GB2429760A

GB2429760A - Mixer tap and valve

Info

Publication number: GB2429760A
Application number: GB0615548A
Authority: GB
Inventors: William Peter Herring; James Moore
Original assignee: Hornbeam Ivy Ltd
Current assignee: Hornbeam Ivy Ltd
Priority date: 2005-08-08
Filing date: 2006-08-04
Publication date: 2007-03-07
Anticipated expiration: 2026-08-04
Also published as: GB2429760B; GB0615548D0

Abstract

A mixer tap assembly 10 has a mixing chamber 12 for mixing fluids from two inputs 14, 16 and a mix controller to control the ratio of fluid flow into the mixing chamber 12 from the inputs. The mix controller includes a mix actuator 30 which operates mix control means, such as a rotatable sleeve (36, Fig.3) which is connected to valve means associated with the mixing chamber 12. The mix actuator 30 and a fluid outlet 34 are mountable on or above a work surface via mounting means 26, 27 while the mixing chamber 12 is mountable below the work surface. The mix control means (36, Fig. 3) and an output conduit 18 between the fluid outlet 34 and the mixing chamber 12, pass through a bore in the mounting means 26, 27 thus minimising the footprint of the mixer tap assembly on the work surface.

Description

MIXER TAP AND MIXER VALVE

The present invention relates to mixer taps, i.e. taps with a plurality of fluid inputs which are mixable to be ejected from one or more common outputs. For example, mixer taps are used on kitchen sinks to provide a single water supply with controllable temperature. The present invention is applicable to mixer taps having a pull-out or pull-down spray facility, i.e. where the or an additional fluid outlet is detachable from the main unit to give flexible user-directable flow.

The present invention also relates to mixer valves, i.e. units which receive two or more fluid inputs (e.g. hot and cold water) and are arranged controllably to produce a mixed fluid output. Mixer valves are typically used in taps (faucets), showers and the like.

Mixer taps are well known. Typically, fluid input from a plurality of sources (usually hot and cold water supplies) is controllably conveyed to a mixing chamber, where the fluid is mixed and ejected through an output spout. Such mixer taps commonly use a single lever mixing valve to control the flow rate and temperature of the ejected water. Temperature is controlled by adjusting the ratio of hot to cold inputs received in the mixing chamber. A single lever mixing valve can control these two properties using a combination of rotational and tilting movements of an actuator operably connected to the control lever of the mixing valve. For example, the actuator (e.g. tap head) may be rotated to control temperature and tilted to control flow rate. This is conventional.

To give greater flexibility it is increasingly common to combine a side spray unit with the main mixer tap. Previously, separate side sprays were used, but when used with mixer taps these suffered from problems in efficiently delivering mixed water from the mixing chamber to the side spray. For example, one proposal incorporated an automatic diverter valve in the mixer tap to deflect water to a side spray when the side spray was operated. To fit in the mixer tap, the diverter valve was small, which meant that in time it was liable to become clogged with limescale and therefore reduce flow to the spray. By combining the side spray unit with the main tap, the problems caused by the diverter valve could be avoided.

In one combined proposal (known as a pull-out spray), a spray head is removably attached to the side of the tap beneath the mixing valve with a hose connecting the spray head to the valve. In another combined proposal (known as a pull-down spray), the main tap spout has a traditional goose neck configuration through which the tube that feeds the spray nozzle passes. The spray nozzle is removably attached to the mouth of the spout; when attached it operates as the main tap outlet, when detached (pulled down) it operates as a hand spray.

Typically the connecting hose is longer than the spout to give flexibility of movement.

Combined arrangements of the sort described above often require large housings to contain the components.

For example, it can be necessary for the tap housing to contain the valve apparatus and mixing chamber. Such large housings can be undesirable as they take up space and may not be aesthetically pleasing. Usually, the excess hose is looped under the work surface to stay out of sight. Thus, space must be made for the connecting hose to pass through the work surface twice, as well as to allow for the input supplies to the mixing chamber.

This may give the tap assembly a large footprint on the Conventional mixer valves typically have a housing which receives two fluid inputs and provides them to a mixing unit which comprises two ceramic discs, which are movable relative to one another. In one arrangement, one of the ceramic discs is fixed in the housing with the other being movable by an external controller. The fixed disc has two holes therethrough which receive fluid from the respective inputs. The fixed disc has another hole in fluid communication with an outlet to permit fluid to leave the housing. The movable plate includes a mixing chamber (e.g. a recess) which can selectively join either or both input holes to the output hole so that fluid can flow from the inputs to the outlet, mixing in the mixing chamber as it does so.

The above type of arrangement is used in a single lever mixing cartridge, which provides separate control of the mixing proportion and flow rate through the provision of a single control lever that is movable in two distinct ways. Typically, the lever is tiltable to control flow rate, e.g. by moving the mixing chamber into or out of fluid communication with the input holes, and rotatable to control mixing proportion (e.g. temperature) . However, such complex movement is not always easily or conveniently controllable, e.g. in small spaces or where the mixer valve needs to be at a distance from an operating device.

US 2005/0076960 proposes a mixer valve where the hot and cold inputs are connected to respective valve cartridges, which are independently operated by separate tap controllers. The valve cartridges used are standard: fluid is received into the base, and flows out of an outlet in the cartridge side wall under the control of a valve, which is operated by a rotatable control spindle which protrudes from the top of the cartridge. There is a geared connection between the tap controllers (e.g. handle) and the control spindles of the valve cartridges.

The gearing ratio is arranged to make the operation angle of the tap controllers larger than the operation angle of its respective cartridge control spindle. This can give greater mechanical advantage and facilitate temperature control. However, the flow rate out of the mixer valve is not easily controlled without. affecting the mixing proportion (temperature) of the output fluid.

The present invention aims to address the problems mentioned above. The present invention also aims to provide an improved mixer valve where mixing proportion and output flow rate are independently controllable in a simple fashion. Combinations of different types of motion (e.g. the tilting and rotating of known devices) is preferably avoided; for example, the mixing proportion and output flow rate may be controllable using only rotational motion.

At its most general, the invention provides a mixer tap assembly with a control mechanism for controlling input to and output from a mixing chamber where the control mechanism includes means for communicating through a work surface via the same path as an output fluid flow to allow components of the assembly such as the mixing chamber to be located below the work surface.

Accordingly, the size of that part of the assembly to be mounted on or above the work surface, e.g. in view of the user during normal use, can be kept small and/or made more aesthetically pleasing.

There are many ways of controlling the output from the mixing chamber. One way is to indirectly control the output by controlling the input into the mixing chamber.

Another way is to have separate control means for controlling the output independently of control of the input.

The present invention also provides a mixer valve having three valve portions associated with fluid inputs and outputs so that fluid flow out of the mixer valve is controllable separately from (i.e. independently of) the proportion of fluid received from each input.

It is to be noted that the terms "above" and "below" as used hereafter refer to positions of elements relative to each other, and of course do not limit the components of the invention to a particular orientation relative to the earth.

Thus, in one aspect the present invention may provide a mixer tap assembly having: a mixing chamber mountable below a work surface for mixing fluid receivable from two inputs which are in fluid communication with the mixing chamber; a fluid outlet mountable on or above the work surface; an output conduit in fluid communication with the mixing chamber to carry mixed fluid to the fluid outlet; a flow controller operable to control fluid flow out of the mixing chamber into the output conduit; and a mix controller operable to control fluid input received in the mixing chamber; wherein: the flow controller has a flow actuator that is mountable on or above the work surface and arranged to operate flow control means which are communicable with the mixing chamber through the work surface to control fluid flow out of the mixing chamber; the mix controller has a mix actuator that is mountable on or above the work surface and arranged to operate mix control means which are communicable with the mixing chamber through the work surface to perform the fluid input control; and the flow control means, mix control means and output conduit share a common path through the work surface.

The mounting of components of the assembly above and below the work surface is normally achieved by using mounting means for attaching the assembly to the work surface. The mounting means may be a housing and backing nut on opposite sides of the work surface. The components of the assembly are positioned relatively above or below the mounting means of the assembly and are thus located above or below the work surface when the mounting means is attached to it.

The listed components of the assembly which are adapted to share a common path through the work surface normally do so by passing through a bore in the mounting means. Therefore, the present invention may also provide a mixer tap assembly having: mounting means for attaching the assembly to a work surface; a mixing chamber positioned below the mounting means for mixing fluid receivable from two inputs which are in fluid communication with the mixing chamber; a fluid outlet positioned above the mounting means, which fluid outlet is located at the end of a spout; an output conduit in fluid communication with the mixing chamber for carrying mixed fluid to the fluid outlet; and a mix controller including mix valve means associated with the mixing chamber, the mix controller being operable to control the ratio of fluid received in the mixing chamber from the two inputs; wherein the mix controller further includes a mix actuator positioned above the mounting means and arranged to operate mix control means which is communicable with the mix valve means to perform the fluid input control; and wherein the mix control means and the output conduit pass through a bore in the mounting means.

Thus, the mixer tap assembly may be arranged to be mounted in a sink unit, e.g. a kitchen sink, with the mixing chamber under the sink surface, i.e. out of sight during normal use, so that preferably only the fluid outlet, flow actuator and mix actuator are on view.

The output conduit typically travels through a hole formed through the work surface (sink surface) . The fluid outlet is preferably mountable over this hole to receive the output conduit.

Preferably, the assembly includes a housing mountable on the work surface. The housing preferably has any one or more or all of the flow actuator, mix actuator and fluid outlet mounted thereon.

Preferably, the fluid outlet is connected to the output conduit. For example, the fluid outlet may be a nozzle, e.g. a spray head nozzle mountable on the housing. The spray head nozzle may be detachable from the housing, e.g. to form a pull-out spray.

Preferably, the tap assembly includes a spout extending from the housing. In one arrangement, the spout may be provided with its own water supply from the mixing chamber. Alternatively, the fluid outlet may be located at, e.g. detachably mountable on, the end of the spout. The spout may form a passageway for the output conduit, so that the fluid outlet (spray head nozzle) is detachable from the end of the spout to form a pull-down spray. In a preferred embodiment, the spout has a goose- neck configuration.

Thus, the present invention is equally applicable to mixer tap assemblies where the spray unit doubles as the main fluid supply (pull-down sprays) and mixer tap assemblies having an independent spray unit and main fluid supply on a common housing.

Preferably, the flow and/or mix control means include a physical connection to the mixing chamber, e.g. directly to control valve or valves at the inputs and/or output of the mixing chamber. In this case, the output conduit and control means may pass through a common hole, e.g. a single hole, in the work surface. The output conduit therefore only passes through the work surface once, thereby reducing the footprint of the tap assembly compared with known devices. The footprint is further reduced by locating the mixing chamber (and hence its inputs) below the work surface.

Preferably, the flow controller is arranged to control fluid flow rate through the output conduit. In other words, it controls the volume of fluid delivered by the tap assembly per unit time. The mixing chamber may include an output valve operable by the flow controller, the output valve being arranged to control the flow rate of fluid out of the mixing chamber into the output conduit. Preferably the flow control means communicates e.g. by physical connection with the output valve.

Preferably, the mix controller is operable to control the relative proportion of fluid from each fluid input that is permitted into the mixing chamber.

Preferably, the mix controller controls input to the mixing chamber independently of the flow controller's control of flow output from the mixing chamber.

Preferably, the mixing chamber includes an input valve at each of the two inputs, each input valve being arranged to control the flow rate of fluid from its respective input into the mixing chamber. The two inputs may carry hot and cold water respectively. Preferably, the valves are controlled in a complementary fashion, i.e. varying the relative proportion of fluid from each input while maintaining a constant input flow rate. For example, the input flow rate to the mixing chamber may be kept constant with the mix controller able to cause all of the flow to come from one or other of the inputs or as a mixture of the two. Preferably, the ratio of the mixture is variable in a continuous, e.g. linear, fashion.

Thus, while the flow controller may be operable to allow fluid to flow through the tap assembly, the mix controller may be operable to control the proportions of flow inputs into the mixing chamber, i.e. the mix controller may control the content of the fluid flowing through the tap.

Preferably, the output conduit is a flexible tube extending from the mixing chamber to the housing mounted on the work surface. The housing is preferably located over a hole in the work surface through which the output conduit (flexible tube) passes. As explained above, the output conduit may feed a spray head mounted on the housing or may extend through a main spout to feed a nozzle detachably mounted to the end of the spout. In both cases, it is preferable that the tube is extendable away from the housing, e.g. by being slidable relative to it (i.e. through it) . This may be achieved by making the flexible tube longer than is necessary to reach the fluid outlet, with the excess length under the work surface when the tube is in a non-extended position.

Preferably, the flow and/or mix control means include physical connection to the valve or valves (e.g. cartridge valves) associated with the mixing chamber such that operation of the flow and/or mix actuator is directly transferred to operation of the valve or valves.

Preferably, the physical connection of the control means extends through the same hole (i.e. the single hole) in the work surface as the output conduit that carries fluid to the fluid outlet. By sharing this space, the number of components on view to the user (i.e. above the work surface) can be kept to a minimum, which may improve the overall appearance of the tap assembly.

In one preferred embodiment, the flow and mix control means are upstanding sleeves rotatable about an axis. The sleeves are preferably operably connected to the valve or valves associated with the mixing chamber.

In a most preferred configuration, the upstanding sleeves of the flow and mix control means are coaxial, i.e. concentric. The actuators may be rotatable rings coupled to their respective sleeve, each ring being rotatable by a protruding (e.g. radially protruding) lever.

Preferably, the rotation axis of the sleeves is coaxial with the hole in the housing through which the output conduit is arranged to travel. Thus, the output conduit may pass through the actuator sleeves on it route from the mixing chamber below the work surface to the fluid outlet above the work surface.

A longitudinal (axially extending) opening is preferably formed in each sleeve to receive the output conduit. The circumferential extent of the opening is preferably selected to avoid interference with (i.e. constricting movement of or affecting flow through) the output conduit. The axial extent of the opening is preferably selected to avoid excessive bending of the output conduit as it travels through the sleeves and out of the housing.

Thus, the flow rate and mix ratio of fluid output from the tap may be controllable by two rotatable controllers. The rotatable controllers may be located on top of one another to permit easy user access.

Fluid may arrive in the mixing chamber from each input through a respective input cartridge valve, e.g. of the conventional ceramic disc type, with the mix controller arranged to control the cartridge valves.

Typically, cartridge valves are operated (turned from off to full on) by rotating a control lever, e.g. through a quarter turn. Preferably, the control means of the mix controller is operably connected to the control levers of its respective cartridge valves. The operative connection may be geared to give the user increased control.

Fluid may exit from the mixing chamber into the output conduit through another cartridge valve, e.g. of the ceramic disc type, with the flow controller arranged to control this cartridge valve, e.g. in a similar way to the mix controller, described above.

The outputs of two input cartridge valves may be directly connected to, i. e. in fluid communication with, the input of an output cartridge valve. Thus, flow rate and mixing ratio of the output fluid flow can be controlled using three cartridge valves.

The flow and mix controllers may be combined. Such a combined mix/flow controller may include a common actuator for operating control means (which may be separate or combined) for controlling fluid input and output to the mixing chamber.

Preferably, the combined mix/flow controller includes both a common actuator and a common control means, thereby reducing the total number of components in the tap. The common actuator may be arranged to cause the common control means to exhibit different types of movement. A different type of movement may be associated with fluid input and output control. For example, the combined actuator may be horizontally rotatable and

vertically tiltable.

Different types of movement preferably communicate to the control means which of flow or mix control is to be operated. This communication may be physical. For example, the common control means may be a upstanding sleeve capable of rotational motion about its axis and linear motion along its axis, e.g. up and down.

The sleeve may be operably coupled to a single-lever mixing cartridge, e. g. of the conventional type where output flow rate and input mix proportion are controlled by manipulating a single lever. The movement of the sleeve is therefore preferably translated into movement of the control lever. For example, rotation of the sleeve may cause rotation of the control lever, and up and down movement of the sleeve may cause tilting of the control lever.

Second and third aspects of the invention may provide a tap and work surface assembly, including a mixer tap assembly mounted on a work surface, and a method of assembling the same, respectively.

According to a fourth aspect of the present invention there may be provided a mixer valve for mixing fluid received from first and second inputs to provide an output of mixed fluid, the mixer valve having: a first valve with an inlet in fluid communication with the first input; a second valve with an inlet in fluid communication with the second input; a third valve with an inlet in fluid communication with outlets of the first and second valves, and an outlet arranged to provide the output of mixed fluid; a mix controller arranged to operate the first and second valves; and a flow controller arranged to operate the third valve. The flow controller may therefore control the flow rate of fluid leaving the mixer valve. The flow controller may be able to completely close the third valve so that no fluid may leave the mixer valve. The operation of the flow controller is independent of the operation of the mix controller, so that the flow rate of fluid leaving the mixer valve may be controllable without affecting the mix proportion of the input fluid.

Preferably the mixer valve comprises a housing which contains the first, second and third valves. The housing may enclose a mixing chamber forming part of the fluid communication between the outlets of the first and second valves and the inlet of the third valve, the mixing chamber providing a space to promote thorough mixing so that the output is a substantially uniform mixture of the input fluids.

Preferably, the mix controller is arranged to operate the first and second valves in a complementary fashion. The first and second valves are preferably controlled by a common mix control element. The common mix control element may interconnect the first and second valves, so that when the first valve opens the second valve closes and vice versa. Such an interconnected controller promotes smooth variation of the input mix proportion. The combined flow rate from the fluid outlets of the first and second valves may be constant, although this may in practice depend on the fluid pressures of the inputs. This means that a constant input flow may be provided to the third valve, which therefore improves the control the third valves gives over output flow rate.

Preferably, one or more or all of the first, second and third valves are standard ceramic valve cartridges.

Preferably, each valve cartridge has its input in its base and a valve plate or plates arranged to open or close a fluid passageway between the base and the outlet to permit fluid flow out of the outlet when the passageway is open.

Preferably, each valve cartridge has an control spindle (e.g. upstanding from the cartridge) which is rotatable to open and close the valve. In the preferred embodiment, the bases of two of the valve cartridges are attached to the fluid inputs, i.e. a first valve cartridge may receive hot water, and the second valve cartridge may receive cold water. The output supplies of the first and second valve cartridges are preferably in fluid communication with the base of a third valve cartridge. In this arrangement, a mixing chamber may be provided in the volume (space) between the output suppliers of the first and second valve cartridge and the base of the third valve cartridge.

The output supply of the third valve may be directly connectable to a conduit or other fluid conveying means in order to carry fluid from the mixer valve to an outlet apparatus, e.g. tap. Of course, the mixer valve may be an internal or even integral component of such an outlet apparatus.

Preferably, the mix controller is arranged to rotate the control spindles of the first and second valve cartridges. Preferably, rotation of the control spindles is controlled in a complementary fashion, i.e. a common control element may interconnect them to cause rotation of both control spindles.

Preferably, a first mix controller operation causes the first valve cartridge to open and the second valve cartridge to close, and a second mix controller operation causes the second valve cartridge to open and the first valve cartridge to close. The common control element may be a rotatable shaft, and the first and second mix controller operations preferably correspond to opposite senses of rotation of the shaft.

The control spindles of the first and second valve cartridges may have gears attached to them that are operably connected to a main gear or other drive means rotatable by the mix controller. Preferably, the mix controller includes a rotatable shaft coupled to the main gear.

The gearing ratio between the main gear and gears attached to the control spindles may be 1:1, or there may be a step-up or step-down arrangement. Preferably the ratio is the same for both control spindles. For example, a step-down arrangement, which may give the rotatable shaft a larger operation angle than the valve cartridge control spindle, may be used to give improved leverage. Alternatively, a step-up arrangement, which may give the rotatable shaft a smaller operation angle than the valve cartridge control spindle, may be used to reduce the amount of movement required by the rotatable shaft. This can be useful where space is limited. Thus, a conventional quarter turn valve cartridge (having an operation angle of 90 between full open and full closed) may require the rotatable shaft to be rotated by more than 90 (e.g. 1200 or more) in a step-down mechanism, or by less than 900 (e.g. 60 or less) in a step-up mechanism.

The rotatable shaft is preferably adapted to be connected to a useroperated mechanism belonging to an outlet (e.g. tap) assembly. The useroperated mechanism may be a conventional rotary handle. The rotatable shaft may be connected to it by conventional means, e.g. a splined head matingly receivable in a correspondingly splined recess.

Preferably, the flow controller is arranged to rotate the control spindle on the third valve cartridge.

This may also be achieved by a gear attached to the control spindle which is operably connected (e.g. meshed with) a main gear or other drive means rotatable by the flow controller. As above, the gearing ratio between the main gear and gear attached to the control spindle may be 1:1, or there may be a step-up or step-down arrangement, depending on the constraints of leverage and/or space.

Preferably, the flow controller includes a rotatable shaft coupled to it main gear. The rotatable shaft is preferably adapted to be connected to a user-operated mechanism belonging to an outlet (e.g. tap) assembly.

For example, the user-operated mechanism may be a conventional rotary handle, or a tiltable lever, etc. Both the mix controller and flow controller may include rotatable shafts to operate their respective valve cartridges. In this case, the rotatable shafts may be coaxial. For example, the control shaft for one of the mix or flow controller may be a sleeve surrounding and rotatable relative to the rotatable shaft for the other controller. Preferably, the main gears attached to the rotatable shafts also rotate about a common axis.

Preferably they are axially displaced to avoid interfering with one another and cluttering the interior of the mixer valve. Since the gears attached to the valve cartridges have a limited rotational extent, the main gears may be provided with meshing teeth only around part of their circumference. This can save space inside the mixer valve and also lead to a more lightweight product.

A mixer valve as described above has general applicability, and may be incorporated in all types of mixer taps, or with the fluid outlet assemblies that require mixing. A fifth aspect of the present invention may also provide a fluid outlet assembly or mixertap that includes such a mixer valve. The mixer valve may be incorporated into the housing of such an assembly, or it may be located out of sight (e.g. behind a wall or below a work surface) . A sixth aspect of the present invention may provide a mixer tap connected to a work surface.

Examples of the present invention are discussed in detail with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of atap assembly according to a first embodiment of the invention; Fig. 2 is a side view of the tap assembly of Fig. 1; Fig. 3 is a cross-section taken along the line A-A in Fig. 2; Fig. 4 is a close-up perspective view of the interior of the mixing chamber housing shown in Fig. 1; Fig. 5 is another perspective view of the interior of the mixing chamber housing of Fig. 1; Fig. 6 is a perspective view of a tap assembly according to a second embodiment of the invention; Fig. 7 is a first cross-sectional view of the tap assembly of Fig. 6, in an "on" configuration; Fig. 8 is a second cross-sectional view of the tap assembly of Fig. 6, in an "off" configuration; Fig. 9 is a perspective view of a tap assembly according to a third embodiment of the invention; Fig. 10 is a front view of the tap assembly of Fig. 9; and Fig. 11 is a cross-section taken along the line B-B in Fig. 10.

Fig. 12 shows a side view of a mixer valve which is an embodiment of the invention in isolation; Fig. 13 shows a cross-section along the line D-D through the mixer valve of Fig. 12; Fig. 14 shows a cross-section taken along the line C-C of the mixer valve shown in Fig. 12; Fig. 15 shows another side view of the mixer valve shown in Fig. 12; Fig. 16 shows a cross-section through the line F-F of the mixer valve shown in Fig. 15; Fig. 17 shows a cross-section taken along the line E-E of the mixer valve shown in Fig. 15; Fig. 18 shows a perspective view of another mixer tap having a mixer valve which is an embodiment of the present invention; Fig. 19 shows a side view of the mixer tap shown in Fig. 18 when mounted on a work surface; and Fig. 20 shows a cross-section taken along the line G-G of the mixer tap shown in Fig. 19.

Fig. 1 shows a tap assembly 10 according to one embodiment of the invention isolated from its mounting position, e.g. next to a sink. The tap assembly 10 has a mixing chamber housing 12 which receives two fluid inputs 14,16 which are connected to hot and cold water supplies (not shown) respectively via connectors 19. The inputs 14,16 feed the base 15 of the mixing chamber housing 12; each input 14,16 supplies its own cartridge valve (not shown) inside the base 15. An output conduit 18 carries mixed fluid away from the mixing chamber housing 12 to a fluid outlet 34 at the end of an output spout 32. The output conduit 18 is a flexible pipe that loops around the bottom of the base 15 and passes through the interior of the output spout 32, which is a hollow rigid pipe made of suitable material (e.g. stainless steel, brass, etc.), arranged in a goose-neck configuration. The output conduit 18 feeds fluid to the fluid outlet 34, which is a conventional spray head. The fluid outlet 34 is detachably mounted to the output spout 32, and can be pulled down, i.e. away from the spout 32, to give the user flexibility in directing flow out of the outlet 34.

The output conduit 18 has extra length to accommodate this movement.

The mixing chamber housing 12 is connected to control housing 26 by an upstanding rigid tube 24. In use, as shown in Fig. 2, the base of control housing 26 rests on the top of a work surface 42, where it is secured in place by a backing nut 27. The upstanding tube 24 extends through a hole (not shown) in the work surface 42 so that the mixing chamber housing 12 and the loop of output conduit 18 are located out of sight below the work surface 42.

Tube 24 is hollow, and control housing 26 has a passageway therethrough to allow the output conduit 18 to travel from below the work surface 42 to the output spout 32 through the same hole in the work surface 42 as the tube 24. The tube 24 has a cut-out opening 25 which allows the output conduit 18 to be fed in below the control housing 26. A guiding tube 22 is attached to a ring 21 mounted on the tube 24 via a lug 23. The guide tube 22 controls the orientation and angle at which the output conduit 18 enters the tube 24. This prevents the edges of the cut-out hole 25 from interfering with the output conduit, and also prevents kinks from forming in the conduit.

Two radially protruding rotatable push levers 30,31 are mounted in the control housing 26 to communicate with the valves in the mixing chamber housing 12 as described below. The levers 30,31 rotate about a vertical axis extending through the tube 24. The levers 30,31 are located on top of one another, and their connections in the housing are covered by respective trim covers 28,29.

The upper lever 31 is arranged to control flow rate (output volume), whereas the lower lever 30 is arranged to control mix ratio, i.e. the relative proportion of fluid received from inputs 14,16.

Fig. 3 shows the mechanism by which the levers 30,31 communicate with the valves in the mixing chamber housing 12. Lower lever 30 is operably coupled to the head 35 of an upstanding rotatable sleeve 36. The base of sleeve 36 is connected to a annular block 46, which has a depending lug 55 connected to a set of radially protruding teeth 64, which are arranged to engage gears 58,60 associated with valve cartridges 52,54 for controlling the input mix ratio of fluid from inputs 14,16 (see Figs. 4 and 5).

Similarly, upper lever 31 is operably coupled to the head 37 of another upstanding sleeve 38 which lies inside and coaxial with sleeve 36 and tube 24. The base 40 of sleeve 38 has a splined through hole 43 bored therein which receives a correspondingly splined projection 45 from coupling block 44. Rotation of the sleeve 38 causes coupling block 44 to rotate. Coupling block 44 extends through annular block 46 and terminates in another set of radially protruding teeth 62 arranged to engage a gear 56 to operate a cartridge valve 50 associated with output flow rate (see Fig. 4) The valve cartridges 50,52,54 are housed in the base of the mixing chamber housing 12. A casing 17 attaches the base 15 to the tube 24 to prevent relative rotation therebetween, i.e. so that operating the levers 30,31 does not cause the entire mixing chamber housing 12 to rotate. Additionally, the cover 17 protects the gear connections, which protrude from the top of the base 15.

The rotatable sleeves 36,38, which act as physical control means that connect user operations above the work surface 42 to the control of valves below the work surface 42, also have cut-out openings along their length to overlap with the cut-out opening in tube 24. To allow for the rotation of the sleeves 36,38, their cut-out openings have a wider circumferential extent. This means that they do not interfere with the output conduit 18, even when rotated to control the cartridge valve(s) Figs. 4 and 5 show the operative connections in the mixing chamber housing 12. The base of the housing contains three standard cartridge valves 50,52,54 of the ceramic plate type. As is conventional, each valve has an input in its base, and an output near the top, and flow through the cartridges controlled by a valve which is opened and closed by rotating a control lever which projects from the top of the valve. In the illustrated embodiment, gears 56,58,60 are mounted on and rotatable with the control levers of the cartridges. Inputs 14,16 are connected to the inputs of two of the cartridges 52,54. The gears 58,60 of these cartridges 52,54 are operably connected to a common set of teeth 64. This allows for the input cartridges to be controlled in a complementary fashion, i.e. the common set of teeth 64 rotate between two limits corresponding to 100% (full) supply from input 14 and 100% (full) supply from input 16. Between these limits the cartridges 52,54 are open/closed in a linear (i.e. constant) fashion so that the total input volume remains constant and only the mix ratio (proportion of input 14 to input 16) varies.

The outputs of the two cartridges 52,54 connected to the inputs 14,16 are both connected to the input of the third valve cartridge 50. Mixing of the fluids occurs at this point. The third valve cartridge 50 is operated to control the flow rate of mixed fluid out of the mixing chamber housing 12 (i.e. through output conduit 18) Thus, the set of teeth 62 which are operably connected to the gear 56 on the third valve cartridge 50 is arranged to move the gear between two limits corresponding to oft, where no fluid flows through the cartridge (i.e. the valve is closed), and on, where the valve is fully open and maximum flow rate is achieved.

Figs. 6 to 8 illustrate a second embodiment of the invention. Components which are the same as those illustrated in the first embodiment are given the same reference numerals and are not described again.

In the second embodiment, the three valve cartridges of the first embodiment are replaced by a conventional single lever-type mixer valve 74, which is sits in an outer housing 71, secured by a ring 79. The inputs 14,16 and output conduit 18 are connected to the outer housing 71, from where they are fed to the mixer valve 74. A lever 76 is manipulated to permit fluid from the inputs 14,16 to enter a mixing chamber (not shown) in the mixer valve 74 in variable proportions. This is achieved by rotating the lever 76. The same lever 76 is also tiltable to control the amount of fluid released from the mixer valve 74 into the output conduit 18.

The mixer valve 74 is operated using an actuator lever 30a that is mounted on the control housing 26 above the work surface 42. The actuator lever 30a is coupled to an upstanding sleeve 72 which extends between the control housing 26 and the mixer valve 74. The sleeve 72 is rotatable and axially slidable relative to the tube 24 connecting the control housing 26 and mixer valve 74.

The actuator lever 30a is connected to the sleeve 72 via a V-shaped connector 73. The actuator lever is pivoted at a fulcrum 33 to enable the sleeve 72 to be pulled up and down. The lever 30a and fulcrum mechanism 33 are mounted on a rotatable ring 28, attached to the sleeve 72 so that the sleeve can be rotated by pushing the actuator lever 30a.

Figs. 7 and 8 show the connection between the control lever 76 of the mixer valve 74 and the base 75 of the sleeve 72. The control lever 76 is typically a box- like structure, and is contained within walls formed by the base of the sleeve 72 so that it is rotated with the sleeve 72. Outward projections 78 on the control lever 76 are received in slanted slots 77 in the walls that contain the lever 76. The slanted slots cause the lever to be tilted by the up and down movement of the sleeve 72. Fig. 7 shows an on configuration, where the sleeve 72 is at its lower position (actuator lever 30a pulled high) so that control lever 76 is tilted forward by the action of slot 77 against projection 78. Fig. 8 shows the off position with the sleeve 72 in its upper position (actuator lever 30a pushed down) where the control lever 76 stands upright.

As before, the sleeve 72 represents a physical control means connecting the actuator lever 30a with the mixer valve 74 and has a cut-out formed therein to enable the output conduit 18 to travel into the middle of tube 24, through the work surface 42 via the same hole as the tube 24 and sleeve 72 to enter the output spout 32.

A casing 70 attached the outer housing 71 to the tube 24 to prevent relative rotation therebetween, as described above. The casing 70 also protects the operative mechanism between the sleeve 72 and the control lever 76.

Figs. 9 to 11 illustrate a third embodiment of the invention, where the work surface which hides the mixer valve (i.e. the work surface through which the output conduit passes) is a vertical wall 102, e.g. a stud wall for mounting in a kitchen or other suitable area. Again, parts in common with the first or second embodiments are given the same reference numbers.

In the tap assembly 100 of the third embodiment, the housing 26 includes a flat base plate 106 which can be mounted on the wall 102 using screws 108. The output conduit 18 enters the cut out 25 in the tube 24 behind the wall 102 and is therefore guided horizontally through the wall into a conventional spout 104 to terminate at spray head 34.

Similar to the second embodiment, the third embodiment uses the single lever mixer valve 74, but in this case, the valve 74 is held in a horizontal configuration, with the lever 76 extending substantially horizontally.

The inner control sleeve 72 is movable axially (horizontally) and rotatably by the control lever 30b on the housing 26 using the same mechanism as the second embodiment.

Fig. 2 shows a mixer tap 10 that incorporates a mixer valve 20 that is an embodiment of the present invention. The mixer valve 20 includes a housing 15 arranged to receive fluid inputs via supply conduits 14,16 from main hot and cold water supply pipes respectively. An output conduit 18 extends away from the bottom of housing 15 and loops around the mixer valve 20 to be fed through a hole in the work surface 42 into a spout 32, terminating in a conventional spray head 34.

The spout 32 is mounted on the work surface via a housing 26. A rigid upstanding tube 24 extends through a hole in the work surface 42 and has the mixer valve 20 mounted on it via casing 17. The tube 24 is secured in place, i.e. prevented from rotating or moving axially with respect to the work surface 42, by a backing nut 27. A cut-out hole 25 is formed in the tube 24 to allow the output conduit 18 to pass into the tube and through a passageway in the middle of the housing 26. A guide pipe 22 is attached by a ring 21 and lug 23 (see Fig. 3) to the tube 24. The guide pipe 22 helps to orientate the output conduit 18 correctly so that it enters the cut-out 25 in the tube 24 without excessive bending or interference from the edges of the cut-out 25.

As shown in detail in Fig. 3, rotatable radially protruding levers 30,31 are operably connected to rotatable control elements 44,46 in the mixer valve 20.

The levers 30,31 are used to control the mixing proportion of hot and cold water received in the mixer valve and the output flow rate of fluid away from the mixer valve in the manner described in detail below.

In Fig. 3, it can be seen that housing 26 is formed in one piece with tube 24, and has control sleeves 36,38 coaxially mounted therein. The spout 32 is mounted in the top part of housing 26, where it is held in place by stopper 39. The control sleeves 36,38 are able to rotate relative to one another and to the tube 24. Inner control sleeve 38 has an upper head portion 37 connected to lever 31, and outer control sleeve 36 has an upper head portion 35 connected to lever 30. These connections are covered by respective trim covers 28,29. Both the control sleeves 36, 38 have cut-out portions arranged to overlap with the cut-out 25 in tube 24 to enable the output conduit 18 to pass cleanly into the inside of the housing 26. The gearing ratios described below may be selected to give a small operation angle to the control sleeves 36,38 so that cut-outs having a smaller circumferential extent can still fully overlap with the cut-out 25 in tube 24.

The base 40 of inner control sleeve 38 has a central, internally splined, through hole 43 arranged to matingly receive a correspondingly splined upstanding peg of flow control element 44. Thus, rotation of inner control sleeve 38 (via upper lever 31) causes rotation of flow control element 44.

Outer control sleeve 36 is connected to mix control element 46, so that rotation of lower lever 30 causes rotation of the mix control element 46.

As shown in Figs. 4 and 5, flow control element 44 has a toothed gear 62 radially protruding therefrom so as to mesh with a gear wheel 56 mounted on the control spindle (not shown) of a conventional ceramic disc valve cartridge 50. Meanwhile, mix control element 46, which is formed in the shape of an annulus, thereby allowing flow control element 44 to pass through it, has a depending connector plate 55 attached to another gear 64, whose radially protruding teeth mesh with gears 58,60 mounted on the control spindles (not shown) of two further ceramic plate valve cartridges 52,54. To maintain smooth rotation, the gears 62,64 controlled by the flow and mix control elements 44,46 are rotatably mounted on an upstanding axle 57, which is mounted in the base 15 of the mixer valve 20. Outer casing 17 securely attaches base 15 to a tube 24 to prevent the base 15 from rotating when the mix or flow control elements 44,46 are rotated. Casing 17 also acts as a protective cover for the gear mechanism.

Figs. 12 to 17 show the internal configuration of the mixer valve 20 in more detail. Briefly, the input fluid supplies 14,16 are respectively connected to the inputs of valve cartridges 252,254, whose control spindles are operated by mix control element 246. The outlets from these valve cartridges 252,254 are connected to the inlet of valve cartridge 250, whose control spindle is operated by flow control element 244. The outlet of valve cartridge 250 is connected to output conduit 18 so that any fluid flowing out of the mixer valve 20 is carried by output conduit 18 to spray head 34.

In detail, Fig. 12 shows the outlet tube 270 to which the output conduit 18 is attached. As shown in Fig. 13, a central passageway 272 is formed inside the base 215 to carry fluid out of the tube 270. Fluid is provided to the central passageway 272 from the outlet 273 of the valve cartridge 250 via a radial passageway 276. Fluid enters the inlet of valve cartridge 250 from upstanding passageway 278, which is in fluid communication with mixing chamber 274, which has an annular form, as shown in Fig. 14. Thus, fluid entering the mixing chamber 274 flows into valve cartridge 250 via upstanding passageway 278. If the valve is open, the fluid will leave the mixer valve 20 via passageways 272,276. The outlets of the valve cartridges that receive fluid input open into mixing chamber 274.

Fig. 15 shows another side view of the mixing valve 20, where the axial displacement of the valve cartridges 250,252,254 can clearly be seen. Valve cartridge 250 projects further out of the base 215 than valve cartridges 252,254. This allows the operating gears 262,264 to be axially displaced from one another. In fact it allows them to share a common axis whilst maintaining their independence. It also allows the mixer valve 20 to be compact in the radial direction.

The cross-section of Fig. 16 demonstrates how fluid is provided from the first two valve cartridges 252,254 to the mixing chamber 274. Fluid enters upright passageways 286,288 from input supplies 14,16. Input passageways 286,288 respectively carry the fluid into the inlets of valve cartridges 252,254. The outlets 290,292 of valve cartridges 252,254 are in fluid communication with the mixing chamber 274.

Fig. 17 shows that a single gear 264 is used to control both gears 258, 260 mounted on the control spindles 282,284 of valve cartridges 252,254. Since output flow rate is controlled separately by the action of gear 262 with gear 256 (which is shown mounted on the control spindle 280 of valve cartridge 250 in Fig. 17), there is no need for the mix control mechanism to exhibit any flow rate control. In other words, mix control mechanism need not cause both valves to be closed at the same time. That is, the mechanism represented by main gear 264 and valve cartridge gears 258,260 need only present the capability of varying the relative proportion of fluid permitted through valve cartridges 252,254. At one extreme, valve cartridge 252 is fully open and valve cartridge 254 is fully closed. The other extreme is represented by valve cartridge 252 being fully closed and valve cartridge 254 being fully open. By setting the initial position of the control spindles and main gear 264 correctly, the relative proportion of fluid permitted through valve cartridges 252,254 can be varied smoothly (e.g. linearly) between these two extremes. This is brought about by meshing equally sized gears 258,260 with the same main gear 264.

Figs. 18 to 20 show a mixer tap 300 with another mixer valve 200 according to the present invention. As shown in Fig. 19, mixer valve 200 is arranged to be mounted above the work surface 242 within the main housing 306,308 of a mixer tap assembly 300. As before, input supplies 214,216 are connected to the base 215 of the mixer valve 200. Radially protruding levers 230,231 are turned to rotate gears in the same way as shown in Figs. 12 to 17. As the mixer valve 200 is above the work surface in this embodiment, there is no need for control sleeves to connect the levers 230,231 to the mix and flow control elements. Connection is more direct, as shown in Fig. 18.

One difference in this embodiment is that the output from valve cartridge 250 is provided to a supply pipe 304 that extends out of the top of base 215 and is connected to the base of spout 302. Other than this, the internal mechanisms of the mixer valve 200 are the same as those illustrated in Figs. 12 to 17. Fig. 20 shows the presence of a mixing chamber 310.

In use, therefore, the user operates one of the radially protruding levers 30,31,230,231 to control the flow rate of fluid ejected from the mixer valve 20,200 to be carried to the spout or other outlet of the assembly in which the mixer valve is mounted. Independently of the flow rate, the user can control the mixing proportion (i.e. the temperature, where the fluid inputs are hot and cold water) of the ejected fluid by operating the other one of the radially protruding levers 30, 31, 230, 231.

Claims

Claims: 1. A mixer tap assembly having: mounting means for attaching the

assembly to a work surface; a mixing chamber positioned below the mounting means for mixing fluid receivable from two inputs which are in fluid communication with the mixing chamber; a fluid outlet positioned above the mounting means, which fluid outlet is located at the end of a spout; an output conduit in fluid communication with the mixing chamber for carrying mixed fluid to the fluid outlet; and a mix controller including mix valve means associated with the mixing chamber, the mix controller being operable to control the ratio of fluid received in the mixing chamber from the two inputs; wherein the mix controller further includes a mix actuator positioned above the mounting means and arranged to operate mix control means which is communicable with the mix valve means to perform the fluid input control; and wherein the mix control means and the output conduit pass through a bore in the mounting means.

2. A mixer tap assembly according to claim 1, further having a flow controller including flow valve means associated with the mixing chamber, the flow controller being operable to control fluid flow out of the mixing chamber into the output conduit, wherein the flow controller further includes a flow actuator positioned above the mounting means and arranged to operate flow control means which is communicable with the flow valve means to control the fluid flow out of the mixing chamber, wherein the flow control means passes through the bore in the mounting means.

3. A mixer tap assembly according to claim 1 or claim 2, wherein the output conduit is a flexible tube extending from the mixing chamber through the spout to the fluid outlet.

4. A mixer tap assembly according to claim 3, wherein the fluid outlet is detachably mounted to and extendable away from the end of the spout.

A mixer tap assembly according to any one of claims 2 to 4, wherein the flow and mix control means are

rotatable.

6. A mixer tap assembly according to any one of claims 2 to 5, wherein the flow and mix control means are sleeves.

7. A mixer tap assembly according to claim 6, wherein said sleeves are arranged concentrically to each other.

8. A mixer tap assembly according to claim 6 or claim 7, wherein a portion of the output conduit is located in the interior of part of the sleeves.

9. A mixer tap assembly according to claim 8, wherein each sleeve includes an axially extending opening formed in a circumferential surface thereof through which a portion of the output conduit passes.

10. A mixer tap assembly according to any one of claims 2 to 9, wherein each of the flow and mix control means are operably connected to their respective valves through a gear train.

11. A mixer tap assembly according to any one of claims 2 to 10, wherein the flow and mix actuators include rotatable rings coupled to the flow and mix control means, respectively.

12. A mixer tap assembly according to any one of claims 2 to 10, wherein the flow and mix controllers share a common flow and mix actuator.

13. A mixer tap assembly according to claim 12, wherein the flow and mix controllers share common flow and mix control means.

14. A mixer tap assembly according to claim 13, wherein the common flow and mix control means is a sleeve, said sleeve being rotatable and moveable along the axis of such rotation.

15. A mixer tap assembly according to any one of the preceding claims, arranged such that the mix control means is connected to the mix valve means associated with the mixing chamber such that actuation of the mix controller results in a change in the ratio of fluid from the two inputs into the mixing chamber while the total input flow rate into the mixing chamber from the two inputs is maintained.

16. A mixer tap assembly according to any one of the preceding claims, wherein the fluid outlet is a spray head nozzle.

17. A mixer tap assembly substantially as described herein with reference to and as illustrated in Figs. 1 to 5, Figs. 6 to 8, or Figs. 9 to 11 of the accompanying drawings.

18. A kit of parts for a mixer tap assembly having: mounting means for attaching the assembly to a work surface; a mixing chamber positionable below the mounting means for mixing fluid receivable from two inputs which are in fluid communication with the mixing chamber; a fluid outlet positionable above the mounting means, which fluid outlet is located at the end of a spout; an output conduit fluidly communicable with the mixing chamber for carrying mixed fluid to the fluid outlet; and a mix controller including mix valve means associated with the mixing chamber, the mix controller being operable to control the ratio of fluid received in the mixing chamber from the two inputs; wherein the mix controller further includes a mix actuator positionable above the mounting means and arrangeable to operate mix control means which is communicable with the mix valve means to perform the fluid input control; and wherein the mix control means and the output conduit are adapted to pass through a bore in the mounting means.

19. A tap and work surface assembly comprising: a mixer tap assembly according to any one of claims 1 to 17; and a work surface having a hole formed therethrough; the mounting means of the mixer tap assembly being attached to the work surface such that the bore of the mounting means is aligned with the hole in the work surface; wherein the mixing chamber is positioned below the work surface, and the fluid outlet and mix actuator are positioned on or above the work surface; and wherein the mix control means and the output conduit pass through the hole in the work surface.

20. A tap and work surface assembly according to claim 19, wherein the flow control means also passes through the hole in the work surface.

21. A tap and work surface assembly substantially as described herein with reference to and as illustrated in Figs. 1 to 5, Figs. 6 to 8, or Figs. 9 to 11 of the accompanying drawings.

22. A method of assembling a tap and work surface assembly, said tap and work surface assembly comprising a mixer tap assembly according to any one of claims 1 to 17 and a work surface with a hole formed therethrough, wherein said method comprises the steps of: attaching the mixer tap assembly to the work surface via said mounting means, such that the mixing chamber is positioned below the work surface, and the fluid outlet and mix actuator are positioned on or above the work surface; and arranging the mix control means and output conduit such that they pass through the hole in the work surface.

23. A method of assembling a tap and work surface assembly according to claim 22, further comprising the steps of: attaching the mixer tap assembly to the work surface via said mounting means such that the flow actuator is positioned on or above the work surface; and arranging the flow control means such that it passes through the hole in the work surface.

24. A mixer tap assembly having: a mixing chamber mountable below a work surface for mixing fluid receivable from two inputs which are in fluid communication with the mixing chamber; a fluid outlet mountable on or above the work surface; an output conduit in fluid communication with the mixing chamber to carry mixed fluid to the fluid outlet; a flow controller operable to control fluid flow out of the mixing chamber into the output conduit; and a mix controller operable to control fluid input received in the mixing chamber; wherein: the flow controller has a flow actuator that is mountable on or above the work surface and arranged to operate flow control means which are communicable with the mixing chamber through the work surface to control fluid flow out of the mixing chamber; the mix controller has a mix actuator that is mountable on or above the work surface and arranged to operate mix control means which are communicable with the mixing chamber through the work surface to perform the fluid input control; and the flow control means, mix control means and output conduit are adapted to share a common path through the 25. A kit of parts for a mixer tap assembly having: a mixing chamber mountable below a work surface for mixing fluid receivable from two inputs which are in fluid communication with the mixing chamber; a fluid outlet mountable on or above the work surface; an output conduit fluidly communicable with the mixing chamber to carry mixed fluid to the fluid outlet; a flow controller operable to control fluid flow out of the mixing chamber into the output conduit; and a mix controller operable to control fluid input received in the mixing chamber; wherein: the flow controller has a flow actuator that is mountable on or above the work surface and arrangeable to operate flow control means which are communicable with the mixing chamber through the work surface to control fluid flow out of the mixing chamber; the mix controller has a mix actuator that is mountable on or above the work surface and arrangeable to operate mix control means which are communicable with the mixing chamber through the work surface to perform the fluid input control; and the flow control means, mix control means and output conduit are adapted to share a common path through the 26. A tap and work surface assembly comprising a mixer tap assembly according to claim 24 and a work surface, wherein the mixing chamber is mounted below the work surface and the fluid outlet, flow actuator and mix actuator are mounted on or above the work surface, wherein the flow control means, mix control means and output conduit share a common path through the work surface.

27. A method of assembling a tap and work surface assembly, said tap and work surface assembly comprising a mixer tap assembly according to claim 24 and a work surface; wherein said method comprises the steps of: mounting the mixing chamber below the work surface; mounting the fluid outlet, flow actuator and mix actuator on or above the work surface; and arranging the flow control means, mix control means and output conduit such that they share a common path through the work surface.

28. A mixer valve for mixing fluid received from first and second inputs to provide an output of mixed fluid, the mixer valve having: a first valve with an inlet in fluid communication with the first input; a second valve with an inlet in fluid communication with the second input; a third valve with an inlet in fluid communication with outlets of the first and second valves, and an outlet arranged to provide the output of mixed fluid; a mix controller arranged to operate the first and second valves; and a flow controller arranged to operate the third valve.

29. A mixer valve according to claim 28, wherein the mix controller includes a common mix control element to operate the first and second valves.

30. A mixer valve according to claim 29, wherein the common mix control element is a rotatable shaft.

31. A mixer valve according to claim 30, wherein the flow controller includes a rotatable shaft to operate the third valve, and the rotatable shaft of one of the flow controller or mix controller is a sleeve surrounding and rotatable relative to the rotatable shaft of the other one of the flow controller or mix controller.

32. A mixer valve according to any one of claims 28 to 31, arranged such that the mix controller is connected to the first and second valve such that actuation of the mix controller results in simultaneous operation of the first and second valves.

33. A mixer valve according to any one of claims 28 to 32, wherein each of the first and second valves has a control spindle with a gear attached to it that is operably connected to a main gear rotatable by the mix controller.

34. A mixer valve according to claim 33, wherein the main gear rotatable by the mix controller has teeth only around part of its circumference.

35. A mixer valve according to any one of claims 28 to 34, wherein the third valve has a control spindle with a gear attached to it that is operably connected to a main gear rotatable by the flow controller.

36. A mixer valve according to claim 35, wherein the main gear rotatable by the flow controller has teeth only around part of its circumference.

37. A mixer valve substantially as described herein with reference to and as illustrated in Figs. 1 to 5, Figs. 12 to 17, or Figs. 18 to 20 of the accompanying drawings.

38. A mixer tap assembly including a mixer valve, the mixer valve being according to any one of claims 28 to 37.

39. A mixer tap assembly substantially as described herein with reference to and as illustrated in Figs. 1 to or Figs. 18 to 20 of the accompanying drawings.

40. A tap and work surface assembly comprising a mixer tap assembly connected to a work surface, the mixer tap assembly being according to claim 38 or claim 39.