GB2437094A

GB2437094A - Water mixing valve with single control opening

Info

Publication number: GB2437094A
Application number: GB0607517A
Authority: GB
Inventors: John Patrick Cheek; Matthew Robert Riley
Original assignee: Aqualisa Products Ltd
Current assignee: Aqualisa Products Ltd
Priority date: 2006-04-13
Filing date: 2006-04-13
Publication date: 2007-10-17
Also published as: GB0607517D0

Abstract

A water mixing valve comprises first and second water inlets 12,14 a mixing chamber 50 and a control member 24 for controlling flow of water from the first and second water inlets to the mixing chamber. The control member includes a plate 30 with a first surface 34 for sealing with the first and second water inlets and a second surface opposite the first surface, the control member being movable relative to the first and second water inlets substantially only rotationally about a central axis substantially perpendicular to the first surface. The first and second water inlets are positioned substantially on a common circumference (60, Fig. 6a) and the plate defines a single control opening 32 extending arcuately substantially along the common circumference. The control opening may have a width in a radial direction which varies along its arcuate extent, between a minimum width at either end (32a, 32b, Fig. 6a) and a maximum width at a central region (32c, Fig. 6a). Rotation of the plate causes variation of the amount of water flowing from each water inlet into the mixing chamber (Figs. 6a-6d).

Description

WATER MIXiNG VALVE The present invention relates to a water mixing

valve and, more particularly, to a water mixing valve having two waterinJets, for instance for receiving respectively hot and cold water, and a mixing chamber for mixing flows from the two water inlets.

Previously, a large number of different designs of water mixing valves have been proposed, for instance for use in shower installations.

It has been proposed to blend or control two water inlets using a disc-shaped rotatable control member, the control member having respective tapered openings adjacent the water inlets. As the disc is rotated, the tapers move over the water inlets so that the open area through the disc presented to each water inlet increases or decreases according to movement of the taper. By providing the narrowest sections of the tapers end-to-end and the widest sections of the tapers end-to-end, rotation of the disc causes flow from one inlet to increase whilst flow from the other inlet decreases. This can be used to mix hot and cold water.

EP-A-1 128 105 describes in detail such a water mixing valve. In particular, it describes this arrangement of a water mixing valve where the disc can be rotated by means of a motor, for instance under the control of a control system including at least a water temperature sensor downstream of the mixing chamber.

Although this arrangement is extremely advantageous in its performance, the present invention recogrnzes for the first time how to reduce the size of the overall water mixing valve whilst also providing other significant advantages and a reduction in the cost of components. In particular, the present invention recognises for the first time the fact that respective openings for the two water inlets can be provided simultaneously by different portions of the same single control opening.

Thus, according to the present invention, there is provided a method of controlling the flow of water from first and second water inlets to a mixing chamber using a control member, the control member having a plate with a first surface for sealing with the first and second water inlets and a second surface opposite the first surface, the control member being movable relative to the first and second water inlets substantially only rotationally about a central axis substantially perpendicular to the first surface, the plate defining first and second elongate throughholes for controlling flow of water from the first and second water inlets, the first and second elongate throughholes extending between the first and second surfaces and along arcs centred on the central axis having radii corresponding to the respective first and second water inlets, the method including: positioning the first and second water inlets substantially on a common circumference; and providing the first and second elongate throughholes together as a single control opening extending arcuately substantially along the common circumference.

Also, according to the present invention, there is provided a water mixing valve having: first and second water inlets; a mixing chamber; and a control member for controlling flow of water from the first and second water inlets to the mixing chamber, the control member comprising a plate with a first surface for sealing with the first and second water inlets and a second surface opposite the first surface, the control member being moveable relative to the first and second water inlets substantially only rotationally about a central axis substantially perpendicular to the first surface; wherein the plate defines first and second elongate throughholes for controlling flow of water from the first and second water inlets, the first and second elongate throughholes extending between the first and second surfaces and along arcs centred on the central axis having radii corresponding to the respective first and second water inlets; and the first and second water inlets are positioned substantially on a common circumference and the first and second elongate throughholes are provided together as a single control opening extending arcuately substantially along the common circumference.

In functional terms, the plate of the control member still has first and second elongate throughholes which control the flow from the first and second water inlets respectively. However, the two elongate throughholes are formed from a single continuous elongate aperture forming the control opening. The present invention recognises for the first time that, although both water inlets feed into the same single control opening, any bleeding of flow from one water inlet circumferentially along the elongate control opening towards the other water inlet will be insignificant to the performance of the water mixing valve. This is quite counterintuitive and the skilled person would have expected the water inlets to require their own respective control apertures for instance as discussed in EP-A-1 128 105. Indeed, in arrangements such as described in EP-A-1 128 105, in the off position with both water inlets closed, a first water inlet is positioned between the two large-width ends of the respective throughholes and a second water inlet is positioned between the two small-width ends of the respective throughholes. The skilled person would expect this arrangement to be essential for correct operation of the device. When the disc is rotated, the first water inlet is brought into alignment with the large-width end of one of the throughholes. Then, progressively, the second water inlet moves along the other throughhole from its small-width end to its large-width end while the first water inlet is moved towards the small-width end of its throughhole. Clearly, this arrangement is not possible with the single control opening of the present invention and, hence, the skilled person would not have considered the single opening as a possibility. The present invention includes the recognition that, starting from an off-position, the first water inlet can first be moved over a portion of the single control opening functionally associated with the second water inlet and equivalent to the throughhole of the prior art associated with the second water inlet. This brings the water mixing valve to a state equivalent to the start state of the prior art arrangement. Movement to this state can be conducted quickly so that the user does not notice it. Alternatively, where the single control opening tapers from two small-width ends to a large-width central region, this initial involvement allows the flow rate from the first water inlet to be increased gradually to its maximum before any water from the second water inlet is mixed with it.

When the first and second elongate throughholes are brought together to form a single control opening, the total arcuate length required for the two throughholes is reduced such that it becomes possible to provide the control opening along a circumference of smaller radius than that used in the prior art. It is thus possible to reduce the overall size of the water mixing valve. Furthermore, since the water inlets seal with the first surface of the plate of the control member at a smaller tadius, any resistive forces resulting from friction between the water inlets and the first surface are reduced. It thus becomes possible to do without special low-friction property materials andlor to reduce the power of any motor driving the control member.

The control opening may include the first and second elongate throughholes extending end-to-end in an overlapping manner.

As will be appreciated, corresponding ends of the throughholes of the prior art arrangements will have corresponding widths in the radial direction. Hence, it is possible to use the same section of the control opening for two corresponding ends of the throughholes provided for the first and second water inlets respectively. In this way, the overall arcuate length of the control opening of the present invention is reduced still further as compared with thetwo-throughhole arrangement of the prior art and the advantages mentioned above become even more significant.

In the preferred embodiment, the two elongate throughholes overlap at their respective ends having the largest radial width. Thus, preferably, a central section of the control opening allows maximum flow from either one of the first and second water inlets when that one of the first and second water inlets is positioned adjacent the central section.

The control opening has a width in a radial direction. The width preferably varies along the arcuate extent of the control opening. In particular, it preferably varies between a minimum width at one end, a maximum width at a central region and substantially the minimum width at the other end.

Thus, in use, as the control member is rotated, a first minimum-width end of the central opening is brought into alignment with for instance the first water inlet and then the width presented to the first water inlet is increased progressively until the first water inlet is adjacent the maximum width at the central region. From there, the width presented to the first water inlet is then reduced until it is adjacent the second end of the control opening.

During this movement, preferably from the position at which the first water inlet is adjacent the central region, the second water inlet moves into alignment with the first end of the control opening. The width presented to the second water inlet then increases as the width provided to the first water inlet decreases.

The circumferential spacing of the first and second water inlets is preferably greater than the circumferential distance between at least one end of the control opening and the central region of the control opening. In this way, the control member can be rotated to a position where at least one of the first and second water inlets is open to a maximum and the other of the first and second water inlets is closed by the first surface of the plate.

Thus, the water mixing valve is able to provide full flow of at least one of the two inlets.

The circumferential spacing of the first and second water inlets may also be greater than the circumferential distance between the central region of the control opening and the other end of the control opening. In this way, the control member can be rotated to a position where one of the first and second water inlets is open to a maximum and the other of the first and second water inlets is closed by the first surface of the plate. It may also be rotated to a position where the other of the first and second water inlets is open to a maximum and the one of the first and second water inlets is closed by the first surface of the plate.

In this arrangement, the water mixing valve is able to provide full flow to either of the water inlets.

It will be appreciated that the minimum relative circumferential distances will depend partly on the circumferential extent of the water inlets.

preferably, the central region is provided substantially halfway between the one end and the other end of the control opening.

This allows a symmetric arrangement with equal mixing possibilities for both water inlets.

The circumferential spacing of the first and second water inlets is preferably less than the circumferential length unused by the arcuate extent of the control opening. In this way, the control member can be rotated to a position where both of the first and second water inlets are closed by the first surface of the plate. Thus, the water mixing valve can also be used as an on/off valve and prevent flow of water from both water inlets simultaneously.

It will be appreciated that the maximum spacing between the first and second water inlets will depend on their circumferential extent, but the outer circumferential extents of the two water inlets must be less than the circumferential length unused by the arcuate extent of the control opening in order to allow both inlets to be shut off simultaneously.

Preferably, the centres of the first and second water inlets have a circumferential spacing substantially equal to 1/3 of the total circumferential length. This arrangement allows maximum flexibility and functionality whilst using a minimum circumferential length.

The invention will be more clearly understood from the following description, given by way of example only, with reference to the accompanying drawings, in which: Figure 1 illustrates an overall shower system in which the present may be embodied; ) Figure 2 illustrates a water mixing valve housing which may embody the present invention; Figure 3 illustrates a mixed cross-section through the housing of Figure 2; Figure 4 illustrates a control member for use with the present invention; Figure 5 illustrates the control member of Figure 4 in conjunction with water inlets; and Figures 6(a) to (d) illustrate schematically movement of a control aperture relative to water inlets.

The water mixing valve of the present invention is particularly applicable to shower systems such as illustrated schematically in Figure 1 and can be embodied therein.

As illustrated, a water mixing assembly 2 receives a hot water supply 4 and a cold water supply 6, mixes hot and cold water according to the needs of the user and provides an output mixed-water flow 8 to a shower handset 10. The water mixing assembly 2 may use a water mixing valve of the present invention with a manual or motor-driven control member and may be thermostatically controlled or not.

An embodiment will now be described that uses a motor to drive the water mixing valve. In general, this embodiment follows the teaching of EP-A-1 128 105, but uses a control member having a plate with a single control opening.

igure 2 of the accompanying drawings illustrates a water mixing valve housing which may embody the present invention. The water mixing valve includes a first water ) inlet 12, a second water inlet 14, a mixed water outlet 16, a housing 18, a temperature sensor 20 and a motor 22 for operating the water mixing valve. The water mixing valve illustrated in Figure 2 can be constructed in the same way as that of EP-A-l 128 105 but with a different control member plate to be described below. Also, it should be noted that, in the preferred embodiment of EP-A-1 128 105, the first and second water inlets 12 and 14 are arranged diametrically with respect to the rotational axis of the control member. In the preferred embodiment of the present invention, the two water inlets 12, 14 are not provided on the same diameter, but are preferably spaced apart by one third of the circumference on which they are positioned.

Figure 3 illustrates schematically a mixed cross-section through the water mixing valve of Figure 2; the top half is sectioned through the axis of the valve and the bottom half is sectioned off-axis through the centres of the two inlets. Figure 4 illustrates the control member 24 used in the water mixing valve. As with the prior art valve of EP-A-1 128 105, the control member 24 of the preferred embodiment is a generally hollow member within which the mixing chamber 50 is formed. The control member 24 has at one end facing the two water inlets 12, 14 a plate 30 in which the control opening 32 is formed. As illustrated, the control opening 32 extends arcuately substantially along a circumference centred on the rotational axis of the control member 24 and plate 30. It also extends through the plate 30 from a first surface 34 facing the water inlets 12 and 14 to a second surface facing the water mixing chamber 50 defined inside the control member 24. )

As illustrated in Figure 5, the first water inlet 12 and second water inlet 14 are both arranged to seal with the first surface 34 of the plate 30. In the preferred embodiment, for instance in the same way as is described in EP-A-1 128 105, seals 42 and 44 are pressed into engagement with the first surface 34 so as to seal the first and second water inlets 12, 14 with the first surface 34 of the plate 30.

In the illustrated embodiment, a motor 22 is provided to rotate the control member 24 and plate 30 about their central axis. In this way, the control opening 32 defined in the plate 30 may be rotated relative to the first and second water inlets 12, 14.

Figures 6(a) to (d) illustrate schematically operation of the control member 24 and plate 30 in conjunction with the first water inlet 12 and second water inlet 14. These are described with reference to a notional circumference 60 centred on the central axis of rotation of the control member 24 and plate 30. The first and second water inlets 12, 14 are both centred on the circumference 60 and the control opening 32 extends as an arc along the circumference 60. The control opening 32 has a width in a radial direction and this width is at a minimum at either end 32a, 32b. At a central region 32c, the width is at a maximum. Thus, it tapers to a reduced width in either direction from the central region.

By rotating the control member 24 and plate 30 relative to the first and second water inlets 12, 14, the control outlet 32 is moved relative to the first and second water inlets 12, 14 and presents an opening of variable width to the mixing chamber 50. )

As an example, movement of the control opening 32 will be described for the first water inlet 12 acting as a cold water inlet and the second water inlet 14 acting as a hot water inlet.

As illustrated in Figure 6(a), the plate 30 is positioned such that the control opening 32 is not presented to either the cold water inlet 12 or the hot water inlet 14.

Hence, the water mixing valve does not allow any water to pass into the mixing chamber 50 and can be considered to be in an off state.

In the illustrated embodiment, the control member 24 and plate 30 are first rotated anticlockwise to the position illustrated in Figure 6(b). In particular, the end 32a of the control opening 32 moves along the circumferential path 60 under the cold water inlet 12.

As the control opening 32 continues to move in an anticlockwise direction, the control opening 32 progressively presents an opening of greater width to the cold water inlet 12 iS such that a higher flow of cold water is progressively allowed into the mixing chamber 50.

Figure 6(b) illustrates a position where the cold water inlet 12 is adjacent the central region 32c of the control opening 32 such that a maximum flow of cold water is provided from the cold water inlet 12 to the mixing chamber 50. This is equivalent to the start position of the prior art arrangement of EP-A-1 128 105.

In the preferred embodiment as illustrated in Figure 6(b), the end 32a of the control opening 32 is positioned just outside the hot water inlet 14 when the cold water inlet 12 is positioned against the central region 32c of the control opening 32. Thus, although no It j -opening is presented to the hot water inlet 14 such that no hot water flows from the hot water inlet 14 into the mixing chamber 50, any further anticlockwise rotation of the control opening 32 will result in a small opening being presented to the hot water inlet 14. As the control member 24 and plate 30 are then rotated progressively further anticlockwise, the hot-water inlet 14 will be presented with an opening of progressively greater width while the cold water inlet 12 is presented with an opening of progressively smaller width. In one preferred embodiment, the profile of the control opening 32 may be such that during this movement the total cross-section of the control opening 32 presented to the two water inlets is kept constant, such that a constant overall flow of water is provided to the mixing chamber 50, but with a varying proportion of hot and cold water.

Figure 6(c) illustrates an intermediate position where the hot and cold water inlets 14, 12 are both presented with an opening to the mixing chamber 50 such that a mixed water outlet is provided. The plate 30 can be rotated clockwise or anticlockwise to vary the proportions of hot and cold water and, hence, vary the temperature of the mixed water outlet. As illustrated, cold water inlet 12 is at a position intermediate the central region 32c and the end 32b. Similarly, the hot water inlet is at a position intermediate central region 32c and end 32a.

Movement of the plate 30 still further in an anticlockwise direction will result in the central region 32c of the control opening 32 being presented to the hot water inlet 14 as illustrated in Figure 6(d). Hence, in this position, a maximum flow of hot water is provided to the mixing chamber 50. In the preferred embodiment and as illustrated, at this position,

U

the end 32b of the control opening 32 has just passed the circumferential edge of the cold water inlet 12 such that the cold water inlet 12 is closed by the first surface 34 of the plate 30. Thus, in this position, only hot water is provided to the mixing chamber 50.

It will be appreciated that the plate 30 can then be rotated further anticlockwise such that the end 32b of the control opening 32 moves towards the hot water inlet 14 and the amount of hot water provided to the mixing chamber 50 is progressively reduced (while still no cold water is provided).

In one embodiment, it may be possible to rotate the plate 30 still further and return the water mixing valve to its initial off state as illustrated in Figure 6(a). )

Claims

CLAIMS

I. A water mixing valve having: first and second water inlets; a mixing chamber; and a control member for controlling flow of water from the first and second water inlets to the mixing chamber, the control member comprising a plate with a first surface for sealing with the first and second water inlets and a second surface opposite the first surface, the control member being moveable relative to the first and second water inlets substantially only rotationally about a central axis substantially perpendicular to the first surface; wherein the plate defines first and second elongate throughholes for controlling flow of water from the first and second water inlets, the first and second elongate throughholes extending between the first and second surfaces and along arcs centred on the central axis having radii corresponding to the respective first and second water inlets; and the first and second water inlets are positioned substantially on a common circumference and the first and second elongate throughholes are provided together as a single control opening extending arcuately substantially along the common circumference.

2. A water mixing valve according to claim 1 wherein: the control opening includes the first and second elongate throughholes extending end-to-end in an overlapping manner. )

3. A water mixing valve according to claim 1 or 2 wherein: the control opening has a width in a radial direction, the width varying along the arcuate extent of the control opening between a minimum width at one end, a maximum width at a central region and substantially the minimum width at the other end.

4. A water mixing valve according to claim 3 wherein: the circumferential spacing of the first and second water inlets is greater than the circumferential distance between at least one end of the control opening and the central region of the control opening such that the control member can be rotated to a position where at least one of the first and second water inlets is open to a maximum and the other of the first and second water inlets is closed by the first surface of the plate.

5. A water mixing valve according to claim 4 wherein: the circumferential spacing of the first and second water inlets is also greater than the circumferential distance between the central region of the control opening and the other end of the control opening such that the control member can be rotated to the position where one of the first and second water inlets is open to a maximum and the other of the first and second water inlets is closed by the first surface of the plate and to a position where the other of the first and second water inlets is open to a maximum and the one of the first and second water inlets is closed by the first surface of the plate.

6. A water mixing valve according to claim 3, 4 or 5 wherein: the central region is provided substantially halfway between the one end and the other end of the control opening.

7. A water mixing valve according to any preceding claim wherein: the circumferential spacing of the first and second water inlets is less than the circumferential length unused by the arcuate extent of the control opening such that the control member can be rotated to a position where both of the first and second water inlets are closed by the first surface of the plate.

8. A water mixing valve according to any preceding claim wherein: the centres of the first and second water inlets have a circumferential spacing substantially equal to 1/3 of the length of the total circumference.

9. A method of controlling the flow of water from first and second water inlets to a mixing chamber using a control member, the control member having a plate with a first surface for sealing with the first and second water inlets and a second surface opposite the first surface, the control member being moveable relative to the first and second water inlets substantially only rotationally about a central axis substantially perpendicular to the first surface, the plate defining first and second elongate throughholes for controlling flow of water from the first and second water inlets, the first and second elongate throughholes extending between the first and second surfaces and along arcs centred on the central axis

I

having radii corresponding to the respective first and second water inlets, the method including: positioning the first and second water inlets substantially on a common circumference; and providing the first and second elongate throughholes together as a single control opening extending arcuately substantially along the common circumference.

10. A water mixing valve constructed and arranged substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.

ii. A method of controlling the flow of water from first and second water inlets substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.