GB2257481A

GB2257481A - A diaphragm pump.

Info

Publication number: GB2257481A
Application number: GB9210004A
Authority: GB
Inventors: Steven West; Brian Blackmore
Original assignee: UNIHOLD GROUP Ltd
Current assignee: UNIHOLD GROUP Ltd
Priority date: 1991-07-08
Filing date: 1992-05-08
Publication date: 1993-01-13
Also published as: GB9210004D0

Abstract

A diaphragm pump (10) includes a pumping vessel (12) and a booster vessel (14). Both vessels have diaphragms (20, 26) connected to one another. The booster vessel (14) has at least one booster air chamber (22) for boosting the force exerted by the diaphragm (20) in the pumping vessel (12) during its pumping stroke. Compressed air is fed through an inlet (29) and connected by a shuttle valve (30) to an air chamber (18) of the pumping vessel (12) and simultaneously, via a pipe (50), to the air chamber (22) of the booster vessel (14), to effect the pumping stroke. During the return stroke the compressed air is connected to a return chamber (24) of the booster vessel (14). The working fluid is drawn into a pumping chamber (16) of the pumping vessel (12) via a one way valve (36) and exits via a second one way valve (38). The pump may incorporate two pumping vessels (62, 64 fig. 2). <IMAGE>

Description

A DIAPHRAGM PUMP This invention relates to a diaphragm pump.

According to the invention a diaphragm pump includes: at least one pumping vessel and at least one booster vessel; a pumping diaphragm in the pumping vessel and a booster diaphragm in. the booster vessel, the diaphragms dividing eacn vessel into two chambers, the chambers of the pumping vessel comprising a media chamber and an air chamber and at least one of the chambers of the booster vessel comprising a booster air chamber; and connecting means connecting the diaphragms together so that they can reciprocate in unison within the vessels; air in use of the pump being fed into the air chamber of the pumping vessel and into a booster air chamber of the booster vessel during the pumping stroke of the pumping diaphragm, so that the force exerted by the air on the booster diaphragm can be transmitted through the connecting means to the pumping diaphragm to boost the force exerted by the pumping diaphragm during its pumping stroke.

The booster vessel may contain an air chamber and a return chamber with the return chamber including valve means which allows air to flow out of the return chamber during the pumping stroke of the pump, and which allows air to flow into the return chamber to cause the suction stroke of the pump.

Alternatively, biassing means may be provided to cause the suction stroke of the pump. In such a case the return chamber may include a valve or a ermanent opening through which air can be vented during the pumping stroke of the pump.

The diameter of the booster diaphragm may be larger than the diaphragm of the pumping diaphragm to increase the booster force transmitted to the pumping diaphragm.

In one form of the invention the pump has two pumping vessels and a single booster vessel, with the diaphragm of the booster vessel dividing the booster vessel into two booster air chambers so that the booster air chambers can alternately boost the force exerted by the pumping diaphragms during their respective pumping strokes. Thus the return chamber of the booster vessel is an air chamber. Preferably the booster vessel is interposed between the two pumping vessels. In this arrangement the media chambers are preferably located at opposite ends of the pump so that the connecting means does not come into contact with the media to be pumped.

The invention will now be described by way of a non-limiting example with reference to the accompanying drawings in which: figure 1 is a diagrammalic cross-sectional view of a boosted single diaphragm pump; figure 2 is a diagrammatic cross-sectional view of a boosted double diaphragm pump; figure 3 is a diagrammatIc cross-sectional view of a boosted double diaphragm pump according to another embodiment of the invention with the diaphrams at one end of their stroke; and figure 4 is the same pump as shown in figure 3 but with the diaphragms at the other end of their stroke.

Referring firstly to figure 1 a boosted single diaphragm pump 10 includes a pumping vessel 12 and a booster vessel 14. The pumping vessel 12 is divided into a media chamber 16 and an air chamber 1 by a pumping diaphragm 20. Similarly, the booster vessel 14 is divided into an air chamber 22 and a return chamber 24 by a booster diaphragm 26.

The two diaphragms are connected together by connecting means in the form of a connecting rod 28.

Compressed air is fed to the pump through an inlet 29. A shuttle valve 30 switches the supply of the compressed air to the pump between inlet conduits 31 and 32 as the connecting rod 28 reciprocates.

The compressed air is fed from the shuttle valve 30 to the air chamber 18 via the conduit 32 and a one-way inlet valve 34. Similarly the compressed air is fed to the return chamber via the conduit 31 and a one-way inlet valve 35.

In addition to the one-way valves 34 and 35, the pump also has a one-way inlet valve 36 and one-way outlet valves 38,- 40, 42 and 43. The air chambers are connected together through one-way valves 46 and 48 by a pipe 50.

In use, media such as a slurry is pumped through the media chamber 16. During the pumping stroke compressed air flows into the air chamber 18 through the inlet valve 34, and into air chamber 22 through the pipe 50 while outlet valves 40 and 42 are closed. Thus compressed air flows into the two air chambers substantially simultaneously The compressed air forces both the diaphragms in the direction of arrows 54 and the slurry in the media chamber is forced out the outlet valve 38 during this pumping stroke. Once the pumping stroke has been cctpleted, the ;j'nuttle salve then feeds compressed air to the return chamber 24 while valve 43 is closed.Air is then tested from both the air chambers through outlet valves 40 and 42 during the return stroke as the diaphragms move in the direction of arrows 56.

The pumping and the suction strokes occur alternately. During the pumping stroke the force exerted by the compressed air on the booster diaphragm is transmitted through the connecting rod 28 to boost the force exerted by the pumping diaphragm on the slurry within the media chamber 16. During the return stroke the force exerted by the air in the return chamber on the booster diaphragm is transmitted through the connecting rod 28 to move the pumping diaphragm On its suction stroke.

The applicant has found that, for example, with a 3 bar air supply, the booster force provided by the booster chamber increases the pressure performance of the boosted single diaphragm pump by as much as one and a half times.

Referring now to figure 2, a boosted double diaphragm pump 60 includes pumping vessels 62 and 64, and a booster vessel 66. The pumping vessel 62 nas a media chamber 68 and an air chamber 70 separated by a diaphragm 72. Similarly the pumping vessel 64 has a media chamber 74 and an air chamber 76 separated by a diaphragm 78. The booster vessel 66 has two booster air chambers 80 and 82 separated by a diaphragm 84. The three diaphragms are connected to one another by a connecting rod 86.

The booster air chamber 30 communicates with air chamber 70 via a pipe 88. Similarly, the booster air chamber 82 communicates with air chamber 70 via a pipe 90.

The boosted double diaphragm pump 60 operates in much the same manner as the boosted single diaphragm pump. Air is however introduced into air chambers 80 and 70 substantially simultaneously and thereafter into air chambers 82 and 76 substantially simultaneously, whereafter the cycle is repeated. The media output from the boosted double diaphragm pump is substantially continuous and twice that of a boosted single diaphragm pump.

Referring now to figures 3 and 4 a boosted double diaphragm pump 92 includes pumping vessels 93 and 94, and a booster vessel 105. The pumping vessel 93 has a media chamber 95 separated from an air chamber 96 by a pumping diaphragm 97. Similarly, the pumping vessel 94 has a media chamber 98 separated from an air chamber 39 by a pumping diaphragm 100. The booster air chambers 101 and 102 are separated by a booster diaphragm 103. The three diaphragms are connected to one another by a connecting rod 104. Air chambers D9 and 101 are in communication with one another. Similarly air chambers 96 and 102 are in communication with one another.

The pump 92 operates in much the same manner as the pump 60 in that air is introduced into air chambers 99 and 101 simultaneously and thereafter into air chambers 96 and 102 simultaneously.

The connecting rod 104 of pump 92 does not come into contact with any of the slurry. Consequently the seals between adjacent air chambers of the respective vessels have air on both sides of them.

Whereas in pump 60, air and slurry are located on opposite sides of the seals which leads to increased wear and difficulty in sealing.

For the sake of clarity, the pumps shown in figures 2 to 4 do not include details of the inlet and outlets valves of the various chambers.

It will be appreciated that many modifications or variations of the invention are possible.

Claims

1. A diaphragm pump including: at least one pumping vessel and at least one booster vessel; a pumping diaphragm rn the pumping vessels and a booster diaphragm in the booster vessel the diaphragms dividing the vessels into two chambers, the chambers of the pumping vessel comprising a media chamber and an air chamber, and at least one of the chambers of the booster vessel comprising a booster air chamber; and connecting means connecting the diaphragms together so that they can reciprocate in unison within the vessels; air in use of the pump being fed into the air chamber of the pumping vessel and into a booster air chamber of the booster vessel during the pumping stroke of the pumping diaphragm so that the force exerted by the air on the booster diaphragm can be transmitted through the connecting means to the pumping diaphragm to boost the force exerted by the pumping diaphragm during its pumping stroke.

2. The diaphragm pump of claim 1 including two pumping vessels and a single booster vessel, with the diaphragm of the booster vessel dividing the booster vessel .nto two booster air chambers so that the booster air chambers can alternately boost the force exerted by the pumping diaphragms during their respective pumping strokes.

3. The diaphragm pump of claim 2 wherein the booster vessel is interposed between the two pumping vessels.

4. The diaphragm pump of claim 3 wherein the media chambers are located at opposite ends of the pump so that the connecting means does not come into contact with the media.

a. & diaphragm pump substantially as herein described or illustrated with reference to the accompanying drawings.