BELLOWS WATER VALVE

FIELD OF THE INVENTION

The present invention relates broadly to a water valve assembly and relates particularly, although not exclusively, to a non-return valve, check valve or back flow prevention valve.

BACKGROUND OF THE INVENTION

Back flow valves, non-return valves and check valves are used throughout plumbing systems. Check valves of a duckbill configuration are relatively well known and used in the art of valves. The patent literature has a large number of patents disclosing duckbill valves including US patent nos. 3,901,272, 4,524,805, 3,822,720, 4,240,630 and 6,089,260. These patents similarly disclose a valve of a duckbill form having a slit at its outlet. The slit is designed to elastically deform and open when tension is applied about is periphery whereas closure of the slit is automatically provided by biasing stresses in the valve as a consequence of its shape.

The prior art of US patent no. 996,588 and German patent no. 4,033,818 describe variants of the duckbill check valves of the preceding art. Both US 996,588 and DE 4,033,818 are valves of a generally conical shape designed to permit flow in a single direction only. US 996,588 is a check valve with a transverse slit through a relatively thick apex portion of the valve which is tensioned under fluid pressure to elastically deform and open. DE 4,033,818 is a pressure relief valve having a discharge aperture at its apex which opens and releases pressure at a predetermined pressure. The valve of DE 4,033,818 is constructed of a highly elastic synthetic resin or rubber which is biased closed but under pressure is stressed about the discharge aperture which is opened.

The applicants (or their predecessors) of international patent application no. PCT/AUOO/00659 disclose a non-return valve having a valve diaphragm of a conical - shape. The valve diaphragm which is constructed of a resiliently flexible material includes a collapsible aperture which is exposed so as to open under fluid pressure on an upstream side of the valve. The valve diaphragm is tensioned or stressed about the collapsible

aperture and the wall thickness of the diaphragm is reduced toward its apex to facilitate this opening of the valve.

These check or non-return valves suffer from at least the following problems:

(i) the differential pressure required across the valve to effect its opening is relatively high;

(ii) the valve may be designed to reduce this differential pressure for opening but then is less resistant to reverse flow pressures; and

(iii) the valve in its open condition does not provide great flow throughputs as the throat restriction of the slit or collapsible opening is relatively high.

SUMMARY OF THE INVENTION

According to the present invention there is provided a water valve assembly comprising: a valve housing including a valve seat; a valve head being arranged to contact the valve seat; and biasing means including a resiliently deformable bellows connected to the valve head and defining a fluid passageway about its outside surface, the biasing means being prestressed to urge the valve head into said contact with the valve seat whereby in use fluid pressure against the valve head unseats it from the valve seat to allow the fluid to flow along the fluid passageway outside the bellows.

Preferably the valve head includes guiding means for alignment of the valve head within the fluid passageway during sliding movement of the valve head within the housing. More preferably the guiding means includes a radial protrusion connected to the valve head. Even more preferably the radial protrusion is in the form of one of a plurality of spokes connected to and radiating outwardly from the valve head.

Preferably the valve head includes a ring seal for contact with the valve seat on seating of the valve head.

Preferably the valve head includes a supplementary seal in the form of a lip seal. More preferably the lip seal has an inner surface for receiving a portion of the fluid on closure of

the valve head, the fluid urging the lip seal into sealing contact with the valve seat. Still more preferably the lip seal includes an outer surface for sealing contact with the valve seat.

Preferably the valve seat includes a stop for limiting compression of the lip seal on sealing contact of the outer surface with the valve seat. More preferably the stop is in the form of the ring seal.

Preferably the bellows is elongated and includes an inner opening at an opposite end to the valve head, the inner opening being designed for equalisation of fluid pressure inside and outside the bellows.

Preferably the water valve assembly also comprises a support member connected to the bellows at an opposite end to the valve head, the support member being mounted within the valve housing for prestressing of the resiliently deformable bellows. More preferably the support member includes an outer ring member housed coaxially within the housing and a plurality of radial members interconnecting the outer ring member and the bellows. Still more preferably the radial members are radial ribs. Even still more preferably the support member includes outer fluid openings adjacent each of the radial ribs, the outer fluid openings being a continuation of the fluid passageway outside the bellows. Alternatively the base portion includes a radial flange having one or more fluid openings.

Preferably the water valve assembly further comprises mounting means being detachably connected to the valve housing for retention of the valve head and bellows within said housing. More preferably the mounting means includes a screw threaded connector designed to abut the outer ring member on connection to the housing.

Preferably the valve seat is an inwardly directed annular flange.

Preferably the valve assembly is a cylindrical valve assembly having the valve head and bellows housed coaxially within the valve housing.

Preferably the valve head and bellows are of a unitary design.

BRIEF DESCRIPTION OF THE FIGURES

In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a water valve assembly will now be described in some detail, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a cross-sectional view of one embodiment of a water valve assembly according to the invention, the valve being closed;

Figure 2 is a cross-sectional view of the same embodiment of the valve assembly according to the invention, the valve being opened;

Figure 3 is a cross-sectional view taken through AA of Figure 2;

Figure 4 is a cross-sectional view taken through BB of Figure 2;

Figure 5 is a cross-sectional view of a valve head and a bellows according to another embodiment of the invention; and

Figure 6 is a cross-section view of a valve head and a bellows according to yet another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Figures 1 and 2 depict one embodiment of a water valve assembly generally depicted as 10 according to the invention. The valve assembly 10 comprises a valve housing 14 including a valve seat 12. In this embodiment, the valve seat is defined by an inwardly directly annular flange 12. The valve assembly 10 also comprises a valve head 16 which contacts the valve seat 12 for closure of the valve assembly 10. The valve assembly 10 further comprises biasing means in the form of an elongate bellows 18 connected to the valve head 16. As shown in figure 1, the bellows 18 is resiliently deformable and pre-stressed, or slightly compressed in its closed state within the valve housing 14, so that it urges the valve head 16 towards and into sealing contact with the valve seat 12.

The flow of fluid 20 in a forward direction through the open valve assembly 10 is shown in figure 2. Force or pressure from the fluid 20 applied to the valve head 16 from the

direction of the valve seat 12 unseats the valve head 16 allowing the fluid 20 to pass through the valve assembly 10. The opening of the valve 10 is effected provided the force exerted by the fluid 20 is greater than the force exerted in an opposite direction by the bellows 18 combined and by fluid pressure in a reverse flow direction 22.

As shown in figure 4, the valve head 16 includes guiding means which in this embodiment are radial protrusions in the form of spokes 24 connected to and radiating outwardly from the valve head 16. The guiding means or spokes 24 ensure that the valve head 16 remains coaxially aligned with the valve housing 14 during sliding movement of the valve head 16 within the housing 14. The use of relatively thin spokes 24 reduces obstruction of a fluid passageway 26 that is formed between the resiliently deformable bellows 18 and the valve housing 14. The fluid 20 that flows through the valve assembly 10 flows through the fluid passageway 26 outside the bellows 18.

As shown in figure 1, the valve head 16 includes a ring seal 28 for contact of the valve seat 12 on seating of the valve head 16. The sealing is enhanced as the force exerted by the reverse fluid flow 22 on valve head 16 increases. The valve head 16 also includes a supplementary seal in the form of a lip seal 30. The lip seal 30 has an inner surface 32 for receiving a portion of the fluid 20 on closure of the valve head 16. The fluid urges the lip seal 30 into sealing contact with the valve seat 12. The seal is formed by the contact of an outer surface 34 of the lip seal 30 with the valve seat 12. The ring seal 28 also acts as a stop for limiting compression of the lip seal 30 at high fluid pressures, preventing damage of the lip seal 30.

In this embodiment, the valve assembly 10 also comprises a support member 36 connected to the bellows 18 at an opposite end to the valve head 12. The support member 36 is shown in cross-section in figure 3. The support member 36 includes an inner central opening 46 for equalisation of fluid pressure inside and outside the bellows 18. This pressure equalisation reduces the likelihood of the bellows 18 being deformed or distorted by fluid pressure.

The support member 36 is mounted within the valve housing 14 by mounting means 38. In this embodiment the mounting means 38 is detachably connected by way of a screw thread 40 cut into both the valve housing 14 and the mounting means 38. The mounting of the

support member 36 allows for the pre-stressing of the bellows 18. In this embodiment the support member 36 includes an outer ring member 42 housed coaxially within the valve housing 14 and a plurality of radial members in the form of radial ribs, such as 44 defining outer fluid openings, such as 48. The outer fluid openings 48 are a continuation of the fluid passageway 26 outside the bellows.

In one embodiment of the invention (not shown), the support member 36 has a screw thread on its outside circumference. This enables the support member 36 to be detachably connected to the threaded valve housing 14 without the use of separate mounting means such as 38. It will be appreciated that other methods of mounting the support member, such as a bayonet mount, or a press fit could also be used.

In another embodiment (not shown), the valve housing is a cartridge or cage. The cartridge or cage may be split longitudinally and hinged for insertion of the valve head 16, bellows 18 and support member 36. It will be understood that the cartridge makes installation of the water valve assembly simpler. In yet another embodiment (not shown), the valve housing is a plastic cage that is inserted into a brass housing, the cage comprises parts that can be connected together enclosing a valve assembly.

In the illustrated embodiment, the valve assembly is a cylindrical valve assembly 10 having the valve head 16 and bellows 18 housed coaxially within the valve housing 14. Furthermore, in this embodiment the valve head, bellows and base portion are of a unitary design.

Figure 5 is a cross-section view of a valve head 60, a bellows 62 and an outer ring member 64 according to another embodiment of the invention. The valve head 60 is urged into a valve seat, similar to the valve seat 12 of figure 1, to form a seal. The absence of a lip and O-ring seal enables reduction in the circumference of the valve head 60 resulting in higher flow rates. Alternatively, the absence of a lip and O-ring seal enables the opening of the aperture in the valve seat 12 resulting in higher flow rates. The bellows 62 of this embodiment has a stiffer bellows to promote sealing than the embodiment shown in figures 1-3. Figure 6 is a cross-sectional view of a valve head 68, a bellows 62 and an outer ring member 64 according to yet another embodiment of the invention. This embodiment is

similar to that shown in figure 5 with similar components similarly numbered. This embodiment includes an O-ring seal 66 to improve sealing still further.

Now that a preferred embodiment of the invention has been described, it will be apparent that it has the following advantages:

(i) the differential pressure required across the valve assembly to effect its opening is relatively low;

(ii) the valve assembly has minimal leakage and remains closed at relatively low differential pressures;

(iii) the valve assembly is highly resistant to reverse flow pressures; and

(iv) the valve assembly in its open condition allows relatively high flow throughputs.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. For example, the valve assembly may be of a square rather than cylindrical cross-section, and the valve head, bellows and support member may be separable rather than being of a unitary design. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

It is to be understood that any acknowledgment of prior art in this specification is not to be taken as an admission but this acknowledged prior art forms part of the common general knowledge in Australia or elsewhere.