GB2365094A

GB2365094A - Device for sealing a leak in a plastic pipe

Info

Publication number: GB2365094A
Application number: GB0017469A
Authority: GB
Inventors: Anthony Frederick Douglas; Peter Michael Wardle
Original assignee: Chemence Ltd
Current assignee: Chemence Ltd
Priority date: 2000-07-18
Filing date: 2000-07-18
Publication date: 2002-02-13
Anticipated expiration: 2020-07-18
Also published as: GB2365094B; GB0017469D0

Abstract

A device is provided for sealing a leak 4 in a plastic pipe 1, the device comprising a patch 2 having a body of flexible material for adhesion to the surface of the pipe over the leak 4 and patch reinforcement means 3 arranged in such a way as to inhibit flexing of the patch body 2 in a direction transversely of the longitudinal axis of the pipe 1 when the patch 2 has been appropriately secured to the surface of the pipe 1. The patch reinforcement means 3 are preferably embedded in the patch 2, and may comprise steel strips 3. Additional securing straps 6, 7 may be provided.

Description

<Desc/Clms Page number 1> Device for Seah a Leak 'in a Plastic Pi e The present invention relates to a device for sealing a leak or a potential leak 'in a plastic pipe.

Over the last 20 years or so gas companies and the water compaiiiies have pursued a programme of replacing existing cast iron and steel pipes which carry gas or water and earthenware sewer pipes with plastic based replacements. In addition all new mains laid have been of plastic with the most popular new pipe material being polyethylene (pe) because of its relatively low cost and high durability.

Due to continuing excavation for such purposes as laying television cables, repairs to adjoining services and other reasons, these pe pipes are frequently damaged by excavating machinery and other tools, are punctured and develop leaks.

Attempts have been made to repair or stop the leak by applying a device in the form of a patch to the pipe surface over the puncture to seal it in the manner of a bicycle inner tube repair. However these attempts have not been very successful as the pressure of the gas or water has a tendency to cause the patch to bow out from the pipe and eventually to break free of the pipe.

Accordingly it is an object of the present invention to provide an improved device for sealing a leak in a plastic pipe.

According to the present invention a device is provided for sealing a leak in a plastic pipe, the device comprising a patch having a body of flexible material for adhesion to the surface of the pipe over the leak and patch reinforcement means arranged in such a way as to inhibit flexing of the patch body in a direction transversely of the longitudinal axis of the pipe when the patch has been appropriately secured to the surface of the pipe. Preferably, the patch reinforcement means is embedded in the body of the patch. Suitably, the patch reinforcement means comprises a plurality of elongate members of a material more rigid than the material of the patch body and conveniently, the members

are spaced apart from each other but aligned in parallel with each other, whereby when the patch is to be secured to the surface of the pipe, the members can be aligned with the longitudinal axis of the pipe.

Converuiently, each member is of metal, preferably steel and suitably stainless steel. The patch body may be made of rubber or elastomeric rubber e.g. polyurethane. Preferably, means are provided to strap the patch to the pipe.

Suitably, the patch has ribs on the side of the patch which is to engage the pipe, the ribs being arranged to form channels between the pipe surface and the non-ribbed surface of the patch when the patch is located on the pipe, the channels providing flow paths for liquid adhesive.

Conveniently, the ribs are arranged in the fonn of a grid with each component of the grid forming a compartment between the pipe surface and the non-ribbed surface of the patch when the patch is located on the pipe, each rib of the grid component having a gap to permit the adhesive to flow from one compartment to another.

An embodiment of the present invention will now be particularly described with reference to the accompanying drawings in which: Figure I is a plan view of a device in accordance with one embodiment of the present invention, the device comprising a patch which has been secured to the surface of a polyethylene pipe over a leak, Figure 2 is a transverse section of a flat patch before application to the surface of a pipe, Figure 3 is a plan view of a device in accordance with another embodiment of the present invention and Figure 4 is a view along the lines IV-IV of Figure 3.

Referring to the drawings, before it is applied to the surface of the pipe 1, which *in this case is pe, the device initially comprises an oval-shaped flat patch 2 made of a rubber or rubber type composition in which are embedded a number of reinforcing or stiffening members 3 (in the drawings five such members _3 ) are shown). These members 3 are spaced apart and are aligned parallel to the longer axis of the patch 2 as shown. The :D members 3 are made of stainless steel and can be in the form of strips or rods.

The device is made in a mould by first placing the members 3 'in the mould (not shown) in the required alignment and then pouring liquid polymer or a softened rubber composition over them to the required depth so that when the polymer or rubber has solidified to form the patch 2 the members 3 have become embedded *in it.

The patch 2 so formed will be generally inflexible and rigid in a direction transverse of the longitudinal axis of the patch 2 but will be relatively flexible in a direction parallel to the longitudinal axis of the patch 1.

This means that, in use, the patch 2 can be curved transversely to conform with the curvature of a range of pipe circumferences when applied to them while at the same time the members 3 inhibit flexing of the patch 2 in a direction transverse to the longitudinal axis of the pipe 1.

To adhere the patch 2 to the surface of the pipe I over a leak (shown as a hole 4 in Figure 1), a suitably sized portion of the surface of the pipe I around the hole 4 is first of all cleaned with a primer such as iso-propanol. Then the pipe-facing side 5 of the patch 2 is smeared with a suitable adhesive which in this case is a cyanoacrylate anaerobic type glue and the patch 2 is then applied to the cleaned surface of the pipe 1, excess glue being removed.

Finally, two spaced apart retaining straps or belts 6 and 7 of a suitable durable and mechanically strong plastic material such as polyurethane are tied around the circumference of the pipe I over the patch 2 to provide further compression of the patch 2 to ensure intimate and complete bonding between the patch and the pipe, one end of each strap 6,7 having a buckle 8 and hooks (not shown) to engage with the other end of the strap 6,7 when threaded through the buckle 8 to hold the strap 6,7 in place.

Referring to Figures 3 and 4, there is shown a more sophisticated version of the patch 2. Here the side 10 of the patch 2 which is to engage the surface of the pipe is provided w I 'th a nurnber of ribs I I arranged in the form of a gri id which, in use, forms channels between the pipe surface and the non-ribbed surface 12 of the patch 2 when the patch 2 is located on the pipe. The channels provide flow paths for liquid adhesive and this has been found to improve the subsequent adhesion of the adhesive to the pipe surface by 'ding a greater degree of coverage of adhesive on the patch. Each rib I I forms provi with adjoining ribs I I a compartment 13 between the pipe surface and the non-ribbed surface 12 of the patch when the patch 2 is located on the pipe. Each rib I I of the grid has a gap 14 to perrr#t the adhesive to flow from one compartment to the other and thereby form the channels.

The patch 2 is provided with a pair of sealant injection holes 15 and 16 extending through its body to permit liquid sealant to be iiijected 'into selected compartments 13 when the patch 2 is in position on the pipe whereby the sealant can flow between compartments 13 across the patch surface. Finally, the patch 2 is also provided with a central raised thickened portion 20 of generally disc-like shape which section is to be located over the actual leak to i-npart extra strength at this point.

Compression of the patch onto the pipe restricts the flow of sealant and ensures a complete repair with full adhesion over the entire surface.

A further option is to overwrap the repair with an elastomeric adhesive tape (not shown) which adheres strongly to the pe pipe and the patch. This provides additional security in that it prevents environmental attack which would in certain circumstances cause a breakdown in the integrity of the repair.

Claims

Claims 1. A device for seating a leak in a plastic pipe, the device including a patch having a tD body of flexible material for adhesion to the surface of the pipe over the leak and patch reinforcement means arranged in such a way as to inhibit flexing of the patch body 'in a direction transversely of the longitudinal axis of the pipe when the patch has been appropriately secured to the surface of the pipe.
2. A device as claimed in claim I in which a settable liquid adhesive provides the adhesion for the patch .
3. A device as claimed in claim I or claim 2 in which the patch reinforcement means is embedded in the body of the patch.
4. A device as claimed in any of claims I to 3 in which the patch reinforcement means comprises a plurality of elongate members of a material more rigid than the material of the patch body.
5. A device as claimed in claim 4 in which the members are spaced apart from each other but aligned in parallel with each other whereby when the patch is to be secured to the surface of the pipe, the members can be aligned with the longitudinal axis of the pipe-
6. A device as claimed in claim 4 or claim 5 in which each member is of metal.
7. A device as claimed in claim 6 'in which the metal is steel.
8. A device as claimed in claim 7 in which the steel is stainless steel.
9. A device as claimed in any of the preceding claims in which the body of the patch is of rubber.
10. A device as claimed in any of the preceding claims in which means are provided to strap the patch to the pipe.

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11. A device as claimed 'in any of the preceding claims 'in which the patch has ribs on the side of the patch which is to engage the pipe, the ribs being arranged to form channels between the pipe surface and the non-ribbed surface of the patch when the patch is located on the pipe, the channels providing flow paths for liquid adhesive.
12. A device as clau'ned in claim I I in which the ribs are arranged in the form of a grid with each rib forming a compartment between the pipe surface and the non-ribbed surface of the patch when the patch is located on the pipe, each rib of the grid having a gap to permit the adhesive to flow from one compartment to another to form, the channels.
13. A device substantiafly as hereiribefore descri'bed with reference to the accompanying drawings.