HK1153799A - Valve - Google Patents

Description

Valve with a valve body

Technical Field

The present invention relates to valve devices, and in particular to hydraulically assisted valve devices. The valve device of the present invention has a significant advantage over prior art valve devices in that a significantly smaller displacement of its actuating member than prior art devices is sufficient to operate the valve. In solenoid valves, this results in a significantly lower operating power requirement.

Background

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgment or admission or any form of suggestion that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

The applicant has previously devised various valve arrangements which provide improvements and improvements over the prior art. One such device is described in the applicant's earlier international patent application PCT/AU96/00263, which employs a flow control element such that only a small flow is required to actuate the valve. The entire disclosure of this document should be considered to be incorporated herein by reference. In the above description, the applicant has previously invented various other valve arrangements for which a number of other applications have been filed in the name of Microflow Pty ltd.

Although the applicant's earlier invention has provided a considerable improvement over conventional prior art devices in that only a slight flow is required to operate the valve, the applicant has made further improvements and improvements to such valves, as described hereinafter.

Figures 1 and 2 show the most common arrangement known for use in hydraulic assist valves. Generally, reducing the activation power depends on the shortest distance the valve member needs to move under the influence of the activation power in order to achieve the desired flow.

FIG. 1 shows one arrangement of hydraulically assisted valves that continues to be employed by the industry to control flow rates of less than about 50L/min. This arrangement is commonly employed in the industry because the bypass flow rate requires slightly less axial piston movement than is required to induce the desired main flow.

FIG. 2 shows an arrangement of hydraulic assist valves that are employed by the industry to control flow rates greater than about 50L/min.

It should be noted that in fig. 1, the axial movement of the pressure reducing valve member 2 is equal to the axial movement of the main valve member 3 plus the axial movement required to open the pressure reducing port (reliefport). That is, the activation power of this arrangement is largely dependent on the relief port cross-section and the amount of displacement of the main valve member 3. In this example, the extent to which the start-up power is reduced by employing the cascade arrangement of fig. 2 is less significant than would justify the additional complexity exhibited by such an arrangement. However, the additional power associated with the large displacement required to control the greater flow rate becomes significant enough to justify the use of an arrangement such as that of fig. 2.

Unlike the arrangement of fig. 1, the displacement of the main valve member 2 in fig. 2 has no direct effect on the actuation power. That is, in this case, the activation power depends only on the relief port cross-section and the smaller displacement amount of the relief valve member (not the main valve member) displacement.

Disclosure of Invention

The present invention aims to overcome some of the disadvantages of the prior art.

The present invention seeks to provide an improved valve arrangement in which the power required to actuate the valve is reduced.

The present invention also aims to provide an improved valve arrangement in which a large displacement of the main valve member has no direct effect on the actuation power.

In one broad form, the present invention provides a valve apparatus comprising:

a fluid inlet;

a fluid outlet;

a main valve seat defining an aperture through which fluid may selectively flow from said inlet to said outlet;

a valve assembly movable relative to the main valve seat between an open position of the valve in which fluid may flow from the inlet to the outlet and a closed position of the valve in which fluid flow is prevented;

a control chamber, at least a portion of a wall of which is formed by the valve assembly, such that the volume of the control chamber is variable in dependence on the position of the valve assembly;

a fluid passage providing fluid communication between the fluid inlet and the control chamber; and

a control device controlling the position of the pressure relief valve member relative to the valve body of the valve assembly, thereby controlling movement of the valve assembly between the open and closed positions relative to the valve seat.

Preferably, the valve assembly comprises:

a valve body including a reduced-pressure inlet, a reduced-pressure valve seat defining a reduced-pressure outlet, and an internal cavity; and

a pressure reducing valve member movable within the internal cavity of the valve body between a first position in which the pressure reducing valve member is moved away from the pressure reducing valve seat to allow fluid flow from the pressure reducing inlet to the pressure reducing outlet and a second position in which the pressure reducing valve member abuts (abut) the pressure reducing valve seat to prevent fluid flow through the pressure reducing outlet.

Preferably, wherein the control means comprises any one or combination of electrical, mechanical, electromagnetic or other control means capable of initiating movement of the pressure reducing valve member relative to the valve body of the valve assembly.

Still preferably, wherein the relief valve member is formed at least in part of a resilient material so as to normally bias (normally bias) the relief valve member into either of the first or second positions.

In a preferred form, wherein the pressure reducing valve member is normally biased into the second (closed) position, to open the valve, the control means is activated to move the pressure reducing valve member away from the pressure reducing valve seat to cause fluid to flow from the pressure reducing inlet to the pressure reducing outlet, whereby, once the flow is caused, a change in fluid pressure assists the movement to cause the valve assembly to move away from the valve seat to open the valve and allow fluid to flow from the fluid inlet to the fluid outlet.

In another preferred form, wherein the pressure reducing valve member is normally biased into the first (open) position, to close the valve, the control means is activated to move the pressure reducing valve towards the pressure reducing valve seat to prevent fluid flow from the pressure reducing inlet to the pressure reducing outlet, whereby, once the flow is prevented, a change in fluid pressure causes the valve member to move against the valve seat to close the valve and prevent fluid flow from the fluid inlet to the fluid outlet.

Preferably, the pressure reducing valve member includes at least one projection, and preferably, a plurality of projections, made of an elastic material, extending into contact with the valve body of the valve assembly so as to bias the pressure reducing valve member relative to the valve body.

Still preferably, the apparatus further comprises:

a flow control member disposed within the fluid passage for restricting the flow of fluid within the fluid passage and substantially preventing the ingress of particles such as dust by entering the fluid passage, and, if any, the relative movement of the flow control member within the passage serves to dislodge such particles from the passage.

In yet another broad form, the present invention provides a valve arrangement comprising:

a valve seat defining an aperture through which the fluid can flow when the valve device is in an open position; and

a valve member adapted to move relative to the valve seat between an open position in which the valve member is at least partially moved away from the valve seat and a closed position in which the valve member abuts the valve seat to prevent fluid flow through the aperture;

characterised in that at least the end of the valve seat is made of a resilient material such that the valve seat can be compressed or deformed at least somewhat (to provide an improved seal between the valve seat and the valve member).

Preferably, whereby the movement of the valve member relative to the valve seat is any one or combination of translation, rotation, sliding pivoting, axial movement or other directional movement.

In another broad form, the invention provides a valve member adapted to be movably received within a valve body between a first position in which the valve member is moved away from a valve seat and a second position in which the valve device abuts the valve seat, the valve member including at least one projection, and preferably a plurality of projections, formed of a resilient material extending into contact with the valve body to bias the valve member relative to the valve body into at least one of the first or second positions.

Drawings

The present invention will be more fully understood from the following detailed description of the preferred, but not limiting, embodiments of the invention, which is described in conjunction with the accompanying drawings, in which:

FIG. 1 shows a prior art valve arrangement in FIGS. 1(a) and 1 (b);

FIG. 2 illustrates a prior art cascade valve apparatus;

figure 3 shows a preferred embodiment of a valve device according to the invention;

FIG. 4 shows the valve assembly (identified at 31) of the valve apparatus of FIG. 3 in a closed condition, FIG. 4(a) showing a cross-sectional view along line A-A;

FIG. 5 shows the valve device of FIG. 4 in an open state;

FIG. 6 illustrates an alternative preferred embodiment of the valve assembly of FIG. 4, with FIG. 6 showing this preferred embodiment of the valve assembly in an open state;

FIG. 7 shows a closed state of the valve of FIG. 6;

FIG. 8 shows a schematic view of an overall valve arrangement according to the present invention;

FIG. 9 shows an alternative arrangement of the valve in FIGS. 9a, 9b, 9c, FIG. 9a showing the closed position of the valve assembly, FIG. 9b showing the position of the valve just after actuation, and FIG. 9c showing the fully open position of the valve;

FIG. 10 illustrates a valve seat arrangement, FIG. 10a illustrates a prior art closed position, and FIG. 10b illustrates a prior art open position of a conventional valve assembly arrangement;

fig. 11 shows the arrangement of the valve seats according to the invention, fig. 11a shows the initial state of the valve seats, fig. 11b shows the closed state of the valve seats, fig. 11c shows the open state of the valve seats according to the invention; and

fig. 12 shows an alternative preferred arrangement of the valve seat according to the invention, fig. 12a showing the closed position of the valve seat and fig. 12b showing the open position of the valve seat.

Detailed Description

In all of the drawings, like reference numerals will be used to refer to like features except where explicitly indicated.

First, it should be appreciated that the present invention may relate to the applicant's earlier invention which is the subject of international patent application No. pct/AU 96/00263. Some or all of the disclosure of this earlier patent application may (but is not required to) be considered to be incorporated herein by reference.

Figure 3 shows a valve arrangement, generally indicated at 1, having a fluid inlet 4, a fluid outlet 5, a main valve seat 32 and a valve assembly, generally indicated at 31. It will be appreciated that the entire valve assembly 31 can move relative to the valve seat 32 to enable fluid to flow from the inlet 4 to the outlet 5. As can be seen in FIG. 3, the valve assembly, generally designated 31, includes a first body member 33, a second body member 34 and a pressure relief valve member 35 therebetween. The first body member 33 of the valve assembly 31 includes a reduced-pressure inlet 36 and a reduced-pressure valve seat 37 defining a reduced-pressure outlet 38. The second part 34 of the valve assembly has an internal cavity 39 in which a pressure reducing valve member 40 is disposed. Although the valve assembly 31 is shown as being formed of two parts 33 and 34, the valve assembly 31 may be formed of one part, or multiple parts, which may be sandwiched between the primary valve seat 32 and a spring-like electrically conductive biasing means, depending on the manner of manufacture. These components may be made of plastic metal material or other suitable material. During use, the relief valve member 40 located within the cavity 39 of these valve components 33 and 34 is adapted to move within the cavity 39. Preferably, the pressure reducing valve member 40 is at least partially made of an elastic material. In particular, the lower portion 41 having the projection 42 extending therefrom is preferably formed of an elastic material so that it assumes a normal position and can undergo deformation. Details of the types of deformations that may be experienced are shown in fig. 4 and 5.

Fig. 4 shows the closed state of the valve assembly portion 31 of the valve device 1 of fig. 3, while fig. 5 shows the open state of the valve of fig. 4. As shown in fig. 4, in the closed state, the resilient member 20 is relaxed so that its central region 21 abuts the valve seat 26, thus preventing flow from the inlet 36 to the outlet 38. Fig. 4(a) shows a cross-sectional view along line a-a of fig. 4.

Fig. 5 shows the resilient member 20 having been deformed, thereby causing the central region 21 to retract away from the valve seat 26, thereby allowing fluid to flow from the inlet 36 to the outlet 38. The activation of the valve assembly 31 to move the valve member 19 from the position shown in figure 4 to the position in figure 5 will now be described.

Fig. 6 shows an alternative preferred embodiment in which the valve is normally open in the relaxed state of the resilient member 20 to allow fluid flow from the inlet 36 to the outlet 38, and fig. 7 shows the closed state of the valve assembly of fig. 6 in which the resilient member 20 is in a deformed state, thereby blocking flow from the inlet 36 to the outlet 38.

It will be appreciated that the resilient member 20 may have a central region 21 and a plurality of arms 22 as shown in figure 4 (a). It will be appreciated that although three such arms are shown in figure 8, one arm or a plurality of arms may be provided. It should be noted that the resilient member 20 may be used with the valve arrangement described in this specification, or separately.

Referring again to fig. 3, there is also shown a control chamber 12 wherein at least a portion of the wall of the control chamber is constituted by a valve assembly 31 such that the volume of the control chamber 12 varies according to the position of the valve assembly 31. The fluid passage 7 provides fluid communication between the fluid inlet 4 and the control chamber 12, and a control means in the form of a solenoid 10 is also shown which controls the position of the pressure reducing valve member 40 relative to the valve body 34 of the valve assembly 31, thereby controlling the movement of the valve assembly 31 relative to the valve seat 32 between its open and closed positions.

It will be appreciated that the control means 10 may be an integral component of the second body member 34 (as is the case in figure 9) and/or any one or combination of electrical, mechanical, electromechanical or other control means capable of causing movement of the pressure relief valve member 40 relative to the pressure relief valve seat 37 of the valve assembly 31. It will be appreciated that in use, by employing a small amount of power to activate the solenoid 10, the pressure reducing valve member 40 may be moved slightly away from the valve seat 37 so that a small amount of fluid may flow from the inlet 36 to the outlet 38. Once this fluid flow occurs (which is allowed due to the fluid channel 7), the pressure within the chamber 12 is reduced. Due to the pressure drop in the chamber 12 (at least a part of the wall of the chamber 12 is constituted by the wall of the valve assembly 31), the valve assembly 31 moves away from the valve seat 32. It should be noted that there is a diaphragm-like arrangement 43 to ensure that a good seal is achieved between the control chamber and the inlet and outlet. It will therefore be appreciated that a small amount of fluid flow through the relief valve portion (which is created by fluid flow through passages 7, 36 and 38) is sufficient to cause movement of the valve assembly 31 from the closed position to the open position.

Similarly, to close the valve, the solenoid 10 may be deactivated such that the resilient member 20 (fig. 3) moves against the valve seat 37, thereby preventing fluid flow between the inlet 36 and the outlet 37. When this occurs, the fluid pressure in the chamber 12 again changes and re-equals the pressure in the inlet 4 as the inlet 4 is effectively opened through the fluid passage 7. The increased pressure in the chamber 12 thus forces the valve assembly 31 to close again against the valve seat 32, thereby closing the operation of the valve 1.

Fig. 8 shows a more general version of the valve arrangement of the present invention, in which the inlet port 4, the outlet port 5 and the control chamber 12 are again shown. The purpose of this device is to show that a wide range of components having various shapes, positions, etc. can be employed to achieve the functional operation of the present invention. Essentially, it is shown that the pressure relief valve portion 13 is activated by signaling the power source 10 to control the position of the valve member 3, which in turn delivers the required amount of power via a power linkage 11. Fig. 8 shows the valve 1 in the closed position, in which the state of the pressure-reducing valve portion 13 is changed in the following manner: which causes or allows the pressure reducing valve member 2 to block the pressure reducing port 9 so that the valve member 3 bears against the valve seat 6, thereby effectively preventing fluid flow from the fluid inlet 4 to the fluid outlet 5.

As shown in fig. 3, the flow control member 8 is provided in the fluid passage 7 to restrict the flow of fluid through the fluid passage 7, so that only a very small amount of fluid can flow through the fluid passage 7. The flow control member is also substantially effective in preventing the ingress of particles such as dust by entering the fluid passage 7 and the relative movement of the flow control member 8 within the passage 7 of the valve member 3 can be used to remove or expel such particles from the passage 7 if any enter. The self-cleaning operation described above has significant advantages over prior art devices that are prone to clogging. Such flow control members are more fully described in other patent applications of the applicant.

The flow control member 8 may be held in its optimal position by attachment to the wall of the control chamber 12 shown in figure 3, but it will be appreciated by those skilled in the art that the flow control member may also be held in place by attachment to the valve member 3, for example. The flow control member may be realized as a rigid rod made of metal or a similar material and its cross-sectional area should be chosen to be slightly smaller than the cross-sectional area of the fluid channel 7 (in which the flow control member is accommodated) in order to allow a very small fluid flow around it. This therefore provides the desired fluid flow restriction characteristics. Suitably sized holes can be readily formed when machining the fluid passageway, so that, in use, the amount of fluid flowing through the passageway 7 can be restricted by the mounting of the flow control member 8.

The uniqueness of the present invention is that the flow of fluid through the opening formed in the movable object is controlled by using only the energy required to control the flow, regardless of the position of the object relative to the control power source, which means that, unlike the conventional arrangement in fig. 1(a) and 1(b), the greater movement of the valve member 3 has no effect on the amount of power required to change the flow through the pressure relief port 9. The result is that only the small power required to open and close the pressure reduction port 9 is sufficient to cause a large movement of the valve member 3. This is a significant difference from the prior art.

Fig. 9 shows a further alternative valve arrangement to that shown in fig. 5 and 6, in which the relief valve portion 13 is constructed of material(s), such as an insulator or bimetal, and is attached to the valve member 3 in the following manner: when the energy state of the relief means 13 changes, the position of the relief valve member 2 relative to the sealing surface of the relief port 9 may also change, thereby controlling the operation of the device.

Generally, the manner in which the relief valve portion 13 controls flow through the relief port 9 is irrelevant, as this will depend on the corresponding signals used and the interfacing profile, state and condition of the sealing surfaces. Also, as is the case with the arrangement of the present embodiment and some of the above-described alternative arrangements, the means of the power linkage 11 is not limited to an elastic cable/conductive spring connection. Rather, it may be pneumatic, hydraulic, or any other form of powered linkage/transmission. Means for ensuring that the valve portion 13 tends to maintain a desired position relative to the valve member 3 may include, but are not limited to: spring/elastic material (which may also be used as said power linkage 11), a click-on attachment, a screw thread, gluing, interference fit or made as an integral part of the valve member 3, depending on the way of machining.

As mentioned previously, the valve member 3 is preferably formed at least in part from a flexible material. As shown in the figures, the central portion of the valve member 3 is preferably formed of a more rigid material. Hard rubber, possibly with metal, which is highly operable, is a suitable material. This allows for easy formation of fluid channels therein which are not as susceptible to cracking and tearing as the pores of prior art diaphragm members. The outer periphery of the valve device is preferably made of a more flexible material to allow the member to move to and from the valve seat 6 while providing good fluid sealing properties therearound. Rubberized materials are suitable.

Fig. 10 shows a conventional arrangement of a valve seat known in the prior art. The valve seat 50, which is of a conventional type, is typically formed of a hard material, whereby a valve member 51 (which is made of a somewhat softer material) may thus abut against the valve seat 50, as shown. As shown in fig. 10b, after long use, permanent deformation in the valve member 51 is liable to occur due to the constant pressure against the valve seat 50, the deformation being in the form of indentations 52 formed in the surface of the valve member 51. While this provides an adequate seal, it does tend to cause leakage when misalignment (misalignment) occurs.

In the valve apparatus of the present invention (as shown in fig. 4 and 5), it will be appreciated that when the resilient member 20 undergoes deformation from the position shown in fig. 4 to the position shown in fig. 5, the tip of the projection 22 will also cause some sliding movement of the resilient member 20. That is, as the resilient member is pulled up and down, the ends of the projections 22 slide inward and outward between the valve assembly components.

In such an arrangement, if the material described in fig. 10 is used, leakage may eventually occur due to misalignment of the various components.

Accordingly, the applicant proposes to use a harder material for the valve member 51 and a softer material for the valve seat 52 to enable minimal, if any, permanent deformation of the valve member 51.

As shown in fig. 11, fig. 11(a) shows initial states of various parts, fig. 11(b) shows closed states of the parts, and fig. 11(c) shows open states of the parts. It will be appreciated that any permanent deformation of the valve seat 50 will not result in any inferior sealing characteristics compared to the prior art arrangement shown in figure 10. That is, if the valve seat becomes slightly flattened or deformed, this also has no effect on the sealing characteristics, as compared to the arrangement of fig. 10.

However, the arrangement proposed by the applicant has significant advantages where the valve member may be subjected to or designed to have sliding movement relative to the valve seat.

This is illustrated in fig. 12, where it can be seen that when the valve member 51 undergoes sliding movement in the direction of arrow 53 relative to the valve seat 50, any deformation of the valve seat 50 will also have no or only a negligible effect on the force required for sliding movement and the sealing of the valve, however, if the arrangement of fig. 10 (prior art) is used, such sliding movement will require more force to achieve and result in poor sealing characteristics.

It will be appreciated that the arrangement shown in figures 11 and 12 may be used in conjunction with the valve 1 shown in figures 3 to 9, or with other valve arrangements. In essence, the valve apparatus arrangement of the present invention is characterised in that at least the end of the valve seat is formed from a resilient material to enable at least some compression or deformation of the valve seat, and it will therefore be appreciated that this therefore provides an improved seal between the valve seat and the valve member and allows sliding movement to be achieved with less force, regardless of the type of movement that the valve member may undergo, including but not limited to any one or combination of translation, rotation, sliding pivoting, axial movement, or other directional movement.

The invention has been described herein with reference to specific preferred embodiments. However, those skilled in the art will readily appreciate that many variations and modifications are possible in the preferred embodiments. All such variations and modifications are to be considered within the spirit and scope of the invention as broadly described above.

Claims (13)

1. A valve device comprising:

a fluid inlet;

a fluid outlet;

a main valve seat defining an aperture through which fluid may selectively flow from said inlet to said outlet;

a valve assembly movable relative to the main valve seat between an open position of the valve in which fluid may flow from the inlet to the outlet and a closed position of the valve in which fluid flow is prevented; a control chamber, at least a portion of a wall of the control chamber being formed by the valve assembly such that a volume of the control chamber is variable in dependence on a position of the valve assembly;

a fluid passage providing fluid communication between the fluid inlet and the control chamber.

2. The valve apparatus of claim 1, wherein the valve assembly comprises:

a valve body including a reduced-pressure inlet, a reduced-pressure valve seat defining a reduced-pressure outlet, and an internal cavity; and

a pressure reducing valve member movable within the internal cavity of the valve body between a first position in which the pressure reducing valve member is moved away from the pressure reducing valve seat to allow fluid flow from the pressure reducing inlet to the pressure reducing outlet and a second position in which the pressure reducing valve member abuts the pressure reducing valve seat to prevent fluid flow through the pressure reducing outlet; and

a control device controlling the position of the pressure relief valve relative to the valve body of the valve assembly, thereby controlling movement of the valve assembly between the open position and the closed position relative to the valve seat.

3. A valve arrangement according to claims 1 and 2, characterized in that the valve body of the valve assembly is formed of one or more parts which are connected together or held in a desired position relative to each other by any one or a combination of the following means: spring-like/resilient biasing means, snap-fit connection, threads, gluing, heat welding, ultrasonic welding or any other means of fixation.

4. A valve arrangement according to claim 3, wherein said spring-like/resilient biasing means is also used to provide a signal and/or power to activate said control means.

5. A valve arrangement as claimed in any one of claims 1 to 4, wherein the control means, which may or may not be an integral part of the valve assembly, comprises any one or combination of electrical, mechanical, electromagnetic or other control means capable of causing movement of the pressure reducing valve member relative to the valve body of the valve assembly.

6. A valve arrangement as claimed in any one of claims 1 to 5 wherein the relief valve member is formed at least in part from a resilient material so as to normally bias the relief valve member into either of the first or second positions.

7. A valve arrangement as claimed in claim 6 wherein the pressure reducing valve member is normally biased into the second (closed) position, and to open the valve the control means is activated to move the pressure reducing valve member away from the pressure reducing valve seat to cause fluid to flow from the pressure reducing inlet to the pressure reducing outlet, whereby once said flow is caused, a change in fluid pressure causes the valve assembly to move away from the valve seat to open the valve and allow fluid to flow from the fluid inlet to the fluid outlet.

8. A valve arrangement as claimed in claim 6 wherein the pressure reducing valve member is normally biased into the first (open) position and, to close the valve, the control means is activated to move the pressure reducing valve towards the pressure reducing valve seat to prevent fluid flow from the pressure reducing inlet to the pressure reducing outlet, whereby once said flow is prevented, a change in fluid pressure causes the valve assembly to move against the valve seat to close the valve and prevent fluid flow from the fluid inlet to the fluid outlet.

9. A valve arrangement according to any one of claims 6 to 8, wherein the pressure reducing valve member comprises at least one projection, and preferably a plurality of projections, made of resilient material extending into contact with the valve body of the valve assembly so as to bias the pressure reducing valve member relative to the valve body.

10. The valve apparatus according to any one of claims 1 to 9, further comprising:

a flow control member disposed within the fluid passage to restrict the flow of fluid within the fluid passage and substantially prevent the ingress of particles such as dust by entering the fluid passage, and, if any, the relative movement of the flow control member within the passage serves to dislodge these particles from the passage.

11. A valve device arrangement comprising:

a valve seat defining an aperture through which fluid can flow when the valve device is in an open position; and

a valve member adapted to move relative to the valve seat between an open position in which the valve member is at least partially moved away from the valve seat and a closed position in which the valve member abuts the valve seat to prevent fluid flow through the aperture;

characterised in that at least the end of the valve seat is made of a resilient material such that the valve seat can be compressed or deformed at least somewhat to provide an improved seal between the valve seat and the valve member.

12. A valve arrangement as claimed in claim 1, wherein the movement of the valve member relative to the valve seat is any one or combination of translational, rotational, sliding pivotal, axial or other directional movement.

13. A valve member adapted to be movably received within a valve body between a first position in which the valve member is moved away from a valve seat and a second position in which the valve device abuts the valve seat, the valve member comprising at least one projection, and preferably a plurality of projections, formed of a resilient material extending into contact with the valve body so as to bias the valve member relative to the valve body into at least one of the first or second positions.