GB2293432A - Tamperproof valve - Google Patents

Abstract

A tamperproof rotary plug valve comprises a handle 11 keyed to a rotatable stem 13 and having a pair of stops 15 which are angularly spaced by 90 degrees and cooperate with a lug 14 on the valve housing 10 to define open and closed conditions of the valve. The valve may be locked in the open or closed position by removing the handle and re-orientated it on the stem 13 so that the lug 14 is received in either of two notches 16, 17. The handle is then secured on the stem by a nut 12 which is covered to prevent access to the nut by a sealing cap 20. <IMAGE>

Description

TAMPERPROOF DEVICE FOR VALVES This invention relates in general to valves for fluids, especially gases, comprising a plug with a stem connected to a handle which can be moved from a closed position to an open position by rotation through 900, such as e.g. in ball valves.

More particularly, the invention relates to tamperproof means which can be applied to the handle of a valve, either when it is used normally or when it is locked in a closed position or an open position.

Valves for fluids in which the handle and/or the plug can be secured to the valve body to prevent uncontrolled opening of the valve if it is closed and closure if it is open, for safety purposes and to prevent tampering, have already been proposed and are available. In the known embodiments the handle and/or the plug is secured to the valve body by means of a lock applied to the handle or a lock on the axis of rotation of the plug.

In every case these known systems involve the availability and use of a key, and have a not insignificant cost in relation to that of the valve alone.

The purpose of this invention on the other hand is to provide a tamperproof device for valves of the abovementioned type, which is particularly simple and economical, and convenient to apply to the handle without affecting any functional part or structure of the valve, which does not require any key and which also acts as a seal.

For this purpose the operating handle for the valve plug, in addition to having stops to determine the rotation of the handle between the open and closed positions of the plug, is provided with two rotation-preventing notches which interact alternately with a lug which is integral with the valve body to immobilise the handle in the extreme open and closed positions respectively, and a sealing cap, which can only be removed by at least partially destroying it, secured to the said handle, above the stem connecting it to the plug. The device proposed here has the following advantages, in addition to its simplicity, economy and ease of use: - it prevents undue tampering and/or dismantling of the valve.Any tampering is revealed clearly as it always results in destruction or at least deterioration of the sealing cap, - prevention of undesirable access and action from the outside, reducing the need for maintenance of the valve over time, - protection of the end of the control stem and the corresponding securing nut against external agents, impurities and rust, - provision of a pleasing closing and finishing member for the handle as it hides the unaesthetic stem/nut assembly, - provision of a support for applying and changing notices, markers, etc., with the possibility therefore of better identification of the handle and therefore of the valve itself.

Even more advantageously the sealing cap may be of plastics material of the same colour as the handle, finishing off and being flush with the upper surface of the latter and thus not creating any discontinuity between the handle and the seal.

Use of the sealing cap is easy and convenient, being applied by pressure, making use of the elasticity of engaging means integral with the sealing cap.

When the cap is in operation there is very little play between the perimeter of the cap and the seat into which it is secured, with the result that any tool used to release and remove the cap will necessarily deform it, providing evidence of the tampering which has taken place.

An embodiment of the invention will be described below in greater detail with reference to the appended drawings in which: Figure 1 shows an exploded view of the valve, handle and sealing cap, Figure 2 shows the valve and handle complete with the sealing cap in partial cross-section, and Figure 3 shows a magnified transverse cross-section of the sealing cap alone.

In these drawings, 10 indicates a valve body and 11 an operating handle having a cup or cylindrical-shaped member 11' which is secured by means of a nut 12 to the stem 13 operating the valve plug (not shown) which is located and can rotate within body 10. This body 10 has at least one lateral stop lug 14 and the cup or cylindrical portion of handle 11 has, in a known manner, two stops 15 which are angularly separated and interact alternately with stop lug 14 to define the open and closed positions of the valve following rotation of the handle through 90".

Cup or cylindrical part 11' of handle 11 also has two additional notches 16, 17 at a distance from said stops 15.

When the handle has been removed and refitted and suitably rotated, these can be caused to interact alternately with stop lug 14 on the valve body to immobilise the handle in the open and closed positions of the valve in order to prevent any possibility of rotation.

Above stem 13 and securing nut 12, portion 11' of handle 11 bounds a seat 18 with a peripheral internal groove which forms an undercut 19, and a tamperproof cap 20 which engages the said undercut is fitted in the said seat. For this purpose cap 20 has peripheral tabs 21 designed to snap onto the undercut when the cap is pressed into the said seat with any tool as shown in Figure 2. Cap 20 thus prevents access to the securing nut, uncontrolled removal of the handle and action on the plug, both when the handle is free to be rotated for normal opening and closing of the valve and when it is stably and permanently secured in the closed position or in the open position, without being able to rotate.

Finally, it should be noted that the top of tamperproof cap 20 may be provided with a peripheral edge 22 defined by an annular groove 23. This edge 22 then constitutes a weakened zone which deforms immediately if any attempt is made to remove the cap by any means, thus clearly indicating any attempted tampering and/or tampering which has taken place if the cap is replaced.

Claims (5)

1. A tamper-proof device for a valve for fluids of the type incorporating a rotating plug with a stem connected to an operating handle which can be moved from a closed position to an open position by rotation through 900 and which can be permanently secured in the closed position or the open position, the handle having a cup or cylindrical portion secured to the said stem by means of a securing nut and being provided with means to bound rotation and to define the said permanent opening and closing positions, characterised in that it comprises a sealing cap which can be engaged with the cup or cylindrical portion of the handle above the stem and the securing nut, to prevent access to these and any tampering with the valve.

2. A device according to claim 1, in which the said cup or cylindrical portion of the handle has a seat, above the said stem and securing nut, with an internal groove which defines an undercut, and in which the said sealing cap has peripheral engaging tabs designed to engage the said undercut under pressure so as to cause at least partial destruction of the cap when the latter is removed.

3. A device according to claim 2, in which the sealing cap has an edge around the periphery of its head defined by a groove and comprising a weakened zone which reveals any attempt at tampering.

4. A device according to claims 1 and 2, in which the said cap also comprises a finishing member for the handle, a safety seal and a support for various markings and/or indications.

5. A tamper-proof device for valves, substantially as herein described with reference to the accompanying drawings.