GB2073373A - Mixer valve - Google Patents

Abstract

The valve includes a pair of ceramic control discs 7, 8. As shown, disc 8 is fixed and has a round aperture 14 connected to a cold water inlet 5, and a round aperture 12 connected to a hot water inlet 4. Disc 8 is manually rotatable and has two preferably pear- shaped apertures 18, 16, for controlling flow from the cold and hot inlets to an outlet 6. Alternatively, the pear shaped apertures may be in the fixed disc and the round apertures in the rotatable disc. The rotatable disc is continuously rotatable from an off position (as shown) through a cold position in which the cold water aperture 14 is fully open and the hot water aperture 12 fully closed, to a hot position in which the cold water aperture 14 is fully closed and the hot water aperture 12 fully open. The tail portions of the pear-shaped apertures control flow in a complementary manner between the cold and hot positions. On leaving the pear-shaped apertures, water directly enters a mixing chamber and then passes to the outlet via central apertures 17, 13, in the control discs. <IMAGE>

Description

SPECIFICATION Mixer valve This invention relates to a mixer valve for controlling the mixing of hot and cold water supplied to a water discharger, such as a shower head.

It is important that such valves should be capable of accurate adjustment to control the temperature of the discharged water.

According to the invention a mixer valve for hot and cold water comprises a housing having a hot water inlet and a cold water inlet for connection respectively to hot and cold water supplies, and an outlet for connection to a water discharger, the housing containing a pair of control members arranged in face-toface sealing relationship, one of the members being fixed relative to the housing and the other being manually rotatable relative to the fixed member, the fixed member having two apertures connected respectively to the inlets, and the movable member having two apertures which are both connected to the outlet and which, by rotation of the movable member, can each be moved into and out of register with a respective aperture of the fixed member so as to form two pairs of co-operable apertures for controlling communication between the hot and cold water inlets respectively and the outlet, one aperture of each pair having a head portion which is registerable with the other aperture of the pair, and a tail portion which serves to gradually restrict communication between the co-operable apertures on rotation of the movable member.

By using apertures having such head and tail portions it is possible to extend the angle of rotation of the movable member between the maximum and minimum temperature positions so that very fine control over the temperature of the water flowing from the outlet can be achieved, whilst using a relatively simple valve arrangement.

In a preferred form of valve construction, the movable member is continuously rotatable about a single axis between a position in which both inlets are closed, through a second position in which the cold water inlet is fully open to the outlet and the hot water inlet is fully closed, to a third position in which the hot water inlet is fully open to the outlet and the cold water inlet is fully closed, communication between the inlets and the outlets being controlled in a complementary manner during rotatibn of the movable member between the second and third positions such that the cold water inlet is gradually closed and the hot water inlet is gradually opened.

Whilst the apertures which have a head and a tail portion may have a variety of shapes and still perform the necessary function, they are preferably pear-shaped.

Preferably the apertures in the movable member both oper7 on the downstream side of those apertures intb a mixing chamber and a passageway leads from the mixing chamber, through the movable and fixed members on a path which is co-axial with the axis of rotation of the movable member, to the outlet. This may give rise to a very compact form of construction. The mixing chamber is preferably formed by the interior of a cup-shaped spool which is keyed to the movable member.

Valves employing this form of construction have been found to be very quiet in operation and do not suffer from mixing noises to which mixer valves are sometimes prone. The valve also copes well with differences in pressure between the hot and cold supplies such as are often encountered in domestic installations.

Preferably the fixed and the movable members are both formed of ceramic.

The invention will now be further described, by way of example only, with reference to the accompanying diagrammatic drawings, in which Figure 1 shows a section through a mixer valve in accordance with the invention, Figure 2 shows a section on line A-A of Fig. 1, Figure 3 shows the movable member alone, and Figures 4a to $show the movable member in various positions relative to the fixed member.

Referring to Figs. 1 and 2, the mixer valve comprises a housing 1 which consists of a body portion 2 and a relatively fixed cover plate 3. The housing has a hot water inlet 4, a cold water inlet 5 and an outlet 6 for connection to a shower head.

The housing 1 contains a pair of ceramic control discs 7, 8. One of the discs 8 is located on a seating 9 formed on the housing 1 and is fixed relative to the housing by a pair of locating lugs 10 which are provided on the housing and are received in complementary recesses in the edge of disc 8. The disc 8 has three diametrically aligned circular apertures 12, 1 3 and 14. The two outer recesses 1 2 and 14, are equidistant from the centre of the disc 8 and communicate freely with the inlets 4 and 5 respectively via ports in seat 9, not shown. The intermediate aperture 1 3 is concentric with the disc 8 and communicates freely with the outlet 6 via a further port 1 5 in seat 9.

The other disc 7 is of the same diameter as the disc 8 and is located in intimate face-toface contact with that disc. The opposed faces of the two discs are ground flat and polished such that, in use, leakage of water between the opposed faces is virtually non-existant.

Disc 7 has a central aperture 1 7 which is permanently in register with the central-aperture 1 3 of the fixed disc 8. In addition, disc 7 has a pair of pear-shaped apertures 16, 18, the purpose of which is to control flow of water through the valve. However, before describing the rest of the valve and the way in which the valve operates, the arrangement and shape of the apertures 16, 1 8 will first be described in detail with reference to Fig. 3.

The pear-shaped apertures 16, 18, are arranged one on each side of a diameter B-B of the disc 7 such that one half of the disc is virtually a mirror image of the other. Each aperture comprises a head portion 1 9 of the same size and shape as apertures 1 2 and 14, and a tail portion 20 which extends away from the head portion generally circumferentially of the disc. The centres of head portions 1 9 lie on perpendicular radii of disc 7.The inner wall 21 of the tail portions, (that is, the wall which lies nearest ta the centre of the disc 7), lies on the circumference of a circle which is concentric with the disc and which just touches the inner edges of both head portions 1 9. The outer wall 22 of each tail portion is in the form of an arc which just touches the outer edge of the head portion and sweeps inwards to meet the other edge 21 of the tail portion. The tip of the tail is rounded slightly for convenience of manufacture.

Referring back to Fig. 1, the disc 7 is located over the open and of a cup-shaped spool 23 having an axial spindle 24 which extends through the cover plate 3. A cap 25 having a handle 26 is secured to the free end of the spindle 24 to enable the spool to be manually rotated within the housing. The disc 7 is secured to the spool 23 by a pair of axially extending pegs 27 formed on the spool, (Fig. 2), which are received in recesses in the edge of the disc 7, so that the disc 7 can be rotated by the spool relative to the disc 8. Two O-rings 28 are located in grooves, one between the spool 23 and the body portion 2 of the housing, and the other between the spool and the cover plate 3, for sealing purposes. The interior 29 of the cup-shaped spool 23 constitutes a mixing chamber.

In use, the mixer valve is connected to the hot and cold water supplies and to the shower head. Figs. 2 and 4a show the mixer valve in the 'off' position, in which the apertures 1 2 and 14 in disc 8 are closed by the disc 7.

Note that in this position the hot and cold supplies are isolated one from the other. The valve is operated by rotating the handle, so as to rotate the disc 7 relative to the fixed disc 8 in an anti-clockwise sense, looking in the direction of Fig. 2. When the disc has been rotated through about 45 , the head portion 1 9 of aperture 1 8 comes into register with aperture 14, as shown in Fig. 4b. Aperture 12, connected to the hot water supply, is still closed. Water is thus able to flow from the cold supply, via apertures 14 and 18, mixing chamber 29, central apertures 1 7 and 13, and outlet 6 to the shower head.

The temperature of the water issuing from the shower head can be increased by further rotation of the handle so that the area of aperture 1 4 which is open is gradually reduced by virtue of the tapering tail portion of aperture 18. Note that as disc 7 rotates it is the outer wall 22 of the tail portion which sweeps across aperture 14 to control the flow.

At the same time, hot water aperture 1 2 is gradually opened by the tail portion of aperture 1 6. Fig. 4c shows a condition in which both apertures 1 2 and 1 4 are partially open.

(In Figs. 2 and 4a to 4d, H indicates the hot water path, C indicates the cold water path, and M indicates the path taken by mixed water). In this condition, hot and cold water flows through the respective pairs of apertures 12, 16 and 14, 18, to the mixing chamber 29 where quiet and thorough intermixing of the hot and cold water takes place. The tem- perature of the water leaving the outlet 6 can be continuously adjusted between the tertiper- ature of the cold water passing through inlet 5, to the temperature of the hot water pasSing through inlet 4. Fig. 4d shows the disc 7 in the 'maximum temperature' position in which the head portion of aperture 1 6 is in register with hot water aperture 12, and cold water aperture 14 is fully closed.

It is not essential that the head portions of the pear-shaped apertures 16, 18, be of exactly the same shape and size as the apertures 1 2 and 14, as long as the two apertures can be brought into register without significantly restricting communication between the apertures. Also, the tail portions need not be exactly of the shape shown, as long as they serve to gradually close the apertures 1 2 and 14. Nevertheless, in practice pear-shaped apertures have been found to give the best results.

It is also important to realise that the pearshaped and the round apertures can be in either disc, and the pear-shaped apertures need not be in the same disc.

Claims (9)

1. A mixer valve for hot and cold water, comprising a housing having a hot water inlet and a cold water inlet for connection resp6c- tively to hot and cold water supplies, and an outlet for connection to a water discharger; the housing containing a pair of control members arranged in face-to-face sealing relationship; one of the members being fixed relative to the housing and the other being manually rotatable relative to the fixed member; one of the members having an aperture connected to the cold inlet and co-operable with an aperture in the other member to form a first pair of co-operable apertures, and another aperture connected to the hot inlet and co-operable with a further aperture in the other member to form a second pair of co-operable apertures; one aperture of each pair having a head portion which is registerable with the other aperture of the pair, and a tail portion; the arrangement being such that the rotatable member is continuously rotatable between a cold position in which the first pair of aper tures are fully open and the second pair of apertures fully closed, and a hot position in which the second pair of apertures are fully open and the first pair of apertures are fully closed; the aforementioned tail portions being arranged to control communication between the inlets and the outlet in a complementary manner during rotation of the movable member between the cold and hot positions such that the first pair of apertures are gradually closed and the second pair of apertures are gradually opened.

2. A mixer valve according to Clam 1, in which the control member having apertures connected to the hot and cold water inlets is the fixed one.

3. A mixer valve according to Claim 2, in which the apertures having head and tail portions are provided in the rotatable mem ber.

4. A mixer valve according to any preced ing claim, in which the apertures having head and tail portions are pear-shaped and the apertures that are co-operable with them are substantially circular.

5. A mixer valve according to Claim 2, in which the apertures in the rotatable member both open directly into a mixing chamber.

6. A mixer valve according to Claim 5, in which a passageway leads from the mixing chamber through the control members on a path which is substantially co-axial with the axis of rotation of the movable member, to the outlet.

7. A mixer valve according to Claim 6, in which the mixing chamber is formed by the interior of manually rotatable cup-shaped spool which is keyed to the movable member.

8. A mixer valve according to any preced ing claim, in which the rotatable member is continuously rotatable from an off position in which both pairs of co-operable apertures are fully closed, through the cold position to the hot position.

9. A mixer valve which is substantially as described with reference to and as shown in the drawings.