GB2031121A - Gate valves - Google Patents

Abstract

A non-rising stem gate valve includes an externally threaded extension member 3 mounted at one end on the stub 1 of the valve stem; a frame 12 mounted on the valve housing 2 and including an internally threaded locking member 13 engaging with the valve stem extension member 3; and a valve handle 7 coupled with the free end of the extension member 3; the locking member 13 being movable along the extension member 3 during operation of the valve by interengagement of the respective threads such as to fit about the coupling between the handle 7 and the extension member 3 to provide interlocking therebetween unless the valve has been rotated by the handle to an open valve position. <IMAGE>

Description

SPECIFICATION Improvements in or relating to gate valves This invention relates to gate valves of a nonrising stem variety. Such valves have the characteristic that linear movement of the gate and its associated support or supports is confined within the outer casing of the valve, actuation of the valve being by rotation of the stub of the valve stem which protrudes from the valve housing.

Such valves are commonly used in below ground fire protection water mains pipelines.

In applications of this kind it is imperative that the operating handle for the valve be permanently available for operation of the valve when the valve is in a closed position.

It is an object of the present invention to provide a non-rising stem valve meeting this requirement.

According to the invention there is provided a non-rising stem gate valve including an externally threaded extension member mounted at one end on the stub of the valve stem; a frame mounted on the valve housing and including an internally threaded locking member engaging with the valve stem extension member; and a valve handle coupled with the free end of the extension member; the locking member being moveable along the extension member during operation of the valve by interengagement of the respective threads such as to fit about the coupling between the handle and the extension member to provide interlocking therebetween unless the valve has been rotated by the handle to an open valve position.

By means of the invention it is ensured that the handle for operating the valve is retained in association with the valve unless the valve is in an open position so that there is no risk of being unable to open the valve because of the absence of the operating handle.

In order that the invention may be more readily understood one embodiment thereof will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is an elevation of part of a nonrising stem gate valve according to the invention; and Figure 2 is a more detailed elevation of a portion of the valve shown in Fig. 1.

As can be seen from the drawings the stub 1 of the valve stem extends from the valve housing 2 in the normal manner.

An externally threaded extension rod 3 is attached to the stub 1 by means of a yoke 4 carrying a cup 5 having a grub screw 6 passing through its side into engagement with the stub 1.

A valve operating handle 7 is coupled to the rod 3 by means of a lug 8 fitting within a slot 9 extending across a head portion 10 of the rod 3.

Mounted upon the valve housing 2 around the stub 1 by means of bolted brackets 11 is a frame 1 2. Disposed within the frame 1 2 is a sleeve 1 3 which carries at its lower end a threaded nut 1 4 engaging with the threaded rod 3. The sleeve 1 3 is prevented by the frame from rotation but is capable of movement axially upon rotation of the threaded rod 3 within nut 13 upon actuation of the valve.

At the position shown in Fig. 2, the valve handle has been rotated to provide a fully open valve position. In this position the sleeve 1 3 is at its lowest position on the rod 3 so that the handle 7 is capable of disengagement from the rod 3 by sliding the lug 8 from the slot 9 for maintenance and/or replacement.

As is shown in Fig. 1, in all other conditions of the valve, the sleeve 1 3 is above its lowest position and fits around the connection between the handle 7 and the rod 3 thereby preventing disengagement.

1. A non-rising stem gate valve including an externally threaded extension member mounted at one end on the stub of the valve stem; a frame mounted on the valve housing and including an internally threaded locking member engaging with the valve stem extension member; and a valve handle coupled with the free end of the extension member; the locking member being movable along the extension member during operation of the valve by interengagement of the respective threads such as to fit about the coupling between the handle and the extension member to provide interlocking therebetween unless the valve has been rotated by the handle to an open valve position.

2. A gate valve according to Claim 1 wherein the locking member is movable along the extension member during operation of the valve so as to provide interlocking between the handle and the extension member unless the valve has been rotated to a fully open position.

3. A gate valve according to Claim 1 or 2 wherein the valve handle is coupled to the extension member by means of a transverse lug portion of the handle engaging in a transverse slot in the extension member.

4. A gate valve according to anyone of the preceding claims wherein the locking member comprises a sleeve having a nut disposed within it to provide the internal threading of the locking member.

5. A gate valve substantially as shown in and as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to gate valves This invention relates to gate valves of a nonrising stem variety. Such valves have the characteristic that linear movement of the gate and its associated support or supports is confined within the outer casing of the valve, actuation of the valve being by rotation of the stub of the valve stem which protrudes from the valve housing. Such valves are commonly used in below ground fire protection water mains pipelines. In applications of this kind it is imperative that the operating handle for the valve be permanently available for operation of the valve when the valve is in a closed position. It is an object of the present invention to provide a non-rising stem valve meeting this requirement. According to the invention there is provided a non-rising stem gate valve including an externally threaded extension member mounted at one end on the stub of the valve stem; a frame mounted on the valve housing and including an internally threaded locking member engaging with the valve stem extension member; and a valve handle coupled with the free end of the extension member; the locking member being moveable along the extension member during operation of the valve by interengagement of the respective threads such as to fit about the coupling between the handle and the extension member to provide interlocking therebetween unless the valve has been rotated by the handle to an open valve position. By means of the invention it is ensured that the handle for operating the valve is retained in association with the valve unless the valve is in an open position so that there is no risk of being unable to open the valve because of the absence of the operating handle. In order that the invention may be more readily understood one embodiment thereof will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is an elevation of part of a nonrising stem gate valve according to the invention; and Figure 2 is a more detailed elevation of a portion of the valve shown in Fig. 1. As can be seen from the drawings the stub 1 of the valve stem extends from the valve housing 2 in the normal manner. An externally threaded extension rod 3 is attached to the stub 1 by means of a yoke 4 carrying a cup 5 having a grub screw 6 passing through its side into engagement with the stub 1. A valve operating handle 7 is coupled to the rod 3 by means of a lug 8 fitting within a slot 9 extending across a head portion 10 of the rod 3. Mounted upon the valve housing 2 around the stub 1 by means of bolted brackets 11 is a frame 1 2. Disposed within the frame 1 2 is a sleeve 1 3 which carries at its lower end a threaded nut 1 4 engaging with the threaded rod 3. The sleeve 1 3 is prevented by the frame from rotation but is capable of movement axially upon rotation of the threaded rod 3 within nut 13 upon actuation of the valve. At the position shown in Fig. 2, the valve handle has been rotated to provide a fully open valve position. In this position the sleeve 1 3 is at its lowest position on the rod 3 so that the handle 7 is capable of disengagement from the rod 3 by sliding the lug 8 from the slot 9 for maintenance and/or replacement. As is shown in Fig. 1, in all other conditions of the valve, the sleeve 1 3 is above its lowest position and fits around the connection between the handle 7 and the rod 3 thereby preventing disengagement. CLAIMS

1. A non-rising stem gate valve including an externally threaded extension member mounted at one end on the stub of the valve stem; a frame mounted on the valve housing and including an internally threaded locking member engaging with the valve stem extension member; and a valve handle coupled with the free end of the extension member; the locking member being movable along the extension member during operation of the valve by interengagement of the respective threads such as to fit about the coupling between the handle and the extension member to provide interlocking therebetween unless the valve has been rotated by the handle to an open valve position.

2. A gate valve according to Claim 1 wherein the locking member is movable along the extension member during operation of the valve so as to provide interlocking between the handle and the extension member unless the valve has been rotated to a fully open position.

3. A gate valve according to Claim 1 or 2 wherein the valve handle is coupled to the extension member by means of a transverse lug portion of the handle engaging in a transverse slot in the extension member.

4. A gate valve according to anyone of the preceding claims wherein the locking member comprises a sleeve having a nut disposed within it to provide the internal threading of the locking member.

5. A gate valve substantially as shown in and as hereinbefore described with reference to the accompanying drawings.