GB2150224A - Fluid-operated diaphragm pump - Google Patents

Abstract

A fluid-operated diaphragm pump having a flexible tube diaphragm 10 contained within a tubular casing 12, the diaphragm being sealed at each end with respect to the casing so as to form a central chamber 14 surrounded by an annular chamber 16, there being check valves 22, 24 opening in the same direction at the opposite ends of one of said chambers so that pulsations of pressure in the other chamber can produce a pumping action in said one of said chambers. So that the pump can be used for down-the-hole pumping, a bore 40 in a closure member 36 at an outlet end of the pump communicates with the annular chamber surrounding the flexible diaphragm without increasing the overall width dimensions of the pump. <IMAGE>

Description

SPECIFICATION Fluid-operated diaphragm pump The invention relates to fluid-operated diaphragm pumps of the kind having a flexible tube diaphragm contained within a casing, the diaphragm being sealed at each end with respect to the casing so as to form a central chamber surrounded by an annular chamber, one of the said chambers constituting a pumping chamber and the other constituting a pulsation chamber. The ends ofthe pumping chamber are provided with respective check valves which open in the same direction and operate automatically as the pressure of a working fluid in the pulsation chamber is caused to pulsate under the action of a remote power unit.

Fluid-operated diaphragm pumps ofthe kind referred to are used for pumping various liquids and slurries throughout industry. It is now desired to use such pumps down boreholes and the present invention aims to make this possible.

According to the invention, there is provided a fluid-operated diaphragm pump having a flexible tube diaphragm contained within a tubular casing, the diaphragm being sealed at each end with respect to the casing so as to form a central chamber surrounded by an annular chamber, one of said chambers constituting a pumping chamber and the other constituting a pulsating chamber, and the ends of the pumping chamber being provided with respective check valves which open in the same direction, in which a bore in a closure member at an outlet end of the pump communicates with the annular chamber, the arrangement being such that a high pressure hose can be connected to the annular chamber of the pump without increasing the overall width dimensions of the pump.The working fluid or the liquid or slurry as the case may be, in the high pressure hose will preferably communicate with the annular chamber by way of a cavity in the closure member and a series of holes which extend through a flange portion of a spacer member. The pump may be operated directly by the pulsations of pressure fluid transmitted to the pump from ground level through the high pressure hose.

Alternatively, the pump may be powered buy a slave cylinder itself powered by high pressure fluid transmitted to it from ground level.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure lisa longitudinal section through a fluidoperated diaphragm pump embodying the invention, Figures 2,3,4 and 5 are diagrammatic illustrations of various means which can be employed for powering the pump, Figure 6 is a view similar to Figure 1 and illustrating a possible modification of the pump, and Figures 7 to 9 are sectional views on the lines 7-7, & and 9--9 respectively in Figure 6.

Referring nowto Figure 1 ofthedrawings,the fluid-operated diaphragm pump there illustrated includes a flexible tube diaphragm 10 contained within a tubular casing 12, the diaphragm being sealed at each end with respect to the casing so as to form a central pumping chamber 14 surrounded by an annular pulsation chamber 16.

As shown, respective closure assemblies at the opposite ends of the tubular casing include spigot portions 18 and 19 on which the opposite ends of the flexible tube diaphragm are clamped by respective hose clips 20. The respective closure assemblies also include check valves 22 and 24 which open in the same direction from their respective seatings. The check valve 22 closes against a seating formed at the end of a tubular spigot 26 formed on a closure member 28 of the tubular casing. The tubular spigot 26 is surrounded by a spacer member 30 within which the check valve 22 is held captive and on which the spigot portion 18 is formed.The check valve 22 is located at the inlet end of the pump, that is to say at the end at which the liquid orslurryto be pumped can enterthe pumping chamber through a suction passage 32 in the closure member 28 in response to a reduced pressure brought about in the pulsation chamber 16.

The check valve 24 on the other hand closes against a seating which is formed within the spigot portion 19, the latter being integral with a spacer member 34 a flange portion of which is located between the tubular casing 12 and a closure member 36. The check valve 24 is located at what is the outlet end of the pump, that is to say at the end at which the liquid or slurry to be pumped can be forced from the pumping chamber through a discharge passage 38 in the closure member 36 in response to a high pressure brought about in the pulsation chamber 16.

Ascrewthreaded bore 40 in the closure member 36 communicates with the annular pulsation chamber 16 by way of a cavity 42 and a series of holes 44 which extend through a flange portion of the spacer member 34.

The arrangement is such that the pump can be lowered down a borehole from which water or slurry is to be pumped, suspended by the length of high pressure hose (shown in chain-dotted lines in the drawing) through which the water or slurry is to be pumped and also by a length of high pressure hose (also shown in chain-dotted lines) through which the working fluid is to be pumped to and from the annular pulsation chamber 16. A power unit for imparting pulsations of variable magnitude to the working fluid will be located at ground level.

It will be understood that a fluid-operated diaphragm pump embodying the invention may be manufactured in any suitable size but that its compact cylindrical shape makes it ideal for "downthe-hole" pumping. This is because the high pressure hose through which pulsations of pressure can be transmitted to the working fluid in the annular pulsation chamber is connected to the pump in a manner which does not increase its overall width dimensions. The pump may however be employed in other situations, for example in chemical plant. Various modifications may be made and it will be understood that the various component parts of the pump may be made from materials most suitable for use with the kinds of liquids or slurries which are to be pumped.

The pump illustrated in Figure 1 may be operated directly by the pulsations of pressure fluid transmitted to the pump from ground level through the high pressure hose shown in chain-dotted lines connected into the screwthreaded bore 40.

However, the pump may alternatively be powered by a slave cylinder itself powered by high pressure fluid transmitted through said high pressure hose.

For example, in Figure 2 there is illustrated an arrangement in which a slave cylinder generally indicated 46 contains a free piston 48 acted on at its underside by a spring 50. A space above the piston 48 communicates by way of a high pressure hose 52 with a hydraulic cylinder 54 at ground level, the latter containing a driving piston 56 the piston rod 58 of which is provided with or connected to a toothed rack element 60. The toothed rack element is engaged by a toothed quadrant 62 drivably connected to a hand lever 64. The arrangement is such that by the operation of the hand lever pulsations of pressure can be transmitted to the slave cylinder through the high pressure hose 52, the pulsations being transmitted from the slave cylinder to the pump through the series of holes 44 in the flange portion of the spacer member 34.The liquid or slurry forced through the pump in response to the pulsations of pressure brought about in the pulsation chamber is shown being raised through a hose 66 and being discharged into a settling tank 68.

In Figure 3 there is illustrated an arrangement very similar to that just described except that the hand lever 64 is drivably connected to the piston 56 by means of a crank and connecting rod mechanism generally indicated 70.

In Figure 4there is illustrated a modification which could be made to either one of the operating arrangements illustrated in Figures 2 and 3, this being a dual slave cylinder arrangement in which a main slave piston 72, acted upon by pulsations of pressure transmitted to it through the high pressure hose 52 from ground level, is directly connected to a smaller piston 74 which is acted upon by the spring 50 and which transmits the pulsations of pressure to the pump.

In Figure 5 there is illustrated a further possible modification of the last described dual slave cylinder arrangement. In this case the coupled pistons of the slave cylinder are not acted upon by a spring but the spaces above and below the main slave piston 72 communicate with respective hydraulic cylinders 54 and 55 at ground level, said cylinders containing respective driving pistons 56 and 57. The driving pistons are drivably connected, in out-of-phase relation, with a double crank and connecting rod mechanism, generally indicated 76, capable of being turned by a handwheel 78. It will thus be seen that the coupled pistons of the slave cylinder are in this case positively driven in each direction.

It will of course be understood that any of the illustrated means for powering the pump may be driven by an electric motor, for example, or by other power driven means instead of by a hand lever or handwheel.

Various modifications may be made to the diaphragm pump itself. For example, the pumping chamber need not necessarily be surrounded by the pulsation chamber. In Figures 6to 9 there is illustrated an arrangement very similar two that previously described except that in this case the central chamber is the pulsation chamber and the chamber surrounding it is the pumping chamber.

Consequently, the valving to the respective chambers is rather different from that in the previously described pump. For example, the check valve 22 which is located at the inlet end of the pump opens to allow the liquid or slurry to be pumped to enter the pumping chamber th rough a suction passage 32 (in this case formed in an inlet strainer member 33) but since the pumping chamber is in this case the annular chamber 16 the closure member 28 of the tubular casing does not have a central through bore but a series of ports 35 which open into said annular chamber. The check valve 22 is located, as shown, between the closure member 28 and a flange portion of the inlet strainer member.

The check valve 24, which opens in the same direction as the check valve 22 is not located at the upper end of the central chamber but is located in a pipe arrangement 37 which is connected to the closure member 36 of the tubular casing and communicates with the annular chamber. The central chamber 14, which in this case forms the pulsation chamber, is not provided with check valves; as shown, its lower end is blanked off, the spigot portion 18 of the closure member 28 being provided with a blind bore. The working fluid to be pumped to and from the central pulsation chamber communicates with the latterthrough a pipe arrangement 39, which itself is connected to a length of high pressure hose shown in chain-dotted lines, from ground level, either directly or via a slave cylinder as previously described.

A further difference between this form of pump and that described with reference to Figure 1 is that this modified pump is provided with a cage member 41 surrounding the flexible tube diaphragm. As shown, this provides a series of annular rings spaced apart along the length of the diaphragm and acting to limit the extent by which the diaphragm can expand when subjected to internal pressure by the working fluid.

Claims (5)

1. Afluid-operated diaphragm pump having a flexible tube diaphragm contained within a tubular casing, the diaphragm being sealed at each end with respect to the casing so as to form a central chamber surrounded by an annular chamber one of said chambers constituting a pumping chamber and the other constituting a pulsation chamber, and the ends of the pumping chamber being provided with respective check valves which open in the same direction, in which a bore in a closure member at an outlet end of the pump communicates with the annular chamber, the arrangement being such that a high pressure hose can be connected to the annular chamber of the pump without increasing the overall width dimensions of the pump.

2. A fluid-operated diaphragm pump according to claim 1, in which the working fluid or the liquid or slurry, as the case may be, in the high pressure hose can communicate with the annular pulsation chamber by way of a cavity in the closure member and a series of holes which extend through a flange portion of a spacer member.

3. A fluid-operated diaphragm pump according to either one of the preceding claims, in which the pump is operated directly by the pulsations of pressure fluid transmitted to the pump from ground level through the high pressure hose.

4. Afluid-operated diaphragm pump according to either one of claims 1 and 2, in which the pump is powered by a slave cylinder itself powered by high pressure fluid transmitted to it from ground level.

5. A fluid-operated diaphragm pump constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.