GB2142710A - Valve - Google Patents

Abstract

The present invention relates to a butterfly valve comprising a valve housing 2 with a pivotally mounted valve disc 7 rotatable between an open position and a closed position in which it extends across a valve passage through the valve housing. According to this invention the valve housing 2 is provided with a proximity sensor 13 disposed substantially directly opposite a part of the valve disc edge 10 substantially spaced apart from the rotational axis of said valve disc 7 in its closed position. The proximity sensor 13 is connected 16 to a remote output display means 17 formed and arranged so as to display respective indications of fully closed and not fully closed positions of the valve disc 7. <IMAGE>

Description

SPECIFICATION Valve This invention relates to valves and in particular to a valve with indicator means for indicating the closed position thereof.

In many prqcessing installations having more or less complex pipework systems for handling various fluids, especially in food grade.installations for handling liquids such as milk or beer, it is vitally important that valves be properly closed to avoid any possibility of contamination-of the product. With certain types of valves such as conventional butterfly valves the only ind.ication that the valve is in its fully closed position is through the position of the valve stem and control handle or lever mounted thereon. Even a small deviation ofonly a few degrees can however provide improper sealing with leakage through the valve so that a relatively small deformation of the valve stem due to for example the application of an excessive turning force thereto can give rise to a seriously misleading indication of valve member position.In many such known systems it is also difficult or inconvenient to provide a remote indication corresponding to the actual valve member position.

It is an object of the present invention to avoid or minimize one or more of the above disadvantages.

The present invention provides a butterfly valve comprising a valve housing with a pivotally mounted valve disc rotatable between an open position and a closed position in which it extends across a valve passage through said valve housing, said valve housing being provided with a proximity sensor means disposed substantially directly opposite a part of the valve disc edge substantially spaced apart from the rotational axis of said valve disc in the closed position of the valve disc, said proximity sensor means having a connection means for connection, in use, to a remote output display means formed and arranged so as to display respective indications of fully closed and not fully closed positions of the valve disc.

With a valve of the present invention it is possible to obtain a reliable positive indication of proper valve closing even when there are deficiencies in the valve closing system whereby the security of an installation including a valve of the present'invention against accidental cross-contamination is significantly improved.

Further preferred features and advantages of the invention will appear from the following detailed description given by way of example of a preferred embodiment illustrated with reference to the accompanying drawings in which: Figure 1 which is a partially sectioned end elevation of a valve of the invention; and Figure 2 is a detail longitudinal plane section on the line A-A in Fig. 1 through the sensor of the valve.

Fig. 1 shows a butterfly valve 1 comprising a valve housing 2 pivotally mounting 3 a valve stem 4 having a control wheel 5 at one end 6 and a valve disc 7 at its other end 8.

The valve housing 2 is provided with an annular valve seal member 9 of a resiliently deformable polymeric material such as natural or synthetic rubber or silicon rubber which sealingly engages the outer edge 10 of the valve disc 7 in the fully closed position of the latter. The fully closed position of the valve disc 7 is shown in solid line in Fig. 2 whilst the fully open position is indicated in dashed outline.

At one side, substantially- spaced from the vertical rotational axis of the valve disc 7 and valve stem 4, the valve housing 2 is provided with a radially extending bore 11 in which is secured the distal end 1 2 of an elongate sensor device 1 3. The sensor device 1 3 has a proximity sensor means 14 in said distal end 1 2 which abuts the radially outer side 1 5 of the seal member 9 directly opposite the edge 10 of the valve disc 7 in the fully closed position of the latter and is formed and arranged so as to produce an output in response to detection of the valve disc edge in close proximity thereto.The output is transmitted via suitable, preferably screened, connector leads 1 6 to a remote indicator means such as a visual display unit e.g. a liquid crystal display or indicator light 1 7.

Various forms of proximity sensor means may be used in accordance with the present invention depending on the precise material from which the valve disc is made. This is usually a metal, for example, brass or more conveniently a ferro-magnetic material such as steel, especially stainless steel. Amongst the types of proximity sensor means that may be used are capacitative, inductive and eddycurrent proximity sensors.Conveniently the sensor device is constructed in the form of a tubular outer housing having a detector element, for example, an induction coil, mounted in the distal end, an electrical circuit means connected to said element and formed and arranged for monitoring variations in current flow through the element in response to relative movement of Xhe valve disc with respect to the element and for providing a predetermined output signal corresponding to disposition of the valve disc directly opposite the sensor. Suitable connector leads are provided for connection of the circuit to a remote display unit and conveniently also to a remote electrical power supply.

The sensor device is desirably of a relatively robust construction preferably using solid state circuitry sealed in an inert non-conductive resin inside a metal or plastics material housing.

Claims (8)

1. A butterfly valve comprising a valve housing with a pivotally mounted valve disc rotatable between an open position and a closed position in which it extends across a valve passage through said valve housing, said valve housing being provided with a proximity sensor means disposed substantially directly opposite a partpf the valve disc edge substantially spaced apart from the rotational axis of said valve disc in the closed position of the valve disc, said proximity sensor means having a connection means for connection, in use, to a remote output display means formed and arranged so as to display respective indications of fully closed and not fully closed positions of the valve disc.

2. A valve as claimed in claim 1 wherein said sensor means is mounted in a generally radially extending bore in said housing.

3. A valve as claimed in claim 2 wherein the longitudinal axis of said bore extends at an angle of at least 30 from the rotational axis of the valve disc.

4. A valve as claimed in claim 3 wherein said angle is at least 45 .

5. A valve as claimed in any one of claims 1 to 4 wherein said sensor means is selected from a capacitative, an inductive and an eddy current type proximity sensor means.

6. A valve as claimed in any one of claims 1 to 5 wherein said housing includes an annular seal member mounted in the valve passage for sealing engagement with the valve disc edge in the closed position of the valve,disc, and wherein said sensor means is disposed in close proximity behind the radially outer side of said seal member.

7. A valve as claimed in any one of claims 1 to 6 wherein said sensor means is connected to a visual display unit.

8. A butterfly valve substantially as described hereinbefore with particular reference to Figs. 1 and 2 of the accompanying drawings.