GB2230075A - Valve assembly - Google Patents

Abstract

A valve assembly has a valve housing (10), a valve actuating member (48) rotatably mounted with respect to the housing for actuating a valve closure member. A locking means is provided on one of the member (48) and housing (10) and, as shown, on the valve actuating member, and comprises locking members (72) engageable with recesses (76) in the other of the member (48) and valve housing when the actuating member is in a given angular position with respect to the valve housing. This permits the actuating member to be locked in a fixed position, thus preventing unauthorised operation of the valve. It also allows an authorised person to check that the valve is in its correct position, since the valve actuating member will not rotate, it can be assumed that the valve is locked in its correct position. The valve assembly can be actuated without unlocking of the unlocking means by removal of locking screw (84) and relative rotation of housing parts (17, 46). <IMAGE>

Description

DESCRIPTION VALVE ASSEMBLY The present invention relates to valve assemblies, and in particular to valve assemblies in which a valve closure member may be locked in a fixed position.

In many industrial installations, for example oil refineries, there are valves whose correct adjustment is necessary for the efficient and safe operation of the installation. Adjustment of these valves is sometimes necessary, but should only be undertaken by authorised personnel.

One way of achieving this is to provide each valve with a removable actuating handle, which is removed once the adjustment has taken place. By arranging the interfitting portions of the valves and the handles, each handle can only be used to actuate one particular valve, or one particular type of valve. Normally, the handles are stored safely when not in use, and it is necessary for an authorised person to log out each handle which is required. Thus, the likelihood of accidental incorrect operation of a valve by an authorised person is reduced, since when logging out the required handle, he must state which valve he wishes to operate, and that handle will not be able to operate any other valve. Moreover, the restricted access to the handles reduces the likelihood of operation of the valves by an unauthorised person.

The above arrangement suffers from three disadvantages. Firstly, although the handles are available only to authorised personnel, it is conceivable that the valves might be operable without the handles, for example by means of wrenches or the like, which would permit unauthorised operation of the valves. Secondly, the valves themselves are not lockable in a fixed setting, thus making it possible for an authorised person to leave a valve inadvertently in an incorrect state. Thirdly, the handles themselves are bulky, making them difficult to carry, and taking up a large amount of storage space.

It is an object of the present invention to provide a valve assembly which aims to overcome the above disadvantages.

In accordance with the present invention, a valve assembly comprises a valve housing, a valve actuating member rotatably mounted with respect to the housing for actuating a valve closure member, and locking means on one of the actuating member and the valve housing, comprising a locking member engageable with a recess in the other of the actuating member and the valve housing when the actuating member is in a given position with respect to the valve housing.

Such an arrangement has the advantage that the valve actuating member can be locked in a fixed position, thus preventing unauthorised operation of the valve. It also allows an authorised person to check that the valve is in its correct position on leaving the valve, since if the valve actuating member will not rotate, it can be assumed that the valve is locked in its correct position.

Preferably, the locking means is key-actuated, which makes it convenient for an operator and which also cuts down on storage space. In the preferred embodiment, the key is insertable into, and removable from, the locking means only when the locking member is engaged with the recess. This ensures that the key can only be removed when the valve is locked in the correct position.

It is preferable for the valve actuating member to be screw-threadedly mounted with respect to the housing. This makes it necessary for the actuating member to be in the correct rotational position and the correct axial position in order for the locking means to be actuated, and is particularly useful when the valve actuating member is rotatable through more than one full rotation.

The locking means may be conveniently mounted on the valve actuating member, the recess thus being in the valve housing. There may be more than one locking member and/or recess provided.

There may be means for altering the opening of the valve without inducing relative rotation between the valve housing and the valve actuating member. This may be achieved by providing the valve housing in a two-part arrangement, the two parts being rotatable relative to one another but releasably secured in a fixed angular relation. This allows one of the portions of the valve housing to rotate with the valve actuating member to alter the opening of the valve without changing the relative positions of the locking member and recess.

The present invention includes a valve assembly comprising a two-part valve housing, the two parts being relatively rotatable and releasably securable in a fixed angular relation, a valve actuating member screw-threadedly mounted with respect to one part of the valve housing for actuating a valve closure member, and locking means mounted on the valve actuating member and rotatable therewith, the locking means comprising a locking member engageable with a recess in the valve housing when the valve actuating member is in a given position with respect to the said one portion of the valve housing.

By way of example only, a specific embodiment of the present invention will now be described, with reference to the accompanying drawings, in which: Fig.l is an exploded perspective view of a valve fitted with an embodiment of valve control means in accordance with the present invention; and Fig.2 is a longitudinal cross-section through the assembled valve of Fig.l.

A valve comprises a valve body 10 which is releasably secured in a cavity 12 of a valve block 14 by means of screw-threaded connections 16 on the walls of the aperture and at one end of a base portion 17 of the valve body. Concentrically-disposed annular seals 18,20 are located in between the valve body and the valve block. The operation of the valve is generally conventional, and will thus only be described briefly.

The valve is provided with an elongate valve closure member 22 having a frusto-conical valve head 24. The valve closure member is contrained to move along its longitudinal axis by means of a cylindrical portion 25 of the valve closure member which is disposed between the valve head 24 and the remainder of the valve closure member, and which is slidably engaged with a cylindrical passageway 28 in the base portion 17 of the valve body, and by the stem of the valve closure member which also slidably engages with a neck 30 in the base portion 17. Two packing glands 32,34 bear upon the neck 30 and against the stem, and are held in position axially by means of a cup-shaped bearing member 36 whose outer-cylindrical wall is threaded and received in a correspondingly threaded portion of the base portion 17.

The end of the valve closure member remote from the valve head 24 is provided with an enlarged head 38. A cylindrical force transmission member 40 passes through, and is screw-threadedly engaged with an aperture in the base of the cup-shaped bearing member 36. One end of the force transmission member 40 bears against the head 38 of the valve closure member, and an arcuate extension 42 of the force transmission member hooks under the head 38 of the valve closure member. By varying the axial position of the force transmission member, the valve closure member may be pushed into, or drawn out of, engagement with a valve seat 44 in the valve block 14.

The valve body also comprises an upper, outwardly cylindrical, portion 46, secured to the lower portion 17. An actuator comprising a star-shaped operating wheel 48 and a driving member 50 secured to the wheel are fitted into the upper end of the portion 46. The exterior of the driving member 50 is threaded, and engages with corresponding threads in an internal neck portion 52 of the cylindrical upper portion 46. The driving member is provided with a square cross-section through aperture 54, and receives the squared end 56 of the force transmission member 40.

Thus, as the operating wheel is rotated, the force transmission member 40 is rotated about its longitudinal axis. The threaded engagement of the force transmission member with the cup-shaped member 36 causes the force transmission member to move along its elongate axis, thereby moving the valve closure member 22 towards or away from engagement with the valve seat 44, depending upon the direction of rotation of the wheel 48. Thus, by rotating the wheel 48, the opening and controlling of the valve may be controlled.

The above description is conventional, but the illustrated embodiment of the present invention has a number of further features. The actuator comprises the star-shaped operating wheel 48 which is attached to a lock receiving sleeve 58 by means of four retaining screws 60. The wheel 48 and the receiving sleeve 58 are provided with aligned, through, cylindrical apertures 62,64, thereby forming a cavity in which a KABA K200 deadlock 65 fits. This is a commercially-available one-position opening lock which comprises an outer barrel 66, an inner barrel 68 and a slot 70 for receiving a key to allow the operation of the lock to take place by relative rotation of the inner and outer lock barrels 68,66.The lock is such that it has two positions, a first position in which two diametrically opposed locking lugs 72 are withdrawn into the lock (as shown in full lines in Fig.2) and a second position in which the lugs extend from the lock (as shown in chain dot in Fig.2).

Moreover, the key may only be inserted into, and removable from the slot 70 when in the second of the above-mentioned positions. It can be seen from Fig.2 that the lock is secured to the driving member 50 by means of four screws 74, so that the handle 48, the lock receiving sleeve 58, the lock and the driving member 50 are constrained to move together.

It can be seen from Fig.2 that the upper edge of the upper portion 46 of the valve body is provided with two, diametrically opposed recesses 76, and that the exterior surface of the upper end of the upper portion 46 is screw threaded, having the same pitch as the screw threaded connection between the members 50, 52. A capping sleeve 78 is placed on top of the upper portion 46 and comprises a first portion 78a which engages screw threadedly with the threaded portion of the upper portion 46 of the valve body, and a second portion 78b having an internal diameter equal to the internal diameter of the valve body, the two portions being joined by an internal annular shoulder 80. The sleeve sits atop the valve body, with its internal shoulder 80 resting on the upper edge of the valve body.The recesses 76 in combination with the shoulder 80 of the sleeve thus form diametrically opposed slots, the depth and width of which is chosen to receive the extended lugs 72 of the lock.

The opposite end of the upper portion 46 of the valve body is provided with a further cylindrical sleeve 82 which is secured to the lower portion 17 of the valve body by means of set screws (not shown).

The upper and lower portions 46,17 of the valve body are normally prevented from relative rotation by means of a countersunk head locking screw 84, which passes through the sleeve 82 (which is attached to the lower portion 17) and the wall of the upper portion 46.

In normal use, the lugs 72 of the lock 65 engage in the slots formed by the recesses 76, thus preventing rotation of the wheel 48 and preventing adjustment of the valve. Adjustment of the valve may only be effected by inserting the key into the slot 70 of the lock 65 and turning the key to the alternative position, thereby withdrawing the locking lugs 72 from the slots into the lock 65, which thus allows the hand wheel 48 to be rotated and the valve to be adjusted.

However, it will be noted that rotation of the hand wheel 48 also causes movement along the rotational axis, as a result of the threaded connection between the driving member 50 and the internal shoulder 52 of the upper portion 46 of the valve body and between the capping sleeve 78 and the upper end of the upper portion 46. Thus, any attempt to lock the wheel 48 in any position other than its original position will be impossible. The pitch of the said threaded engagement is chosen so that a half turn of the wheel 48 will induce sufficient axial movement of the lugs 72 to prevent their re-engagement in the opposite slots.

Further axial movement, of course, produces even more misalignment. Moreover, since the key may only be removed when the lock is in its locked condition, an operator will be unlikely to forget inadvertently that the valve has not been locked in its set position, since the key will still be in the lock and cannot be withdrawn.

If it is desired to alter the set position of the valve, then this can be done by removing the locking screw 84.

Removal of the screw 84 allows the upper portion of the valve body to rotate with the wheel 48, or allows rotation of the upper portion of the valve body while the wheel 48 remains stationary with respect to the lower portion 17, thus permitting adjustment of the opening of the valve without altering the relative positions of the slots and the lugs 72. When the desired valve opening is obtained, the upper portion is rotated to allow the locking screw 84 to be re-inserted in the aligned apertures in the upper and lower portions 46,17, and the lock 65 may then be actuated to extend the lugs 72 and thereby engage them in the receiving slots, thus locking the valve in the desired position.

As an alternative to the above, it would be possible to have the locking member as the valve body, having a lug which is engageable with a recess in the wheel 48 or some other member attached to the wheel 48.

The invention is not restricted to the details of the foregoing embodiment.

Claims (1)

1. A valve assembly comprising a valve housing, a valve actuating member rotatably mounted with respect to the housing for actuating a valve closure member, and locking means on one of the actuating member and the valve housing, comprising a locking member engageable with a recess in the other of the actuating member and the valve housing when the actuating member is in a given position with respect to the valve housing.

2. A valve assembly as claimed in claim 1, wherein the valve actuating member is screw-threadedly mounted with respect to the housing.

3. A valve assembly as claimed in claim 2, wherein the valve actuating member is rotatable through more than one full rotation.

4. A valve assembly as claimed in any of the preceding claims, wherein the locking means is mounted on the valve actuating member and the recess is in the valve housing.

5. A valve assembly as claimed in claim 4, comprising a plurality of locking members and/or recesses.

7. A valve assembly as claimed in any of the preceding claims, wherein the locking means is keyactuated.

8. A valve assembly as claimed in claim 7, wherein the key is insertable into, and removable from, the locking means only when the locking member is engaged with the recess.

9. A valve assembly as claimed in any of the preceding claims, comprising means for altering the opening of the valve without inducing relative rotation between the valve housing and the valve actuating member.

10. A valve assembly as claimed in claim 9, wherein the means for altering the opening of the valve comprises a valve housing with two parts rotatable relative to one another and means for releasably securing the two parts in a fixed angular relation.

11. A valve assembly as claimed in any of the preceding claims, comprising a valve closure member which is slidably disposed within the valve body.

12. A valve assembly as claimed in claim il, wherein the valve closure member is provided with a head which is engageable with a valve seat.

13. A valve assembly comprising a two-part valve housing, the two parts being relatively rotatable and releasably securable in a fixed angular relation, a valve actuating member screw-threadedly mounted with respect to one part of the valve housing for actuating a valve closure member, and locking means mounted on the valve actuating member and rotatable therewith the locking means comprising a locking member engageable with a recess in the valve housing when the valve actuating member is in a given position with respect to the said one portion of the valve housing.

14. A valve assembly substantially as herein described, with reference to, and as illustrated in, the accompanying drawings.