GB2189000A

GB2189000A - A pipe repair or jointing collar

Info

Publication number: GB2189000A
Application number: GB08708649A
Authority: GB
Inventors: Robert William Jardine
Original assignee: E Peart and Co Ltd
Current assignee: E Peart and Co Ltd
Priority date: 1986-04-11
Filing date: 1987-04-10
Publication date: 1987-10-14
Also published as: GB8708649D0; GB2189000B

Abstract

A pipe repair or jointing collar adapted to provide an adequate seal around a damaged gas pipe or water pipe or to join two such pipe ends together, comprising a pair of arcuate segments (10) adapted to be clamped by bolts (12) around the pipe with interposition of a pair of generally semi-circular sealing members (13) with circumferential and longitudinal sealing strips (14, 15, 16). Wedges (17) fitted to each end of each sealing member (13) and bearing upon tangential sliding surfaces of segments (10), are forced to slide inwards on those surfaces as the segments are drawn together during closure thus forcing the sealing means inwards in those regions and ensuring a substantially uniform sealing effect around the pipe surface. <IMAGE>

Description

SPECIFICATION A pipe repair or jointing collar THIS INVENTION is concerned with split collars for repairing and jointing pipes such as gas pipes and water pipes.

Repair collars for this purpose take many different forms. Usually they must be designed to correspond very closely with the outer diameter of the pipes to be joined thus to ensure a watertight or gas tight seal. Since the collars are designed to be fitted to existing underground mains some of which can be 100 years old or more, it is very difficult to ensure that it will always provide an adequate seal.

Owing to changing standards, materials, manufacturing techniques and corrosion, pipes of the same nominal diameter can vary widely in actual diameter. Therefore, it is desired that the repair collar should be able to accomodate wide variations and differences in pipe diameter.

One known form of repair collar designed for this purpose comprises a plurality of arcuate segments whose abutting end faces are inclined with respect to a diametral plane of the collar so that as the segments are drawn together the respective inclined faces undergo relative sliding movement thus squeezing the pipe at a plurality of positions around its circumference. This requires sufficient resilience or flexibility in the material from which the segments are made so that they may be deformed inwardly to define a smaller radius.

However, since this kind of arrangement does not ensure a uniform reduction throughout the circumference, certain zones remain in which inadequate sealing is provided.

An object of the present invention is to provide a pipe repair or jointing collar which is capable of accomodating a range of pipe diameters but wherein an adequate seal is ensured throughout the entire circumference of the pipe to be repaired.

According to the present invention there is provided a pipe repair or jointing collar comprising a plurality of arcuate segments with clamping means for drawing the segments together around a damaged pipe or a pair of pipe ends, with interposition of one or more corresponding elastomeric arcuate sealing means, characterised by wedge-like members located between the segments and at least a part of the sealing means in the regions of the clamping means and adapted to slide generally tangentially with respect to the segments as the latter are drawn together, thus to force the sealing means radially inwards in said regions.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is an exploded view of the essential parts of a pipe repair or jointing collar; and Figure 2 is a sectional view taken along line Il-Il of Fig. 1.

A pipe repair or jointing collar in accordance with the invention includes a pair of semicylindrical segments of cast iron or a similar material having a life expectancy of 50 years when placed underground. Each segment 10 has at each end thereof a pair of radially directed bolt-receiving lugs 11 for drawing the segments together by means of bolts 12.

Each segment 10 receives an elastomeric sealing member generally indicated at 13 and consisting of circumferential ribbed sealing strips 14 and longitudinal ribbed sealing strips 15 and 16. Strips 16 serve to join adjacent ends of the circumferential strips 14, whilst strips 15 also extend between the latter but at circumferential positions spaced from their ends.

Adjacent each pair of radial lugs 11 and disposed between the body of the segment in this region and the adjacent part of the sealing member 13 is a sliding wedge-like member 17. As can be seen from the lower part of Fig. 1, each wedge 17 is retained in position on its associated segment 10 by means of the arcuate sealing strips 14 and the longitudinal sealings strips 15 and 16 with the strips located in respective channels in the wedge.

Internally protruding ribs 18 integral with segments 10, serve to prevent the longitudinal movement of the sealing members 13 and wedges 17.

As can be seen from Fig. 2 each wedge 17 slidingly abuts a generally tangential inner face of the segment 10. By this means, as the segments are drawn together by bolts 12, after initial contact of raised abutting surfaces 20 of arcuate sealing strips 14, and after initial contact of corresponding longitudinal strips 16, further closure of the segments 10 will cause the wedges 17 to slide generally tangentially with respect to the segments thus to force the sealing members radially inwards in the regions of the radial lugs 11. Thus, as depicted in Fig. 2 as the collar closes onto the pipe (not shown) along the X-X axis, so also do the wedges 17 force the sealing members 13 inwards at right angles along the Y-Y axis. Thus there is a substantially uniform reduction in diameter around the pipe to ensure a good seal thereon substantially without deformation of the segments themselves.

For example, on a nominal 150mm diameter pipe, the range of actual diameters which may be accomodated whilst providing an effective seal is at least 20 mm.

For ease of assembly the wedges 17 may be loosely retained relative to the segments 10 by rubber retaining straps 22 frictionally located on pegs 23 projecting from the sides of segments 10. Each strap 22 has a project ing pip 24 which is received within a corre spondingly shaped recess 25 in the associated end face of wedge 17. Movement of the wedges during closure, is accomodated by the resilient nature of lugs 24.

To ensure uniform tangential and radial movement of all wedges during closure, each wedge has oppositely inclined ramp surfaces 26 at its end, which interengage with those of the opposite wedge to prevent the wedges from slipping out of line.

As can be seen from Fig. 2, one or both segments of the collar can be bored as at 21 to provide a T-connection.

The collar may be of any required length with any number of fastening bolts, and it may serve as a clamp with physical properties to anchor the pipes against longitudinal movement, in addition to its role as a sealing device.

The wedges can be made from cast iron or solid rubber, or any other material which will slide with respect to the inner surfaces of the segments. In addition, whilst a straight sliding path has been depicted, this may be slightly curved about the collar axis.

One of the principal advantages of a collar produced in accordance with the invention when compared with one whose segmental walls are intended to deform is that in the present case the segments can be made of a very rigid and durable material, since substantially no deformation of the segments is required.

The invention may be applied also to socalled "full seal clamps" where a resilient sealing gasket in one or more pieces, is wrapped around a damaged pipe to form a sleeve retained in two or more arcuate clamping segments similar to segments 10 drawn together to force the sleeve into sealing contact with the outer surface of the pipe.

In this case, as in the previous embodiment, wedge-like members are provided between the sealing sleeve and the clamping segments, and slide tangentially as the segments are tightened thus to force the sleeve radially inwards in that region.

In some cases, with this embodiment the wedges may be of hollow section and the segments may be afforded a degree of flexibility to enable them to conform to the actual size of the pipe and its shape in cases where the pipe has become deformed from a circular cross-section.

Claims

1. A pipe repair or jointing collar comprising a plurality of arcuate segments with clamping means for drawing the segments together around a damaged pipe or a pair of pipe ends, with interposition of one or more corresponding elastomeric arcuate sealing means, characterised by wedge-like members located between the segments and at least a part of the sealing means in the regions of the clamping means and adapted to slide inwardly and generally tangentially with respect to the segments as the latter are drawn together, thus to force the sealing means radially inwards in said regions.

2. A pipe repair or jointing collar wherein said arcuate sealing means for each segment comprises a pair of ribbed circumferential sealing strips spaced apart axially by two pairs of ribbed circumferential sealing strips integral with said circumferential strips, the latter and said longitudinal sealing strips locating within respective channels in said wedge-like members.

3. A pipe repair or jointing collar according to Claim 1, wherein the arcuate segments include internally protruding abutments which serve to retain the sealing members and wedges in position.

4. A pipe repair or jointing collar according to Claim 1, in which each wedge-like member slidingly abuts a generally tangential inner face of a respective arcuate segment.

5. A pipe repair or jointing collar according to Claim 4, wherein each said generally tangential inner face is slightly curved about the central longitudinal axis of the collar.

6. A pipe repair or jointing collar according any preceding claim, including resilient retaining straps frictionally engaging the arcuate segments and the wedge-like members thus to retain the assembly thereof during closure of the collar.

7. A pipe repair or jointing collar according to any preceding claim, in which each wedgelike member has oppositely inclined ramp surfaces at its ends respectively, positioned and arranged to inter-engage with those of the respective opposite wedge-like member to prevent said members from slipping out of line during closure of the collar.

8. A pipe repair or jointing collar according to Claim 1, wherein said sealing means comprises a resilient gasket composed of one or more pieces to be wrapped around a damaged pipe to form a sleeve, and wherein said wedge-like members are of hollow section.

9. A pipe repair or jointing collar according to Claim 8, wherein the arcuate segments are afforded to a degree of flexibility to enable them to conform to the actual size of a pipe and to its shape in cases where the pipe has become deformed from a circular cross-section.

10. A pipe repair or jointing collar substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.