GB2121929A - Valve lock - Google Patents

Abstract

A valve lock has two parts 13, 15 hinged 4 and lockable 16, 17 together to form a container enclosing a valve handwheel H. The valve spindle S is a freely-rotatable fit in a spigot 11 on the spindle S and welded to one part 13. When the valve lock is closed, it can be spun on the spindle S but the handwheel can not be grasped to operate the valve. <IMAGE>

Description

SPECIFICATION Valve lock The present invention relates to a lock for a handwheel operated valve.

In many industrial and commercial undertakings using pipelines carrying solids, liquids, gases and mixtures thereof, there are valves in the pipelines for controlling and diverting flow, as required, including for the protection of other machinery. It is obviously of great importance that such valves are not operated by unauthorised personnel. This may be achieved by locking of the valve so that only the authorised holder of an appropriate key can operate the handwheel of the valve.

A known type of valve has a special casing which is adapted for the handwheel to be locked.

However, having a special casing, this valve is expensive. Furthermore, if it becomes necessary, due to increased security awareness to render an existing ordinary valve lockable, this can only be done by replacing the ordinary valve with the special valve. This is likely to be an inconvenient operation.

The present invention has been conceived with a view to enabling existing valves to be locked.

A valve lock according to the invention comprises a first part rotatably mounted on a valve-handwheel spindle, with the spindle passing through the first part, a second part complementary to the first part for forming a container enclosing the handwheel of the valve, and lockable means for securing the second part of the first part in their respective positions enclosing the handwheel.

In a simple arrangement, the lockable means may comprise a staple on the first part to which a hasp on the second part is lockable with a padlock. However it is preferred that the lockable means comprises a lock contained within the container and actuable with a key from outside the container. Such an arrangement is less susceptible to being tampered with than the simpler padlocked arrangement.

The lock may be of the type which is springloaded and automatically locks on closure of the container. Alternatively it may be of the type which must be locked with its key and is preferably such that its key is only released when actually locked.

Conveniently, the first part has an apertured spigot and the two parts are hinged together, although the two parts could be adapted to clip together in such a manner that they are firmly connected when the container is closed yet can be parted when the container is open.

To help understanding of the invention two specific embodiments thereof will now be described with reference to the accompanying drawings, in which: Figure 1 is a central cross-sectional view of one valve lock of the invention, Figure 2 is a front elevational view of a second valve lock of the invention, and Figure 3 is a view similar to that of Figure 1, taken on line Ill-Ill of Figure 2, of the second valve lock.

Referring first to Figure 1, a steel spigot 1, having a central bore 2, is welded to a circular steel back plate 3, which also has a central aperture in alignment with the bore 2. In use a valve handwheel spindle S can pass through the bore 2 and the aligned aperture with the handwheel H on lhe side remote from the spigot 1, as shown. A hinge 4 is attached to the back plate at its periphery and is also attached to a steel front plate 5, the axis of the hinge extending tangentially of the plates' periphery. The front plate is dished to accommodate the handwheel H.

When as shown the front plate 5 is swung about the hinge 4 against the back plate 3, the plates form an enclosed container within which the handwheel is contained. The spigot 1 and back plate 3 are free to turn on the valve spindle S, whereby spinning of the closed container will not turn the handwheel.

A key-freed lock 6 is fitted to the upstand of the front plate 5 opposite the hinge 4 and an apertured bracket 7 is fixed to the back plate 3 in such a position that a bolt 8 of the lock 6 can engage in the aperture 9 of the bracket. The bolt 8 is spring-loaded and has an angled face 10 whereby on closure of the front plate 5 to the back plate 3 the bolt 8 is pushed into the lock 6 by the bracket 7 and then springs into the aperture 9.

Figure 2 and 3 show a second valve lock according to the invention. This valve lock also has an apertured steel spigot 11 welded to a steel plate 13 which has a small lip 13'. The front plate 1 5 has an upstand 15', which engages inside the lip 13' of the back plate. The plates are hinged together at 14. A lock 1 6 of the type whose key is released only when it is locked, is attached within the upstand 15' with only its key slot 16' on the outside of the upstand 1 5'. A bracket 1 7 is spotwelded to the inside of the back plate 13 in such position that a locking tongue 1 8 of the lock 1 6 can engage thereunder when the lock is locked.

Both the above described valve locks can be fitted to conventional valves, provided their handwheels H and spindles S are of an appropriate size, by release of the handwheel nuts N, withdrawal of the handwheels H from the spindles S, sliding of the spigots 1, 11 onto the spindles S and replacement of the handwheels H and nuts N. The valve locks are then secured to their valves.

According to the size of the valve locks, the steel plates may vary from 14 to 20 swg, typically being 16 swg for an 8" or 10 2 (200 or 270 mm) internal diameter valve lock.

The invention is not intended to be restricted to the details of the above described valve locks. For instance the lock 6 of the Figure 1 valve lock could be replaced by a padlock passing through a pair of holes close to the periphery of the plates 3, 5. The hinge 14 of the Figure 2 lock could be placed within the upstand 15' and rim 13' for increased security.

Claims (9)

1. A valve lock comprising a first part rotatably mountable on a valvehandwheel spindle, with the spindle passing through the first part, a second part complementary to the first part for forming a container enclosing the handwheel of the valve, and lockable means for securing the second part to the first part in their respective positions enclosing the handwheel.

2. A valve lock as claimed in claim 1 wherein the first part has an apertured spigot attached thereto through which the valve spindle passes.

3. A valve lock as claimed in claim 1 or claim 2 wherein the lockable securing means includes a hinge connecting the first and second parts.

4. A valve lock as claimed in claim 1, claim 2 or claim 3 wherein the first part is flat back plate and the second part is dished to provide space for the handwheel.

5. A valve lock ds claimed in claim 1, claim 2, or claim 3 wherein the first part is a flat back plate with a lip and the second part is dished with an upstand to provide space for the handwheel and the upstand fits within the lip of the second part.

6. A valve lock as claimed in any preceding claim wherein the lockable securing means includes a spring loaded lock automatically locking the two parts together when they are moved to their respective positions enclosing the handwheel, the lock being attached to one of the parts and engaging a member attached to the other of the two parts.

7. A valve lock as claimed in any of claims 1 to 5 wherein the lockable securing means includes a lock of the type that releases its key only when locked, the lock being arranged to lock the two parts together when they are moved to their respective positions enclosing the handwheel, the lock being attached to one of the parts and engaging a member attached to the other of the two parts.

8. A valve lock as claimed in claim 6 or claim 7 wherein the lock is contained within the container when closed, whilst being actuable with a key from outside the container.

9. A valve lock substantially as hereinbefore described with reference to Figure 1 or Figures 2 and 3, the accompanying drawings.