WO1995006220A1

WO1995006220A1 - Sealing gasket and pipe joints incorporating the same

Info

Publication number: WO1995006220A1
Application number: PCT/GB1994/001782
Authority: WO
Inventors: Thomas William Wildgoose
Original assignee: Victaulic Plc
Priority date: 1993-08-26
Filing date: 1994-08-15
Publication date: 1995-03-02
Also published as: GB2281766A; GB2281766B; GB9317934D0

Abstract

The invention provides a joint between a pair of juxtaposed spigot and socket pipe members (2, 15) which includes an annular elastomeric gasket (4) located between the confronting walls (18, 19) of the spigot and socket to provide a seal therebetween, and being retained in an annular recess (3) in the confronting wall of the spigot or the socket, the recess having a base (22) and two side walls (20, 21); the gasket (4) having a substantially V-shaped cross section, the apex (5) of the V-shape protruding, before make up of the joint, radially from the annular recess (3), the limbs (6, 7) of the V-shape being of such thickness and length that the outer ends (23, 24) thereof engage the side walls (20, 21) of the annular recess (3) over substantially the full height of each of the walls whereby the gasket (4) is positively restrained in the recess, the inner surfaces (8, 9) of the limbs (6, 7) together with the base (22) of the recess (3) defining a generally triangular shaped cavity (12), and the apex (5) of the V-shape being of a rounded configuration.

Description

SEALING GASKET AND PIPE JOINTS INCORPORATING THE SAME

This invention relates to a sealing gasket for providing a seal between two pipe elements and pipe joints incorporating the same.

It is known to create a spigot and socket type joint between two pipe ends by providing one pipe with a bell end into which is inserted the straight end of another pipe. Alternatively, a coupling sleeve can be provided for receiving within the bore thereof the ends of two pipes. With such joints, it is conventional to provide a sealing element which may be a compression sealing element such as a sealing ring or gasket formed of elastomeric material which is compressed between the outer diameter of the spigot element and the inner diameter of the socket element. The invention relates to such spigot and socket joints between pipe elements intended for low-pressure pipeline use such as surface water drainage for example so that the gaskets are generally intended to prevent leakage through the joint under low pressure conditions; they are not intended to withstand high fluid pressures within a pipeline.

The present invention relates to an improved gasket for use in such applications as well as a joint incorporating such a gasket.

Accordingly, in a first aspect, the invention provides a joint between a pair of juxtaposed spigot and socket pipe members which includes an annular elastomeric gasket located between the confronting walls of the spigot and socket to provide a seal therebetween, and being retained in an annular recess in the confronting wall of the spigot or the socket, the recess having a base and two side walls; the gasket having a substantially V-shaped cross-section, the apex of the V-shape protruding, before make up of the joint, radially from the annular recess, the limbs of the V-shape being of such thickness and length that the outer ends thereof engage the side walls of the annular recess over substantially the full height of each of the walls whereby the gasket is positively restrained in the recess, the inner surfaces of the limbs together with the base of the recess defining a generally triangular shaped cavity, and the apex of the V-shape being of a rounded configuration.

In one embodiment the socket is provided with an annular recess in which the gasket is located, the apex of the V-shape being oriented radially inwardly.

In another embodiment the radially outer surface of the spigot has an annular recess in which is located the gasket, the apex of the V-shape being oriented radially outwardly.

Preferably the limbs of the V-shape have radiussed edges which conform to and lie against correspondingly radiussed surfaces of the recess.

Preferably the apex of the V-shape has a rounded or radiussed configuration.

The rounded or radiussed apex may extend into generally planar faces defining the outer surfaces of the limbs of the V-shape. Preferably approximately two-thirds of the length of each generally planar face protrudes beyond the recess with the apex thereof, prior to making up the joint.

In a preferred embodiment, the limbs of the V-shape are not in contact with the base of the recess over the greater part of the axial length of the base. Most preferably the limbs of the V-shape are not in contact with the base of the recess over substantially all of the axial length of the base.

In a further aspect of the present invention, there is provided an annular elastomeric gasket having a configuration and dimensions especially suitable for use in a joint as hereinbefore defined.

It is to be understood that the term pipe element as used herein refers not only to pipes per se but also to other pipe or pipe-like members such as coupling sleeves, elbows, T-pieces, and like structures.

The gasket is formed of a suitable elastomeric material, the precise material depending upon the particular circumstances of use. For example, for use in water drainage systems, the gasket can be made of an elastomeric material such as ethylene propylene diene monomer (EPDM). Where the gasket is likely to come into contact with, for example, hot air, a fluoroelastomer may conveniently be used.

The invention will now be illustrated by reference to the particular embodiments shown in the accompanying drawings, in which;

Figure 1 is a sectional elevation of a pipe bend fitted with a gasket in accordance with one embodiment of the invention;

Figure 2 is an enlarged sectional elevation illustrating the arrangement of a gasket in the wall of a pipe element; and

Figure 3 is a fragmentary sectional elevation illustrating a gasket according to the embodiment shown in Figure 2, compressed between two pipe elements.

Referring now to the drawings, Figure 1 shows a pipe bend 1 having a bell end 2 of enlarged internal diameter. Bell end 2 is provided with an annular recess 3 around the inner diameter thereof. The annular recess 3 can accommodate an elastomeric gasket 4 according to one embodiment of the present invention.

As can be seen more clearly in Figure 2, an elastomeric gasket 4 according to one embodiment of the present invention has a cross-section in the form of a generally flattened V. The gasket 4 is seated in annular recess 3 extending around the radially inner surface of the bell end 2 of a pipe element. Gasket 4 is seated in the recess 3 such that the apex 5 of the V-shape protrudes from the recess 3, in this embodiment in a radially inward direction. Limbs 6 and 7 of the V-shape are seated within the recess 3, their ends 23, 24 abutting firmly side walls 20, 21 of the recess, the limbs 6 and 7 having radiussed edges 11 and 10 respectively which conform to and lie against correspondingly radiussed surfaces of the recess 3 linking the side walls 20, 21 and base 22 of the recess, whereby overall the gasket is securely restrained in the recess. The two inner surfaces 8 and 9 of the limbs 7 and 6 of the V-shape together with the base 22 of the recess define a generally triangular shaped cavity 12.

Apex 5 of the V-shaped elastomeric gasket is oriented radially away from the recess 3. Apex 5 is significantly radiussed, the radius extending into faces 13 and 14. Approximately two thirds of the lengths of each face 13, 14 protrudes beyond the recess 3 with the apex thereof.

In use, the straight end or spigot portion 15 of a pipe is inserted into the bell end 2 of the pipe bend. As shown in Figure 2, there is a small clearance 17 between the radially outer wall 18 of the pipe and the radially inner wall 19 of the bell end. As the pipe spigot 15 is advanced into the bell end 2, the edge 16 engages and slides along the face 13 of the elastomeric gasket, towards the radiussed apex 5. As it does so, the elastomeric gasket is deformed radially outwardly. Thus the elastomeric gasket is stretched onto the outside diameter of the pipe spigot 15, the resilient nature of the gasket causing it to grip the outer surface 18 of the pipe spigot and also the surfaces of the recess 3 in which it is seated. Figure 3 illustrates the pipe and elastomeric gasket in a sealed compressed state. It will be noted that the presence of the cavity 12 assists deformation of the gasket, thereby enabling the pipe end to be inserted more easily, but without reducing the sealing ability of the gasket.

The gasket illustrated in the drawings is shown as having a configuration wherein the apex of the V-shape is oriented radially inwardly. However, it is equally possible for the apex of the V-shape to be oriented radially outwardly, and a gasket constructed in this manner could, for example, be seated in an annular recess on the radially outer surface of a spigot end of a pipe element.

The gasket and joint of the invention have been found to be particularly effective in providing satisfactory sealing for pipe elements of the kind to which the invention is particularly applicable as hereinabove described. It is believed that this is because the gasket and the joint in which it is included, in use, constitutes a structure which allows a high level of radial gasket movement and deflection, thereby generating high internal stress within the gasket and thus reaction.

It is believed that in operation the radiussed apex of the V-shape, defining the inner diameter of the gasket and the sealing edge, is stretched radially outwards upon insertion of the spigot of the inner pipe and thus firmly grips the inner pipe.

In addition the gasket, by its configuration, is most securely restrained within the recess within which it is seated, especially against the side walls thereof, which prevents any axial movement of the gasket, particularly at the radially outer surface of the inner pipe.

The restraining effect just mentioned, is enhanced by the radial tension forces along the apex of the gasket as this is stretched on insertion of the spigot, by the surface tensions on the radially inner inclined surfaces of the V-shape, and by the axial compressions across the radially outer inclined surfaces of the V.

The stress created by the effects just mentioned provides forces acting opposite to those produced by insertion of the spigot which cause the initial closure compression, and provides long term sealing.

It will readily be appreciated that numerous modifications and alterations may be made to the specific embodiments shown in the drawings, and all such modifications and alterations are intended to be embraced by this application. CLAIMS

1. A joint between a pair of juxtaposed spigot and socket pipe members which includes an annular elastomeric gasket located between the confronting walls of the spigot and socket to provide a seal therebetween, and being retained in an annular recess in the confronting wall of the spigot or the socket, the recess having a base and two side walls; the gasket having a substantially V-shaped cross-section, the apex of the V-shape protruding, before make up of the joint, radially from the annular recess, the limbs of the V- shape being of such thickness and length that the outer ends thereof engage the side walls of the annular recess over substantially the full height of each of the walls whereby the gasket is positively restrained in the recess, the inner surfaces of the limbs together with the base of the recess defining a generally triangular shaped cavity, and the apex of the V-shape being of a rounded configuration.

2. A joint according to Claim 1 wherein the socket is provided with an annular recess in which the gasket is located, the apex of the V-shape of the gasket being oriented radially inwardly.

3. A joint according to Claim 2 wherein the radially

Claims

outer surface of the spigot has an annular recess in which is located the gasket, the apex of the V-shape being oriented radially outwardly.

4. A joint according to Claim 1 or Claim 2 wherein the libs of the V-shape have radiussed edges which conform to and lie against correspondingly radiussed surfaces of the recess.

5. A joint according to any one of the preceding Claims wherein the apex of the V-shape has a rounded or radiussed configuration.

6. A joint according to Claim 5 wherein the rounded or radiussed apex extends into generally planar faces defining the outer surfaces of the limbs of the V- shape.

7. A joint according to Claim 6 wherein approximately two thirds of the length of each generally planar face protrudes beyond the recess with the apex thereof.

8. A joint according to any one of the preceding Claims wherein the libs of the V-shape are not in contact with the base of the recess over the greater part of the axial length of the base.

9. A joint according to Claim 8 wherein the limbs of the V-shape are not in contact with the base of the recess over substantially all of the axial length of the base.

10. An annular elastomeric gasket having a configuration suitable for use in a joint according to any one of the preceding Claims.