EP1810106A1

EP1810106A1 - A thermostatic mixer valve apparatus, a mounting device therefor and a valve cassette

Info

Publication number: EP1810106A1
Application number: EP05796623A
Authority: EP
Inventors: Roderick Joseph Gibbs; Peter James Harold Pegden
Original assignee: Bristan Group Ltd
Current assignee: Bristan Group Ltd
Priority date: 2004-11-03
Filing date: 2005-10-24
Publication date: 2007-07-25
Also published as: WO2006048609A1; GB0424288D0; DE05796623T1

Abstract

A thermostatic mixer valve apparatus comprises a body (10) defining a cold water inlet in fluid communication with a cold water manifold (34) and a hot water inlet in fluid communication with a hot water manifold (30). A first thermostatic mixer valve (22) is arranged in fluid communication with both hot and cold manifolds (30, 34). A second, separate thermostatic mixer valve (22) is arranged in fluid communication with both manifolds. A first mixed water outlet (40) is in fluid communication with the first thermostatic mixer valve (22). A second mixed water outlet (42) is in fluid communication with the second thermostatic mixer valve (27).

Description

A Thermostatic Mixer Valve Apparatus, A Mounting Device Therefor and

A Valve Cassette

The invention relates to a thermostatic mixer valve apparatus, particularly for use in bathroom facilities. It also relates to a mounting device for taps, showers and mixer heads and to a valve cassette.

It is known to provide a thermostatic mixer valve for receiving hot and cold water inlet flows and providing a temperature controlled outlet flow. Such thermostatic mixer valves are generally used to provide water to a bathroom tap or shower head. One such device is shown in US Patent Application No.US2003/0201332. It is known to provide a thermostatic mixer valve which can be switched between flow to a bath tap and flow to a shower head. Such systems allow a choice between bath or shower flows. However, when a user switches between bath and shower flows, it is common for the user to need to adjust the temperature of the flow. Shower flow tends to "feel" hotter than a bath flow of the same temperature as the shower flow contacts the user's skin directly while the bath flow is cooled by the bath walls.

It is an object of the invention to provide an improved thermostatic mixer valve apparatus.

According to a first aspect of the invention there is provided a thermostatic mixer valve apparatus comprising a body defining a cold water inlet in fluid communication with a cold water manifold, a hot water inlet in fluid communication with a hot water manifold, a first thermostatic mixer valve in fluid communication with both of the hot and cold water manifolds, a second, separate thermostatic mixer valve in fluid communication with both of the hot and cold water manifolds, a first mixed water outlet in fluid communication with the first thermostatic mixer valve and a second mixed water outlet in fluid communication with the second thermostatic mixer valve.

In that way individual temperature and flow control of two separate water outlet flows is provided. One flow may be for a bath spout and the other flow may be for a shower head. Alternatively, the flows may be directed to individual shower heads or another outlet format, such as a spray head for cleaning purposes.

Preferably, the mixer valve apparatus is mountable onto a mounting device, the mounting device comprising a body defining a fluid flow path therethrough, the body having a formation to allow mounting of the device to a surface such that one part of the body is arranged on the exterior of the surface and another part is arranged on the interior of the surface, the body having a mounting arrangement on said one part, arranged to mount a tap, shower or mixer valve apparatus thereto, and a valve arranged in the fluid flow path, the valve being actuable between an open position in which fluid can flow therethrough and a closed position in which it cannot, the valve being actuable from the exterior of the surface.

According to a second aspect of the invention, there is provided a water mixer comprising a body having fluid pathways formed therein, the body defining a first water inlet in fluid communication with a first water manifold, a second, separate water inlet in fluid communication with a second, separate water manifold, a first water mixing chamber in fluid communication with both first and second manifolds, said first water mixing chamber having a first, mixed-water outlet, and a second, separate water mixing chamber in fluid communication with both first and second manifolds, said second water mixing chamber having a second, separate mixed-water outlet.

Preferably the mixing chambers receive respective thermostatic mixer valves so as to effect thermostatic mixing of the first and second water streams.

According to a third aspect of the invention, there is provided a mounting device for a tap, shower or mixer valve, the device comprising a body defining a fluid flow path therethrough, the body having a formation to allow mounting of the device to a surface such that one part of the body is arranged on the exterior of the surface and another part is arranged on the interior of the surface, the body having a mounting arrangement on said one part, arranged to mount a tap, shower or mixer valve apparatus thereto, and an isolator valve arranged in the fluid flow path, the isolator valve being actuable between an open position in which fluid can flow therethrough and a closed position in which it cannot, the isolator valve being actuable from the exterior of the surface.

The isolator valve is preferably located in the fluid flow path in said one part of the body. Alternatively, if the isolator valve is located in said other part of the body, there is provided a valve actuation member which extends from said other part to said one part to allow actuation of the isolator valve from the exterior of the surface.

Preferably, where the isolator valve is located in said one part of the body, the body is provided with an opening to allow actuation of the isolator valve. In such a case, the mounting device may be mountable in rotatable fashion to allow the opening to be rotated into a more readily accessible position when the need arises and to rotate the opening into a more concealed position in normal use.

The terms "exterior" and "interior" relate to the surface to which the device is mounted. Thus, where the surface is a sink, the exterior is the part above the surface of the sink and the interior is beneath the surface of the sink. Likewise, where the surface is a bath, "exterior" is above the bath surface and "interior" is beneath it. Furthermore, where the surface is a shower wall, the "exterior" is the part exposed to the user in front of the wall whilst the "interior" is the part behind the wall.

In that way, fluid supply to the tap, shower or mixer can be cut off to enable removal of the tap, shower or mixer, for example, for repair or replacement, without requiring access to the "interior" of the surface. This means, for example, that the water supply can be isolated without having to remove a bath fascia panel to access the area beneath the bath.

Where a tap, shower or mixer is mounted to the mounting device, the tap, shower or mixer head preferably defines a fluid flow path and has a valve cassette removably received in the flow path downstream of the valve in the mounting device, the cassette having a check valve, a fluid filter and a flow limiter. According to a fourth aspect of the invention, there is provided a valve cassette comprising a cassette body receiving a check valve, and a flow limiter and defining a flow path therethrough.

In a fifth aspect there is provided a tap, shower or mixer head comprising a body defining a fluid flow path, the path defining a valve cassette receiving recess arranged to receive a valve cassette as described immediately above.

hi a sixth aspect there is provided a tap, shower or mixer head comprising a body defining a fluid flow path, a valve cassette removably received in the path, the valve cassette having a check valve, a fluid filter and a flow limiter.

A thermostatic mixer valve apparatus, a mounting device for such an apparatus and a valve cassette for use in such an apparatus will now be described in detail by way of example and with reference to the accompanying drawings, in which:-

Fig.l is a cross-sectional view through a thermostatic mixer valve apparatus in accordance with the first aspect of the invention,

Fig. Ia is a cross-sectional view through the apparatus of Fig.1 with the valves removed, Fig.2 is a cross-sectional view through part of the apparatus of Fig.1 shown to a larger scale,

Fig.3 is a cross-sectional view through another part of the apparatus again shown to a larger scale,

Fig.4 is a cross-section through the apparatus of Fig.1 taken on line FV-IV in Fig.l, Fig.5 is a plan view of the apparatus of Figs.1-4 looking in the direction of arrow V in

Fig.4 and showing part of the apparatus in section,

Fig.6 is a cross-sectional view through the thermostatic mixer valve of Figs.1 to 3, Fig.7 is a cross-section through a mounting device for the thermostatic mixer valve apparatus of Figs.1-5, including a check valve cassette. In Fig.l a thermostatic mixer valve apparatus comprises a body 10 for mounting to a surface, such as a sink, bath or shower wall. The surface is generally indicated at S.

The body 10 defines hot and cold water inlets, a series of internal passageways and bath and shower outlets. The body 10 is substantially H-shaped when viewed in Fig.l . A body 10 comprises a first upstanding part 12, a second upstanding part 14 and an interconnecting part 16 connecting the first and second upstanding parts together.

The first upstanding part 12 is mounted on a mounting device 18 which will be described in greater detail later. The upstanding part 12 further includes a valve cassette 20 which will also be described in greater detail later arranged in a fluid passageway in the upstanding part 12. A thermostatic mixer valve 22 is arranged in an upper part of the upstanding portion 12 and is arranged to feed mixed water M to a spout for a bath. The second upright part 14 is also mounted on a mounting device 18 and receives a check valve cassette 20 thereon. Still further, a thermostatic mixer valve is received in an upper part of the second upright part that is arranged to feed mixed water M to a shower outlet (not shown).

The body 10 is shown in detail in Fig. Ia with the various valves and mounting devices removed. In Fig. Ia it can be seen that the upstanding portion 12 includes a stepped bore 24 having a first portion 24A and second portion 24B having a smaller diameter than the first portion 24A. A small radial bore 26 is formed through the wall of the first upright portion 12 so that it extends between the outer surface of the upright portion 12 and the first portion 24A of the stepped bore 24. A shoulder 25 is formed between the first and second portions of the stepped bore 24A, B. The second portion 24B terminates in a shoulder 27 formed by a small annular projection. The bore then opens out into a chamber 28 which, in turn, communicates with a manifold 30 formed in the interconnnecting piece 16 and extending from the first upright portion 12 to the second upright portion 14. The second upright portion 14 also has a stepped bore 24 which is substantially identical to that of the first upright portion 12. A radial bore 26 is also formed extending from the first portion of the bore 24A to the outer surface of the upright portion 14. Like the bore formed in the first upright portion 12, the bore 24 narrows via shoulder 25 from a first bore portion 24A to a second bore portion 24B having a smaller diameter and which terminates in a shoulder formed by a smaller annular projection 27. In the first upright portion 14, the bore opens into a chamber 32 which, in turn, communicates with a manifold 34 formed in the interconnecting portion 16 and extending from second upright portion 14 to the first upright portion 12. The bore 24 in the first upright portion 12 defines a hot water inlet whilst the bore 24 in the second upright portion defines a cold water inlet.

The first and second upright portions define respective cavities for receiving respective thermostatic mixer valves. The cavities 36, 38 are in fluid communication with the hot and cold manifold 30, 34. The cavity 36 in the first upright portion 12 is arranged in fluid communication with a fluid outlet 40 which feeds a bath tap. The cavity 38 is in fluid communication with a fluid outlet 42 which feeds a shower fitting. The outlets 40, 42 are formed in the interconnecting portion 16 of the body 10. The outlets 40, 42 are illustrated in more detail in Figs.4 and 5.

The thermostatic mixer valves 22 which are received in the cavities 36, 38 in the first and second upright portions 12, 14 are of known design and function to receive hot and cold water from the manifolds 30, 34 respectively and to allow mixing of that water before it flows to the respective outlet 40, 42. A detailed description of the operation of the thermostatic mixer valve is set out below.

In Fig.6, the mixer valve 22 is shown to a larger scale. The valve 22 comprises a flow control part 80 and a temperature control part 82.

The flow control part 80 comprises an annular valve seat 84 and a valve body 86 movable relative to the valve seat 84.

The valve seat 84 is received in a valve seat bore 88 in the thermostatic mixer valve apparatus body 10. A sealing ring 90 is arranged in an annular groove 92 formed around the outer periphery of the valve seat 84 to seal the valve seat 84 against the wall of the bore 88. That prevents passage of water between the valve seat and the wall of the bore 88. The valve seat 84 is substantially cylindrical and defines a space to receive part of the temperature control part 82.

The valve body 86 comprises a series of stepped cylindrical parts 94a, 94b and 94c of progressively increasing diameter with a bore 96 formed therethrough. The uppermost cylindrical part 94a, having the smallest diameter, has a screw-threaded outer surface 98. The middle cylindrical part 94b includes an annular groove 100 formed around its outer periphery which receives a sealing O-ring 102. The lowermost, and widest, cylindrical part 94c has an end face 104 in which an annular groove 106 is formed. A sealing O-ring 108 is received in the annular groove 106.

The bore 96 comprises a first diameter part 96a, a second greater diameter part 96b and a third still greater diameter part 96c. The middle part 96b of the bore 96 is internally screw-threaded at 110.

The valve body 86 is received in a valve head 112. The valve head 112 comprises a hollow cylindrical body 114, open both ends. At the upper end of the body 114, there is a stepped-in cylindrical part 116. The valve head 112 is itself received in a bore 118 of the mixer valve apparatus body 10. A turning 120 is received in the valve head 112 by means of a circlip (not shown). The turning 120 comprises a substantially cylindrical body 122 with a bore 124 formed therethrough, the bore 124 having a screw-thread 126.

The internal screw thread 126 of the bore 124 is arranged to co-operate with the external screw thread 98 of the cylindrical part 94a of the valve body 86. The turning 120 is restrained by means of the circlip (not shown) and the stepped-in cylindrical portion 116 of the valve head 112. The valve body 86 is restrained from rotational movement by means of guiding vanes 128 carried by the valve head 112 co-operating with slots (not shown) on the outer peripheral surface of the cylindrical part 94c. In that way, rotational movement of the turning 120 is converted into axial transitional movement by the co-operation between the screw threads 98, 126 and the guide vanes 128. Thus, the valve body 86 can be arranged to move towards and away from the valve seat 84. In order to close the valve and prevent flow of water therethrough, the turning 120 is rotated until the O-ring 108 sealingly engages the valve seat 84. Rotation of the turning in the opposite direction moves the valve body 86 away from the valve seat 84, allowing water to flow through the gap between the O-ring 108 and the valve seat 84.

The temperature control part 82 comprises a distributor 130, a thermostat 132, a return spring 134 and a maximum temperature control mechanism 136. The distributor 130 is mounted within the space defined by the valve seat 84.

Distributor 130 comprises an annular body 138 having a frustoconical part 144 and a cylindrical part 145. Eight upstanding fingers 146 extend away from the frustoconical part 144 and the fingers 146 include respective formations 147 at their upper ends arranged to define a mounting for the thermostat 132. Four downwardly depending legs 148 extend from the cylindrical part 145 of the distributor 130 and the legs 148 are connected to a hat-shaped member 150. A piston 140 is carried by the brim part of the hat-shaped member 150. The piston 140 comprises a cylindrical side wall 152 with an annular inwardly projecting part 154. An over travel spring 142 extends between the cylindrical part 145 of the distributor 130 and the annular inwardly projecting part 154 on the piston 140.

The thermostat 132 comprises a base part 132a which sits on the formations 147 of the fingers 146 and an upstanding cylindrical part 132b which extends upwardly towards the maximum temperature control mechanism 136.

The maximum temperature control mechanism 136 comprises a body 156 which is arranged in the bore 96 in the valve body 86. The body 156 has an annular recess with an O-ring received therein to seal the body 156 against the bore 96. The lower part of the body 156 includes a screw thread 158 on its outer surface which inter-engages with the screw thread 110 in the middle part 96b of the bore 96.

A circular recess 159 is formed in the wall between the hot and cold manifolds 30, 34 and the recess receives an O-ring 160 to seal against the outer cylindrical wall 152 of the piston 140 to prevent fluid flow between the two manifolds. A recess 162 is formed in the body 10 beneath the temperature control part 82 to receive the return spring 134.

An annular recess 164 is formed around the recess 162 and that receives an O-ring 166.

A hexagonal cross-section bore is formed in the upper part of the body 156 of the maximum temperature control mechanism 136.

It will be noted that the length of the cylindrical side wall 152 of the piston 140 is shorter than the distance between the O-ring 164 and the underside of valve seat 84. It can be seen, therefore, that the piston 140 can selectively fully close off either the cold water manifold or the hot water manifold but not both. Furthermore, it is possible for the piston to attain a position whereby both cold and hot water manifolds are open. The position of the piston 140 is determined by the expansion of the thermostat 132. hi use, when the valve body 86 moves away from the valve seat 84 allowing water to flow through the gap between the O-ring 108 and the valve seat 84, the thermostat 132 is exposed to the water flow, hi the position illustrated in Fig.6, the piston 140 has a starting position which closes off the cold water manifold altogether. Consequently, hot water flows through the gap between the piston 140 and the O-ring 164, up through the distributor 130, via the base 132a of the thermostat 132, through the gaps between fingers 146 and out through the gap between O-ring 108 and valve seat 84. The hot water tends to cause the thermostat 132 to expand. Consequently, the upstanding part 132b of the thermostat 132 expands until it contacts the underside of the maximum temperature control mechanism 136. Further expansion of the thermostat thus causes the distributor 130 to be pushed downwardly against the action of the return spring 134. That, in turn pushes the piston 140 downwardly moving the upper part of the piston 140 away from the underside of the valve seat 84. That allows cold water to flow between the piston 140 and the valve seat 84 from the cold water manifold 34. Hot and cold water are thus allowed to flow up through the distributor 130 where they are mixed and allowed out of the valve via the gap between O-ring 108 and valve seat 84 as illustrated by the mixed water flow M in Fig.6. hi the event that too much cold water is allowed through, the thermostat 132 will contract, which in turn causes the distributor 130 to be pushed upwardly under the action of the return spring 134. That, in turn, reduces the width of the gap between the upper part of the piston 140 and the valve seat 84 and increases the size of the gap between the lower part of the piston 140 and the O-ring 164. Thus the balance of hot and cold flow is redressed allowing the desired temperature to be attained. In order to alter the temperature of the water flow, the turning 120 is rotated which causes the valve body 86 to move relative to the valve seat 84. That changes the distance between the underside of the maximum temperature control mechanism 136 and the upper most part of the thermostat 132, allowing for greater or lesser expansion of the thermostat before acting on the distributor 130. By moving the valve body 86 downwardly as shown in Fig.6, the gap between the maximum temperature control mechanism 136 and the thermostat is reduced. Thus the thermostat does not need to expand a great deal before it acts to push the distributor 130 downwardly allowing increased cold water flow. Accordingly, in that event the temperature of the mixed water flow would be reduced. By moving the turning 130 so that the valve body 86 moves away from the valve seat 84, the distance between the underside of the maximum temperature control mechanism 136 and the thermostat 132 is increased allowing increased expansion of the thermostat before the thermostat acts to move the distributor 130. That would tend to increase the temperature of the mixed water.

The position of the maximum temperature control mechanism 136 within the valve body 86 determines the maximum possible water temperature produced by the valve. By rotating the body 156 of the maximum temperature control mechanism 136 by means of a hexagonal tool in the recess 168, the position of the body 156 can be altered as the body 136 is screwed inwardly and outwardly by virtue of the co-operation between the screw thread 110 and screw thread 158. The position of the maximum temperature control mechanism 136 is set prior to installation of the valve and is not readily adjustable by the user.

The over travel spring 142 prevents the system from being damaged in the event that the thermostat pushes the distributor 130 down beyond the point where the piston 140 contacts the O-ring 164. The over travel spring 142 is stiffer than the return spring 134 so that the return spring 134 is deflected before deflection of the over travel spring 142. One example of where that might be needed is in the event of a failure of the cold water supply. In such an event, the hot water flowing past the thermostat will cause the thermostat to expand, forcing the distributor 130 downwardly until the piston 140 contacted the O-ring 164. However, the thermostat would still be in contact with the hot water which had already passed the piston 140 and that may cause continued expansion of the thermostat 132 after contacting the piston 140 with the O-ring 164. Continued expansion of the thermostat will be taken up by compression of the over travel spring 142.

Turning to Fig.7, a mounting device in accordance with the second aspect of the invention is shown. The mounting device 18 comprises a cylindrical body 44 cruciform-shaped, in section. The body 44 comprises first cylindrical portion 46 having a screw-threaded outer surface 48 and a bore 50 formed therethrough. At its lower end, the bore 50 has an enlarged diameter portion 52 so as to form a shoulder 54. The body 44 further comprises an enlarged diameter disc-like portion 56. The bore 50 continues through the enlarged diameter portion 56. The bore 50 is stepped down by means of an annular projection 58 and then steps outwardly via two shoulder portions 60, 62. A radial passageway 64 is formed from an outer edge of the enlarged disc portion 56 to the bore 50. The body 44 further comprises a cylindrical axial projection 66 which projects from the side of the enlarged disc-like portion 56 opposite from the cylinder 46. The outer surface of the cylindrical projection 66 includes an annular recess 68. The bore 50 continues through the cylindrical projection 66.

An isolator valve 70 is received in the bore 50 in the enlarged disc-like part 56 of the body 44. The isolator valve 70 is actuable between an open condition in which fluid can pass through the bore 50 and a closed condition in which fluid is prevented from passing through the bore 50 by the valve 70. The valve 70 is actuable by manipulating the valve 70 with an appropriate tool, for example an Allen key via the radial passageway 64.

The check valve cassette 20 is also illustrated in Fig.7. The check valve cassette 20 comprises a cylindrical body 170. The body 170 has annular recesses 172, 174 formed in the outer surface thereof adjacent opposite ends thereof. 0-rings 176, 178 are received in the recesses 172, 174. A bore 180 is formed through the body 170 coaxially therewith, from one end 181a to opposite end 181b. The bore 180 comprises a first diameter portion 180a, a second diameter portion 180b and a third diameter portion 180c. The first diameter portion 180a of the bore extends from one end of the body, substantially the length of the body, terminating short of the opposite end 181b in a shoulder 182. The shoulder 182 defines the start of second diameter portion 180b which has a smaller diameter than first diameter portion 180a. Second diameter portion 180b then widens out into third diameter portion 180c via shoulder 184. The third diameter portion 180c extends from shoulder 184 to the opposite end 181b. The third diameter is greater than the second but smaller than the first.

The first diameter portion 180a of the bore 180 receives a check valve 186 of known construction. The check valve abuts the shoulder 182 and an O-ring arranged around the outer periphery of the check valve seals against the inner surface of the body 170 which defines the bore 180. A flow limiter 188 of known construction is received in the second and third diameter portions 180b, of the bore 180.

The check valve cassette 20 is advantageous as it allows separate subassembly of the check valve and flow limiter. That makes installation of the apparatus more straightforward as the flow limiter and check valve do not need to be carried individually and they can be installed or removed in one operation.

In order to install the thermostatic mixer valve apparatus on, for example, a bath panel, the plumbing for the hot and cold water supplies is arranged beneath the panel S. Holes are formed through the panel S at an appropriate spacing and the mounting devices 18 are arranged on the bath panel S with the cylindrical portion 46 of the body 44 extending through the respective holes. The bottom part of the enlarged disc-like portion 56 of the body 54 rests on the bath panel S and the isolator valve 70 is turned to the closed position. A filter 190 is inserted into the cylindrical part 66 of the body 44 and the check valve cassette 20 is inserted on top of the filter. The hot and cold water outlets are connected to the respective screw-threaded parts 48 of the cylinder 46 of the mounting device 18 in a watertight and conventional manner. The thermostatic mixer valve apparatus is then arranged on top of the respective mounting devices 18 so that the check valves 20 are received in the bores 24B and the cylindrical projections 66 of the mounting devices 18 are received in the bores 24A. Grub screws are then inserted along screw-threaded passageways 26 so that the tips of the grub screws engage in the annular recesses 68 of the cylindrical projection 66, thus securing the body 10 of the mixer apparatus to the mounting device 18.

In the event that the user wishes to service the valve, isolator 70 is accessed through passageway 64 turning off the supplies to the device. The grub screw in the passageway 26 can be removed and the complete mixer apparatus can be removed for servicing. It can be seen that being able to isolate the supply and remove the device from above the bath panel S without having to remove the bath panel or gain access behind it is a considerable time saving, As described the mounting device 18 can be rotated so that it can be mounted in any orientation so that passage ways 64 and 26 can be positioned to the best aesthetic advantage.

The present invention provides an advantageous thermostatic mixer valve apparatus which provides individual temperature control of two alternative water flows whilst utilising only a single hot water supply and cold water supply. The mounting device allows isolation of the mixer valve apparatus without the requirement for access behind the surface on which it is mounted representing a considerable saving in labour time for repair, maintenance or replacement of the mixer valve apparatus. The check valve cassette accommodates two components in one unit which allows for ready removal and replacement of those components when required.

Claims

1. A thermostatic mixer valve apparatus comprising a body defining a cold water inlet in fluid communication with a cold water manifold, a hot water inlet in fluid communication with a hot water manifold, a first thermostatic mixer valve in fluid communication with both of the hot and cold water manifolds, a second, separate thermostatic mixer valve in fluid communication with both of the hot and cold water manifolds, a first mixed water outlet in fluid communication with the first thermostatic mixer valve and a second mixed water outlet in fluid communication with the second thermostatic mixer valve.

2. A mounting device for a tap, shower or mixer valve, the device comprising a body defining a fluid flow path therethrough, the body having a formation to allow mounting of the device to a surface such that one part of the body is arranged on the exterior of the surface and another part is arranged on the interior of the surface, the body having a mounting arrangement on said one part, arranged to mount a tap, shower or mixer valve apparatus thereto, and an isolator valve arranged in the fluid flow path, the isolator valve being actuable between an open position in which fluid can flow therethrough and a closed position in which it cannot, the isolator valve being actuable from the exterior of the surface.

3. A mounting device according to claim 2 in which the isolator valve is located in the fluid flow path in said one part of the body.

4. A mounting device according to claim 2 in which the isolator valve is located in said other part of the body and there is provided a valve actuation member which extends from said other part to said one part to allow actuation of the isolator valve from the exterior of the surface.

5. A mounting device according to claim 3 in which the body is provided with an opening to allow actuation of the isolator valve.

6. A mounting device according to claim 5 in which the mounting device is mountable in any orientation to give either a more accessible position or a more aesthetically pleasing appearance or it is mountable in rotatable fashion to allow the opening to be rotated into a more readily accessible position when the need arises and to rotate the opening into a more concealed position in normal use.

7. A mounting device according to any of claims 2 to 6 in which a tap, shower or mixer is mounted to the mounting device, the tap, shower or mixer head defining a fluid flow path and a valve cassette is removably received in the flow path downstream of the valve in the mounting device, the cassette having a check valve and a flow limiter.

8. A thermostatic mixer valve apparatus according to claim 1 and mountable onto a mounting device according to any of claims 2 to 7.

9. A valve cassette comprising a cassette body receiving a check valve, and a flow limiter and defining a flow path therethrough.

10. A tap, shower or mixer head comprising a body defining a fluid flow path, the path defining a valve cassette receiving recess arranged to receive a valve cassette according to claim 9.

11. A tap, shower or mixer head comprising a body defining a fluid flow path, a valve cassette removably received in the path according to claim 9.

12. A water mixer comprising a body having fluid pathways formed therein, the body defining a first water inlet in fluid communication with a first water manifold, a second, separate water inlet in fluid communication with a second, separate water manifold, a first water mixing chamber in fluid communication with both first and second manifolds, said first water mixing chamber having a first, mixed-water outlet, and a second, separate water mixing chamber in fluid communication with both first and second manifolds, said second water mixing chamber having a second, separate mixed-water outlet.

13. A water mixer according to claim 12, in which each mixing chamber receives a thermostatic mixer valve.