WO1993011361A1

WO1993011361A1 - Pump

Info

Publication number: WO1993011361A1
Application number: PCT/AU1992/000654
Authority: WO
Inventors: Neville Tyson Warren
Original assignee: Horwood Bagshaw Australia Limited; Asbeck Pty. Limited
Priority date: 1991-12-04
Filing date: 1992-12-04
Publication date: 1993-06-10

Abstract

A pump having at least one pumping chamber (15) with uni-directional inlet and outlet valves (16, 17) for pumping a fluid in one direction. An auxiliary fluid is provided in a branch tube (10) opening into each pumping chamber (15), forming an interface (30) with the fluid being pumped in the branch tube (10). Reciprocation of the auxiliary fluid causes alternating suction and discharge action in the pumping chamber.

Description

PUMP

This invention relates to a pump and is more specifically, although not exclusively, concerned with a pump useable to pump water contaminated with grit or sediment from deep bore holes and other locations where access may be restricted or the pump is required to operate for long periods without maintenance- Water which is contaminated with grit, sediment or other materials which abrasive wear of pumping equipment over prolonged periods of use is hereinafter referred to as "unclean" water to distinguish it from "clean" water which is substantially free from such materials and can be pumped almost indefinitely without significant wear of the pumping equipment. British patent specification No. 1,221,144 describes a pump of simple construction suitable for pumping unclean water as above defined. It has a rigid cylindrical pumping chamber containing a bladder inflatable with an auxiliary liquid and having unidirectional valves at the upper and lower ends of the chamber respectively. These valves allow the pumped water to flow upwardly through the chamber only. A cyclically-operated pressure source of the auxiliary fluid at a remote location, is connected by a tube to the bladder. When it expands the bladder, the water in the chamber is forced out of the upper unidirectional valve, and when it contracts the bladder the upper valve closes and water is drawn into the chamber through the lower valve. A disadvantage of the pump described in the British patent is that the bladder becomes worn over a period of time which is greatly shortened if the unclean water contains an abrasive material such as sand.

The present invention provides a pump, comprising a pump chamber incorporating a uni-directional valve arrangement enabling flow of a pumped fluid into and out of the pump chamber in one direction, a conduit having one end opening into the pump chamber and another end connected to a drive means arranged to impart a reciprocating action to an auxiliary fluid within the conduit, the arrangement being such that, in operation, reciprocating action of the auxiliary fluid in the conduit causes pumped fluid to flow through the pump chamber in the one direction.

The valve arrangement preferably comprises an inlet valve for allowing fluid to be drawn into the chamber and an outlet valve for allowing fluid to be ejected from the chamber. The reciprocating action of the auxiliary fluid in the conduit provides a force which causes pumped fluid to be drawn into the chamber through the inlet valve when the auxiliary fluid is being sucked up the conduit and causes fluid already in the chamber to be ejected from the chamber through the outlet valve when auxiliary fluid is being pushed down the conduit.

Preferably, the arrangement is such that a fluid/fluid interface is formed between the pumped fluid and the auxiliary fluid in the second conduit, the interface being reciprocated within the second conduit in response to the action of the drive means.

The fluids are preferably both liquids. Both fluids may be water, or one may be water and the auxiliary fluid may be another liquid, such as oil, for example. The auxiliary liquid is preferably "clean", in the sense that it does not contain abrasive materials likely to effect wear on the parts of the pump it is in contact with.

The pump may be applied to pump liquids from bore holes. In shallow bore holes, the drive means may be positioned at the surface of the bore hole. In deeper bore holes, however, it is preferred that a power transmission device is positioned within the bore hole to ensure the pumping action provided by the reciprocation of the auxiliary fluid is maintained.

A damping means is preferably connected to the pump chamber for enabling a more continuous flow of pumped fluid. In a preferred arrangement, a pair of pump chambers are preferably provided with their outlets connected together such that fluid pumped through the chambers may be pumped to the surface, where the pump is operated in a well or bore hole. Respective conduits are connected to each pump chamber, containing respective auxiliary fluids and the auxiliary fluids in each conduit are preferably reciprocated in anti-phase, such that when one of the chambers is ejecting fluid through its outlet the other of the chambers is drawing fluid in through its inlet. The drive means for this preferred arrangement preferably comprises a double action piston arrangement, the reciprocation of which causes the anti-phase reciprocation of the auxiliary fluids in the respective conduits.

The damping means, preferably comprises a damping chamber containing a pressurised gas, fitted to the outlet of the pump chambers. The gas in the damping chamber may be separated from the pumped fluid by a diaphragm. As pumped fluid is forced from the connecting pump chamber the pressurised gas absorbs some of the energy of the pumped fluid. While the pump chamber is undergoing the following suction stage, the energy absorbed by the pressurised gas is transferred to the water in the damping chamber, forcing it from the pump. The damping chamber preferably has a unidirectional valve, on each of the pipes leading to and from it. More damping chambers may be added to the pipe leading to the surface of the bore, as the pumping head of the pump increases.

The damping chamber assembly has the overall effect of:

- providing a more continuous flow of water from the pump; and - reducing the shock loadings produced by the pumping increasing the overall working life of the pump.

The present invention further provides a method of pumping fluid from a well along a first conduit incorporating a valve mechanism allowing flow of pumped fluid in one direction along the first conduit and having a second conduit with one end opening as a branch inlet into the first conduit, comprising the steps of providing an auxiliary fluid in the second conduit such that an interface is formed between the auxiliary fluid and the pumped fluid from the first conduit, and reciprocating the interface within the second conduit to cause fluid to be pumped along the first conduit by virtue of the reciprocating action.

The fluids are preferably liquids and the auxiliary fluid is preferably "clean".

In a preferred embodiment the pump comprises a pumping chamber having unidirectional inlet and outlet valves allowing flow of a first unclean liquid (as above defined) between them in one direction only, and a branch inlet attached to one end of a tube having its other end- portion upright and connected at its upper end to a cyclically-operated pressure source of a second clean liquid (as above defined) which forms a liquid-to-liquid interface with the first liquid, the displacement volume of the source being less than the effective volume of the upright end-portion of the tube so that the interface formed between the two liquids is confined to reciprocating vertical movement in the upright portion of the tube when the source is operated to drive the pump.

In carrying out the invention both of the liquids may be water. In this case the two liquids are naturally miscible and the interface occupies a short length of the tube. However the working parts of the pump required to have good seals are only in contact with the clean liquid so that wear is greatly reduced. Also a cheaply constructed pump using simple leather-bucket seals on the piston is possible. Suitably the pump is provided with means enabling it to be primed from time-to-time with fresh clean water, and for any air which collects in the system over a prolonged period to be purged out of it.

The upright end-portion of the tube in which the reciprocation of the interface takes place preferably slopes down towards an outlet through which solid matter entrained in the unclean liquid can precipitate out during periods that the pump is not in use. Although passage of the unclean water through the valves does inevitably cause some wear, these parts do not have to maintain good seals and can be robustly constructed so that the wear on them is minimal.

The invention may be used with a clean liquid, such as oil, which is usually immiscible with water. This has the advantage that better lubrication of the working parts of the pump can be obtained. There are, however, many areas of the world where oils are not readily obtainable and a simply constructed pump using only water as the lubricant and having a relatively long life, represents an important step forward.

In a further preferred embodiment the pump comprise a pumping chamber having unidirectional inlet and outlet valves allowing flow of a pumped or first liquid between them in one direction only, and a branch inlet attached to an upper end of one limb of a J-tube having its upright stem connected at its upper end to a cyclically operated pressure source of a second liquid which is immiscible with the first liquid, the displacement volume of the source being less than the effective volume of the J-tube stem so that the liquid interface formed between the two liquids in the J-tube stem is confined to reciprocating vertical ov ÷ment in the stem when the source is operated to drive the pump. Preferably the second liquid is a clean liquid such as oil, for example olive oil, and the first liquid is unclean water.

If desired, contact between the two liquids at the interface can be reduced by providing a member between them which floats on the pumped liquid and sinks in the second liquid. The member should not totally isolate the two liquids and should be a slack fit in the J-tube stem so that air bubbles can travel upwardly past it. Also it should not give any additional resistance to the operation of the pump. The purpose of using a J-tube shape is to confine the interface between the two liquids to a position where the second liquid does not enter the pumping chamber if a leak occurs, while ensuring that any gas which dissolves out of the pumped liquid does not form an air lock which might impede pumping. Any type of tube shape could be used which performs this function.

If the pump is required to operate at a depth of more than about seven metres beneath ground level, it is preferred to provide it with a power transmission device in the form of a reciprocating power-transmitting unit located in the bore hole about seven metres or less above the level of the pump. The unit is operated by power transmitted through vertical power lines extending to the top of the bore hole and which may have virtually any desired length. These lines may carry hydraulic fluid which is driven by a cyclically operated power source at or above ground level. The power source may be a man ally operated pumping device or a wind operated mechanism. The power source causes the unit to operate to provide hydraulic liquid under pressure alternately to the stems of the respective conduits to operate the pump as explained above. One form of power-transmitting unit comprises a double-headed floated piston assembly mounted inside a cylinder and having its piston rod interconnecting the two pistons, passing through a seal in a centre partition in the cylinder. Features and advantages of the present invention will become apparent from the following description of embodiments thereof, by way of example only, with reference to the accompanying drawings, in which: FIGURE 1 is a schematic cross-sectional diagram showing a pump system configuration in accordance with an embodiment of the present invention, for drawing 'water from a shallow bore hole of less than seven metres depth; FIGURE 2 is a schematic cross-sectional diagram showing a pump system configuration, in accordance with a further embodiment of the present invention, for drawing water form a bore hole of more than seven metres depth; FIGURE 3 is a schematic cross-sectional diagram showing a pump system configuration, in accordance with yet a further embodiment of the present invention using only clean and unclean water as the auxiliary pumped liquics without there being a risk of abrasive wear of working parts of a piston-and-cylinder pump unit. Figure 1 shows a bore hole 1 sunk in the ground and containing water 2. Ground level is shown at 3. A prime mover 4, conveniently a windmill, provides a reciprocating drive to a piston rod 6 driving a double- sided piston 7 sliding sealingly in a closed cylinder 8. Opposite end-portions of the cylinder 8 are connected by outlets 9 to respective J-tubes 10 each having an upright stem 11 and an upright limb 12. The lower portions of the J-tubes 10 form part of a pump assembly 13 located close to the bottom of the bore hole 1 and resting on a base 14.

The assembly 13 has two upright cylindrical pump chambers 15 having unidirectional lower valves 16 and upper valves 17. The lower valves 16 open upwardly from the lower portion of the bore hole a short distance above its floor, and the upper valves 17 open into plenums 20 connected to respective ends of a connecting tube 21 having an upwardly extending branch pipe 22 which carries the pumped water out of the bore hole, as shown.

The upper ends of the limbs 12 of the J-tubes open into the chambers 15 immediately beneath the plenums 20. The upper ends of the chambers 15 arch upwardly so that any gas which dissolves out of the water in the bore hole ascends through the plenums 17, pipes 21 and 22 with the water discharged from the bore hole, and does not enter the stem 11 of the J-tubes 10.

The end-portions of the cylinder 8 and the bulk of the stems 11 of the J-tubes 10 are filled with olive oil which is immiscible with water. The internal volume of each stem 11 is substantially greater than the aggregated volumes of the end-portions of the cylinder 8. The quantity of olive oil present is sufficient for a water- oil interface 30 to be formed in each stem 11, spaced sufficiently above its lower end to ensure that, when the piston 7 is reciprocated in the cylinder 8, the vertical movement of the interface 30 is always confined to the stem 11 of the J-tube 10.

When the pump system is operating, the prime mover 4 causes the piston 7 to reciprocate in the cylinder 8. This causes the oil to be forced down one of the J-tubes 10 while simultaneously being sucked up the other J-tube. This results in water from the shorter limb 12 of the J- tube being forced into one of the pumping chambers 15, causing its lower valve 16 to close and its upper valve 17 to open, and being sucked from the second chamber 15 into the shorter limb of the other J-tube, causing its lower valve 16 of the second chamber to open and its upper valve 17 to close. The water charge in one of the chambers 15 is therefore forced upwardly through the pipe 22 while the other chamber is receiving a fresh charge of water from the bore hole 1.

There is a damping chamber 18_. connected to each connecting tube 21 leading from the pumping chambers 13. The damping chamber 18 contains a pressurised gas 19. The water in the damping chamber 18 may or may not be separated by the pressurised gas 19 by a diaphragm. When water is pumped into connecting tube 21, the majority of ^• it passes through the one-way valve 5 into pipe 22, however some of it is pumped into the damping chamber 18. The pressurised gas 19 in the damping chamber 18 absorbs some of the shock loadings produced when water is forced out of the pumping chamber, 15. When water is being sucked into the pumping chamber 15, the energy stored in the pressurised gas 19 is transferred to the water in the damping chamber 18, forcing it back into connecting tube 21, and through the valve 5, into pipe 22.

The above described pump has the advantage that the oil in the cylinder 8 and the bulk of the length of the J-tube, prevents sedimentation from the water, which in bore holes is commonly extremely "hard" through the dissolution of mineral salts in it, depositing on working surfaces of the chamber 8 or interfering with the operation of the piston 7. The absence of a flexible membrane or bladder in the chambers 15 ensures a longer life for the pump system between periods of maintenance. If, over a protracted period, air does accumulate in the cylinder, this can be bled away through a valve- controlled air outlet (not shown) .

The embodiment of the invention shown in figure 2 is used for bore holes more than seven metres deep. Parts of the pump system identical to corresponding parts of figure 1 correspondingly numbered and will not be again described.

In figure 2 the outlets 9 of the cylinder 8 are connected by ___spective pipes 31 to opposite ends of a power-transmitting unit located inside the bore hole and comprising an upright cylinder 32 located not more than seven metres above the pumping chambers 15. The lengths of the pipes 31 can be very long indeed, they serve only to transmit hydraulic pressure generated in opposite end- portions of the cylinder 8 to chambers 33 disposed respectively in opposite end-portions of the cylinder 32.

The cylinder 32 contains a double-headed floating piston assembly 34 comprising a piston rod 35 passing slidably through a seal in a centre partition 36 in the cylinder 32. Te two end-chambers each have a lateral branch outlet 37 disposed adjacent the upper __ lower surfaces of the partition 36 and communicating respecti aly with the upper <^■-ds of the stems 11 of the J-tubes 10. The end-chambei >3 are filled with the same oil as the cylinder 8 and which is preferably olive oil. In operation of the embodiment of figure 2, the piston assembly 34 is reciprocated in synchronism with the movement of the piston head 7. This is achieved by the difference in hydraulic pressure occurring between the outlets 9 during the reciprocation of the piston head 7, and is virtually unaffected by the vertical lengths of the pipes 31 if their inherent resistance to the flow of hydraulic fluid through them is ignored. Movement of the piston assembly 34 produces an increase in pressure in one or other J-tubes 10 while simultaneously decreasing the pressure in the other J- tube_ This operation has already been explained with reference to figure l. As the height of the cylinder 32 is less than seven metres above the height of the pumping chambers 15, the required suction is produced alternatively in the pumping chambers without drawing a vacuum in the J-tubes.

The pump shown in figure 3 has many parts corresponding to those already described with reference to earlier figures and they have been denoted with the same reference numerals and will not be again described.

Unclean water shown at 43 is pumped upwardly in alternation through two hoses 50. These lead respectively into two one-way valve assemblies 51 each containing two one-way valves 16, 17 which open and close in alternation with fluctuation of water pressure inside the chamber 15 of the valve assembly.

The pump is operated by a piston-and-cylinder unit 54 containing a piston 7 which is reciprocated horizontally in the cylinder 8 by a rod 6 passing through a gland 47. The piston carries oppositely- irected leather bucket seals 42 to make the piston double-acting.

At each end of the piston chamber 8 a pair of venting tubes 44 lead upwardly through a valve 45 to a reservoir

46 of clean water. The valve 45 is normally closed but can be opened to allow air which collects in the upper ends of the pipes 44 over a period of time, to be vented to the atmosphere. Also clean water from the reservoir 46 can be forced into the opposite end-portions of the cylinder 8 when desired and after the valve 45 has been opened.

Pipes 55 extend downwards from opposite end of the cylinder 8 and terminate in the chambers 15 of respective assemblies 51. The slope of the pipes 55 is such that sediment and particulated matter precipitates downwardly through the water in the pipes when the pump is not in use.

The cylinder 8 and the upper end-portions of the pipes 55 are at all times filled with clean water so that there is no risk of solid matter entering the cylinder 8 and spoiling the seal of the piston within it. The lower end-portions of the pipes 55 contain unclean water to be pumped and the vertical lengths of the pipes 55 is such that throughout the stroke of the piston 7, an interface 30 formed between the clean and unclean columns of water in the pipes remains in their vertical portions so that clean water is not lost from the system and unclean water does not enter the cylinder 8.

Claims

CLAIMS :

1. A pump, comprising a pump chamber incorporating a uni-directional valve arrangement enabling flow of a pumped fluid into and out of the pump chamber in one direction, a conduit having one end opening into the pump chamber and another end connected to a drive means arranged to impart a reciprocating action to an auxiliary fluid within the conduit, the arrangement being such that, in operation, reciprocating action of the auxiliary fluid in the conduit causes pumped fluid to flow through the pump chamber in the one direction.

2. A pump in accordance with claim 1, wherein the valve arrangement comprises an inlet valve for allowing pumped fluid to be drawn into the pump chamber and an outlet valve for allowing pumped fluid to be ejected from the pump chamber, the arrangement being such that reciprocating action of the auxiliary fluid in the conduit provides a suction force when reciprocation is occurring in one direction to cause pump fluid to be drawn through the inlet valve into the chamber and a pushing force when reciprocation is occurring in the other direction to cause fluid in the chamber to be ejected therefrom through the outlet valve.

3. A pump in accordance with claims 1 or 2, the arrangement being such that, in operation, a fluid/fluid interface is formed within the conduit between the pumped fluid and the auxiliary fluid, the fluid/fluid interface being reciprocated in response to the reciprocating action imparted by the drive means, the reciprocation of the interface occurring entirely within the conduit.

4. A pump in accordance with claim 3, wherein one end portion of the conduit is arranged in operation to be in a substantially upright attitude, and wherein the drive means is arranged such that reciprocation of the fluid/fluid interface occurs entirely within - the substantially upright end portion of the conduit.

5. A pump in accordance with any preceding claim, wherein the conduit is a J-tube, the shorter limb of the J opening into the pump chamber and the longer limb being connected to the drive means.

6. A pump in accordance with any of claims 1 to 4, the conduit being arranged to be substantially vertically positioned in operation, the end of the conduit connected to the pump chamber sloping downwards such that particulate matter may precipitate out from the conduit during periods that the pump is not in use.

7. A pump in accordance with any preceding claim, the pump chamber being adapted to be placed within a well and being connected via a further conduit to the surface of the well to enable pumped fluid to be pumped from the well on operation of the drive means.

8. A pump in accordance with claim 7, wherein the drive means comprises a primary drive means and at least one power transmission device, the at least one power transmission device being adapted to be placed within the well and being arranged to transmit drive power from the primary drive means to the auxiliary fluid in the conduit to ensure that sufficient pumping force is transmitted to maintain the flow of pumped fluid through the chamber.

9. A pump in accordance with claim 8, wherein the primary drive means comprises a piston arranged to reciprocate within the cylinder to act on hydraulic liquid within the cylinder and a tube connecting the cylinder to the power transmission device, and the power transmission device comprises a further piston and cylinder arrangement, the piston being arranged to reciprocate in response to the action of the hydraulic fluid, the piston of the power transmission device transmitting its reciprocating action to the auxiliary fluid in the conduit.

10. A pump in accordance with any preceding claim, further comprising a damping means connected to the chamber and arranged to damp the flow of pumped fluid from the chamber, whereby to provide a more continuous flow of fluid from the pump.

11. A pump in accordance with claim 10, the damping means comprising a damping chamber connected to the pump chamber by a connecting conduit, a deformable membrane in the damping chamber sealing off a portion of the volume of the further chamber containing a gas, the arrangement being such that, in operation, as pumped fluid is pumped from the pump chamber the volume of gas in the further chamber is alternately compressed and expanded by action of pumped fluid from the chamber, whereby to provide a damping function.

12. A pump in accordance with any preceding claim, wherein a venting means is provided in communication with the other end of the conduit to enable unwanted gases to be vented from the auxiliary fluid.

13. A pump in accordance with any preceding claim, wherein a reservoir is provided for containing auxiliary fluid and means communicating with the other end of the conduit are provided to enable auxiliary fluid lost from the conduit to be replaced by auxiliary fluid from the reservoir.

14. A pump in accordance with any preceding claim, comprising at least one further pump chamber incorporating a uni-directional valve mechanism allowing pumped fluid flow into and out of the further pump chamber in one direction, a second conduit being connected to the further pump chamber having one end opening into the chamber and another end connected to a drive means arranged to impart a reciprocating action to an auxiliary fluid in the second conduit, the reciprocating action of the auxiliary fluid in the second conduit causing pumped fluid to flow through the further pump chamber in the one direction.

15. A pump in accordance with claim 14, wherein the conduit of the pump chamber and the second conduit of the further pump chamber are respectively connected to a drive means comprising a double acting piston arrangement, such that reciprocation of the piston is arranged to cause alternate phase reciprocation of the respective auxiliary fluids of the conduit and second conduit such that pumped fluid is alternately pumped through the pump chamber and the further pump chamber.

16. A pump in accordance with any preceding claim, wherein the pump is arranged such that the pumped fluid and auxiliary fluid are both liquids.

17. A pump in accordance with claim 16, wherein the pump is arranged such that the pumped fluid is water which may contain particulate and other unclean matter and the auxiliary fluid is water which is substantially free of particulate and other unclean matter.

18. A pump in accordance with claim 16, wherein the pump is arranged such that the pumped liquid is water which may contain particulate matter and other unclean matter and the auxiliary fluid is a liquid immiscible with oil.

19. A method of pumping fluid from a well along a first conduit incorporating a valve mechanism allowing flow of pumped fluid in one direction along the first conduit and having a second conduit with one end opening as a branch inlet into the first conduit, comprising the steps of providing an auxiliary fluid in the second conduit such that an interface is formed between the auxiliary fluid and the pumped fluid from the first conduit and reciprocating the interface within the second conduit to cause fluid to be pumped along the first conduit by virtue of the reciprocating action.

20. A method in accordance with claim 19, wherein the auxiliary fluid is water which may contain particulate matter and other unclean elements and the pumped fluid is water.

21. A method in accordance with claim 19, wherein the auxiliary fluid is a liquid immiscible with water and the pumped fluid is water which may contain particulate matter and other unclean elements.