GB2231640A - Valves - Google Patents

Abstract

A valve comprises a body 10 defining a through passageway 11, 12. There is a valve seat 13 within the passageway, a valve member 16 abutting the valve seat, the valve member being rotatable from a closed position, to an open position in which fluid flow can take place along the passageway through a passage 17 in the valve member, and spring means 18 urging the valve member into sealing engagement with the valve seat. in a preferred embodiment, the valve 13 comprises a rigid metal seat 14 and a resilient plastics seating member 15. The valve operates very effectively at high pressures but it seals efficiently even under low pressures or vacuum conditions, because of the sealing force provided by the spring 18. The preferred embodiment of the valve is fail safe in the event of a fire. High temperatures may cause the seating member 15 to melt, but if this happens, the spring 18 simply urges the ball 16 against the metal shoulder 14, bringing about a degree of resealing. <IMAGE>

Description

VALVES The invention relates to valves.

The invention provides a valve comprising a body defining a through passageway, a valve seat within the passageway, a valve member abutting the valve seat, the valve member being rotatable from a closed position, to an open position in which fluid flow can take place along the passageway through a passage in the valve member, and spring means urging the valve member into sealing engagement with the valve seat.

The spring means may comprise a compression spring.

Alternatively the spring means may comprise one or more disc springs.

Preferably the valve seat comprises a first rigid seat portion, for example of metal, and a second resilient seat portion, for example of plastics, the valve member normally engaging the resilient portion but the degree of compression of the spring means being such that if the resilient portion melts or is otherwise destroyed, the spring means is capable of moving the valve member into sealing engagement with the rigid seat portion.

Preferably, the degree of compression of the spring means is such as to seal the valve, in the closed position, regardless of which side of the valve is the high pressure side.

The rigid seat portion may be made of brass.

The resilient seat portion may be made of PTFE.

The valve member may have a connection to means for rotating the valve member, the connection permitting at least limited movement of the valve member under the influence of the spring means.

The spring means may abut directly against the valve member.

Alternatively, there may be a bearing member between the spring means and the valve member.

The valve member may comprise a ball member.

By way of example, a specific embodiment of the invention will now be described with reference to the single accompanying figure, which is a side view, partly in section and partly broken away, showing an embodiment of valve according to the invention.

The valve shown in the figure is intended for use as a gas meter control cock, and must therefore be capable of operating at -low pressures, for example, of less than 1 bar (gauge).

The valve comprises a brass body 10 defining a through passageway having an inlet end 11 and an outlet end 12.

Within the passageway, there is a valve seat indicated generally at 13. This seat comprises a rigid shoulder 14 defined by the brass body and an o-ring 15 of PTFE.

Abutting the o-ring 15 is a valve member in the form of a ball 16 having a passage 17 therethrough. The ball 16 is urged against the o-ring 15 by a compression spring 18. The compression spring 18 acts between a bearing member 19 of PTFE, and a brass spring seat 20.

The spring seat 20 is held in position in the passageway by a circlip 21.

In the position shown, with the passage 17 extending at right angles to the passageway through the body 10, the valve is in its closed position, with the ball 16 sealingly abutting the o-ring 15.

The ball 16 can however be turned through 900, to align the passage 17 with the valve passageway, and open the valve, by means of a square cross-section spigot 22 which engages in an appropriately shaped socket in the top of the ball 16.

The spigot 22 forms the lower part of a valve spindle 23.

The valve spindle 23 is rotatable in an upwardly extending bore 24 of the valve body. The spindle is retained in position by a circlip 25 and the bore 24 also contains graphite stem packing 26.

A square section operating head 27 is secured to the spindle 23 by a locking screw 28.

In use, the gas flows from right to left as viewed in the figure, and so the gas pressure is applied to the right hand side of the ball 16.

However, since this pressure is extremely low, it may not be sufficient in itself, to urge the ball 16 into sealing engagement with the o-ring 15. However, ample force is provided by the spring 18. The PTFE bearing member 19 enables the ball 16 to be turned relatively easily between the opened and closed position, in spite of the spring pressure.

Thus, the embodiment shown comprises a valve which seals efficiently even under very low pressures.

Indeed, the valve can be used under vacuum conditions.

The valve will of course operate very effectively at high pressures also. If there is high pressure on the right hand side of the valve, then this will assist the spring 18 in urging the ball 16 into sealing engagement with the o-ring 15.

The valve can be used as a bi-directional valve.

Provided that the strength of the spring 18 is selected accordingly, the spring is capable of providing effective sealing, even if a relatively high pressure is applied to the left hand side of the valve.

The valve is also fail safe in the event of a fire. High temperatures are likely to cause the o-ring 15 to melt, but if this happens, the spring 18 simply urges the ball 16 against the metal shoulder 14, bringing about a degree of re-sealing.

It will be appreciated that the connection between the spigot 22 and the ball 16 is such as to permit a degree of movement of the ball 16 longitudinally of the through passageway under the influence of the spring 18, and that, to this extent, the ball 16 can be regarded as free floating.

Alterations may be made to the disclosed embodiment without departing from the principal of the invention. For example the valve spindle design may be altered, the compression spring 18 might for example be replaced by disc springs, and the spring means may act directly on the ball 16 without the interposition of a bearing member such as 19. A specially designed annular rib or lip may be provided instead of the metal shoulder 14. The circlips could be replaced by threaded retainers.

In the embodiment shown, the manufacturing tolerances needed to achieve the required range of assembly conditions need not be stringent, since any excess play is taken up by the spring. Since the sealing force is largely dependent upon the spring, and is therefore reasonably consistent, the effort required to open and close the valve will also be reasonably consistent. The turning effort can therefore be reasonably accurately predicted and the valve can be designed so that the turning effort is reasonably low.

A further advantage is that any wear which takes place between the valve seat and the ball is automatically compensated for by the spring.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims (16)

1. A valve comprising a body defining a through passageway, a valve seat wlthin the passageway, a valve member abutting the valve seat, the valve member being rotatable from a closed position, to an open position in which fluid flow can take place along the passageway through a passage In the valve member, and spring means urging the valve member Into sealing engagement with the valve seat.

2. A valve as clalmed in Clalm 1, in which the spring means comprises a compression spring.

3. A valve as claimed In Clalm 1, in which the spring means comprises one or more disc springes.

4. A valve as claimed In any one of the preceding Claims, in which the valve seat comprises a first rigid seat portion and a second resilient seat portion, the valve member normally engaging the resilient portion but the degree of compression of the spring means being such that If the resi I lent portion melts or Is otherwise destroyed, the spring means is capable of moving the valve member into sealing engagement with the rigid seat portion.

5. A valve as claimed in Clalm 4, in which the first rigid seat portion is of metal and the second resilient seat portion Is of plastics material.

6. A valve as claimed In Clalm 4 or Claim 5, in which the first rigid seal portion is made of brass.

7. A valve as claimed In any one of Claims 4 to 6, in which the second resilient seal portion is made of PTFE.

8. A valve as claimed In any one of Claims 1 to 7, in which the degree of compression of the spring means is such as to seal the valve, in the closed position, regardless of which side of the valve Is the high pressure side.

9. A valve as claimed in any one of Claims 1 to 8, in which the valve member has a connection to means for rotating the valve member, the connection permitting at least limited movement of the valve member under the influence of the spring means.

10. A valve as clalmed in any one of the preceding Claims, In which the spring means abuts directly against the valve member.

11. A valve as clalmed In any one of Claims 1 to 9, in which there is a bearing member between the spring means and the valve member.

12. A valve as clalmed In Clalm 11, in which the bearing member is of plastics material.

13. A valve as clalmed In Clalm 12, In which the bearing member is of PTFE.

14. A valve as claimed in any one of the preceding Claims, In which the valve member comprises a ball member.

15. A valve as clalmed in any one of the preceding Claims, in which the spring means comprises a helical or coiled compression spring.

16. A valve constructed and arranged substantlally as herein described, with reference to the accompanying drawings.