Diaphragm pump

Abstract

 A diaphragm pump (10) comprising:
a chamber (12) opening at opposite end portions to provide an inlet (14 and an outlet (16), and including an aperture (30) defined in a surface of the chamber between the inlet and outlet;
a flexible diaphragm (40) having an inner region (42) and an outer region (44), the outer region (44) sealing against the surface of the chamber surrounding the aperture to close off the aperture, the chamber and the diaphragm (40) thereby defining a passageway (50) providing fluid communication between the inlet and outlet;
a one-way inlet valve (25) coupled to the inlet (14) and a one-way outlet valve (27) coupled to the outlet (16);
the inner region (42) of the diaphragm (40) being reciprocatable within the chamber (12), whereby on reciprocation of the inner region fluid is drawn in via the inlet valve and expelled via the outlet valve,
wherein the diaphragm (40) is angled such that the plane of the diaphragm faces the outlet (16).

Description

[0001] The present invention relates to a diaphragm pump. The diaphragm pump of the present invention has particular, but not exclusive, application to the field of sewage pumping.

[0002] Sewage comprises a liquid medium carrying a large amount of solid material in suspension and often comprises pockets of gas such as methane or air.

[0003] The presence of gas pockets in the sewage can often impair the pump's efficiency due to compressibility of the gas.

[0004] The present invention has an object of providing a pump designed to allow it to purge itself of the gas pockets during normal operation.

[0005] In one aspect, the present invention provides a diaphragm pump comprising:
a chamber opening at opposite end portions to provide an inlet and an outlet, and including an aperture defined in a surface of the chamber between the inlet and outlet;
a flexible diaphragm having an inner region and an outer region, the outer region sealing against the surface of the chamber surrounding the aperture to close off the aperture, the chamber and the diaphragm thereby defining a passageway providing fluid communication between the inlet and outlet;
a one-way inlet valve coupled to the inlet and a one-way outlet valve coupled to the outlet;
the inner region of the diaphragm being reciprocatable within the chamber, whereby on reciprocation of the inner region fluid is drawn in via the inlet valve and expelled via the outlet valve,
wherein the diaphragm is angled such that the plane of the diaphragm faces the outlet.

[0006] When the pump is mounted for use, the outlet is preferably disposed at a greater height than the inlet.

[0007] Preferably, the upper surface defining the passageway slopes upwardly from the horizontal from generally midway between the inlet and outlet to adjacent the outlet. Preferably, the upper surface defining the passageway includes the diaphragm and the surface of the chamber surrounding the aperture, and the plane of the diaphragm slopes upwardly more steeply than does the surface of the chamber surrounding the aperture.

[0008] Preferably, the inlet and outlet are constructed to convey fluid therethrough in a generally horizontal direction.

[0009] In another aspect, the present invention provides a diaphragm pump mounted for use comprising:
a chamber opening at opposite end portions to provide an inlet and an outlet, and including an aperture defined in a surface of the chamber between the inlet and outlet, the inlet and outlet being constructed to convey fluid therethrough in a generally horizontal direction;
a flexible diaphragm having an inner region and an outer region, the outer region sealing against the surface of the chamber surrounding the aperture to close off the aperture, the chamber and the diaphragm thereby defining a passageway providing fluid communication between the inlet and outlet;
a one-way inlet valve coupled to the inlet and a one-way outlet valve coupled to the outlet;
the inner region of the diaphragm being reciprocatable within the chamber, whereby on reciprocation of the inner region fluid is drawn in via the inlet valve and expelled via the outlet valve,
wherein the outlet is disposed at a greater height than the inlet, and the upper surface defining the passageway slopes upwardly from the horizontal from generally midway between the inlet and outlet to adjacent the outlet.

[0010] In another aspect, the present invention provides a diaphragm pump comprising a chamber opening at opposite end portions to provide an inlet and an outlet, and including an aperture defined in a surface of the chamber between the inlet and outlet, the central axes of the inlet and outlet being arranged to be parallel to and offset from one another; a flexible diaphragm having an inner region and an outer region, the outer region sealing against the surface of the chamber surrounding the aperture to close off the aperture, the chamber and the diaphragm thereby defining a passageway providing fluid communication between the inlet and outlet; a one-way inlet valve coupled to the inlet and a one-way outlet valve coupled to the outlet; the inner region of the diaphragm being reciprocatable within the chamber, whereby on reciprocation of the inner region fluid is drawn in via the inlet valve and expelled via the outlet valve.

[0011] An exemplary embodiment of the present invention is described with reference to the accompanying drawing, referred to as Figure 1, which shows a cross-sectional view of a diaphragm pump in accordance with the present invention.

[0012] Referring to Figure 1, a diaphragm pump suitable for pumping sewage Is generally designated 10 and comprises a chamber 12 in the form of an elongate hollow body having openings at opposite ends, which is mounted for use on a support structure 1 by legs 13. The opening at the left-hand end of the chamber serves as an inlet 14 and the one at the opposite, right-hand ends serves as an outlet 16. The inlet and outlet 14, 16 are constructed to convey fluid therethrough in a direction indicated by arrows F. It will be noted that the pump is constructed and its mounting arranged such that the arrows F extend horizontally and that the outlet 16 is at a greater height than the inlet 14.

[0013] The inlet and outlet 14, 16 are each provided with annular connection flanges 18. The connection flanges 18 are right-angled flanges in that they occupy a plane at right-angles to the arrows F and serve as the means by which an inlet valve assembly 24, including a one-way inlet valve 25, and an outlet valve assembly 26, including a one-way outlet valve 27 are connected to the chamber 12.

[0014] It will be appreciated that the use of right-angled flanges 18 in this manner permits the connection of the valve assemblies 24, 26 to the chamber 12 such that the central axes of the valve assemblies conveniently and readily extend horizontally.

[0015] The pump 10 also includes an aperture 30 in an upper surface of the chamber 12 between the inlet 14 and the outlet 16, and a flexible diaphragm 40. The flexible diaphragm 40 includes an inner region 42 and an outer region 44, the latter sealing against the surface of the chamber surrounding the aperture 30, thereby closing-off the aperture 30. The volume enclosed by the diaphragm 40 and the chamber 12 may be thought of as a fluid passageway 50 providing fluid communication between the inlet and outlet. From an inspection of Figure 1, it may be seen that the plane of the diaphragm 40, illustrated by the line X-X¹, slopes upwardly from the horizontal by a small angle as does a portion 12a of the upper surface of the chamber neighbouring the outlet 16 by approximately the same angle. The pump 10 also includes a driving means 100 which is operable to reciprocate the inner region 42 of the diaphragm to and fro within the chamber in a direction indicated by the arrow D ( which is orthogonal to the line X-X¹ ).

[0016] In use, the driving means 100 reciprocates the inner region 44 of the diaphragm to and fro within the chamber 12. During the upstroke, the outlet valve 27 is closed and fluid is sucked into the passageway 50 via inlet valve 25. During the downstroke, the inlet valve 25 is closed and fluid is expelled from the outlet valve 27.

[0017] In use, there is a tendency for pockets of gas to collect in the chamber 12 in the region of the diaphragm 40. Air pockets form as a result of leaky pipe work or air being sucked in with the sewage during the previous upstroke. Methane pockets form as a consequence of the chemical breakdown of the sewage. These pockets have an adverse affect on the pump efficiency.

[0018] The differential height between the inlet 14 and outlet 16 and the upwardly sloping nature of the upper surface of the passageway 50, which in the described embodiment includes the diaphragm 40 and the upper surface portion 12a, promote the passage of the gas pocket to the outlet 16. Further, the angling of the diaphragm 40 relative to the horizontal such that it 'faces' the outlet ensures that a component of its motion during reciprocation takes place in the flow direction of fluid expelled from the outlet ( indicated by arrow F ). In this manner, the reciprocation of the diaphragm can propel the pockets of gas towards the outlet 16 and expel them therefrom.

[0019] In other embodiments ( not illustrated ), the angling of the diaphragm 40 can be further accentuated such that there is a differential in slope between for example, the diaphragm 40 and the portion 12a, whereby the above-mentioned propulsion effect is exaggerated.

[0020] Although the present invention has been described with heavy emphasis on a sewage pump, the principles of the present invention can also be employed in other fields where other media are pumped.

Claims

1. A diaphragm pump comprising:
   a chamber opening at opposite end portions to provide an inlet and an outlet, and including an aperture defined in a surface of the chamber between the inlet and outlet;
   a flexible diaphragm having an inner region and an outer region, the outer region sealing against the surface of the chamber surrounding the aperture to close off the aperture, the chamber and the diaphragm thereby defining a passageway providing fluid communication between the inlet and outlet;
   a one-way inlet valve coupled to the inlet and a one-way outlet valve coupled to the outlet;
   the inner region of the diaphragm being reciprocatable within the chamber, whereby on reciprocation of the inner region fluid is drawn in via the inlet valve and expelled via the outlet valve;
   wherein the diaphragm is angled such that the plane of the diaphragm faces the outlet.

2. A pump as in claim 1, when the pump is mounted for use, wherein the outlet is disposed at a greater height than the inlet.

3. A pump as in claims 1 or 2, wherein the upper surface defining the passageway slopes upwardly from the horizontal from generally midway between the inlet and outlet to adjacent the outlet.

4. A pump as in claim 3, wherein the upper surface defining the passageway includes the diaphragm and the surface of the chamber surrounding the aperture, and the plane of the diaphragm slopes upwardly more steeply than does the surface of the chamber surrounding the aperture.

5. A pump as in any preceding claim, wherein the inlet and outlet are constructed to convey fluid therethrough in a generally horizontal direction.

6. A diaphragm pump mounted for use comprising:
   a chamber opening at opposite end portions to provide an inlet and an outlet, and including an aperture defined in a surface of the chamber between the inlet and outlet, the inlet and outlet being constructed to convey fluid therethrough in a generally horizontal direction;
   a flexible diaphragm having an inner region and an outer region, the outer region sealing against the surface of the chamber surrounding the aperture to close off the aperture, the chamber and the diaphragm thereby defining a passageway providing fluid communication between the inlet and outlet;
   a one-way inlet valve coupled to the inlet and a one-way outlet valve coupled to the outlet;
   the inner region of the diaphragm being reciprocatable within the chamber, whereby on reciprocation of the inner region fluid is drawn in via the inlet valve and expelled via the outlet valve,
   wherein the outlet is disposed at a greater height than the inlet, and the upper surface defining the passageway slopes upwardly from the horizontal from generally midway between the inlet and outlet to adjacent the outlet.

7. A diaphragm pump comprising:
   a chamber opening at opposite end portions to provide an inlet and an outlet, and including an aperture defined in a surface of the chamber between the inlet and outlet, the central axes of the inlet and outlet being arranged to be parallel to and offset from one another;
   a flexible diaphragm having an inner region and an outer region, the outer region sealing against the surface of the chamber surrounding the aperture to close off the aperture, the chamber and the diaphragm thereby defining a passageway providing fluid communication between the inlet and outlet;
   a one-way inlet valve coupled to the inlet and a one-way outlet valve coupled to the outlet;
   the inner region of the diaphragm being reciprocatable within the chamber, whereby on reciprocation of the inner region fluid is drawn in via the inlet valve and expelled via the outlet valve.

Drawing