GB2237860A - Flow control device - Google Patents

Abstract

A flow control device 2 for a fluid flow-line comprises a cylindrical inner core 19 having a plurality of circumferentially spaced longitudinal grooves 33 co-operable with an outer sealing ring 17 to define a plurality of orifices for fluid flow. At least some of the grooves 33 are terminated by a helical land portion 34 that is co-operable with the outer sealing ring 17 on relative axial movement of the ring 17 and core 19 to vary the number of orifices available for fluid flow whereby the flow rate is controlled. <IMAGE>

Description

DEVICE This invention relates to a device for controlling the flow rate of fluids, such as water.

Devices for controlling the flow rate of fluids have a wide range of applications to equipment and apparatus for both domestic and industrial use. By way of example, such devices may be used to control the flow rate of the water supply in ablutionary appliances for bathing or showering, in washing machines, dishwashers and like appliances, and in water heaters.

The devices may also be used to control the flow rate of fluids in industrial processes.

It is an object of the present invention to provide a device for controlling the flow rate of fluids that is simple in construction, efficient in operation, and effective in a wide range of applications.

Another object of the present invention is to provide a device for controlling the flow rate of fluids that is easy to manufacture, is accurate and reliable, and is relatively inexpensive.

According to the present invention we provide a device for controlling the flow rate of a fluid comprising a cylindrical inner member having a plurality of longitudinal grooves co-operable with an annular outer member to define a plurality of orifices for fluid flow and a land portion co-operable with the outer member on relative axial movement of the members to adjust the number of orifices available for fluid flow whereby the flow rate is''sontrolled.

By this invention, the inner and outer members are co-operable to define orifices for fluid flow and relative axial movement of the members changes the number of orifices available for fluid flow to control the flow rate.

Preferably, each groove is of uniform crosssection throughout its axial length. By maintaining a constant cross-section for each groove, manufacture of the inner member is facilitated.

Advantageously, the inner member is arranged for limited axial movement relative to the outer member between first and second end positions corresponding to minimum and maximum flow rates respectively. For example, the inner member may be coupled to an actuator for such limited axial movement with the outer member being held stationary.

The land portion may be co-operable with the outer member to close all the orifices to prevent fluid flow through the device in the first end position.

Alternatively, at least one groove may be cooperable with the outer member to permit fluid flow through the device in the first end position.

The invention will now be described in more detail by way of example only with reference to the accompanying drawings, wherein: FIGURE 1 is a cross-section of a valve incorporating the invented flow control device and showing the device adjusted for minimum flow rate; FIGURE 2 is a cross-section of the valve similar to Figure 1 and showing the device adjusted for maximum flow rate; FIGURE 3 is a cross-section of the valve similar to Figures 1 and 2 and showing the device adjusted for a flow rate intermediate the minimum and maximum flow rates; FIGURE 4 is a section on the line 4-4 of Figure 1; FIGURE 5 is an isometric view of the inner member of the device shown in Figures 1 to 3; FIGURE 6 is a side view of the inner member shown in Figure 5; FIGURE 7 is an end view of the inner member shown in Figures 5 and 6;; FIGURE 8 is a developed view of the inner member shown in Figures 5 to 7; and FIGURE 9 is an end view of the inner and outer members of the device at low pressure with the housing shown partly in section.

Referring first to Figures 1 to 4 of the accompanying drawings, a valve 1 for controlling fluid flow in a flow-line is shown incorporating a flow control device 2 according to the present invention for controlling the fluid flow rate.

The valve 1 comprises a body 3 having an inlet passage 4 and an outlet passage 5 separated at the inner ends by an internal dividing wall 6 and externally threaded at the outer ends for connection to respective pipes (not shown) of the flow-line. The body 3 may be of metal, alloy or plastics and is preferably formed in one piece. The outer ends of the passages 4,5 may be adapted for connection in the flowline by any suitable means.

A bonnet 7 carrying a rotatable control shaft 8 is releasably secured to the body 3 by four screws 9 and is sealed by a sealing ring 10 located and retained in an annular recess 11 defined between the body 3 and bonnet 7.

The shaft 8 extends through and is sealed relative to an opening 12 in the bonnet 7 by a sealing ring 13 and is axially retained by a circlip 14.

The outer end of the shaft 8 is provided with splines 15 for engagement by complementary splines of a control knob (not shown) for manually rotating the control shaft 8.

The.inner end of the shaft 8 threadably engages a piston 16 received in the bonnet 7. The opposed surfaces of the piston 16 and bonnet 7 are of hexagonal or other suitable non-circular cross-section such that the piston 16 is retained against rotation but is axially slidable relative to the bonnet 7 by rotation of the control shaft 8 in opposed senses.

The flow control device 2 comprises a flexible sealing ring 17 of natural or synthetic rubber or plastics mounted in an opening 18 in the dividing wall 6 and a cylindrical core 19 of plastics or metal secured to the piston 16 by a screw 20 for axial movement relative to the O-ring 17 to control the flow rate.

A housing 21 for the sealing ring 17 comprises a tubular seating member 22 having a radial lip 23 providing a seating face 24 for the sealing ring 17 and a stepped bore 25 providing an internal abutment face 26 for a retainer ring 27 to axially locate the sealing ring 17 and an external abutment face 28 to axially locate the seating member 22 in the opening 18.

The assembly of the seating member 22, sealing ring 17 and retainer ring 27 is releasably retained in the opening 18 by a detachable locking ring 29 secured to the dividing wall 6 by screws 30.

The core 19 is axially movable relative to the sealing ring 17 between first and second end positions shown in Figures 1 and 2 respectively corresponding to minimum and maximum flow rates. Travel of the core 19 is limited by engagement of the opposed ends of the piston 16 with the end wall of the bonnet 7 and with one or more lugs 31 on the locking ring 29.

Referring now to Figures 5 to 9, the cylindrical core 19 is formed with sixteen circumferentially spaced longitudinal ribs 32 defining sixteen longitudinal grooves 33 extending from one end and a part-circumferential helical land portion 34 extending from the other end. Alternate ribs 32 are of reduced height in the radial direction but this is not essential and the ribs may all be of the same height.

Each groove 33 is of uniform cross-section throughout its axial length and is co-operable with the sealing ring 17 to define an orifice 35 for fluid flow.

The land portion 34 is co-operable with the sealing ring 17 on axial movement of the core 19 to adjust the number of orifices 35 available for fluid flow thereby controlling the flow rate.

In this embodiment, four grooves 33' have an axial length to co-operate with the sealing ring 17 at all axial positions of adjustment of the core 19. The remaining twelve grooves 33" are terminated by the land portion 34 and are of progressively reduced axial length to co-operate progressively with the sealing ring 17 on axial displacement of the core 19.

In this way, the helical land portion 34 is cooperable with the sealing ring 17 on axial movement of the core 19 to adjust progressively the number of orifices 35 available for fluid flow from four in the first end position corresponding to the minimum flow rate up to sixteen in the second end position corresponding to the maximum flow rate.

As a result, by adjusting the axial position of the core 19, the flow rate can be selected as desired.

By way of example, an intermediate position of adjustment of the core 19 corresponding to a flow rate between the minimum and maximum flow rates is shown in Figure 3.

For any given setting of the core 19, fluctuations in the fluid pressure are automatically compensated by radial deformation of the sealing ring 17 to vary the size of the orifices 35 to maintain the selected flow rate substantially constant.

It will be understood that the invented flow control device is not limited to the embodiment and application above-described. For example, the inner member may have more than or less than sixteen grooves for co-operating with the outer member.

The grooves may have any desired cross-section but are preferably of constant cross-section throughout their effective length so that the size of the orifice formed by co-operation with the outer member is independent of the axial position of the inner member.

By maintaining a constant cross-section along the effective length of each groove, manufacture of the inner member is considerably simplified.

The land portion may be co-operable with the outer member so that more than or less than four orifices remain open in the position of minimum flow.

Alternatively, the land portion may co-operate with the outer member to close all the orifices in the position of minimum flow preventing any flow through the device.

The land portion may have a shape other than helical to provide a range of grooves of different effective length, for example the land portion may be of stepped profile.

Each groove may be terminated at the land portion to provide any desired flow characteristics for a given application of the device. For example, each groove may be tapered off over a short distance or stopped off square to the longitudinal axis of the groove.

The outer member may comprise an elastic ring of circular or non-circular cross-section, for example oval or square.

The inner member may be held stationary and the outer member mounted for axial movement relative thereto.

Claims (12)

Claims:

1. A device for controlling the flow rate of a fluid comprising a cylindrical inner member having a plurality of longitudinal grooves co-operable with an annular outer member to define a plurality of orifices for fluid flow and a land portion co-operable with the outer member on relative axial movement of the members to adjust the number of orifices available for fluid flow whereby the flow rate is controlled.

2. A device according to Claim 1 wherein each groove is of uniform cross-section throughout its axial length.

3. 'A device according to Claim 1 or Claim 2 wherein the inner member is arranged for limited axial movement relative to the outer member between first and second end positions corresponding to minimum and maximum flow rates respectively.

4. A device according to Claim 3 wherein the outer member is co-operable with the land portion to close all the grooves in the first end position.

5. A device according to Claim 3 wherein the outer member is co-operable with at least one groove in the first end position.

6. A device according to any one of the preceding Claims wherein the land portion is of helical profile.

7. A device according to any one of Claims 1 to 5 wherein the land portion is of stepped profile.

8. A device according to any one of the preceding Claims wherein the inner member is provided with a plurality of circumferentially spaced longitudinal ribs defining the grooves.

9. A device according to Claim 8 wherein alternate ribs in the circumferntial direction are of reduced height.

10. A device according to any one of the preceding Claims wherein the outer member comprises an elastic ring.

11. A device for controlling the flow rate of a fluid substantially as hereinbefore described with reference to the accompanying drawings.

12. A valve incorporating a device according to any one of the preceding Claims.