WO2007054669A1

WO2007054669A1 - Diaphragm pump and valve therefore

Info

Publication number: WO2007054669A1
Application number: PCT/GB2006/004092
Authority: WO
Inventors: Robert William Stimpson; James Edward Self
Original assignee: Dlp, Limited
Priority date: 2005-11-09
Filing date: 2006-11-02
Publication date: 2007-05-18
Also published as: GB0601040D0; GB2432195A; GB2432196A; GB2432196B; GB0522845D0

Abstract

A reciprocating diaphragm shower drain pump (10) comprises a diaphragm housing (12), a waste water inlet port (26) on or in fluid communication with the diaphragm housing (12), a waste water outlet port (28) on or in fluid communication with the diaphragm housing (12), an elastomeric flap valve seal (32) for closing at least one of the waste water inlet port (26) and the waste water outlet port (28), and a torsion bar spring (34) which positively biases the elastomeric flap valve seal (32) to a closed position.

Description

DIAPHRAGM PUNP AND VALVE THEREFORE

The present invention relates to a reciprocating diaphragm shower drain pump.

Reciprocating diaphragm shower drain pumps are known and used to assist drainage from a shower area. However, problems occur with sealing of the discharge line valve during operation. In particular, when the pump is being initially primed, and is thus drawing air instead of water, the discharge valve has a tendency not to seal fully across the discharge port. This problem is exacerbated when particulate matter and detritus, such as hair and skin, become trapped across the discharge port. The problem of poor sealing is also evident when the pump is discharging downwards or if operating as part of a low-head system.

Although less frequent, a similar problem can also occur at the inlet port of the pump, whereby a valve will fail to seal correctly.

The present invention seeks to provide a solution to this problem.

According to a first aspect of the present invention, there is provided a reciprocating diaphragm shower drain pump for pumping liquid, the diaphragm pump comprising a diaphragm housing, a waste water inlet port on or in liquid communication with the diaphragm housing, a waste water outlet port on or in liquid communication with the diaphragm housing, an elastomeric flap valve seal for closing at least one of the waste water inlet port and the waste water outlet port, and a torsion bar spring which positively biases the elastomeric flap valve seal to a closed position.

Preferable and/or optional features of the first aspect of the invention are set forth in claims 2 to 10, inclusive.

According to a second aspect of the present invention, there is provided an elastomeric flap valve seal for a reciprocating diaphragm pump in accordance with the first aspect of the invention, in combination with a torsion bar spring for positively biasing the elastomeric flap valve seal to a closed position.

Preferable and/or optional features of the second aspect of the invention are set forth in claims 14 to 17, 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 is apian view of one embodiment of a reciprocating diaphragm shower drain pump, in accordance with the first aspect of the invention;

Figure 2 is a horizontal section taken through a valve inlet body, valve discharge body, valve body portion and diaphragm housing of the pump shown in Figure 1; Figure 3 is a perspective view in the direction of a water outlet port of a valve discharge body and a valve inlet body of the pump shown in Figure 1, with diaphragm housing and elastomeric flap valve seal removed from the valve discharge body for clarity and showing a torsion bar spring;

Figure 4 is an enlarged view of the valve discharge body shown in Figure 3, with torsion bar spring removed for clarity; and

Figure 5 is an enlarged perspective view of the torsion bar spring.

Referring to the drawings, there is shown a reciprocating diaphragm shower drain pump 10 which comprises a diaphragm housing 12 in which is housed a reciprocating diaphragm 14 coupled to a connecting rod 16 driven by an electric motor 18. These elements of the pump 10 are common, and thus further description is omitted.

The diaphragm housing 12 includes a valve body portion 20 to which is engaged or integrally formed a valve inlet body 22 and a valve discharge body 24. The valve body portion 20 of the diaphragm housing 12 has a waste water inlet port 26 and a waste water outlet port 28, and the valve inlet body 22 and the valve discharge body 24 are in fluid communication with the inlet port 26 and the outlet port 28, respectively.

A first elastomeric flap valve seal 30 is interposed between the valve inlet body 22 and the inlet port 26 of valve body portion 20 of the diaphragm housing 12, and a second elastomeric flap valve seal 32 is interposed between the valve discharge body 24 and the outlet port 28 of the valve body portion 20 of the diaphragm housing 12. The first elastomeric flap valve seal 30 opens into the valve body portion 20 of the diaphragm housing 12, and seals against the valve inlet body 22 to close the inlet port 26; and the second elastomeric flap valve seal 32 opens into the valve discharge body 24 and seals against the valve body portion 20 of the diaphragm housing 12 to close the outlet port 28.

As best seen in Figure 3, a torsion bar spring 34 is provided in the valve discharge body 24. The torsion bar spring 34 includes a bar element 36 which contacts a downstream facing surface 38 of the second elastomeric flap valve seal 32 (see Figure 2), and which extends in parallel with a first hinge axis Pl (which extends perpendicularly into the plane of the paper in Figure 2) of the second elastomeric flap valve seal 32. The torsion bar spring 34 also includes two spaced arm elements 40 which extend in parallel, or substantially in parallel, from opposite ends of and generally perpendicular to the bar element 36.

Each of the arm elements 40 of the torsion bar spring 34 includes a spring coil 42 (best seen in Figure 5) by which the bar element 36 of the torsion bar spring 34 is biased against the second elastomeric flap valve seal 32 to urge it into sealing contact with the valve body portion 20 of the diaphragm housing 12. The spring coils 42 enable the arm elements 40 of the torsion bar spring 34 to hinge or bend about a second hinge axis P2. The second hinge axis P2 of the torsion bar spring 34 is coaxial with, or as close as possible to and parallel with, the first hinge axis Pl of the second elastomeric flap valve seal 32, so as to prevent or limit relative movement between the bar element 36 of the torsion bar spring 34 and the elastomeric flap valve seal 32, thus eliminating or reducing abrasion.

A torsion bar spring 34 is particularly beneficial, since the gauge of material can be easily altered, the arm length can be adjusted, and the number of coils 42 and the diameter of the coils 42 can be changed to enable a multitude of adjustments to be performed depending upon the installation environment and requirements of the pump

10. The material of the torsion bar spring 34 is preferably Grade 302 stainless steel conforming to BS2056 type 302S26. Stainless steel is preferable, since it is less likely to fatigue when compared to, for example, plastics, and it also has good corrosion resistance characteristics. However, other materials meeting these criteria could be used.

In this way, the urging force characteristics of the torsion bar spring 34 against the elastomeric flap valve seal 32 can be matched to the physical properties of the elastomeric material of the second flap valve seal 32 and the maximum force exertable by the torsion bar spring 34 when the elastomeric flap valve seal 32 is fully open, since this influences the pressure transmitted to the fluid within the in use diaphragm housing 12.

Other kinds of biasing elements, aside from a torsion bar spring, could feasibly be used. However, the above-described torsion bar spring 34 is beneficial since it does not or hardly obstructs the flow path of fluid from the diaphragm housing 12. It is envisaged that a leaf type spring could be utilised instead. However, a leaf spring cannot be as easily adjusted to suit a given installation. The torsion bar spring 34 or other biasing element is engaged with the valve discharge body 24. In this case, engagement is made via two pockets 44, best seen in Figure 4, integrally formed on an interior surface of the valve discharge body 24. Free ends 46 of the arm elements 40 of the torsion bar spring 34 are push- fit inserted into respective said pockets 44, thus retaining the torsion bar spring 34 adjacent to, and permanently in contact with, the elastomeric flap valve seal 32.

The biasing element can be retained in any other suitable way. For example, the biasing element can be retained or sandwiched between the valve body portion 20 and the valve discharge body 24 and/or valve inlet body 22 utilising screw-threaded fasteners which hold the assembly together, thus securely locating the biasing element in place.

The second elastomeric flap valve seal 32 itself includes a reinforcing element

48, which can take the form of an increased thickness of material, or an additional part applied to the downstream facing surface 38 of the elastomeric flap valve seal 32. In the case of an additional part, this can be formed of metal, for example stainless steel, and can be of cruciform shape to enable the bar element 36 of the torsion bar spring 34 to bear thereagainst. This kind of reinforcing element can be integrally formed as part of the elastomeric flap valve seal 32, or applied post-forming. It is envisaged that the biasing element, whether a torsion bar spring or other type of biasing element, can be formed integrally with the elastomeric flap valve seal, so that the hinge axes Pl and P2 are completely coaxial.

It is also envisaged that the elastomeric flap valve seal and spring can be sold separately as a replacement part or modifying part for an existing reciprocating diaphragm shower drain pump.

Although difficulties are found primarily with the sealing of the second elastomeric flap valve seal on the valve discharge body, the use of a spring, and in particular the use of a torsion bar spring, to aid in sealing the first elastomeric flap valve seal to the valve inlet body can also be utilised.

Although preferable to utilise to spaced parallel arm elements, preferably with coil windings, a single arm element could be utilised. The single arm element can extend centrally or substantially centrally relative to the flap valve seal, and may or may not include the coil winding. Alternatively, the single arm element can extend along or adjacent to one side of the flap valve seal.

It is thus possible to provide a reciprocating diaphragm shower drain pump having one or more elastomeric flap valve seals which positively seal. The use of the torsion bar spring allows a vast number of reliable operations of the elastomeric flap valve seal without undue wear and failure, thus simply and effectively increasing the reliability of the pump. The provision of the torsion bar spring enables straightforward and cost-effective tailoring of the spring characteristics for a given installation environment and requirements.

The embodiments described above are given by way of examples only, and 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 reciprocating diaphragm shower drain pump for pumping liquid, the diaphragm pump comprising a diaphragm housing (12), a waste water inlet port (26) on or in liquid communication with the diaphragm housing (12), a waste water outlet port (28) on or in liquid communication with the diaphragm housing (12), an elastomeric flap valve seal (30, 32) for closing at least one of the waste water inlet port (26) and the waste water outlet port (28), and a torsion bar spring (34) which positively biases the elastomeric flap valve seal (30, 32) to a closed position.

2. A reciprocating diaphragm shower drain pump as claimed in claim 1, wherein the elastomeric flap valve seal (32) closes the waste water outlet port (28).

3. A reciprocating diaphragm shower drain pump as claimed in claim 1 or claim 2, wherein the torsion bar spring (34) is positioned downstream of the elastomeric flap valve seal (30, 32).

4. A reciprocating diaphragm shower drain pump as claimed in any one of the preceding claims, wherein the torsion bar spring (34) is positioned to prevent or limit relative movement between the torsion bar spring (34) and the elastomeric flap valve seal (30, 32).

5. A reciprocating diaphragm shower drain pump as claimed in claim 4, wherein a pivot axis of the torsion bar spring (34) is coaxial with a pivot axis of the elastomeric flap valve seal (30, 32).

6. A reciprocating diaphragm shower drain pump as claimed in claim 4, wherein a pivot axis of the torsion bar spring (34) is parallel with a pivot axis of the elastomeric flap valve seal (30, 32).

7. A reciprocating diaphragm shower drain pump as claimed in any one of the preceding claims, wherein the torsion bar spring includes a bar element (36) which contacts the elastomeric flap valve seal (30, 32) and which extends in parallel with a pivot axis of the elastomeric flap valve seal (30, 32), and two spaced arm elements (40) which extend in parallel from the bar element (36).

8. A reciprocating diaphragm shower drain pump as claimed in claim 7, wherein each said arm element (40) of the torsion bar spring includes a coil (42) by which the bar element (36) of the torsion bar spring is biased against the elastomeric flap valve seal (30, 32).

9. A reciprocating diaphragm shower drain pump as claimed in any one of the preceding claims, wherein the elastomeric flap valve seal (30, 32) includes a reinforcing element (48) to prevent or limit deformation of the elastomeric flap valve seal (30, 32) by the biasing element (34).

10. A reciprocating diaphragm shower drain pump as claimed in claim 9, wherein the reinforcing element (48) is of cruciform shape.

11. A reciprocating diaphragm shower drain pump substantially as hereinbefore described with reference to the accompanying drawings.

12. An elastomeric flap valve seal for a reciprocating diaphragm pump as claimed in any one of the preceding claims, in combination with a torsion bar spring (34) for positively biasing the elastomeric flap valve seal (30, 32) to a closed position.

13. A combination as claimed in claim 12, wherein the torsion bar spring (34) includes a bar element (36) which contacts the elastomeric flap valve seal (30, 32) and which extends in parallel with a pivot axis of the elastomeric flap valve seal (30, 32).

14. A combination as claimed in claim 13, wherein the torsion bar spring (34) further includes two spaced arm elements (40) which extend in parallel from the bar element (36).

15. A combination as claimed in claim 14, wherein each said arm element (40) of the torsion bar spring includes a coil (42) by which the bar element (36) of the torsion bar spring is biased against the elastomeric flap valve seal (30, 32).

16. A combination as claimed in any one of claims 12 to 15, wherein the elastomeric flap valve seal (30, 32) includes a reinforcing element (48) to prevent or limit deformation of the elastomeric flap valve seal (30, 32) by the torsion bar spring (34).

17. A combination as claimed in claim 16, wherein the reinforcing element (48) is of cruciform shape.

18. An elastomeric flap valve seal for a reciprocating diaphragm pump as claimed in any one of claims 1 to 12, in combination with a biasing element (34), substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings.