GB2488755A

GB2488755A - A blender valve

Info

Publication number: GB2488755A
Application number: GB1103345.3A
Authority: GB
Inventors: Christopher John Samwell; John Michael Hall; Colin Arrowsmith
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-02-28
Filing date: 2011-02-28
Publication date: 2012-09-12
Anticipated expiration: 2031-02-28
Also published as: GB2488755B; GB201103345D0

Abstract

A fluid blender valve 2 comprising a first inlet 6 with a first inlet chamber 12, a second inlet 8 with a second inlet chamber 14, a blending chamber 36, a sleeve 18 movable in a linear direction along the valve housing 10 and defining an internal passage 34 for fluid flow from the first inlet chamber 12 to the blending chamber 36 wherein an outer surface of the sleeve 18 is in sliding contact with a seal part 16 of the valve housing 10, a first orifice defined between a first end of the sleeve 18 and a first valve seat 38 of the housing, and a second orifice defined between a second, opposite, end of the sleeve 18 and a second valve seat 44 of the valve housing wherein both orifices have variable cross sectional area. The first orifice is in fluid communication with the first inlet chamber 12 and the second orifice is in fluid communication with the second inlet chamber 14 such that the movement of the sleeve causes the cross sectional area of the orifices to alter so the fluid flow from the first and second inlet chambers is controlled. A dispensing device comprising the blender valve and a flow control valve is also disclosed.

Description

TITLE

Blender valves

DESCRIPTION

Technical Field

The present invention relates to blender valves, and in particular to valves that can be used to blend different fluids together in a desired ratio.

Summary of the Invention

The present invention provides a blender valve comprising: a valve housing; a first fluid inlet in fluid communication with a first inlet chamber and connectable to a first fluid source; a second fluid inlet in fluid communication with a second inlet chamber and connectable to a second fluid source; a blending chamber; a sleeve that is movable in a linear direction along an axis of the valve housing and which defines an internal passage through which fluid can flow from the first inlet chamber to the blending chamber, an outer surface of the sleeve being in sliding contact with a sea] part of the valve housing to provide a fluid-tight seal between the valve housing and the sleeve; wherein a first, preferably annular, orifice of variable cross sectional area is defined between a first end of the sleeve and a part of the valve housing or first valve seat, and a second, preferably annular, orifice of variable cross section is defined between a second, opposite, end of the sleeve and a part of the valve housing or second valve seat. During operation of the blender valve, the sleeve is preferably movable in a first linear direction where the cross sectional area of the first orifice is reduced and the cross sectional area of the second orifice is increased and is preferably movable in a second linear, opposite, direction where the cross sectional area of the first orifice is increased and the cross sectional area of the second orifice is reduced.

The axial position of the sleeve within the valve housing determines the cross sectional areas of the first and second orifices and hence the amount of fluid that can flow from each of the first and second fluid sources to the blending chamber. The first and second fluid inlets can be connected to the respective fluid sources by any suitable piping or conduit and may incorporate connectors and seals to allow the piping or conduit to be coimected to the inlets in a convenient manner.

When the cross sectional area of the first orifice is greater than zero (i.e. the first orifice is open) then fluid can flow through the first orifice from the first inlet chamber to the blending chamber through the internal passage in the sleeve. When the cross sectional area of the second orifice is greater than zero (i.e. the second orifice is open) then fluid can flow through the second orifice from the second inlet chamber to the blending chamber. if both the first and second orifices are at least partially open then the fluids supplied to the first and second fluid inlet chambers are blended or combined together in the blending chamber in a particular ratio to form a fluid mixture. The ratio is determined by the cross sectional areas of the first and second orifices and hence on the position of the sleeve within the valve housing. It will be readily appreciated that the term fluid mixture' is intended to also refer to a single fluid in the blending chamber in a situation where one of the first and second orifices is substantially closed as described below.

The sleeve is preferably linearly movable between a first limit where the cross sectional area of the first orifice is substantially zero (i.e. the first orifice is substantially closed) such that substantially no fluid can flow from the first inlet chamber to the blending chamber through the internal passage and the cross sectional area of the second orifice is substantially at a maximum, and a second limit where the cross sectional area of the first orifice is substantially at a maximum and the cross sectional area of the second orifice is substantially zero (i.e. the second orifice is substantially closed) such that substantially no fluid can flow from the second inlet chamber to the blending chamber.

Fluid pressure within the blender chamber preferably remains substantially constant during operation of the blender valve.

One of the first end of the sleeve and the first valve seat can have a tapered surface and the other of the first end of the sleeve and the first valve seat can have a substantially cylindrical surface with the first orifice being defined therebetween.

One of the second end of the sleeve and the second valve seat can have a tapered surface and the other of the second end of the sleeve and the second valve seat can have a substantially cylindrical surface with the second orifice being defined therebetween. In a preferred construction the first orifice is defined between a substantially cylindrical inner surface of the first end of the sleeve and a tapered (or frusto-conical) outer surface of the first valve seat which is received within the internal passage when the sleeve is at or near the first limit. Also, in the preferred construction the second orifice is defined between a substantially tapered (or frusto-conical) outer surface of the second end of the sleeve and a substantially cylindrical inner surface of the second valve seat which further defines part of the blender chamber and which substantially surrounds the second end of the sleeve when the sleeve is at or near the second limit. When the sleeve is at the first limit then fluid supplied to the first inlet chamber cannot flow into the internal passage through the first orifice because a substantially fluid-tight annular seal is formed between the cylindrical inner surface of the sleeve and the tapered outer surface of the first valve seat. However, fluid supplied to second inlet chamber can flow into the blending chamber through the second orifice which is at a maximum cross section. If the sleeve is moved linearly towards the second limit then fluid supplied to the first inlet chamber will begin to flow through the first orifice (i.e. between the cylindrical inner surface of the sleeve and the tapered outer surface of the first valve seat) through the internal passage and into the blending chamber where it is blended or combined together with fluid flowing from the second inlet chamber into the blending chamber through the second orifice. Tf the sleeve is located about halfway between the first and second limits then in the preferred construction fluid will be supplied to the blending chamber from the first and second inlet chambers in about equal amounts. If the sleeve is moved all the way to the second inlet then fluid supplied to the second inlet chamber cannot flow into the blending chamber because a substantially fluid-tight annular seal is formed between the tapered outer surface of the sleeve and the substantially cylindrical inner surface of the second valve seat. However, fluid supplied to the first inlet chamber can flow into the blending chamber through the first orifice which is at a maximum cross section and the internal passage in the sleeve. -4.-

The position of the sleeve within the valve housing will therefore determine the cross sectional areas of the first and second orifices and hence how much of each fluid is supplied to the blending chamber. In other words, fluids from the first and second fluid sources are supplied to the blending chamber at a particular ratio that is determined by the axial position of the sleeve within the valve housing. The blender valve can be used to control the composition of the fluid mixture within the blending chamber (i.e. the ratio of the fluids) or if the fluids are the same, but are supplied at different temperatures, then the blender valve can be used to control the temperature of the fluid mixture in the blending chamber.

Unlike for some known blender valves, there is no need for the pressures at which fluids are supplied to the first and second inlet chambers to be substantially the same, i.e. the blender valve of the present invention will work with relatively unbalanced fluid supply pressures. However, if the pressures at which fluids are supplied to the first and second inlet chambers are within a predetermined range of each other (e.g. 2 bar) then the fluid pressure within the blending chamber will preferably remain substantially constant as the sleeve moves linearly between the first and second limits.

This can be achieved by making the tapering surfaces of the sleeve and the valve seats substantially identical so that the cross sections of the first and second orifices vary in a substantially identical, but opposite, manner with the linear movement of the sleeve.

The tapering surfaces can be designed or selected to achieve the necessary degree of control over the cross sectional areas of the first and second orifices as a function of the linear movement of the sleeve and its axial position within the valve housing. For example, with very shallow tapering surfaces (i.e. small taper angles relative to a longitudinal axis of the valve housing) then the variation in the cross sectional areas of the first and second orifices will be very small as the sleeve moves within the valve housing and precise control of fluid flow through the blender valve can be achieved.

The tapering surfaces can have different taper angles if required for any purpose.

The seal part of the valve housing that is in sliding contact with the outer surface of the sleeve preferably separates the first and second inlet chambers.

The fluid mixture in the blending chamber preferably exits the blender valve through a fluid outlet.

The sleeve may be moved by any suitable actuator device such as a mechanical linear actuator, optionally operating under the control of an electronic controller. The electronic controller may move the sleeve automatically in response to a measured characteristic of the fluid mixture in the blending chamber such as its composition or temperature, for example. In other words, the electronic controller may use closed-loop control, optionally in real-time', where the sleeve is moved towards the first limit or the second limit by the actuator device in a controlled manner if the measured characteristic of the fluid mixture deviates from a preset or programmable (e.g. user-defined) setpoint against which the measured characteristic is compared. A measuring device such as a sensor may be located at, or adjacent to, the blending chamber and provide measurement data to the electronic controller, Additional or alternative measuring devices may also be provided remote from the blender valve.

For example, a temperature sensor may be provided at, or adjacent to, the point where the fluid mixture is dispensed or delivered so that the electronic controller may take into account any reduction in temperature as the fluid flows through any associated outlet piping or conduit.

The first and second fluid inlets are connectable to any suitable fluid sources, optionally being pressurised, pumped or gravity fed. Different fluids can be provided to the first and second fluid inlets. The fluids can be any suitable gases or liquids.

In one arrangement the fluids will be cold and hot water. The cold water may be from the pressurised mains supply and the hot water may be pumped or gravity fed from a hot water tank or cylinder, or supplied from a combi boiler, for example. The blender valve may be used to blend together cold and hot water in a particular ratio so that the water mixture in the blending chamber is at a desired or setpoint temperature. If the temperature of the cold or hot water changes for any reason while the fluid mixture is being dispensed or delivered by the blender valve then this will cause a deviation from the setpoint temperature that can be automatically compensated for by moving the position of the sleeve within the valve housing. The sleeve is also preferably moved automatically in response to any change in the setpoint temperature.

The blender valve may be used in any situation where the ratio of two fluids needs to be controlled and may be incorporated into a larger device or apparatus. It has possible applications in domestic, commercial, industrial and fluid-processing environments.

The blender valve may form part of a dispensing valve that also includes a flow control valve for controlling the flow rate of the fluid that is dispensed from a fluid outlet of the dispensing valve, optionally under the control of an electronic controller.

A fluid inlet of the flow control valve is preferably connected to the fluid outlet of the blender valve. A fluid outlet of the dispensing valve may be connected to any suitable dispensing unit. In an arrangement where the fluids are cold and hot water then the dispensing unit might be a shower unit, a tap or a domestic appliance such as a washing machine or dishwasher which require water to be supplied at a particular, typically user-defined, temperature and/or flow rate.

The actuator device of the blender valve and the flow control valve may be operated under the control of the same electronic controller. In such an arrangement the electronic controller may be programmed with a setpoint temperature and/or a setpoint flow rate. The blender valve will then blend together cold and hot water in a particular ratio so that the water mixture in the blending chamber is at the setpoint temperature and the flow control valve will ensure that the water mixture is supplied to the dispensing unit at the setpoint flow rate. The flow control valve may have any suitable construction but optionally includes a valve part having a tapered (or frusto-conical) outer surface that is movable in a linear direction along an axis of the flow control valve housing. An orifice, preferably annular, of variable cross sectional area is defined between the valve part and a part of the flow control valve housing or valve seat having a substantially cylindrical inner surface. The orifice separates an inlet chamber of the flow control valve, which is preferably connected to the blending chamber of the blender valve, from an outlet chamber of the flow control valve.

During operation of the flow control valve the valve part is linearly movable relative to the valve seat to change the cross sectional area of the orifice and hence the flow rate of fluid from the inlet chamber to the outlet chamber of the flow control valve.

The valve part may be moved by any suitable actuator device such as a mechanical linear actuator, optionally operating under the control of the electronic controller. The valve part is preferably movable between a first limit where the cross sectional area of the orifice is at a minimum and a second limit where the cross sectional area of the orifice is at a maximum. Even when the cross sectional area of the orifice is at a minimum it is generally preferred that fluid can flow from the inlet chamber to the outlet chamber of the flow control valve when the dispensing valve is operational. In other words, the flow control valve preferably does not function as a shut-off valve and merely controls the flow rate of the fluid through the dispensing valve beyond a minimum flow rate.

A temperature sensor may be located between the blender valve and the flow control valve (i.e. at, or adjacent to, the fluid outlet of the blender valve). The flow control valve, or more preferably a dedicated shut-off valve located downstream of the flow control valve, may be operated to stop the supply of fluid to the dispensing unit in the event that the measured temperature exceeds a preset threshold or limit to avoid scalding. If a shut-off valve is provided then it may also be operated under the control of the electronic controller. The shut-off valve is preferably used to control the on/off delivery of fluid from the dispensing valve so that the blender valve and the flow control valve remain pressurised even when fluid is not being dispensed or delivered.

The setpoint temperature and/or the setpoint flow rate are preferably user-defined and can be conveniently changed by means of an external device which provides control data to the electronic controller and is typically located at, or adjacent to, the dispensing unit. Many different types of user-defined control are possible. For example, the external device might be an electronic user interface, optionally incorporating a touch screen or user-operable buttons or dials, which allows the user to select any setpoint temperature and/or setpoint flow rate, typically within certain limits. In the case where the dispensing unit is a shower unit then the external device might have the appearance of a conventional bar' mixer shower fixture which typically has two rotating dials that allow independent control of temperature and flow rate. Instead of the rotating dials being used to mechanically operate a thermostatic valve and flow valve the external device may include electronic encoders which measure the position of the rotating dials and provide control data to the electronic controller. No water will flow through the external device which is simply provided with the appearance of a conventional bar' mixer shower because of its familiarity to the user -it is really only a convenient housing in which the electronic encoders and associated circuitry can be located. The fluid outlet of the dispensing valve is connected directly to the shower hose by suitable piping or conduit, the shower hose itself being connected to a conventional shower head or the like. It will therefore be readily appreciated that the external device for programming the setpoint temperature and/or setpoint flow rate could just as easily be an electronic user interface located within or near the shower enclosure, for example. The electronic controller can use the control data to detennine a setpoint temperature and setpoint flow rate based on the position of the rotating dials of the external device as measured by the electronic encoders. Similar electronic encoders can be placed within an external device having the appearance of a conventional single-lever mixer tap so that the electronic controller can use the control data to determine a setpoint temperature and flow rate based on the position of the lever. Any movement of the external device which selects a particular flow rate can also be used to turn on a shut-off valve so that fluid starts to be supplied to the shower hose or mixer tap. Other sorts of user-defined control might include touch control or voice-activated control, for example.

Because the operation of the dispensing valve is controlled by the electronic controller it allows alternative types of dispensing unit to be used, including those that that require no manual operation and might simply dispense or deliver water to a sink or bath through a basic opening or outlet.

The dispensing valve may be located remotely from the dispensing unit and may be connected to it by any suitable piping or conduit. For example, in the case of a shower unit or tap then the dispensing valve may be located in a convenient wall or ceiling space and connected to the shower hose or tap by means of conventional piping or conduit. My external device for adjusting the setpoint temperature and/or setpoint flow rate may also be located remote from the dispensing unit and any control data or measurement data that is exchanged between the electronic controller and component parts of the dispensing valve may be communicated by any suitable wired or wireless means. The electronic controller may form part of a home controller that is adapted to receive control data, including user-defined setpoints, over an Internet connection or by means of SMS messaging, for example.

The dispensing valve may further include a metering unit, optionally located between the flow control valve and any shut-off valve. The metering unit preferably determines the total volume of water that has flowed through the dispensing valve over a predetermined period. Preferably the total volume of water that has flowed through the dispensing valve since flow is started is determined in real time' by the metering unit and any associated processor unit, which in practice may be the electronic controller. This volume information is then provided to the user by means of a display which can provide a metered readout of the total volume of water that has been used in any suitable units, e.g. litres. The display can also provide time information about the length of time the dispensing valve has been operating, i.e. the time elapsed. If the metering unit is a flow rate meter then the display can provide flow rate information about the current volumetric flow rate in any suitable units, e.g. litres/second. The user can see how much fluid has been used and can use this information to try and reduce their consumption for environmental reasons or to simply reduce metered charges, for example. The display can be provided at any suitable location, but preferably at, or adjacent to, the dispensing unit. The metering unit is particularly suitable for shower units since it allows the user to see how much water they have consumed and for how long the shower has been running. In a preferred arrangement the display will provide both volume and time information to the user. Additional information such as the temperature of the fluid flowing through the dispensing valve or warnings may also be displayed on the display. For example, if the total volume of fluid measured by the metering means exceeds a certain threshold then this can be communicated to the user through the display. The threshold may optionally be set by the user and may, for example, represent the maximum volume of water that they believe should be used when taking a shower. A similar threshold can be applied to the time elapsed. Time, volume and temperature measurements might also be combined to provide information about energy consumption.

The display can be configured to show some or all of the available information at any given time. The information that is displayed can be cycled.

The metering unit can incorporate a flow rate meter or a volume meter of any suitable type.

The dispensing valve may be used to provide fluid to a plurality of dispensing units.

More particularly, an outlet of the flow control valve may be connected in parallel to a plurality of dispensing units, optionally by dedicated shut-off valves so that fluid flow to each dispensing unit can be selectively and independently controlled. For example, a single dispensing valve for a bathroom may be used to supply water to a shower unit, a bath tap and a sink tap by the selective operation of the appropriate shut-off valve. Temperature and flow rate balancing may be required if water needs to be supplied to more than one dispensing unit at the same time and each requires a different setpoint temperature andlor setpoint flow rate.

Drawings Figure 1 is a cross section view through a dispensing valve according to the present invention with the blender valve and flow control valve in a first position; Figure 2 is a detail view of the blender valve of Figure 1; Figure 3 is a cross section view through the dispensing valve of Figure 1 with the blender valve and flow control valve in a second position; Figure 4 is a detail view of the blender valve of Figure 3; Figure 5 is a cross section view along the line A-A of Figure 1; and Figure 6 is a cross section view along the line B-B of Figure 1.

With reference to Figures 1 to 6 a dispensing valve 2 includes a blender valve 4, a flow control valve 100, a metering and display unit 200, and a solenoid shut-off valve 300.

The blender valve 4 includes a cold water inlet 6 that is connected to the pressurised mains water supply and a hot water inlet 8 that is connected to a hot water cylinder (not shown) by means of a pump (not shown) that operates automatically whenever hot water is demanded. A valve housing 10 defines a cold water inlet chamber 12 and a hot water inlet chamber 14 that are separated by a radially-inwardly extending annular seal part 16 which is in sliding contact with the outer surface of a tubular shroud or sleeve 18 to define a water-tight seal between the valve housing 10 and the sleeve.

The sleeve 18 is mounted on the moving arm of a linear actuator 20 and can move in a linear direction along a longitudinal axis of the valve housing. With particular reference to Figures 2 and 4, the sleeve 18 has a first end 22 which has a cylindrical outer surface 24 and a cylindrical inner surface 26, and a second end 28 which has a tapered outer surface 30 and a cylindrical inner surface 32. The cylindrical outer surface 24 remains in sliding contact with the annular seal part 16 at all times. The inner surfaces 26, 32 of the sleeve 18 define an internal conduit or passage 34 through which cold water can flow from the cold water inlet chamber 12 to a blending chamber 36. The linear actuator 20 is controlled by an electronic controller EC to selectively move the sleeve 18 in the linear direction to a position that lies between a first limit shown in Figures 1 and 2 and a second limit shown in Figures 3 and 4.

When the sleeve 18 is at the first limit shown in Figures 1 and 2 then the cylindrical inner surface 26 of the first end of the sleeve is in contact with a first valve seat 38 that has a tapered outer surface 40. The contact between the sleeve 18 and the first valve seat 38 forms a water-tight seal and cold water cannot flow from the cold water inlet chamber 12 to the blending chamber 36 through the internal passage 34. An annular orifice 42 is defined between the tapered outer surface 30 of the second end of the sleeve 18 and a second valve seat 44. When the sleeve 18 is at the first limit then -12-the annular orifice 42 is at its maximum cross section and hot water can flow from the hot water inlet chamber 14 to the blending chamber 36 through the annular orifice 42.

When the sleeve is at the second limit shown in Figures 3 and 4 then an annular orifice 46 is defined between the cylindrical inner surface 26 of the first end of the sleeve 18 arid the first valve seat 38. The annular orifice 46 is at its maximum cross section and cold water can flow from the cold water inlet chamber 12 to the blending chamber 36 though the internal passage 34. The tapered outer surface 30 of the second end of the sleeve 18 is in contact with the cylindrical inner surface 48 of the second valve seat 44. The contact between the sleeve 18 and the second valve seat 44 forms a water-tight seal and hot water cannot flow from the hot water inlet chamber 14 to the blending chamber 36.

If the sleeve 18 is at a position between the first and second limits then cold and hot water can flow from their respective inlet chambers 12, 14 to the blending chamber 36 at a particular ratio, that ratio being determined by the position of the sleeve within the valve housing 10 and in particular by the size of the cross sectional areas of the annular orifices 42, 46. The cold and hot water is blended or combined together in the blending chamber 36 to provide water having a desired or setpoint temperature. If the water in the blending chamber 36 is too hot then the sleeve 18 is moved by the linear actuator 20 under the control of the electronic controller EC towards the second limit so that the cross sectional area of the annular orifice 46 is increased to allow more cold water to flow into the blending chamber 36 and the cross sectional area of the annular orifice 42 is reduced to allow less hot water to flow into the blending chamber or vice versa. The outer surface 40 of the first valve seat 38 and the outer surface 30 of the second end of the sleeve 18 have the same taper angle so that the cross sectional area of each annular orifice 42, 46 varies in substantially the same manner as the sleeve is moved within the valve housing 10. In other words, if the cross sectional area of the annular orifice 42 is increased by a particular amount then the cross sectional area of the annular orifice 46 is preferably reduced by substantially the same amount. This preferably ensures that the pressure within the blending chamber 36 remains substantially constant at all times as long as the pressures at which the cold -13 -and hot water are supplied to the inlets 12, 14 do not vary and are within a particular acceptable range of each other. Precisely balanced pressures for the cold and hot water supplies are not necessary.

A temperature sensor 50 is provided at an outlet of the blender valve 4 and measures the temperature of the water as it leaves the blending chamber 36. Measurement data (Tm) is provided to the electronic controller EC.

The outlet of the blender valve 4 is connected directly to an inlet chamber 102 of the flow control valve 100. The flow control valve 100 includes a valve part 104 mounted on the moving arm of a linear actuator 106 and which can move in a linear direction along a longitudinal axis of the valve housing 108. The valve part 104 has a tapered outer surface 110 and moves relative to a valve seat 112 which has a cylindrical inner surface 114. An annular orifice 116 is defined between the tapered outer surface 110 of the valve part 104 and the cylindrical inner surface 114 of the valve seat 112 and it separates the inlet chamber 102 of the flow control valve from an outlet chamber 118. The linear actuator 106 is controlled by the electronic controller EC to selectively move the valve part 104 in the linear direction to a position that lies between a first limit shown in Figure 1 and a second limit shown in Figure 3.

When the valve part 104 is at the first limit shown in Figure 1 then the annular orifice 116 between the tapered outer surface 110 of the valve part 104 and the cylindrical inner surface 114 of the valve seat 112 is at a maximum and the flow rate at which water can flow from the inlet chamber 102 to the outlet chamber 118 of the flow control valve is also at a maximum. When the valve part is at the second limit shown in Figure 3 then the annular orifice 116 between the tapered outer surface 110 of the valve part 104 and the cylindrical inner surface 114 of the valve seat 112 is at a minimum and the flow rate at which water can flow from the inlet chamber 102 to the outlet chamber 118 of the flow control valve is also at a minimum.

The electronic controller EC provides control data to the linear actuators 20, 106 to control the position of the sleeve 18 and the valve part 104 within their respective valve housings. The measurement data (Tm) provided by the temperature sensor 50 is compared against a user-defined setpoint temperature (Ts) and if there is any deviation between the measured temperature and the setpoint temperature then the electronic controller EC provides control data to the linear actuator 20 of the blender valve 4 to automatically adjust the axial position of the sleeve 18 until the correct temperature is achieved. For example, if the measured temperature is above the setpoint temperature (Ts) then the sleeve 18 is moved towards the second limit so that more cold water is allowed to flow to the blending chamber 36 through the annular orifice 46 and less hot water is allowed to flow to the blending chamber through the annular orifice 42 or vice versa. It will be readily appreciated that the sleeve 18 may be made to move if the setpoint temperature (Ts) is changed or if the temperature of the cold or hot water that is supplied to the inlets 12, 14 changes while the dispensing valve is in operation.

A user-defined setpoint flow rate (Fs) is also used to determine the position of the valve part 104 of the flow control valve 100. The valve part 104 of the flow control valve 100 may be made to move if the setpoint flow rate is changed. Often it will not be necessary for position of the valve part 104 to be automatically adjusted in response to a measured flow rate, i.e. by closed-loop control.

A conventional shut-off valve 300 may be operated under the control of the electronic controller EC. It will be readily appreciated that water will only be supplied through an outlet 302 of the dispensing valve when the shut-off valve 300 is open. The flow rate at which water is supplied is determined by the flow control valve 100. The blender valve 4 and flow control valve 100 remain pressurised when the shut-off valve 300 is closed. The shut-off valve 300 is closed automatically if the measured temperature of the water leaving the blending chamber 36 exceeds a preset threshold to avoid scalding, for example. The same threshold may define an upper limit for the user-defined setpoint temperature.

A metering and display unit 200 is located between the outlet chamber 118 of the flow control valve 100 and the shut-off valve 300. As the water flows through a -15 -shaped chamber 202 formed in the main body of the metering and display unit then it causes a paddle wheel 204 to rotate. The number of rotations of the paddle wheel 204 can be measured using an optical reader 206 that is aligned with a shutter or notch in the paddle wheel every time it completes one revolution. A display 208 is located within the metering and display unit 200 but it could be located remotely. The metering and display unit 200 remains in a standby mode until water starts to flow through the dispensing valve 2. The metering and display unit 200 can be turned on in response to the rotation of the paddle wheel 204 and a timer is started. The metering and display unit 200 measures the total amount of water that has flowed through the dispensing valve 2 by measuring the number of rotations of the paddle wheel 204 using the optical reader 206, Time information and volume information is displayed on the display 208. More particularly, the display 208 can show the amount of time that has elapsed since the metering and display unit 200 was turned on and the total amount of water that has flowed through the dispensing valve 2 since the metering and display unit was turned on. Additional information such as the measured temperature of the water leaving the blender valve 4 or the flow rate can also be displayed.

The metering and display unit 200 can be powered by a battery or from electrical energy generated by the rotation of the paddle wheel 204.

The blender valve 4, flow control valve 100, metering and display unit 200 and shut-off valve 300 may be formed as separate components and then connected together to form the complete dispensing valve 2.

Claims

-16 -CLAIMS1. A blender valve comprising: a valve housing; a first fluid inlet in fluid communication with a first inlet chamber and connectable to a first fluid source; a second fluid inlet in fluid communication with a second inlet chamber and connectable to a second fluid source; a blending chamber; a sleeve that is movable in a linear direction along an axis of the valve housing and which defines an internal passage through which fluid can flow from the first inlet chamber to the blending chamber, an outer surface of the sleeve being in sliding contact with a seal part of the valve housing to provide a fluid-tight seal between the valve housing and the sleeve; wherein a first orifice of variable cross sectional area is defined between a first end of the sleeve and a part of the valve housing or first valve seat, and a second orifice of variable cross section is defined between a second, opposite, end of the sleeve and a part of the valve housing or second valve seat.
2. A blender valve according to claim 1, wherein the sleeve is movable in a first linear direction where the cross sectional area of the first orifice is reduced and the cross sectional area of the second orifice is increased and is movable in a second linear, opposite, direction where the cross sectional area of the first orifice is increased and the cross sectional area of the second orifice is reduced.
3. A blender valve according to claim 1 or claim 2, wherein the axial position of the sleeve within the valve housing determines the cross sectional areas of the first and second orifices and hence the amount of fluid that can flow from each of the first and second fluid sources to the blending chamber.
4. A blender valve according to any preceding claim, wherein the sleeve is linearly movable between a first limit where the cross sectional area of the first orifice is substantially zero such that substantially no fluid can flow from the first inlet chamber to the blending chamber through the internal passage and the cross sectional area of the second orifice is substantially at a maximum, and a second limit where the cross sectional area of the first orifice is substantially at a maximum and the cross sectional area of the second orifice is substantially zero such that substantially no fluid can flow from the second inlet chamber to the blending chamber.
5. A blender valve according to any preceding claim, wherein fluid pressure within the blender chamber preferably remains substantially constant in use.
6. A blender valve according to any preceding claim, wherein one of the first end of the sleeve and the first valve seat has a tapered surface and the other of the first end of the sleeve and the first valve seat has a substantially cylindrical surface with the first orifice being defined therebetween.
7. A blender valve according to any preceding claim, wherein one of the second end of the sleeve and the second valve seat has a tapered surface and the other of the second end of the sleeve and the second valve seat has a substantially cylindrical surface with the second orifice being defined therebetween.
8. A blender valve according to claim 4, wherein the first orifice is defined between a substantially cylindrical inner surface of the first end of the sleeve and a tapered outer surface of the first valve seat which is received within the internal passage when the sleeve is at or near the first limit.
9. A blender valve according to claim 8, wherein the second orifice is defined between a substantially tapered outer surface of the second end of the sleeve and a substantially cylindrical inner surface of the second valve seat which further defines part of the blender chamber and which substantially surrounds the second end of the sleeve when the sleeve is at or near the second limit. -18-
10. A blender valve according to claim 9, wherein the tapered outer surfaces are substantially identical so that the cross sections of the first and second orifices vary in a substantially identical, but opposite, manner with the linear movement of the sleeve.
11. A blender valve according to any preceding claim, wherein the seal pan of the valve housing that is in sliding contact with the outer surface of the sleeve separates the first and second inlet chambers.
12. A blender valve according to any preceding claim, wherein the fluid mixture in the blending chamber exits the blender valve through a fluid outlet.
13. A blender valve according to any preceding claim, wherein the sleeve is moved by an actuator device.
14. A blender valve according to claim 13, wherein the actuator device is operated under the control of an electronic controller.
15. A blender valve according to claim 14, wherein the electronic controller moves the sleeve automatically in response to a measured characteristic of the fluid mixture in the blending chamber.
16. A blender valve according to claim 15, wherein the electronic controller uses closed-loop control where the sleeve is moved towards the first limit or the second limit by the actuator device in a controlled maimer if the measured characteristic of the fluid mixture deviates from a preset or programmable setpoint against which the measured characteristic is compared.
17. A blender valve according to claim 16, wherein the measured characteristic is temperature and the preset or programmable setpoint is a temperature setpoint.
-19 - 118. A blender valve according to any of claims 14 to 17, further comprising a measuring device located at or adjacent the blending chamber and providing measurement data to the electronic controller.
19. A blender valve according to any of claims 14 to 18, further comprising a measuring device remote from the blender valve.
20. A dispensing valve comprising: a blender valve according to any preceding claim; and a flow control valve for controlling the flow rate of the fluid that is dispensed from a fluid outlet of the dispensing valve.
21. A dispensing valve according to claim 20, wherein the flow control valve is operated under the control of an electronic controller.
22. A dispensing valve according to claim 20 or claim 21, wherein a fluid inlet of the flow control valve is connected to the fluid outlet of the blender valve.
23. A dispensing valve according to any of claims 20 to 22, wherein a fluid outlet of the dispensing valve is connected to a dispensing unit.
24. A dispensing valve according to any of claims 20 to 23, wherein the flow control valve includes a valve part having a tapered outer surface that is movable in a linear direction along an axis of the flow control valve housing, and an orifice of variable cross sectional area is defined between the valve part and a part of the flow control valve housing or valve seat having a substantially cylindrical inner surface.
25. A dispensing valve according to claim 24, wherein the orifice separates an inlet chamber of the flow control valve from an outlet chamber of the flow control valve.

-20 -
26. A dispensing valve according to claim 24 or claim 25, wherein the valve part is movable between a first limit where the cross sectional area of the orifice is at a minimum and a second limit where the cross sectional area of the orifice is at a maximum.
27. A dispensing valve according to any of claims 20 to 26, further comprising a temperature sensor located between the blender valve and the flow control valve.
28. A dispensing valve according to any of claims 20 to 27, further comprising a shut-off valve to control the onloff delivery of fluid from the dispensing valve.
29. A dispensing valve according to any of claims 20 to 28, further comprising a metering unit.
30. A dispensing valve according to claim 28, further comprising a metering unit located between the flow control valve and the shut-off valve.
31. A dispensing valve according to any of claims 20 to 30, wherein an outlet of the flow control valve is connected in parallel to a plurality of dispensing units.
32. A blender valve substantially as described herein and with reference to the drawings.AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS: 1. A blender valve comprising: a valve housing; a first fluid inlet in fluid communication with a first inlet chamber and connectable to a first fluid source; a second fluid inlet in fluid communication with a second inlet chamber and connectable to a second fluid source; a blending chamber; a sleeve that is movable in a linear direction along an axis of the valve housing and which defines an internal passage through which fluid can flow from the first inlet chamber to the blending chamber, an outer surface of the sleeve being in sliding contact with a seal part of the valve housing to provide a fluid-tight seal between the valve housing and the sleeve; wherein a first orifice of variable cross sectional area is defined between a first end of the sleeve and a first valve seat of the valve housing, and a second orifice of variable cross sectional area is defined between a second, opposite, end of the sleeve * . and a second valve seat of the valve housing; * :* : :* wherein the first orifice is in fluid communication with the first inlet chamber and the internal passage; wherein the second orifice is in fluid communication with the second inlet C::> chamber and the blending chamber; *> wherein one of the first end of the sleeve and the first valve seat has a tapered surface and the other of the first end of the sleeve and the first valve seat has a substantially cylindrical surface with the first orifice being defined therebetween; wherein one of the second end of the sleeve and the second valve seat has a tapered surface and the other of the second end of the sleeve and the second valve seat has a substantially cylindrical surface with the second orifice being defined therebetween; and wherein the sleeve is movable in a first linear direction where the cross sectional area of the first orifice is reduced and the cross sectional area of the second orifice is increased and is movable in a second linear, opposite, direction where the a cross sectional area of the first orifice is increased and the cross sectional area of the second orifice is reduced.2. A blender valve according to claim 1, wherein the axial position of the sleeve within the valve housing determines the cross sectional areas of the first and second orifices and hence the amount of fluid that can flow from each of the first and second fluid sources to the blending chamber.3. A blender valve according to claim 1 or claim 2, wherein the sleeve is linearly movable between a first limit where the cross sectional area of the first orifice is substantially zero such that substantially no fluid can flow from the first inlet chamber to the blending chamber through the internal passage and the cross sectional area of the second orifice is substantially at a maximum, and a second limit where the cross sectional area of the first orifice is substantially at a maximum and the cross sectional area of the second orifice is substantially zero such that substantially no fluid can flow * : from the second inlet chamber to the blending chamber.S..... * .*::: 4. A blender valve according to any preceding claim, wherein fluid pressure within the blender chamber preferably remains substantially constant in use.*> 5. A blender valve according to claim 3, wherein the first orifice is defined * * between a substantially cylindrical inner surface of the first end of the sleeve and a tapered outer surface of the first valve seat which is received within the internal passage when the sleeve is at or near the first limit.6. A blender valve according to claim 5, wherein the second orifice is defined between a substantially tapered outer surface of the second end of the sleeve and a substantially cylindrical inner surface of the second valve seat which further defines part of the blender chamber and which substantially surrounds the second end of the sleeve when the sleeve is at or near the second limit.7. A blender valve according to claim 6, wherein the tapered outer surfaces are substantially identical so that the cross sections of the first and second orifices vary in a substantially identical, but opposite, manner with the linear movement of the sleeve.8. A blender valve according to any preceding claim, wherein the seal part of the valve housing that is in sliding contact with the outer surface of the sleeve separates the first and second inlet chambers.9. A blender valve according to any preceding claim, wherein the fluid mixture in the blending chamber exits the blender valve through a fluid outlet.10. A blender valve according to any preceding claim, wherein the sleeve is moved by an actuator device.11. A blender valve according to claim 10, wherein the actuator device is operated under the control of an electronic controller.U S.... * .12. A blender valve according to claim 11, wherein the electronic controller moves the sleeve automatically in response to a measured characteristic of the fluid mixture in the blending chamber. * . * SI*13. A blender valve according to claim 12, wherein the electronic controller uses closed-loop control where the sleeve is moved towards the first limit or the second limit by the actuator device in a controlled manner if the measured characteristic of the fluid mixture deviates from a preset or programmable setpoint against which the measured characteristic is compared.14. A blender valve according to claim 13, wherein the measured characteristic is temperature and the preset or programmable setpoint is a temperature setpoint.15. A blender valve according to any of claims 11 to 14, further comprising a measuring device located at or adjacent the blending chamber and providing measurement data to the electronic controller.16. A blender valve according to any of claims 11 to 15, further comprising a measuring device remote from the blender valve.17. A dispensing valve comprising: a blender valve according to any preceding claim; and a flow control valve for controlling the flow rate of the fluid that is dispensed from a fluid outlet of the dispensing valve.18. A dispensing valve according to claim 17, wherein the flow control valve is operated under the control of an electronic controller.19. A dispensing valve according to claim 17 or claim 18, wherein the fluid *:" ; mixture in the blending chamber exits the blender valve through a fluid outlet and a * : : fluid inlet of the flow control valve is connected to the fluid outlet of the blender valve.20. A dispensing valve according to any of claims 17 to 19, wherein a fluid outlet of the dispensing valve is connected to a dispensing unit.21. A dispensing valve according to any of claims 17 to 20, wherein the flow control valve includes a valve part having a tapered outer surface that is movable in a linear direction along an axis of the flow control valve housing, and an orifice of variable cross sectional area is defined between the valve part and a valve seat of the control valve housing having a substantially cylindrical inner surface.22. A dispensing valve according to claim 21, wherein the orifice separates an inlet chamber of the flow control valve from an outlet chamber of the flow control valve.23. A dispensing valve according to claim 21 or claim 22, wherein the valve part is movable between a first limit where the cross sectional area of the orifice is at a minimum and a second limit where the cross sectional area of the orifice is at a maximum.24. A dispensing valve according to any of claims 17 to 23, further comprising a temperature sensor located between the blender valve and the flow control valve.25. A dispensing valve according to any of claims 17 to 24, further comprising a shut-off valve to control the on!off delivery of fluid from the dispensing valve.26. A dispensing valve according to any of claims 17 to 25, further comprising a metering unit.27. A dispensing valve according to claim 25, further comprising a metering unit located between the flow control valve and the shut-off valve. * 0. S. S * *028. A dispensing valve according to any of claims 17 to 27, wherein an outlet of the flow control valve is connected in parallel to a plurality of dispensing units. S... S *29. A blender valve substantially as described herein and with reference to the drawings.