WO2008119919A1

WO2008119919A1 - Diaphragm pump

Info

Publication number: WO2008119919A1
Application number: PCT/GB2007/001196
Authority: WO
Inventors: Robert William Stimpson; Christopher Parratt
Original assignee: Dlp Limited; Parratt, Jennifer
Priority date: 2007-04-02
Filing date: 2007-04-02
Publication date: 2008-10-09

Abstract

A diaphragm pump (10) comprises a housing (12), a flexible reciprocatable diaphragm (18) provided in or on the housing (12) and defining a pumping chamber in the housing (12), an inlet port (24) and an outlet port (26) in the pumping chamber, a check valve to prevent reverse flow through the inlet port (24), and a drive member (28) for connection to a drive mechanism (30) for reciprocatingly moving the diaphragm (18). The drive member (28) is provided on or in the diaphragm (18) and extends transversely to a direction of reciprocation of the diaphragm (18) so as to project from the housing generally in or about the plane of the diaphragm when the diaphragm is in an unloaded or undeformed condition.

Description

DIAPHRAGM PUMP

The present invention relates to a compact diaphragm pump, particularly but not exclusively for pumped shower drainage.

Diaphragm pumps are well known and have been used in many applications. However, known diaphragm pumps have a connecting rod which extends perpendicularly from one side of the diaphragm. The connecting rod transmits motive force from a drive mechanism to the diaphragm, so that the diaphragm is forced to reciprocate and thus pump. The connecting rod is thus in parallel with the direction of reciprocation of the diaphragm.

This arrangement has two distinct disadvantages. The first being that the pump is unduly bulky, due to the connecting rod and drive mechanism being positioned in parallel with the reciprocating direction, and a preferable orientation of ports into the pump housing is not always possible.

For pumped shower drainage applications, in particular, space beneath a shower tray or shower former, or space along a drainage path, typically being beneath floorboards or within concrete flooring, is necessarily limited. Trying to install a known diaphragm pump which essentially projects perpendicularly to a drainage flow path, due to the positioning of the connecting rod and drive mechanism, causes significant problems, due to the extra space required. The second disadvantage is that pumping can only occur on the side of the diaphragm opposite the connecting rod. This is limiting in applications which require twin pumps, for example in situations where two showers are provided.

The present invention seeks to overcome these problems.

According to the invention, there is provided a diaphragm pump comprising a housing, a flexible reciprocatable diaphragm provided in or on the housing and defining a pumping chamber in the housing, an inlet port and an outlet port in the pumping chamber, a check valve to prevent reverse flow through the inlet port, and a drive member for connection to a drive mechanism for reciprocatingly moving the diaphragm, the drive member being provided on or in the diaphragm and extending transversely to a direction of reciprocation of the diaphragm so as to project from the housing generally in or about the plane of the diaphragm when the diaphragm is in an unloaded or undeformed condition.

Preferable and/or optional features of the invention are set forth in claims 2 to 15, inclusive.

The present invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which :

Figure 1 shows a diagrammatic cross-sectional view of a first embodiment of a diaphragm pump, in accordance with the invention; Figure 2 shows a diagrammatic cross-sectional view of a second embodiment of a diaphragm pump, in accordance with the invention;

Figure 3 shows a diagrammatic cross-sectional view of a third embodiment of a diaphragm pump, in accordance with the invention; and

Figure 4 shows a diagrammatic cross-sectional view in a plane perpendicular to that of Figure 2, of a fourth embodiment of a diaphragm pump, in accordance with the invention.

Referring firstly to Figure 1, there is shown a first embodiment of a four-port diaphragm pump 10 for use as part of a pumped shower drainage system. The four-port diaphragm pump 10 comprises a housing 12 having first and second clam-shell shaped housing elements 14, 16. A flexible, typically elastomeric, diaphragm 18 is clamped between the first and second housing elements 14, 16. First and second pumping chambers 20, 22 are thus defined between the first and second housing elements 14, 16 and respective opposite surfaces of the diaphragm 18. The first and second pumping chambers 20, 22 are fluidly isolated from each other by the diaphragm 18 being interposed therebetween.

An inlet port 24 and an outlet port 26 are provided in each housing element 14, 16, and a check valve (not shown) to prevent reverse flow is provided at, or in a pipe connected to, each port 24, 26. The pump 10 also includes a drive member 28 for connection to a drive mechanism 30 for moving the diaphragm 18 in a reciprocating manner. By way of example, the drive mechanism 30 can be an electric motor shaft 35 driving a rotating cam 32 about which an end of the drive member 28 is attached. The cam 32 is shown diagrammatically in Figure 1.

The drive member 28 is a rigid or semi-rigid elongate element. The drive member 28 is embedded in the diaphragm 18 so as to project from one edge 34, and extends through the diaphragm 18 to, or substantially to, a central portion 36 thereof. The drive member 28 thus extends in or substantially in parallel with a plane in which the diaphragm 18 lies, and transversely, and more particularly substantially laterally, to a direction of reciprocation (indicated by arrow A in Figure 1) of the diaphragm 18.

Although the drive member is integrally formed with the diaphragm as a one-piece element, the drive member can be separately attached to an outer surface of the diaphragm, or the diaphragm can be formed from two parts between which the drive member is sandwiched.

The drive member 28 projects sideways from the diaphragm 18, and extends from a side 38 of the housing 12.

The drive member 28 acts as a lever. To this end, the diaphragm 18 is formed with an enlarged integrally formed one-piece pivot portion 40 which allows the pivoting movement of the drive member 28 at or adjacent to the edge 34 of the diaphragm 18. To aid pivoting and longevity of the diaphragm 18, the diaphragm 18 may beneficially also include a cranked portion 42 adjacent to an edge 44 which is opposite to the pivot portion 40. The cranked portion 42 forms a live hinge which accommodates reciprocating movement of the diaphragm 18.

In use, the drive member 28 is operated, thus increasing the volume of one of the pumping chambers 20, 22 whilst decreasing the volume of the other pumping chamber 20, 22. With the increasing volume, fluid, being either liquid or gas, is drawn into the pumping chamber 20, 22 through the respective check valve and inlet port 24, and the decreasing volume of the other pumping chamber 20, 22 causes fluid therein to be expelled through the respective check valve and outlet port 26.

When the drive member 28 is operated to move the diaphragm 18 to its opposite position, the pumping chamber 20, 22 with the initially higher volume decreases in volume, causing fluid to be expelled through the respective check, valve and outlet port

26, and the pumping chamber 20, 22 with the initially lower volume increases in volume, causing fluid to be drawn in through the respective check valve and inlet port

24.

Consequently, a double pumping action simultaneously moving two independent flows of fluid is achievable. Referring to Figure 2, a second embodiment of the diaphragm pump 10 is shown. This embodiment is similar to that described above, and therefore similar parts are referenced with similar numbers having '100' added thereto, and further detailed description is omitted.

The only difference between the diaphragm pump 10 of the first embodiment and diaphragm pump 110 of the second embodiments is that, rather than an integrally formed one-piece pivot portion 40, a separate axle element 146 is provided on which drive member 128 is pivoted. The axle element 146 is supported by housing 112 and passes through the diaphragm 118.

It is envisaged that the axle element need not necessarily be accommodated in the diaphragm, and may be solely supported by the housing.

Alternatively, the axle element may only be supported by the diaphragm, and not by the housing. This is advantageous, since the diaphragm and drive member can be formed as a single unit, which can then be easily mounted in the housing.

It is entirely possible that, when the twin pumping action is not required, one of the pumping chambers can be dispensed with. In this case, the diaphragm is clamped or attached in any suitable fashion to only one of the housing elements to form only a single pumping chamber with an inlet port and an outlet port. The diaphragm and the drive member remain as described above. In this modification, one side of the diaphragm can be open to atmosphere. The drive member is essentially an elongate lever. However, the shape of the drive member can vary, and it may be long and relatively slender, or it may be of a protruding plate-shape or bar-shape, for example.

Although the drive member can itself be flexible, in order to overcome the inherent stiffness of the diaphragm, the drive member must be less flexible than the diaphragm.

Check valves are described as being provided in the or each inlet and outlet port. However, in certain applications, the check valve in or at the or each outlet port can be dispensed with.

Furthermore, it may be possible to provide a single check valve unit which prevents reverse flow through both the inlet and outlet ports.

Further enhancements to the basic invention here described will be apparent to those skilled in the art, such as the addition of a second or additional drive members situated around the periphery of a diaphragm. For example, a second drive member can be provided to extend oppositely to the drive member shown in Figures 1 and 2. Additionally, or alternatively, for example, a further drive member can be provide in or on the diaphragm to extend at right angles to the drive member shown in Figures 1 and 2. To further illustrate the modifications described above, Figure 3 shows a third embodiment of a diaphragm pump. This embodiment employs similar features to those described above, and therefore similar parts are referenced with similar numbers having '200' added thereto, and further detailed description is omitted.

The pump 210 of this embodiment includes a second drive member 228 which extends in a direction substantially opposite to the first drive member 128. The second drive member 228 is spaced from the first drive member 128, and projects from a side of the housing 212, similarly to the above described embodiments. However, although both drive members 128 and 228 can be formed separately of, and/or externally on, the diaphragm, in this case they are encased within the diaphragm 218.

The second drive member 228 is pivoted via an axle element 246, similarly to the first drive member 128. However, pivoting can occur as described in the first embodiment.

The cranked portion 242 is provided at or adjacent to the central portion, instead of to one side.

When multiple drive members are provided, the cranked living hinge portion 242 may be beneficially located at the centre of the diaphragm to accommodate sympathetic oscillations of these multiple drive members to operate the pump. Such arrangements may be beneficially applied to pumping viscous liquids or solids in suspensions, or to enhance the performance of the pump over that achievable with a single drive member. Although multiple separate or independent drive member elements are suggested and shown in Figure 3, in the modifications described above, the drive members can be formed as a single integral drive member which extends from the perimeter of the diaphragm at multiple spaced positions or locations. The term 'drive members' is thus intended to also cover a single drive member which is driven at multiple spaced points. An example of a fourth embodiment of a diaphragm pump is shown in Figure 4, which depicts a section in a plane principally through the drive member 128 and in a plane also perpendicular to that of Figure 2, where the drive member 128', 128", projects through multiple pivot portions 40', 40", which are interspersed between clamping regions 34, 44.

The above-described diaphragm pump is intended for use as part of a pumped shower drainage system, and due to its sideways projecting drive member, the pump can be accommodated in narrow and confined spaces alongside a drainage path. However, the pump can be used in any pumping application suitable for a diaphragm pump in order to pump any flowable material, including liquids and gases.

The embodiments described above are given by way of examples only, and various other modifications will be apparent to persons skilled in the art without departing from the scope of the invention, as defined by the appended claims.

Claims

1. A diaphragm pump comprising a housing (12; 112; 212), a flexible reciprocatable diaphragm (18; 118; 218) provided in or on the housing (12; 112; 212) and defining a pumping chamber (20; 22) in the housing (12; 112; 212), an inlet port (24) and an outlet port (26) in the pumping chamber (20; 22), a check valve to prevent reverse flow through the inlet port (24), and a drive member (28; 128; 128'; 228) for connection to a drive mechanism (30) for reciprocatingly moving the diaphragm (18; 118; 218), the drive member (28; 128; 128'; 228) being provided on or in the diaphragm (18; 118; 218) and extending transversely to a direction of reciprocation of the diaphragm (18; 118; 218) so as to project from the housing (12; 112; 212) generally in or about the plane of the diaphragm (18; 118; 218) when the diaphragm (18; 118; 218) is in an unloaded or undeformed condition.

2. A diaphragm pump as claimed in claim 1, wherein the diaphragm (18; 118; 218) defines a second pumping chamber (22) in the housing (12; 112; 212) on an opposite side of the diaphragm (18; 118; 218) to the first said pumping chamber (20).

3. A diaphragm pump as claimed in claim 2, wherein the second pumping chamber (22) includes a second inlet port (24) and a second outlet port (26), a check valve being provided to prevent reverse flow through the second inlet port (24).

4. A diaphragm pump as claimed in claim 2 or claim 3, wherein the housing (12; 112; 212) includes two housing elements (14, 16) between which the diaphragm (18; 118; 218) is provided, the first pumping chamber (20) being provided in a first said housing element (14), and the second pumping chamber (22) being provided in the second said housing element (16).

5. A diaphragm pump as claimed in any one of the preceding claims, wherein one or more further check valves is/are provided to prevent reverse flow through the first said outlet port (26) and/or the second outlet port (26).

6. A diaphragm pump as claimed in any one of the preceding claims, wherein the drive member (28; 128; 128'; 228) is received within the diaphragm (18; 118; 218) and projects sideways therefrom.

7. A diaphragm pump as claimed in any one of the preceding claims, wherein the drive member (28; 128; 128'; 228) extends from one side of the diaphragm (18; 118; 218) to or substantially to a central portion (36) thereof.

8. A diaphragm pump as claimed in any one of the preceding claims, wherein the drive member (28; 128; 128'; 228) is a pivotable lever.

9. A diaphragm pump as claimed in claim 8, wherein a pivot of the lever is integrally formed as one-piece with the diaphragm (18; 118; 218).

10. A diaphragm pump as claimed in claim 8, further comprising a separate axle element (146; 246) which is supported by the housing (112; 212) and on which the lever is pivotably received.

IL A diaphragm pump as claimed in claim 10, wherein the axle element (146; 246) is received in the diaphragm (118; 218).

12. A diaphragm pump as claimed in any one of the preceding claims, wherein the diaphragm (18; 118; 218) includes a cranked portion (42; 242), the cranked portion (42; 242) forming a live hinge.

13. A diaphragm pump as claimed in any one of the preceding claims, wherein the drive member (28; 128) projects from a single location on the perimeter of the diaphragm (18; 118).

14. A diaphragm pump as claimed in any one of claims 1 to 12, wherein the drive member (128'; 228) projects from multiple spaced locations on the perimeter of the diaphragm (18; 218).

15. A diaphragm pump as claimed in claim 14, wherein the drive member (128;

228) includes a plurality of separate drive member elements.

16. A diaphragm pump substantially as hereinbefore described with reference to Figure 1, Figure 2, or Figure 3 of the accompanying drawings.