IE911970A1 - Thermostatic mixer for water supply installations - Google Patents

Abstract

A thermostatic mixer has a cartridge unit is detachably mounted in mixer body 17 and arranged to permit assembly of the cartridge unit 15 in either one of two selected positions dependent on the connections to the hot and cold water supplies. To this end, the cartridge unit is provided with two outlets 186, 187, only one of which communicates with a single outlet 44 in the mixer body 17, the other outlet being blocked by a flange 43 in the body 17. The cartridge unit 15 houses a shuttle valve 165 for controlling the relative proportions of hot and cold water admitted to a mixing chamber 178 and a thermostat 156 responsive to the mixed water temperature is operable to adjust the shuttle valve 165 to maintain constant the mixed water temperature selected by actuation of a temperature control knob 7. The flow rate is selected by actuation of a flow control knob 12 which controls respective valve assemblies (70, 71) (Fig. 5 not shown) for the hot and cold water supplies. The knobs 7, 12 are both detachably mounted on the cartridge body 15.

Description

This invention relates to a thermostatic mixer for water supply installations, particularly but not exclusively, for mixing het and cold water for ablutionary showers for domestic insta11 at ions.

The installation of ablutionary showers is becoming more popular, and one of the common problems to be faced by an installer is local variations in water quality as well as water pressure from the mains or other supply in a water circuit.

Particular problems arise in hard water areas where lime and scale deposits can build up and interfere with proper performance of valves. Special maintenance and servici'ng is often required including stripping down the assembly and replacing seals and other parts. This servicing requires specialist knowledge and may be costly to a domestic user in a very hard water area.

Another problem to be faced by an installer is the existing plumbing pipes and the wide variety of orientations and connections for hot and cold supplies and the outlet. In many situations it is desirabie not to disturb existing plumbing carcassing. In addition, in some locations it is desirable to minimise installation and fitting damage to existing surface or decorative finishes by changing existing runs of water supply pipes. With many known mixing'va1 Yes, a range of types to suit installer requirements for rear, or exposed top or bottom supply, right or left side cold supply and top or bottom outlet has had to be provided by a manufacturer and stocked by a distributor or retailer.

Furthermore, there is a demand for high rates of flow for showers, and certain existing designs of thermostatic mixing valves produce a significant decrease in flow rate due to the pressure loss derived from the flow control valve arrangement.

It is an object of this invention to provide an improved thermostatic mixer having a special construction to ensure a long maintenance-free period.

It is an object of this invention to provide an improved thermostatic mixer that can be installed in a very simple manner for a wide range of installer requirements.

It is a further object of this invention to provide an 05 improved thermostatic mixer which can be serviced in a simple manner not requiring specialist skills.

It is yet another object of this invention to provide a thermostatic mixer having high performance characteristics for a given water pressure and which is adaptable to suit certain water pressures and desired flow rates.

Other objectives of this invention will be explained and referred to later herein with reference to an exemplary embodiment of the invention.

According to this invention we provide a thermostatic mixer comprising a body having hot and cold water inlets for connection respectively to hot and cold water supplies and having a mixed water outlet, a cartridge unit having a sealed housing with a porting member having opposed hot and cold inlet ports and opposed outlet ports, the porting member being received in a seating in the body with the hot and cold inlet ports and one outlet port in communication with the respective inlets and outlet of the body, the cartridge housing mounting respective flow control valve assemblies for actuation to control flow of hot and cold water through respective passageways leading to a shuttle valve mounted for axial movement between hot and cold seats to vary the relative proportions of hot and cold water admitted to a mixing chamber in communication with one of the two outlet ports, a thermostat responsive to temperature of water in the mixing chamber to control movement of the shuttle valve in accordance with adjustable selection of the mixed water temperature, and the cartridge unit having retention means for detachably retaining on the unit a flow control member arranged to actuate the flow control valve assemblies and for detachably retaining a temperature control member arranged to control thermostatic response of the shuttle valve, and both the cartridge unit and the mixer body having mounting means arranged for releasably securing the cartridge unit to the mixer body in one of two opposed positions and in each position only one of the outlet ports of the unit is in communication with the body outlet whereby the cartridge unit can be dismounted from the mixer body or can be located and secured to the mixer body in one of two selected positions dependent on the connections to hot and cold I (J water supplies.

The invented thermostatic mixer provides a mixer body and a sealed cartridge unit which can be located in the mixer body to suit the orientation of water supply connections and the outlet to an appliance. This provides simple versatility for the installer.

Furthermore, the use of a sealed cartridge housing enclosing all operative valves and the thermostat provides a thermostatic mixer in which specialist servicing is avoided and if any malfunction arises, the defective cartridge can be replaced in a very simple manner, for example by a non-ski lied person such as a DIY enthusiast.

The cartridge unit is designed to be a factory sealed unit for long maintenance-free service in normal use.

Preferably, each flow control valve assembly comprises a 25 sliding plate valve and both flow control valves are actuated by a common member arranged to be operated by the flow control member retained on the cartridge housing.

By this preferred construction, the hot and cold inlet ports of the cartridge unit are opened or closed simultaneously by operation of the flow control member. Accordingly, when the flow control member is in the closed position both the hot and cold inlet ports are closed and the cartridge unit is isolated from the hot and cold water supply connections. This facilitates the - 5 fitting and/or replacement of the cartridge unit and the mixer assembly.

By providing a sliding plate valve, the buiid up of scale or other deposits from the water is obviated due to the self-cleaning action on the relative sliding movement of the valve plates on actuation of the valve.

According to another preferred feature, the sliding plate valves each comprise ceramic elements.

The use of ceramic elements in the sliding plate valve 10 assembly further obviates corrosive attack or other adverse effects arising from the presence of certain compounds in the water.

Preferably each sliding plate valve assembly is similar and comprises inner and outer fixed ceramic elements with a slidable ceramic valve element extending therebetween mounted for actuation by a yoke operably connected to the flow control membe r.

Conveniently, each of the ceramic elements is formed with a throughway and the throughway of the sliding element is aligned with the throughways of the fixed elements in the open position and in the closed position is out of register to close the associated inlet and the passageway leading to the shuttle valve.

By such an arrangement flow rates can be optimised as pressure loss through the valve plates can be minimised by the designed size and shape of the throughways.

Other design features of the sliding plate valve assembly including the special form of the throughways will be described later herein.

The cartridge housing may be of a strong plastics material 30 and may be a welded or bonded assembly of mouldings defining the internal mixing chamber within which the thermostat and shuttle valve are supported and arranged for co-axial movement. - 6 The use of plastics material of suitable type and grade for mouldings that are welded or bonded together provides advantages in resistance to adverse water effects and reduces heat losses by thermal conductivity as compared to the traditional use of common Ob metal, such as brass, for such parts of a mixing valve.

The retention means provided on the cartridge unit for locating and supporting the temperature control member are preferably arranged so that the temperature control member, such as a manually rotatable knob, can be removed or fitted as may be 1U required on installation or replacement of the cartridge unit.

Conveniently such retention means may comprise resilient limbs on the temperature control member arranged to engage with formations on a hub with a snap-on11 or snap-off action.

Similarly, the retention means provided on the cartridge unit for locating the flow control member may also comprise resilient limbs arranged to engage with formations in the flow control member, such as a rotatable knob, so that the flow control member can be engaged and disengaged in a simple snapact i on.

The invented mixer may also comprise trim members or shrouds which also fit on or over the cartridge unit or the mixer body to enclose the cartridge unit and the mixer body. Preferably, such trim or shroud members are also readily detachable or fitted.

The cartridge housing includes a porting member which is assembled and bonded to a closure member. The porting member provides the passageways respectively for hot and cold water and defines a cold seating engageable by the cold seat of the shuttle valve. The porting member further provides a mounting for an adjustable hot seating for engagement with the hot seat of the shuttle valve.

Conveniently, the cold seating and the hot seating are opposed to each other and are of annular form with the shuttle valve being co-axially arranged for axial movement in response - 7 the changes in the thermostatic response of the thermostat between the respective hot and cold seatings.

Accordingly, in the cartridge unit, the relatively movable parts of the shuttle valve and the thermostat are co-axially arranged and a compact and flow efficient arrangement is achieved to reduce pressure losses that can arise when water passageways are relatively long and convoluted.

The hot seating is comprised in a mounting supported in the cartridge porting member and arranged for relative adjusting movement to vary the position of the hot seating as may be required for the axial movement of the shuttle valve controlled by the thermostat.

Preferably, the hot seating comprises an annular seating member of a thermoplastics elastomeric material.

These preferred arrangements ensure that accurate adjustment of the hot flow can be made, and by providing an elastomeric material for the hot seating, when engaged by the hot seat of the shuttle valve, then any build up of debris or scale is displaced due to resilient flexibility of the hot seating member.

Conveniently, the adjustment of the hot seat mounting may be arranged so that an index reference is visible on the outside of the cartridge unit from which the degree of adjustment may be noted by the fitter, installer. This provides advantages when replacing or installing the cartridge unit.

The thermostat comprises an elongate hollow body filled with a thermally responsive wax that acts on an actuator rod projecting axially from one end of the thermostat and which extends or retracts relative to the body in response to changes in volume of the wax on change of temperature of water in the mixing chamber in which the body extends. The other end of the thermostat body is seated in a support member for the shuttle valve arranged co-axial ly with the thermostat body. - 6 Co-axial spring means acts between the thermostat body and the shuttle valve to maintain the shuttle valve in support engagement with the support member. The end of the actuator rod of the thermostat is received within a recess in a drive nut which is arranged for adjustable axial movement through the temperature control member to control the responsive movement of the shuttle valve between the hot and cold seatings on thermoresponsive changes of the thermostat to the temperature of water in the mixing chamber.

Such an arrangement ensures that the shuttle valve acts directly to vary the respective hot and cold water flows into the mixing chamber from the respective hot and cold passageways and time lag effects are minismised due to the direct coupling of the shuttle valve to the thermostat.

Preferably, the thermostat is also acted on by return spring means acting in opposition to the co-axial spring means acting between the thermostat and the shuttle valve. Such return spring is conveniently seated within a recess provided in the hot seat mounting and also acts as a safety overload spring for the thermostat.

Various other features and technical advantages arising from the special construction and arrangement of the invented mixer will be described later herein with reference to an embodiment of the invented mixer.

An exemplary embodiment of the invented mixer will now be described with reference to the accompanying drawings wherein:FIGURE 1 is a front elevation of the mixer as assembled and installed for a back inlet connection to respective hot and cold water supply pipes; FIGURE 2 is an underneath plan view in the direction of arrow A shown in Figure 1; FIGURE 3 is a side view with a partial scrap section on line B-B of Figure 2 and with other parts omitted for clarity; FIGURE *4 is a perspective view of the mixer of Figure certain parts being omitted or broken away to reveal arrangements in schematic form; FIGURE 5 is a sectional view on line C-C of Figure 3 assembled mixer omitting supply pipe connections and flow control valves open and the proportioning valve posi tion; with the internal of the showing the in a mi cFIGURE 6 is a sectional view on line D-D of Figure 5; FIGURE 7 is a sectional view similar to Figure 5 depicting only the cartridge; FIGURE 8 is a side view of the cartridge in the d i rect ion of arrow E of Figure 7; FIGURE 9 is a plan view of the cartr i dge i n the d i rect i on of arrow F shown in Figures 7 and 8; FIGURE 10 is a schematic view of parts of the flow control valve; FIGURE 11 is a detail side view, partly sectioned, of the mixer body; and FIGURE 12 is a plan view of the mixer body taken in the direction of arrow G shown in Figure 11.

The exemplary embodiment will be described first in general terms in relation to the principal arrangements and construction.

With reference to Figures 1, 2 and 3, the exemplary embodiment of the invented mixer 1 is designed for mounting to a wall or partition 2 and for connection to respective hot and cold water supply pipes 3,^. Other arrangements for mounting and water supply connections may be applied to the basic concept of the invented mixer and will be referred to later herein.

The invented mixer is intended to discharge temperature controlled mixed or blended water through an outlet 5 to which is connected by a hose 6, in known manner, a shower head or spray handset or other ablutionary appliance. Details of such appliances are not depicted or described herein. - 10 The mixer 1 has a temperature control knob 7 having an upstanding cross grip 8, and the temperature knob 7 is arranged for limited rotation of about 180° for a range of ablutionary temperatures, for example from cold to 65°C . The temperature knob 7 includes an indicia 3 for indicating the selected temperature against an annular temperature indicator trim 10 having a range of register scale marks spaced between opposite block markers 11 for full hot and cold extremes.

The mixer 1 has a flow control knob 12 mounted concentric with the temperature knob 7· The flow knob 12 is arranged for rotation to control and regulate the flow of water into the mixer from off to fully open. The flow knob 12 has finger grip recesses 13 to facilitate gripping.

A waisted shroud trim 14 covers part of the internal cartridge unit 15 (to be described later). Another generally cylindrical body shroud 16 encloses the mixer body 17 (to be described later). The body shroud 16 has opposed clearance cutouts 18 (see Figure 4) and an opening 19 through which the outlet 5 extends.

A mounting backplate 20 for fixing the mixer to the wall 2 is of waisted cylindrical shape and has an outer rim flange 21 contiguous with the external cylindrical face of the body shroud 16. The mixer body 17 is supported and secured to the backplate 20.

The hot and cold supply pipes 3,A are connected by respective gland unions 22,23 and at each union connection there is a respective one of two similar bezel trims 24,25 arranged to abut the wall 2 to cover the adjacent surface.

In this embodiment of the mixer, the mixer is shown for the back inlet connection with a bottom outlet for the mixed water.

With reference also to Figures 4 and 5, each of the gland unions 22,23 is connected to one of two similar inlet elbow members 26,27 that are adjustably fitted to respective bored - η inlet bosses 28,29 and secured thereto by resDective grub screws 30.31. Cover caps 32,33 are seated over the respective heads of the screws 30,31.

The mixer cartridge unit 15 as shown clearly in Figure 8 is 05 adapted and arranged for support and securing in the mixer body 17 as depicted in detail in Figures 11 and 12.

The mixer body 17 is metal, preferably brass, and has the bored opposed inlet bosses 28,29 providing hot and cold inlets 3A,35 opening through opposed side walls 36,37 of a generally rectangular recess 38 in which one part referred to as the porting member 39 of the cartridge unit 15 is received and located. The other opposed longer side walls ΑΟ,Αΐ are shaped to complement the external profile of the porting member 39The body 17 has opposed front flanges A2,A3 having co-pianar flat faces. An outlet opening AA extends through the flange A2 leading to an internally threaded transverse bore A5 that provides the throughway for the outlet 5 for mixed or blended water. The other flange A3 is solid. Two spaced apart threaded closed bores A6 are provided in the flange A2 on either side of the opening AA, and two similar and aligned bores A7 are provided in the flange A3· The bottom wall A8 of the recess 38 has a centra, circular clearance opening A9 that extends through a rear flange 50. The external profile of the flange 50 is channelled and the flange 50 is complementary to an inner recess 51 in the mounting backplate 20 (Figure 5)The mounting backplate 20 is of dished circular form having a flat central wall 52 in which two opposed holes 53 are provided for fixing the backplate 20 to the wall 2 by suitable fixings (not shown). An inner skirt formation 5A defines the recess 51 into which the rear flange 50 of the mixer body 17 is received as a substantially complementary fit. - 12 The outer rim flange 21 of the backplate is provided with two arcuately spaced radially extending bores 55 extending through the inner skirt 5A into which bores grub screws 56 are rece i ved.

The rear annular flange 50 of the mixer body 17 has the Vshaped groove 57 and this is aligned with the open ends of the bores 55· According, to locate and secure the mixer body 17 to a wall 2, firstly the backplate 20 is fixed to the wall, and then the rear flange 50 is seated in the recess 51 aligning the outlet 5 in this arrangement to the bottom underside. The grub screws 55 are then tightened to secure the mixer body rigidly to the wall. It will be understood, that by changing the position of the body 17 relative to backplate 20, the outlet 5 can be orientated as a top outlet or a side outlet as desired.

The mixer body 17 includes the respective similar hot and cold inlet bosses 28,29 to which the respective similar inlet elbow members 26,27 are connected.

As seen in Figure 5» the hot inlet boss 28 has a through bore providing the hot inlet 3^· The outer face of the boss 28 is stepped providing a first step 58 carrying an 0-ring seal 60 and a second step 62 which is formed with three similar arcuately spaced pockets 6A. The pockets 6A are spaced about 90° and the selected one for the required relative position receives the end of the grub screw 30 carried by the hot inlet elbow 26. The bore of the hot inlet elbow 26 is similarly stepped to seat over and abut the shoulders formed by the steps 58,62 to locate and seal the inlet elbow 26 to the boss 28 in the required position. The cold inlet boss 29 has a first step 59, an 0-ring seal 61, a second step 63 and pockets 65 for similar co-operation with the cold inlet elbow 27· As will now be understood, in this embodiment, the hot and cold inlet elbows 26,27 are located and secured in that selected - υ position on the respective hot and cold bosses 28,2$. For alternative top or bottom water supply connections, the inlet elbows can be located at one or other of the alternative positions of the respective pockets 6(,65.

As will now be appreciated, the special design and construction of the mixer body, inlet elbow connections and the mounting backplate facilitate simple fixing and fitting for a range of installations of water supply pipes and appliance connections.

The cartridge unit 15 will now be described with reference also to Figure 8 which depicts the unit 15 from the one side showing the hot inlet passageway. The other side is similar.

The cartridge unit 15 provides a sealed housing comprised of a cartridge body 66 assembled from complex shaped mouldings of selected plastics with the mouldings being welded or bonded together to provide a sealed unitary construction.

The cartridge body 66 includes a closure member 67 and the porting member 39 of generally hollow cylindrical form from which projects two opposed buttress mountings 68,69 in which respective similar hot and flow control valve assemblies 70,71 are carried. The rear annular end wall 72 of member 39 has an internal thread and this receives a hot seat assembly 73· The other end of the member 39 is formed with a transverse top flange 7( of generally rectangular plan shape. Each lateral portion of flange 7^ is symmetrical and formed with an outlet port opening 75 of the same sectional profile as the outlet opening (( of the mixer body 17.

The closure member 67 has an annular flange portion 78 of which the outer rim 77 has substantially the same profile as the mixer body flange (5· The underside of the flange portion 76 is formed with a substantially rectangular groove or channel 78 in which a complementary rib formation 79 seats with the rib being welded or bonded in the groove 78 to unite and seal the two members 39,87 together. - u The flange portion 76 has two spaced apart holes 80 on one lateral side and two other spaced holes 81 on the other side, and these holes 80,81 are arranged for respective alignment with the bores 46,47 in the flange 43 of the mixer body 17.

The cartridge unit 15 is dismountably fitted to the mixer body through the portion of the porting member 39 including the mountings 68,69 which is located and received in the recess 38 of the mixer body 17· When the porting member 39 is received in the recess 38, the bores 46,47 and holes 80,81 are aligned and four screws 82 are inserted through the holes 80,81 and engages in the bores 46,47 to secure the cartridge unit 15 to the mixer body 17When the cartridge unit 15 is received in the recess 38, each of the side walls 36,37 is in sealing engagement with an 0ring 83,84 carried respectively by the hot and cold buttress mountings 68,69 and the hot and cold inlets 34,35 of the mixer body 17 are aligned properly with the cartridge mountings.

In addition, one of the two outlet port openings 75 in the lateral portion of the flange 74 is aligned and in register with the outlet opening 44 formed in the body flange 42 whilst the other outlet port opening 75 is seated on the plain face of the body flange 43 and that outlet port 75 is closed.

As will now be appreciated, the cartridge unit 15 is dismountably fitted to the mixer body 17 by just four screws, and the cartridge unit can be located in either of two opposed positions in the mixer body depending on the hot and cold inlet arrangement. In either position, one of the outlet port openings 75 is in register with the outlet opening 44 leading to the hose and appliance to which the mixed or blended water is d i scharged.

This arrangement enables the variations for installation requirements to be accommodated in a simple manner.

The closure member 67 of cartridge body 66 has a hollow stepped cylindrical support portion 85 that extends from the - 15 flange 76. A shroud retainer 86 is seated on the portion 85 nearest to the flange 76 and is located on a narrow ledge. The shroud retainer 86 has two opposed axially extending walls 87 terminating in lateral support wings 88 of which the outer edge faces 8$ are profiled to complement the internal face of the waisted shroud trim Ik. Each wall 87 is formed with a leg 20 terminating in a foot 91 that extends and projects beyond the plane of the wings 88.

The shroud retainer 66 is made of a strong resilient plastics material and the opposed walls 87 and legs 90 can be resiliently displaced 'inwardly by pushing the shroud trim Ik over the feet 91 to a retained position (as shown in Figure 6) in which the opposed feet 91 snap over and engage on an internal annular flange 92 of the trim lk. A pair of axial lugs 93 1b extending from the flange 92 are provided to locate the shroud trim Ik in the proper angular position by engaging within cutouts (not shown) formed in each wing 88 and through which cutouts each leg 90 extends.

Accordingly, the shroud retainer 86 provides a simple form of retention means by which the waisted shroud trim 1k can be mounted and dismounted on the cartridge unit 15 without need for any special tools or skill.

The support portion 85 of the closure member 67 of the body 66 also mounts a flow spindle 9^+ having a hollow cylindrical body 95 formed with an external drive thread 95. The body 95 is received on the support portion 85 for relative rotation. A flow control yoke 97 has an annular internally threaded drive collar 98 engaged with the thread 96 of the spindle 9k for actuation of the flow control valve assemblies 70,71 (to be described later herein).

The front end of the body 95 has a radially extending flange 99 from which extend three arcuate guide wall portions 100 with retaining legs 101 having end feet 102 projecting axially - 16 therebetween and beyond. The body 95 is made of a resilient plastics material and the legs 101 are resiliently displaceable relative to the flange 99.

As shown best in Figure 6, the flange 99 with the guide walls 100 ccmDlements the cylindrical profile of an inner skirt 103 of the flow control knob 12 which is aaapted to seat over the flange 99 and to be dismountably retained thereon by the legs 101. The knob 12 has an internal annular flange 104 formed with three arcuately spaced cut-outs 105 through which the legs 101 are arranged to extend with the feet 102 snapping over and engaging the adjacent edge of the flange 104.

Accordingly, the flow control knob 12 is located on and dismountably retained on the flow spindle 94 by the resilient engagement of the legs 101 with their feet 102. The knob 12 can be mounted and dismounted on the cartridge unit 15 without any special tools or skills.

A circlip 106 is mounted on the support portion 85 of the closure member 67 to retain the flow spindle 94 thereon. The front cylindrical end portion of the support 85 is formed with a series of axially extending V-shaped teeth 107· A flow stop ring 108 having internal formations locating on the teeth 107 is mounted on support 85. The underside of the stop ring 108 has a stop lug 109 (Figure 6) and this provides a fixed stop engageable by either one of two arcuately spaced limit buttresses 110 (Figure 5) to limit the angular rotation of the flow control knob 12.

The stop ring 108 has a series of axially extending serrations 111 around the external cylindrical face. The temperature indicator trim 10 is of dished annular form having an Inner hub flange 112 which has formations to engage with the serrations 111 to locate the trim 10 against rotation relative to the stop ring 108. The trim 10 also has two diametrically opposed location rebates 113 (Figure 5) which are for visual alignment when the temperature control knob 7 is fitted. - 17 The extreme front end of the support 85 beyond the teeth 107 is formed with a central annular boss 114 of smaller diameter than the main part of the support. A tem.Derature stop hub 115 is located over the boss 1,4 and limit stop abutments (not shown) are provided both on the hub 115 and the boss 114 to limit relative rotation of the hub 115 by the temperature control knob 7 to about 180°.

The hub 115 has an internally splined bore ,16 1U with a smaller plain hole 117 through the end wail.

The hub 115 is secured by a headed screw 118 extending through the hole 117 to the splined one end of a temperature spindle 119 seated within the support portion 85 of the closure 67. A wavy spring washer 120 is trapped under the outer skirt 121 of the hub 115 and the stop ring 108, and another similar wavy spring washer 122 extends between the shroud retainer 86 and the inner end of the body 95 of the flow spindle 94.

The two washers 120,122 provide the spring bias to maintain and urge the assembled parts secured by the screwed down hub together correctly.

The hub 115 further comprises opposed location blocks 123 that extend from the centre of the hub and which terminate with part cylindrical side faces 124 aligned substantially with the peripheral face of the outer skirt 121. At the conjunction of the faces 124 and the skirt 121 the hub is formed with opposed radially projecting arcuate retention ribs 125. - 18 The temperature control knob 7 has an internal recess 126 underlying the cross grip 8 shaped to receive the central portion of the hub 115 with the blocks 123- The recess 126 is defined at each opposed end by resilient legs 127 having feet 128 arranged respectively to snap over the ribs 125 to secure and retain the knob 7 on the hub 115 whilst also covering and enclosing the securing hub screw 118.

As will now be appreciated, the temperature control knob 7 can be fitted and removed in a simple manner not requiring special tools or expertise.

According to the primary objective of this invention, the features as aforedescribed provide a mixer in which the mixer body can be fitted and plumbed in to suit all typical hot and cold and outlet orientations, and a sealed cartridge unit can be fitted and secured thereto by just four fixing screws. The knobs, trims and shroud can be fitted or removed simply, and the cartridge unit can be changed, replaced 2θ or re-orientated without special skills. - ,9Now turning to the operation of the mixer 1, all of the functional parts for admitting hot and cold water, mixing or blending the water to a selected temperature for discharge are comprised within the cartridge unit 15. The flow control knob 12 controls the actuation of the hot and flow control valve assemblies 70,71 which are respectively carried in the buttress mountings 68,62 as will now be described.

The flow spindle 9k has the external drive thread 96 on the cylindrical body 95. The flow control yoke 97 has the annular threaded drive collar 98 engaged therewith. Accordingly, when the flow spindle 9k is rotated by the knob 12, the yoke 97 is moved axially between limit positions corresponding to ful’ly open and closed. The yoke 97 Includes opposed lateral platforms 129,130 associated respectively with the similar hot and cold valve assemblies 70,71· Each platform 129,130 is similar and includes a support grommet 131,132 through which a screw 133,13k extends engaging a valve plate carrier 135,136.

For identification, preferably the grommets 131,132 are marked or coloured red/blue to give a visual guide to the hot and cold 2ϋ inlet sides of the cartridge unit 15Each carrier 135,138 is similar and has a hanger stem 137 and a substantially rectangular frame 138 in which is mounted a plate 139 for movement with the carrier between an inner fixed plate IkO and an outer fixed plate 1kl. Details of the plates in inverted position are shown in Figure 10 and will be described for the hot valve assembly 70.

The outer plate Ikl is located and seated in the buttress mounting 68 engaging a silicon seal lk2. The plate Ikl has two transverse through openings 1k3, the slidable plate 139 has through openings 1kk and the inner fixed plate IkO has a single through opening lk5 which has a divergent flow face 146. The inner plate IkO engages an inner silicon seal 147. - 20 As shown in the views of Figures 5 and 7, the plates 141,139 and 140 are positioned in the fully open position with the through openings in aligned register so that the resDective het and cold inlet passageways 148,149 are open to the respective inlets 34,35- On axial movement of the yoke 97, then each carrier 135,136 is moved axially simultaneously to slide the movable plates 139 between the fixed plates 140,141 so that the through openings 144 are moved out of register to reduce the water flow through the inlet or on maximum movement to close the T 0 i n i e t.

Accordingly, by rotation of the flow control knob 12, flow is controlled through both the hot and cold inlets 148,149 and when the knob 12 is in the closed limit position, both valve assemblies 70,71 are in the closed position to isolate the cartridge unit 15 from the mixer body 17. This particular arrangement has advantages for removal or fitting the cartridge unit 15 to the mixer body 17· The valve plates 139,140 and 141 are each made of a hard and strong ceramic material, and are resistant to corrosive effects of water. in addition, any scale or debris build up on the plates will be removed due to the se1f-cleaning action of the sliding plate 139 when moving relative to the fixed plates 140,141.

The specific shape, size and profiles of the through openings may be varied to suit a range of water flow rates/water pressures. This enables a range of cartridge units to be provided for respective specific ranges dependent of water pressures and flow rates with the range of units each being for fitting or installing to the same mixer body. 3θ This arrangement of interchangabi1ity of cartridge units provides economic advantages when changes in a plumbing installation may be made or supply pressures are varied as the fitting of a totally new shower or like appliance may be avoided. - 21 The temperature of the nixed or blended water discharged through the outlet 45 is controlled by the temperature control knob 7 which, as previously described is rotatable between limit stops. In the drawings of Figures 5, 6 and 7 the parts are deDicted in an intermediate position warm selected mode.

The knob 7 is fitted to the hub 115 which is secured for driving engagement to the splined end 150 of the temperature spindle 115- An internally threaded bore 151 with a closed end 152 is provided in the spindle 119 opposed to the end 150· A drive nut 153 is mounted in threaded engagement within the bore 151. The drive nut 153 has a star-profiled radial flange 154 which engages with a similarly profiled section 155 of the inner wall of the tubular portion 85 of the closure body member 67. Thus the drive nut 153 is restrained from rotation when the spindle 119 is turned but is caused to move axially towards or away from the closed end 152 of the spindle.

A wax-filled thermostat 156 having an actuator rod 157 projecting from one end through a flexible boot 158 extends axially in the cartridge body 67 and the closure member 68. The actuator rod 157 extends in and engages the end wall of an axial plunge recess 159 within the drive nut 153.

The end 16O of the thermostat 156 remote from the rod 157 is located and supported on the central core 161 of a spider support 162 of which the outer rim 163 engages an internal webbed shoulder 164 of a shuttle valve 165. The thermostat 156 extends through a helical spring 166 mounted between an internal shoulder 167 in the portion 85 and an extension flange 168 of the shuttle valve 165 with the spring 166 applying an axial force to the shuttle valve 165· Another spring 169 acts in opposition to the shuttle bias spring 166 and this spring 169 is mounted and located within a recess 170 provided in the hot seat housing 171. A spring guide 172 is also received and located in the recess 170 and the - 22 guide 172 has a central boss 173 which engages the core 161 of the shuttle support 162.

The spring forces are rated to act on the shuttle valve 165 which, in turn, is acted on by the thermo-responsive movement of the thermostat 156.

The hot inlet 148 opens to a hot inlet port 174 formed in the cartridge body 66 to provide an internal passageway for hot water within the body 66. Similarly, the cold inlet 149 opens to a cold inlet port 175 also formed in the cartridge body 66 but opposed to the hot inlet port 174 and spaced axially therefrom. The interna] passageways for hot and cold water from the respective inlet ports 174,175 are separated by an annular seal housing assembly 176 of which the seal is in engagement with the substantially cylindrical wall 177 of the shuttle valve 165The shuttle valve 165 serves as a proportioning valve to control the relative proportions of hot and cold water admitted to a mixing chamber 17θ extending within the shuttle extension flange 168 and within the cartridge body 66 and tubular portion 85 of the cover, and through which mixing chamber the thermostat 156 also extends. One annular end face 179 of the shuttle provides a seal face co-operating with a hot seat 180, and the other annular end face 181 of the shuttle provides a seal face co-operating with an annular cold seat 182 formed by an * internal shoulder in the cartridge body 66.

Each of the annular seal faces 179,181 of the shuttle are of tapering form to provide a small contact seal area, and in the case of build up of scale or debris on the co-operating hot or cold seats, the action of the sealing engagement will bite into and break up any deposit. In particular, the deposition of scale 3θ in hard water areas often rises most in the hot inlet passageways, and in this embodiment a special hot seat 180 is provi ded. - 23 The hot seat l80 is made of a thermoplastic elastomeric material that is resiliently deformable so that on application of sealing loads, the local deformation of the seat will assist in loosening or dislodging debris. The hot seat l80 is held in place by a stepDed ring 183 located in the hot seat mounting 171, and an annular clearance 18A is provided to accommodate such resilient deformation.

The hot seat assembly 73 is arranged for relative adjustment as may be required to ensure full closure on operation of the shuttle valve. The mounting 171 has an external thread 189 engaged with a threaded entry 190 at the rear of the cartridge body 66, and a spigot portion 191 of the mounting 171 carries a seal 192. Special formations 193 on a central boss 19A of the mounting 171 are provided for engagement by a tool, and scale marks 195 are provided on the outer rim 196 of the mounting to indicate the set or adjusted position.

The mixing chamber 178 opens into an outlet chamber 185 that is defined mainly by the closure member 67 having a substantially rectangular shaped domed wall. The outlet chamber 185 has two opposed outlets 186,187 (Figure 6), but as previously explained, one outlet 186 will be closed by the plain flange A3 of the mixer body 17 whilst the other outlet 187 is aligned with the outlet opening (( in the flange (2 of the mixer body.

The operation and use of the invented mixer will now be described assuming that the flow control knob 12 is off, and the temperature setting is at a warm position.

The flow control knob 12 is turned, and the yoke 97 is moved carrying the central sliding valve plates lAl to the open position (as shown) opening the respective hot and cold inlet 1A8,1A9.

Hot and cold water flows into the mixing chamber 17θ where the wax-filled thermostat will respond to the water temperature by expanding or contracting with the rod 157 being pushed out or - 24 retracted. If the mixed water temperature causes expansion, the rod 157 engaging the drive nut 153 at its selected position will produce the reaction to move the shuttle valve 165 towards the hot seat ISO against the return spring 16° to reduce the inward flow of hot water. If the mixed water temperature decreases then the overall length of the thermostat shortens, and due to the force of the spring 16° the shuttle valve moves away from the hot seat 1 SO to increase flow of hot water into the mixing chamber.

The position of the drive nut 153 determines the responsive movement of the thermostat 156 applied to the shuttle valve 165. There is a continuous thermo-response by the thermostat 156 as water flows through the mixing chamber so that the temperature of discharged water is maintained substantially constant by the proportioning action of the shuttle valve 16515 In the arrangement of the respective inlets, the shuttle valve and the mixng chamber, the flow path of the water is maintained in an axial direction over the main body of the thermostat so as to obviate delays in thermo-response of the thermostat. 2U The shuttle valve acts as a proport ioning valve and is independent of differences or changes in water pressure from the respective inlets.

In the embodiment described, the water supply pipes are arranged for back inlet connection with inlet elbows that are visible on the wall to which the mixer is fitted.

In other installations the mixer may be installed on a wall or partition with the water supply pipes being connected to the mixer body behind or within a recess in the wall or partition.

In such an arrangement, the mixer body is secured by the 3θ mounting backplate (as described previously) and this may be secured within a recess or to a partition bracket.

The inlet connections to the mixer body may be completed by any suitable gland connections to fit the water supply pipes. - 25 Preferably, for such an installation, the mixer body and part of the porting member are enclosed by a shroud. The shroud may be like a cup into which the rear portion of the mixer body and cartridge is received with the cup being located secretly within the recess or behind the partition.

To finish tne outward visual appearance of the mixer, a dished or saucer shaped annular trim member may be located on the cartridge unit. This trim member will cover the adjacent outer face of the wall or partition and the outer or front part of the mixer with the flow control knob and temperature control knob will project therefrom. In such an arrangement, usually the outlet is connected to a fixed pipe also behind the wall or partition and this leads to a fixed appliance such as a fixed shower head.

Other alternatives or variations are deemed within the scope of this invention.

Claims (5)

1. A thermostatic mixer comprising a body having hot and cold water inlets for connection respectively to hot and cold water supplies and having a mixed water outlet, a cartridge unit having 05 a sealed housing with a porting member having opposed hot and cold inlet ports and opposed outlet ports, the porting member being received in a seating in the body with the hot and cold inlet ports and one outlet port in communication with the respective inlets and outlet of the body, the cartridge housing mounting respective flow control valve assemblies for actuation to control flow of hot and cold water through respective passageways leading to a shuttle valve mounted for axial movement between hot and cold seats to vary the relative proportions of hot and cold water admitted to a mixing chamber in communication with one of the two outlet ports, a thermostat responsive to temperature of water in the mixing chamber to control movement of the shuttle valve in accordance with adjustable selection of the mixed water temperature, and the cartridge unit having retention means for detachably retaining on the unit a flow control member arranged to actuate the flow control valve assemblies and for detachably retaining a temperature control member arranged to control thermostatic response of the shuttle valve, and both the cartridge unit and the mixer body having mounting means arranged for releasably securing the cartridge unit to the mixer body in 25 one of two opposed positions and in each position only one of the outlet ports of the unit is in communication with the body outlet whereby the cartridge unit can be dismounted from the mixer body or can be located and secured to the mixer body in one of two selected positions dependent on the connections to hot and 30 cold water supplies.

2. A mixer according to Claim 1 wherein each flow control valve assembly comprises a sliding plate valve. - 27

3. A mixer according to Claim 2 wherein both flow control vaives are actuated by a common member arranged to be operatec by the flow control member retained on the cartridge housing, k.

4. A mixer according to Claim 2 or Claim 3 wherein the sliding 05 plate valves each comprise ceramic elements. 5· A mixer according to Claim k wherein each sliding plate valve assembly is similar and comprises inner and outer fixed ceramic elements with a slidable ceramic valve element extending therebetween mounted for actuation by a yoke operably connected 10 to the flow control member. 6. A mixer according to Claim 5 wherein each of the ceramic elements is formed with a throughway and the throughway of the sliding element is aligned with the throughways of the fixed elements in the open position and in the closed position is out 15 of register to close the associated inlet and the passageway leading to the shuttle valve. 7. A mixer according to Claim 6 wherein the size and shape of the throughways is selected to minimise pressure loss through the valve plates. 20 8. A mixer according to Claim 6 or Claim 7 wherein the throughways are generally of rectangular shape. 9. A mixer according to Claim 8 wherein the sliding element and one fixed element each have two through openings and the other fixed element has a single through opening. 25 10. A mixer according to any preceding Claim wherein the cartridge housing is made of a plastics material and is optionally a welded or bonded assembly of mouldings defining the internal mixing chamber within which the thermostat and shuttle valve are supported and arranged for co-axial movement. 30 11. A mixer according to any preceding Claim wherein the retention means provided on the cartridge unit for locating and supporting the temperature control member are arranged so that the temperature control member, such as a manually rotatable - 28 knob, can be removed or fitted as may be required on installation or replacement of the cartridge unit. 12. A mixer according to Claim 11 wherein such retention means comprises resilient limbs on the temperature control member 05 arranged to engage with formations on a hub with a snap-on or snap-off action. 13· A mixer according to any preceding Claim wherein the retention means provided on the cartridge unit for locating the flow control member comprises resilient limbs arranged to engage 10 with formations in the flow control member, such as a rotatable knob, so that the flow control member can be engaged and disengaged in a simple snap-action. 14. A mixer according to any preceding Claim including trim members or shrouds which fit on or over the cartridge unit or the 15 mixer body to enclose the cartridge unit and the mixer body. 15. A mixer according to Claim 14 wherein the trim or shroud members are detachable. 16. A mixer according to any preceding Claim wherein the porting member is assembled and bonded to a closure member. 20 17. A mixer according to any preceding Claim wherein the porting member provides the passageways respectively for hot and cold water and defines a cold seating engageable by the cold seat of the shuttle valve. 18. A mixer according to Claim 17 wherein the porting member 25 further provides a mounting for an adjustable hot seating for engagement with the hot seat of the shuttle valve. 19. A mixer according to Claim 18 wherein the cold seating and the hot seating are opposed to each other and are of annular form with the shuttle valve being co-axially arranged for axial 30 movement between the respective hot and cold seatings. 20. A mixer according to Claim 18 or Claim 19 wherein the hot seating is comprised in a mounting supported in the cartridge porting member and arranged for relative adjusting movement to - 23 vary the position of the hot seating as may be required for the axial movement of the shuttle valve controlled by the thermostat. 21. A mixer according to any one of Claims 18 to 20 wherein the hot seating comprises an annular seating member of a 05 thermoplastics elastomeric material. 22. A mixer according to any one of Claims 18 to 21 including an index reference visible on the outside of the cartridge unit for indicating the set or adjusted position of the adjustable hot seat i ng . 10 23. A mixer according to any preceding Claim wherein the thermostat comprises an elongate hollow body filled with a thermally responsive wax that acts on an actuator rod projecting axially from one end of the thermostat and which extends or retracts relative to the body in response to changes in volume of 15 the wax on change of temperature of water in the mixing chamber in which the body extends. 24. A mixer according to Claim 23 wherein the other end of the thermostat body is seated in a support member for the shuttle valve arranged co-axially with the thermostat body. 20 25. A mixer according to Claim 24 wherein co-axial spring means acts between the thermostat body and the shuttle valve to maintain the shuttle valve in engagement with the support member. 26. A mixer according to Claim 25 wherein the thermostat is also acted on by return spring means acting in opposition to the co25 axial spring means. 27· A mixer according to Claim 26 wherein the return spring means is seated within a recess provided in the hot seat mounting and also acts as a safety overload spring for the thermostat. 28. A mixer according to any one of Claims 23 to 27 wherein the end of the actuator rod of the thermostat is received within a recess in a drive nut which is arranged for adjustable axial movement through the temperature control member to control the responsive movement of the shuttle valve between the hot and cold - 30 seatings or thermo-responsive changes of the thermostat to the temperature of water in the mixing chamber. 25· A thermostatic mixer substantially as hereinbefore aescrioed with reference to Figures I to 12 of the accompanying drawings.

5. 30· An ablutionary installation comprising a thermostatic mixer according to any preceding Claim arranged to discharge temperature controlled mixed or blenaec water through the outlet to a shower head or spray head or other ablutionary appliance. Dated this the 10th day of June, 1991