GB2190465A

GB2190465A - A valve assembly

Info

Publication number: GB2190465A
Application number: GB08611886A
Authority: GB
Inventors: Joseph Anthony Griffiths
Original assignee: C R M DESIGN SERVICES Ltd
Current assignee: C R M DESIGN SERVICES Ltd
Priority date: 1986-05-15
Filing date: 1986-05-15
Publication date: 1987-11-18
Also published as: GB8611886D0

Abstract

A one way valve assembly includes a flexible one-piece valve member (6) held in position against a valve seat (4) adjacent an outlet (3) in a valve body (1) by stretching a stem (7) extending therefrom and anchoring it by means (8) at an opposite end of the valve body (1 ), the stem (7) extending through a chamber (5) of greater diameter than the stem (7), said chamber (5) having inlet passageways (2, 2a) communicating therewith, such that the valve will only open at a predetermined pressure, e.g. 7 p.s.i. The valve member comprises natural or synthetic rubber material. <IMAGE>

Description

SPECIFICATION Valve assembly This I nvention relatesto aonewayval.veMassernblSf in whichlthe vàlve member is biassed so as to he normally dosed but which opens whenapressure is applied thereto.

One wayvalves of thins type are known but they tend to be complicated in construction because the valve member is held in its normally closed position by means ofsome mechanical means such as a spring.

An example of such a valve is a spring loaded ball valve.

These valves work perfectly satisfactorily in normal climatic conditions but in a hostile climatic environment, the moving parts ofthe valve can become damaged wherebythevalve either works only inter mittentlyorit stops working altogether.

It is an object ofthe invention therefore to provide a simple and reliablevalveassemblywhich is cheap to manufacture and has the minimum of separate parts.

According to the invention, there is provided a one-way valve comprising a valve body provided with an inlet and an outlet, a valve seat adjacent the outlet, a chamber connecting the valve seat to the inlet and a one-piece flexible valve member having a head and a stem portion extending therefrom, said stem being anchored to the valve body by means such that, in use, the head will only lift from the seat ata predetermined pressure.

Conveniently the valve head has a sealing surface thereon shaped to communicate with the valve seat, the stem portion extending through the chamber along its longitudinal axis.

In a preferred embodiment, the valve stem is anchored at the end of the chamber remote from the valve seat, the end ofthe stem being formed with a protruberance which is a greater diameterthan the stem and is anchored in a hole in the end wall ofthe chamber. The protruberance can be any convenient shape but preferably it informed as an inverted cone whereby the undersurface ofsaid cone seats against the exterior end face ofthe valve body surrounding the hole.

Preferably a tail extends from the protruberance coaxiallywith the stem, the purpose ofthis tail being to facilitate insertion ofthevalve member in the valve body.

Conveniently the valve head isfrusto-conicalto provide an inclined surfaceto co-operate with a correspondlyshaped surface on the valve seat. The shape and configuration ofthe valve seat and the sealing surface on the valve member is not crucial to the invention and it can take any convenient shape or form. For instance the valve seat can bea radially extending plane surface provided at one end of the chamber. With such an arrangementthevalve head can includna p ane. radial l.\c extend ng; surfaceshaped.

to co.-operate and! seal with the radiatly- exten ding vaEveseatsurEaceor atternativ-ety-thevalve head can include a downwardly depending annular lip shaped to co-operate and seal with said radially extending valve seat surface.

Preferrablythe chamber is coaxial with the valve stem and of a greater diameter than said stem th throughout the part of its length between the valve seat and where the inlet opens into said chamber.

Conveniently the inlet is a passageway which extends from the exterior ofthe valve body to the chamber, this passageway entering the chamber at a location spaced from the valve seat. One or more inlet passageways may be provided.

It is an important feature ofthe preferred embodiment ofthe invention that the stem is stretched during insertion into the valve body, and anchored in its stretched condition thereby pre-tensioning the valve head so that, in use, it is firmly held in contact with the valve seat and only iifts therefrom at said predetermined pressure.

Preferrablythevalve member is made from a natural orsynthetic rubber material and it will be appreciated that by varying the ingredients of the rubber mix, the stretch value of the valve stem can be varied so that the valve can be madeto open at any required pressure. The preferred embodiment valve member is designed to operate at a pressure of 7 p.s.i.

A preferred embodiment of the invention will now be described by way of example only with referenceto the accompanying drawing which shows a valve body 1 formed at one end with threads 10. Conveniently the valve body 1 is in the form of a hexagonal nut for ease of attachmentthereofto the piece of equipmentto which it is to befitted. An O-ring 11 is fitted around the threaded portion 10 to ensurethata proper seal is made when the valve body is fitted to said other piece of equipment.

The valve body 1 is provided with an inlet2 which communicates with an outlet3 by means of a chamber 5. In the illustrated embodiment, an additional inlet 2a is provided and it is to be understood that the valve can include as many inlet passageways as are required, these passageways radiating outwardly from the central chamberS.

The outlet 3 is formed with a valve seat 4which is in theform of an inclined annularsurface. The chamber 5 is coaxial with the outlet 3 and is of a reduced diameter and the bottom thereof informed with a central hole 9.

A one-piece valve member moulded from a flexible natural or synthetic material is fitted in the valve body 1 in the manner to be described shortly. This valve member comprises a valve head 6 having a valve stem 7 extending therefrom at the end ofwhich anchoring means 8 are provided. A tail 12 extends from the anchoring means 8 coaxial with the stem 7 and is of a reduced diameterto the stem 7. The purpose ofthis tail will be described shortly.

The diameter of the valve stem 7 is less than the diameter ofthe chamber Sto allow the passage of fluid from the inlets 2, 2a through to the outlet3 pastthe valve head 6.. It is an importantfeature of the invention that the valve stem be of a lesser dia meterthanthe chamber Sto ensure that this space is always present.

The whole ofthe valve stern 7 need not be of a reduced diameter but it is importantthatthe part which extends between the inlets 2, 2a and the valve seat 4 is of the reduced diameter to ensure that the required fluid passage is present.

The valve member is moulded in one-piece from a natural or synthetic material, preferrably rubber or silicone, and it is inserted in the valve body 1 by feeding the tail 12 through the hole 9 and then pulling the tail so that the stem 7 stretches until the anchoring means 8 which, in the illustrated embodiment, is an inverted cone, passes through the hole 9 and then seats against the exterior surface ofthevalve body 1 surrounded the holeto retain the valve member in the body in a pre-tensioned condition. Once inserted therein, the tail 12 can be cut off if desired.

It will be seen from the foregoing description that because the stem 7 has been stretched during assembly, the valve head 6 is kept in sealing engage mentwith the valve seat 4 untii such time as fluid entering the inlets 2,2a reaches a pressure atwhich it will lift the valve head 6from the seat4either by furtherstretching the stem 7 or distorting the valve head 6 so that it lifts from sealing engagementwith the valve seat 4.

The preferred embodiment illustrated in the drawing has been designed to operate at a pressure of7 p.s.i.This is achieved by varying the rubber mixfrom which the valve member is madewherebythe stem 7, when inserted in the valve body, exerts the required pressureto ensure thatthe valve head 6 will only lift from the seat 4 at a pressure of 7 p.s.i. It will be appreciated that byvarying the rubber mix, the tension exerted by the valve head on the valve seat can be varied to any required level but the required rubber mix would have to be calculated by trial and error.

Claims

1. A one way valve comprising a valve body provided with an inlet and an outlet, a valve seat adjacent to the outlet, a chamber connecting the valve seat to the inlet and a one-piece flexible valve member having a head and a stem portion extending therefrom, said stem being anchored to the valve body by means such that, in use, the head will only liftfrom the seatata predetermined pressure.

2. Avalve as claimed in claim 1 wherein the head has a sealing surface shaped to co-operatewith the valve seat, the stem portion extending through the chamber along its longitudinal axis.

3. Avalve as claimed in claim 1 or claim 2wherein the valve stem is anchored atthe end of the chamber remote from the valve seat.

4. Avalve as claimed in claim 3 wherein the end of the stem informed with a protruberance which is of a greaterdiameterthenthestemand is anchored in a hole in the end wall ofthe chamber.

5. A valve as claimed in claim 4wherein the protruberance is in the shape of an inverted cone wherebythe undersurface of said cone seats against the exterior end face ofthe valve body surrounding the hole.

6. Avalve as claimed in claim 4 or claim Swherein a tail extends from the protruberance coaxial ly with the stem.

7. A valve as claimed in any one ofthe preceding claims wherein the valve head is frusto-conical to provide an inclined surfaceto co-operate with a correspondingly shaped surface on the valve seat.

8. Avalveasclaimed in any one of claims 1-6 wherein the valve seat is a radially extending plane surface provided at one end ofthe chamber.

9. A valve as claimed in claim 8 whereínthe valve head includes a plane radially extending surface shaped to co-operate and seal with the radially extending valve seat surface.

10. Avalve as claimed in claim 8 orclaim 9 wherein the valve head includes a downwardly depending annular lip shaped to co-operate and seal with the radially extending valve seat surface.

11. Avalve as claimed in any one ofthe preceding claims wherein the chamber is coaxial with the valve stem and of a greaterdiameterthan said stem throughoutthe part of its length between the valve seat and where the inlet opens into said chamber.

12. Avalve as claimed in claim 11 wherein the inlet is a passageway which extends from the exterior of the valve bodyto the chamber, said passageway entering the chamber art a location spaced from the valve seat.

13. Avalve as claimed in claim 12 wherein additional inlet passageways extend from the exterior of the valve bodytothe chamber.

14. Avalve as claimed in any one of the preceding claims wherein the stem is stretched during insertion into the valve body and anchored in its stretched condition thereby pre-tensioning the valve head so that, in use, it lifts from the valve seat only at said predetermined pressure.

15. Avalve as claimed in any one of the preceding claims wherein said predetermined pressure is 7 p.s.i.

1 6.Avalve as claimed in any one of the preceding claims made from a natural or synthetic rubber material.

17. Avalve as claimed in any one of the preceding claims made from a synthetic plastics material.

18. A one way valve substantially as herein described with reference to the accompanying drawings.

19. Avalve membersubstantiaily as herein de- scribed and illustrated in the accompanying drawings.