GB2244791A - Valve - Google Patents

Abstract

A valve suitable for use in the inflation of a bag stopper within a drain pipe for pressure testing or sealing comprises a housing (12) with an inlet (18) and an outlet (26) which is adapted to receive a flexible tube. The housing (12) encloses a chamber in which a valve member (14) is manually movable in a direction transverse to a flow passage through the valve from a closed position towards which it is spring-biased (15), and a range of open positions. A part-annular subchamber (48) is provided in the chamber by a skirt portion (46), an annular edge (50) of which sealingly engages the valve member in the closed condition of the valve. The valve member (14) is provided with gaps around its margins to allow a back pressure of fluid from the part-annular subchamber (48) into further subchamber (60) axially arranged with respect to the valve member (14) to assist in keeping the valve fully closed. <IMAGE>

Description

VALVE The invention is concerned with improvements in or relating to valves.

The invention relates to a valve which may be particularly, but not exclusively, suitable for use in association with an inflatable bag stopper.

In pipe installations which are utilised for example as drains or as gas conduits it is often desirable to seal a section of pipework from the adjacent pipe whether for pressure testing or for any other reason. The sealing of such a section from the rest of the pipe is often performed by inflating a rubber bag within the pipe. Such inflatable bags may be inserted at appropriate locations and controllably inflated through a taper plug cock associated with each bag. These cocks are often difficult to access and operate, and are liable to leakage.

It is desirable that a valve be provided for this purpose which can cope with high fluid pressure and which is relatively inexpensive. The valve should also be relatively easy to manufacture and assemble. The valve should be easy to operate and be leak-free at pressures up to 30 psi.

It is an object of the present invention to provide a valve which assists in achieving the foregoing desirable features.

The invention provides a valve comprising a housing defining a flow passage for fluid therethrough, said housing comprising a main body portion, an inlet to a chamber of the body portion and an outlet therefrom, a valve member being arranged for movement within the body portion in a direction at least substantially transverse to said flow passage, said movement taking place between a closed position into which it is spring-biased, and open positions in which fluid flow occurs in said passage, wherein said body member is provided with a skirt portion extending into the chamber of said member to define a part-annular peripherally disposed subchamber upstream of the outlet, a free end surface of said skirt portion providing at least a portion of a valve seat for contact with the valve member in the closed position.

Advantageously, the valve member is provided with an enlarged flange portion adapted to be received in a region of the body portion chamber so as to provide a further subchamber, and means to provide communication between the further subchamber and the peripherally disposed part-annular subchamber so that when the valve is closed, the effect of back-pressure from the outlet passes to the further subchamber and impinges upon the flange portion to reinforce the closure of the valve member and assist in maintaining the latter against the valve seat.

Conveniently, the enlarged flange portion may be provided with apertures therein to provide said communication, or as in the example to be described below a discontinuous annular passageway is provided around the enlarged flange portion, said passageway being partly defined by a plurality of protruding spacer means provided between the flange portion and a wall of the body portion chamber.

An embodiment of the present invention will now be described, by way of example only, with reference to the drawings, in which: Figure 1 is a longitudinal cross-section through an example of a valve according to the invention, showing the valve in an open condition; Figure 2 is a similar cross-sectional view to that of Figure 1, showing the valve in a closed condition; Figure 3 is a plan view of the valve; Figure 4 is a side view of a valve member; and Figure 5 is a sectional view of an end cap of the valve.

Reference is firstly made to Figures 1 and 2 of the drawings which show a valve generally indicated by reference numeral 10. The valve 10 is injection moulded from a synthetic plastics material, in the present example an acetal plastics material, and may conveniently be used as a means of controlling air flow to an inflatable bag (not shown) of the type which is commonly used to seal a section of pipework by inflating the bag inside a pipe thus preventing fluid flow along the pipe past the inflated bag. With an inflated bag of this type in position in the pipe, a section of pipework downstream of the inflated bag may be removed, replaced or pressure tested without fluid leaking from the pipe.

The valve 10 consists of a housing 12 and a valve member 14 movable within the housing 12 to open and close the valve 10 as will be described later in detail. The housing 12 consists of a male or female screw-threaded connection portion 16 which defines an inlet and exhaust flow channel 18, a generally cylindrical body portion 20 which defines a chambers 22 and 23 in which the valve member 14 is movably positioned, and an outlet tube connection portion 24 which defines an outlet flow channel 26. The outlet tube connection portion 24 has a bulbous outer surface 28 which allows a flexible tube or inflatable bag (not shown) to be removably connected thereto.When the valve 10 is open, an inflatable bag, connected to outlet tube connection portion 24, will be inflated by air flowing from an external air source, through inlet and exhaust flow channel 18, chambers 22 and 23 and outlet flow channel 26.

The valve member 14 is movable transversely of the body portion 20 between a first position as shown in Figure 1, where the valve 10 is open and fluid flows through the valve 10, and a second, closed, position as shown in Figure 2. The valve member 14 may be moved to the open, depressed, position by pushing the valve member 14 downwards with the thumb and is returned to the closed position by a coil compression spring 15 positioned within the valve member 14.

The valve member 14 consists of a first cylindrical portion 30 in which an annular recess 32 is formed for receiving an '0' ring seal 34, a second cylindrical portion 36 having a smaller diameter than the first cylindrical portion 30,a third cylindrical portion 38 having the same diameter as the first cylindrical portion 30; a second annular recess 40 for receiving a second '0' ring seal 42, and a cylindrical end flange 44.

The outer surfaces of the first cylindrical portion 30 and the cylindrical end flange 44 slidably engage the inner surfaces respectively of cylindrical chambers 22 and 23 in the cylindrical body portion 20 of housing 12.

A cylindrical skirt 46 in the body portion 20 whose inner surface defines chamber 22 extends into chamber 23 and separates chamber 22 from an outer, part-annular subchamber 48 which communicates with outlet flow channel 26 but does not extend fully around the periphery of the chamber 22 so that it is not in communication with inlet and exhaust channel 18 (See Figure 3) when the valve is closed.

Fluid flows from the chamber 22 through the subchamber 48 to the outlet flow channel 26 when the valve 10 is open. The skirt 46 has a bevelled end surface 50 which provides a valve seat for the '0' ring seal 42. When the valve member 14 is in the closed position, the valve member is biased upwardly by the force of the compression spring 15 and the '0' ring seal 42 is compressed into sealing engagement between the cylindrical end flange 44 of the valve member 14 and the surface 50.

This prevents a fluid flow from subchamber 48 through chamber 23 to chamber 22. When the valve member 14 is depressed, the third cylindrical portion 38 of the valve member 14 is moved downwardly carrying '0' ring seal 42 out of sealing engagement with the surface 50. Thus when the valve member 14 is depressed, fluid flows from inlet and exhaust channel 18, through chambers 22 and 23 and into subchamber 48 and then to outlet channel 26 and vice versa. The further valve member 14 is depressed, the larger the gap between the surface 50 and '0' ring seal 42, to allow greater volumes of fluid to flow from chamber 22 into subchamber 48 and vice versa.

The spring 15 is received within the hollow interior 55 (Figures 4) of the valve member 14, an end portion of the spring being received in a recess 58 provided by a cylindrical wall 56 formed in an end cap 54 (Figure 5), permanently secured to the lower portion of the body portion 12.

When the valve member 14 is in the closed position and '0' ring seal 42 is held against the surface 50, the end flange 44 of the valve member 14, the wall of body portion 20 and the valve cap 54 define a further subchamber 60 below the valve member 14. The end flange 44 of the valve member 14 has eight equi-spaced protruding spacers 49 provided on its periphery so that there may be a back pressure of fluid from the chamber 48 into the chamber 60. The fluid pressure in the third chamber 60 assists the action of spring 15 to maintain valve 14 in the closed position. When as in the present example the valve is used to inflate an inflatable bag, the back pressure provided by the air in the inflated bag assists in keeping the valve 10 firmly closed.

Various modifications may be made with the scope of the present invention as defined by the following claims.

The valve may be made of any suitable material, not necessarily a plastics material, although this is preferred. The inlet and outlet channels may be offset from one another although alignment of the channels is preferred. If preferred, the skirt portion may be disposed adjacent the fluid inlet thus defining a fluid inlet chamber between the inlet and the control chamber, the outlet channel then being sealed when the valve is closed.

Advantages associated with the present invention include a valve which gives improved performance with high pressure fluid flow,and simple actuation using the thumb.

The valve is relatively inexpensive to manufacture utilizing plastics moulding techniques and is more easily assembled than existing taper plug brass cocks.

Claims (9)

1. A valve comprising a housing defining a flow passage for fluid therethrough, said housing comprising a main body portion, an inlet to a chamber of the body portion and an outlet therefrom, a valve member being arranged for movement within the body portion in a direction at least substantially transverse to said flow passage, said movement taking place between a closed position into which it is spring-biased, and open positions in which fluid flow occurs in said passage, wherein said body member is provided with a skirt portion extending into the chamber of said member to define a part-annular peripherally disposed subchamber upstream of the outlet, a free end surface of said skirt portion providing at least a portion of a valve seat for contact with the valve member in the closed position.

2. A valve as claimed in claim 1, wherein the valve member is provided with an enlarged flange portion adapted to be received in a region of the body portion chamber so as to provide a further subchamber, and means to provide communication between the further subchamber and the peripherally disposed part-annular subchamber so that when the valve is closed, the effect of back-pressure from the outlet passes to the further subchamber and impinges upon the flange portion to reinforce the closure of the valve member and assist in maintaining the latter against the valve seat.

3. A valve as claimed in claim 2, wherein said communication is provided by a discontinuous annular passageway around the enlarged flange portion and partly defined by a plurality of spacer means provided between the flange portion and a wall of the body portion chamber.

4. A valve as claimed in claim 2, wherein said communication is provided by apertures formed in said enlarged flange portion.

5. A valve as claimed in any one of the preceding claims, wherein the outlet is adapted in use to receive a flexible tube or inflatable bag in an air-tight manner.

6. A valve as claimed in any one of the preceding claims wherein the valve member is movable manually from said closed position to a selected open position in a range of said open positions.

7. A valve as claimed in any one of the preceding claims wherein the valve member is provided with a sealing member which is adapted in the closed position sealingly to engage an annular valve seat surface of said skirt portion.

8. A valve as claimed in claim 7, wherein said skirt portion acts as a baffle to divert the path of said flow passage between said inlet and said outlet, the subchamber formed thereby being in communication with the inlet or outlet at all times.

9. A valve constructed and arranged substantially as hereinbefore described with reference to and as shown in the drawings.