WO1992012346A1

WO1992012346A1 - Pumps

Info

Publication number: WO1992012346A1
Application number: PCT/AU1992/000010
Authority: WO
Inventors: Keith Richard Draper
Original assignee: Mondesh Limited
Priority date: 1991-01-10
Filing date: 1992-01-10
Publication date: 1992-07-23

Abstract

A pump (40) having longitudinal hollow member (42) with a non-return valve (46) at its inlet end (44) and a plurality of serially connected spaced apart pistons (68), said pistons (68) allowing flow of fluid past or through said pistons (68) on the downward stroke but preventing or substantially preventing such flow on the upward stroke.

Description

PU PS

The present invention relates to pumps and relates particularly, although not exclusively, to low pressure pumps for pumping water.

It is an object of the present invention to provide a pump that is simple to use and manufacture.

A further object of the invention is to provide a pump that can be manufactured at low cost and comprises very few parts.

With these objects in view the present invention provides a pump having a longitudinal hollow member with a non-return valve at its inlet end, a plurality of serially connected spaced apart pistons, said pistons allowing flow of fluid past or through said pistons on the downward stroke but preventing or substantially preventing such flow on the upward stroke.

In order that the invention may be clearly understood and readily put into practical effect, preferred non-limitative embodiments of a pump made in accordance with the invention will now be described with reference to the accompanying drawings, in which:

Fig. 1 is a side view of a pump made in accordance with the invention;

Fig. 2 is a longitudinal cross-sectional view of the pump shown in Fig.

1; Fig. 3 is a cross-sectional view of a second type of piston that may be used in the pump of Fig. 1;

Fig. 4 is a cross-sectional view of a third type of piston that may be used in the pump of Fig. 1; and

Fig. 5 is a cross-sectional view of a fourth type of piston that may be used in the pump of Fig. 1;

Fig. 6 is a cross-sectional view of a fourth type of piston that may be used in the pump of Fig. I; and

Fig. 7 is a similar view to that of Fig. 2 showing a second embodiment of a pump made in accordance with the invention. In the embodiment shown in Figs. 1 and 2 there is a pump 40 including a pipe 42 which is preferably formed of a plastics material. Pipe 42 can be flexible to allow pipe 42 to be wound off a reel (not shown) or can be solid. Pipe 42 could also be made of metal or other material if required. Pipe 42 is closed at its lower end 44 by a non-return valve 46. The valve 46 comprises a ball 48 seated on a valve seat 50 to cover inlet aperture 52. Valve seat 50 is forced into the lower end 44 of pipe 42 and secured by a clamping ring 54.

The upper end 56 of pipe 42 is sealed by an apertured gland 58 secured by clamping ring 60. A take off tee 62 is clamped to pipe 42 and opens into aperture 65 in pipe 42 to allow fluid to exit the pump. A pipe 66 is inserted in take off tee 62, if required, to extend the outlet length of the pump. Inside pipe 42 is a bendable cable 64 with a plurality of pistons 68 secured thereto. A distance of 3000mm in use, has been found to be a workable separation between pistons 68. Cable 64 can be replaced by a rod or plurality of rods, if it is not required to have a flexible pipe 42. Each piston 68 forms a cup-shaped member with a main body 70 and a resilient upwardly directed sealing lip 72. The pistons are preferably formed of a rubber or plastics material. Cable 64 has a sleeve 74 crimped thereon which slides through gland 58.

In use, cable 64 is pulled up and down as indicated by arrows 76. On the up stroke the pressure of the fluid in pipe 42 forces the sealing lips 72 against the inner wall of pipe 42. Simultaneously the non-return valve 46 opens to allow entry of fluid into the pump. Fluid is then lifted upwardly to pass out through pipe 66 by movement of the upper most piston. On the down stroke the sealing lips 72 collapse inwardly allowing fluid to pass through the gap formed by the sealing lips 72 and the inner wall of pipe 42. The passage of fluid can create a turbulence inside piston 68 to prevent deposition of solids therein. Non-return valve 46 will be forced closed on the down stroke. The continuous up and down movement of cable 64 will thus result in the pumping action. The pump is suited for pumping both gas and liquids. If required, the end 78 can have a weight (not shown) attached thereto or can be resilientiy biased.

Pistons 72 can vary in shape and operation as shown in the alternatives depicted in Figs. 3 to 6.

In Fig. 3 piston 68 has flexible lips 80 which are flatter than those shown in Fig. 2. Main body 70 is substantially smaller in size and has a flange 82 on which lips 80 will rest on the down stroke.

In Fig. 4 apertures 84 can be located in flange 82 which will act as a non-return valve on the down stroke. In this manner non-return valve 46 could be omitted.

In Fig. 5 piston 68 is in two parts comprising a conical main piston 86 and conical valve member 92. Valve member 92 has a plurality of flexible fingers similar to a shuttlecock and seats neatly inside main piston 86. The fingers are gathered together on a collar 90. Conical main piston 86 has a set of apertures 88 which are overlapped by the fingers to provide a valve structure. On the downstroke the fingers will be forced inwardly allowing fluid to pass through apertures 88 to increase the throughput of the pump. The apertures provide a turbulence for the fluid which prevents deposition of solids within piston 68. A self-flushing action is provided by this construction. Fig. 6 shows a variation of the piston shown in Fig. 3. Piston 68 has lips 80A which do not contact the inner wall of pipe 42. The lips 80A are stiffer and will not collapse inwardly on the downward stroke. As the area of the annular gap 94 between pipe 42 and lips 80A is smaller than the cross-sectional area of pipe 42 pumping will still occur without the friction losses of the piston shown in Fig. 3. The leakage through the annular gap 94 is small compared with the lift produced by piston 68. The pistons shown in Figs. 4 and 5 could also be modified to avoid contact of the pistons with the inner wall of pipe 42.

Fig. 7 shows a modification of the pump shown in Fig. 2. The same reference numerals have been used for corresponding components between the embodiments depicted. The modification comprises extending the upper end 56 of pipe 42 to provide an extension 96 for a pump head. A piston 68A similar to pistons 68 can move in extension 96. Piston 68A is of stiffer material than pistons 68 and does not lift off the inside wall of extension 96. A non-return valve 98 is provided in pipe 66 to control fluid flow. In use, the pump operates in the same manner as previously described.

On the up stroke fluid will enter extension 96 and non-return valve 98 will remain closed. On the down stroke fluid will be forced out extension 96 through non¬ return valve 98 by piston 68A.

As can be seen from the above embodiments the invention provides a simple low cost pump. The pump is easy to manufacture and provides a cheap alternative, especially for third world countries.

It will be understood that any modifications may be made in details of design and/or construction without departing from the ambit of the invention, the nature of which is to be ascertained from the foregoing description and appended claims.

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Claims

The claims defining the invention are as follows:-

1. A pump having a longitudinal hollow member with a non-return valve at its inlet end, a plurality of serially connected spaced apart pistons, said pistons allowing flow of fluid past or through said pistons on the downward stroke but preventing or substantially preventing such flow on the upward stroke.

2. The pump of claim 1, wherein each of said pistons are secured to a cable passing therethrough.

3. The pump of claim 2, wherein each piston includes a main body for attachment to said cable and a resilient sealing lip on said main body for sliding along the inner wall of said longitudinal hollow member.

4. The pump of claim 3, wherein each sealing lip extends from said main body in a direction away from said inlet end.

5. The pump of claim 4, wherein said sealing lip and main body form a cup-shaped member.

6. The pump of claim 4, wherein said piston has a flange below said resilient lip on which said resilient lip rests on the downward stroke of said pump.

7. The pump of claim 6, wherein said flange is apertured.

8. The pump of claim 4, wherein said piston comprises a pair of stacked conical members, the outer conical member having a plurality of apertures and the inner conical member having a plurality of fingers which co-operate to overlay said apertures to form a valve.

9. The pump of claim 1, wherein each of said pistons are secured to a rod or a plurality of rods passing therethrough.

10. The pump of any one of the preceding claims, wherein a pump outlet is provided in the side wall of said longitudinal hollow member.

11. The pump of claim 10, wherein said longitudinal hollow member extends beyond said pump outlet and a piston, serially connected to saici spaced apart pistons, is located in said extension.

12. The pump of claim 11, wherein a non-return valve is provided in said pump outlet.

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