GB2400898A

GB2400898A - Method and apparatus for repairing a pipe

Info

Publication number: GB2400898A
Application number: GB0309472A
Authority: GB
Inventors: Anthony O'donnell; Steven John Davis
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-04-25
Filing date: 2003-04-25
Publication date: 2004-10-27

Abstract

A pipe liner 8 is deformed and held within a carrier member 12. The deformed pipe liner 8 is held in the carrier member 12, and a force is applied to the carrier member to position it within a pipe 2 to be repaired. The carrier member 12 is then withdrawn from the pipe 2, leaving the pipe liner 8 inserted within the pipe. The pipe liner 8 is then expanded to form a lining on the pipe 2. The carrier member 12 may be formed from a plurality of individual members (16, figure 2). The pipe liner 8 may be retained in position within the pipe 2 during removal of the carrier member 12 by a radially expandable fixing member (8, figure 4). The carrier member 12 may have a slot 14 extending along its length through which the pipe liner 8 can be inserted.

Description

METHOD AND APPARATUS FOR REPAIRING A PIPE

The present invention relates to a method and apparatus for repairing a pipe and particularly, but not exclusively, to a method and apparatus for repairing a domestic subterranean water supply pipe.

Domestic and industrial services such as water and gas supplies have, for many years, been run in subterranean pipelines made of plastics materials. The use of plastics materials in running these types of pipeline has proven to be a convenient and cost effective means of running services to housing and industrial properties. However, particularly in the water industry, there remains a large number of water supply lines which comprise relatively old non-plastics pipe work (for example, metallic or concrete pipelines) which have degraded with age and now leak to such an extent as to be almost unserviceable.

It is a known technique in the water industry to renew traditional pipelines by running new pipe work (typically of a polyethylene material) within the existing pipeline.

More specifically, access to the original pipeline is gained by excavating in the region of the pipeline and removing a section thereof. Pre-welded polyethylene (PE) pipe is then pushed through a forming device which folds the pipe into a heart shape (in cross- section). In order to prevent the folded pipe from expanding into its original circular cross-section, restraining bands are temporarily secured about the pipe exterior surface.

The reduced cross-section of the folded pipe creates a clearance so as to facilitate installation of the pipe into the original pipe work. Once the folded PE pipe has been pushed through the original pipe work and is located in position, the interior of the new pipe work is pressurised with water so as to break the temporary restraining bands and force the folded pipe work into its circular form. The new pipe work is then ready to receive and convey a supply of water.

It will be understood that the above described system uses the existing pipe work as a conduit for guiding the new run of pipe work. The new pipe work is itself structurally independent of the original pipe work and, once the new pipe work is in place, the original pipe work may continue to degrade and collapse about the new pipe work without affecting the water supply line.

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Although the aforementioned system is of use in renewing a mains supply, it is unsuitable for addressing leaks in the relatively small diameter supply pipes typically found extending from the mains stop-cock to a house or other small property. lithest supply lines will generally have an inner diameter of approximately 15mm to 25mm and it will be understood therefore that a replacement pipe to be pushed within such an existing pipeline will tend to have a wall thickness to outer diameter ratio which (for a polyethylene material) does not permit a ready folding so as to reduce cross-section in accordance with the prior art system described. Thus, although the above described prior art system has been in use for many years in connection with the renewing of degraded supply pipelines, the problem of repairing small diameter supply lines extending from a mains stop-cock has herein before now been solved by excavating the full length of the small diameter supply line and repairing and/or replacing pipe work as necessary. It will be appreciated however that this procedure is expensive, time consuming and extremely inconvenient inasmuch as excavation may be required of, for example, garden or patio areas. Indeed, unless the entire pipeline is excavated, there is a risk that one damaged section will be repaired with the expectation of having completely salved a leaking problem, only for further leaks to become subsequently evident. This will necessitate further excavation and further expense and inconvenience.

It is an object of the present invention to provide an improved method and apparatus for repairing pipe work.

A first aspect of the present invention provides a method of repairing a pipe, the method comprising the steps of exposing an access to the interior of the pipe; locating a pipe liner in a deformed condition in which the pipe liner is resiliently deformed along its length so as to have a reduced transverse dimension; inserting the pipe liner into the pipe via said access whilst the pipe liner is in said deformed condition; and, when the pipe liner is inserted into the pipe, locating the pipe liner in an undeformed condition in which the pipe liner has an increased transverse dimension; the method being characterized by the step of inserting the pipe liner into the pipe comprising the further steps of inserting the pipe liner into a carrier member whilst the pipe liner is in said deformed condition; applying a force to the carrier member so as to position said member within the pipe; À À À Àe.

À À À À Àe À À À À À À À À e Àe - À À . À À À À À .. À - 3 and withdrawing the carrier member from the pipe so as to leave the pipe liner inserted within the pipe.

Thus, in accordance with the present invention, it is possible to use a pipe liner of a relatively thin material which can be readily folded. Although such a liner will be too thin to be pushed into the pipe without crumpling, the carrier member can be made so as to be capable of transmitting compression forces whilst being able to bend around corners within the pipe and, accordingly, the pipe liner may be pulled through the carrier member or inserted laterally therein and the carrier member then pushed into the pipe. In this way, forces are applied to the carrier member rather than the pipe liner when inserting the liner into the pipe to be repaired. An undesirable crumpling of the relatively thin liner material is thereby avoided. Once the pipe liner has been located within the pipe (so as to extend across the suspected region of disrepair), the carrier member is withdrawn. The pipe liner may then expand so as to resume a circular cross-section. In so doing, the external surface of the pipe liner contacts the interior surface of the pipe. Ideally, the exterior diameter of the pipe liner is slightly larger than the interior diameter of the pipe so that, once expanded, the pipe liner mates with an interference fit with the pipe. The pipe liner and pipe are thereby fixedly secured to one another.

It will be appreciated that, because the pipe liner is of a relatively thin material, the internal diameter of the pipe liner is only slightly less than the internal diameter of the original pipe. This is important given the relatively small internal diameter of the original pipe. The performance of the supply pipe is not therefore significantly compromised.

However, it will also be appreciated that, because of the relatively thin material from which the pipe liner is made, the pipe liner is not intended to be structurally independent of the original pipe. The original pipe should therefore be considered as repaired rather than renewed. If the original pipe subsequently degrades and crumbles, then the pipe liner will tend to collapse and the pipe and pipe liner combination will need to be replaced.

In the method of the present invention, the pipe liner is preferably inserted into discrete portions of the carrier member. Adjacent portions of the carrier member are ideally positioned so as to abut with one another. Also, it is desirable for the pipe liner to À . . ..e c À . . . ... . . À À À À À À À À . À À À À be inserted laterally into the carrier member through a slot in the side of the carrier member and extending along the length of the carrier member.

Preferably, an elongate fixing member is positioned so as to extend from said pipe access to a location within the carrier member, the end of the fixing member distal to said pipe access releasably gripping the pipe liner so as to retain the pipe liner in position relative to the pipe when the carrier member is withdrawn. Following the step of withdrawing the carrier member, the fixing member is preferably withdrawn from the pipe. The step of withdrawing the fixing member may comprise the step of pulling the fixing member through the interior of the pipe liner and, in so doing, moving the pipe liner from a deformed condition to an undeformed condition.

The pipe is ideally a service pipe and more preferably a water service pipe.

A second aspect of the present invention provides apparatus for repairing a pipe, the apparatus comprising a pipe liner for lining a pipe to be repaired; and a carrier member for inserting into the pipe to be repaired, the pipe liner being held within the carrier member in a deformed condition in which the pipe liner is resiliently deformed along its length so as to have a reduced transverse dimension.

Thus, in accordance with the present invention, a pipe liner may be provided which is of a sufficiently thin material to allow ready deformation and expansion into an undeformed condition wherein the interior diameter of the repaired pipe is not significantly reduced. The use of such a pipe liner is facilitated by means of the carrier member which may be made to withstand the compression forces exerted when pushing the pipe liner into the pipe to be repaired.

The apparatus according to the second aspect of the present invention may further comprise a fixing member positioned within the pipe liner, a fixing member being radially expandable. A fixing member may extend the length of the pipe liner and, at one end, comprise a portion which is readily expandable. The said one end of the fixing member may be radially expanded by manipulation of the end of the fixing member distal to said one end. Furthermore, it is preferable for the carrier member to be of a cylindrical shape. The carrier member may also comprise a slot extending along one side and through which access to the interior of the member may be gained.

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À À À À . À . ... .. . An embodiment of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional side view of a domestic water supply pipe in need of repair; Figure 2 is a cross-sectional side view of the pipe shown in Figure 1 being repaired in accordance with the present invention; Figure 3 is a schematic perspective view of apparatus according to the present invention being inserted into a pipe in need of repair; and Figure 4 is a cross-sectional side view of the pipe of Figure I repaired in accordance with the present invention.

A domestic water supply pipe 2 is shown in Figure 1 of the accompanying drawings. The supply pipe 2 extends from a mains stop-cock 4 to supply a property with water. The supply pipe 2 can be seen to have a small hole 6 therein which gives rise to undesirable leakage of supplied water.

With reference to Figure 2, it will be seen that the supply pipe 2 may be repaired by sealing the hole 6 (and any other unknown holes or cracks in the pipe 2) in accordance with the present invention by inserting a folded pipe liner 8 In order to insert the liner 8, access must first be gained to the supply pipe 2. This may be conveniently achieved by removing the property stop-cock or other fixture 10 at the end of the supply pipe 2 distal to the mains stop-cock 4. No excavation of the ground in which the supply pipe 2 may be buried need therefore be made. Once access to the interior of the supply pipe 2 has been gained, the pipe liner 8 may be run into the supply pipe 2 in a folded state and, once in position, expanded so as to sealingly contact the interior surface of the supply pipe 2.

The supply pipe 2 will typically have an internal diameter of approximately 25mm and, as such, the pipe liner 8 is manufactured from a relatively thin material so as to allow the liner 8 to be readily folded along its length (for insertion into the pipe 2) and so as to ensure that the internal dimensions of the pipe 2 when lined are not proportionally reduced to such an extent that supply performance is adversely affected. The pipe liner 8 may be manufactured from a suitable material, for example, natural or synthetic rubbers.

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À À À À À À À À À À À À À As a consequence of the relatively thin material from which the pipe liner 8 is manufactured, the pipe liner 8 is inserted into the supply pipe 2 by means of a carrier member 12. The carrier member 12 is manufactured from a relatively stiff material so the carrier member 12 may be readily pushed from one end thereof into the supply pipe 2.

Nevertheless, the material of the carrier member 12 is sufficiently flexible to allow the carrier member 12 to flex about those bends typically found in water pipes.

Prior to inserting the carrier member 12 into the supply pipe 2, the pipe liner 8 is located within the carrier member 12. [his may be achieved in a number of ways depending on the form of the carrier member 12. The carrier member 12 may be of a cylindrical shape (eg a pipe). The pipe liner 8 may be located within such a carrier member 12 by inserting one end of the pipe liner 8 (which should already be folded about its longitudinal access as shown in Figure 3) and pulled through the length of the carrier member 12. Given the flexible nature of the pipe liner 8, it will generally not be possible to push the pipe liner 8 through the carrier member 12. The liner 8 may be pulled through the carrier member 12 by, for example, attaching a cord to that end of the liner 8 to be first inserted into the carrier member 12 and dropping the cord through the carrier member 12 so that it may be grasped by a user at the end of the carrier member 12 distal to the end at which the pipe liner 8 is inserted. By pulling the cord, the pipe liner may be conveniently pulled through the full length of the carrier member 12.

Alternatively, the carrier member 12 may take the form of a cylinder having an elongate slot extending longitudinally along the full length of said member. With reference to Figure 3, a suitable slot 14 is shown in phantom. In use, an unfolded pipe liner 8 may be placed along the length of the slot 14 and pushed through the slot 14 laterally into the interior of the carrier member 12. In pushing the pipe liner 8 through the slot 14, the pipe liner 8 will tend to assume a folded configuration. A suitable tool (for example, a small gauge rigid wire) may be placed along the length of the slot 14 and over the pipe liner 8 so as to assist in pressing the pipe liner 8 through the slot 14.

Furthermore, the carrier member 12 may be provided in separate sections 16 which can be screw threaded to one another as the pipe liner 8 is being inserted into the supply pipe 2 (see Figure 2). In this way, long lengths of pipe liner 8 may be inserted into À À À Àee À À À À À À Àe a e À À À À À À À À À À À À À À À À a supply pipe 2 in a relatively convenient fashion. In this regard, the pipe liner 8 may, for example, be supplied on a roll, pressed into a carrier section 16, pushed into the supply pipe 2, and then cut to length once finally positioned within the pipe 2. Ideally, the pipe liner 8 is pushed into the supply pipe 2 until it abuts the mains stop-cock 4. The pipe liner 8 is then pulled back from the stop- cock by a short distance (for example, four inches) in order to provide a degree of clearance. Eke carrier member 12 is then withdrawn from the supply pipe 2 so as to leave the pipe liner 8 in position.

In order to ensure that the pipe liner 8 does not withdraw from the supply pipe 2 together with the carrier member 12, it is desirable to hold the pipe liner 8 relative to the supply pipe 2 with some appropriate means. This may simply involve holding the end of the pipe liner 8 projecting from the exposed end of the supply pipe 2. As the carrier member 12 is withdrawn, the end of the pipe liner 8 adjacent the mains stop-cock 4 will tend to expand into contact with the supply pipe 2 and, as a result of friction forces, will tend to grip the supply pipe 2 and thereby assist in keeping the pipe liner 8 in the desired position relative to the supply pipe 2. Nevertheless, a suitable fixing member may be advantageously employed to secure a portion of the pipe liner 8 to the supply pipe 2 (at least while the carrier member 12 is being withdrawn). A long slim tool having one end which may selectively expanded in a radial direction may be inserted into the interior of the pipe liner 8. The expandable head is located adjacent the end of the pipe liner 8 to be positioned adjacent to the mains stop-cock 4. Once the pipe liner 8 is finally positioned within the supply pipe 2, the tool head may be readily expanded so as to grip the pipe liner 8 and subsequently force said liner 8 into contact with the supply pipe 2. Such a tool may be used in conjunction with a cylindrical carrier member 12 of the types shown in the accompanying drawings or may be used alone as a carrier member for the pipe liner 8.

In this latter case, the head of the tool must be capable of gripping the pipe liner 8 and the tool must be sufficiently stiff to allow the tool to be pushed into the supply pipe 2 whilst effectively dragging the pipe liner 8 into position within the supply pipe 2.

It will also be understood that a fixture 18 may be left within the supply pipe 2 so as to secure the pipe liner 8 in position (see Figure 4). The fixture 18 may be in the form À . À ...

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À À e À À À . . À - - 8 of a spring clip and will be of particular assistance in ensuring that the pipe liner 8 remains in position whilst the carrier member is being withdrawn. It will also be understood that, when the aforementioned expandable head tool is used in conjunction with a carrier member 12 having an elongate slot 14, the expandable head tool located within the full length of the pipe liner 8 may be used to assist in pressing the liner 8 through the slot 14.

Once the pipe liner 8 is in position within the supply pipe 2, the carrier member 12 is withdrawn and the liner 8 unfolded into an expanded condition in which the liner 8 assumes a circular cross-section. Where a tool extending through the interior of the liner 8 is used, withdrawal of said tool will have a tendency to assist in expanding the liner 8 into its circular cross-section. Pressurising the interior of the pipe liner 8 with water will also ensure that the liner 8 expands correctly. When in the expanded condition, the pipe liner 8 contacts the interior surface of the supply pipe 2 and seals any holes or cracks therein. The pipe liner 8 will even bridge small gaps between spaced sections of supply pipe 2 (for example, in a pipe connection fixture). With the pipe liner 8 located, surplus liner 8 extending from the supply pipe 2 may be removed and the fixture lo reassembled as shown in Figure 4.

The present invention is not limited to the specific embodiments and materials described above. Alternative arrangements will be apparent to a reader skilled in the art.

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Claims

CLAIMS: 1. A method of repairing a pipe, the method comprising the steps

of exposing an access to the interior of the pipe; locating a pipe liner in a deformed condition in which the pipe liner is resiliently deformed along its length so as to have a reduced transverse dimension; inserting the pipe liner into the pipe via said access whilst the pipe liner is in said deformed condition; and, when the pipe liner is inserted into the pipe, locating the pipe liner in an undeformed condition in which the pipe finer has an increased transverse dimension; the method being characterized by the step of inserting the pipe liner into the pipe comprising the further steps of inserting the pipe liner into a carrier member whilst the pipe liner is in said deformed condition; applying a force to the carrier member so as to position said member within the pipe; and withdrawing the carrier member from the pipe so as to leave the pipe liner inserted within the pipe.
2. A method as claimed in Claim 1, wherein the pipe liner is inserted into discrete portions of the carrier member.
3. A method as claimed in Claim 2, wherein adjacent portions of the carrier member are positioned so as to abut with one another.
4. A method as claimed in any of the preceding claims, wherein the pipe liner is inserted laterally into the carrier member through a slot in the side of the carrier member and extending along the length of the carrier member.
5. A method as claimed in any of the preceding claims, wherein an elongate fixing member is positioned so as to extend from said pipe access to a location within the carrier member, the end of the fixing member distal to said pipe access releasably gripping the pipe liner so as to retain the pipe liner in position relative to the pipe when the carrier member is withdrawn.

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À À À À À À À À À . . . - À . .
6. A method as claimed in Claim 5, wherein, following the step of withdrawing the carrier member, the fixing member is withdrawn from the pipe.
7. A method as claimed in Claim 6, wherein the step of withdrawing the fixing member comprises the step of pulling the fixing member through the interior of the pipe liner and, in so doing, moving the pipe liner from a deformed condition to an undeformed condition.
8. A method as claimed in any of the preceding claims, wherein said pipe is a service pipe.
9. A method as claimed in Claim 8, wherein said pipe is a water service pipe.
10. Apparatus for repairing a pipe, the apparatus comprising a pipe liner for lining a pipe to be repaired; and a carrier member for inserting into the pipe to be repaired, the pipe liner being held within the carrier member in a deformed condition in which the pipe liner is resiliently deformed along its length so as to have a reduced transverse dimension.
11. Apparatus as claimed in Claim 1 O. the apparatus further comprising a fixing member positioned within the pipe liner, the fixing member being radially expandable.
12. Apparatus as claimed in Claim 11, wherein the fixing member extends the length of the pipe liner and, at one end, comprises a portion which is radially expandable.
13. Apparatus as claimed in Claim 12, wherein said one end ofthe fixing member is radially expanded by manipulation of the end of the fixing member distal to said one end.

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l 4. Apparatus as claimed in any of Claims 10 to 13, wherein the carrier member is of a cylindrical shape.
15. Apparatus as claimed in any of the preceding claims, wherein the carrier member comprises a slot extending along one side and through which access to the interior of the member may be gained.
16. A method substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
17. Apparatus substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

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