GB2274888A

GB2274888A - Seal for spigot and socket pipe joints

Info

Publication number: GB2274888A
Application number: GB9302477A
Authority: GB
Inventors: Andrew Reginald Lee
Original assignee: HARMER HOLDINGS Ltd
Current assignee: HARMER HOLDINGS Ltd
Priority date: 1993-02-09
Filing date: 1993-02-09
Publication date: 1994-08-10
Anticipated expiration: 2013-02-09
Also published as: GB9302477D0; GB2274888B

Abstract

The seal 10 is used in a joint between telescoped lengths of pipe, e.g. between the spigot 16 of a drain fitting and a surrounding soil pipe. The seal 10 includes a radially inwardly extending abutment 30 for properly locating the seal between the lengths of pipe. The seal 10 preferably includes inner circumferential beads 14 and outer deflectable circumferential fins 23 of various heights to seal against outer pipes of various diameters. The seal 10 may include a manually graspable sleeve 28 engageable with a shoulder on the inner pipe length. <IMAGE>

Description

PIPE SEAL This invention relates to a seal for making fluid-tight joints between telescoped lengths of pipe, for example between the spigot of a drain fitting and a surrounding soil pipe as disclosed in our co-pending application entitled "Drains", although the pipe seal of the present invention is not limited to such use.

A seal is known, for installation between an inner pipe length and an outer pipe length, the seal comprising a generally tubular body of rubber or like resilient material.

The bore of the body is formed with a number of circumferential beads; the body being stretched by insertion of the inner pipe to make a tight sliding fit therewith.

The outer surface of the body carries a number of circumferential fins for co-operation with the bore of the outer pipe length. The radial height of the fins is chosen such that they are slightly deflected when the seal is installed between the pipe lengths, thereby to seal against the bore of the outer pipe length. Small variations in the outside diameter of the inner pipe and slightly greater variations in the outer pipe bore size can thus be accommodated, by the degree of stretching of the seal body and the degree of deflection of the fins respectively.

To ensure that it is properly seated between the pipe ends in use, the known seal is provided with a radially outwardly extending rim. The seal is first installed within the outer pipe length with the rim seated against the end of the outer pipe length. The inner pipe length is then inserted through the seal into the outer pipe length.

The known seal is satisfactory provided that the outer pipe end forms a well-defined shoulder for co-operation with the pipe seal rim, ensuring that the pipe seal remains properly seated within the outer pipe length. However in many cases (for example where the inner pipe length is the spigot of a refurbishment roof outlet and the outer pipe length is an existing soil pipe, as disclosed in our copending application) the outer pipe will be provided with a flared end, whose dimensions will vary from case to case.

The seal rim therefore cannot reliably locate the seal in all applications.

In accordance with the present invention, there is provided a fluid seal comprising a generally tubular body having a radially inner surface for sealing co-operation with an inner pipe length; a radially outer surface for cooperation with an outer pipe length telescoped over the inner pipe length, and an abutment for locating the seal between the inner and outer pipe lengths, wherein the abutment extends radially inwardly of the seal body, for co-operation with the end of the inner pipe length. The inner pipe end will more consistently form a shoulder for co-operation with the seal abutment than will the outer pipe end.

The radially inner surface preferably comprises circumferential beads and the radially outer surface preferably comprises radially outwardly extending circumferential fins.

The fins are advantageously of differing radial extent, so that on insertion of the seal into the outer pipe, at least one fin is deflected by the optimum amount for sealing with a relatively large range of possible outer pipe bore sizes.

The seal may be provided with a manually graspable sleeve by which it can be drawn over the inner pipe length until the abutment seats on the end thereof. The sleeve may be engageable with a shoulder on the inner pipe length.

The abutment may be in the form of a radially inwardly extending lip which is deflectable during insertion of the inner pipe length and seal into the outer pipe length, permitting controlled passage of the inner pipe end through the seal. However, in a preferred embodiment the abutment is relatively rigid whereby the end of the inner pipe length is prevented from passing entirely through the seal during its insertion into the outer pipe length.

The invention also provides a method of installing such seals between an outer pipe length telescoped over an inner pipe length comprising the steps of: pulling the seal over an end of the inner pipe length until said end rests against the seal abutment, and inserting the seal and the inner pipe length into the bore of the outer pipe length.

The method may comprise the further step of inserting filler material between the outer pipe end, the seal and the inner pipe- length.

These and other preferred features of the invention will be apparent from the following description made by way of example and with reference to the drawings wherein: Fig. 1 is a cross-sectional view of a seal according to a first embodiment of the invention installed upon an inner pipe length; and Fig. 2 shows, on a larger scale, a part-section of a second embodiment of the invention.

Referring to Fig. 1, there is shown a seal 10 moulded from rubber or like resilient material. The seal 10 has a tubular body portion 12, whose bore is provided with circumferential beads 14 for sealing against an inner pipe length 16.

The outer surface of the body portion 12 is formed with groups 18, 20, 22 of radially extending circumferential fins 23, each group containing fins of the same radial height but with fin height increasing from group to group in the direction from the inner end of the seal 24 to the outer end 26. For a range of outer pipe bore sizes indicated schematically by the lines A, B, one group of fins 18, 20 or 22 will be deflected by close to the optimum amount so as to form the best possible seal between the inner pipe section 16 and the outer pipe section (not shown). The variation in fin height also allows for some axial misalignment between the inner and outer pipe lengths.

At its upper end 26, the seal body portion 12 is extended to form a sleeve 28 graspable by hand (for example with the sleeve 28 everted) in order to pull the seal 10 onto the end of the inner pipe length 16. The sleeve has a lipped end 29 engageable with a shoulder formed by a boss 31 of a drain casting 33 into which the inner pipe 16 is pressfitted.

To ensure correct seating of the seal 10 between the inner and outer pipe ends, the seal is provided with an abutment lip 30 at its inner end 24. The seal 10 is pulled onto the inner pipe length 16 until the lip 30 abuts the inner pipe end 32. The seal together with the inner pipe length end may then be inserted into the outer pipe length.

The sealed joint so provided between the inner and outer pipe lengths is satisfactory on its own, but may be enhanced by filler material such as polyurethane foam injected between the inner and outer pipe ends, as described in our co-pending application entitled "Drains". Tests have shown that the use of polyurethane foam filler material can increase the pressure resistance of the seal from 74 psi (52 KNm 2) to 27i psi (190 KNm#2). The seal will also serve to prevent the filler material from penetrating into the joined pipe sections.

The lip 30 is arranged to be deflectable to a position denoted 30', resistance to insertion of the inner pipe section 16 and seal 10 into the bore of the outer pipe section causing the inner pipe end 32 to move through the seal 10 to the position shown in phantom at 32'. The resistance provided by lip 30 is such that the entire seal 10 may be inserted even into the narrowest bore denoted by the lines B by pushing on the protruding end of the inner pipe section 16.

Fig. 2 shows an alternative seal 10 in which the radial height of each fin 23 progressively increases from the seal inner end to the seal outer end. The lip 30 is moulded with a relatively thick cross-section so that it does not yield to allow passage of the inner pipe end upon insertion of the inner pipe section and seal into the outer pipe section.

Claims

CLAIMS:

1. A fluid seal comprising a generally tubular body having a radially inner surface for sealing co-operation with an inner pipe length; a radially outer surface for co-operation with an outer pipe length telescoped over the inner pipe length, and an abutment for locating the seal between the inner and outer pipe lengths, wherein the abutment extends radially inwardly of the seal body, for co-operation with the end of the inner pipe length.

2. A seal as claimed in claim 1 wherein the radially inner surface comprises circumferential beads.

3. A seal as claimed in claim 1 or 2 wherein the radially outer surface comprises radially outwardly extending circumferential fins.

4. A seal as claimed in claim 3 wherein the fins are of different radial extent.

5. A seal as claimed in any preceding claim, comprising a manually graspable sleeve by which it can be drawn over the inner pipe length until the abutment seats on the end thereof.

6. A seal as claimed in claim 5 wherein sleeve is engageable with a shoulder on the inner pipe length.

7. A seal as claimed in any preceding claim wherein the abutment comprises a radially inwardly extending lip which is deflectable during insertion of the inner pipe length and seal into the outer pipe length, permitting controlled passage of the inner pipe end through the seal.

8. A method of installing a seal as claimed in any of claims 1-7 between an outer pipe length telescoped over an inner pipe length comprising the steps of: pulling the seal over an end of the inner pipe length until said end rests against the seal abutment, and inserting the seal and the inner pipe length into the bore of the outer pipe length.

9. A method as claimed in claim 8 comprising the further step of inserting filler material between the outer pipe end, the seal and the inner pipe length.

10. A fluid seal substantially as shown or described with reference to the drawings.

11. A method of installing a fluid seal as shown in the drawings and substantially as described.