GB2144517A

GB2144517A - Pump diaphragm

Info

Publication number: GB2144517A
Application number: GB08419030A
Authority: GB
Inventors: Kerridge Robert Dunsford
Original assignee: Flynn L W & Co Ltd
Current assignee: Flynn L W & Co Ltd
Priority date: 1983-08-01
Filing date: 1984-07-26
Publication date: 1985-03-06
Also published as: NZ205100A; GB8419030D0; AU3124184A; AU581179B2

Abstract

A pump diaphragm (1) of flexible material comprises a central area (2), lying substantially in a first plane, a peripheral area (3) lying substantially in a second plane, and a connecting area (4) between the central area (2) and the peripheral area (3). The connecting area (4) is shaped so that said first plane and said second plane are displaced one from the other. The pump (not shown) comprises housing having an open face across which the diaphragm is positioned, means to clamp the diaphragm to said housing, a port or ports (15) in the housing wall, and driving means to move the diaphragm in reciprocating fashion, the diaphragm being positioned so that said central area is displaced outwardly of the peripheral area with respect to the housing. <IMAGE>

Description

SPECIFICATION Improvements in or relating to diaphragms or pumps This invention relates to a diaphragm and/or a pump and has been devised particularly though not solely for use as a milk pump.

Accordingly in one aspect the invention consists in a diaphragm of flexible material comprising a central area lying substantially in a first plane, a peripheral area lying substantially in a second plane, and a connecting area between said central area and said peripheral area, said connecting area being shaped so that said first plane and said second plane are displaced one from the other.

In a further aspect the invention consists in a pump having a diaphragm of flexible material comprised of a central area, lying substantially in a first plane, a peripheral area lying substantially in a second plane, and a connecting area between said central area and said peripheral area, said connecting area being shaped so that said first plane and said second plane are displaced one from the other, a housing having an open face across which said diaphragm is positioned, clamping means to clamp said diaphragm to said housing, a port or ports in said housing wall, and driving means to move said diaphragm in reciprocating fashion inwardly and outwardly relative to said housing, said diaphragm being positioned so that said central area is displaced outwardly of said peripheral area with respect to said housing.

To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

One preferred form of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a cross sectional view of a diaphragm according to one preferred form of the invention; and Figure 2 is a simplified diagrammatic cross sectional view of a pump according to one preferred form of the invention.

Referring to the drawings, a diaphragm and a pump are provided as follows: The diaphragm 1 has a central area 2, a peripheral area 3 and a connecting area 4.

The diaphragm is formed of a flexible resilient material, for example, a rubber material. The central area 2 and peripheral area 3 may be and desirably is of greater thickness than the connecting area 4. The connecting area 4 is shaped so that the general plane of the central area 2 is displaced from the general plane of the peripheral area 3 and in particular so that the front face 5 of the central area 2 is displaced rearwardly of the front connection position 6 between the peripheral area 3 and the connecting area 4. Thus the central area 2 lies substantially in a first plane and the peripheral area 3 lies substantially in a second plane, which planes are displaced one from the other.

To effect such a construction the connecting area 4 is preferably, in cross section, in the form of a flattened S-shape as can be seen from the drawings.

A connecting boss is provided to allow the diaphragm to be connected into a pump such as a milk pump and the boss of stiff material preferably comprises a threaded socket 7 having a flange 8 which is embedded in the material of the central area 2 of the diaphragm 1.

The periphery of the flange 8 is preferably formed to a bulbous cross section at at 9, so as to substantially reduce any tendency for the rubber material to tear at the end of the flange in use.

The dimensions of the diaphragm will depend on its particular use but for a 230 mm diameter diaphragm the peripheral area 3 could be about 20 mm wide and the thickness could be a little in excess of 20 mm. The thickness of the central portion 2 could be about 22 mm and the thickness of the connecting area 4 could be about 10 mm with a radius of curvature of the inner two curves 4a and 4b of about 9 mm. The width of the connecting area 4 may be about 42 mm.

The diaphragm 1 is used in a pump and to this end is engaged with a housing 10 which is substantially dish-shaped. The peripheral area 3 of the diaphragm 1 is engaged with a peripheral flange 11 of the housing 10 and may be clamped thereto by a clamping ring 1 2 mounting threaded studs 1 3 passing through suitable apertures in the flange 1 2 to be fixed by nuts 14. Thus the peripheral area 3 of the diaphragm 1 is substantially fixed with respect to the housing 1 0. A port 1 5 is provided into the housing 10 which is engaged by a conduit 1 6 which divides into inlet and outlet branches (not shown) and into which suitable non-return valves can be positioned. Of course separate inlet and outlet conduits could be provided if desired.

The diaphragm 1 is positioned so that the central area 2 is displaced outwardly with respect to the housing 10 and in order to impart a reciprocating motion to the central area 2, a shaft 1 7 is provided which is rotated by a suitable driving means such as a motor and an eccentrically mounted substantially circular disc or plate 1 8 is engaged with the shaft 1 7. A slip ring 1 9 is engaged about the plate 1 8 and a cylinder 20 is provided, fixed, for example, to the housing for the driving mechanism. Within the cylinder 20 moves a piston 21 having a connecting link 22 to the boss 7.

A further connecting link 23 is provided between the slip ring 19 and the piston 21.

Engagement between the link 23 and piston 21 being pivotal, for example, by the means of a pivot pin 24. Thus rotation of the shaft 1 7 will be converted into a reciprocal motion of the boss 7.

About the boss 7 may be positioned a nut 25 which positions a backing plate 26 against the back of the central area 2.

In use the shaft 1 7 is rotated thus causing the eccentric disc or plate 1 8 to rotate leading to a reciprocal motion of the piston 21 and therefore a reciprocal motion of the central area of the diaphragm 1.

The shape of the connecting area 4 is such that the central area 2 may readily be moved in such a reciprocal fashion thereby drawing material, such as milk or water, into the chamber 27 between the diaphragm 1 and the housing 10 and cyclically expelling that material.

Thus it can be seen that a diaphragm and a pump are provided which at least in the preferred form of the invention have the advantage that because of the displaced arrangement of the centre portion of the diaphragm from the peripheral portion, a substantial stroke of the pump may be achieved.

For example a substantially flat diaphragm of the usual size used in milking pumps is able to move with a stroke of about one and three-eighths inches.

It is believed that with the present arrangement a stroke of up to three inches with a diaphragm 1 of the size herein described will be obtainable. Also because of the particular shaping of the diaphragm it will be found that for the return stroke little return effort is required because of the shape of the construction. The movement of the diaphragm must therefore be limited to an extent wherein the rubber retains its memory and is not overstretched but notwithstanding this limitation as above stated, it is believed that a substantial stroke can be obtained.

Claims

1. A diaphragm of flexible material comprising a central area lying substantially in a first plane, a peripheral area lying substantially in a second plane, and a connecting area between said central area and said peripheral area, said connecting area being shaped so that said first plane and said second plane are displaced one from the other.

2. A diaphragm as claimed in Claim 1 wherein the material of said diaphragm is resilient.

3. A diaphragm as claimed in either Claim 1 or Claim 2 wherein said connecting area is substantially in the form of a flattened Sshape in cross section.

4. A diaphragm as claimed in any one of the preceding claims wherein said central area carries a connecting boss of stiff material, said connecting boss having a flange embedded in said central area.

5. A diaphragm substantially as herein described with reference to the accompanying drawings.

6. A pump having a diaphragm of flexible material comprised of a central area, lying substantially in a first plane, a peripheral area lying substantially in a second plane, and a connecting area between said central area and said peripheral area, said connecting area being shaped so that said first plane and said second plane are displaced one from the other, a housing having an open face across which said diaphragm is positioned, clamping means to clamp said diaphragm to said housing, a port or ports in said housing wall, and driving means to move said diaphragm in reciprocating fashion inwardly and outwardly relative to said housing, said diaphragm being positioned so that said central area is displaced outwardly of said peripheral area with respect to said housing.

7. A pump as claimed in Claim 6 wherein said diaphragm is formed of resilient material.

8. A pump as claimed in either Claim 6 or Claim 7 wherein said connecting area is substantially in the form of a flattened S-shape in cross section.

9. A pump as claimed in anyone of Claims 6 to 8 wherein said central area carries a connecting boss of stiff material, the connecting boss having a flange embedded in said central area and said driving means being connected to said boss.

10. A pump as claimed in any one of Claims 6 to 9 wherein said port is engaged by a conduit having inward and outward branches, and non-return valves in said branches to allow flow of material into said chamber through said inward branch and out of said chamber through said outward branch.

11. A pump as claimed in any one of Claims 6 to 10 wherein said driving means comprises a shaft, means to rotate said shaft, and an eccentrically positioned substantially circular plate on said shaft, a slip ring about said plate, a piston and cylinder, said piston being connected to said slip ring by a first connecting rod and said diaphragm by a second connecting rod.

1 2. A pump substantially as herein described with reference to the accompanying drawings.