GB2289746A - Mixing valve assembly - Google Patents

Abstract

A valve assembly for controlling a water supply, suitable for use in for example a shower system, which is fed by hot and cold water supplies, has pressure regulating valves 15, 16 that compensate for fluctuations in inlet water pressure such that the outlet temperature remains substantially constant, each valve also providing for complete cut-off of fluid flow. A control knob 14 is rotatable to adjust the compression of a spring 57 which bears on the closure members of the two valves 15, 16 via an intermediate plate 30, thus moving the closure members towards or away from their respective seats 35, 36. When the valves are open, the positions of the two closure members are controlled in response to prevailing water pressure acting in opposition to further springs 17, 18. In a modification (fig. 4, not shown) separate control knobs are provided for the two pressure regulating valves.

Description

Title: "Control Valve for Water Supply" Description of Invention The present invention relates to control means for water supply and is primarily but not exclusively concerned with valves to control water supply to showers.

Various different valve means are known for controlling water supply to showers and in a simple form may comprise a conventional flow control valve or tap, one on the cold water supply and the other on the hot water supply, each of which are suitably adjusted by the user to obtain the correct water temperature.

Control of the water temperature is quite difficult with such an installation, not only to obtain the desired water temperature in the first instance but also any variation in the pressure of supply, either of the hot or cold supply, will make readjustment once again necessary and in any installation where water pressure, and hence flow conditions, are likely to vary, such installations are not really suitable.

The above described method of water supply control may be incorporated in a mixer valve which usually considerably simplifies the initial adjustment.

However, such valves also suffer from the problem where, if there is a change in the water pressure of the hot or cold supply, the valve will once again require readjusting.

In order to overcome the problems of variation in the temperature of the supply of hot or cold water or for that matter a change in flow conditions, due to a change in pressure, thermostatically controlled valves are known which sense the temperature of the mixed water and in response to a change from a predetermined desired value, adjust the flow as necessary to once again achieve the desired temperature.

Some such valves are quite successful in their operation. However, inevitably there is a time lapse in the sensing of the incorrect temperature and readjustment of the valve and furthermore such valves, or at least those that operate successfully, are fairly intricate and hence expensive.

Whereas thermostatic valves are quite successful in dealing with changes in water temperature of the cold or hot water supply of the type that may occur in domestic environments where it is quite conceivable that if fed from a supply tank, the temperatures in both the cold and hot supply may vary, it is unusual for there to be a sudden change in the water temperature or pressure of supply since most properly arranged domestic systems have a dedicated supply, thermostatic valves can generally speaking cope quite adequately with slow variations in temperature.

Considerable problems however exist in installations where a change in temperature of the water at a shower head can almost instantaneously be caused by sudden variations in the pressure of supply of either the hot or cold supply or both.

Such variations are very common in installations where many users have access to the same supply, such a situation may occur in blocks of flats, mobile homes, touring caravans, boats or the like that are provided with shower installations and the speed of response of a thermostatic valve can sometimes be less than adequate.

It is an object of the present invention to provide valve means for controlling the supply of water that overcomes or minimises the problems mentioned above.

According to one aspect of the present invention, we provide first and second pressure regulating valves each comprising an inlet and an outlet, a movable member having first resilient biasing means acting thereon, said movable member being adapted to acted upon by fluid flowing from the inlet to the outlet in a manner to minimise fluctuations in pressure at the outlet due to fluctuations in fluid pressure at the inlet and wherein said valves are provided with manually operable means, operable to move the position of said movable member through the intermediary of second resilient biasing means to different positions against the resilient bias provided by said first resilient biasing means and hence to permit of an increase or decrease in the flow of fluid through said valve, and wherein said manually operable means is movable to a position in which the movable member is held in sealing engagement with a seat to prevent fluid flow from said inlet to said outlet, and wherein the inlet of said first valve is adapted for connection to a cold water supply and the inlet of said second valve is adapted for connection to a hot water supply and wherein the outlets of said first and second valves are connected together.

Each of said valves may be provided with a separate manually operable means or in an alternative form a single manually operable member may be provided, said single manually operable member being operative to move the position of the movable member of each valve.

In the case where a single manually operable means is provided, it may be preferred that one of said valves is caused to open before the other and the second resilient biasing means provided in said first valve may be different from the second resilient biasing means provided in said second valve.

Alternatively, other means may be provided such as the shape or position of an intermediary member movable by said manually operable means to cause operation of the movable member of each valve such that one of the movable members is moved before there is any movement of the other.

It will be appreciated that, depending upon the water supply system to which the valve means is a part, if for example there was a good source of hot water, it may be preferred to initially operate the valve means supplying cold water so as to prevent the possibility of someone being scalded through a supply of water that was too hot so that when the manually operable means is first initiated, cold or cool water is supplied, the temperature gradually increasing as the manually operable means is opened and an increase in hot water is allowed to flow through the valve means.

In other installations where the supply of hot water is such that the temperature could never be hazardous it may be preferred to initially allow supply of hot water to ensure that there is always water of sufficient temperature for showering, or washing dishes etc., and further operation of the manually operable means may then cause an increase in supply of cold water where it is desired that the temperature of a lower water is supplied to whichever installation the valve means is fitted.

The supply of water through the pressure regulating means for both forms of supply ensures that where the pressure of the water supply, whether hot, cold or both, is inclined to fluctuate, the valve means is adapted to maintain the temperature of the water substantially constant.

The invention will now be described in more detail by way of example only with reference to the accompanying drawings, wherein: FIGURE 1 is a section through one embodiment of valve means of the present invention; FIGURE 2 is a plan view of the embodiment shown in Figure 1; FIGURE 3 shows an installation of a valve as shown in Figures 1 and 2; FIGURE 4 is a section through a second embodiment of the invention.

Referring first to Figures 1 and 2, a first embodiment of the valve means is shown of the type where there is a single manually operable means adapted to operate both the first and second pressure regulating valves.

The valve, generally indicated at 10, has an inlet 11 for connection to the hot or cold supply and for the sake of description of the operation of the valve, it will be assumed that the inlet 11 is connected to the cold supply and a second inlet 12, which in this case will be connected to the hot water supply.

An outlet 13 is common to the outlets of both pressure regulating valves and hence, assuming both valves are open, will be for a mixture of hot and cold water.

The valve 10 is provided with manually operable means in the form of a wheel 14.

The valve means comprises a pair of identical pressure regulating valves, the pressure regulating valve generally indicated at 15 controlling the supply of cold water and the pressure regulating valve generally indicated at 16 controlling the supply of hot water. The only difference in the two valves 15 and 16 may be the strength of the second resilient means which in the case of the pressure regulating valves 15 and 16 comprise helical springs 17 and 18 respectively. It may be that in some cases one of the springs 17 or 18 is stiffer than the other.

Referring first to the cold water pressure regulating valve 15, the inlet 11 communicates with a chamber 19 in which is situated a movable member, hereinafter referred to as a piston 20. The piston 20 has a lower annular part 21 and is secured to the body 22 of the valve via an annular impervious but flexible membrane 23 which permits of some limited movement of the piston. A resilient sealing member is provided at 24 which provides a seal between the piston 20 and cylinder 25.

The piston 20 is provided with an upper spigot like part 26 having an annular seal 27 and an end part 28 which seats in a recess 29 in a plate like member 30.

The spigot like part 26 is provided with an inverted cup 31 in which a resilient sealing member in the form of a washer 32 is provided. the cylinder 24 is provided at its upper end with a valve seat 35 that is adapted, when the piston 20 is in a certain position, to make sealing engagement with the washer 32 to prevent any flow of fluid from the inlet 11 to the outlet 13.

The pressure regulating valve 16 is identical in all respects with the possible exception of the spring rating of the second resilient means 18 which may differ from the second resilient means 17.

The inlet 12 communicates with chamber 40 surrounding the piston 41 which is secured to the body 22 via an impervious diaphragm like member 42, an annular resilient seal 43 being provided to prevent flow communication between the annular chamber 40 and the outlet 13.

The piston 41 carries an upper spigot like part 44 provided with an inverted cup like member 45 carrying a sealing washer 46. The cylindrical like member 47 in which the piston 41 is located is provided with a valve seat 36 adapted to be capable of making sealing engagement with the washer 46 to prevent flow of liquid between the inlet 12 and the outlet 13.

The upper end 48 of the spigot like member 44 is located in a cup like depression 49 provided in plate like member 30.

The manually operable wheel 14 is connected to a spindle 50 which in turn is located by a circlip like member 51 to the body 22 in a manner such that the spindle may rotate about its longitudinal axis relative to the body but axial movement is prevented.

The spindle 50 is provided with a helical thread form 53 which is engaged in another helical thread form 54 on collar 55. The collar 55 which is of annular configuration has a bearing surface 56 which engages with one end of first biasing means in the form of a helical spring 57, the other end of which is located on the plate like member 30.

The arrangement is such that movement of the wheel 14 in a clockwise direction will cause downward movement of the collar 55 which in turn compresses spring 57 and increases the pressure applied by plate like member 30 on to spigots 26 and 44 of the pressure regulating valves.

Acting in an opposite direction to the first biasing means 57 are second biasing means 17 and 18, one for each of the pressure regulating valves, which comprise helical springs one end bearing on the body 22 and the other end being located in recesses 37 and 39 in pistons 20 and 41 respectively.

If the wheel 14 is rotated in an anti-clockwise direction, the downwards pressure on plate like member 30 will be reduced or removed and the pistons 20 and 41 will be allowed to move in an upwards direction under the biasing of secondary biasing means or springs 17 and 18.

A gap may then appear between valve seats 35 and washer 32 and valve seat 36 and washer 46 thereby creating a fluid flow path between inlet 11 and outlet 13 and inlet 12 and outlet 13.

Dealing first with the first pressure regulating valve 15, water may flow through the inlet 11 into chamber 19, through the gap between valve seat 35 and washer 32 into the chamber 60 and towards outlet 13. In the case of valve 16 water may flow through inlet 12 into chamber 40 through a gap now existing between valve seat 48 and washer 46 into chamber 61 and hence to outlet 13. If there is an increase in pressure at, for example, inlet 11 then the pressure on diaphragm 23 and its associated annular holding member 63 will increase, this will tend to move the piston in a downwards direction against the bias of spring 17 hence closing or tending to close the gap existing between valve seat 35 and washer 32 and hence control the fluid flow to immediately counteract the increase in flow that might have been expected to be generated because of the rise in pressure.

Similarly, a reduction in the pressure which would be expected to give a reduced flow will be compensated by a reduction in pressure on the other side of diaphragm 23 and associated annular holding member 63 which will have the effect of increasing the passageway between the valve seat 35 and washer 32 and enhance or increase the cross-sectional area of the fluid flow passage so as to maintain the flow rate substantially constant.

The operation of the second pressure regulating valve 16 is identical.

Depending on the nature and/or temperature of the two water supplies to be mixed by the valve means, it may be that the natural pressure of one supply is much greater than the other, in which case the valve may be particularly adapted to suit circumstances and, for example, the bias provided by springs 17 and 18 may differ from each other.

Alternatively, the recess 29 may differ from the recess 49 so that one of the valves is caused to open more than the other and as a still further alternative, the fluid flow passageways in each of the regulating valves may differ.

Baffle means may be provided, either in the valve itself or attached to the valve.

It is envisaged for example, that restriction may be provided with holes to permit of fluid flow from or to the valve, the size of the holes to or from each valve differing from the other.

Referring now in addition to Figure 3, a valve as shown in Figures 1 and 2 is shown installed and it is envisaged that the body 22 of the valve would be installed behind a surface 64 which could, for example, be a wall of a shower cubicle or the like thus the only part of the valve projecting into the cubicle is the wheel 14.

It is further envisaged that a switch means, such as a microswitch (not shown) may be incorporated in the valve, the microswitch being operated by, for example, the plate member 30 or at least movement thereof so that as soon as there is any movement of the wheel 14 to turn on the valve, and hence movement of plate member 30, the microswitch is operated which in turn can be operative to switch on heating means such as an instantaneous electrical heater or gas heater and/or turn on pumps to energise the water supply and in some installations may also be responsive to switch on a pump to clear away waste water.

An electrical lead 65 is shown which would be connected to the microswitch and the other end of which would be connected to relay means and/or whatever equipment it was desired to operate in response to movement of plate member 30.

As an alternative, where there is always some pressure on the cold or hot water supply and, it is necessary to cause energisation of some piece of equipment when it is desired to use the shower, a flow switch may be incorporated either in a supply pipe to the valve or possibly in the valve itself.

Referring now to Figure 4, an alternative embodiment is shown and in this case the pressure regulating valves controlling the supply of both hot and cold water are provided with separate manually operable means.

The valve means 70 comprises a first pressure regulating valve 71, a second pressure regulating valve 72 mounted in a common body 69.

The first pressure regulating valve 71 comprises a piston like member 73 capable of limited sliding axial movement within a cylinder 74, the lower of end of the piston 73 having an annular seal 75 and being secured to the body 69 via an annular diaphragm and supporting member 76. The other end of the piston 73 has an end part 77 which carries a resilient washer 78.

First resilient means in the form of a helical spring 79 bears on the end part 77, the other end of the spring 79 bearing on surface 80 of a carrier member 81.

The carrier member 81 is in the form of an annulus having an internal thread form in the form of a helical thread 82 which engages with a corresponding helical thread 83 formed on the outer surface of a spigot 84.

The spigot 84 is secured by a circlip type member 85 to prevent axial movement relative to the body 69 but capable of rotational movement about its longitudinal axis. Secured to the spigot 84 is a manually operable member in the form of a wheel 86. The arrangement is that rotational movement of the wheel 86 will cause movement in an axial direction of carrier member 81 which in turn increases or decreases the pressure applied via spring 79 on the piston 73.

An opposite force on the piston 73 is provided by second resilient means in the form of a helical spring 87 one end of which bears on the body 69 and the other end on end surface 88 of a recess formed in the piston 73.

The construction of the pressure regulating valve 72 is identical and hence a detailed description of the components is not necessary.

The pressure regulating valve 71 has an inlet 90 and the valve has an outlet 91. The valve 72 has an inlet 92.

The cylinder 74 in which the piston 73 is located has at its upper end a valve seat 93 and, when the wheel 86 is rotated in a clockwise manner, the valve seat 93 comes into contact with a washer 78 and flow communication between the inlet 90 and the outlet 91 through valve 71 is prevented in view of sealing engagement between the valve seat 93 and washer 78.

Anti-clockwise rotation of the wheel 86 will cause the pressure exerted on the piston 73 to be reduced and, the piston 73 will move in an axial direction towards the wheel 86 under the influence of second resilient means comprising the helical spring 87. A gap will appear between the valve seat 93 and washer 78 thus permitting fluid flow between inlet 90 and outlet 91.

The inlet 90 may be connected to a cold water supply or a hot water supply and water will flow through inlet 90 into the void 94 surrounding piston 73 through the gap between valve seat 93 and washer 78 and towards outlet 91. The outlet 91 is also connected to space 95 situated above or, as shown in Figure 3, to the right of diaphragm 76. If there is any change in pressure of the water supply through inlet 90 an increase in pressure will tend to move the piston down or in a direction away from the wheel 86 due to the increased pressure on diaphragm 76 which has the result of tending to close the valve, i.e. moving the washer 78 towards the valve seat 93. A decrease in pressure will have the opposite effect, i.e. the spring 87 will tend to increase the size of opening between the washer 78 and valve seat 93 since less force is exerted on the diaphragm 76 by the fluid.

The increasing or decreasing of the fluid flow path between valve seat 93 and washer 78 will tend to permit of increase in fluid flow when the pressure drops and decrease fluid flow when the pressure rises hence maintaining the fluid flow substantially constant.

The pressure regulating valve 72 operates in an identical manner and it will be appreciated that if, for example, the inlet 90 is connected to the cold water supply then the inlet 92 will be connected to the hot water supply and the outlet 91 will produce a mixture of hot and cold water which may be fed to a shower head, for example.

The valve is particular suitable for a shower installation since the user has independent control over both the hot and cold water supply and if, for example, the hot water supply was not particularly hot, then the cold water supply may be shut off completely thus relying on the hot water supply which, through the provision of a pressure regulating valve, will maintain a substantially constant flow n spite of fluctuation in water pressure.

Similarly, if it is merely desired to have a cold shower, the manually operable means or wheel controlling the supply of hot water may be maintained in its fully clockwise position thus preventing flow of hot water by ensuring that the valve seat, e.g. the valve seat 93 is in contact with sealing washer 78.

In the case where it is desired to have a supply of water, for example for a shower, which is a mixture of both hot and cold water to achieve the desired temperature both the manually operable means may be rotated to adjust the flow of both hot and cold supplies separately to achieve the desired temperature and in the event of fluctuations in the pressure of either or both of the hot and cold supplies the individual pressure regulating valves will alter the cross-section of the flow path through the gap between the valve seat 93 and washer 78 or the corresponding gap between the valve seat and washer in the valve 72 so as to maintain as near as possible the flow rate substantially constant. This prevents or minimises undesired sudden changes of temperature of the mixed water at outlet 91.

Various means for promoting or restricting flow through one of the valves may be provided. For example the various methods as described in relation to the first embodiment may be used.

The valve means is the subject of both embodiments of the present invention provides very satisfactory control means for mixing a hot and cold water supply has very considerable benefit in that a comparatively large amount of movement of the operating means causes a very small change to the mixture of the hot and cold water supplies. Conventional mixing valves operate in a manner so that a very small movement of the operating member causes a considerable change in the flow rates of the hot and cold supply.

The valve means of the present invention as envisaged in both the first and second embodiments provides a highly satisfactory control of a mixture of hot and cold water in installations such as showers, particularly where the installation is one where sudden changes in the pressure of the water supply, whether hot or cold, is expected to occur.In installations such as those found in, for example, mobile homes often the method of heating water is an instantaneous water heater and hence the heat input is substantially constant, fluctuations in water pressure however due to a plurality of users connected to the same supply can cause substantial and almost instantaneous changes in water pressure and it has been found that the valve means of the present invention provides a much quicker response to maintain a substantially constant pressure of mixed water than is the case with thermostatically controlled valves.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in the terms of means for performing the desired function, or a method or process for attaining the disclosed result, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (15)

1. Valve means for controlling a supply of water, comprising first and second pressure regulating valves each comprising an inlet and an outlet, a movable member having first resilient biasing means acting thereon, said movable member being adapted to be acted upon by fluid flowing from the inlet to the outlet in a manner to minimise fluctuations in fluid pressure at the outlet due to fluctuations in fluid pressure at the inlet and wherein said valves are provided with manually operable means, operable to move the position of said movable member through the intermediary of second resilient biasing means to different positions against the resilient bias provided by the first resilient biasing means, and hence to permit of an increase or decrease in the flow of fluid through said valve, and wherein said manually operable means is movable to a position in which the movable member is held in sealing engagement with a seat to prevent fluid flow from said inlet to said outlet, and wherein the inlet of said first valve is adapted for connection to a cold water supply and the inlet of said second valve is adapted for connection to a hot water supply and wherein the outlets of said first and second valves are connected together.

2. Valve means according to Claim 1 wherein the pressure regulating valves are provided with a single common manually operable means to move the position of the movable member of each valve.

3. Valve means according to Claim 1 wherein each pressure regulating valve is provided with a separate manually operable means to move the position of the movable member of each valve.

4. Valve means according to Claim 2 wherein one of the valves is caused to open before the other.

5. Valve means according to any of the preceding claims wherein the second resilient biasing means provided in the first pressure regulating valve is different from the second resilient biasing means in the second pressure regulating valve.

6. Valve means according to any one of Claims 1 to 4 wherein the valve means further comprises means acted on by the manually operable means to cause operation of the movable member of each valve such that one of the movable members is moved before there is any movement of the other movable member.

7. Valve means according to Claim 6 wherein the means for causing one movable member to move before there is any movement of the other movable member is an intermediary member movable by said manually operable means.

8. Valve means according to Claim 7 wherein the intermediary member is shaped or positioned so that it may cause movement of one movable member before there is any movement of the other movable member.

9. A method of maintaining a substantially constant temperature of water from a water supply wherein said water supply comprises a cold water supply and a hot water supply, the method comprising connecting inlets of first and second pressure regulating valves to said cold and hot water supplies respectively, wherein outlets of said first and second pressure regulating valves are connected to form a common outlet, in a manner such that fluctuations in fluid pressure at the common outlet due to fluctuations in fluid pressure at the inlet of either of said pressure regulating valves, are minimised by said pressure regulating valves.

10. Valve means substantially as hereinbefore described with reference to and as illustrated in Figures 1, 2, 3 of the accompanying drawings.

11. Valve means substantially as hereinbefore described with reference to and as illustrated in Figure 4 of the accompanying drawings.

12. A method of maintaining a substantially constant temperature of water from a water supply substantially as hereinbefore described with reference to and as illustrated in Figures 1, 2 and 3 of the accompanying drawings.

13. A method of maintaining a substantially constant temperature of water from a water supply substantially as hereinbefore described with reference to and as illustrated in Figure 4 of the accompanying drawings.

14. Valve means comprising any novel feature or novel combination of features described herein and/or in the accompanying drawings.

15. A method of maintaining a substantially constant temperature of water from a water supply comprising any novel feature or novel combination of features described herein and/or in the accompanying drawings.