GB2340569A

GB2340569A - A method of joining adjacent end portions of aligned pipes

Info

Publication number: GB2340569A
Application number: GB9817444A
Authority: GB
Inventors: Raymond Edward Johnson
Original assignee: BARNARD Ltd; BARNARD PIPELINE Ltd
Current assignee: BARNARD Ltd; BARNARD PIPELINE Ltd
Priority date: 1998-08-12
Filing date: 1998-08-12
Publication date: 2000-02-23
Also published as: GB9817444D0

Abstract

A method of joining adjacent end portions of generally longitudinally aligned pipes 1, 2 using a sleeve 3, having end portions in which are formed outwardly open-ended housings 3A for receiving respective resilient sealing rings 6. The method comprises placing the sealing rings respectively around the pipe end portions, and then arranging the sleeve to bridge between and surround the adjacent pipe end portions within the axial positions occupied by the sealing rings. The sealing rings are then forced into the respective sleeve housings so as to resiliently compress the rings radially between the internal surfaces of the housings and the outer surfaces of the pipe end portions so that they constitute self sustaining seals between these surfaces. Retaining means are positioned to retain the seals within the housings, which may be in the form of two end members 5 connected together by tie bolts 9 carried by and extending between the end members, and where each end member may be a one-piece plastics moulding.

Description

2340569 PIPE JOINING This invention relates to a method of joining

together, in fluid-tight manner, the adjacent end portions of generally longitudinally aligned pipes and to a composite pipe formed by a pair of pipes joined together by the aforesaid method.

In one known form of pipe joining arrangement, a sleeve is used to bridge across the adjacent pipe end portions and a pair of seal rings respectively surrounding the pipe end portions are compressed between clamping members and the sleeve to force the seal rings against the pipe surface and thereby effect a leak-tight joint. With such an arrangement, the effectiveness of the seal is dependent upon the force applied by the clamping members, which are required to be robust and sufficiently reliable to maintain a high integrity seal over a long period. The known arrangement has the disadvantages of being both expensive, and vulnerable to damage, with an attendant risk of leakage of the pipe contents should the effectiveness of the seal be compromised.

In another known arrangement, a sleeve isprovided with a socket in which a seal is housed and retained longitudinally and initially projects radially of the housing into the sleeve interior, and a pipe is connected to the sleeve by inserting it into the sleeve end and forcing it past the seal so that the latter is radially compressed into the housing and forms a seal between the pipe and sleeve. Although this arrangement produces a satisfactory seal, it has the disadvantage that it is difficult to gain access to the seal, for example to replace it, once the assembled pipe and socket are incorporated in the larger pipe structure, such as a pipeline.

An object of the invention is to provide an improved pipe joining method and a composite pipe formed by a pair of pipes joined together by the aforesaid method, in which the aforesaid drawbacks are alleviated or avoided.

According to the invention, a method of joining together the adjacent end portions of generally longitudinally aligned pipes using a sleeve in the end portions of which are formed outwardly open-ended housings for the reception of respective resilient sealing rings, the method comprising placing the sealing rings respectively around the pipe end portions, arranging the sleeve to bridge between and surround the adjacent pipe end portions within the axial positions occupied by the sealing rings, forcing the sealing rings into the respective sleeve housings in such a manner as resiliently to compress the rings radially between the internal surfaces of the housings and the outer surfaces of the pipe end portions so that the rings then constitute self-sustaining seals between said surfaces, and positioning respective retaining means to retain the seals within the housings.

Preferably, the retaining means are arranged to engage respective abutment surfaces of the sleeve, which may conveniently be end surfaces of the sleeve. Conveniently, the retaining means are brought into engagement respectively with the sealing rings.

From another aspect of the invention, a composite pipe made by joining together the adjacent end portions of generally longitudinally aligned pipes by carrying out the aforesaid method, comprises a sleeve bridging between and surrounding the adjacent pipe end portions and having, in its end portions, outwardly open-ended housings, and respective sealing rings located within the sleeve housings and resiliently compressed between the internal surfaces of the housings and the outer surfaces of the pipe end portions to constitute self-sustaining seals between said surfaces, and retaining means serving to retain the seals within the housings.

The retaining means are preferably arranged to engage respective abutment surfaces of the sleeve.. which may conveniently be end surfaces thereof. The retaining means may respectively engage the sealing rings.

The invention will now be described, by way of example, with reference to the accompanying drawings in which:- Figure 1 is an exploded view illustrating a stage in the joining of a pair of pipes according to the method of the invention., and Figure 2 illustrates a composite pipe formed by carrying out the pipe joining method of the invention.

The arrangement illustrated in Figure 1 includes a pair of longitudinally aligned pipes 1 and 2 which it is intended to join together by carrying out the method of the invention. The adjacent opposed end portions of the pipes are shown inserted within a sleeve 3 which consists of a central cylindrical portion 4, of which the internal diameter is only slightly greater than the external diameter of the pipes. The free end portions of the sleeve 3 are of enlarged diameter and form sockets 3A, the mouths of which are flared at 3B. Prior to placing the sleeve 3 in its illustrated position, respective end members 5 are placed around the pipes 1 and 2 and respective seals 6 are placed around the pipes forwardly of the end members, in directions towards of the pipe ends.

Each end member 5 has a radially extending flange 7 provided with an aperture 8 to receive therethrough a tie bolt 9, as illustrated at the left hand side of Figure 1. The tie bolt will be similarly connected to the right hand end member 5 and secured to the flanges by respective nuts 9A. The end members also have a generally axially extending collar 10 having an angled internal surface 11, for the purpose to be described.

Each seal 6 has a maximum radial dimension, in the condition illustrated in Figure 1, which is slightly greater than the diameter of the internal wall 3C of its associated socket 3A. The seal portion 6A having the aforesaid maximum dimension has a generally rounded external surface leading to a rearwardly extending tapered or bevelled portion 6B. The seals are illustrated diagrammatically as one-piece items, but may, in practice, include a relatively rigid annular base which fits closely around a pipe outer periphery and a relatively flexible seal portion carried on the base.

With the various components arranged in the manner illustrated in Figure 1, the method of the invention is carried out in the following manner in order to join together the pipes 1 and 2 in fluid-tight manner to form the composite pipe illustrated in Figure 2. The first step is to insert the seals 6 within the sleeve sockets 3A. Substantial force is required to compress the seals within the sockets and this may conveniently be achieved by employing the clamping action of the ties 9 inserted through the holes 8 of the members 5 and the nuts 9A engaged thereon. The seals 6 are conveniently placed as close as possible to the mouths of the sockets 3A and the end members 5 moved along the pipes until the collars 10 engage the surfaces 613 of the sleeves. By tightening the nuts, the members 5 are moved towards each other and apply sufficient force to the seals 6 to force them into the sockets 3A and compress them radially between the outer surfaces of the pipes and the internal surfaces 3C of the sockets. Tightening of the nuts 9A is continued until the components reach the positions shown in Figure 2.

Figure 2 illustrates the composite pipe formed by joining together the pipes 1 and 2 in fluid-tight manner. It will be seen that the nuts 9A are tightened to an extent which brings the flanges 7 into engagement with the end surfaces of the sleeve 3, which limits the amount of compressive force applied to the seals. The collars 10 are firmly engaged with the seals 6 to retain these in position within the sockets. It will be understood that the sealing force is provided by radial compression of the seals, which has already taken place, and the members 5 are not required to exert a continuing large force on the seals. The members 5 may conveniently be moulded integrally from plastics material or may be composite devices having, for example, flanges 7 of metal and collars 10 of a different material, such as plastics, which may either be bonded to the flanges 7 or used as separate components.

Whilst the method of the invention has been described as applied to the simple joining together of two longitudinally aligned pipes, it may be used in an existing pipeline when it is required to insert therein an additional component such as a T-junction for example. The existing pipe would then be divided and a section thereof removed to permit the additional component to be inserted with tubular members thereof aligned with the existing pipe ends. This would require the employment of two sleeves, each with its attendant pair of seals and clamping arrangement and each would be used in the manner described above to connect the existing pipe end portions to the additional component in fluid-tight manner.

The method of the invention and the resultant composite pipe formed thereby has the significant advantage that, by loosening the nuts 9A and removing the end members 5, it is possible to gain access to the seals 6 for inspection or replacement of the latter.

Claims

1. A method of joining together the adjacent end portions of generally longitudinally aligned pipes using a sleeve in the end portions of which are formed outwardly open-ended housings for the reception of respective resilient sealing rings, the method comprising placing the sealing rings respectively around the pipe end portions, arranging the sleeve to bridge between and surround the adjacent pipe end portions within the axial positions occupied by the sealing rings, forcing the sealing rings into the respective sleeve housings in such a manner as resiliently to compress the rings radially between the internal surfaces of the housings and the outer surfaces of the pipe end portions so that the rings then constitute selfsustaining seals between said surfaces, and positioning respective retaining means to retain the seals within the housings.

2. A method as claimed in Claim 1, comprising employing the respective retaining means to force the sealing rings into the respective sleeve housings to form said self-sustaining seals.

3. A method as claimed in Claim 2, wherein said force is provided by drawing towards each other two end members forming said retaining means by tightening nut means on a tie bolt carried by and extending between said end members.

4. A method as claimed in Claim 3, wherein prior to applying said 'force, the sealing rings are placed as close as possible to respective mouths of the housings and said end members moved along the pipes until respective collars of the end members engage respective surfaces of the sealing rings.

5. A method as claimed in any one of the preceding claims, wherein when retaining the seals within the housings, the respective retaining means are positioned to engage respective abutment surfaces of the sleeve.

6. A method as claimed in Claim 5, wherein the abutment surfaces are respective end surfaces of the sleeve.

7. A method as claimed in any one of the preceding claims, wherein in the retained positions of the respective seals, the respective retaining means engage the respective seals.

8. A composite pipe made by joining together the adjacent end portions of generally longitudinally aligned pipes, comprising a sleeve bridging between and surrounding the adjacent pipe end portions and having, in its end portions, outwardly open-ended housings, and respective sealing rings located within the sleeve housings and resiliently compressed between the internal surfaces of the housings and the outer surfaces of the pipe end portions to constitute self-sustaining seals between said surfaces, and retaining means serving to retain the seals within the housings.

9. A pipe as claimed in Claim 8, wherein the retaining means are arranged to engage respective abutment surfaces of the sleeve.

10. A pipe as claimed in Claim 9, wherein the abutment surfaces of the sleeve are end surfaces thereof.

11. A pipe as claimed in any one of Claims 8 to 10, wherein the retaining means respectively engage the sealing rings.

12. A pipe as claimed in Claim 11, wherein the retaining means includes two end members, each of which has an angled internal surface which engages a tapered surface of the sealing ring.

13. A pipe as claimed in any one of Claims 8 to 11, wherein the retaining means are in the form of two end members connected together by a tie bolt carried by and extending between said end members, with nut means on the tie bolt to hold the end members drawn together to retain the seals within the housings.

14. A pipe as claimed in Claim 13, wherein each end member is formed with a radial flange and a generally axially extending collar, an aperture provided in said flange receiving said tie bolt therethrough.

15. A pipe as claimed in any one of Claims 8 to 14, wherein each sealing ring has a relatively rigid annular base and a relatively flexible seal portion carried on the base.

16. A pipe as claimed in any one of Claims 12 to 14, wherein each of the end members is a one-piece plastics moulding.

17. A pipe as claimed in any one of Claims 8 to 11, wherein the retaining means include respective end members, each of which is of composite form, having a radial flange and a generally axial collar.

18. A pipe as claimed in Claim 17, wherein the flange and collar are separate components.

19. A composite pipe as produced by the method of any one of.Claims 1 to 7.

20. A method of joining together the adjacent end portions of longitudinally aligned pipes, substantially as hereinbefore described, with reference to. and as shown in the accompanying drawings.

21. A composite pipe made by joining together the adjacent end portions of longitudinally aligned pipes, substantially as hereinbefore described. with reference tof and as shown in the accompanying drawings.