GB2242726A

GB2242726A - Stop device for quarter turn valves

Info

Publication number: GB2242726A
Application number: GB9007960A
Authority: GB
Inventors: Ian Leslie Price
Original assignee: Hattersley Newman Hender Ltd
Current assignee: Olympus Ormskirk Ltd
Priority date: 1990-04-07
Filing date: 1990-04-07
Publication date: 1991-10-09
Anticipated expiration: 2010-04-07
Also published as: GB9007960D0; GB2242726B

Abstract

A gear operated valve has a variable stop comprising an adjustable travel stop 3 and an eccentric stop 6. With the valve opened to a desired regulating position, the adjustable travel stop 3 may be disengaged from and rotated relative to a drive adaptor 2 attached to a gear quadrant forming part of a reduction gear of the valve and reengaged on the adaptor 2 in the desired position. The eccentric stop is then adjusted until it abuts the adjustable stop. Thereafter the valve may be repeatedly opened to the desired regulating position by opening it until the two stops once again abut. <IMAGE>

Description

MEMORY STOP DEVICE FOR QUARTER TURN VALVES The present invention relates to a memory stop device for a quarter turn valve.

Quarter turn valves are normally operated manually by either lever (wrench) or reduction gear operator. When used as a regulating device, the quarter turn valve will be set in a partially open position which is critical to achieve desired flow conditions and hence the setting mechanism should be infinitely variable. However, there is a requirement for the valve to be closed for isolation purposes and then returned precisely to the pre-determined partially open position. Examples of quarter turn valves are ball, butterfly and plug-type valves.

According to the present invention, there is provided a variable memory stop device for a quarter turn valve comprising a first adjustable stop which can be adjusted to an adjusted regulating position of the valve closure member, and fixed in that position relative to the valve closure member and a second adjustable stop which can be adjusted to a position to act as a stop for the first stop when in its adjusted position whereby the regulating position of the valve closure member can be repeatedly selected.

In a preferred embodiment of the invention, the first adjustable stop is a travel stop and is connected to the valve through a drive adaptor. The drive adaptor comprises a splined boss which cooperates with a complementary splined bore on the first adjustable stop. The second adjustable stop is an eccentric stop which is rotatably fixed to the cover of a gear operator to enable the valve to indicate the degree of opening of the valve in cooperation with a pointer on the drive adaptor. In operation, the valve is adjusted to its desired regulated position and the adjustable travel stop is, disengaged from the drive adaptor, rotated and reengaged on the drive adaptor as close as possible to the eccentric stop.This eccentric stop is then adjusted to close any gap between the contact faces of the adjustable travel stop and the eccentric stop for intimate contact and tightened in that position.

This, then, accomodates the infinitely variable positioning of the valve. When the valve is closed, it may simply be reopened to the regulating position by opening the valve until the two stops again abutt.

In order that the invention may be more clearly understood, one embodiment thereof will now be described, by way of example, with reference to the acompanying drawings, in which: Figure 1 shows a plan view of a quarter turn valve gear operator including a memory stop device according to the invention.

Figure 2 shows a drive adaptor forming part of the stop device shown in Figure 1, Figure 3 shows an adjustable travel stop forming part of the stop device shown in Figure 1, Figure 4 shows a washer forming part of the stop device shown in Figure 1, Figure 5 shows a short screw forming part of the stop device shown in Figure 1, Figure 6 shows a long screw forming part of the stop device shown in Figure 1, Figure 7 shows an eccentric stop forming part of the stop device shown in Figure 1, and Figure 8 shows an indicator forming part of the stop device shown in Figure 1.

Referring to Figure 1, a quarter turn gear operator is shown housing a reduction gear. The reduction gear comprises an input shaft 11 to which an operating handle 12 is connected. A drive adaptor 2 (shown in Figure 2) is attached to a gear quadrant forming part of the reduction gear and embodies a pointer 21 for position indication and a serrated (or splined) boss 22. An adjustable travel stop 3 (see Figure 3) with a serrated bore 31 is fitted to the drive adaptor 2 and is retained by a washer 4 (see Figure 4) and screw 5 (see Figure 5) which fits into a tapped hole 23 in the drive adaptor 2.

A cover retaining screw on the gear operator is removed and discarded and replaced by an eccentric stop 6 (see Figure 6) and screw 7 (see Figure 7).

The drive adaptor 2, adjustable travel stop 3, washer 4 and eccentric stop 6 may be manufactured in metal or composite material. An additional position indication scale 8 (see Figure 8) with numbered graduation is fixed to the top of the gear operator.

To prevent unauthorised movement of the valve from its regulating position, a locking device on the input shaft of the gearbox is provided.

When assembled at the factory, the adjustable travel stop 3 is located such that operation of the valve between full open and full closed positions is possible.

After the valve has been regulated to the required position, the screw 5 is released sufficiently to allow disengagement of the adjustable travel stop 3 from the drive adaptor 2.

The adjustable travel stop 3 is then rotated until it can be re-engaged on the drive adaptor 2 spline as close as possible to the eccentric stop 6.

Scew 5 is then tightened to lock the adjustable travel stop in position. Screw 7 is released to allow free rotation of the eccentric stop 6 until intimate contact is made with the straight face 32 of the adjustable travel stop 3. Screw 7 is then re-tightened. If the valve is then closed, it may be reopened to the regulating position simply by opening the valve until the two stops again abutt.

If it is required to retain the regulated position against intentional or unintentional movement then a lock mechanism is engaged to the locking device.

The above described arrangement provides an infinitely variable memory stop device for fitting to gear operators. The addition of the memory stop device is accomplished without major changes to the construction of the gear operator. Specifically no machining is required to the case of the gear operator. The device can be retrofitted to existing products in use. Positive drive is provided between gear quadrant and adjustable travel stop. No devices such as slotted stop plates relying only on friction retention are included. There are no loose parts to remove and re-position during setting. The device may be made from corrosion resistant materials.

It will be appreciated that the above embodiment has been described by way of example only and that many variations are possible without departing from the scope of the invention.

Claims

1. A variable memory stop device for a quarter turn valve comprising a first adjustable stop which can be adjusted to an adjusted regulating position of the valve closure member, and fixed in that position relative to the valve closure member and a second adjustable stop which can be adjusted to a position to a-ct as a stop for the first stop when in its adjusted position whereby the regulating position of the valve closure member can be repeatedly selected.

2. A variable memory stop as claimed in claim 1, in which the first adjustable stop is a travel stop and is connected to the valve through a drive adaptor.

3. A variable memory stop as claimed in claim 2, in which the drive adaptor comprises a splined boss which cooperates with a complementary splined bore on the first adjustable stop.

4. A variable memory stop as claimed in claim 2 or 3, in which the second adjustable stop is rotatably fixed to the cover of a gear operator to enable the valve to indicate the degree of opening of the valve in cooperation with a pointer on the drive adaptor.

5. A variable memory stop as claimed in claim 2, 3 or 4, in which, in operation, the valve is adjusted to its desired regulated pointer and the adjustable stop is disengaged from the drive adaptor, rotated and reengaged on the drive adaptor as close as possible to the eccentric stop, the eccentric stop then being adjusted to close any gap between the contact faces of the adjustable travel stop and the eccentric stop for intimate contact and tightened in that position.

6. A variable memory stop as claimed in any of claims 2 to 5, in which the drive adaptor is attached to a gear quadrant forming part of a reduction gear.

7. A variable memory stop as claimed in claim 6, in which a locking device is provided on the gear input shaft to prevent unauthorised movement of the valve from its regulated position.

8. A variable memory stop for a quarter turn valve substantially as hereinbefore described with reference to the accompanying drawings.