GB2041167A - Valves - Google Patents

Abstract

A shower mixture tap, including a pressure responsive flow control device for regulating the cold water feed for mixing with a hot water supply, comprises a valve assembly movable between an off position in which a washer 33 abuts a seating 42, and a maximum flow position in which the flow passes between a fluted portion 43 of the valve assembly and an O-ring 35, via an intermediate closed position in which the O-ring 35 engages a cylindrical portion of the valve assembly to prevent the flow. The cross-sectional area of the fluted portion 43 varies along its length so that the rate of flow can be adjusted by moving the valve assembly. The O-ring 35 is responsive to supply pressure to compensate for pressure variations. The valve assembly incorporates a jumper pin 31 movable by a spindle 36 located by a gland 37 of the tap. <IMAGE>

Description

SPECIFICATION Improvements in or relating to liquid flow control devices There are many devices which are designed to minimise or reduce the effects of variations in supply pressure of a liquid in order to give a constant or nearly constant flow of liquid.

Such known devices are often in the form of pressure regulators which are complex, expensive, require calibration or setting during manufacture and are not normally suitable for use in domestic water applicances such as electrically heated showers. Devices in the form of flow regulators are known, in which devices a resilient member is disposed so as to deform progressively with increasing supply pressure to restrict a flow passage or passages within the device, but the flow through the device will remain constant only if there is no or a constant back pressure acting on the flow from the device. Such flow control regulators can sometimes be made to be controllable by arranging for the relative positions of the resilient member and the passage to be adjustable.Attempts have been made to utilise such controllable flow regulators in shower apparatus, but such attempts have revealed the difficulty of providing a constant back pressure, owing to presence of stop valves or taps in the apparatus, without requiring considerable skill and the constant attention of the user of the apparatus.

What is needed is an improved form of liquid flow control device which is simple to use, is effective in providing a controlled rate of flow, and is relatively simple and inexpensive to manufacture.

According to the present invention there is provided a liquid flow control device which comprises an inlet and an outlet, an internally open seating means between said inlet and outlet, a valve assembly projecting into said seating means to define a flow path therebetween, and a hollow flow control member located in said flow path by a first seating of said seating means; wherein the seating means provides a second seating between the first seating and the outlet; the valve assembly comprises a peripherally fluted portion, an annular resilient shoulder, and a cylindrical portion between and co-axial with said fluted portion and said shoulder on a central axis of the valve assembly; the fluted portion decreases in cross sectional area normal to said axis from a maximum cross sectional area adjacent the cylindrical portion; the valve assembly is arranged to be movable by actuating means along said axis, between a closed position, wherein the shoulder is clamped against the second seating to seal the flow path, and a maximum flow position, in which the flow control member lies around a part of the fluted portion remote from the cylindrical portion, via an intermediate position in which the shoulder is spaced apart from the second seating to open the flow path to the outlet, and in which the cylindrical portion engages the flow control member substantially to block said flow path, and via further positions in which the fluted portion is disposed so that the flow control member lies around the fluted portion to restrict the flow path; and wherein the flow control member is resiliently deformable and is adapted to co-operate with said fluted portion, when disposed around the latter, whereby to be responsive to inlet pressure to vary the restriction of the flow path in response to variations in the inlet pressure.

The cross sectional area of the fluted portion preferably reaches a minimum at an end of the valve assembly, and in said maximum flow position this said end and flow control member preferably both lie in a plane perpendiculr to the central axis.

The actuating means is preferably similar in form to those employed in domestic water taps which comprise a spindle to raise and lower a jumper, having a seating washer, off and onto seating, and the valve assembly preferably includes a central pin which serves as a jumper to engage in the spindle. The invention includes a tap incorporating the liquid flow control device of the invention.

The invention also includes a water flow control assembly which incorporates the liquid flow control device of the invention so as to control a cold water feed for mixing with, and moderating the temperature of, a hot water supply for shower apparatus.

The water flow control assembly may further comprise a non-adjustable liquid flow control device for controlling a supply a cold water to a water heater, which device comprises an inlet, an outlet, a passage connecting the inlet and outlet, and, in said passage, a throttle and a variable restrictor; wherein said throttle comprises a fixed port surrounded by a rigid abutment face which confronts the variable restrictor; wherein said variable restrictor comprises a flexible resilient member having an aperture therein, which aperture is aligned with the fixed port and interrupts a concave or recessed face which confronts the abutment face; and wherein the resilient member is disposed between the throttle and the inlet.

The invention further includes water heating apparatus provided with the water flow cor.- trol assembly.

The invention will be described further, by way of example, with reference to the accompanying drawings, wherein: Figure 1 shows a vertical cross section through a water flow control assembly of the invention, so as to show a non-adjustable flow control device; Figure 2 shows a longitudinal cross section through said assembly, so as to show an adjustable liquid flow control device of the present invention; and Figure 3 shows an enlarged cross section of a fluted portion of a valve assembly of the device shown in Fig. 2.

Referring to Figs. 1 and 2, the assembly has a cast metal body 10, which is provided with a water inlet 11, a heater supply passage 1 2 which extends from the inlet 11 to a heater supply outlet 1 3 via a heater supply tap 14 (indicated in broken lines), a heater return passage 1 5 which extends from a heater return inlet (not shown) to a shower supply outlet 1 6 via an outlet chamber 1 7 of a cooling water tap 18, and a cooling water inlet passage 1 9 which is connected to the outlet 1 6 as hereinafter described.

Referring to Fig. 1, the heater supply outlet 1 3 is defined by a metal fitting 20 which incorporates a throttle 21 of the non-adjustable liquid flow control device. The throttle 21 has a planar abutment face 22, provided by.

an end of the fitting, which face surrounds a fixed circular port 23 which extends through the end of the fitting to the supply outlet 1 3.

The non-adjustable liquid flow control device includes a variable restrictor member 24 which has recessed face 26 surrounding a circular aperture 25 which extends through the restrictor and is in axial alignment with the port 23. The peripheral portion of the face 26 is perpendicular to the axis of the aperture 25 and surrounds a part conical inner portion which is inclined to the axis so that the thickness of the restrictor member 24 adjacent the aperture is only about half of its peripheral thickness of about 4mm. The variable restrictor member 24 is moulded from a resilient flexible polymeric material which is resistant to the chemicals found in mains water supplies and is stable in cold and warm water.

In use, the inlet 11 is connected to a mains water supply, the outlet 1 3 is connected to the inlet of an instantaneous water heater, such as an "Alflow" 7000 water heater ("Aflow" is a Registered Trade Mark of the Applicants), and the heater outlet is connected to the passage 1 5 by the return inlet. When the tap 14 is turned on water flows from the mains to the outlet 1 6 via the liquid flow control device and the heater.

In this embodiment, the nominal normal diameter of the aperture 25 is about 3mm and the diameter of the port 23 is about 3mm, whereby to give a resistance to the flow of water which is slightly greater than the resistance to flow presented by the heater at the minimum rate of flow necessary for operation of the heater.

The liquid flow control device functions to keep the flow of water substantially constant at a rate predetermined to suit the heater, irrespective of mains supply pressure variations within a range of about 20 pounds per square inch up to at least 80 pounds per square inch, the member 24 deforming progressively with increase in the pressure differential applied thereto so as to reduce the effective diameter of the aperture up to the limit wherein the inner portion of the fact 26 abuts the abutment face 22.

As the non-adjustable liquid flow control device provides a substantially constant rate of flow to the water heater, the temperature of the water flow in the return passage 1 5 will be proportional to the heaters thermal output and the water supply temperature, and may need to be moderated.

The tap 1 8 is of known kind, and simply functions to admit water from the passage 1 9 into the chamber 1 7 to mix with the hot water, at a rate which depends upon the tap opening and the water supply pressure.

In the embodiment shown in Figs. 2 and 3 the tap 1 8 is provided with the adjustable flow control device. This device comprises seating means in the form of a metal insert 30 press fitted into the body 10 to extend between the inlet passage 1 9 and the outlet chamber 17; a valve assembly in the form of a pin 31 having located thereon a metal washer 32, a resilient washer 33 and a hard plastics moulding 34; and a flow control member in the form of a resilient "O"-ring 35. The pin 31 is inserted into a spindle 36 of the tap so that the spindle 36 serves as actuating means to move the device along the axis of the tap. The tap has a gland 37, packing 38 and gland nut 39 of known form and function.

The valve assembly extends into the insert 30 to define therebetween a flow path 40 from an inlet end to an outlet end of the insert 30.

The insert 30 is chamfered at the inlet end to trap a sealing ring 41 against the body, has a first seating in which the O-ring 35 is located, and has a second seating 42 perpendicular to the tap axis at the outlet end.

The washer 33 provides an annular resilient shoulder which is arranged to abut and make a seal with the seating 42 to shut off the flow path 40 when the tap is in a turned off position.

The moulding 34 comprises a cylindrical portion which is a close fit in the O-ring 35, and a fluted portion 43 (Fig. 3) which tapers so as to decrease in cross sectional area from a maximum adjacent the cylindrical portion.

The flutes 44 are rounded, extend longitudinally of the portion 43, and decreases in radial depth towards the cylindrical portion.

In use, as the tap is turned on initially the cylindrical portion slides within the O-ring 35, as the washer 33 is moved off and away from the seating 42, so that the O-ring substantially blocks the flow path 40 until, in an intermediate position, the washer 33 is spaced apart from the seating 42 so as not to obstruct the connection between the flow path 40 and the outlet chamber 1 7.

As the tap is turned on beyond the intermediate position, the fluted portion 43 enters the O-ring 35 to enable water to flow between the flutes 44 and the O-ring 35. In the absence of any water inlet pressure, the effective cross sectional area of the flow path 40, i.e. the area between the flutes 44 and the O-ring 35, increases from a minimum when the maximum cross sectional area of the portion 43 lies within the O-ring 35, to a maximum when the minimum cross sectional area of the portion 43 lies within the O-ring, so that said effective cross sectional area increases as the tap is turned on further up to a predetermined maximum flow position wherein the washer 32 abuts the gland 37 to limit the movement of the flow control device.

The O-ring 35 is made from an elastomeric material which is sufficiently resilient to allow the O-ring to deform under pressure to an extent which allows the O-ring to conform progressively to and to constrict progressively against the periphery of the fluted portion to decrease said effective cross sectional area as the water supply pressure increases; and which is sufficiently stiff to restrict said decrease to an amount which substantially negates the effect of the pressure increase on the rate of flow of water through the flow path.

For domestic use, the adjustable flow control device can be constructed to maintain a selected rate of flow at a substantially constant value over a range of water supply pressure from about 20 to 80 pounds per square inch.

The invention is not confined to the precise details of the foregoing example. For instance, the adjustable flow control device can be incorporated into a domestic tap which can be of known construction except for the provision of said device and an enlarged inlet bore to accept or serve as the seating means; and two such taps may be combined in a mixer tap unit to control hot and cold water supplies to give an adjustable output having a selected substantially constant flow rate and temperature.

In use, such taps incorporating said adjustable device are so simple to operate that the person operating the taps may be unaware of the presence of the device. Furthermore, the working life of the O-ring 35 is very long, due to various factors not least of which are the supporting of the O-ring in an undeformed state by the cylindrical portion when the tap is closed, and the provision of a separate seal which is effective when the tap is closed to substantially prevent sustained pressure differentials across the O-ring.

Claims (11)

1. A liquid flow control device comprising an inlet and an outlet, an internally open seating means between said inlet and outlet, a valve assembly projecting into said seating means to define a flow path therebetween, and a hollow flow control member located in said flow path by a first seating of said seating means; wherein the seating means provides a second seating between the first seating and the outlet; the valve assembly comprises a peripherally fluted portion, an annular resilient shoulder, and a cylindrical portion between and co-axial with said fluted portion and said shoulder on a central axis of the valve assembly; the fluted portion de creases in cross sectional area normal to said axis from a maximum cross sectional area adjacent the cylindrical portion; the valve as sembly is arranged to be movable by actuat ing means along said axis, between a closed position, wherein the shoulder is clamped against the second seating to seal the flow path, and a maximum flow position, in which the flow control member lies around a part of the fluted portion remote from the cylindrical portion, via an intermediate position in which the shoulder is spaced apart from the second seating to open the flow path to the outlet, and in which the cylindrial portion engages the flow control member substantially to block said flow path, and via further positions in which the fluted portion is disposed so that the flow control member lies around the fluted portion to restrict the flow path; and wherein the flow control member is resiliently deforma ble and is adapted to co-operate with said fluted portion, when disposed around the lat ter, whereby to be responsive to inlet pressure to vary the restriction of the flow path in response to variations in the inlet pressure.

2. A device as claimed in claim 1, wherein the valve assembly comprises a pin, together with a resilient washer and a hard plastics moulding located on said pin so that the resilient washer provides said resilient shoul der and the moudling provides said cylindrical and fluted portions.

3. A device as claimed in claim 2, wherein the pin serves as a jumper and engages in a spindle of the actuating means, and wherein a metal washer is interposed between said resil ient washer and an end of the spindle.

4. A liquid flow control device substan tially as herein before described with reference to Fig. 2 or Figs. 2 and 3 of the accompanying drawings.

5. A tap comprising a liquid flow control device as claimed in any preceding claim.

6. A tap as claimed in claim 5, wherein the actuating means comprises a gland dis posed to abut the valve assembly when the latter is disposed in said maximum flow posi tion.

7. A tap as claimed in claim 5 or 6, wherein the seating means comprises a flanged metal insert fitted into a body of the tap.

8. A tap substantially as hereinbefore described with reference to Fig. 2 or Figs. 2 and 3 of the accompanying drawings.

9. A water flow control assembly comprising a tap as claimed in any one of claims 5 to 8 wherein the tap is arranged in said assembly to control a cold water feed for mixing in said assembly with a hot water supply.

10. A water flow control assembly as claimed in claim 9, further comprising a nonadjustable water flow control device, which is adapted to control a supply of cold water to a heater for providing said hot water supply, and which comprises an inlet, an outlet, a passage connecting the inlet and outlet, and, in said passage, a throttle and a variable restrictor; wherein said throttle comprises a fixed port surrounded by a rigid abutment face which confronts the variable restrictor; wherein said variable restrictor comprises a flexible resilient member having an aperture face which confronts the variable restrictor; wherein said variable restrictor comprises a flexible resilient member having an aperture face; and wherein the resilient member is disposed between the throttle and the inlet.

11. A water flow control assembly substantially as hereinbefore described with reference to the accompanying drawings.

1 2. Water heating apparatus, for a shower, comprising a water heater and a water flow control assembly as claimed in claim 9, 10 or 11.