GB2313172A

GB2313172A - A valve

Info

Publication number: GB2313172A
Application number: GB9610078A
Authority: GB
Inventors: Mark A Harding; Craig Baker
Original assignee: G E Baker
Current assignee: G E Baker
Priority date: 1996-05-14
Filing date: 1996-05-14
Publication date: 1997-11-19
Also published as: GB9610078D0

Abstract

A valve for turning on and off liquid flow has a combined shock absorbent and time on delay mechanism particularly suitable in a livestock cooling device comprising a sprung piston assembly 38, an outer casing 30, a bush and valve seat 28 housing a plunger 20. This facilitates the plunger being actuated to move the piston assembly 38 towards a partially sealed chamber 26 formed between the piston assembly, the stopper 19, and the outer casing. This actuation opens the valve and simultaneously exhausts the chamber contents through a relief valve comprising the spring 32, the ball 34 and the seat 36. After actuation the plunger returns and the piston assembly is forced back to close the valve by the force of the spring 32, the time taken to close is limited by the rate at which the chamber 25 is vented through the bleed hole 37.

Description

A VALVE This invention relates to a valve with shock absorbent and on time delay features.

Valves which delay closing for a period of time after actuation are known and used in many washrooms for regulating the usage of water.

Many of these valves wear over a period of time because they depend on close fitting components which may rub against one another changing the delay time as these components wear.

Valves of this type are also limited as to their actuation by a dead stop i.e. one solid component hits another, hence if actuated by a larger force the shock is passed directly through to the mounting.

According to the present invention there is provided a valve comprising a sprung piston assembly incorporating a flexible seal, a relief valve, a bleed hole and a ring seal, whereby the flexible seal on the piston assembly co-operates with a valve seat and the ring seal allows the piston to cooperate with the valve casing, the valve also comprising a plunger, a partially sealed chamber vented by the bleed hole in the piston assembly and sealed by the ring seal, thereby when the valve is actuated the flow of liquid starts instantly from a connected supply of liquid under pressure through the valve to a nozzle or connection which is directed appropriately, hence the valve acts as a shock absorber against the actuation force, delays closing for a period of time regulated by the piston assembly, the piston return spring and the partially sealed chamber and then stops the liquids flow through the valve promptly.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a sectioned view of the valve in the closed position; Figure 2 shows an enlarged detail of the piston assembly; Figure 3 shows a sectional view of the valve when actuated; Figure 4 shows a sectional view of the valve after actuation and prior to closing.

Referring to the drawing in Figure 1 the valve comprises an outer casing 30 housing the plunger 20 which is retained in a bush and seat 28 by a sleeve 27 and sealed by seal 29. This facilitates the plunger 20 moving to actuate the piston assembly 38 detailed in Figure 2. The piston assembly partially seals a chamber 26 which houses two springs, the piston return spring 25 and overload spring 24.

These springs are located on bosses on the stopper 19 which prevents liquid leaking from the chamber 26. Referring to Figures 1 & 2 the piston assembly comprises a main body 38, a flexible seal 31 which co-operates with the bush and seat 28 to stop flow of liquid, a relief valve comprising the spring 32, the ball valve 34 and the valve seat 36. The valve seat makes provision for the bleed hole 37 and the piston body 38 makes provision for the relief vent 33 and for the seal 35 to co-operate with the piston body 38 and the valve casing 30 to make a moving seal.

Actuation of the valve causes the plunger 20 and piston assembly 38 to move from the position indicated in the drawing in Figure 1 to the position indicated in the drawing in Figure 3. Referring to the drawing in Figure 3 the plunger 20 forces the piston assembly 38 along the valve casing 30 breaking the seal between the flexible seal 31 and the bush and seat 28. This allows liquid to flow from the pressurised source at the tube 18 in direction indicated 39 to another connection pipe or the nozzle 17 where it forms a misting spray. In forcing the piston 38 along the valve casing 30 the pressure is increased in the chamber 26 which causes the relief valve comprising the ball 34, spring 32 and seat 36 to open to allow rapid exhaust of the liquid in the direction indicated 40. The actuation of the valve compresses the piston return spring 24 and will then act on the overload spring. The fluid in the chamber co-operates with the piston to act as a shock absorber, the rate of fluid exhaust having a limitation even with the relief valve open.

When the force is released the water pressure is able to force out the plunger 20 to cause it to retum to the original position. The valve is now in the position indicated in the drawing in Figure 4.

Referring to the diagram in Figure 4 the plunger 20 is now in the original position as per the diagram in Figure 1. The pressure drops in the chamber 26 by the action of the piston retum spring 25 which closes the relief valve. The chamber is therefore sealed except for the bleed hole 37 incorporated in the relief valve seat 36. The piston assembly is retumed to the closed position indicated in the diagram in Figure 1 by the spring 25 as the chamber 26 is vented through the bleed hole 37 by liquid moving in direction indicated 41.

The time that the piston assembly takes to retum to the closed position can be varied by the size of the chamber 26, the diameter of the bleed hole 37, or the force applied by the spring 25.

Claims

1. A valve comprising a sprung piston assembly incorporating a flexible seal, a relief valve, a bleed hole and a ring seal, whereby the flexible seal on the piston assembly co-operates with a valve seat and the ring seal allows the piston to co-operate with the valve casing, the valve also comprising a plunger, a partially sealed chamber vented by the bleed hole in the piston assembly and sealed by the ring seal, thereby when the valve is actuated the flow of liquid starts instantly from a connected supply of liquid under pressure through the valve to a nozzle or connection which is directed appropriateiy, hence the valve acts as a shock absorber against the actuation force, delays closing for a period of time regulated by the piston assembly, the piston retum spring and the partially sealed chamber and then stops the liquids flow through the valve promptly.

2. A valve as claimed in Claim 1 wherein the period of on delay time can be changed by modifying the size of the bleed hole.

3. A valve as claimed in Claim 1 and Claim 2 wherein the period of on delay time can be changed by modifying either the spring rate of the piston return spring or length of this spring

4. A valve as claimed in the preceding claims wherein the period of on delay time can be changed by modifying the size of the partially vented chamber.

5. A valve as claimed in the preceding claims wherein wear of components is reduced by using flexible seals to bear between the moving components.

6. A valve as claimed in the preceding claims wherein a means of connection is made to enable actuation at one end and a fixed point at the other.

7. A valve substantially as described herein with reference to Figures 14 of the accompanying drawings.