GB2082732A

GB2082732A - A Replacement Valve Assembly for a Liquid Flow Control Device

Info

Publication number: GB2082732A
Application number: GB8117870A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-06-12
Filing date: 1981-06-11
Publication date: 1982-03-10

Abstract

A replacement valve assembly for a liquid flow control device, said assembly comprising a seat and a valve member to cooperate with the seat, the seat has a conical seating surface which is on the exterior of the seat and a through bore, the valve member has an annular recess with an angled face to co-operate with the seat conical surface to form a liquid tight joint and another angled face which will in the event of the valve member being forced onto the valve seat after the liquid tight joint has been formed then seal against the corner where the bore exists from the seat to provide a secondary seal and also prevent the valve member being forced harder into contact with the seat. <IMAGE>

Description

SPECIFICATION A Replacement Valve Assembly for a Liquid Flow Control Device This invention relates to valves as used in the regulation of the flow of liquid through a flow controlling device, an example of which is a water tap.

Hitherto the usual method of controlling the flow through a tap has been to force a flat surface of a washer of material which is soft, compared to the nature of the material from which the tap was made, onto a flat seat in the tap body and in that way interrupt the water passage through the tap.

Afterfontinual usage the washer became worn and had to be replaced. This was due in part to the difference in hardness between the two materials sealing one against the other. Another reason was that particles of abrasive material, commonly entrained in the water flow, ocassionally lodged on the flat sealing surfaces of the tap washer and the seat in the tap body.

When the washer was forced onto the seat these particles became embedded in the washer and in subsequent closing operations the seal became less efficient. Often the seat in the tap body became very badly worn and unserviceable due to the scoring of the seat by the abrasive particles.

To overcome the above problem there have been several attempts to replace the conventional system, as explained above, by replaceable valve assemblies that were inserted into the tap and provided a removable seat member and a cooperating and removable valve member of compatible material. This avoided the problem of wear due to different materials. In addition, in one currently available assembly, there was an attempt to achieve a seal which overcame the abrasive particle embedding problem. This involved forcing a tapered nose of the valve member into the end of a port extending through the seat member. This arrangement, whilst having short term reliability and effectiveness, has several attendant problems. For example, the sealing contact is line contact in that a sharp corner, where a bore exited into a flat face, is forced into engagement with the tapered surface of cone.Eventually the seal therebetween became less efficient with the result that the sealing pressure had to be increased which in turn accelerated the wear pattern. Secondly, the pressure applied to the seat was in the form of a wedge action which had the effect that the diameter of the line of sealing contact was continually being forced outwardly and enlarged.

Over a long period this too led to a lessening of the efficiency of the valve.

This invention has been devised to overcome both of the above problems. In a preferred embodiment there is a primary as well as a backup or secondary sealing system which can be brought into operation to double up on the primary sealing system. At the same time it will prevent excessive closing pressure being applied to the valve members.Accordingly the present invention in its broadest form comprises a replacement valve assembly for a liquid flow controlling device, said assembly comprising a valve seat and a valve member, the valve seat comprising a body with a bore extending from one end to the other of the body, a part of which bore at one end of the body is of circular cross-section, a conical sealing surface on said one end of said body concentric with said bore part, an annular land between said sealing surface and said bore part, said body being externally adapted to be mounted in said device so that the liquid flow path therethrough includes said bore; said valve member including a head on a stem, an annular Vee section sealing groove providing an inner and an outer sealing face both concentric with the stem and located in a surface of the head that lies at right angles to the axis of the stem, the included angle between the outer sealing faces of the Vee of the sealing groove being substantially the same as the included angle of said conical sealing surface and the dimensions of the sealing groove and said sealing surface being such that when engaged one with the other the bore is sealed off.

A presently preferred embodiment of the invention will now be described by reference to the accompanying drawing which is a crosssection through a tap in which the replaceable valve assembly of this invention is mounted.

There is a'tap body 1 with an inlet 2 and an outlet 3 separated by a partition wall 4 through which there is a port 5. The tap body 1 has a boss 6 into which is threaded a holder 7 for a valve operating spindle 8 which is in turn threaded into the holder 7. There is a seal 9 to prevent escape of liquid through the valve operating assembly.

The spindle has a central blind hole 10 which is aligned with the port 5.

The replacement valve assembly comprises a valve seat 11 and a valve member 12. The valve seat comprises a body 13 with an enlargement 14 at one end to provide a head with an underface 1 5 which acts as a shoulder to engage against the surface 16 of the wall 4 around the port 5. At the other end the body 13 has an encircling lip 1 7 to retain the body 13 in the port 5. The lip 17 may be deleted if the body 13 has a diameter such that it is an interference fit in the port 5. Alternatively, the lip 1 7 could be discontinuous and in the form of one or more lugs to act as retainers where the diameter of the body 1 3 is such that there is no frictional grip of the body 13 in the port 5. The lip 17 is of such size that it can be forced resiliently through the port 5.

The head 14 has its outer end chamfered to provide a tapered nose 1 8 with a land 1 9 between the chamfer and a bore 20 extending through the body 13. The bore 20 can be parallel or of any shape provided that the end part adjacent the land is of circular cross-section. The valve member 21 comprises a head 22 of circular shape with a stem 23 extending from the back face at right angles to the axis of the stem and located in hole 10 of the spindle as a free sliding fit. The front face of the head 22 is provided with an annular groove 24 of Vee cross-section.The outer sealing face 25 of the groove has an included angle the same as or substantially the same as the included angle of the nose 18 and the dimensioning of the parts is such that when engaged one with the other the face 25 of the valve member bears on the angled face of the nose 1 8 to provide angled co-operating sealing surfaces.

The dimensioning of the components is also such that the inner face 26 of the groove 24 is arranged to lie closely adjacent the corner 27 where the bore 20 exits to land 1 9 when the faces 25 and 18 are in engagement. It will be noted that a pocket 28 is formed between the land 1 9 and the apex of the groove 24. This serves to trap and temporarily hold any foreign matter that may be conveyed by the liquid into the valve assembly. At a subsequent opening of the valve any deposit in the pocket 28 is flushed away. It will also be noted that the angle of the faces 25 and 18 prevents any build up of foreign materials on those faces and thus the problem of abrasive particles becoming embedded in the sealing faces is avoided.

In operation, as the spindle 8 is screwed into the tap the face 29 at the end of the spindle bears on the rear face 30 of the head 22 to urge the faces 25 and 1 8 into contact. As pressure is applied sealing is achieved. This arrangement would be satisfactory for normal purposes as there is a broad sealing zone ensuring good sealing action. The faces are inclined so there is no possibility of grit deposit thereon and as the face 25 encircles the nose 18 so there is no distortion of the latter. If however a very heavy handed person turned off the tap it would be possible to cause the face 25 to deflect, bearing in mind that it is proposed to form the parts from a plastics material. To prevent this happening there is provided the secondary sealing means.

This involves the face 26 of the Vee groove 24 engaging the corner 27 of the bore 20. Normally this engagement will not occur and the face 26 and the corner 27 will be spaced one from the other. It will be understood that once the double seal, as detailed above, has been achieved the whole valve assembly is "locked up" thereby preventing any additional operator pressure being effectively applied.

Claims

1. A replacement valve assembly for a liquid flow controlling device, said assembly comprising a valve seat and a valve member, the valve seat comprising a body with a bore extending from one end to the other of the body, a part of which bore at one end of the body is of circular cross-section, a conical sealing surface on said one end of said body concentric with said bore part, an annular land between said sealing surface and said bore part, said body being externally adapted to be mounted in said device so that the liquid flow path therethrough includes said bore; said valve member including a head on a stem, an annular Vee section sealing groove providing an inner and an outer sealing face both concentric with the stem and located in a surface of the head that lies at right angles to the axis of the stem, the included angle between the outer sealing faces of the Vee of the sealing groove being substantially the same as the included angle of said conical sealing surface and the dimensions of the sealing groove and said sealing surface being such that when engaged one with the other the bore is sealed off.

2. A valve assembly as claimed in claim 1 wherein the dimensioning of the sealing groove and the sealing surface and the width of said land and the diameter of the bore is such that when the sealing surface is engaged with the sealing groove outer face the sealing groove inner face lies closely adjacent a sealing corner at the intersection of the bore with the annular land.

3. A replacement valve assembly as claimed in claim 1 or claim 2 wherein the external adaption of the valve seat body provides a tubular part which at one end terminates in a shoulder which is an underface of a head on which said conidcal sealing surface is formed and at the other end in external lip means to retain the tubular part in a bore in said device.

4. A replacement valve assembly for a liquid flow controlling device, said assembly comprising a valve seat and a valve member, the valve seat comprising a body with a bore extending from one end to the other end thereof, a part of which bore at one end of the body is of circular cross-section, concentric sealing surfaces at said one end of the body both concentric with the axis of said bore part, an annular land between said concentric sealing surfaces, the valve seat body being adapted to be mounted in said device so that the liquid flow path through the device includes said bore; said valve member including an annular Vee section groove with inner and outer sealing faces, the dimensioning of the groove and the concentric sealing surfaces and the width of the land being such that when the valve member is engaged with the valve seat the outer sealing face of the Vee groove is in face to face engagement with the outer of said concentric sealing surfaces and the inner sealing face of the Vee groove lies in close proximity to the inner of said concentric sealing surfaces.

5. A valve assembly as claimed in claim 4 wherein the valve seat body includes a tubular portion adapted to be inserted and retained in a port in the liquid path through the flow controlling device.

6. A valve assembly as claimed in claim 5 wherein the tubular portion has a shoulder at one end and a retaining means at the other end, the material of manufacture of the valve seat body and the size of the retaining means being such that the retaining means whilst larger than the size of the port can be forced resiliently through said port.

7. A valve assembly as claimed in claim 4, 5 or 6 wherein the valve member comprises a body with two parallel faces, the annular vee section groove is in one of said faces and there is a stem projection normal from the other of said faces and the stem has a long axis that is co-incident with the centre point of the annular vee groove.

8. A replacement valve assembly as herein described with reference to the drawings.

9. A tap when fitted with a valve assembly as herein described.