GB2049884A

GB2049884A - Fluid flow regulator

Info

Publication number: GB2049884A
Application number: GB8014276A
Authority: GB
Original assignee: Redring Electric Ltd
Current assignee: Redring Electric Ltd
Priority date: 1979-05-10
Filing date: 1980-04-30
Publication date: 1980-12-31
Also published as: GB2049884B

Abstract

An in-line fluid flow regulator has an opening (6) for the passage of fluid between its inlet and outlet, and a control member (12) supported coaxially with respect to the opening and surrounded by an elastically deformable ring (11) which tends to deform by varying amounts with changes of inlet pressure so as to vary the flow path or paths through the opening in a sense which tends to maintain the flow approximately at a set value, and means (15) for manually adjusting the position of the control member with respect to the opening to enable the set rate of flow to be varied. The flow regulator is particularly suitable for use with instantaneous electric water heaters, more especially for shower units. <IMAGE>

Description

SPECIFICATION Fluid flow regulators This invention relates to fluid flow regulators, and is especially, though not exclusively, concerned with regulators for controlling the flow of water through instantaneous electric water heaters as may be employed, for example, in shower units.

One difficulty which is often experienced with instantaneous water heaters, is that variations in the inlet water pressure tend to produce changes in the rate of flow of water through the heater, which causes the temperature of the water issuing from the heater to fluctuate, sometimes considerably. This is clearly a disadvantage, particularly in the case of heaters employed in shower units, and an object of the invention is to provide a form of flow regulator capable of suppressing fluctuations in the rate of flow of a fluid resulting from pressure variations. A further object of the invention is to provide a regulator suitable for use with a shower water heater, and which enables the rate of flow to be readily adjusted.

According to the invention a fluid flow regulator comprises a substantially straight tubular body whose ends are arranged to be connected to cooperating inlet and outlet pipes, and which incorporates a partition separating the interior of the housing into an inlet and an outlet compartment, the partition being provided with an opening which interconnects the compartments and being arranged so that the axis of the opening extends generally transverse to the body axis, a control member supported coaxially with respect to the opening, and an elastically deformable ring around the control member, the arrangement being such that the ring tends to deform due to the difference in pressures of the fluid in the inlet and outlet compartments and results in a change in cross-section of the flow path or paths through the opening in the sense which tends to maintain the rate of flow of fluid through the regulator approximately at a set value, and means for manually adjusting the position of the control member along the axis of the opening whereby the set rate of flow can be varied.

By making the regulator body of straight tubular form, and providing it with standard means for coupling its ends to the inlet outlet pipes it can readily be fitted as an in-line regulator into a fluid flow system, for example into the inlet pipe system of an instantaneous water heater, in a similar manner to known forms of manual control valves.

The control member is conveniently carried by a threaded spindle screwed into a threaded sleeve supported by the body coaxial with the said opening, so that rotation of the spindle with respect to the sleeve produces an axial movement of the control member relative to the opening. The spindle conveniently terminates outside the housing in a suitable manually adjustable control knob.

5 The axis of the opening, and consequently that of the spindle, may be at right angles to the body axis, or may be inclined to it as in the case of standard forms of manually operated fluid control valves.

In one regulator in accordance with the invention at least the part of the surface of the control member which co-operates with the ring may be approximately of truncated conical shape narrower at the upstream end and axially movable within said opening, the elastically deformable ring being supported by the conical surface of the control member, such that as the pressure of fluid in the inlet compartment increases the ring is forced towards the larger end of the control member, thereby restricting the flow path through the opening, and when the pressure of fluid in the inlet compartment decreases the ring moves towards the narrower end of the control member, thereby increasing the flow path through the opening, the shape of the opening being such that varying the axial position of the member relative to the opening varies the rate of flow for a given difference between the inlet and outlet pressures.

Preferably the opening is of truncated conical shape narrower at the downstream end, or is formed with one or more longitudinally extending grooves having a cross-section which diminishes towards the downstream end.

In an alternative arrangement at least the part of the surface of the control member which co operates with the ring is of approximately cylindrical shape provided with one or more grooves extending along it and providing a flow path or paths for the fluid between the control member and the ring, the depth of the groove or grooves varying along the length of the member, the ring being supported against any substantial axial movement with respect to the opening, and the arrangement being such that in use of the regulator the pressure of fluid in the inlet chamber urges the ring into the groove or grooves by an amount which increases with increasing pressure, thereby reducing the cross-section of the fluid flow path or paths by an amount which tends to maintain the fluid flow at said set value.Then by moving the control member axially relative to the ring the flow rate can be adjusted.

The groove or grooves need not lie parallel to the axis but may in some cases be inlined to it.

Preferably the control member has a plurality of grooves separated by intervening ribs the outer surfaces of the ribs being rounded so that they merge smoothly into the grooves.

Three embodiments of the invention will now be described by way of example with reference to Figures 1 to 6 of the accompanying drawings, in which Figure 1 represents diagrammatically, and not to scale, an axial cross-section of a fluid flow regulator in accordance with the invention suitable for maintaining the flow of fluid through an instantaneous electric water heater substantially at a set value despite changes in water pressure, Figure 2 represents an enlarged cross section of the operative parts of the regulator adjusted for maximum rate of flow, Figure 3 shows a similar view of the operative parts of the regulator adjusted for minimum rate of flow, Figure 4 is a part sectional plan view of the main elements of the part of the regulator shown in Figures 2 and 3, Figure 5 is an axial cross-section of part of a second form of fluid flow regulator, and Figure 6 is an axial section of another form of regulator.

Referring first to Figure 1, the regulator comprises a short tubular body 1 internally threaded at each end for connection to inlet and outlet pipes at 2 and 3 respectively. The body 1 has an internal partition 4 dividing the interior interior into inlet and outlet compartments 2.1 and 3.1,the partition having aflatsection 5 lying generally parallel to the body axis and containing a circular opening 6. The part of the wall of the body opposite this opening 6 is also formed with a further opening surrounded by a cylindrical, internally-threaded, flange 7.

Into this flange is screwed a sleeve 8 which clamps an annular regulator housing 9 to the flat section 5 of the partition, the regulator housing supporting within it an elastically deformable ring 1 1., formed, for example, of rubber or suitable synthetic plastics material. Within the regulator housing 9 and ring 11 there is located a control member 12 of generally cylindrical shape having a series of longitudinal grooves 13, separated by intervening ribs 14 and having a depth which decreases towards the lower end of the member as shown more clearly in Figures 2 to 4.

The control member 12 is carried by the lower end of a spindle 15 which projects outwards from the opening in the body 1, the member being secured to the spindle by a nut 1 6 but being free to rotate on the spindle 1 5.

The spindle is rotationally supported within a headwork nut 1 7 similar to that employed in a standard control valve screwed into the internallythreaded upper part of the sleeve 8.

The outer end of the headwork nut 1 7 contains a packing gland 1 8 which surrounds the spindle 1 5 and is compressed onto it by a gland nut 19, which can also be of standard form. To prevent leakage of water between the sleeve 8 and the headwork nut 17, a compression nut 21 is screwed on to the externally threaded upper part of the sleeve 8, a sealing washer 20 being clamped between the edge of the compression unit 21 and the edge of the cylindrical flange 7 around the opening in the body 1, a further sealing washer 22 being clamped between the headwork nut 1 7 and the top of the compression nut 21.

The spindle 1 5 carries an external thread which screws into the internally threaded headwork nut 1 7 so that rotation of the spindle by means of a knob 23 secured to its outer end, causes the control member 12 to move axially with respect to the housing 9 and hence the ring 11.

In use of the regulator water passes from the inlet compartment 2.1 into the sleeve 8 through the grooves 13 of the control member 12, ports 24 of any convenient shape being provided in the sleeve to permit the water to flow into the outlet compartment 3.1. The ring 11 is urged into the grooves 13 by an amount depending upon the difference in the pressures of water in the inlet and outlet compartments, which restricts the passage of water, the shape of the grooves and the material of the ring being such that the rate of flow of water is substantially constant for a given setting of the control member 12.Thus if the member is in its lowermost position shown in Figure 2, obtained by screwing the spindle 1 5 inwards, the distance between the ring and the bottom of the grooves 13 is at a maximum, for a given pressure difference between the inlet and outlet compartments, this giving the greatest rate of flow, whereas if the spindie is screwed outwards to its fullest extent, the control member will be in its highest position as shown in Figure 3, this giving the smallest rate of flow.

A separate onloff control valve in series with the regulator enables the water to bs turned on or off so that once adjusted to give a desired rate of flow the regulator can be left in its set position, and need only be altered when a different flow rate is required.

It has been found that an arrangement as above described is easily installed and for a given setting is capable of maintaining a substantially constant flow rate regardless of pressure variations in the mains water supply within the range 10 to 1 cho p.s.i.

An alternative form of regulator is illustrated in Figure 5.

This regulator also comprises a short tubular body (not shown) partitioned in a similar manner to that previously described and similarly provided with a sleeve 8. In this case the internal surface of the lower end of the sleeve 8 is of frusto-conical shape having its wider end downwards so that it faces the incoming water. A frusto-conical control member 26 is supported coaxially within the opening 27 in the flange on a spindle 28, with its narrower end downwards and carries around it an elastically deformable ring 29, the spindle itself being supported in the same manner as in the previous embodiment.

In use of the regulator the difference in pressures of water whin the inlet and outlet compartments causes the ring 29 to be urged towards the larger end of the control member 26 and hence towards the narrower end of the frustoconical opening 27, which restricts the passage of water through the regulator. The control member 26 and ring 29 are such that the rate of flow of water for a given setting of the control member is maintained substantially constant despite variations of inlet pressure as in the first embodiment Downward movement of the control member 26, resulting from a screwing in of the spindle 28 has the effect of increasing the rate of flow due to the shape of the opening 27, and upward movement of the control member reduces the rate of flow.

Instead of the opening being of frusto-conical shape it may alternatively be of approximately cylindrical shape with one or more grooves extending along it having a depth witb decreases towards the downstream end, which provides a similar variation in the flow rate as the position of the control member 26 is adjusted.

Figure 6 illustrates a modification of the regulator shown in Figures 1 to 4, and similarly comprises a tubular body 1 threaded at each end, this time externally and having an internal partition 4 dividing the interior into inlet and outlet compartments 2.1, 3.1, and containing a circular opening 6. A part of the wall of the body opposite this opening 6, is also formed with an opening surrounded by an internally-threaded tubular flange 7. Into the outer end of this flange 7 is screwed a spindle housing 30, accommodating a spindle 1 5 together with suitable packing glands (not shown), the outer end of the spindle carrying a control knob 31. The inner end of the spindle carries a control member 12 similar in shape to that illustrated in Figures 1 to 4, freely rotatable with respect to the spindle and secured to it by nuts 1 6.

The face of the partition 4 around the opening 6 forms a seating for an annular regulator housing 9 containing an elastically deformable ring 11, and clamped in position by an annular plate 32 screwed into the flange 7, a sealing gland 33 surrounding the housing 9. Adjustment of the control knob 31 varies the position of the control member 12 relative to the ring 11 and the regulator operates in the same manner as that described with reference to Figures 1 to 4, to maintain a constant rate of flow, determined by the setting of the control knob despite variations in inlet water pressure.

Other constructions of regulator can alternatively be employed. For example, instead of being held by a separate housing, the deformable ring may be accommodated in an annular groove formed in a part of the regulator body surrounding the control member 12.

It-wili be understood that the invention includes within its scope instantaneous electric water heaters in combination of any of the forms of flow regulator above described.

Claims

1. A fluid flow regulator comprising a substantially straight tubular body whose ends are arranged to be connected to co-operating inlet and outlet pipes, and which incorporates a partition separating the interior of the housing into an inlet and an outlet compartment, the partition being provided with an opening which interconnects the compartments and being arranged so that the axis of the opening extends generally transverse to the body axis, a control member supported coaxially with respect to the opening, and an elastically deformable ring around the control member, the arrangement being such that the ring tends to deform due to the difference in pressures of the fluid in the inlet and outlet compartments and results in a change in crosssection of the flow path or paths through the opening in the sense which tends to maintain the rate of flow of fluid through the regulator approximately at a set value, and means for manually adjusting the position of the control member along the axis of the opening whereby the set rate of flow can be varied.

2. A fluid flow regulator according to Claim 1 wherein the ends of the tubular body are provided with standard means for coupling to inlet and outlet pipes.

3. A fluid flow regulator according to Claim 1 or 2 wherein the control member is carried by a threaded spindle screwed into a threaded sleeve supported by the body coaxial with the said opening, so that rotation of the spindle with respect to the sleeve produces an axial movement of the control member relative to the opening.

4. A fluid flow regulator according to Claim 3 wherein the spindle terminates outside the housing in a suitable manually adjustable control knob.

5. A fluid flow regulator according to any preceding claim wherein at least the part of the surface of the control member which co-operates with the ring is approximately of truncated conical shape narrower at the upstream end and axially movable within said opening, the elastically deformable ring being supported by the conical surface of the control member, such that as the pressure of fluid in the inlet compartment increases the ring is forced towards the larger end of the control member, thereby restricting the flow path through the opening, and when the pressure of fluid in the inlet compartment decreases the ring moves towards the narrower end of the control member, thereby increasing the flow path through the opening, the shape of the opening being such that varying the axial position of the member relative to the opening varies the rate of flow for a given difference between the inlet and outlet pressures.

6. A fluid flow regulator according to Claim 5 wherein the opening is of truncated conical shape narrower at the downstream end.

7. A fluid flow regulator according to Claim 5 wherein the opening is formed with one or more grooves extending longitudinally with respect to the opening and having a cross-section which diminishes towards the downstream end.

8. A fluid flow regulator according to any one of Claims 1 to 4 wherein at least the part of the surface of the control member which co-operates with the ring is of approximately cylindrical shape provided with one or more grooves extending along it and providing a flow path cr paths for the fluid between the control member and the ring, the depth of the groove or grooves varying along the length of the member, the ring being supported against any substantial axial movement with respect to the opening, and the arrangement being such that in use of the regulator the pressure of fluid in the inlet chamber urges the ring into the groove or grooves by an amount which increases with increasing pressure, thereby reducing the cross-section of the fluid flow path or paths by an amount which tends to maintain the fluid flow at said set value.

9. A fluid flow regulator according to Claim 8 wherein the groove or grooves is or are generally parallel to the axis of the control member.

10. A fluid flow regulator according to Claim 9 wherein the control member has a plurality of grooves separated by intervening ribs, and outer surfaces of the ribs are rounded so that they merge smoothly into the grooves.

11. A fluid flow regulator substantially as shown in and as hereinbefore described with reference to Figures 1 to 4 or Figure 5 or Figure 6 of the accompanying drawings.

12. A fluid flow regulator according to any preceding claim connected to, so as to control the flow of water through, an instantaneous electric water heater.