GB2079858A - Diaphragm pump - Google Patents

Abstract

A diaphragm pump (1) comprising a housing formed from two concave casings (2, 4) which abut one with the other about a common flat annular region, one of the casings incorporating a valved inlet (50) for admitting fluid to the pump and a valved outlet through which fluid can be expelled from the pump, each of the casings (2, 4) having a shoulder portion which extends radially over said annular region and is adapted and arranged to abut with the shoulder portion of the other casing (4, 2), a seal between the shoulder portions, and releasable clamping means (24) for releasably holding together the two casings (2, 4) about the seal thereby permitting rotational adjustment of one casing relative to the other about the axis of said annular region. <IMAGE>

Description

SPECIFICATION Diaphragm pump The present invention relates to a diaphragm pump.

Diaphragm pumps are used for a variety of pumping applications and hand-operated pumps for pumping water from the bottom of small boats and sailing dinghies are often of this type. Pumps made for use in boats and dinghies usually have their inlets and outlets located in positions which are fixed relative to the means for mounting the pump and to the lever which operates the pump.

This can be a great disadvantage since it can lead to difficulties in installing the pump particularly because of the lack of space in the holds of small boats.

The present invention provides a diaphragm pump of a type suited particularly for use as a bilge pump for mounting in areas of restricted access in which the disposition of the inlet and the outlet of the pump can be easily altered to a number of different positions and thereby facilitate the fixing of the pump in positions of limited access.

Accordingly, the present invention provides a diaphragm pump comprising a housing formed from two concave casings which abut one with the other about a common flat annular region, one of the casings incorporating an inlet for admitting fluid to the pump and an outlet through which fluid can be expelled from the pump, each of the casings having a shoulder portion which extends radially over said annular region and is adapted and arranged to abut with the shoulder portion of the other casing, a seal between the shoulder portions, and releasable clamping means for releasably holding together the two casings about the seal.

One embodiment of a diaphragm pump in accordance with the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side view of a diaphragm pump in accordance with the present invention, showing in double chain-dotted lines an alternative position for the pivotable lever which operates the pump, Figure 2 is an enlarged sectional view of the clamps used in the pump of Figure 1, taken along line Il-Il in Figure 1, Figure 3 is an exploded side view of the pump of Figure 1 with some parts shown in section and some parts omitted for clarity, and Figures 4, 5 and 6 are front, bottom and rear views of the pump of Figure 1.

Referring to the drawings, there is shown a diaphragm pump 1 which includes a housing formed from a first concave casing 2 and a second concave casing 4. The two casings abut one with the other about a common flat annular region between a shoulder 6 on the first casing and an opposing shoulder 8 on the second casing.

Lying between the two casings is a diaphragm constituted by a circular flexible plastics membrane 10, having two circular plates 12 and 14 associated therewith for the purpose of imparting rigidity to a central area of the membrane. The circular plastics diaphragm membrane 10 incorporates two integral ridges 1 6, 1 8 of frusto-conical cross-section, one on each side of the membrane. Each of these ridges lies near to the edge of the circular membrane on a circle which is concentric with the membrane; each ridge is arranged to be received by associated channels 20,22, also of frusto-conical cross-section, provided respectively in the shoulder 6 of the first casing 2 and in the opposing shoulder 8 of the second casing 4.The provision of the ridges 1 6, 1 8 and associated channels 20, 22 gives an improved fluid-tight seal between the diaphragm and the two casings of the pump.

The two said casings 2 and 4 are held together with the diaphragm gripped between their respective shoulder portions 6 and 8 by means of four releasable clamps 24, shown in more detail in Figure 2. As will be seen from Figure 2, each of the clamps 24 consists of a hook-shaped member 26, having a foot 28 with an upstanding projection 30 which engages a corresponding groove 34 provided in the rear face 36 of a radially extending flange 38 on the outer periphery of the second casing 4, and a main body 40 with a screwthreaded bore 44 for receiving a bolt 42.The shank of each of the bolts 42 passes through a respective bore 46 provided in each of four overhanging ledges 48 which project radially outwardly from the outer periphery of the said first casing 2 beyond the outer periphery of the shoulder 8 of the second casing and engages the screw-threaded bore 44 of the hook-shaped member 26. Upon tightening the four bolts 42, the shoulder 6 of the first casing is drawn towards the shoulder 8 of the second casing and the diaphragm member 10 is gripped fluid-tightly therebetween.

Liquid to be pumped enters the pump through an inlet 50 in the wall of the first casing 2 and leaves the pumping chamber 52 through an outlet 54 also provided in the wall of the first casing 2.

Each of the inlet and the outlet have a one-way valve 32 associated therewith which permits flow of liquid in one direction only. Any suitable valve may be used but a simple valve which we have found suitable is a flap of semi-rigid rubber or plastics held in position across the face of the respective inlet and outlet.

In the illustrated embodiment the inlet 50 and the outlet 54 have been shown to be disposed in a diametrically opposed relationship, but they need not be so disposed. Thus, the inlet and outlet can be positioned so that their respective longitudinal axes are inclined to one another, for example as shown by the chain-dotted outlines drawn in Figure 6.

The diaphragm is operated by a lever 56 which passes into the interior of the second casing 8 through an opening 60 provided in the casing. The inner end of the lever has two arms 63 between which there is carried a socket 62, pivotally mounted about axis 64, for receiving a bolt 66.

The bolt 66 secures the diaphragm 10 to the end of the lever 56 by passing through holes provided in the centre of the diaphragm membrane 10 and in its associatedi pates 12 and 14, and engaging the said socket 62. The lever itself is pivoted about a fulcrum pin 58 passing through the lever and the walls of the casing. The end 67 of the lever which projects outwardly of the casing is formed into a tubular portion for receiving a handle 68, only part of which is shown. In order to make the pump more versatile, the lever and second casing are designed so that the lever can be located in a second position as shown by the double chaindotted lines drawn in Figures 1 and 3.In this second position, the lever passes into the casing through an opening 70 provided in the second casing at a position diametrically opposite opening 60, is pivoted about a second fulcrum position 72, and is connected to the diaphragm 10 in the same way as described above for the first lever position.

For ease of mounting the pump, two sets of holes in mutually perpendicular planes are provided on the second casing. The first set of holes 74 is located on a flat rear portion 75 of the second casing (see Figure 6) and can be reached easily via openings 60 and 70, while the second set of holes 76 is located two wings 78 extending laterally from the top of the second casing (see Figure 5).

Easy access to the interior of the pump is provided by means of a readily removable cover 80 which covers an access port provided in the first casing 2. The cover 80 is kept in position by a crank-handle 82 which can be rotated about its mountings 84 in turrets 85 so that its off-set portion 86 either bears against the cover 80 when in position on the casing or releases the cover 80 so that it can be removed. To ensure that access to the interior of the pump is not obstructed, the crank-handle 82 is designed so that it can be fully withdrawn from turrets 85. In order to make the join between the cover 80 and the first casing fluid-tight, the cover and the periphery of the access port on the first casing both have grooves 86, 88 of frusto-conical section for accommodating a seal 87 having a cross-section represented by two frusto-conical areas lying base to base.

Although the embodiment described above has been shown with four clamping members, the pump can be arranged to have more such clamps if necessary, and in some cases less than four clamping members can be used.

In use, the pump is mounted on a suitable service by fixing means passing either through holes 74 or 76, with the lever 56 passing out through the top of the casing as shown in Figures 4, 5 and 6. The bolts 42 of the clamping means 26 are loosened and the first casing 2 is rotated relative to the second casing 4 until the inlet 50 and the outlet 54 are in the desired position, whereupon the bolts 42 are tightened to fasten the clamping means 26. To pump water or another liquid through the pump, the handle 68 is moved to and fro, either by hand or by a suitable' mechanical device. Movement of the handle away from the pump displaces the diaphragm 10 towards tie rear race 35 or the pump and causes water to be drawn into the pumping chamber 52 through valved inlet 50.Movement of the handle in the opposite direction sweeps the diaphragm across the pumping chamber towards the front and cover 80 of the pump which forces the liquid in the pumping chamber to be expelled therefrom via valved outlet 54.

Should one wish to change the position of the inlet and outlet relative to the position of the handle and rear of the pump, it is a simple matter to loosen the bolts 42, turn the first casing through a desired angle and re-tighten the bolts.

If one wishes to reverse the direction of flow of liquid through the pump, one merely loosens bolts 42 until the projections 30 on the clamps 26 can be released from groove 34 thereby to release the first casing 2 from the second casing 4, rotates the first casing so that the inlet and outlet positions are interchanged and reassembles the first and second casings and the clamps 26.

Should the pump become blocked, the cover 80 can easily be removed by rotating the crankhandle 82 to release the cover and removing the crank-handle from its mountings in turrets 85.

Removal of the cover affords easy access to the interior of the pump without disturbing the pipework of the pump or the pump mounting.

If the first position of lever 56 is inconvenient, one can readily remove the first casing 2 from the second casing 4 in the manner described above, and to disconnect the diaphragm 10 from the socket 62 on lever 56. By removing the fulcrum pin 58, one can dismount lever 56 from its first position and remount it in the alternative position described above with a fulcrum at 72. Thus the socket-end of the lever is passed through opening 70 in the second casing 4, and the fulcrum pin 58 mounted at the fulcrum 72. The diaphragm 10 is reconnected to the socket 62 of the lever 56 and then the first casing 2 is re-assembled on the second casing 4 by re-locating the clamps 26 in groove 30 and tightening the bolts 42 until a fluidtight seal between the first and second casings is obtained.

Preferably the pump is of light-weight construction. Thus for example, the first casing 2 and its cover 80 are suitably made of molded plastics, while the second casing 4 and the pivotable lever 56 are cast from aluminium.

Thus it will be seen that the present inventiori provides a pump with few parts which is easy tq manufacture, and which an operator can easily assemble and take apart. The pump described above is of light-weight and is easy to maintain making it particularly suitable for selling to the general public. It has the important advantage described above that the position of the inlet and outlet can easily be altered thereby making the pump more easy to mount in small, confined spaces.

Claims (19)

1. A diaphragm pump comprising a housing formed from two concave casings which abut one with the other about a common flat annular region, one of the casings, the first casing, incorporating a valved inlet for admitting fluid to the pump and a valved outlet through which fluid can be expelled from the pump and each of the casings having a shoulder portion which extends radially over said annular region and is adapted and arranged to abut with the shoulder portion of the other casing, a seal between the shoulder portions, and releasable clamping means for releasably holding together the two casings about the seal thereby permitting rotational adjustment of one casing relative to the other about the axis of said annular region.

2. A pump according to Claim 1 , wherein the diaphragm of the pump comprises a flexible membrane which extends across the cavity formed by the two casings, the peripheral region of the membrane being clamped between the respective shoulder portions of the casings thereby to provide the said seal between the shoulder portions.

3. A pump according to Claim 1 , wherein on each major surface of the membrane, in the said peripheral region, there is provided a ridge of trapezoidal cross-section which is received by an associated channel in the respective shoulders of each casing.

4. A pump according to Claim 2 or 3, further including means for imparting rigidity to a central region of the diaphragm.

5. A pump according to Claim 4, wherein the said means for imparting rigidity comprises a pair of flat circular plates located one against each major surface of the diaphragm.

6. A pump according to any one of the preceding claims, wherein the releasable clamping means comprises at least two hook-shaped members, each having a body attached to a flange incorporating the shoulder portion of one of the said casings and a free end which engages in a groove in the rear face of a flange incorporating the shoulder portion of the other of said casings, the hook-shaped member being adjustable in a direction to selectively tighten and release the said casings about the seal.

7. A pump according to Claim 6, wherein the releasable clamping means comprises four of said hook-shaped members.

8. A pump according to any one of the preceding claims, wherein the diaphragm of the pump is reciprocated by means of a lever having an inner end pivotally linked to the diaphragm, an intermediate portion pivoted on first pivot points on the body of the second casing, and an outer end which projects externally of the second casing for driving of the pump.

9. A pump according to Claim 8, wherein the lever is releasably mounted in said first pivot points.

10. A pump according to Claim 9, wherein the second casing is provided with second pivot points in diametrically opposed relationship to said first pivot points whereby the lever can be mounted in a second operating position in which it projects externally of the casing in a direction diametrically opposite to its projection when mounted in the first operating position.

11. A pump according to any one of the preceding claims, wherein the first casing includes an access port having a removable cover for providing access to the interior of the pump.

12. A pump according to Claim 11, wherein the cover is held in place over the access port by a crank.

13. A pump according to Claim 12, wherein the crank is supported above the cover in two bearings and is rotatable in said bearings between a first position in which the crank does not engage with the cover and a second position in which the crank bears against the cover and urges it towards the access port.

14. A pump according to any one of Claims 11 to 13, including a seal between the access port and its cover, said seal having a transverse crosssection which is of the shape of two trapezia positioned base-to-base, said seal being received by associated grooves in the periphery of the access port and cover.

1 5. A pump according to any one of the preceding claims, wherein the inlet and outlet are positioned so that their respective axes are parallel.

1 6. A pump according to any one of Claims 1 to 14, wherein the inlet and outlet are positioned so that their respective axes are at an angle.

17. A pump according to any one of the preceding claims, wherein the first casing is made of a plastics material.

1 8. A pump according to any one of the preceding claims, wherein the second casing is cast from aluminium.

19. A diaphragm pump substantially as hereinbefore described with reference to the accompanying drawings.