GB2253463A

GB2253463A - Valve cartridge

Info

Publication number: GB2253463A
Application number: GB9104654A
Authority: GB
Inventors: Barry Raymond Sherratt; Howard William Parry; John Joseph Jones
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-03-05
Filing date: 1991-03-05
Publication date: 1992-09-09
Anticipated expiration: 2011-03-05
Also published as: GB9104654D0; GB2253463B

Abstract

A valve cartridge (1) comprises a generally cylindrical body (3) which is adapted to be screwed into a conventional tap (9). A bore (5) extends through the body (3) with a valve closure member (21) being spring biassed against a valve seat (23), provided towards one end of said bore (5). An elongate actuator rod (43) extends through a reduced diameter section (29) of said bore (5) and is engageable at one end with the valve closure member (21) and at the other end with an actuator member (35) which projects out of the other end of said bore (5). The actuator rod (43) extends sealingly through an annular seal (31) located at the end of the reduced diameter section (29) of the bore (5) nearest to the valve closure member (21) and a lateral passage (27) extends through the body (3) from the region of the bore (5) between the annular seal (31) and the valve closure member (21). <IMAGE>

Description

DESCRIPTION IMPROVEMENTS RELATING TO TAPS The present invention relates to a tap unit for use in a tap for controlling the flow of a fluid.

In particular, the present invention relates to a tap unit for use in a tap for controlling the flow of hot or cold water from a supply. Certain known water taps have a control knob which is manually rotatable to either tighten a sealing washer onto a valve seat to stop the water flow, or to release the washer and allow the water to flow. Instead of this screw action control knob and washer arrangement, another known type of water tap has a press action with the control knob being spring-biassed towards an extended closed position. Thus, by depressing the control knob a flow of water is obtained and the mere release of the control knob allows the tap to close, various types of delay mechanism being provided so that the tap closes over a short period of time after release.

With the known and widely used screw action water taps it is commonplace for such taps to be left open with the water running by both young and old, especially in public conveniences. Clearly, this is a waste of water and it is highly desirable to change such taps to press action taps which automatically close on release. However, press action taps are relatively expensive and this prevents taps being replaced, especially in public locations.

The aim of the present invention is to provide a tap unit wherein the top part of a screw action tap, which part is normally unscrewable to enable the sealing washer to be replaced, can be simply unscrewed, and the tap unit of the present invention substituted to convert the tap to a press action tap.

According to the present invention there is provided a tap unit for use in a tap for controlling the flow of a fluid, the tap unit comprising a generally cylindrical body which is adapted to be screwed into a tap, a bore extending through said body with a valve closure member being spring biassed against a valve seat, provided towards one end of said bore, an elongate actuator rod extending through a reduced diameter section of said bore and being engageable at one end with the valve closure member and at the other end with an actuator member which projects out of the other end of said bore, the actuation rod extending sealingly through an annular seal located at the end of the reduced diameter section of the bore nearest to said valve closure member, a lateral passage extending through said body from the region of the bore between the annular seal and the valve closure member.

A tap unit constructed according to the present invention can thus be screwed into a conventional tap in place of the usual top part of a conventional screw action tap, water pressure besides the spring bias holding the valve closure member which is preferably a ball, against the said valve seat which is preferably formed by a resilient O-ring seal, the tap thus being closed. By depressing the actuator member, the actuator rod is slid axially through said annular seal which is also preferably a resilient O-ring seal, the actuator rod lifting the ball off the valve seat and allowing water to flow past the ball and valve seat and then out of the body via said lateral passage, the said annular seal preventing the flow of water further along said bore. On releasing the actuator member water pressure and the said spring bias move the ball towards the valve seat to close the tap.However, as the water pressure is acting on said annular seal this annular seal is deformed to frictionally grip the actuator rod and resist snap closure of the ball on the valve seat, such snap closure being undesirable as it would result in shock waves through the system due to the impact of the ball on the valve seat. The tap is thus closed relatively slowly, the provision of the resilient O-ring valve seat also assisting in the avoidance of such shock waves. By relying on the resiliently deformable annular seal to provide the frictional grip on the actuator rod, the frictional grip automatically adapts to the water pressure so that with higher water pressures the necessary greater frictional grip to resist snap closure is automatically produced.

Preferably a flow control device is also located in the said bore of the tap unit body, this flow control device maintaining the rate of water flow substantially constant irrespective of the supply pressure. One suitable proprietary flow control device is disclosed in British Patent Specification No.1,350,846.

With the tap unit screwed firmly into the lower part of the conventional screw action tap, a control knob may be secured to the said actuator member to facilitate operation.of the tap unit. Preferably this control knob has a recess which fits over the actuator member with gripping means provided on the central knob and/or actuator member to secure the control knob to the actuator member. Alternatively an axial projection of the knob may engage in a recess in the actuator member. Preferably the gripping means is such as to prevent the knob from being removed after it has been located in position, e.g. sharks teeth type projections form the gripping means, the knob extending down over the screw thread connection between the tap unit and the said lower part of the tap. In this way the tap is tamper-proof, the unit having to be destroyed to be removed.

According to a further aspect of the present invention there is provided a control knob for a tap, comprising a body member which has a recess into which an actuator member of a tap unit can be engaged, gripping means being provided for securing the knob to the actuator member.

Preferably the control knob is provided with sharks teeth type projections on its inside surface, i.e. the surface of the recess, which projections bite into the surface of the actuator member to thus grip the actuator member and prevent removal.

Alternatively an axial projection of the knob may project from the base of the knob recess and engage into a recess in the actuator member, suitable gripping means securing the axial projection in the actuator member recess.

The present invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Fig.1 is a cross-sectional view through a tap incorporating a preferred embodiment of a tap unit constructed according to the present invention, with the tap unit closed; and Fig.2 is the same cross-sectional view, to an enlarged scale, with the tap unit in an open condition.

The preferred embodiment of tap unit generally designated 1, constructed in accordance with the present invention and illustrated in the accompanying drawings, comprises a generally cylindrical body 3 made of a suitable plastics material, the body having an axially extending through bore 5 with part of the external surface of said body being threaded as at 7, the thread 7 enabling the unit 1 to be firmly secured in the lower part 9 of a conventional water tap.

For manufacturing purposes the body 3 is made of two sections 11,13 which are bonded together. The through bore 5 has a number of different diameter sections which are described hereinafter. As illustrated, the lowermost section 15 of the bore 5, formed in body section 11, houses a flow control device 17 which is designed to maintain the rate of water flow substantially constant irrespective of the supply pressure. Such a flow control device is disclosed in British Patent Specification No.1,350,846. Engaging on the flow control device 17 is a spring 19, the spring 19 biassing a valve closure member in the form of a ball 21, against a valve seat formed by a resilient O-ring seal 23 which is located on the shoulder formed between section 15 of the bore 5 and the adjacent reduced diameter bore section 25 formed in body section 13.A lateral passage 27 extends from bore section 25 through body section 13 to open to the outside of the tap unit 1. Bore section 25 connects with a further reduced diameter section 29 of the bore 5 with a resilient annular seal in the form of an O-ring 31 being located on the shoulder defined between said bore sections 25 and 29, the purpose of which seal is described later. This further reduced diameter bore section 29 connects with an enlarged diameter section 33 of the bore 5, which enlarged diameter section 33 opens out at the upper end of the body 3 as illustrated. An actuator member 35 extends coaxially within the bore section 33 and has a recess 37 in its outer periphery, a pin 39 extending through the wall of body section 13 and engaging in the recess 37 to limit the available axial movement for the actuator member 35.The upper part of the actuator member 35 as illustrated in the accompanying drawings, projects out of the bore section 33 and has an enlarged diameter, a control knob 41 being secured thereto as will be described later. The lower part of the actuator member 35 engages one end of an actuator rod 43 which extends through bore sections 25,29 and 33, the actuator rod 43 being a snug though axially slidable fit in O-ring 31, with the other end of the actuator rod 43 being engageable with the said ball 21.

With the tap unit 1 installed in a tap 9 and in the closed position ås illustrated in Fig.1 of the accompanying drawings, the ball 21 is held by both spring 19 and water pressure against O-ring seal 23.

However, by depressing the control knob 41, actuator member 35 is moved downwards in bore section 33, moving actuator rod 43 also downwards, lifting ball 21 off O-ring seal 23 and allowing water to pass into bore section 25 and out of the tap unit via lateral passage 27. Resilient O-ring seal 31 grips the actuator rod 43 and prevents water from passing further along the bore 5. Further, the greater the water pressure, the greater the deformation of resilient O-ring seal 31 against the actuator rod 43, and thus the greater the frictional grip of O-ring seal 31 on the actuator rod 43. The seal 31 thus adjusts automatically to provide an efficient water seal irrespective of the water supply pressure.

Further, when the control knob 41 is released both spring 19 and the water pressure move the ball 21 back to the closed position of Fig.1, and the frictional grip of seal 31 on the actuator rod 43 resists this return motion, thereby slowing closure of the tap and preventing any snap closure and resultant shock waves through the water system.

To install the above described tap unit 1 it is merely screwed tightly as an integral unit, into the lower part 9 of a conventional tap. Then the control knob 41 which has a recess 45, is located over the tap unit 1, the wall 47 of the control knob extending down over the screw connection 7. The inside of wall 47 is provided with gripping means in the form of sharks teeth barbs 49 which bite into and grip the periphery of the actuator member 35 when the control knob 41 is pressed down onto the tap unit 1 during initial installation. Thus the tap cannot be disassembled without being effectively destroyed, thereby making the tap substantially tamper proof. Alternatively, if desired, such a control knob can be used with other appropriate tap constructions. Further, with a tap unit constructed according to the present invention any other type of known control knob attachment, e.g.

a screw attachment, can of course be used.

The present invention thus provides a modular tap unit which can enable a conventional screw action tap to be quickly and easily modified to a press action tap, with the facility of a control knob which renders the tap substantially tamper proof.

Claims

1. A tap unit for use in a tap for controlling the flow of a fluid, the tap unit comprising a generally cylindrical body which is adapted to be screwed into a tap, a bore extending through said body with a valve closure member being spring biassed against a valve seat, provided towards one end of said bore, an elongate actuator rod extending through a reduced diameter section of said bore and being engageable at one end with the valve closure member and at the other end with an actuator member which projects out of the other end of said bore, the actuation rod extending sealingly through an annular seal located at the end of the reduced diameter section of the bore nearest to said valve closure member, a lateral passage extending through said body from the region of the bore between the annular seal and the valve closure member.

2. A tap unit as claimed in claim 1, in which at least a portion of the axial length of the periphery of the cylindrical body is threaded so that the body can be screwed into a conventional tap.

3. A tap unit as claimed in claim 1 or claim 2, in which the valve closure member is a ball and the valve seat is formed by a resilient O-ring seal fixedly located within said bore.

4. A tap unit as claimed in any one of claims 1 to 3, in which the said annular seal takes the form of an O-ring which is, in use, resiliently deformable under the effect of water pressure, to thus increase the frictional grip of the O-ring on the actuator rod.

5. A tap unit as claimed in any one of claims 1 to 4, in which a resilient O-ring is located around the actuator rod and against the wall of said bore, said O-ring being movable with said actuator rod.

6. A tap unit as claimed in any one of the preceding claims, in which a flow control device for maintaining the rate of water flow substantially constant irrespective of the water supply pressure, is located in the said bore of the tap unit body.

7. A tap unit as claimed in any one of the preceding claims, in which a control knob is secured to the said actuator member to facilitate operation of the tap unit.

8. A tap unit as claimed in claim 7, in which the control knob has a recess which fits over the actuator member with gripping means provided on the control knob and/or actuator member to secure the control knob to the actuator member.

9. A tap unit as claimed in claim 8, in which the gripping means are in the form of sharks teeth type projections which prevent the control knob from being detached once it has been attached to the actuator member.

10. A tap unit as claimed in any one of claims 7 to 9, in which the control knob extends down over the screw threaded connection between the tap unit and the tap when the tap unit has been secured to the tap and the control knob has been attached to the actuator member, the combination of the tap unit and tap thus being tamper proof.

11. A tap unit for use in a tap for controlling the flow of a fluid, constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.