WO2000043700A1

WO2000043700A1 - Pressure limiting valve

Info

Publication number: WO2000043700A1
Application number: PCT/NZ1999/000226
Authority: WO
Inventors: Robert Nicholas Edward Bolus
Original assignee: Methven Limited
Priority date: 1999-01-20
Filing date: 1999-12-23
Publication date: 2000-07-27
Also published as: AU766691B2; AU1900800A

Abstract

This invention relates to a pressure limiting valve of co-axial or in-line type. The valve includes an inlet chamber, an outlet chamber, a valve seal assembly in the inlet chamber, a moveable valve member in the outlet chamber and a port between the inlet and the outlet chambers, the port openable or closeable by axial movement of the valve member into and out of contact with sealing means of the valve seal assembly, the valve member biased at rest, by biasing means, away from the sealing means to leave the port open, and wherein, in use, substantially no surface of the valve member is subject to an axial force from pressure in the inlet chamber. The valve member may include stabilising means to maintain axial alignment of the valve member in the valve. The valve seal assembly may include a seal which is engaged on a support member by peripheral portions only of the seal. The invention also includes the valve member and valve seal assembly used in a pressure limiting valve of the invention. In one embodiment of a pressure limiting valve to the invention the valve seal assembly is engageable within the inlet body portion of the valve after assembly of the other portions of the valve.

Description

PRESSURE LIMITING VALVE

FIELD OF INVENTION

This invention relates to a pressure limiting valve, and in particular an in-line pressure limiting valve.

BACKGROUND

Pressure limiting or reducing valves are adapted to effect a reduction in pressure of a fluid passing through the valve, by automatic means, so that the outlet pressure is substantially constant irrespective of fluctuations in the inlet pressure.

Traditionally, pressure control valves have been reasonably bulky, particularly where the valve components have been oriented transverse to the flow. The development of coaxial or in-line pressure limiting valves has enabled such valves to be produced in a form which is less obtrusive in that the difference in diameter of the valve in comparison with that of the inlet and outlet portions is much less.

In order to provide more accurate control over outlet pressure, pressure limiting valves have included pressure-compensation systems. One such system is described in New Zealand Patent Specification No. 21 7527 which included a central passageway through the valve member to provide equal and opposite inlet pressures on either side of the valve member. The valve member is therefore only responsive to fluctuations in outlet pressure. Such pressure compensation systems add complexity to the valve.

Another factor which influences the efficiency of a pressure limiting valve is the extent to which the valve enables substantially coaxial flow of fluid through the valve. The greater the disturbance to that coaxial flow the less efficient the valve. The valve sealing component in most valves includes a washer which is secured to the valve seat by means of a centrally positioned securing means. Even where the washer is recessed into the washer holder, this still provides an opportunity for fluid, under pressure, to be forced behind the washer around the peripheral edges. The problems which result include damage to the washer, and a tendency to produce unacceptable noise, such as whistling. This can be a particular problem in pressure limiting valves including pressure compensation systems.

A further problem or complexity, associated with known pressure limiting valves concerns the method of assembly of these valves. New Zealand Patent Specification No. 223946 discloses a pressure limiting valve having three main parts, an inlet portion, a mid-portion and an outlet portion. The valve seal forms a part of the inlet portion, whilst the valve member is engaged within the mid-portion between the inlet portion and the outlet portion. Not only does this require three interconnecting parts, but also the valve sealing component must be assembled before the various components are interconnected, and is only accessible by disassembly.

New Zealand Patent Specification No. 21 7527 discloses a pressure limiting valve having only two main parts, with the inlet and outlet portions directly interconnected. However, again the jumper valve and valve seal must be completed and installed before interconnection of the two main parts, and are not accessible without disassembly.

It is an object of the present invention to provide a pressure limiting valve which reduces or overcomes at least some of the abovementioned problems, or which at least provides the public with a useful alternative.

Other objects of the invention may become apparent from the following description which is given by way of example only. SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided a pressure limiting valve of coaxial or in-line type and including an inlet chamber, an outlet chamber, a valve seal assembly in the inlet chamber, a moveable valve member in the outlet chamber, and a port between the inlet and the outlet chambers said port openable or closeable by axial movement of the valve member into and out of contact with sealing means of the valve seal assembly, the valve member biased at rest, by biasing means, away from the sealing means to leave the port open, and wherein in use, substantially no surface of the valve member is subject to an axial force from pressure in the inlet chamber.

Preferably the valve member includes stabilising means to maintain axial alignment of the valve member.

In one preferred form the valve member may include a valve body including a central bore, and an outer skirt having a shoulder portion, an outer face of the shoulder portion within the outlet chamber and subject to fluid pressure in that chamber.

Preferably, stop means may be provided to limit axial movement of the valve member at its open position so that the shoulder portion remains exposed to outlet pressure when the valve is in its fully opened position.

Preferably, the stabilising means may include oppositely disposed axial extensions of the valve member to form first and second contact points, longitudinally spaced apart, said first contact point between the valve member and an inner wall of the inlet body and the second contact point between the valve member and an inner wall of the outlet body.

Preferably, the stabilising means may further include a peripheral portion of the outer skirt, said peripheral portion substantially in axial alignment with the central bore and forming a third contact point, between the valve member and the outlet body.

In a further preferred form the central bore may include an inner profile adapted to facilitate axial flow through the bore.

According to a further aspect of the present invention there is provided a pressure limiting valve of coaxial or in-line type and including an inlet chamber, an outlet chamber, a valve seal assembly in the inlet chamber, a moveable valve member in the outlet chamber and a port between the inlet and the outlet chambers said port openable or closeable by axial movement of the valve member into and out of contact with sealing means of the valve seal assembly, the valve member biased at rest, by biasing means, away from the sealing means to leave the port open, and wherein the valve seal assembly may include sealing means engaged by engagement means on a support member, the engagement means engaging the sealing means by peripheral portions only.

Preferably, the sealing means may comprise a cup washer.

Preferably, the engagement means may include a ring portion adapted to form a tight engagement of the peripheral wall of the washer cup over the support member.

Preferably, the engagement means may further include spaced- apart legs projecting from the retaining ring such that when ends of the legs abut a surface the retaining ring is spaced apart from that surface by the legs.

Preferably, spaces between the legs of the engagement means may form the port.

In a further preferred form the valve seal assembly may be engageable within the valve through the inlet port after the body portions of the valve have been assembled. According to a further aspect of the present invention there is provided a pressure limiting valve of coaxial or in-line type including an inlet body portion engageable with an outlet body portion, with a valve member engaged between the inlet body portion and the outlet body portion in a manner enabling axial movement of the valve member to position a valve seat of the valve member in contact with or spaced apart from a valve seal within the inlet body portion, the valve seal part of an assembly engageable within the inlet body portion after assembly of the other portions of the valve.

According to a further aspect of the present invention there is provided a valve member for a pressure limiting valve substantially as herein described and with reference to the accompanying drawings.

According to a further aspect of the present invention there is provided a valve seal assembly for a pressure limiting valve substantially as herein described and with reference to the accompanying drawings.

Other aspects of the present invention may become apparent from the following description which is given by way of example only and with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 shows a cross-sectional view of a valve according to the invention in one preferred form, in a closed configuration;

FIGURE 2 shows a cross-sectional view of the valve of Figure 1 in a open configuration;

FIGURE 3 shows an exploded view of a valve assembly of Figures 1 and 2. FIGURE 4 shows a cross-sectional view of a valve of the invention in an alternative embodiment, in an open configuration.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference to the Figures, a valve 1 of the present invention includes an inlet body 2, an outlet body 3, a jumper valve 4 and a valve seal assembly 5.

The inlet body 2 includes inlet port 6, inlet chamber 7 and jumper valve support surface 8. A recess 9 is included in the bore of the inlet body 2 to accommodate a spring clip 1 0 adapted to retain the valve seal assembly 5 in the inlet body 2 in an assembled valve. A second recess 1 1 is included in the jumper valve support surface 8 to accommodate an O-ring 1 2 for sealing engagement between the jumper valve 4 and the jumper valve support surface 8.

The outlet body 3 includes an outlet port 1 5, an outlet chamber 1 6 and outer wall portion 1 7 adapted at the end 1 8 to engage with the inlet body 2 (for example by screw thread). Spring chamber 1 9 is formed between the outer surface of a front part 20 of the inlet body, and the internal surface of the outer wall portion 1 7 of the outlet body 3. The spring 22 (in Figure 3) is not shown in Figures 1 and 2.

An air vent 14 is provided through the outer wall portion 1 7 to facilitate movement of the jumper valve 4.

In a mid-portion of the outlet body 3, a recess 23 in the wall of the outlet chamber 1 6 is adapted to accommodate an O-ring 24 to form sealing engagement between the jumper valve 4 and the wall of the outlet chamber 1 6.

The valve seal assembly 5 has a base portion 30 adapted to form a snug engagement within the inlet body 2, a central member 31 , a washer support surface 32, a washer 33 and a washer retaining ring 34. The central member 31 may, for example, be formed from a series of veins or webs 39 radiating from a central axis, each web 39 connecting the base portion 30 with the washer support surface 32. The webs 39 can be seen in Figure 3. In that embodiment there are 6 webs, but more or less could be included. The washer 33 is a "cup" washer which fits over the washer support surface 32. Washer retaining ring 34 engages over the peripheral sides 35 of the washer 33, securely engaging it on the washer support surface 32.

The washer retaining ring 34 as best seen in Figure 3, includes legs 36 extending from one side of the ring. In an assembled valve the ends 37 of the legs 36 abut against a stop 38 formed by an end portion of the inlet chamber 7.

It will be appreciated that the valve seal assembly enables sealing engagement of the washer 33 on the washer support surface 32 without the need for any central hole in the washer, and excluding any access of fluid around the periphery of the washer, which with conventionally secured washers results in damage to the washer and/or unacceptable noise levels, such as a whistling noise.

The jumper valve 4 includes valve seat 40, internal shoulder portions 41 , outlet extension 42, and lateral extension 43. The lateral extension 43 extends outwardly from the main body of the jumper valve to form outer shoulder portion 44, which in an assembled valve is in the outlet chamber 1 6. Outer portion 45 of the lateral extension 43 is substantially parallel to but spaced-apart from the main body of the jumper valve 4 and has a buttress-type end 46 which, in use, engages against the spring 22. Thus, the lateral extension 43 forms a "skirt" for the jumper valve 4.

The jumper valve 4 has a compact form and the seals required in an assembled valve to ensure that the spring chamber 1 9 remains dry (i.e. O-rings 1 2, 24) are relatively close together in terms of their longitudinal position in the valve. This enables the whole valve 1 to be produced in a relatively compact form. The valve member contacts an inner wall of the inlet body, at jumper valve support surface 8, and the internal sides of the outlet port 1 5, via outlet extension 1 6. This results in two longitudinally spaced-apart points of contact that provide axial stability to the valve member. The outer portion 45 of the "skirt" of the jumper valve 4, provides additional stability to the jumper valve 4 (i.e. inhibiting tilt) .

It will be appreciated that axial stability may also be provided where the o-rings 1 2, 24 are sufficiently separated longitudinally, and the jumper valve 4 is sufficiently long to extend over both seals.

To assemble a valve 1 , of the invention, the jumper valve 4 is positioned in the outlet chamber of the outlet body 3 and the inlet body 2 is then engaged with the outlet body 3. The valve seal assembly 5, may then be slid into the inlet port 6 of the assembled valve and secured in position by the spring clip 1 0. Thus, the body of the valve, including the jumper valve, can be fully assembled prior to introduction of the valve seal assembly. Furthermore, the valve seal assembly can be manufactured separately, if necessary. An added benefit of this design is that, with a suitably selected, removeable, spring clip 10 the valve seal assembly may be replaceable without the need to disassemble the valve.

An alternative assembly of a valve 1 of the invention is shown in Figure 4. This assembly differs from the embodiment of Figure 1 in that the inlet body 2 is formed in two parts, an inner portion 60 and an outer portion 61 . This enables the valve 1 to be employed with different inlet ports 6. This embodiment differs from the embodiment of Figure 1 also in that the valve seal assembly 5 is retained in the inlet body 2 by a shoulder 62 in the outer portion 61 , rather than by a spring clip 10. The assembly of a valve 1 in this modified form is also different in that the valve seal assembly 5 is first engaged in the inner portion 60, the outer portion 61 is then engaged with the inner portion 60, securing the valve seal assembly 5 in position, the jumper valve 4 is then positioned in the outlet chamber of the outlet body 3 and the formed inner body 2 is engaged with the outlet body 3. Operation of a valve as the present invention will now be described, with particular reference to Figures 1 and 2.

It will be appreciated that the jumper valve 4 is movable in an axial direction between a closed position (as shown in Figure 1 ) in which the valve seat 40 contacts the washer 33, to prevent the flow of fluid from the inlet chamber 7 to the outlet chamber 1 6, and an open position (as shown in Figure 2) in which the valve seat 40 of the jumper valve 4 is spaced apart from the washer 33 to allow fluid flow from the inlet chamber 7 to the outlet chamber 1 6 via opening 50.

The spring 22 provides a bias maintaining the jumper valve 4 in the open position. The internal profile of the jumper valve including the internal shoulder portions 41 and outlet extension 42 facilitate the flow of fluid through the valve with minimal disturbance. This is also facilitated by the shape of the inlet chamber. The direction of fluid flow is, at worst, at 90 ° to axial flow (i.e. no double back), thereby reducing any restriction of fluid flow.

The buttress type end 46 of the "skirt" of the jumper valve engaging with an internal shoulder 49 of the outer wall portion 1 7 of the outlet body 3 provides a stop for the jumper valve 4. This feature ensures that a gap 51 is maintained between the outer shoulder portion 44 of the jumper valve 4 and the opposing face 52 of the outlet chamber 1 6. Thus, fluid in the outlet chamber 1 6 acts on the outer shoulder portion 44 whether the jumper valve 4 is open or closed. Other areas of the jumper valve 4 also are subject to a closing force from the outlet fluid pressure, including the shoulder portions 41 and outer rim 53. If the fluid pressure in the outlet chamber increases such that the force on these surfaces of the jumper valve 4 exceed a predetermined level (determined by the force applied by the spring to maintain the jumper valve 4 in an open position), then the jumper valve 4 will close to shut off the supply of fluid. Once the outlet pressure has declined to a sufficient level the valve will open as the force applied by the spring overcomes the return force on the exposed surfaces of the jumper valve 4. The valve is designed to control pressure in the outlet chamber, and therefore to be sensitive to pressure changes in the outlet rather than the inlet. This is achieved in the present valve without the need for a pressure compensation system, by ensuring that there is no surface of the jumper valve 4 exposed to the inlet pressure in a way which would provide an axial force on the jumper valve 4. Thus, when the jumper valve 4 is in its closed position, as in Figure 1 , the only surface exposed to the inlet chamber 7 is the end outer face 54 and there would be no force in an axial direction on this face.

With the jumper valve 4 in its open position the only force of the inlet pressure on the jumper valve 4 is on the inner rim 55. Any such force would be relatively insignificant in comparison with the force of the outlet pressure on the outer shoulder portions 44, internal shoulder portion 41 and outer rim 53.

Thus, a pressure limiting valve of the present invention enables the pressure limiting function, substantially governed by the outlet pressure only, without the need for a pressure compensation system. In its open position, the design of the valve facilitates axial flow of fluid through the valve. The design of the valve, and particularly that of the jumper valve, enables the valve to be produced in a compact form. The valve seat assembly ensures that fluid pressure cannot interfere with the positioning of the washer, to damage it or cause unacceptable noises. Finally, in the embodiment of Figures 1 -3 the body of the valve is formed from only two parts, and the valve as a whole is designed to be put together easily, with the valve seal simply engaged through the inlet of an otherwise assembled valve.

Where in the foregoing description reference has been made to specific components or integers of the invention having known equivalents then such equivalents are herein incorporated as if individually set forth. Although this invention has been described by way of example and with reference to possible embodiments thereof it is to be understood that modifications or improvements may be made thereto without departing from the scope or spirit of the invention.

Claims

1 . A pressure limiting valve of co-axial or in-line type including an inlet chamber, an outlet chamber, a valve seal assembly in the inlet chamber, a moveable valve member in the outlet chamber and a port between the inlet and the outlet chambers, said port openable or closeable by axial movement of the valve member into and out of contact with sealing means of the valve seal assembly, the valve member biased at rest, by biasing means, away from the sealing means to leave the port open, and wherein in use, substantially no surface of the valve member is subject to an axial force from pressure in the inlet chamber.

2. A pressure limiting valve according to claim 1 further including stabilising means to maintain axial alignment of the valve member.

3. A pressure limiting valve according to claim 2 wherein the valve member includes a valve body having a central bore and an outer skirt having a shoulder portion, an outer face of the shoulder portion within the outlet chamber and subject to fluid pressure in that chamber.

4. A pressure limiting valve according to claim 3 further including stop means to limit axial movement of the valve member at its open position so that the shoulder portion remains exposed to outlet pressure when the valve is in its fully opened position.

5. A pressure limiting valve according to claim 2 wherein the stabilising means may include oppositely disposed axial extensions of the valve member to form first and second contact points, longitudinally spaced apart, said first contact point between the valve member and an inner wall of the inlet body and the second contact point between the valve member and an inner wall of the outlet body.

6. A pressure limiting valve according to claim 5 wherein the stabilising means further includes a peripheral portion of the outer skirt substantially in axial alignment with the central bore and forming a third contact point, between the valve member and the outlet body.

7. A pressure limiting valve according to claim 3 wherein the valve bore includes an inner profile adapted to facilitate axial flow through the bore.

8. A pressure limiting of co-axial or in-line type and including an inlet chamber, an outlet chamber, a valve seal assembly in the inlet chamber, a moveable valve member in the outlet chamber and a port between the inlet and the outlet chambers said port openable or closeable by axial movement of the valve member into and out of contact with sealing means of the valve seal assembly, the valve member biased at rest, by biasing means, away from the sealing means to leave the port open, and wherein the sealing means is engaged on a support member of the valve seal assembly by engagement means engaging the sealing means by peripheral portions only.

9. A pressure limiting valve according to claim 8 wherein the sealing means comprises a cup washer.

10. A pressure limiting valve according to claim 9 wherein the engagement means includes a retaining ring adapted to form a tight engagement of the peripheral wall of the cup washer over the support member.

1 1 . A pressure limiting valve according to claim 10 wherein the engagement means further includes spaced-apart legs projecting from the retaining ring such that when ends of the legs abut a surface the retaining ring is spaced-apart from that surface by the legs.

1 2. A pressure limiting valve according to claim 1 1 wherein spaces between the legs of the engagement means form the port.

1 3. A pressure limiting valve of co-axial or in-line type including an inlet body portion engageable with an outlet body portion, with a valve member engaged between the inlet body portion and the outer body portion in a manner enabling axial movement of the valve member to position a valve seat of the valve member in contact with or spaced- apart from a valve seal within the inlet body portion, the valve seal part of a valve seal assembly engageable within the inlet body portion after assembly of the other portions of the valve.

14. A valve member for a pressure limiting valve, the valve member including a valve body with a central bore, an outer skirt having a shoulder portion substantially perpendicular to the axis of the bore, and stabilising means adapted to maintain axial alignment of the valve member in a valve.

1 5. A valve member according to claim 14 wherein the stabilising means includes oppositely disposed axial extensions of the valve member to form first and second contact points, longitudinally spaced-apart, in use said first contact point formed between the valve member and an inner wall of an inlet body of a valve and the second point formed between the valve member and an inner wall of an outlet body of the valve.

1 6. A valve member according to claim 1 5 wherein the stabilising means further includes a peripheral portion of the outer skirt, said peripheral portion substantially in axial alignment with the central bore and adapted, in use, to form a third contact point, between the valve member and an outlet body of the valve.

1 7. A valve member according to claim 1 5 wherein the central bore has an inner profile adapted to facilitate axial flow through the bore.

1 8. A valve seal assembly for a pressure limiting valve, said valve seal assembly including a support member, sealing means engaged on the support member by engagement means and engaging the sealing means by periphal portions only.

1 9. A valve seal assembly according to claim 1 8 wherein the sealing means comprises a cup washer.

20. A valve seal assembly according to claim 1 9 wherein the engagement means includes a retaining ring adapted to form a tight engagement of the peripheral wall of the cup washer over the support member.

21 . A valve seal assembly according to claim 20 wherein the engagement means further includes spaced-apart legs projecting from the retaining ring such that when ends of the legs abut a surface the retaining ring is spaced-apart from the surface by the legs.

22. A pressure limiting valve substantially as herein described and with reference to the accompanying drawings.

23. A valve member susbstantially herein described in with reference to the accompanying drawings.

4. A valve seal assembly substantially as herein described with reference to the accompanying drawings.