GB2270141A

GB2270141A - Lock mechanism for a ball valve

Info

Publication number: GB2270141A
Application number: GB9317467A
Authority: GB
Inventors: Roger Harold Creasey; John Baker
Original assignee: CONFLOW Ltd
Current assignee: CONFLOW Ltd
Priority date: 1992-08-27
Filing date: 1993-08-23
Publication date: 1994-03-02
Also published as: GB9218228D0; GB9317467D0

Abstract

A safety fitting (16) for a lever-actuable ball valve (1) comprises a spring-loaded latch arrangement (21 - 24), so that the valve lever (11) cannot be turned from the "off" position to the "on" position until a spring-loaded latch (21) is manually depressed clear of the lever (11). The fitting (16) includes a collar (17) which encircles the housing (2) of the ball valve and is secured thereto by a grub screw. <IMAGE>

Description

BALL STOP VALVE ETC This invention relates to a safety fitting for a ball stop valve, and to a ball stop valve provided with such a fitting.

Conventionally, ball stop valves have a 900 lever movement from fully "off" to fully "on" and, unlike screw down globe type valves (where the valve is gradually opened or closed by turning the handle many times to obtain either full bore or closure), the ball type stop valve is fully "on" in one 900 movement.

This often can cause a safety problem especially if the valve is fitted on the end of a flexible hose where firstly neither valve nor hose is restrained (by clamps etc), and where secondly, as is frequently the case, the hose is pressurised, e.g. at 150 p.s.i. or more, so that pressure fluid, e.g. water or a water/oil emulsion, is always available upon demand by a user. With the valve in the "off" position a dangerous situation can occur if the valve lever is inadvertently turned to the "on" position, e.g. by snagging or being knocked by a moving object or machine.

This inadvertent action can often occur in a mining environment where the flexible hose can be moved, e.g. by movement of a coal winning machine or a self-advancing roof support, thereby trailing the valve along the mine floor.

The lever can then snag on the uneven surface, turn fully "on", with the valve, and the end portion of the flexible hose whipping out of control into the air, due to the sudden release of fluid from the valve. In practice this is not an infrequent occurrence, because traditionally the lever is in the "off" position at 900 to the valve body increasing the propensity for snagging.

According to a first aspect of the present invention, there is provided a safety fitting for a lever-actuable ball stop valve, the fitting comprising a spring-loaded latch arrangement, so that the valve lever cannot be turned from the "off" position to the "on" position until a spring loaded latch is manually depressed clear of the lever.

According to a second aspect of the invention, there is provided a ball stop valve incorporating a fitting as defined above.

Thus, with the fitting and valve in accordance with the invention, no single movement, as with prior art levers, is required to open the valve, but on the contrary two movements are required, which makes it virtually impossible for the lever to be moved inadvertently to the open position, should a hose be dragged along the ground by other machinery.

Furthermore, the invention provides the additional advantage of being fittable to both new and existing valves without disassembling the original product.

Preferably, the latch arrangement comprises a spring loaded plunger biassed by the spring to a projecting position so as to block lever movement, with the plunger being depressable by a thumb of the user against the spring to a retracted position. It is also preferred for the plunger to be displaceable along an axis parallel to the axis of rotation of the ball, with the lever extending radially or generally so, from the ball rotation axis. The lever is preferably cranked, and a terminal end of the plunger is preferably rounded so that it "rides" under the lever without jamming or trapping the user's finger.

The safety fitting preferably further comprises a collar adapted to embrace a portion of the external periphery of the body of the valve, to be rigidly secured in position on the valve body by a locking screw engaging a flat or the valve body.

The two aspects of the invention will now be described in greater detail, by way of example, with reference to the accompanying drawings in which: Figure 1 is a plan view of a fitting in accordance with the first aspect applied to a ball stop valve in accordance with the second aspect; Figure 2 is an end elevation of Figure 1; Figure 3 is a plan view of Figure 1; and Figure 4 is an axial sectional view through Figure 1.

The ball stop valve 1 comprises a valve body 2 with a through bore for fluid flow defined by a bore part 3 in the valve body 2 and a bore part 4 in an end cap 5 provided with a hexagon head 6 and screwed into the valve body 1. Both the end cap 5 and valve body 2 are counterbored and tapped at 7 to receive a screw-in end fitting (not shown) of hoses (not shown). Between bore parts 3 and 4 a ball 8 is located with ball seating rings 9 and a bore 10 which is alignable with the bore parts 3 and 4 in the valve "on" position to permit fluid flow and rotated through 900 to the valve "off" position to prevent fluid flow by the user operating a cranked handle or lever 11 fitted onto a drive spindle 12 with a drive nose 13 engaged in a recess 14 of the ball 8 to rotate the ball about an axis 15.A safety fitting 16 is secured to the valve body by a collar 17 embracing a portion of the external periphery of the valve body 1 and secured in position by a locking screw 18 engaging a flat 19 on the valve body 1. The safety fitting 19 comprises a latch arrangement 20 in the form of a plunger 21 biassed into a projecting position by a spring 22, and is depressable by a thumb of the user along an axis 23 parallel to the axis 15, with terminal end 24 of the plunger rounded.

The valve 1 is shown with the lever 11 in the "off 11 position in Figures 1 and 2 and the "on" position in Figures 3 and 4. In the "off" position the lever 11 cannot be turned into the "on" position because it is physically prevented to do so by the projection of the plunger 21 impeding lever rotation, as can best be appreciated from Figure 2, the spring loading of the plunger 21 allowing the lever 11 to pass over when the plunger 21 is depressed. This two-function, combined operation can usually be carried out with one hand.

The rounded end 24 makes depressing comfortable to the thumb and also enables it to "ride" past the underside of the lever.

The safety fitting 16 may be a separate unit to the ball valve itself. In this way it can be retrofitted to existing ball stop valves, as it is readily located and secured on the valve with its locking screw 18 and is prevented from rotating on the cylindrical body 2 of the ball valve 1 by being sited against the flat 19.

An identical safety fitting 16 is suitable for use with a range of ball valve sizes, e.g. 1/2"; 3/4"; 1", and 1.1/4".

Claims

.1. A safety fitting for a lever-actuable ball stop valve, the fitting comprising a spring-loaded latch arrangement, so that the valve lever cannot be turned from the "off" position to the "on" position until a spring loaded latch is manually depressed clear of the lever.
2. A safety fitting as claimed in Claim 1, wherein the latch arrangement comprises a spring loaded plunger biassed by the spring to a projecting position so as to block lever movement, with the plunger being depressable by a thumb of the user against the spring to a retracted position.
3. A safety fitting as claimed in Claim 1 or Claim 2, wherein the plunger is displaceable along an axis parallel to the axis of rotation of the ball, with the lever extending radially or generally so, from the ball rotation axis.
4. A safety fitting as claimed in any preceding Claim, wherein the lever is cranked.
5. A safety fitting as claimed in any preceding Claim, wherein a terminal end of the plunger is rounded.
6. A safety fitting as claimed in any preceding Claim, comprising a collar adapted to embrace a portion of the external periphery of the body of the valve.
7. A safety fitting as claimed in Claim 6, wherein the collar is rigidly securable in position on the valve body by a locking screw engaging a flat or the valve body.
8. A safety fitting substantially as hereinbefore described with reference to the accompany drawings.
9. A ball stop valve incorporating a fitting as defined in any preceding Claim.
10. A ball stop valve substantially as hereinbefore described with reference to the accompanying drawings.