slave unit 16 reaches its upper limit and then the injector inferior chamber 52 holds a maximum volume of water and the spring 59 is compressed.

During this upstroke water is discharged into the discharge pipe 21 and the column and volume of water in pipe 6 simply moves up.

On the downstroke of the master piston 24, force is applied to the water in the inferior master chamber 28 and ~n-11- 58, respectively. Both these valves 62 and 64 only allow twater to pass upwardly.

0The foot valve 18 is mounted within the lower end of 00 the lower delivery column 4 and only allows water to pass upwardly.

The power pipe 12 hydraulically connects the slave inferior chamber 48 with the master superior chamber 26 to (Ni transmit drive such that water is pumped upwardly.

C When the pump system 2 is in use, drive shaft 38 of By v rt e o the (1 io the windmill reciprocates vertically. By virtue of the mechanical connection between the drive shaft 38 and the upper pipe 10, the upper pipe 10 also reciprocates vertically driving the master piston 24 along the upper delivery column 8.

Thus, on the upstroke the master piston 24 displaces the water within the master superior chamber 26 into the power pipe 12 and then into the slave inferior chamber 48, thereby applying pressure to the lower surface of the slave piston 40 and displacing the slave unit 16 upwardly.

Upwards movement of the slave piston 40 causes upward motion of the injector piston 42 and suction in the injector inferior chamber 52 thereby causing the foot valve 18 to open and water to flow from the bore 68 into the injector inferior chamber 52. This water transfer continues to occur until the slave unit 16 reaches its upper limit and then the injector inferior chamber 52 holds a maximum volume of water and the spring 59 is compressed.

During this upstroke water is discharged into the discharge pipe 21 and the column and volume of water in pipe 6 simply moves up.

On the downstroke of the master piston 24, force is applied to the water in the inferior master chamber 28 and

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12 I lower delivery pipe 6 to displace water into the superior tslave chamber 46 thereby forcing the slave unit 16 towards Sthe foot valve 18. The force generated by the downwardly moving master piston is complemented by the force generated by the compression spring 59. Water is also displaced from the inferior slave chamber 48, through the power pipe 12 and back into the superior master chamber CI 26.

When the slave unit 16 begins its downward motion, CI 10 there is greater water pressure in the inferior injector chamber 52 than in the lower pipe 54. This pressure differential causes the injector valve 64 to open and water to be transferred from the inferior injector chamber 52 into the above superior injector chamber 50. via a lateral aperture 65 in the wall of the pipe 54.

As the injector piston 42 applies pressure to the water contained in the superior injector chamber 50 and the lower pipe 54, a pressure differential arises between the water in the lower pipe 54 and the water in the superior slave chamber 46. This pressure differential causes a transfer of water from the superior injector chamber 50 into the superior slave chamber 46 through the slave valve 62. Thus the pump system is a double-acting system with water discharged on each stroke. The pipe 6 does not need to be rigid as it does not transmit any force but merely conducts flow of water. Accordingly an efficient system not requiring any precise alignment and capable of use at any angle may be provided.

The slave unit 16 also moves towards the foot valve 18 under its own weight. It should be noted that in other embodiments of the present invention, in which the lower delivery column 4 is disposed horizontally within a body

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S13 CI of water, this gravity force component will not be tpresent.

SThe phase correction system 20 (shown in Figure 1) is 00 for correcting the pump system 2 should the master unit 14 be out of phase with the slave unit 16. These out of phase 0 situations can arise from leakage of water past the seals and 32, or past any of the pistons 24, 40 or 42.

c, The phase correction system 20 comprises a tank an inlet pipe 72 and an outlet pipe 74, a negative CI 10 pressure relief valve 76 and a high pressure relief valve 78. The inlet pipe 72 and the outlet pipe 74 meet at a junction 80, the junction 80 being hydraulically connected to the power column 12 so that adjustment can automatically occur for compensation of any tendency for out-of-phase conditions to arise.

If the master piston 24 were to be near the top of its stroke but the slave unit 16 were to be near at the bottom of its stroke, there would be an increased volume of water in the inferior piston chamber 28, the pipe 6 and the superior slave chamber 46 and a decreased volume of water within the power pipe 12. In this situation, as the master piston 24 moves downwards, a suction will develop within the power pipe 12 causing the negative pressure relief valve 76 to open. This allows water to flow from the reservoir tank 70, through the outlet pipe 74 and into the power pipe 12. When the master piston 24 begins its journey upwards, normal in-phase pumping motion of the entire pump system 2 would resume.

If the opposite situation developed where the master piston 24 is near the bottom of its stroke and the slave unit 16 is near the top of its stroke, there is an excess of water in the power pipe 12 and a corresponding deficiency of water in the inferior master chamber 28 and I

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14 superior slave chamber 46. Therefore, as the master piston 24 rises, the pressure in the power pipe 12 tends to increase to beyond normal operating level and the high pressure relief valve 78 opens. The excess water in the power pipe 12 is then able to flow through the inlet pipe 72 into the tank 70 and normal in-phase operation of the pump system 2 can resume.

There are many advantages associated with this embodiment of the present invention. The lower delivery column 4 does not have to be located substantially vertically beneath the windmill since the slave unit 16 is driven hydraulically rather than by a chain of metal rods.

This allows the windmill to be positioned at a high winds location, for example, on top of a hill and slave unit 16 may be very remote in location.

As this embodiment of the present invention does not require a chain of rods to provide power to the slave unit 16, the type of damage, friction and wear of prior art windmill pump systems is obviated. Thus, a further -advantage is obtained in that a downward force in addition to the head pressure can be applied to the slave unit 16 by the master piston 24 and an efficient double-acting system can be provided.

Another advantage is obtained by this embodiment in that cheap, flexible and corrosion free polythene pipe (as used extensively in modern agricultural plumbing) can be used to conduct water from a submersible pump in place of expensive, rigid and rust-prone galvanized steel piping or expensive rigid, thick-walled PVC pipe which is used in conventional windmill systems. As all force is transmitted hydraulically in the present embodiment, there is no need for any pipes forming the power pipe 12 or the lower delivery pipe 6 to be either rigid or vertical in contrast

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15 to conventional windmill systems utilizing rod ,transmission, a major constraint on the possibilities for use of conventional windmill pumping systems.

Flexible plastic pipe cannot be used in conventional systems.- Rather, rigid pipe, such as that made of galvanized steel, is required to keep the pump cylinder stationary and resist compression force as the plunger is pulled upwards by the force of the crank transmitted through the chain of rods. The rods are under tension on the upstroke while the steel pipe is under compression.

Polythene pipe distorts easily under such compression stress. Yet there is no requirement in the present embodiment for the polythene pipe to resist substantial compression, or tension as the weight of the slave system 66 suspended down a bore hole can be carried independently of the polythene pipes used for the power pipe 12 and lower delivery pipe 6, by cables of stainless steel, kevlar or other suitable material.

Another advantage is obtained by this embodiment in that less resistance, in the form of interior and/or weight, needs to be overcome for the windmill to become operational. This is because the significant mass of the conventional chain of rods is absent. Only the lesser resistance of the variable main one-way discharge valve 34, if one is fitted, the compression spring 59 and/or the head pressure supplied by the reservoir 22 need be overcome for the windmill turbine to start.

The pump system 2 also can have inherent advantages over conventional windmill pumps with regards to the cost of servicing and replacement of parts since parts are not damaged by frictional contact with the chain of metal rods. Withdrawal of the system from the bore for I 16 servicing is also less time-consuming and labour-intensive than with conventional systems.

The only mechanical advantage obtainable in some windmills is that obtainable by variation of the turbine radius to crank radius ratio. However, an inherent possibility with embodiments of the present invention is that gearing of the pump system 2 can be achieved by the addition of a lever between the drive shaft 38 and the upper pipe i0. Such a levered gearing system can be IO configured in either a second or third order lever arrangement. If the windmill has a quadrapod tower, the lever can be anchored by a hinge joint at one end to a leg of the tower frame, and disposed diagonally across the inside of the tower towards the opposite leg. Such a gearing system enables a wide variety of stroke lengths for a fixed crank radius on an established mill, and a wide variety of water volumes delivered per cycle. Such a gearing system may be used advantageously where there is a considerable distance between the drive pump 14 and slave pump 16.

The pump system 2 is also easily retrofittable to conventional windmills.

Figure 3 shows an optional reservoir 22, into which water passes from the upper pipe 10, when the pump is in use. If a variable main one-way discharge valve 34 is not fitted, then the system relies on a pneumatic head provided by the pneumatic head tank 104 and/or hydraulic head as provided by the reservoir 22 to provide the force to return the slave system 66 to the bottom of its stroke.

Whatever system is used must provide sufficient force to return the slave unit 16 to the bottom of its stroke fast enough to keep pace with the master piston 24 at its

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17 0 maximum frequency of oscillation, as will occur in high twinds and fast windmill speeds.

0 Figure 4 shows schematically modifications for a 0o second embodiment comprising a pump system 2A where like numerals to those used in the previous embodiment denotes like parts. In the first embodiment of Figures 1, 2 and 3 the pump system 2 utilises the lower delivery pipe 6 to carry both the pumped water upwards and to provide downwards hydraulic pressure onto the slave unit 16.

In some situations, where it is not practical to utilise a pneumatic or hydraulic head, the pump system 2A may be used. In this case, the upper pipe 10 of the master pump does not transfer water through the master piston which is closed. The main one-way discharge valve 34 (Fig 1) is not used and instead the lower end of the reservoir pipe 21 is hydraulicallY connected to the lower delivery pipe 6A (Fig 4).

The pump system 2A comprises, in addition to the features of the first embodiment, a second power pipe 82, a second watertight barrier 84, an extended lower pipe 54A, and a second upper barrier chamber 86. The upper watertight barrier 84 is fixedly mounted within the lower delivery column 4A, and hydraulically divides the superior slave piston chamber 46A and the upper barrier chamber 86.

The lower pipe 54A also extends through and is slidably mounted in the upper watertight barrier 84 via a selfaligning barrier seal 88 set into the watertight barrier 84. There is a similar self-aligning barrier seal set into the watertight barrier 44A.

The second power pipe 82 hydraulically connects the superior slave chamber 46A and the inferior master chamber 28. The lower pipe 54A is hydraulically connected to the lower delivery pipe 6A with a one-way slave valve 62A to 18 c-I control water flow to upward discharge. The delivery pipe t6A joins the reservoir pipe 21 to deliver water to the Sreservoir 22, but the delivery pipe 6A is not used to 00 Stransmit any operating force. All force delivered to the upper surface of the slave piston 40A is transferred via the second power pipe 82.

Figure 5 shows another embodiment used as a c- substitute for or in conjunction with the arrangement of Figure 3 and suitable for use with the pump system 2, 2A 1 0 of Figure 4 or pump system 16B of Figure 6. Figure shows a head system 92 disposed between the reservoir pipe 21B and upper reservoir pipe 94, the upper reservoir pipe 94 discharging water directly into the reservoir 22B. The arrow 96 indicates the direction of the water flow. The head system 92 comprises a pneumatic head tank 98 and a weighted valve tank 100. The pneumatic head tank 98 is a closed tank with a pneumatic head valve 102 which allows the pneumatic head volume 104 in the pneumatic head tank 98 to be increased or decreased. The weighted valve tank i00 comprises a weighted valve 106 with a weight 108 configured in the form of a copper pipe having a closed lower end, the weight of which may be adjusted by the addition or subtraction of lead pellets from within the sealed copper pipe. A common float valve can also be used as an adjustable pressure relief valve.

Water can flow through the weighted valve 106 when sufficient force is imposed by applied pressure the water entering the weighted valve tank 100 from both the reservoir pipe 21B and the pneumatic head tank 98. The air pressure of the pneumatic head 104 should be set such that it is sufficient to cause maximum separation between the master piston 24 and slave piston 40. The pressure should also be sufficient to return the slave unit 16 to 19 the bottom of its stroke fast enough to keep up with the master piston 24 at its maximum oscillation frequency.

00 The main one-way discharge valve 34 of the first embodiment described simply represents an alternative way of achieving the functionality of the weighted valve 106.

However, the advantage of the weighted valve 106 is that it is adjustable in terms of release pressure, and can be C- rugged, cheap and easily manufactured.

Figure 6' illustrates a fourth embodiment of the 1 0 invention wherein the pump system 2 of the first embodiment is provided with an alternative lower section.

The upper section of the resulting pump system 2B is similar to that of the first embodiment but the delivery pipe 6 (not shown) is simply connected by flexible tubing to a lower lateral delivery pipe 118. Like reference numerals to those used in previous embodiments denote like parts.

In some situations where t:he water depth at the bottom of a bore or other source is not great, and it is undesirable to have water enter the pump system from its lowest extremity, the pump system of Fig 6 incorporating a slave unit 16B incorporating a pump may be used. The embodiment of Fig 6 thus has a ground water inlet 111 located at an upper end of the slave unit 16B and positioned below water level 113. As can be provided with the slave units shown in Figs 2 and 4, the slave unit 16B of Figure 6 has mounting eyebolts 115 to which suspension cables 117 are attached. The slave unit is hydraulically connected to a remote master unit by flexible hoses connected to a water discharge pipe 118 and power pipe 12B.

A slave'pump unit 16B comprises a cylinder 11ii0 having upper and lower wall portions l1OA and lIOB and a fixed 20 cI watertight barrier 44B. A movable slave assembly 66B is tmounted within the cylinder and comprises a slave piston S40B, travelling connecting pipe 54B, and a lower injector 00 piston 112. The slave piston 40B hydraulically divides the cylinder 110 into a superior chamber 46B and an inferior 0 chamber 48B. The injector piston 112 hydraulically divides the lower (portion 110B of cylinder 110) into an intermediate chamber 114 and a lower-most chamber 116. The watertight barrier hydraulically separates the C- 10 intermediate chamber 114 and the inferior slave chamber 48B. A delivery pipe 118 hydraulically connects to the intermediate chamber 114 of the cylinder while the power pipe 12B connects to the upper portion 110A of the cylinder.

The lower injector piston 112 is biased away from the watertight barrier 44B by a compression spring 59B. which is mounted around the outside of the travelling connector pipe 54B and has one end engaging the lower injector piston 112 and the other end engaging the barrier 44B. The spring specification, and in particular, the spring constant is such that, in conjunction with the hydrostatic head provided by the deep delivery pipe 118, the lower piston is returned to the bottom of its stroke as the master piston 24 moves downwardly.

The connector pipe 549 is sealingly and slidably mounted through the watertight barrier 44B via a selfaligning barrier seal 60B such that the injector piston 112 and slave piston 40B can translate within the cylinder 110, the limits of their vertical motion being fixed by the watertight barrier. A one-way valve 64B is mounted within the lower pipe 54B at its upper end 56B and only allows water to pass downwardly into the intermediate chamber 114. The injector piston 112, connector pipe 54B,

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-21 slave piston 40B and valve 64B comprise a slave system t66B. An inlet valve 122 is provided at the top of the 00 cylinder 110 and only allows water to pass downwardly into the superior slave chamber 46B. The power pipe 12B hydraulically connects the inferior slave chamber 48B with -,the superior master chamber 26.

Fig 6 shows the slave system 66B in an intermediate C- position, in which the slave piston limit portions are shown as 140B and 141B schematically. Fig 6 also shows CI 10 arrows to indicate upward movement of the slave system with double-headed arrows indicating water displacement.

In a similar mode of operation to that of the first embodiment, on the upstroke of the master piston 24, water is displaced into the power pipe 12B and then into the below inferior slave chamber 48B, thereby applying pressure to the lower surface of the slave piston 40B and displacing the slave system 66B upwardly towards the valve 122. Since the inlet valve 122 is one-way and driven closed, water within the upper portion llOA of cylinder 110 is forced downwardly through the slave valve 64B, the connecting pipe 54B and into the intermediate chamber 114.

Simultaneously, water from the chamber 114 is forced by the injector piston 58B into the delivery pipe 118. The slave system 66B reaches the top of its stroke when the lower piston 112 fully compresses spring 59B and is adjacent the watertight barrier 44B.

The volume of water injected into the pipe 118 is the sum of the volume reductions in the chambers above both the slave piston and the injector piston.

On the downstroke of the master piston 24, the load of water in the delivery pipe 118 bearing on the supper surface of the injector piston 112, the return force of the compression spring 59B, the weight of the slave system 22 and the load of water from the ground source tending to open valve 122 and load the upper face of slave piston causes the slave assembly 66B to descend. This causes the volume of water required to fill the expanding injector chamber 114 to be drawn from pipe 118 and slave piston 40B to push water back up the power pipe 12 in a volume which corresponds with that drawn into the superior chamber above the master piston.

The injector ,piston 112 moves down towards a rubber annular seat 124 mounted on the bottom of the cylinder 110. This buffering may be assisted by a buoyant ball (not shown) acting as a valve to close the aperture created by the seat when the injector piston 112 reaches the bottom of its stroke and has.expelled a maximum of water from the lowermost chamber 116.

The next volume of water expelled into the pipe 12B is equal to the volume reduction in the slave superior chamber 46B during an upward stroke.

Any one of the pump systems 2, 2A and 2B can be fitted with a device which would enable a water turbine or windmill turbine to drive the system but free wheel until a suitable rotational speed is achieved. This device is not shown but would incorporate a mechanism which allows water to pass directly from the power pipe 12 to the lower delivery pipe 6, thus bypassing the slave piston 40. The mechanism is regulated by a bypass valve which remains closed until a suitable turbine rotational speed is achieved. The bypass valve can be controlled by either a centrifugal governor driven by. the turbine, or a valve configured in such a way that it opens at slow water speeds but closes at high water speeds. For example, such a valve can be formed from swing valves vertically aligned in series, with their flow directions opposed, and with 23 one weighted so that it remains open to water entering from the power column 12 (below certain threshold values of flow rate and pressure).

Referring now to Figure there is illustrated a hydraulically driven windmill pumping system comprising a conventional windmill 200 installed above ground level 201 and driving a vertically reciprocating a drive rod 202 which connects to a hydraulic master cylinder unit 203 in accordance with Figure 1. A flexible connection pipe 204 extends from the master unit 203 to be passed down a cased bore hole having a casing 205 to be connected to a slave unit 206 at a lower region of the bore hole and immersed in a aquifer 207. The slave unit 206 includes both a slave cylinder 215 and injector cylinder 216 and is based on the principles disclosed with reference to Figure 2.

Figure 7 illustrates an above-ground water storage tank to which water may be pumped through flexible pipe 209. Figure 7 illustrates an optional hydrostatic head pipe 210 which is conveniently formed of pressure rated rigid PVC pipe, into which water is pumped through flexible pipe 211. The upper end 214 of the PVC head pipe is open to the air and connected through an inlet 212 into a down pipe 213 which leads to the flexible delivery pipe 209.

Referring now to Figure 8, an external view of the system as disclosed in Figure 2 for installation in a river having a bed 300 and a water level 302 is illustrated. A slave cylinder 304 is mounted in a junction block 306 and below which the injector cylinder 308 is mounted and connects to an inlet foot valve 310.

The slave cylinder 304 is connected to a discharge pipe 312 which conducts water that has been pumped upwardly and away to a discharge location. Figure 8 also

I~

24 C illustrates the water power pipes 314 and 316 both tcorresponding with (a divided) pipe 12 as shown schematicallY in Figures 1 and 2.

00 In the claims which follow and 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, i.e. to specify the presence of the stated features but 1 0 not to preclude the presence or addition of further features in various embodiments of the invention.

Claims (12)

1. A pump system having transmission means to receive reciprocating drive from a drive system, and a tubular system adapted to extend from the transmission means to a remote location below the water level in a water source, the tubular system providing l a master piston arrangement which includes a master piston and a master cylinder providing a S 10 first chamber through which the master piston is adapted to be reciprocatedly driven by drive from the transmission means, a slave piston arrangement which includes a slave piston and a slave cylinder providing a second chamber through which the slave piston is adapted to be driven in a manner corresponding to movement of the master piston, a hydraulic connecting conduit interconnecting the first chamber and a second chamber so that the master piston and slave piston move correspondingly, a pump adapted to be mounted at the remote location to be submersed in the water and driven by the slave piston to pump water through the tubular system, conduit means for ducting water pumped by the pump to a discharge location, and valve means to cause water to be pumped up through the conduit means.

2. A pump system as defined in claim i, in which, when orientated for installation down a bore hole, there is defined a master superior region within the first chamber and above the master piston, a master inferior region 26 within the first chamber and below the master piston, a tslave superior region within the second chamber and above 0the slave piston, a slave inferior region within the 0o second chamber and below the slave piston, and wherein the hydraulic connecting conduit connects the master superior region to the slave inferior piston region. CI

3. A pump system as defined in claim 2 and, further comprising a reservoir for water, and the valve means NI 10 includes a high pressure relief valve and a low pressure relief valve, the reservoir being hydraulically connected to the hydraulic connecting conduit when either the high pressure relief valve or the low pressure relief valve are open.

4. A pump system as defined in claim 2 or claim 3, wherein the master piston arrangement further comprises piston sealing means extending around the master piston and the transmission means includes a pipe extending within the tubular structure and adapted to be reciprocatedly driven by the drive system. A pump system as defined in claim 4, wherein the pipe is connected to the conduit means for discharging water.

6. A pump system as defined in any one of claims wherein the slave piston arrangement further comprises a connecting pipe extending from the slave piston to a portion of the pump in the form of a secondary piston at a remote location in the slave cylinder and a transverse watertight barrier is fixed the slave cylinder between the slave piston and the secondary piston and provides a sliding seal for the connecting pipe as it moves through I~ -27 C the barrier to transfer movement from the slave piston to tthe secondary piston. 00 S7. A pump system as defined in any one of claims 2-6, and wherein the slave piston arrangement and the valve means provide for water discharge on both of the strokes of the master piston.

8. A pump system as defined in any one of claims 2-7, NI 10 wherein the valve means includes a one-way foot valve mounted at a bottom end of the slave cylinder.

9. A pump system as defined in any one of claims 2-8, wherein the slave piston is biased in a direction corresponding to a downstroke by a biasing spring. A pump system as claimed in any one of claims 2-9 and wherein the valve means includes a first one way valve to permit water flow from the above the slave piston and through the connecting pipe when the slave piston is driven downwardly and into a zone between the watertight barrier and the secondary piston, and a second one-way valve to permit water to flow from below the secondary piston into the connecting pipe and into the chamber between the secondary piston and the watertight barrier when the slave piston is displaced downwardly, further inlet valve means being provided to admit water from the environment into the zone below the secondary piston during such downward motion of the master and slave pistons.

11. A pump system as claimed in claim 10, further comprising a discharge pipe for pumped water extending 28 from the second chamber through the master piston and through a non-return valve to a final delivery pipe at an elevated location. oo00

12. A pump system as claimed in any one of claims 2-8 C wherein a delivery pipe extends from a remote elevated location to be connected to an upper location in the CN second chamber and above a water-tight partition, a Vsecondary hydraulic connecting conduit is provided between a location in the second cylinder below the water-tight partition, a connecting pipe extends from a valve- controlled port in the cylinder above the water-tight partition, through a sliding seal in the water-tight partition, through the slave piston to which is it fixed, through a sliding seal in a lower water-tight partition which is fixed to a lower portion of the second cylinder, and to be connected to a secondary piston in a lowermost chamber of the second cylinder, the connecting pipe having a connection port to a zone between the lower water-tight partition and the secondary piston and a valve controlled lower port to control water flow into the connecting pipe to which the slave piston is moved downwardly.

13. A pump system as claimed in any one of claims 1-11, and further including a flow control device adapted to be mounted at an elevated discharge location and receive water from the pump via a discharge pipe, the flow control device comprising a pneumatic head tank with a pneumatic valve adapted to be set to control a pneumatic head volume in the head tank in series with a water tank having a discharge valve at an upper discharge port biased towards a closed position; whereby when water pumped by the pump together with pressure applied by the pneumatic head tank 29 exceeds a selected valve, the discharge valve opens to discharge pumped water, the pneumatic head tank providing a back presume to maximize separation between the master piston and the slave piston and to urge the slave piston to the bottom of its stroke and at a speed to match the master piston movement.

14. A pump system as claimed in claim 13, wherein the discharge valve comprises a weighted valve having a variably weighted suspended element immersed in the water tank. A pump system as claimed in any one of claims 2-11, wherein the pump, valve means and slave piston arrangement are provided in a slave unit which is adapted to be suspended to be immersed in a body of water and having a valved water inlet at an upper end of a tabular structure to admit water into an upper chamber responsive to downward motion of the slave piston, which is connected by a rigid connecting pipe to a secondary piston located below a water-tight partition through which the connecting pipe is slidably mounted, each of the slave piston and secondary piston moving in respective upper and lower slave cylinder portions, the conduit means being connected to the lower slave cylinder portion and the hydraulic connecting conduit being connected from the upper slave cylinder portion and the hydraulic connecting conduit being connected from the upper slave cylinder below the slave piston to above the master piston, the connecting pipe has a port for water flow between the connecting pipe and the lower slave cylinder and the valve means including a one-way valve in the connecting pipe to allow water to flow down the pipe from the upper end of the tubular (N structure only when the slave piston is displaced upwardly twhereby water is pumped into the conduit means. 00

16. A pump system substantially as herein before described with reference to Figs 1 to 3 or as modified O according to any one of Figs 4, 5 or 6. i 17. A water pump comprising a windmill positioned adjacent a bore hole and a pump system as claimed in any one of the preceding claims connected to be driven by the windmill and extending down the bore to pump water for discharge above ground level.