GB2057639A - Shut-off valve - Google Patents

Abstract

A shut-off valve having the combined functions of emergency manual control and normal remote control for shutting the valve off. The valve has a closure member 11 which is spring or weight loaded down onto a valve seat 13 and is mounted on a rod 8 to which a ferromagnetic plate 10 is attached. A magnetic coupling system 18 comprising a permanent-magnet and an electromagnet is movable by a lever 17 outside the housing to move the permanent-magnet into engagement with the ferromagnetic plate and then withdraw the plate so that the closure member is lifted off the valve seat. Energisation of the electromagnet reduces the magnetic attraction between the permanent- magnet and the plate causing the closure member to engage the valve seat under the force exerted by the spring or weight loading. The closure member may also be moved into the closed position by the lever moving both the permanent-magnet and the plate. <IMAGE>

Description

SPECIFICATION Shut-off valve This invention relates to shut-off valves.

Pipelines carrying liquids which are a source of danger to the environment usually have to be provided with safety or emergency valves to prevent the liquids from flowing into a danger zone in the event of fire, floods, or earthquakes. In valves of this kind, the energy required to close the valve is usually stored in the form of a tensioned spring or a lifting weight, and emergency shut-off is effected manually simply by actuation of a smooth-running rocking, pivoting or rotary lever.

These valves do not have a remote-control release since the control line required cannot be expected to be either intact or present in the event of an emergency.

Regular maintenance and inspection of serviceability of emergency valves is often neglected. It has been found that plant operators carry out only the checks required to maintain normal operation of the plant and usually neglect periodic checking of purely emergency devices, more particularly relying on immediate emergency aid from the fire service etc., while in extreme cases even the existence of such emergency devices is completely overlooked.

The invention has as its object to obviate this disadvantage. The invention accordingly relates to an emergency shut-off valve having a springloaded or weight-loaded valve closure member adapted to be manually lifted from the valve seat by an actuating means against the loading of the spring or weight in order to open the valve.

In accordance with this invention therefore we provide a shut-off valve comprising a valve seat, a spring or weight-loaded closure member engageable with said seat, actuating means to lift the closure member off said seat against the force of said spring or weight loading, and coupling means having a permanent magnet to magnetically couple together said actuating means and said closure member and an electromagnet to break said magnetic coupling to enable the closure member to engage the valve seat by the force exerted by said spring or weight loading.

Such an emergency valve combines the function of a manually actuated emergency valve and of a control valve releasable by remotecontrol. This combination of two valve functions in one valve enables the emergency valve to be used as a normal-service control valve provided in practically all pipelines, so that it automatically forms part of those sections of the plant which must in any case be subjected to routine checks to maintain normal operation, thus ensuring regular checks on both the normal and emergency functions of the valve. The combined emergency and control valve also does away with the need for the series connection of an emergency valve and a separate control valve otherwise conventional in such cases. The control valve can thus be omitted.

Preferred embodiments of the invention are explained in detail hereinafter with reference to the accompanying drawings, wherein: Figure 1 is a section through a first embodiment of a valve according to this invention in the open position; Figure 2 is a section through the same valve shown in Figure 1 in the closed position; Figure 3 is a section through a second embodiment of a valve according to this invention in the open position; and Figure 4 is a side elevation of the valve of Figure 3 in the closed position.

The valve shown in Figures 1 and 2 comprises a T-piece 1 which forms the actuai valve housing, and a magnet housing 2 secured thereto and containing a release mechanism, which will be described hereinafter.

The magnet housing 2 comprises a bottom part 3 with a screw-threaded end 4 which is screwed into the top end 5 of the T-piece 1. The other two ends 6 and 7 of the T-piece 1, which are at right angles to one another, are used to connect the valve to a pipeline system (not shown).

A rod is slidable in the bottom part 3 of the magnet housing 2 coaxially of the two aligned ends 5 and 6 of the T-piece 1 and is sealed off by means of a sealing ring 9. A ferromagnetic plate 10 is fixed to the top end of the rod 8 situated inside the magnet housing. The bottom end of the rod bears, or is constructed in the form of, a valve closure member.

In this example, the closure member is formed by a disc 11 provided with a sealing ring 12.

A conical valve seat 1 3 is formed in the end 6 of the T-piece 1 and together with the closure member 11-12 at the end of the rod 8 forms the means of shutting off or allowing the flow of medium through the ends 6 and 7 of the T-piece 1. A coil spring 14 encircling the rod 8 presses the closure member 11-12 against the valve seat 13 in the closed state (Figure 2).

The end of the magnet housing 2 remote from the base part 3 has a bushing 15 in which an actuating rod 1 6 is slidable coaxially of the rod 8.

The top end of rod 1 6 carries a handle 17, while on the bottom end inside the housing 2 a latching permanent-electromagnet 1 8 is mounted. Leads 1 9 for the electromagnet 1 8 are taken out through a cable bushing 20 disposed on the side of the housing 2.

The magnetic latching system 1 8 comprises a permanent-magnet having a downwardly open shell core and an energisation coil which, when live, neutralises the magnetic field produced by the permanent-magnet at the latching surface.

Latching magnets of this kind are marketed, for example, by Messrs. Binder Magnete GmbH, Villingen-Schwenningen, Federal Republic of Germany, under the designation 01 320 03-1 5B.

The emergency valve described operates as follows: Starting from the closed state of the valve shown in Figure 2, actuating rod 1 6 is turned anticlockwise through approximately one-quarter revolution by means of handle 17, a pin 21 disposed on the side of the rod 16 being disengaged from a shoulder 22 of the bushing 1 5 and coming to a position above a slot 23 in the bushing 15, said slot being parallel to the rod axis.

Rod 16 is then pushed or dropped into the magnet housing 2 until the permanent-magnet of the magnetic system 18, which is devoid of current, engages and holds plate 10 fast. Rod 1 6 is then raised or pulled out of the housing 2, the closure member 11-12 being lifted from the seat 13 in opposition to the force of the return spring 14 because of the permanent-magnetic coupling between the magnetic system 1 8 and the plate 10, so that the valve is opened (Figure 1). The handle 17 is then turned clockwise until pin 21 engages shoulder 22 of the bushing 1 5 and fixes the actuating rod 1 6 and hence the valve in the open position.

If an electrical release pulse is now fed to magnetic system 1 8 via lead 19, the latching force of the permanent-magnet is temporarily compensated or reduced by the electromagnetic field of the energisation coil and the rod 8 together with the closure member 11-12 drops back into the valve seat 13 in response to the action of the return spring 14, so that the valve is closed.

Advantageously, the construction of the magnet housing 2 is such that the sealing ring 9, and the rod 8 bearing the closure member 11-12, are protected from dirt and dust. This ensures that rod 8 always remains readily movable to enable the valve to be closed electrically.

Another advantage of the parts associated with the closure member 11-12 being fully encased is that these parts are not accessible from the exterior and cannot therefore be jammed.

Figures 3 and 4 show a second embodiment of a safety valve without the T-piece 1 according to the invention. This differs from the construction shown in Figures 1 and 2 only in respect of a somewhat different external shape of the magnet housing and by a different shape of actuating handle. All the other parts are identical and therefore have the same reference as in Figures 1 and 2. These figures do not show the T-piece forming the valve housing.

Except for the base 3, the housing 2' is a casting made in one piece. Base 3 is fixed in housing 2' by means of a cap nut 3a. The bushing 1 5' at the top of the housing has also been shifted to the interior thereof. It continues out in the form of two segmental lugs 24a and 24b.

The rigid handle 1 7 of Figures 1 and 2 is in this embodiment replaced by a U-shaped two-armed rocking lever 17' to move the rod 1 6. Rocking lever 17' is mounted on rod 16 so as to pivot about an axis 17" at right angles to the rod axis.

Shaft 1 6 is raised or lowered simply by swinging the rocking lever through 900 to either of the positions shown in Figures 3 and 4, thus manually opening or closing the valve.

In both embodiments the spring 14 may be omitted and the plate 10 weighted to ensure that the closure member drops rapidly and seats firmly on the valve seat 13 to close off the valve either on energisation of the magnetic system 1 8 or on downward movement of the rod 16 effected by handle 17 or rocking lever 17'.

Claims (9)

1. A shut-off valve comprising a valve seat, a spring or weight loaded closure member engageable with said seat, actuating means to lift the closure member off said seat against the force of said spring or weight loading, and coupling means having a permanent-magnet to magnetically couple together said actuating means and said closure member and an electromagnet to break said magnetic coupling to enable the closure member to engage the valve seat by the force exerted by said spring or weight loading.

2. A shut-off valve as claimed in Claim 1 including a housing having a base through which extends a first rod in sealing-tight engagement therewith, that end of said rod extending from said housing having mounted thereon said closure member and the opposite end having secured thereto a ferromagnetic plate within said housing and movable therein with said first rod; said actuating means including a second rod which extends into said housing in alignment with said first rod and carries said permanent and electromagnets.

3. A shut-off valve as claimed in Claim 2 including a manually operable lever coupled to said second rod to move said coupling means into magnetic engagement with said closure member when the latter is engaged with said valve seat and then lift said closure member off said valve seat.

4. A shut-off valve as claimed in Claim 3 including locking means to lock said second rod in position with the closure member lifted off said valve seat.

5. A shut-off valve as claimed in Claim 4 in which said locking means is releasable by pivoting said lever about the axis of said second rod.

6. A shut-off valve as claimed in any one of Claims 2 to 5 wherein leads to a coil of said electromagnet pass through a wall of said housing.

7. A shut-off valve as claimed in any one of Claims 2 to 6 including a conduit having an inlet thereto and an outlet therefrom with said valve seat disposed therebetween, the conduit being coupled to the base of said housing.

8. A shut-off valve substantially as described herein with reference to Figures 1 and 2 of the accompanying drawings.

9. A shut-off valve substantially as described herein with reference to Figures 3 and 4 of the accompanying drawings.