GB2137736A

GB2137736A - Fluid valve

Info

Publication number: GB2137736A
Application number: GB08403984A
Authority: GB
Inventors: William Rupert Nicholas; Ian Gordon Wells; Lance Vane Lansell
Original assignee: LCL Pty Ltd
Current assignee: LCL Pty Ltd
Priority date: 1983-02-18
Filing date: 1984-02-15
Publication date: 1984-10-10
Also published as: SG74987G; GB8403984D0; GB2137736B; MY8700713A; HK15288A

Abstract

A fluid valve (10) with enhanced durability and lower rate of wear and greater capacity to seal worn/rough seat surfaces comprising (1) a valve stem; (2) a valve disc (12) including: (a) an upper surface co-operating with the valve stem; and (b) an annular recess (18) in a lower surface thereof; and (3) retaining means (20) disposed in the annular recess (18) and defining a channel (23) therebetween; and (4) a ring seal (24) disposed in the channel (23) and axially projecting from the lower surface, the retaining means (20) including a passageway (25) cooperating with the annular recess (18) to permit ingress of fluid into the channel (23) to exert outward pressure on the ring seal (24). <IMAGE>

Description

SPECIFICATION Fluid valve This invention relates to an improved fluid valve for taps and similar control devices. Whilst the following description is particular to use of the valve in taps it is not so limited. Typically the valve may be used in other devices e.g. globe valve.

Fluid valves usually comprise a valve disc attached to a valve stem. The disc is provided with a sealing washer adapted to cooperate with a valve seat in the tap body, the valve seat surrounding an opening through which fluid can flow. The valve stem is received within an axial bore of the tap spindle. The sealing washer provides the actual contact with the valve seat and thus stop the flow of fluid. To open the tap the disc is raised by rotating the spindle thus taking the force off the disc. The valve lifts off its seat by pressure of the fluid flowing through the valve.

Counter-rotation of the spindle brings the valve disc sealing washer into contact with the valve seat and thus closes the tap.

Known fluid valves are provided with a sealing washer fixed to the valve disc by a screw or rivet.

Another known fluid valve is manufactured entirely from plastic (e.g. nylon), thus not requiring a separate sealing washer. These valves do not seal well if the valve seat is worn or rough.

Known fluid valves discussed above usually have a high wear rate necessitating frequent replacement. Another source of wear arises from friction between spindle and valve stem, causing rotational "skidding" of the sealing washer on the valve seat.

It is the object of this invention to provide a fluid valve with enhanced durability and lower rate of wear and greater capacity to seal worn/rough seat surfaces.

This object is achieved by a valve comprising: (1) a valve stem: (2) a valve disc including: (a) an upper surface co-operating with the valve stem; and (b) an annular recess in a lower surface thereof; and (3) retaining means disposed in the annular recess and defining a channel therebetween; and (4) a ring seal disposed in the channel and axially projecting from the lower surface, the retaining means including a passageway cooperating with the annular recess to permit ingress of fluid into the channel to exert outward pressure on the ring seal.

It has been found that some configurations of the invention produce noise in certain circumstances. Substantial reduction of such noise may be achieved by providing the lower surface of the valve disc with a chamfered peripheral edge.

In another preferred embodiment the channel has a depth less than the cross-sectional dimension of the ring seal so that the seal projects from the lower surface of the valve disc.

In a further preferred embodiment the channel has an opening which is less than the crosssectional dimension of the ring seal. This arrangement ensures the ring seal is retained in the annular recess securely.

To facilitate the last mentioned preferred embodiment it is desirable to undercut the channel to enable sufficient space for the bulk of the ring seal to be accommodated. Similarly where a retaining plate is used to form one side of the channel it is convenient to bevel its periphery to form an undercut surface. Typically the channel in these instances adopts a trapezium crosssectional shape. However, it is clear the exact cross-sectional shape of the channel is not so limited. For instance it may have curved walls.

In another preferred embodiment the passageway in the retaining means, cooperating with the annular recess, permits ingress of fluid into a base section of the channel.

In another preferred embodiment a clearance between the retaining plate and disc may also be provided. In this arrangement the passageway communicates with the channel via the clearance to give a throttling effect and prevent rapid build up of pressure behind the ring seal, thus reducing the possibility of forcing the ring out of the recess.

In another preferred embodiment a spacer, typically of plastics material, is provided on the valve stem and communicates with the upper surface of the valve disc. This reduces friction between the valve and tap spindle to further reduce wear of the valve.

In another preferred embodiment the lower surface of the valve disc additionally includes a second sealing surface. More particuiarly the second sealing surface may be located in the area defined between the peripheral edge of the lower surface and the recess. Alternatively the second sealing surface may be provided by means associated with the retaining means.

The invention also provides a tap provided with a fluid valve as defined above.

The invention will now be described with reference to the accompanying drawings in which: Figure 1 is a side elevation of a valve of the invention; Figure 2 is a side cross-sectional elevation of a valve of the invention in a conventional tap; Figure 3 is an exploded partial cross-section of a one portion of a valve of the invention.

Figure 4 is an exploded partial cross-section of a one portion of a valve of the invention.

The drawings show a valve 10 having a valve stem 11 and a valve disc 12. Valve stem 11 is received in the bore 1 3 of axially movable tap spindle 14. The valve stem 11 is provided with a plastic spacer 1 5 which engages the end 1 6 of spindle 14 and reduces friction therebetween.

Reducing friction at this point reduces rotation of the valve on the valve seat 17 of the tap thus reducing wear on the sealing means.

Valve disc 12 is provided with an annular recess 18 which is undercut at its periphery, as indicated by numeral 1 9. A circular retaining plate 20 having a bevelled periphery 21 is arranged to fit in annular recess 18 by means of a deformed extension 22 (see Fig. 2) of the valve stem, or by means of a screw or nut. The recess 18 and retaining plate 20 form a trapezium shaped channel 23 to accommodate an O-ring seal 24. A passageway 25 is provided through the annular retaining plate 20.

The valve operates in the following manner. To close the tap, spindle 14 is rotated until the ring seal 24 contacts the valve seat 17. This contact provides the primary seal. However on contact an increase in water pressure at the retaining plate 20 forces the fluid through passageway 25 along clearance 1 8 to the rear of the 0 ring seal as illustrated by the arrows. This forces the 0 ring seal 24 harder onto the valve seat 1 7 to provide additional sealing. Clearance 1 8 produces a throttling effect to the water pressure to prevent rapid build up of pressure to force the O-ring seal out of its groove. After long use when the tap is fully closed an additional sealing effect can be provided by metal to metal contact between valve disc 12 and valve seat 17.

In accordance with a preferred embodiment at the present invention, valve disc 12 is provided at its lower periphery with a chamber 26. This chamber reduces the venturi effect present with a square edge, and thereby reduce noise when the top is partly open.

Advantages of a valve constructed in accordance with the invention include the feature that should the ring seal fail or deteriorate, a metal to metal seal is still available to substantially close the tap. Similarly, with an O-ring seal the small contact area effectively seals on scored or worn tap seats. The spacer on the valve stem reduces friction between spindle and valve, and also gives a "soft" feel to the tap action and prevents jamming if the tap is over-tightened. The ring seal is also protected in the event of over-tightening, and the softer rubber of the ring and its shape can more readily cope with particles between the valve and seat without the seat or valve being damaged.

Claims

1. A valve comprising: (1) a valve stem; (b) a valve disc including: (a) an upper surface co-operating with the valve stem; and (b) an annular recess in a lower surface thereof; and (3) retaining means disposed in the annular recess and defining a channel therebetween; and (4) a ring seal disposed in the channel and axially projecting from the lower surface, the retaining means including a passageway cooperating with the annular recess to permit ingress of fluid into the channel to exert outward pressure on the ring seal.

2. A valve according to claim 1 wherein the lower surface of the valve disc has a chamfered peripheral edge.

3. A valve according to claim 1 or 2 wherein the retaining means is a plate.

4. A valve according to any one of claims 1 to 3 wherein the channel has a depth less than the cross-sectional dimension of the ring seal.

5. A valve according to any one of claims 1 to 4 wherein the channel has an outer opening which is less than the cross-sectional dimension of the ring seal.

6. A valve according to any one of claims 1 to 5 wherein the channel is undercut.

7. A valve according to any one of claims 1 to 6 wherein the retaining means has a bevelled periphery forming one undercut side of the channel.

8. A valve according to any one of claims 1 to 7 wherein the passageway of the retaining means cooperates with the annular recess to permit ingress of fluid into a base section of the channel.

9. A valve according to claim 8 wherein the retaining means is axially displaced from the valve disc.

1 0. A valve according to any one of claims 1 to 9 additionally including a spacer located on the valve stem and communicating with the upper surface of the valve disc.

11. A valve according to any one of claims 1 to 1 0 wherein the lower surface of the valve disc additional includes a second sealing surface.

12. A valve substantially as hereinbefore described with reference to the accompanying drawing.

13. A device including a valve according to any one of claims 1 to 12.

14. A device according to claim 1 3 which is a tap.