GB2314393A

GB2314393A - Coupling comprising elastomeric strip clamped around pipe ends or fracture

Info

Publication number: GB2314393A
Application number: GB9711914A
Authority: GB
Inventors: Timothy Richard Sykes
Original assignee: Flex Seal Couplings Ltd
Current assignee: Flex Seal Couplings Ltd
Priority date: 1996-06-20
Filing date: 1997-06-10
Publication date: 1997-12-24
Anticipated expiration: 2017-06-10
Also published as: GB2314393B; GB9711914D0; GB9612977D0; DE29710213U1

Abstract

The coupling, particularly for repair purposes, comprises the elastomeric material strip (10) having on one face pairs of ribs (11, 12) for location of clamping bands (15, 16), sealing ribs (17) along the longitudinal edges of the other face, transverse sealing ribs at the ends extending between and merging with the longitudinal sealing ribs (17), complementary profiled edges (19A, 19B), e.g.of wedge and complementary V-groove form, at the ends of the strip (10), and a bridging member (20) to span the join formed by the mating edges (19A, 19B), whereby sealing takes place between those mating edges and also between the longitudinal and transverse sealing ribs (17, 18A, 18B) and a pipe, clamping pressure being applied across the join by the clamping bands (15, 16) through the bridging member (20). The bridging member (20) has inward tabs (25), locating in slots in the strip, or has arms with end holes engaged by pins in the strip.

Description

PIPE COUPLINGS It is known to use a pipe coupling consisting of an elastomeric sleeve with external clamping bands to join two pipes. The pipes may be of similar material as in the case of installation of a new pipe system or dissimilar materials as in the case ofjoining new pipes to old.

Differences of up to 16 mm in diameter between the two pipes may be accommodated. A leaktight seal is formed by tightening the clamping bands fitted between ribs at the ends of the sleeve within which there are circumferential sealing ribs. Resistance to shear acting on the join is provided by a central clamping band round the mid-portion of the sleeve which spans the gap between the two pipes and is tightened down during installation. As well as joining pipes during new installation these couplings may be used to repair a pipe that has become damaged i.e. holed or cracked. In this case, if the damage is severe, it is necessary to cut out the damaged section and replace it with a new piece of pipe, using two couplings to join the new piece to the old pieces. If the damage is such that the crack or cracks extends axially along the pipe by less than the distance between the two circumferential sealing ribs of a coupling, or is a hole or holes or a combination of cracks and holes positioned such that it occupies or they occupy an axial length less than the distance between the two circumferential sealing ribs of a coupling, the damage can be repaired by securing a coupling over the damaged area. This will make the pipe both watertight again and add strength to an otherwise weakened area of the pipe. In many situations, however, installation of a coupling is rendered impracticable as fitting the coupling requires a free end of pipe. In such a situation a repair coupling that may be installed by wrapping around the pipe would be advantageous.

The object of the invention is, therefore, to provide a wrap-around pipe coupling with means for effecting secure and efficient sealing especially round a damaged area of a pipe in situ.

According to the present invention, a wrap-around pipe coupling, particularly - but not exclusively - for repair purposes, comprises a strip of elastomeric material having on one face two pairs of ribs defining a groove adjacent each longitudinal edge of the strip and a broader central groove between the inner pair of ribs, a pair of wrap-around clamping bands for location in the edge grooves and a broader wrap- around clamping band for location in the central groove after the strip has been wrapped around a pipe, a pair of longitudinal sealing ribs along the other face of the strip opposite the edge grooves, a transverse sealing rib adjacent each end of the strip extending between and merging with the longitudinal sealing ribs, the ends of the strip being provided with complementary profiled edges for mating engagement when the strip is wrapped around a pipe, and a bridging member to span the join formed by the mating strip ends underneath the clamping bands.

The clamping bands may be of the type secured and tightened by screw devices or of the type secured and tightened by toggle levers.

Sealing takes place between the mating complementary profiled end edges of the strip, and also between the longitudinal and transverse sealing ribs and the pipe, clamping pressure being applied across the join by the clamping bands through the bridging member.

The complementary profiled edges of the ends of the strip may consist of a wedge-section across one strip end and a V-groove across the other strip end; and the transverse sealing ribs and the complementary profiled edges may be formed in initially separately moulded elastomeric members subsequently bonded to an appropriate length cut from an elastomeric extrusion having a uniform cross-section including the pairs of longitudinal ribs along one face (for location of the clamping bands) and the longitudinal sealing ribs along the other face. The extrusion and the moulded members may have a thinner section between the inner pair of ribs than between each outer pair of ribs, to afford greater flexibility under the broader central clamping band.

The bridging member may be formed of metal (e.g., stainless steel) strip or it may be moulded in "rigid" plastics, with a pair of corrugations to fit over the inner pair of ribs. The bridging member is preferably provided with means for engaging with the ribs so as to hold the bridging member in place and also to hold the mating strip ends together while the clamping bands are being applied; thus the inner pair of ribs may be provided with headed pins embedded therein adjacent the ends, and the bridging member provided with holes for fitting over the heads of the pins when the complementary profiled edges are pushed into close mating engagement with each other; alternatively, the corrugations of the bridging member may be provided with down-turned tabs to engage in grooves in the inner pair of ribs of the mating strip ends.

An embodiment of the invention and a modification thereof will now be described, by way of example only, with reference to the accompanying drawings, in which Figure 1 is a side elevation of a pipe coupling in accordance with the invention; Figure 2 is a fragmentary side elevation in the region and direction of the arrow II in Figure 1; Figure 3 is a section on the line III-III of Figure 2; Figure 4 is a fragmentary view in the direction ofthe arrow IV in Figure 3; Figure 5 is an exploded fragmentary perspective view of the novel features of the invention; and Figure 6 corresponds to Figure 5 but shows a modification thereof.

In Figures ] to 5, a wrap-around pipe coupling comprises a strip 10 of elastomeric material having on one face two pairs of ribs 11, 12 defining a groove 13 adjacent each longitudinal edge of the strip and a broader central groove 14 between the inner pair of ribs 12, a pair of wrap-around clamping bands 15 for location in the edge grooves 13 and a broader wraparound clamping band 16 for location in the central groove 14 after the strip has been wrapped around a pipe (not shown), a pair of longitudinal sealing ribs 17 along the other face of the strip opposite the edge grooves 13, a transverse sealing rib 18A, 18B adjacent each end of the strip extending between and merging with the longitudinal sealing ribs 17, the ends of the strip being provided with complementary profiled edges 1 9A, 1 9B for mating engagement when the strip is wrapped around a pipe, and a preferably stiff bridging member 20 to span the join formed by the mating strip ends underneath the clamping bands 15, 16.

The clamping bands are shown with screw tightening devices 21, but they may alternatively be provided with toggle levers.

Sealing takes place between the mating complementary profiled end edges 19A, 19B of the strip 10, and also between the longitudinal and transverse sealing ribs 17, 1 SA, 18B and a pipe around which the strip is wrapped, clamping pressure being applied across the join by the clamping bands 15, 16 through the bridging member.

The complementary profiled edges l9A, 1 9B of the ends of the strip 10 consist of a wedge-section 1 9A across one strip end and a V-groove across the other strip end; and the transverse sealing ribs 18A, 1 SUB and the complementary profiled edges 19A, 1 9B are formed in initially separately moulded elastomeric members 22A, 22B bonded along planes 23A, 23B (see Figure 5) to an appropriate length cut from an elastomeric extrusion having a uniform crosssection including the pairs of longitudinal ribs 11, 12 (for location of the clamping bands 15, 16) and the longitudinal sealing ribs 17. The extrusion and the moulded members 22A, 22B have a thinner section between the inner pair of ribs 12 than between each outer pair of ribs, to afford greater flexibility under the broader central clamping band 16.

The bridging member 20 is conveniently formed of stainless steel strip, but it may alternatively be moulded in "rigid" plastics, with a pair of corrugations 24 to fit over the inner pair of ribs 12. The corrugations are provided with down-turned tabs 25 to engage in grooves 26 in the inner pair of ribs 12 of the mating strip ends (see particularly Figure 5) to hold the bridging member 20 in place and also to hold the mating strip ends together while the clamping bands 15, 16 are being applied. Alternatively, as shown in Figure 6, the inner pair of ribs 12 are provided with headed pins 27 embedded therein adjacent the ends, and the bridging member 20 is provided with holes 28 (in cross-strips 29 spot-welded or otherwise bonded to the corrugations) for fitting over the heads of the pins when the complementary profiled edges 1 9A, 1 9B are pushed into close mating engagement with each other.

Claims

1. A wrap-around pipe coupling comprising a strip of elastomeric material having on one face two pairs of ribs defining a groove adjacent each longitudinal edge of the strip and a broader central groove between the inner pair of ribs, a pair of wrap-around clamping bands for location in the edge grooves and a broader wrap-around clamping band for location in the central groove after the strip has been wrapped around a pipe, a pair of longitudinal sealing ribs along the other face of the strip opposite the edge grooves, a transverse sealing rib adjacent each end of the strip extending between and merging with the longitudinal sealing ribs, the ends of the strip being provided with complementary profiled edges for mating engagement when the strip is wrapped around a pipe, and a bridging member to span the join formed by the mating strip ends underneath the clamping bands.

2. A wrap-around pipe coupling as in Claim 1, wherein the complementary profiled edges of the ends of the strip consist of a wedge-section across one strip end and a V-groove across the other strip end.

3. A wrap-around pipe coupling as in Claim 1 or Claim 2, wherein the transverse sealing ribs and the complementary profiled edges are formed in initially separately moulded elastomeric members subsequently bonded to an appropriate length cut from an elastomeric extrusion having a uniform cross-section including the pairs of longitudinal ribs along one face and the longitudinal sealing ribs along the other face.

4. A wrap-around pipe coupling as in Claim 3, wherein the extrusion and the moulded members have a thinner section between the inner pair of ribs than between each outer pair of ribs, to afford greater flexibility under the broader central clamping band.

5. A wrap-around pipe coupling as in any one of Claims 1 to 4, wherein the bridging member is formed of metal strip or moulded in "rigid" plastics, with a pair of corrugations to fit over the inner pair of ribs.

6. A wrap-around pipe coupling as in any one of Claims 1 to 5, wherein the bridging member is provided with means for engaging with the ribs so as to hold the bridging member in place and also to hold the mating strip ends together while the clamping bands are being applied.

7. A wrap-around pipe coupling as in Claim 6, wherein the inner pair of ribs are provided with headed pins embedded therein adjacent the ends, and the bridging member provided with holes for fitting over the heads of the pins when the complementary profiled edges are pushed into close mating engagement with each other

8. A wrap-around pipe coupling as in Claim 6, wherein the corrugations of the bridging member are provided with down-turned tabs to engage in grooves in the inner pair of ribs of the mating strip ends.

9. A wrap-around pipe coupling substantially as hereinbefore described with reference to the accompanying drawings.