GB2042130A

GB2042130A - Mixing valves

Info

Publication number: GB2042130A
Application number: GB8001546A
Authority: GB
Original assignee: TOPLISS SHOWERS Ltd
Current assignee: TOPLISS SHOWERS Ltd
Priority date: 1979-01-18
Filing date: 1980-01-17
Publication date: 1980-09-17
Also published as: GB2042130B

Abstract

A mixing valve for domestic showers comprises rotary blending valve members 11, 12 each rotatable about an axis substantially perpendicular to a passage through the valve. Regulating means such as a control knob 39 rotates the valve member spindles 16 to simultaneously regulate the flow of hot and cold water into the mixing chamber 2 and thus the temperature of the water flowing out of the mixing chamber. Preferably as one blending valve member opens its passage, the other closes so that the net throughflow of water is substantially unaffected by the operation of the regulating means. Separate inlet throttle valves 20 and a mixing chamber outlet valve 6 are provided. <IMAGE>

Description

SPECIFICATION Mixing valves Field ofinvention The invention relates to mixing valves for use especially in shower installations.

Background of the invention A variety of mixing valves for shower installations are known. These generally may have a first control means for controlling the amount of water flowing out and a second blending control for regulating the temperature. The temperature can thus be pre-set before opening the first control means. Examples of such mixing valves are described in the British Patent Specifications 1,388,848 and 1,144,047.

In practice these valves have not turned out to be satisfactory; in many instances shower installations fall into dis-use for reasons which are not always clearly apparent. In the U.K. low water supply pressures are prevalent and it appears that the outflow of water is frequently insufficient. The temperature of the water flowing out may be difficult to regulate and vary in response to minor changes in the supply conditions. Complicated thermostatically controlled mixing valves have been introduced to overcome the temperature regulating problem but have lead to an increase in the cost and maintanence requirements of the installation. Knocking may occur on closing known mixing valves. Calcium deposits in hard water areas can interfere with the satisfactory functioning of the valves. The valves are difficult to install in a way so as to provide balanced flow.

It is an object of the invention to provide a mixing valve permitting good flow rates which is easy to install, maintain and operate.

Summary of invention According to the invention there is provided a mixing valve having a mixing chamber, blending valve means including a first valve having a valve member rotatable about an axis extending substantially at right angles to a passage leading to and from the valve for regulating flow of hot water to the chamber and a second valve having a valve member rotatable about an axis extending substantially at right angles to a passage leading to and from the second valve for controlling the flow of cold water to the chamber, each said valve having a spindle for controlling the angle of the valve members to the direction of flow through the passages, and regulating means acting on the respective spindles for opening and closing the first and second valves to varying extents so as to regulate the temperature of water flowing out of the mixing chamber.

The first and second valves may be butterfly valves for blending different proportions of hot and cold water so as to give a desired outflow temperature. The butterfly valves may each have a bore with a generally disc shaped valve member rotatably mounted therein. When the bores are small, as for mixing valves for shower installations, a pair of butterfly valves can give good blending control. The bores may have a diameter from 1/2" to 1", preferably 3/4" approximately. The bores have conveniently a substantially constant diameter and are straight.

The respective butterfly valves may be accommodated in separate valve bodies, one on each side of a valve body containing a mixing chamber and mounting an outflow control valve. This arrangement facilitates construction, installation and maintenance.

Advantageously the butterfly valve members each mount a sealing ring for engaging the bore and the sealing ring has apertures for a spindle for rotating the valve member. The sealing ring thus also seals off the interior of the bore from the holes containing the spindle. Advantageously, the valve members are each thin so as to provide only a small flow obstruction when in an open condition. Under appropriate conditions, each of the butterfly valves may have a dynamic flow range of between an 8% open and an 80% open condition in which range the amount of flow of water may increase gradually and controllably.

Preferably the valve member is cylindrical and has an aperture for aligning with the passage. Preferably a sealing ring is provided around the cylindrical valve member at locations spaced sideways with respect to the associated passage.

The arrangement provides a flow modulating valve with a low torque arrangement and a low internal pressure loss characteristic in addition to a good pressure loss characteristic in addition to a good linearity between the displacement of temperature regulating means and the consequential temperature changes obtainable. The arrangement can be constructed in a simple manner.

Preferably a flow control valve controls flow out of the mixing chamber, and a control means separate from the regulating means is provided for varying flow out of the mixing chamber.

The outflow control valve may have a valve member for engaging a valve seat formed at the end of a bore communicating with an outlet for mixed water and the valve member may be located on the end of a spindle outside the bore so as to be urged against the valve seat by the pressure of water in the mixing chamber. The various bores and the mixing chamber can be arranged so that the water flows with only small hindrance up to the outflow control valve seating and the outflow control valve can be used not only to vary the amount of water flow but also to increase the outflow velocity.

Suitably however a further chamber is provided for receiving the outflow of the mixing chamber which itself is connected to an outflow for mixed water and the flow control valve includes a spindle having a valve member for engaging a seat at the end of the mixing chamber downstream of the mixing chamber and the further chamber is an annular chamber surrounding the seat. The mixing can thus be effected with a swirling action with a large open area for mixing.

The valve members are conveniently turned in synchronism by a temperature regulating knob which may be controlled manually or automatically such as for example by a thermostatic control arrangement. Preferably the valve members each mount a gear such as a quadrant, meshing with a control gear conveniently turning about an axis coincident with that of the flow control valve spindle.

By using the gear control a flat and compact arrangement can be provided which does not greatly increase the mixing valve dimension and can be conveniently accommodated between the different bodies and a flow control valve knob. The gear control also enables the valve members to be interconnected by means of the control gear at different relative angular positions. Thus not only can the pair of valve members be connected in whichever sense to a hot and cold water supply with the gear control being set to increase the water temperature by turning the central gear in a particular sense but also the valve members spindles can be set so as to limit its closing to admit, say, cold water to the mixing chamber at all times. The range of outflow temperatures can be kept at a desired level even when the hot and cold water temperatures differ greatly and the risk scalding can be reduced.

It has been found very advantageous to throttle the flow of hot or cold water in the vicinity of the mixing chamber so as to obtain substantially equal flows from the hot and cold water supply. Preferably the valve member is close to the mixing chamber (i.e. at a distance of 4 to 6 times the butterfly valve bore diameter approximately) and the throttle valve is accommodated in elbows connecting the mixing valve to the hot and cold water supply so as to reduce the mixing chamber-throttle valve distance.

In this way the mixing valve continues to function satisfactorily even where the hot and cold water supply pressures differ greatly. The valve members, which do not unduly hinder flow themseleves, permit the effect of the throttling of the flow to be communicated to the mixing chamber and promote balanced blending in the mixing chamber, which may be small.

By positioning the valve members close to the flow control valve spindle, the area taken up by the flat gear arrangement can be kept quite small and a compact mixing valve can be produced. The central gear can be arranged to move the valve members angularly through 90" at a gear transmission ratio of at least one and conveniently 2:1 so that the valve members can be adjusted easily and sensitively.

Using the mixing valve of the invention good flows may be obtained from the mixing valve even under low pressure supply conditions. By appropriate setting of throttle valves ease of temperature regulation can be maintained at the same time as good flow whilst the supply conditions of hot and cold water respectively differ. The mixing valve provides a sensitive, graduated response when blending hot and cold water, in minimising undesired sudden temperature changes. A shower arrangement can be produced which increases or maintains sensitivity of temperature adjustment whilst being indifferent or less sensitive to variations in plumbing conditions externally of the mixing valve. The valve members are largely self-cleaning and their operation is little effected by calcium deposits.Sealing difficulties involving the valve members are unlikely to materially affect operation as valve members serve to blend only and outflow is shut off by the flow control valve.

Using preferred forms of the invention, an effective yet simple mixing valve can be produced. Only a single valve body can be used to mount both temperature and flow regulating valves. The mixing valve can be simply asembled and adjusted before use, especially if the spindles are rotated simultaneously by means of gear sectors and sandwiched between components of a control knob arrangement.

Whilst the throttle valve is particularly useful in conjunction with the butterfly valves it can be used in conjunction with known temperature regulating valve means to improve their performance.

Drawings Figure 1 shows a front elevation of a mixer valve of the invention; Figure 2 shows a section along line ll-ll in Figure 1; Figure3shows a section along line Ill-Ill in Figure 2; and Figure 4 shows a section through a mixing valve having cylindrical cock-valves and according to the invention.

Construction ofpreferred embodiments With reference to Figures 1 to 3, a mixing valve 1 has a mixing chamber 2 in a main valve body 4. An outflow control valve 6 is located inside the chamber 2. Butterfly valves 8 for blending hot and cold water in the appropriate proportions to regulate the outflow temperature are mounted in blending valve housings 10 attached by screws and spindles to the main valve body 4. Each of the two butterfly valves is preferably of the type described in the British Patent Specification 1,421,700 and has a valve member 11 consisting of a pair of plates 12 and a sealing ring 14 held between the edges of the plates 12. The ring 14 has holes diametrically opposite one another for receiving a spindle 16 of the butterflyvalve 8.The spindle 16 extends through the ring 14, between the plates 12 and is located in holes in the blending valve housing 10. The ring 14 thus seals the valve member 11 and the spindle 16. A throttle valve 20 is screwed onto each of the blending valve housings 10 (but is not shown in Figure 3).

As regards the main valve body 4, this includes a bottom cover 22, a part annular mixing chamber body 24 and a top cover united by screws into a single unit. The bottom cover 22 has a dovetailed projection for sliding into a corresponding slot in a mounting bracket 28 for fastening to a wall. The outflow control valve 6 has a spindle 30 screwed into the bottom cover 22 and extending through a slot in the top cover 26 so as to hold the spindle 30 against rotation. A sleeve 32 is screwed onto the spindle 30 and has a valve member 34 with an O-ring 36 at the bottom end and is keyed at the top to an outflow control knob 39 with a domed cap 40.Turning of the knob 39 lowers or raises the valve member 34 thus bringing it out of or into sealing engagement with respect to a surface on an inner cylindrical projection 38 surrounding the sleeve 32 and extending partly into the mixing chamber 2.

A radial bore 42 extends through the main valve body 4through to the space formed between the sleeve 32 and the projection 38 for water flowing out of the mixing valve 1. Bores 50 extend through the blending valve housings 10 in a straight line through to the mixing chamber 2 for supplying hot and cold water.

The spindles 16 extend to above the top cover 26.

Atemperature regulating knob 44 is retained between the knob 38 and the top cover 26 and carries a spur gear 46. The knob 44 and the top cover 26 also sandwich between them quadrant gears 48 in mesh with the spur gear 46 and keyed to the upper ends of the spindles 16.

The throttle valves 20 are L-shaped. A first passage in the valves is aligned and coupled to a plumbing pipe for hot or cold water (not shown). A second passage is aligned with the bores 50. One of the passages contains a balancing spool or valve body 52 whose angular position can be adjusted from the outside by means of screwdriver or spanner. The spool 52 has an aperture 54 of a cross-section substantially equal to that of the other passage. By turning the spoot 52 the flow through the valve 20 can be throttle to varying extents.

If required a wall mounted cover 47 is provided to screen the plumbing connection from view. O-rings 55 provide seals between the respective components where required.

Installation The bracket 28 is first secured to the wall. The mixing valve 1 proper is then slid into position for connection by hexagonal nuts (as shown at 56 in Figure 2) to the plumbing system. After connection, the knob 44 and quadrant gears 48 are so fitted that turning of the knob 44 in the required sense, say by way of example clockwise, opens the butterfly valve 8 regulating the hot water supply and closes the valve 8 for the cold water supply. Figure 1 (and the corresponding Figure 3) show the arrangement with the knob 44 on "cold" where hot water is supplied through the bore 50 on the left. Turning of the knob 44 through 1800 will completely open the butterfly valve on the left and close that on the right giving hot water only.If it turns out that the cold water supply pipe is on the left instead, the knob 44 can be lifted off after undoing securing nuts 58 (see Figure 2) to free the quadrant gears 48. The spindles 16 can then be turned through 90" and keyed back to the quadrant gears 48. After re-fastening the knob 44, it will gradually increase the proportion of hot water on turning it clockwise.

Where the hot water temperature is very high (for example where a back boiler is used), the spindles 16 can be set to place the valve members 11 at a relative angle of other than 90". For example, the valve member 11 for cold water can be set in a partly open position when the spindle for the hot water valve member is fully open. When the quadrant gears 48 are then meshed with the spur gear 46 and turned by the knob 44 the range of movement will be less than before and further movement prevented when the spindle for the cold water valve member reaches the fully open position at which time the hot water valve member will only be partly closed. However the outflow will at all times contain cold water so reducing the risk of scalding.Alternatively the valve member 11 for cold water can be set in a fully closed position when the valve member for hot water is partly open. Thus the flow of hot water into the mixing chamber 2 is limited. Movement of the valve members 11 past the fully open or fully closed position can be prevented by suitably placed abutments acting on the quadrant geawr 48 or spindle 16.

Having now properly connected the valve 1 and set the quadrant gears 48, a plumber then adjusts the throttle valves 20 until water emerges in the fully "hot" condition of the knob 44 at the same rate as water emerges in the fully "cold" position. The amount of water emerging can be adjusted by turning the spool 52 to give a desired flow rate overall. A protective cap 60 can be then secured over the spool 52.

The mixing valve can now be used to provide a sensitive temperature regulation, even if the pressures of hot and cold water supplied differ greatly, and to provide a satisfactory flow of water.

With reference to Figure 4, the valve is generally similar to that described with reference to Figures 1to 3. Analogous components have the same reference numerals. An integral main valve body 4 has a transverse bore and a plurality of inward bores at right angles to the transverse bore for receiving different valve components. An outflow control valve 6 extends through a middle inward bore 2 and controls flow into an annular chamber 3. The bore 2 receives both hot and cold water from the transverse bore. Cylindrical cock or spool valves 8 have valve members 11 which are mounted in inward bores 10 and have a pair of sealing rings 14. The valves members 11 have a passage of a diameter the same as the transverse bore so as to pass water in a fully open condition without any additional flow restriction. The members 11 are formed with a spindle 16 extending outwards of the body 4.A throttle valve 20 may be attached to the body upstream of each of the valves 8 to balance the hot and cold water flows.

The valve body 4 may be wall-mounted as described with reference to Figures 1 to 3 using a bottom cover 22 and wall mounting bracket.

The outflow valve 6 consists of a spindle 30 fastened at the top to a plastics outflow control knob 39. The spindle 30 is screwed into the body 4at 41 and has a wide diameter portion 34 with an O-ring.

Turning of the knob 39 can lift the O-ring and enable water to flow from the middle bore 2 to the annular chamber 3. As shown in dotted lines the chamber has an opening leading to a bore 42 for the removal of mixed water.

The spindles 16 extend to above a top cover 26 which has a raised cylindrical part 27 surrounding the sprindle 30. The spindles 16 are keyed to quadrant gears 48 in mesh with a spur gear 46 of a temperature regulating knob 44 sandwiched between the knob 39 and the quadrant gears 48. It is also possible to use cylindrical bodies 8 having recesses in their sides instead of a diametrical passage. Other forms of valves could also be used especially if the valves have a low torque characteristic and impose only a low pressure loss. In this way the valve blending characteristics can be varied.

The travel of the quadrant gears 48 and the knob 44 is limited as follows. The knob 39 has a rib 62 for engaging a facing abutment on the knob 44. This ensures that, when the knob 39 has been turned to the fully closed position preventing any outflow, the knob 44 has been turned so as to fully close the flow of hot water through the appropriate valve 8 and open the cold water valve 8. Thus when the valve is used subsequently, the initial flow will be of cold water and the hot water cannot penetrate into the cold water system when the mixing valve is not in use. The lower inner edge of the knob 44 engages the quadrant gears 48 when the hot water valve 8 is fully open to prevent any-further movement.

The throttle valve 20 has a needle element as the valve body 52, which can be adjusted from the outside to vary or blockthe flow. Thus the mixing valve can be repaired conveniently afterthe throttle valves have been closed.

Claims

1. A mixing valve having a mixing chamber, blending valve means including a first valve having a valve member rotatable about an axis extending substantially at right angles to a passage leading to and from the valve for regulating flow of hot water to the chamber and a second valve having a valve member rotatable about an axis extending substantially at right angles to a passage leading to and from the second valve for controlling the flow of cold water to the chamber, each said valve having a spindle for controlling the angle of the valve members to the direction of flow through the passages, and regulating means acting on the respective spindles for opening and closing the first and second valves to varying extents so as to regulate the temperature of water flowing out of the mixing chamber,

2.A mixing valve according to claim 1 in which the valve member is cylindrical and has an aperture for aligning with the passage.

3. A mixing valve according to claim 2 in which a sealing ring is provided around the cylindrical valve member at locations spaced sideways with respect to the associated passage.

4. A mixing valve according to claim 1 in which the valve member is generally flat and is mounted on a spindle so as to provide a butterfly type valve.

5. A mixing valve according to any of claims 1 to 4 in which the flow control valve controls flow out of the mixing chamber and a control means separate from the regulating means is provided for varying the flow out of the mixing chamber.

6. A mixing valve according to claim 5 in which the flow control valve has a valve member for engaging a seat at the end of a bore communicating with an outlet for water and the valve member is located on the end of a spindle and is outside the bore so as to be urged toward the valve seat by water in the mixing chamber.

7. A mixing valve according to claim 5 in which a further chamber is provided for receiving the outflow of the mixing chamber which itself is connected to an outflow for mixed water.

8. A mixing valve according to claim 7 in which the flow control valve includes a spindle having a valve member for engaging a seat at the end of the mixing chamber downstream of the mixing chamber and the further chamber is an annular chamber surrounding the seat.

9. A mixing valve according to any of claims 5 to 8 in which the flow control means and the regulating means are arranged so that with the outflow closed, the regulating means closes the hot water regulating valve.

10. A mixing valve according to any of the preceding claims in which the regulating means includes a first gear operable manually, second and third gears turnable conjointly with the respective valve members and both meshing with the first gear so that by turning the first gear the respective butterfly valves open and close for blending different proportions of hot and cold water.

11. A mixing valve according to any of the preceding claims in which an adjustable throttle valve is associated with at least one of the butterfly valves so that supply conditions of the hot and cold water respectively can be balanced.

12. A mixing valve according to claim 11 in which the throttle valve is capable of being closed to isolate the mixing valve from the hot and/or cold water supply.

13. A mixing valve having a mixing chamber, blending valve means for regulating flow of hot water to the chamber and blending valve means for regulating flow of cold water to the chamber and a throttle valve associated with at least one of the blending valve means for balancing flows of hot and cold water to the mixing chamber.

14. A mixing valve according to claim 13 which is capable of being closed to isolate the mixing valve from the hot and cold water supply.

15. A mixing valve substantially as described with reference to and as shown in Figures 1 to 3.

16. A mixing valve substantially as described with reference to and as shown in Figure 4.

17. A mixing valve having a mixing chamber, blending valve means includung a butterfly valve for regulating flow of hot water to the chamber and a butterfly valve for regulating flow of cold water to the chamber, each said butterfly valve having a valve member for regulating flow and a spindle for controlling the angle of the valve members to the direction of flow, and regulating means acting on the respective spindles for opening and closing the butterfly valves to varying extents so as to regulate the temperature of water flowing out of the mixing chamber.