GB2181188A - Water pumps - Google Patents

Abstract

A water pump comprises a chamber (1) with an inlet (12) for coupling to a compressed air supply. A flap valve (6) allows water to enter the chamber (1) when the pressure thereof externally of the chamber (1) exceeds the air pressure applied at inlet (12). Increasing the air pressure applied at the inlet (12) can then force water from the chamber (1) up an outlet pipe (10). A non-return valve (11) is provided in the outlet pipe (10) to prevent the reverse flow of water when the air pressure in the chamber (1) is again reduced. <IMAGE>

Description

SPECIFICATION Improvements in water pumps This invention relates two improvements in water pumps. Specifically, the invention relates to a direct displacement air operated pump designed for agricultural and domesticwatersupply purposes in remote areas and in underdeveloped countries.

Although reference may be madethroughoutthis specification to the invention as a "water" pump, it is to be understood that the pump is not limited to this specificapplication and is suitable for use in pumping a wide range of different liquids.

In the past water has commonly been pumped from wells or bores by a mechanical pump submer gedbelowthelevel ofthewatertable inthewell and driven bya mechanical linkagefrom the surface above the well. Such water pumps are commonly powered by windmills erected on a tower above the well and are provided with a mechanical linkage to drive a reciprocating rod which extends down the well to the submerged water pump to provide power to the pump. These windmill systems have the disadvantagethatthey are expensive to manufacture and install dueto the complex nature ofthe mechanical equipment and to the difficulty in inserting the pump and drive rod intothewell.Furthermorethey are expensive to maintain, asthe pump must be re- moved from the well for periodic maintenance and/ or replacement of parts which is an expensive and time-consuming process.

It is a further disadvantage of the present wind powered pumps that due to the nature of the direct mechanical drivethewindmill must be located directly above the well or bore, which is frequently not the most advantageous positionforthewindmillto catch the prevailing winds. It is commonforthewell or bore to be located in a valley which is sheltered fromthewind, but it is desirableto place thewindmill on the top ofhillssurrounding the valley ratherthan in the valley itself.

It is an object of the present invention to provide a water pump which will obviate or minimisethefore- going disadvantages in a simple yet effective manner or which will at least provide the public with a useful choice.

It is a further object of the present invention to provide a pump having a minimum of moving partsto reduce to a negligible degreethewearfactorin- herent in all submerged pumping situations.

In achieving these objectives, it has been found that optimum results are achieved if the materials used in the construction ofthe pump are of a compatible nature and are selected for durability, antierosion qualities and anti-abrasion qualities. These materials are readilysourced in all industrial countries and include gun metal steel, high pressure P.V.C., appropriate stainless steels and high density polyurethane.

In accordance with one embodiment ofthe present invention there is provided a liquid pump having: a chamber adapted to be submerged below the level of liquid to be pumped; a non-return liquid inlet valve in the iower part of said chambercommunicating with the exteriorthereof and arranged to allowthe liquid to be pumped to passthrerethrough into said chamber but which prevents said liquid from passing therethrough out of said chamber; a non-return liquid outlet valve communicating between the lower part of said chamber and a water supply outlet, said outlet valve being arranged to allowthe liquid to be pumped to pass therethrough out of said chamber into a water supply outlet but which prevents there verse flow of liquid therethrough; and compressed air supply means in the upper part of the chamber operabletoeithersupplycompressed airtothesaid chamberortoventairfrom said chamber.

The arrangement of the pump provides for only two moving parts, these being, in one embodiment, afoot valve at the base of the pump chamber and a vertically oriented non-return valve at the top of the pumpto preventwaterfrom returning to the chamber. Although these parts move, it is anticipated that they will have an extremely long life, giving the advantage of simplicity and exceptional durability.

Preferably, said chamber comprises a cylindrical chamber having a vertical axis with said compressed air supply means located at the upper end ofthe cylinder.

Preferably, said non-return liquid outlet valve is located at the upper end of a pipe extending downwardly into said chamberfrom the upper end thereof.

Preferably, said non-return inlet valve comprises a high density polyurethanefootvalve.

In one preferred embodiment the cylindercomprises a high pressure P.V.C. tube capped by a gun metal head incorporating water delivery supply means and compressed airsupplyand venting means, and sealed at the lower end thereof by a gun metal base having provided therein appropriate orifices to co-operate with said foot valve to form a nonreturn liquid inlet valve.

In a further aspect the invention comprises a pumping system adapted to pump waterfrom a well, said pumping system comprising a water pump as described located in said well belowthewatertable level, an aircompressor connected to the air inletvalve by an air supply conduit, and a water supply conduit connected to said water supply outlet.

Preferably said air compressor is driven by a windmill.

Alternatively, said air compressor is driven by an engine or motor.

Preferably said water supply conduit is connected between said water supply outlet and a storage tank located on the surface above said well.

Preferably said air supply conduit and said water supply conduit both comprise flexible hoses extending down said well to said water pump.

Notwithstanding anyotherformsthatmayfall within its scope, one preferred form ofthe invention will now be described by way of example only, with reference to the accompanying drawing in which: Figure lisa cut-away perspective view of a water pump according to an embodiment of the invention.

In a preferred form of the invention, a water pump is constructed as follows, with reference to figure 1.

The pump comprises a chamber 1 which is preferably formed to the configuration of a vertical cylinder and may conveniently be formed from a length of pipe 2 having a closed upper end 3 and a lower end 4, with inlet parts 7.

Compressed air may be admitted to the chamber throughthecompressedairsupplymeans l2forcing the water level downwardly in the chamber and causing the flap valve 6to close downwardly againstthe lower end 4which acts as a valve seat, and the outlet valve 11 to open. Water is forced by the air pressure upthe pipe 10through the outletvalve 11 afterwhich it passes along an outlet hose 9 to the point of delivery.Once the water level has been forced down in the chamberbythe emission ofcompressedairfora predetermined period oftime, the compressed air supply is shut off and water pressure then forces the water inlet valves open and air within the chamber is vented up through said airsupply means 12 by app ropriatevalving arrangements remote from the pump. After a predetermined period oftime a further supply of compressed air is introduced to the chamber, the water level is forced down, the inlet valve closes and the cycle is repeated. Water in the outlet pipe is prevented from draining back into the chamber by the non-return outletvalve 11.

Preferably,the pipe 10 is arranged centrally in the chamber 1 ,and a circularflapvalve 6 of high density polyurethane is provided. The circularflap valve 6 is freely moveable up and down between the stop 8 and the lower end 4, guided bythetie rod 5. The lower end 4 having orifices 7, acts as an inlet valve seat to theflapvalve 6.

The water pump according to the invention may be used in a number of different applications such as for pumping water from rivers or dams or may alternati vely be usedfor pumping a widevarietyof liquids in a widely differing number of applications.

In the preferred application of the water pump, the pump is submerged in a well or bore so that the pump is located below the water table. The pump is driven by compressed air passed through a flexible air hose extending down the well from an aircompressor on the surface which is preferably driven by a windmill. Because of the flexible nature of the air supply hose, the windmill may be located in a desired position to catch the prevailing winds which is not necessarily directly abovethe well head. The out letfrom the water pump is connected to a further flexible hose extending up the well to the point of delivery such as a water storage tank or dam.

In the above described embodiment, the valve timing means are preferably provided in the vicinity of the well head. In this pumping system, it is possible to provide in an economic manner an extremely ef ficientand reliable water pumping system which has particular applications in agricultural situations and in the pumping of water in underdeveloped countries where motorised power is seldom available. The system is also extremely flexible in that in agricultural situations when there is insufficient wind to drive the water pump, the compressed air supply hose may be connected to an engine or motor driven compressorso thatwater may still be pumped from the well.

The volume of air in the compressed airsupplyline acts as a compressed air reservoir to smooth out the air demand between the intermittent operation of the pump andthe continuous supplyfrom the aircom- pressor. If necessary the amount of compressed air held in reserve may be increased by providing a pres sure tank in the line preferably located at or adjacent the windmill.

Where it is desired to pump water from welis having a depth greaterthan 300 ft., it is possible to gang water pumps in series at intervals down the well so that the lower-most pump raises waterto the level of the next pump which then raises waterfurther up the well to the surface orto the next successive pump.

Claims (11)

1. A liquid pump having; a chamber adapted to be submerged belowthe level of liquid to be pumped; a non-return liquid inlet valve in the lower part of said chamber communicating with the ex teriorthereofand arranged to allowthe liquid to be pumped to passtherethrough into said chamber but which prevents said liquid from passing therethrough out of said chamber; a non-return liquid outlet valve communicating between the lower part of said chamber and a water supply outlet, said outlet valve being arranged to allow the liquid to be pumped to pass therethrough out of said chamber into a water supply outlet but which prevents there- verse flow of liquid therethrough; and compressed airsupply means in the upper partofthe chamber operableto eithersupplycompressed airto the said chamberortoventairfromsaidchamber.

2. A pump as claimed in claim 1 wherein there is provided not more than two moving parts namely said non-return inlet valve and said non-return outlet valve.

3. A pump as claimed in claim 2wherein said cham ber com prises a closed cyl inder having a su b- stantiallyvertical axis provided with said com pressed airsupplymeans atthe upperend of said cylinder.

4. A pump as claimed in claim 3 wherein said non-return outlet valve is located at the upper end of a liquid supply pipe extending downwardly into said chamberfrom the upper end thereof.

5. Apumpasclaimed in claim 3 wherein said non-return inlet valve comprises a flap valve and valve seat.

6. A pump as claimed in claim 1 wherein said compressed air supply means is operable to intro ducecompressedairintosaidchamberfora pred- etermined period oftime, after which supply is shut off by appropriate means remote from the pump, following which the said supply means vents the chamber in the reverse direction by appropriate valving arrangements also remote from the pump, thus allowing the chamberto flood and the pumping cycle to recommence.

7. A pump as claimed in claim 6 in which said supply means vents said chamberfor a pred- etermined period oftime.

8. A pump as claimed in claim 6 in which valve and timing means to control the supply of com pressed air and the venting thereof are located ata point remotefrom the liquid two be pumped.

9. A pumping system adapted to pump water from a well, said pumping system comprising a water pump as claimed in any one of the preceding claims located in said well below water level, an air compressor connected to said compressed air supply means byaflexible airsupplyconduitvia appropriate valving and timing arrangements located remote from the pump, and a flexible water supply conduit connected to said water supply outlet.

10. A pumping system as claimed in claim 9 wherein said air compressor is driven byawindmill or engine.

11. A liquid pump substantially as described herein with reference to the accompanying drawing.