GB2042128A - Fluid flow control valve - Google Patents

Abstract

The valve comprises a resiliently deformable tube 12 adapted to be connected into and form part of a pipeline for the fluid. An anvil 25 is adapted to make line contact with the outside of the tube and a stirrup member 15 in the form of a closed loop surrounding the tube is also adapted to make line contact with the outside of the tube at a position diametrically opposite to and co-planar with the line of contact of the anvil. A spring 19 biasses the stirrup member in a direction to cause the tube to be pinched between the stirrup and the anvil to close off the tube. Actuating means, for example a pneumatic actuater 28, is provided for displacing the stirrup against the spring bias to allow the tube to open. <IMAGE>

Description

SPECIFICATION Fluid-flow control valves This invention relates to fluid-flow control valves.

More particularly, but not exclusively, the invention is concerned with valves suitable for controlling the flow of clay slip along a feed pipeline to a casting station for ceramic articles.

The object of the invention is to provide a valve which is reliable in the arduous conditions under which it has to operate when controlling the flow of clay slip, and which at the same time can be made of small size and at a relatively low cost.

According to the present invention, a fluid-flow control valve comprises a resiliently deformable tube adapted to be connected into and form part of a pipeline for the fluid, an anvil member adapted to make substantially line contact with the outside of the tube, a stirrup member in the form of a closed loop surrounding the tube and adapted to make substantially line contact with the outside of the tube at a position diametrically opposite and substantially co-planar with the line contact of said anvil, spring means biassing said stirrup member in a direction to cause said tube to be pinched between said stirrup and said anvil to close off said tube and actuating means for displacing said stirrup against said spring bias whereby to allow said tube to open.

One construction of valve in accordance with the invention and suitable for controlling the flow of clay slip to a casting station for ceramic articles will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a longitudinal central section through the valve and shows the valve in its open position, and Figure 2 is a similar view of the valve but shows the valve in its closed position.

The valve has a rectangular plastics casing 1 formed from two half casings 2 and 3 which are secured together through metal yokes 4 and 5. The yokes 4 and 5 locate at each end of and within the casing 1 and have lugs 6 with screw-holes 7 which align with screw holes 8 in the half casings 2 and 3.

Self-tapping screws (now shown) pass through the screw holes 8 and are screwed into the screw-holes 7 to clamp the half casings 2 and 3 to the yokes 4 and 5 and, as will become apparent, to clamp various items of the valve in position within the casing 1. The yokes 4 and 5 are each provided with a central hole in which is located a plastics stub pipe, referenced 9 in the case of yoke 4 and 10 in the case of yoke 5. The end walls of each of the two half casings 2 and 3 are provided with semi-circular cut-outs so that they locate around the stub pipes 9 and 10. The stub pipes 9 and 10 serve to connect the valve into a slip pipe-line. Thus one stub pipe acts as an inlet to the valve and the other as an outlet from the valve.

The facing inner ends of the stub pipes 9 and 10 are interconnected by a resiliently flexible tube 12.

Advantageously the tube 12 is formed of a high temperature silicon rubber. Trials have shown that such a tube will withstand internal abrasion, does not become permanently deformed by the action of the valve or the flow of clay slip through the valve and does not clog or become congested with clay slip. The ends of the tube 12 are clamped to the stub pipes 9 and 10 by hose clips 13.

A plastics stirrup member 14 in the form of a closed rectangular loop surrounds the tube 12 and is fitted over one end of the tube 12 before the tube 12 is fitted to the stub pipes. Along one side of the stirrup 14, the lower side as seen in the drawings, the periphery of the rectangular aperture in the stirrup 14 is defined by what will be termed a blade 15 having a rounded free edge for making substantially line contact with the tube 12. Along the upper side of the stirrup 14, the periphery of the rectangular aperture in the stirrup 14 is defined by a rounded protuberance 16. The periphery of the aperture along its other two sides, i.e. the vertical sides, is formed by planar surfaces. Extending downwardly from the mid-length of the lower side of the stirrup 14 is a pin-like projection (not visible) on to which is push fitted a plastics post 17.Extending upwardly from the mid-length of upper side of the stirrup 14 is a small pip 18 which, as will be described, locates in a part of a pneumatic actuating device.

A compression spring 19 locates around the post 17 and abuts at one end against the lower side of the stirrup 14. At its other end the spring 14 abuts against the bottom of cup 20. The cup 20 is formed separately from the casing and is a push fit in a hole in the half casing 2, being fitted from the inside of the half casing 2 so that its flange 22 rests against the inner surface of the half casing 2. Thus the stirrup 14 is biassed upwardly as seen in the drawings by the spring 19 to urge the blade 15 against the tube 12.

The stirrup 14 is guided for vertical movement by guides in the side-walls of the casing parts 2 and 3 and comprising inwardly projecting pairs of ribs 21 between which the vertical sides of the stirrup 14 locate.

A substantially 'V' - sectioned member, which will be termed an anvil, 23 locates at the free ends of its two limbs in the half casing 3 and forthis purpose is provided with small cylindrical pips 24 which locate in complementary cylindrical recesses in the inner surface of the half casing 3. The anvil 23 passes through the aperture in the stirrup 14 and the width of its limbs is just slightly less than the length of the blade 15 so that the anvil can be fitted through the stirrup 14. The apex of the 'V' therefore provides a knife-edge 25, so to speak, which faces and is co-planar with the blade 15. Thus, under the spring bias the tube 12 is pinched between the knife edge 25 of the anvil 23 and the blade 15 and is closed off so that slip can not flow through the tube 12. This constitutes the normally closed position of the valve.

Secured to the outside of the casing part 3 is a pneumatic actuating device 26 for moving the valve to its open position against the bias of spring 19. The device 26 comprises a plate 27 to which a domeshaped diaphragm 28 is secured by adhesive. The plate 27 is secured to the casing part 3 by four screws two of which also serve to clamp the solenoid operated control valve 29 in position on top of the plate 27. The diaphragm 28 extends into the casing 1 through a hole in the half casing 3 which is similar in size to the hole in the half casing 2 for receiving the spring locating cup 20. The diaphragm has a plastics disc 30 secured to its head by adhesive. The disc 30 abuts the upper side of the stirrup and has a small cylindrical recess at its centre for locating the pip 18.

A small diameter copper pipe 32 is bonded into a connector portion 33 of the plate 27 and serves as the inlet for air from a pressurised source to the pneumatic actuating device. A duct 34 within the plate 27 leads from the connector portion to an orifice in the top of the plate 27. A further duct 35 extends through the plate 27 so that its orifice on the underside of the plate 27 leads to the interior of the diaphragm 28. The orifices of the two ducts 34 and 35 are interconnected through the solenoid operated control valve 29 which is sealed to the top of the plate 27 through a cork gasket 36.

When the control valve 29 is unenergised the duct 35 is open to atmosphere through the valve 29 so that the tube 12 is closed off underthe bias of the spring 19. When energised the valve 29 connects the ducts 34 and 35 so that the diaphragm is distended to displace the stirrup 14 against the spring bias and cause the blade 15 to move away from the anvil 23.

Hence the tube 12 opens up under its own resilience and the pressure of slip in the pipeline.

In the design of the above described valve, the length of the tube 12 is controlled to tolerances that will allow the tube to become deformed sufficiently to close it off. The spring 19 is chosen to have a rate necessary to provide the correct squeezing pressures on the tube 12 whilst allowing the diaphragm to compress it to open the tube 12.

Although in the above described valve a pneumatic actuating device 26 has been used whereby an electrical signal is converted to a mechanical movement, the actuating device 26 in certain operating circumstances could be dispensed with and replaced by a simple mechanical lever acting directly on the stirrup 14.

As can be seen from the drawings, the two half casings 2 and 3 can be formed as identical mouldings and then by small modifications can be adapted for use either as the half casing 2 orthe half casing 3.

Advantageously the diaphragm 28 is fixed to the plate 27 by the use of contact adhesive to form a sub-unit with the plate 27. If the diaphragm has to be replaced the sub-unit can be placed into near boiling water to destroy the adhesive bond after which a new diaphragm can be fitted.

Claims (13)

1. A fluid-flow control valve comprising a resiliently deformable tube adapted to be connected into and form part of a pipeline for the fluid, an anvil member adapted to make substantially line contact with the outside of the tube, a stirrup member in the form of a closed loop surrounding the tube and adapted to make substantially line contact with the outside of the tube at a position diametrically opposite to and substantially co-planar with the line contact of said anvil member, spring means biassing said stirrup member in a direction to cause said tube to be pinched between said stirrup and said anvil member to close off said tube and actuating means for displacing said stirrup against said spring bias whereby to allow said tube to open.

2. A fluid-flow control valve according to claim 1, wherein said actuating means is pneumatic and comprises a diaphragm which engages said stirrup and which when pressurised is distended to a dome-shape to move said stirrup against the spring bias.

3. A fluid-flow control valve according to claim 2, wherein a plate member through which said diaphragm engages said stirrup is secured by adhesive to said diaphragm.

4. A fluid-flow control valve according to claim 3, wherein said stirrup member is provided with a pip-like projection which locates in a recess in said plate member.

5. A fluid-flow control valve according to any preceding claim, wherein said stirrup member is in the form of a rectangular closed loop, a blade being provided along one side of the loop on the inner periphery thereof for making the substantially line contact with the tube, the opposite side of said loop being arranged to be engaged by said actuating means and the two remaining sides of said loop being located in guides for guiding the movement of said stirrup member.

6. A fluid-flow control valve according to claim 5, wherein said spring means comprises a compression spring engaging at one end against the outer periphery of said one side of said closed loop and locating over a post which extends from and is connected with said one side of said closed loop.

7. A fluid-flow control valve according to any preceding claim, wherein said anvil member is substantially of 'V' form arranged so that its apex makes the substantially line contact with the tube and with the free ends of its limbs located in recesses in a casing of the valve.

8. A fluid-flow control valve according to any preceding claim and having a casing formed by two half-casings which are secured together.

9. A fluid-flow control valve according to claim 8 wherein said half casings are formed as identical mouldings.

10. A fluid-flow control valve according to claim 9 wherein said half casings are provided with semi-circularcut-outswhich when the half casings are fitted together locate around stub pipes which serve as an inlet and an outlet respectively of the valve and between which said deformable tube extends within the casing.

11. A fluid-flow control valve according to claim 9 or 10, wherein said half casings are formed with holes which face each otherwhen the half casings are fitted together, one of said holes locating said actuating means in the form of a diagphragm, and the other hole locating a cup-member in which the spring means in the form of a compression spring locates with one end of the compression spring engaging the bottom of the cup member, the other end of the compression spring engaging said stirrup member.

12. A fluid-flow control valve according to any preceding claim, wherein said actuating means is pneumatic actuating means having a solenoid operated control valve for controlling the pressurisation of said pneumatic actuating means.

13. Afluid-flow control valve substantially as hereinbefore described with reference to the accom panying drawings.