Patent Description:
It is well known to have ablutionary fittings that mix hot and cold water, and provide the mixed water to one or more output devices such as taps, faucets, handheld spray heads or showerheads. One common type of fitting uses a mixer valve to mix the hot and cold water, whilst another type of fitting uses a thermostatic cartridge. The thermostatic cartridge is fitting in a housing that has a chamber for receiving the cartridge, inlets for coupling the cartridge to water supply pipes, and outlet(s) for coupling to output device(s). A decorative cover is fitted over the housing after installation. <CIT> discloses an example of a thermostatic mixer tap.

The supply pipes provide water at different temperatures, forming a temperature differential to be formed within the fitting. It is known to generate an electric current from such temperature differentials, using thermoelectric modules. <CIT> discloses an example of a mixer tap using thermoelectric modules for generating power from the temperature differential between hot and cold water supplies.

The invention is given by the appended claims.

According to a first aspect of the invention, there is provided an apparatus for generating an electrical current from a temperature differential in an ablutionary fitting, the apparatus comprising: a heat transfer plate having a projection configured to directly contact water carried in a first region of the fitting; and a thermoelectric module comprising one or more thermoelectric elements, the thermoelectric elements configured to be thermally coupled between the heat transfer plate and a housing of the ablutionary fitting in a second region of the ablutionary fitting, the thermoelectric elements also being configured to generate electricity from a temperature differential between water carried the first and second regions of the ablutionary fitting.

The apparatus allows a thermoelectric module to be integrated into an ablutionary fitting with a mixer cartridge in a space and cost effective manner, at low cost and without significant redesign. The ablutionary fitting may be a thermostatic ablutionary fitting.

The plate allows the location and orientation of the temperature differential to be moved for easy integration of the thermoelectric module into the housing of an ablutionary fitting. Heat transfer from the first region to the thermoelectric module is carried out by direct contact with the heat transfer plate. However, since the heat transfer occurs at the inlet of the thermoelectric cartridge, no water is diverted away from the cartridge during operation of the apparatus. Accordingly, use of the apparatus may have minimal effect on the operation of the ablutionary or plumbing system. The thermoelectric module is located at the second region, and so it is not necessary to move this heat. The apparatus recovers energy (heat) that would otherwise go to waste and generates useful electricity.

The projection may be configured to extend through an aperture formed in the housing of the ablutionary fitting, into an inner chamber of the ablutionary fitting.

The water carried in the first region may be at a first temperature, and the water carried in the second region may be at a second temperature, different to the first.

The heat transfer plate may comprise a first portion including the projection, and a second portion extending away from the first portion. The second portion may be configured to be thermally coupled to the thermoelectric elements. The first portion may also be thermally coupled to the second portion.

The projection may extend along a first direction. The second portion may extend in a direction substantially perpendicular to the first direction.

The second portion may be substantially planar. The projection may extend out of the plane of the heat transfer plate.

The projection may comprise a plurality of surfaces arranged to extend into a chamber formed in the first region of the ablutionary fitting.

The apparatus may comprise a seal to form a water-tight seal between the first portion of the heat transfer plate and the housing of the ablutionary fitting, around the projection.

The heat transfer plate may at least in part form a seat for locating the seal.

The thermoelectric module may be configured to be in direct contact with the housing of the ablutionary fitting.

The apparatus may comprise an electrical socket electrically coupled to the thermoelectric elements and configured to be connected to an output load.

The socket may be mounted on a support member, and may be electrically coupled to the thermoelectric elements by wires.

The output load may comprise one or more light emitting devices.

The apparatus may comprise: a controller configured to control the output from the socket and/or the operation of the output load, in dependence on a voltage generated by the thermoelectric module.

The controller may be configured to control electrical output from the socket and/or the output load, in dependence on the stability of the voltage generated by the thermoelectric module.

The controller may be configured to control the output from the socket and/or the operation of the output load in two modes comprising: a first mode when the output is stable, and a second mode when the output is unstable.

The output in the first mode may be dependent on the magnitude of the voltage.

The heat transfer plate may have a first side and a second side. The projection may extend from the first side of the heat transfer plate. The first side of the heat transfer plate may also abut the thermoelectric module.

The apparatus may be configured to be installed in an ablutionary fitting including a mixer cartridge.

According to a second aspect of the invention, there is provided an ablutionary fitting comprising: a housing defining: a first inlet for receiving water at a first temperature, a second inlet for receiving water at a second temperature, different to the first, and an internal chamber for receiving a cartridge for mixing the water for the first and second inlet; and an apparatus according to the first aspect, mounted on an exterior surface of the housing, the apparatus for generating an electrical current from a temperature differential between the first inlet and the second inlet.

The housing may comprise an aperture extending through the housing into the internal chamber in a first region of the ablutionary fitting.

The housing may at least in part define a seat for locating the seal.

The ablutionary fitting may comprise an indent in the housing arranged to receive the thermoelectric module, the indent forming the second region.

The internal chamber and housing may be substantially cylindrical, extending in an axial direction.

The ablutionary fitting may comprise a wedge shaped projection to form a planar surface for mounting the thermoelectric module and heat transfer plate.

The housing may define a sub-chamber formed within the internal chamber at a first axial position along a length of the cylinder, where water received at the first inlet enters the internal chamber to enter the cartridge, the sub-chamber forming the first region.

The sub-chamber may extend around at least a portion of the circumference of the cylinder.

At least a portion of the sub-chamber may overlap the second region in a circumferential direction. The first region and second region may be spaced along the axial direction.

The housing may define an inlet passage for directing water from the second inlet to a second sub-chamber formed within the inner chamber, where water from the second inlet enters the cartridge. The housing may further define an outlet passage for directing water from the cartridge to an outlet device. The inlet passage and outlet passage may extend along the axial direction and may be circumferentially spaced from each other. The second region may be circumferentially between the inlet passage and the outlet passage.

The ablutionary fitting may comprise a second apparatus according to the first aspect.

The first and second apparatus may be circumferentially spaced around the housing, on opposite sides of the inlet passage.

The first sub-chamber may circumferentially overlap the first and second apparatus, such that the projection of the heat transfer plate of the first apparatus and the projection of the heat transfer plate of the second apparatus both project into the same sub-chamber.

The ablutionary fitting may include a mixer cartridge. The mixer cartridge may be a thermostatic cartridge.

It will be appreciated that features of the ablutionary fitting discussed in relation to the first apparatus may also apply to the second apparatus.

Embodiments of the invention will now be described, by way of example only, with reference to the drawings, in which:.

<FIG> illustrates an example of a mixer shower fitting <NUM>, which is used as an example to illustrate various embodiments. <FIG> and <FIG> illustrate the fitting <NUM> in sectional view. The two views of <FIG> and <FIG> are taken at <NUM> degrees to each other.

The shower fitting <NUM> has a substantially cylindrical body <NUM> formed by a cylindrical housing defining a longitudinal axis X-X. The body/housing <NUM> is secured to a mounting plate <NUM>, which in turn is fitted to a wall or other support surface (not shown). Thus, in use, the axis X-X projects out of the wall or support surface.

In the below, reference will be made to the top/front and bottom/rear of the fitting <NUM> and various components of the fitting <NUM>. These terms are defined along the axis X-X, with respect to the plate <NUM>. Therefore, the "bottom", "base" or "rear" of an element is the end closest to the plate <NUM>, whilst the "top" or "front" is the opposing end, spaced from the plate <NUM>. The upwards/downwards and forwards/backwards directions will also be defined along this axis X-X with upwards/forwards being along the axis X-X away from the plate <NUM> and down/backwards being along the axis X-X towards the plate <NUM>.

In one example, the body <NUM> is secured to the mounting plate <NUM> by screws <NUM>, however it will be appreciated that this is by way of example only, and various mechanisms for securing the body <NUM> to the plate <NUM> will be understood by the person skilled in the art. For example, any suitable mechanical fixing may be used, or interengaging projections may be used.

As shown in <FIG>, the body <NUM> and plate <NUM> define a pair of inlets 9a,b for connecting to water supply pipes (not shown). In this example, a first inlet 9a is arranged to connect to a hot water supply, and the second inlet 9b, is connected to a cold water supply.

Each of the body inlets 9a,b is coupled to a respective inlet passage 13a,b defined in the housing, which in turn has an opening 15a,b into an inner chamber <NUM> defined in the housing. The inlet passages 13a,b extend along the axis X-X, and are formed in projections extending radially out from the body <NUM>. The two inlet passages 13a,b are formed at diametrically opposed positions around the body <NUM>.

The chamber openings 15a,b are controlled by check valves 17a,b, which are biased to close the chamber openings 15a,b. Under sufficient water pressure, the check valves 17a,b open, to permit passage of water into the chamber <NUM>. In one example, the check valves 17a,b may open with a pressure of <NUM> bar or more.

A thermostatic mixer cartridge <NUM> is received in the chamber <NUM> to mix the hot and cold water. In <FIG>, the cartridge <NUM> is shown in cut-through view, whilst in <FIG>, the outer surface of the cartridge <NUM> is shown. The cartridge <NUM> has hot and cold inlets (not shown) axially aligned with the chamber openings 15a,b to receive water from the body inlets 9a,b.

The thermostatic mixer cartridge <NUM> is substantially cylindrical in shape and extends along the axis X-X and has a single outlet <NUM> for mixed water at its base. The body <NUM> defines an outlet chamber <NUM> into which the outlet <NUM> opens. A control <NUM> is provided to control the mixing of the water, to vary the temperature at the outlet <NUM>.

The check valves 17a,b, thermostatic mixer cartridges <NUM> and controls <NUM> are known in the art.

As best shown in <FIG>, a number of seals 33a-c are formed around the outer surface of the cartridge <NUM>, spaced along the length of the cartridge <NUM>. The seals 33a-c engage respective portions 37a-c of the inner surface <NUM> of the housing <NUM>, defining the inner (internal) chamber <NUM>.

The surface portions 37a-c and seals 33a-c are annular, extending around the full circumference of the chamber <NUM> and cartridge <NUM>, and thus divide the inner chamber <NUM> into two sub-chambers 11a,b. A first sub-chamber 11a is axially aligned with the first chamber opening 15a, from the first inlet passage 13a and the hot water inlet of the cartridge <NUM>.

A second sub-chamber 11b is axially aligned with the chamber opening 15b, from the second inlet passage 13b and the cold water inlet of the cartridge <NUM>.

The second sub-chamber 11b is axially forward of the first sub-chamber 11a, therefore, as best shown in <FIG>, the second inlet passage 13b extends axially further forward than the first inlet passage 13a.

As best shown in <FIG>, the body <NUM> defines a pair of outlet openings <NUM>,b. Each outlet opening 27a,b provides mixed water from the mixer cartridge <NUM>, and may be connected to a different output device (not shown). For example, a first outlet 27a may connect to an overhead showerhead, and a second outlet 27b may connect to a handheld unit.

Each outlet opening 27a,b is connected to the outlet chamber <NUM> by a respective outlet passage 29a,b defined in the housing <NUM>. The outlet passages 29a,b extend parallel to the axis X-X, with water flowing in a direction away from the base <NUM>. Thus, the outlet openings 27a,b are arranged on the side of the body <NUM>.

Within each outlet passage 29a,b, a valve chamber 31a,b is formed. The valve chambers 31a,b receive a respective valve module (not shown), to control the flow to the outlets 27a,b.

The outlet passages 29a,b are formed at diametrically opposed positions around the body <NUM>. Like the inlet passages 13a,b. the outlet passages 29a,b are formed in projections extending radially out from the body <NUM>. However, unlike the inlet passages 13a,b, the outlet passages 29a,b extend the same length along the axial direction X-X.

The outlet passage 29a,b are spaced from the inlets passages 13a,b by <NUM> degrees around the axis X-X, thus the four passages 13a,b,29a,b are equally spaced around the body <NUM> of the fitting <NUM>.

Within the fitting <NUM>, a temperature differential exists between the hot water at the first inlet 9a and the cold water at the second inlet 9b. The fitting <NUM> includes an apparatus <NUM> to generate electrical power using this differential.

In the example shown, the apparatus <NUM> includes a pair of thermoelectric devices <NUM>, provided on the exterior surface of the body <NUM>. A first thermoelectric device <NUM> is provided between the first outlet passage 29a and the first inlet passage 13a, and a second thermoelectric device <NUM> is provided between the first inlet passage 13a and the second outlet passage 29b.

<FIG> shows the fitting <NUM>, with the housing <NUM> cut-away to show a sectional view of the first thermoelectric device <NUM>. It will be appreciated that the construction of the first thermoelectric device <NUM> is the same as the second <NUM>.

The thermoelectric device <NUM> includes a respective heat transfer plate <NUM> and a thermoelectric module <NUM> provided between the heat transfer plate <NUM> and the housing <NUM>.

<FIG> shows an example of a heat transfer plate <NUM> in more detail. The plate <NUM> is substantially rectangular in shape, with a planar body <NUM>, and is formed of a thermally conductive material.

The body <NUM> includes a wedge shaped projection <NUM> on its exterior surface, to provide a flat surface on which to mount the plate <NUM>. The projection <NUM> includes a recess or indent <NUM>, shaped to receive the thermoelectric module <NUM>. The recess <NUM> is axially aligned with the first sub-chamber 11a of the inner chamber <NUM> of the housing, where the hot water passes into the thermostatic cartridge <NUM>. The recess is circumferentially positioned between the projection forming the first inlet passage 13a and one of the outlet passages 29a,b.

The body <NUM> is also formed of a thermally conductive material, such that a first side <NUM> of the thermoelectric module <NUM> is coupled to the body, which is turn is heated by the water in the first sub-chamber 11a and/or the inlet passage 13a.

In the position of the recess <NUM>, the housing <NUM> may be of reduced thickness to improve the thermal conduction of the hot water to the thermoelectric module <NUM>.

The heat transfer plate <NUM> has a first side <NUM> which, in the assembled fitting <NUM>, abuts the housing <NUM> and thermoelectric module <NUM>, and an opposing, outward facing, second side <NUM>.

The heat transfer plate <NUM> has a first portion <NUM>, which, in the assembled fitting <NUM>, overlies the recess <NUM>. Thus the thermoelectric module <NUM> is fitted between the first portion <NUM> of the heat transfer plate <NUM>, and the housing <NUM> in the region of the first sub-chamber 11a of the fitting <NUM>.

The heat transfer plate <NUM> has a second portion <NUM> extending axially forward from the first portion <NUM>, past the projection 37b dividing the first sub-chamber 11a from the second sub-chamber 11b, and into a region of the housing <NUM> overlapping the second sub-chamber 11b.

At the region where the heat transfer plate <NUM> overlaps the second sub-chamber 11b, an aperture <NUM> extending through the housing <NUM> into the second sub-chamber 11b is formed. The heat transfer plate <NUM> includes a corresponding projection <NUM> that extends from the first side <NUM> of the plate <NUM>, through the aperture <NUM>, into the second sub-chamber 11b.

In the example shown, the projection <NUM> is substantially rectangular in shape. It has a sidewall <NUM> extending around the outside of the projection defining a hollow void <NUM> within. The void <NUM> is closed by an end wall <NUM> at the radially inner end, and open to the outer surface <NUM> of the heat exchange plate <NUM> at the radially outer end.

The sidewall <NUM> and end wall <NUM> defines a first pair of parallel spaced surface 71a,b, a second pair of the parallel spaced surface 73a,b extending perpendicular to the first pair 71a,b, and connecting the ends of the first pair 71a,b, and an end surface <NUM>. These inner (wet) surfaces 71a,b,73a,b,<NUM> extend into the second sub-chamber 11b, and directly contact the cold water in the second sub-chamber 11b. Opposing these surfaces is a radially outer (dry) surface <NUM>.

Around the edge of the aperture <NUM> in the housing <NUM>, a step <NUM> is formed. This step <NUM> forms a seat for locating a seal <NUM> that seals between the housing <NUM> and the heat transfer plate <NUM>, preventing leakage from the second sub-chamber 11b though the aperture <NUM>.

As discussed above, the heat transfer plate <NUM> is formed of a thermally conductive material. Therefore, the cold water in the second sub-chamber 11b is thermally coupled to the second side <NUM> of the thermoelectric module <NUM>, opposite the first side <NUM>.

In this way, the thermoelectric module <NUM> is provided at a first region of the fitting <NUM>. The first side <NUM> of the thermoelectric module <NUM> is thermally coupled to the hot water in that first region (first sub-chamber 11a and/or inlet passage 13a) of the fitting <NUM>, through the body <NUM>. The second side <NUM> of the thermoelectric module <NUM> is thermally coupled to the cold water in a separate, different region, by use of a heat transfer plate <NUM> to transfer heat to the first region.

The heat transfer plate <NUM> is secured to the body by screws (not shown) extending through screw holes <NUM> in the plate <NUM>, into the housing <NUM>. The heat transfer plate <NUM> has a first screw hole 89a formed through it axially forward of the projection <NUM>. A second screw hole 89b is formed at the opposite end of the heat transfer plate <NUM> (in the axial direction). The second screw hole 89b may be partially open, forming a hoop, as shown in <FIG>.

A thermal washer plate <NUM> is also provided. The washer plate <NUM> is formed of a non-thermally conductive material. The plate has a planar body <NUM> that has end portions 93a which sit between the heads of the screws (not shown) and the heat transfer plate <NUM>, and a connecting portion 93b extending between the end portions 93a.

The thermal washer plate <NUM> provides a surface for the screws (not shown) to bear against. Furthermore, the thermal washer plate <NUM> has annular projections <NUM> extending into the screw holes 89a,b such that the projections <NUM> sit between the screws (not shown)and the heat transfer plate <NUM>. The thermal washer plate <NUM> ensures that the screws (not shown), which are thermally coupled to the housing <NUM>, are thermally isolated from the heat transfer plate <NUM>, to prevent heat loss through the screws.

The thermal washer plate <NUM> also includes a cylindrical projection <NUM> projecting outward from the body <NUM>, in the opposite direction to the projections <NUM>. The projection ensures that the washer plate <NUM> can only be installed in the correct orientation.

<FIG> schematically illustrates the circuit formed at one of the thermoelectric devices <NUM> in more detail. The thermoelectric modules <NUM> comprise a plurality of thermoelectric elements 97a-c (three are shown for illustrative purposes, but there could be any number). The thermoelectric elements 97a-c are arranged thermally in parallel between the heat transfer plate <NUM> and the housing <NUM>, and are connected electrically in series. The thermoelectric elements 97a-c may comprise, or consist essentially of, any suitable thermoelectric material(s) such as bismuth telluride.

Each thermoelectric module <NUM> is connected to a pair of electrical wires 99a,b. Each pair of electrical wires 99a,b is arranged to carry electric current to and from one of the thermoelectric modules <NUM>.

Where multiple thermoelectric modules <NUM> are provided, the separate modules may similarly be connected so that the separate elements of each module remain electrically in series, and thermally in parallel.

The electrical wires 99a,b may connect the thermoelectric module(s) <NUM> to any electrical component(s) or device(s) <NUM>. For instance, electricity generated in the thermoelectric module(s) <NUM> may be used to power one or more lights, e.g. LED lights. The light(s) may be decorative or ornamental. The light(s) may for example be operable to provide supplemental and/or entertaining illumination in a room such as a bathroom, wetroom or washroom, e.g. within a shower enclosure or shower cubicle. The light(s) may be indicative of the operating state of an ablutionary fitting or plumbing fixture such as a shower unit, a showerhead, a sprayer, a mixer valve, (e.g. a thermostatic mixer valve), a tap, a faucet, a toilet, a flush for a toilet or a bidet.

The thermoelectric module(s) <NUM> may be electrically connected to an electricity storage device (not shown) such as a battery or a capacitor for later use according to user demand.

By powering the electrical component(s) or device(s) <NUM> using electricity generated from a temperature differential, there may be no need to connect the electrical component(s) or device(s) to the mains or another electricity supply. For example, this may alleviate to some extent potential problems in connecting the electrical component(s) or device(s) to the mains or another electricity supply when the electrical component(s) or device(s) is/are located in a wet environment such as a shower enclosure, a shower cubicle, a bathroom, a washroom or a wetroom.

As best shown in <FIG> and <FIG>, the apparatus <NUM> includes an electrical socket <NUM>. The electrical socket <NUM> is provided to enable easy connection between the thermoelectric devices <NUM> and the output device <NUM>.

In the example shown, the socket <NUM> is provided on a support member <NUM> extending from the backing plate <NUM>. The support member <NUM> is substantially planar in shape, extending perpendicular to the axial direction X-X. The socket <NUM> is formed on the support member <NUM>, such that it is spaced from the housing <NUM> for easy access and connection.

The socket <NUM> is formed by a projection <NUM> formed on the support member <NUM>. The projection <NUM> comprises a cylindrical side wall <NUM> extending around an opening in the support member <NUM>, and in a direction axially forward from the support member <NUM>. On top of the side wall <NUM> (i.e. axially forward), a body member <NUM> is formed. The body <NUM> has a front portion 111a extending axially forward from the sidewall <NUM>, and a rear portion 111b extending into the space <NUM> defined within the sidewall <NUM>. The rear portion 111b only extends a portion of the length of the sidewall <NUM>, such that a recess <NUM> is formed in the rear surface of the support member <NUM>.

The front portion 111a of the body member <NUM> has an outer wall <NUM> that extends radially outside the sidewall <NUM>, and tapers inwards as it extends forwards along the axial direction. The outer wall <NUM> extends rearward, past the end of the sidewall <NUM>, thus forming an outer lip 117a on its rear end.

A pair of pogo pin connectors <NUM> are provided. The pogo pin connectors 119extend through the body member <NUM> forward of the projection <NUM>, and rearward into the recess <NUM>.

In use, the wires 99a,b extend from the thermoelectric modules <NUM>, and connect to the pogo connector pins <NUM> on the rearward side of the support member <NUM>. In one example, openings (not shown) may be provided in the support member <NUM> for the wires 99a,b to pass through. In other examples, the wires 99a,b may simply pass round the edge of the support member <NUM>.

Operation of the apparatus <NUM> will now be described. There is a temperature difference between the cold water flowing in the second sub-chamber 11b and the hot water flowing in the first sub-chamber 11a and/or hot water inlet passage 13a.

In the UK, a hot water supply may typically have a temperature of around <NUM> and a cold water supply may typically have a temperature of around <NUM>. The exact temperatures of the hot water supply and/or the cold water supply may vary with location, e.g. country, season, time of day and/or weather conditions.

At the location of the thermoelectric device(s) <NUM>, the temperature difference between the cold water flowing in the first pipe <NUM> and the hot water flowing in the second pipe <NUM> will depend for example on the proximity of the apparatus <NUM> to the hot water supply and/or the cold water supply.

The temperature difference between the cold water flowing in the second sub-chamber 11b and the hot water flowing in the first sub-chamber 11a and/or hot water inlet passage 13a may be up to or at least <NUM>, up to or at least <NUM>, up to or at least <NUM>, up to or at least <NUM> or up to or at least <NUM>.

The heat plate <NUM> enables the position of the temperature differential to be moved by conducting the temperature of the cold water to a different location. Heat is also conducted from the first sub-chamber 11a and/or hot water inlet passage 13a through the housing <NUM> of the fitting <NUM>. As a consequence of the temperature difference between the water flowing in the second sub-chamber 11b and water flowing in the first sub-chamber 11a and/or hot water inlet passage 13a, a temperature difference exists between the first portion <NUM> of the heat transfer plate <NUM> and the housing <NUM> of the fitting <NUM>.

In the illustrated example embodiment, the temperature difference between the first portion <NUM> of the heat transfer plate <NUM> and the housing <NUM> of the fitting extends radially outward from the axial direction X-X. On the other hand, the temperature difference between the first sub-chamber 11a and/or the hot water inlet passage and the second sub-chamber 11b is parallel to the axial direction X-X.

The thermoelectric module <NUM> is disposed between the first portion <NUM> of the heat transfer plate <NUM> and the housing <NUM> of the fitting 1in the region of the first sub-chamber 11a. The thermoelectric module <NUM> is configured to generate electricity as a result of the temperature difference between the first portion <NUM> of the heat transfer plate <NUM> and the housing <NUM>. The generated electricity is transported by the electrical wires 99a,b to any electrical component(s) or device(s).

It will be appreciated that although the embodiment discussed above has a pair of thermoelectric devices <NUM>, each with a single thermoelectric module <NUM>, any number of separate devices <NUM> may be provided, each device having any number of modules <NUM>.

<FIG> illustrates one illustrate example of how an output device <NUM> may be incorporated into the fitting.

As shown in <FIG>, the ablutionary fitting <NUM> may have a cover plate <NUM> arranged to fit over the housing <NUM>. The cover plate has a cylindrical section 121a arranged to cover the housing <NUM>, and a planar section 121b extending radially outward from the cylindrical section 121a.

The cover plate <NUM> may be secured to the backing plate <NUM> by any suitable means, such as interengaging projections or screws. The cover plate <NUM> may define a user control device <NUM> to operate the control <NUM> of the thermostatic cartridge and may also include other user control devices (not shown), such as push buttons, for operating valves to open and close the outlets 27a,b.

Within the cover plate <NUM>, the output device <NUM> is also formed. In this case, the output device <NUM> comprises a printed circuit board (PCB) <NUM>. One or more LEDs <NUM> are mounted on the PCB, with a cover lens <NUM> provided over the LEDs. The PCB <NUM> contacts the pogo pins <NUM> of the socket <NUM>. Electrical tracks (not shown) formed in the PCB <NUM> provide an electrical connection between the pogo pins <NUM> and the LEDs <NUM>.

In the example shown, the LEDs are provided in the planar portion 121b of the cover <NUM>, adjacent the join between the planar portion 121b and the cylindrical portion 121a. The LEDs <NUM> may extend around the full circumference of the cylindrical portion 121a, or only a portion. Alternatively, the LEDs <NUM> may be provided in other positions, anywhere on or near the fitting <NUM>. The cover <NUM> includes a transparent portion <NUM> overlying the LEDs <NUM>.

The cover <NUM> also includes internal formations <NUM> to form an enclosed chamber <NUM> around the PCB <NUM>. The enclosed chamber <NUM> has an opening <NUM> aligned with the socket <NUM>. The socket projection <NUM> extends into the opening <NUM>. The opening has projection 139a arranged to engage the lip 117a on the projection <NUM>, to hold the socket in place. A grommet is formed by the outer wall <NUM> to provide a water tight seal between the socket <NUM> and the cover <NUM>, to ensure no water can pass form the exterior of the fitting <NUM>, into the area around the PCB <NUM> and LEDs <NUM>.

The LEDs <NUM> are powered by a current generated by the thermoelectric modules 45a,b. In one example, the current may pass directly to the LEDs <NUM>. Thus the output is dependent on the current provided, which is, in turn dependent on the established temperature difference (i.e. the output is brighter as the temperature difference increases).

In other examples, a controller <NUM> may be provided on the PCB, arranged to control the output of the LEDs. In one example, the controller <NUM> may monitor the voltage or current generated and control the output based on this. In further examples, the LEDs may be controlled based on a switch (not shown) provided on the fitting <NUM>, or a thermistor at the inlets <NUM> or outlets <NUM>.

For example, the controller <NUM> may monitor the stability and/or magnitude of the current or voltage generate.

In one example, when a user desires warm water from the fitting <NUM>, they may turn on the fitting <NUM> and set a desired temperature. To start with, water provided at the hot inlet 9a is cold, due to latency in the system. In this case, the thermostatic cartridge <NUM>, initially only draws water from the hot inlet 9a.

As the water from the hot inlet 9a gradually increases in temperature, the cartridge <NUM> starts to draw both hot and cold water, until the desired temperature is reached at the outlet <NUM>. Furthermore, as the water at the hot inlet 9a gradually increases in temperature, the current/voltage output form the thermoelectric module(s) <NUM> also increases.

In one example, using the above operation, the controller <NUM> may control the LEDs to have three different output modes:.

Therefore, the LEDs <NUM> may be used as an indicator of when the water from the hot inlet 9a is at the correct temperature.

The different modes may include any one or more of: no output (i.e. LEDs off), flashing, varying intensity, varying number of LEDs off, different colour LEDs on/off and the like.

In one example, Modes <NUM> and <NUM> may be the same operational mode, with the output proportional to the magnitude of the generated voltage/current.

In use, the thermoelectric module <NUM> may continue to generate electricity after a user has finished using the ablutionary fitting <NUM>, since there will still be water in the first and second sub-chambers 11a,b and the hot water inlet passage 13a. and there will be a temperature across the thermoelectric module <NUM>. In embodiments, the thermoelectric device may continue to generate electricity for a period of up to or at least <NUM> minutes, up to or at least <NUM> minutes or up to or at least <NUM> minutes after the used has finished using the ablutionary fitting.

In the example discussed above, the generated electricity is used to power LEDs <NUM>. In alternative examples, a portion of the generated electricity may be stored, e.g. in a capacitor or battery, for subsequent use. This may permit for example one or more electrical components and/or devices to operate during start-up of the ablutionary fitting <NUM> after a period of inactivity, when the no temperature difference exists across the thermoelectric module <NUM>. As the water in the hot water inlet passage 13a heats up, the thermoelectric module <NUM> will then generate electricity from the consequent temperature difference.

As discussed above, the heat transfer plate <NUM> and body <NUM> are formed of thermally conductive materials. The housing <NUM> and heat transfer plate <NUM> may be formed of the same material, or different materials. One example of a suitable thermally conductive material is a metal or an alloy, which may comprise, or consist essentially of, copper, aluminium or brass. Alternatively, the heat transfer plate <NUM> and housing <NUM> may comprise, or consist essentially of, a thermally conductive plastic, or a plastic such as an engineering plastic with a thermally conductive material therein and/or thereon. For instance, the thermally conductive material may coat at least partially the plastic. The thermally conductive material may extend through the plastic, e.g. engineering plastic.

The heat transfer plate <NUM> and/or housing <NUM> may be arranged to maximise the temperature differential across the thermoelectric module <NUM>, in order to increase the efficiency of generation of electricity.

For example the projection <NUM> may include fins, or additional surfaces to increase the overall surface area of the heat transfer plate <NUM> in contact with the cold water in the sub-chamber 11b. The surface area in contact with cold water may vary between <NUM> and <NUM><NUM>.

Similarly, the thickness of the housing forming the body <NUM> may optionally be reduced in the region of the thermoelectric module <NUM>. For example, the housing may typically be between <NUM> and <NUM> thick in the region of the module, <NUM>, and may be between <NUM> and <NUM> away from the module <NUM>.

The heat transfer plate <NUM> may be between <NUM> and <NUM> in length and <NUM> and <NUM> in width. The thickness of the heat transfer plate <NUM> may be between <NUM> and <NUM>. On the surface of the heat transfer plate <NUM>, the projection <NUM> may have length between <NUM> and <NUM> and a width between <NUM> and <NUM>. Along the axial direction, the distance between the projection <NUM> and the thermoelectric module <NUM> may be between <NUM> and <NUM> (measured from the closest edges i.e. the rear edge of the projection <NUM> to the forward edge of the module <NUM>.

In the example discussed above, the heat transfer plate <NUM> and thermoelectric module <NUM> are planar, and the curved housing <NUM> includes a wedge projection <NUM> to provide a flat surface to engage both. It will be appreciated that in other examples the heat transfer plate and/or module may either be curved, or have at least a curved surface for engaging the housing <NUM>. Alternatively, the housing <NUM> may have planar surfaces.

The housing <NUM> may be formed of a single unitary part, or may be may of any number of parts joined together. Although in the example discussed above, the housing has a chamber <NUM> split into two sub-chamber 11a,b by seals 33a-c on the cartridge <NUM>, it may be that the chambers 11a,b are formed separately. Likewise, any suitable number of chambers may be formed. For example, there may only be a single chamber for cold water, and the hot water may be provided directly to the cartridge. In this case, the heat is transferred from the hot water inlet passage 13a. Alternatively, three or more chambers may be formed, with two or more chambers optionally carrying water at the same temperature.

In the example shown above, each of the sub-chambers 11a,b extends around the full circumference of the body <NUM>, however, this need necessarily be the case. In other examples, the sub-chambers may only extend around a portion of the circumference of the body <NUM>.

In the example discussed above, a pair of thermoelectric modules <NUM> are provided in the spaces either side of the hot water inlet passage 13a. It will be appreciated that instead of or as well as this, a thermoelectric module <NUM> may be provided directly over the hot inlet passage 13a.

In the example discussed above, a single washer plate <NUM> is provided to thermally isolate the heat transfer plate <NUM> from the housing <NUM>, by thermal conduction through the screws (not shown). It will be appreciated that this function may be provided by separate thermal washers at each screw (not shown).

One example of a socket <NUM> is discussed above. However, it will be appreciated that this is by way of example only. It will be appreciated that any suitable connection may be formed to connect the thermoelectric module(s) <NUM> to the output devices <NUM>. In some examples, the socket <NUM> may be omitted altogether, and the thermoelectric modules <NUM> may be directly connected to the output device(s) <NUM>.

In the example discussed above, a pair of thermoelectric devices 41a,b are coupled to the same socket and output device <NUM>. It will be appreciated that with multiple thermoelectric device <NUM>, this need not be the case, each thermoelectric device <NUM> may have a separate socket and/or output device <NUM>, or two or more thermoelectric devices <NUM> may be connected to the same socket and/or output device <NUM>.

In the example discussed above, heat transfer plate <NUM> is in direct contact with the cold water and the thermoelectric module is thermally coupled to the hot water through the housing <NUM>. However, it will be appreciated that this may be swapped, such that heat transfer plate is in direct contact with the hot water. This may either by swapping which sub-chamber 11a,b receives hot and cold water, or by having the thermoelectric module <NUM> in the region of the cold water chamber 11b, and the projection <NUM> extending into the hot water chamber 11a.

In yet further examples, the housing <NUM> may include sealed openings into both chambers such that the water in the first chamber 11a is thermally coupled to the thermoelectric module <NUM>, with directly or via a second heat transfer plate in direct contact with the hot water.

Claim 1:
An apparatus (<NUM>) for generating an electrical current from a temperature differential in an ablutionary fitting (<NUM>), the apparatus comprising:
a heat transfer plate (<NUM>) having a projection (<NUM>) configured to directly contact water carried in a first region of the fitting (<NUM>); and
a thermoelectric module (<NUM>) comprising one or more thermoelectric elements (97a-c), the thermoelectric elements (97a-c) configured to be thermally coupled between the heat transfer plate (<NUM>) and a housing (<NUM>) of the ablutionary fitting (<NUM>) in a second region of the ablutionary fitting (<NUM>), the thermoelectric elements (97a-c) also being configured to generate electricity from a temperature differential between water carried in the first and second regions of the ablutionary fitting (<NUM>).