GB1578969A - Emergency two-way shut-off valve - Google Patents

Description

(54) EMERGENCY TWO-WAY SHUT-OFF VALVE (71) We, D.S.B. VALVES LIMITED, a British Company, of 127-135 Merrylee Road, Glasgow G44 3DL, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to an emergency two-way shut-off valve.

According to the invention there is provided an emergency two-way shut-off valve comprising a housing and two valve members each one of which is movable apart from and towards the other valve member and spring-urged apart towards respective stops within the housing, the valve members having openings therethrough which, when the valve members are spaced apart, permit flow of fluid through the valve but, when the valve members are pressed together, are blocked off by imperforate portions of the valve members.

Thus, in the event of a pipeline failure downstream of the installed valve, the loss of back pressure on the downstream side of the upstream of the valve member causes a sufficient pressure differential to be set across the upstream valve member to result in the upstream valve member moving in a downstream direction off its stop against the spring bias into contact with the downstream valve member and thus block-off fluid forward flow through the valve.Conversely in the event of a pipeline failure upstream of the installed valve, the loss of forward pressure on the upstream side of the downstream valve member causes a sufficient pressure differential to be set up across the downstream valve member to result in the downstream valve member moving in an upstream direction off its stop against the spring bias into contact with the upstream valve member and thus block-off fluid back flow through the valve.

An embodiment of the invention will now be described by way of example, with reference to the accompanying drawings, in which: Fig. 1 is an axial section through an emergency two-way shut-off valve; and Fig. 2 is a view from line II-II in Fig. 1.

Referring to Figs. 1 and 2, an emergency two-way shut-off valve comprises a housing formed in two portions 1 and 2 each having at one end an annular flange 3, 4 from which a neck 5 6 reduces in its internal diameter from about double the internal diameter of the pipeline to the internal diameter of the pipeline at the other end 7, 8 where it can be connected to a pipe end.

Housing portion 1 has a hard steel ring 9 removably fitted about the opening in the face of the flange 3 while the neck 6 of the housing portion 2 has a cylindrical inner surface 10 extending from the face of the flange 4 to a hard steel ring 11 removably fitted within the neck 6.

When the two flanges 3, 4 are bolted or otherwise secured together, the two rings 9, 11 constitute stops for respective valve plates 12, 13 within the housing. Each valve plate 12, 13 is circular with a diameter such as to have a sliding fit within the surface 10. Each valve plate 12, 13 has three bored openings 14 of equal diameter and equally spaced apart. The total area of the three openings 14 in each valve plate 12, 13 is preferably slightly in excess of the cross-sectional area of the pipeline but the area of each opening 14 is less than area between adjacent openings 14 in each valve plate 12, 13. Also in each valve plate 12, 13 there is provided a central blind hole 15 providing a seat for each end of a compression spring 16 which urges the plates 12, 13 apart against their respective stop rings 9, 11.Means (not shown) may also be provided to stabilise the spring 16, such means may be telescoping sleeves or pins locating the ends of the spring 16 within the blind holes 15. It is necessary that when the valve plates are pressed together each opening 14 in each valve plate is blocked off by the area between adjacent openings 14 in the other valve plate. In order to provide this angular relationship between the valve plates 12, 13 two rib formations are disposed diametrically opposite each other on the circumferential surface of each valve plate 12, 13. These rib formations as shown in the form of an axially elongate protruding insert 17 slidable within correspondingly diametrically opposed axially elongate grooves 18.The actual disposition of.. the inserts 17 on the valve plate 12 is shewn in Fig. 2, the showing in Fig. 1 being merely for ease of illustration. Three large diameter O-rings 19 are set in annular grooves in the valve plates 12, 13 the valve plate 12 having one ring 19 on each side, one to seal against stop ring 9 and the other to seal against the valve plate 13, and the valve plate 13 having one ring 9 to seal against stop ring 11. Furthermore, three small diameter O-rings 20 circumscribe each opening 14 in the valve plate 12 at one side thereof to seal against the valve plate 13 in the areas between adjacent openings 14.

Under normal operating conditions the spring 16 keeps the valve plates 12, 13 apart so that gas or vapour can flow through the valve, via the openings 14 in the upstream valve plate, the space between the valve plates 12, 13 and the openings 14 in the downstream valve plate. Turbulence in the space between the valve plates 12, 13 also tends to keep the valve plates 12, 13 apart. In the event of a pipe failure downstream of the valve, the back pressure downstream of the valve will fall and this fall back pressure will be felt in the space between the valve plates 12, 13 so that pressure differential across the up stream valve plate will rise sufficiently to move the upstream valve plate in a downstream direction against the spring 16 into contact with the downstream valve plate and thus block-off gas or vapour forward flow through the valve.In the event of a pipe failure upstream of the valve, the forward pressure upstream of the valve will fall and this fall of forward pressure will be felt in the space between the valve plates 12, 13 so that the pressure differential across the downstream valve plate will rise sufficiently to move the downstream valve plate in an upstream direction against the spring 16 into contact with the upstream valve plate and thus block-off gas or vapour back flow through the valve.

The valve described and illustrated is designed primarily for use with air, other gas or steam at high or medium pressure. For use with liquids it is desirable to minimise turbulence in the space between the valve plates 12, 13 during normal operation. In such case the grooves 18 may be helical into which slidingly fit formations projecting from the circumference of both valve plates 12, 13. When the valve plates 12, 13 are fully apart the openings 14 in both valve plates are substantially in alignment with one another so that under normal operating conditions turbulence between the valve plates is minimised.However, due to the helical grooves, when one valve plate moves towards the other the moving valve plate also turns so that when contact is made between the valve plates 12, 13 the openings 14 in each valve plate are blocked off by the areas between adjacent openings 14 in the other valve plate. Prer ferably, the formations projecting from the circumference of both or one of the valve plates are helical ribs.

WHAT WE CLAIM IS: 1. An emergency two-way shut-off valve comprising a housing and two valve members each one of which is movable apart from and towards the other valve member and spring-urged apart towards respective stops within the housing, the valve members having openings therethrough which, when the valve members are spaced apart, permit flow of fluid through the valve but, when the valve members are pressed together, are blocked off by imperforate portions of the valve members.

2. An emergency two-way shut-off valve according to claim 1, in which the movement of each valve member relative to the other valve member is accompanied by a turning movement of the moving valve member so that when the valve members are fully spaced apart the openings therein are in substantial alignment.

3. An emergency two-way shut-off valve substantially as hereinbefore described with reference to the accompanying drawings.

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

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. openings 14 in the other valve plate. In order to provide this angular relationship between the valve plates 12, 13 two rib formations are disposed diametrically opposite each other on the circumferential surface of each valve plate 12, 13. These rib formations as shown in the form of an axially elongate protruding insert 17 slidable within correspondingly diametrically opposed axially elongate grooves 18. The actual disposition of.. the inserts 17 on the valve plate 12 is shewn in Fig. 2, the showing in Fig. 1 being merely for ease of illustration.Three large diameter O-rings 19 are set in annular grooves in the valve plates 12, 13 the valve plate 12 having one ring 19 on each side, one to seal against stop ring 9 and the other to seal against the valve plate 13, and the valve plate 13 having one ring 9 to seal against stop ring 11. Furthermore, three small diameter O-rings 20 circumscribe each opening 14 in the valve plate 12 at one side thereof to seal against the valve plate 13 in the areas between adjacent openings 14. Under normal operating conditions the spring 16 keeps the valve plates 12, 13 apart so that gas or vapour can flow through the valve, via the openings 14 in the upstream valve plate, the space between the valve plates 12, 13 and the openings 14 in the downstream valve plate. Turbulence in the space between the valve plates 12, 13 also tends to keep the valve plates 12, 13 apart. In the event of a pipe failure downstream of the valve, the back pressure downstream of the valve will fall and this fall back pressure will be felt in the space between the valve plates 12, 13 so that pressure differential across the up stream valve plate will rise sufficiently to move the upstream valve plate in a downstream direction against the spring 16 into contact with the downstream valve plate and thus block-off gas or vapour forward flow through the valve.In the event of a pipe failure upstream of the valve, the forward pressure upstream of the valve will fall and this fall of forward pressure will be felt in the space between the valve plates 12, 13 so that the pressure differential across the downstream valve plate will rise sufficiently to move the downstream valve plate in an upstream direction against the spring 16 into contact with the upstream valve plate and thus block-off gas or vapour back flow through the valve. The valve described and illustrated is designed primarily for use with air, other gas or steam at high or medium pressure. For use with liquids it is desirable to minimise turbulence in the space between the valve plates 12, 13 during normal operation. In such case the grooves 18 may be helical into which slidingly fit formations projecting from the circumference of both valve plates 12, 13. When the valve plates 12, 13 are fully apart the openings 14 in both valve plates are substantially in alignment with one another so that under normal operating conditions turbulence between the valve plates is minimised.However, due to the helical grooves, when one valve plate moves towards the other the moving valve plate also turns so that when contact is made between the valve plates 12, 13 the openings 14 in each valve plate are blocked off by the areas between adjacent openings 14 in the other valve plate. Prer ferably, the formations projecting from the circumference of both or one of the valve plates are helical ribs. WHAT WE CLAIM IS:

1. An emergency two-way shut-off valve comprising a housing and two valve members each one of which is movable apart from and towards the other valve member and spring-urged apart towards respective stops within the housing, the valve members having openings therethrough which, when the valve members are spaced apart, permit flow of fluid through the valve but, when the valve members are pressed together, are blocked off by imperforate portions of the valve members.

2. An emergency two-way shut-off valve according to claim 1, in which the movement of each valve member relative to the other valve member is accompanied by a turning movement of the moving valve member so that when the valve members are fully spaced apart the openings therein are in substantial alignment.

3. An emergency two-way shut-off valve substantially as hereinbefore described with reference to the accompanying drawings.