GB2266132A

GB2266132A - Temperature-responsive mixing valve

Info

Publication number: GB2266132A
Application number: GB9208134A
Authority: GB
Inventors: Derek John Goldsmith
Original assignee: Aqualisa Products Ltd
Current assignee: Aqualisa Products Ltd
Priority date: 1992-04-13
Filing date: 1992-04-13
Publication date: 1993-10-20
Anticipated expiration: 2012-04-13
Also published as: GB2266132B; GB9208134D0

Abstract

A thermo-responsive mixing valve comprises a cartridge which is axially movable within a housing for controlling on/off and volume flow of water with the proportions of hot and cold flow through the cartridge to an outlet therefrom being controlled by a temperature-responsive member within the cartridge. With this construction, it is possible for a temperature- responsive valve to be utilised with a single control, rotation controlling the outlet temperature and reciprocating movement controlling the volume throughput and providing an on/off function. The cartridge comprises a shell 57 secured to a projecting operating member 76. The shell has inlet openings 53, 55 that can align with in lets 52, 54 in the valve housing. Axial movement of the shell controls the volume of fluid passing through the inlets. A wax-stat 60, which is adjustable by altering the loading of spring 68, is connected to flow proportioning element 62, for controlling the relative flows of hot and cold fluid through the inlet openings 53, 55. <IMAGE>

Description

TEMPERATURE-RESPONSIVE MIXING VALVE This invention relates to an improved temperature-responsive mixing valve and more especially to such a valve which can have a single lever control both for volume throughput and for temperature control.

Single lever control devices for taps and faucets have been known for many years whereby a single control member can be rotated and/or translated in order to provide for control, from one control member, of both the on/off and volume throughput and of the temperature of outlet flow. However, such prior devices have not been available for valves which include a temperature responsive means for automatically controlling the outlet flow to a preset temperature, despite variations in the temperature of the inlet water.

A principal object of the present invention is to provide a thermo-responsive mixing valve which can be adapted for single member control for controlling the volume of throughput and for controlling the variable temperature of the outlet.

According to the present invention, there is provided a thermo-responsive mixing valve comprising a housing provided with two inlet ports for hot and cold fluid, a cartridge slidably received in said housing and having inlet openings for hot and cold fluid and an outlet for mixed fluid, and temperature-responsive means in the cartridge for controlling the ratio of flow from the inlet openings to control the temperature of the outlet fluid, the slidable movement of the cartridge in the housing providing for selective communication between the inlet ports and the inlet openings to provide for on/off and volume flow control of fluids through the valve.

Preferably, the cartridge is linearly slidable in the housing to provide the on/off and volume throughput control with rotation of the cartridge providing for adjustment of the set point of the temperature-responsive means. In the preferred construction, the temperatureresponsive means is a wax-stat which are now available in quite compact forms and capable of giving control characteristics suitable for use with domestic hot water supplies, for example as used in wash-hand basins.

Preferably, in order to avoid temperature surges upon adjustment of the temperature-responsive means, a fluid damper is provided to damp initial movement of a temperature control element following adjustment of the set point of the temperature-responsive means.

Conveniently, such damping means can be a piston reciprocatable within a cylinder, such motion being damped by water needing to pass through a restricted passage from side to side of the piston.

The invention will be described, by way of example, with reference to the accompanying drawing, which illustrates in longitudinal section a thermo-responsive mixing valve embodying the invention.

In the single Figure of the drawings, there is shown a housing 50 which slidably receives a cartridge comprising a main body comprising a shell 57 secured at its right-hand end to a projecting operating member 76.

Inlets 52 and 54 for hot and cold water respectively are provided through the housing 50 for communication with inlet openings 53 and 55 respectively through the shell 57. A structural moulding 59 is provided within the shell with the shell and moulding preferably having been formed by moulding from plastics material. An outlet 56 for mixed fluid is provided from the cartridge.

Within the cartridge is provided a temperatureresponsive element, illustrated as the preferred wax-stat type of element, with the wax-stat element 60 being mounted between oppositely acting compression springs 66 and 68. A flow proportioning element 62 for controlling the relative flows of hot and cold fluid through the inlet openings 53 and 55 is connected by spokes to a central ring 64 secured to a member which itself is forced against the left-hand end of the wax-stat 60 by means of a compression spring 66 engaged between the ring 64 and an end portion of the shell 57.

The spring 68 engages the lip of a cup-shaped element 82 which itself engages a plunger 70 projecting from the right-hand end of the wax-stat 60. The righthand end of the spring 68 engages a stop member 80 which itself is rotatable within the right-hand end of the insert 59 portion of the cartridge. A recess is provided in the stop portion 80 to receive an L-shaped member 78 which projects through a slot extending part-way around the periphery of the right-hand end of the shell 57. The right-hand end of the shell 57 is itself closed by means of a control member or projection 76.

Secured to the wax-stat 60 is fluid damping means comprising a piston 72 reciprocatable within a cylinder 74, such movement being resisted by movement of fluid from one side of the piston to the other through restricted orifices in the piston.

The cartridge and housing so far described can be mounted directly within a tap or valve housing but preferably is mounted in an outer housing which itself is receivable in the tap, faucet, or other valve in which the mixing valve-is to be incorporated. As illustrated, the outer housing 84 slidingly and sealingly receives the housing 50 and the cartridge with the cartridge being retained therein by means of a nut 86, threaded on the right-hand end thereof, that nut having a radially inwardly projecting flange to encompass the projecting control member portion 76 of the shell 57. The radially outward end of the member 78 which projects from the shell is received within an axially extending slot in the outer housing 84 so as to hold the member 78 against rotation relative to the outer housing.

The outer housing 84 is provided with recesses 87 for the receipt of suitable seal rings for providing the required sealing when the outer housing is mounted within the tap or the like. The outer housing has ports aligned with the hot and cold inlet ports 52 and 54 to the main housing (50) and with the outlet (56) for mixed fluid from the cartridge (57).

In use of this mixing valve, the cartridge is axially movable within the housing 50 for providing an on/off action and for varying the flow throughput through the valve. Thus, as shown in the drawing, the valve is in its open position. This provides the minimum of impediment to flow from the inlet ports 52,54 to the inlet openings 53 and 55. If the control member 76 is now pushed to the left, it will slide within the housing 50 until the openings 53 and 55 are no longer aligned with the ports 52 and 54 so as to cut off inlet fluid flow to the openings. The size of the leftward movement of the cartridge will determine the proportion of volume of flow allowed from the inlet ports to the inlet openings. If the member 76 is rotated, it will rotate the cartridge relative to the member 80, and because of a threaded connection between the member 80 and the cartridge, such rotational movement of the cartridge will cause axial movement of the member 80 and thus will control the spring force exerted by the spring 68 against the cup 80 which bears against the plunger 70 of the wax-stat. As shown in the drawing, the valve is positioned with the cold water fully switched off and with maximum flow of hot water permitted. The position shown in the drawing with the cap 82 abutting against the member 80 is not one that will normally be achieved in practice and conventionally the wax-stat 60 will be floating between the spring support provided by the two springs.When so-floating, upon rotation of the member 76 to cause leftward movement of the member 80, there will be an increase in spring pressure urging the wax-stat 60 to the left, such that the closing or obturating element 62 will itself tend to move to the left to restrict flow through the opening 53 and to reduce obstruction to the inner opening 55 with the consequence that there will be a reduction of hot flow and an increase of cold flow to reduce the temperature of the outlet mixture. The damping piston 72 will damp such initial movement under the influence of the spring pressures, so as to reduce the tendency for a surge of too cold liquid to be passed before the wax-stat has a chance to adjust for the required outlet temperature. This effect is particularly important when adjusting to increase the temperature of outlet water since one does not want a surge of very hot water which could scald or hurt the user of the valve, if subjected, however temporarily, to such water at that excess temperature.

As can be seen from the Figure, suitable 0-rings are provided so that when the cartridge is moved fully to the left, the inlet opening 53 will be separated from the inlet port 52 by an O-ring seal, the inlet opening 55 will be located between two seals whereby there is no communication between that opening and either of the inlet ports, a further seal ring at the right-hand end of the housing 50 preventing direct communication between the cold inlet port and the outlet for mixed fluid.

Claims

1. A thermo-responsive mixing valve comprising a housing provided with two inlet ports for hot and cold fluid, a cartridge slidably received in said housing and having inlet openings for hot and cold fluid and an outlet for mixed fluid, and temperature-responsive means in the cartridge for controlling the ratio of flow from the inlet ports to control the temperature of the outlet fluid, the slidable movement of the cartridge in the housing providing for selective communication between the inlet ports and the outlet openings to provide for on/off and volume flow control of fluids through the valve.

2. A mixing valve according to claim 1, wherein the cartridge is linearly slidable in said housing.

3. A mixing valve according to claim 1 or 2, wherein the cartridge is rotatable to provide temperature adjustment of temperature-responsive means.

4. A mixing valve according to any preceding claim, wherein the temperature-responsive means comprises a wax-stat.

5. A mixing valve according to any preceding claim, wherein a flow proportioning element is slidable in said cartridge under the control of the temperatureresponsive means inversely to vary the obturation of the inlet openings.

6. A mixing valve according to claim 5, wherein the flow proportioning element is spring-biased towards one end of the temperature-responsive means, whereby it is movable against said spring-bias upon expansion of the temperature-responsive means upon an increase in the temperature of the mixed fluid.

7. A mixing valve according to any preceding claim, wherein a support for a spring applying a bias to urge the temperature-responsive means in a direction to close the hot fluid inlet opening is provided within the cartridge, a threaded connection being provided between the spring support and the cartridge, whereby relative rotation of the support and the cartridge will vary the spring bias and thus the temperature setting of the temperature-responsive means.

8. A mixing valve according to claim 7, wherein means are provided for holding said support against rotation, whereby rotation of the cartridge will provide temperature control and axial movement of the cartridge will provide on/off and variable volume fluid control of the valve.

9. A mixing valve according to any preceding claim, wherein the housing is provided with an outer housing for fitting within a tap or faucet body or the like.

10. A mixing valve according to claim 9, wherein a connection is provided between the outer housing and the spring support for holding the spring support against rotation, relative to the outer housing.

11. A mixing valve according to any preceding claim, wherein a threaded flanged sleeve is provided for retaining the cartridge in the outer housing.

12. A mixing valve according to claim 5, or any one of claims 7 to 11, when appendant thereto, wherein fluid damping means are provided for damping movement of the flow proportioning element in the cartridge.

13. A mixing valve according to claim 12, wherein the fluid damping means comprises a piston movable within a fluid-containing cylinder.

14. A mixing valve according to claim 13, wherein the damping fluid is water.

15. A mixing valve according to any one of claims 12 to 14, wherein the damping means is carried by the temperature-responsive element.

16. A thermo-responsive mixing valve constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.