GB2330187A

GB2330187A - A pipeliner

Info

Publication number: GB2330187A
Application number: GB9721196A
Authority: GB
Inventors: Samuel Gardiner
Original assignee: Texon UK Ltd
Current assignee: Noxet UK Ltd
Priority date: 1997-10-08
Filing date: 1997-10-08
Publication date: 1999-04-14
Also published as: GB9721196D0

Abstract

A pipeliner (2) for renovation of a pipe comprises a fabric tube which may be laminated with a barrier layer. The tube has a folded-over section (1) at one end, which may include an insert (3). In use the tube is impregnated with a curable resin which is cured to a rigid condition with the tube in engagement with a pipe to be renovated. The folded-over section (1) provides an area of preferentially abutting pipeliner in engagement with the pipe (21) to give an improved seal; the insert (3) may further enhance the seal. The insert (3) may comprise a ring of rubber material or a sealing compound or gel, and the pipeliner may be constructed from felt. The folded-over sections may also form shoulder portions to allow adjacent pipeliners to abut one another.

Description

PIPELINER FOR RENOVATION The present invention relates to pipeliner for renovation and more particularly, but not exclusively, to a pipeliner used with regard to sewerage pipes.

It will be appreciated that pipes such as sewerage system networks must be regularly inspected and maintained in order to ensure an efficient operation. Furthermore, a collapsed pipe in an inaccessible location or underground will be difficult to repair. Thus, it is important that such pipes are repaired prior to collapse.

One obvious way of regenerating a worn pipe is to reinforce it. One such approach to reinforcing pipes involves locating a fabric tube with laminated barrier layer within the pipe to be renovated and with the fabric tube impregnated with a curable resin. Thus, upon curing of the resin whilst inflated, a rigid reinforcing sleeve or pipe liner is located substantially concentrically within the pipe to be renovated. Such fabric tube/curable resin renovation systems are both cheap and effective.

Typically, lengths of fabric tube impregnated with the curable resin are installed within the pipe to be renovated between access points, e.g. manholes. A normal length will therefore be 50 or 100 metres of pipeliner depending upon the diameter of the pipe to be renovated. It is necessary to renovate substantial lengths of pipe in each operation in order to achieve economic performance but also to reduce the problems associated with seepage between the pipeliner once cured and the wall of the pipe to be renovated. Each end of the pipeliner once cured poses a potential access point for seepage into the gap between the pipe to be renovated and the pipeliner.

As indicated above, a principal application of the present invention is with regard to sewerage pipe systems.

In such sewerage pipe systems seepage behind the cured pipeliner can allow persistent erosion of the pipe and so potential fouling of the soil and eventually ground water about the sewerage pipe. Furthermore, it is possible in temperate climates or cooler for the seepage to freeze, further enhancing erosion and potentially cracking of the cured pipeliner.

In view of the above it will be appreciated that attempts have been made to reduce the potential for such back seepage within sewerage systems in particular. The typical approach taken is to introduce sealing compounds such as mastics to seal the edge section of the cured pipeliner or simply grout such end of the cured pipeliner.

Alternatively, rubber seal elements or possibly stuffing boxes have been used in more elaborate applications then generally utilised in sewerage systems. However, such approaches can significantly increase installation cost for renovation of a pipe as it requires several man hours potentially to grout or seal these end sections of the pipeliner. It is also possible to create end flanges of slit petalled pipeliner to ensure good cured pipeliner location within the pipe to be renovated. Such location can also facilitate and alleviate a further problem with regard to pipe renovation in that the pipeliner once cured within the pipe to be renovated can be subject to relative longitudinal and lateral movement due to thermal cycling and seismic activity about the pipeliner. Such movement can, again, facilitate seepage behind the pipeliner.

It is an objective of the present invention to provide a pipeliner in which the above problems with regard to seepage are substantially eliminated.

In accordance with the present invention there is provided a pipeliner for renovation of a pipe, the pipeliner including a fabric tube suitable for impregnation with a curable resin, the pipeliner, in use, being arranged to have a turned-over section at one or both ends in order to achieve an area of preferentially abutting pipeliner in engagement with a pipe to be renovated in use.

The turned-over section may be arranged such that the fabric, i.e. felt, of the pipeliner is in engagement with the pipe to be renovated or such that a barrier layer of the pipeliner is in contact with the pipe to be renovated.

The turned-over section may be stuck along mutual flats in order to enhance the robustness of such turned-over section.

The turned-over section may incorporate an insert to further enhance the sealing abutment about the end of the pipeliner.

The folded-over section of the pipeliner may be achieved manually prior to installation, or after installation by an operative through an access point with the pipeliner located within the pipe to be renovated.

Alternatively, the folded-over section may be achieved using a purse string technique or using a thermo-shrinking effect upon the pipeliner end to stimulate fold-over by application of heat or other activation means selectively about the end portion of the pipeliner. Such thermo-shrinking could be achieved with regard to the barrier film laminated typically to the pipeliner.

The present invention also includes a pipe renovated in accordance with and incorporating a pipeliner with foldedover sections as described above The embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is an example of a pipeliner including a folded-over section; and Figure 2 is a pipeliner incorporating a folded-over section, as depicted in Figure 1, incorporated within a pipe to be renovated.

In accordance with the present invention the objective, as depicted above, is to reduce seepage behind the pipeliner in use. In order to achieve this objective an end configuration for the pipeliner is achieved such that a preferential abutment seal is achieved.

In Figure 1 a schematic cross-section of a pipeliner end in accordance with the present invention is depicted.

At the core of the invention is provision of a folded-over section (1) at the end of a pipeliner (2). In the embodiment illustrated in Figure 1 the folded-over section incorporates an insert (3). However, such an insert (3) is not essential to the invention. It will be appreciated that the pipeliner (2) comprises a felt fabric with laminated barrier layer. The felt fabric is impregnated with a curable resin such that upon installation the curable resin cures to a rigid state whilst the pipeliner (2) is held in an expanded inflated configuration either by a calibration tube or similar technique. Thus, there is a significant radial force projecting the folded section (1) outward from the longitudinal axis of the pipeliner (2). The curable resin held within the fabric of the pipeliner (2) is also impregnated into the fabric of the pipeliner in the vicinity of the folded section (1). Thus, irrespective of whether the curable resin is of a so-called cold cure or of a type that requires an elevated temperature in order to activate it, the radial force presented by the calibration bladder inserted into the pipeliner during installation will typically stimulate differential curing of the resin. It will be appreciated that if the calibration tube or bladder located within the pipeliner (2) includes hot water or similar fluid in order to activate the curable resin then, typically, the inner surface of the folded section (1) will generally rigidise, i.e. cure, before an outer section (5) thus, the bias or radial force applied by the calibration bladder is incorporated into the pipeliner end (1) by such differential curing. Similarly, with a so-called cold cure resin where an activator compound is mixed with the resin prior to impregnation, although the differential curing rates described with regard to relatively hot cure resin are not as pronounced, the bias retention of the end (1) is still achieved due to the rigidisation of the inner surface (4) of the folded section (1). It will be appreciated that the radial force applied by the calibration bladder inserted into the pipeliner (2) during installation ensures that the inner surface (4) of the section (1) assumes a compressive radial expansion onto the outer surface (5). Thus, some of this radial compressive force is retained due to the rigidisation of the pipeliner whilst still under the inflationary effect of the calibration tube located within the pipeliner.

With the retention of some of the radial compression effect of the calibration tube a better seal is created by the end folded section (1) of the pipeliner (2). Thus, the likelihood of seepage beyond the end (1) of the pipeliner in use is substantially diminished.

As indicated above, the insert (3) is not essential to the present invention but can further enhance the radial expansive compression in order to achieve an even greater sealing effect. The insert (3) can comprise a simple ring of rubber material or comprise a sealing compound or gel in order to create an improved sealing bond. It will be appreciated by those skilled in the art that a wide range of insert formats could be used including as indicated above, a rubber ring, a rupturable envelope of sealing compound arranged to disperse under compression from the calibration tube upon installation of a sealing compound, a ring of material having a positive coefficient of expansion upon cooling for the temperature ranges used with regard to resin curing such that further radial compression is achieved, or any other radial compression enhancement configuration. It will also be understood that the insert (3) could be shaped to achieve the most appropriate radial seal strength for the end (1).

In order to create the folded-over section (1) a multitude of techniques can be employed depending upon the prevailing circumstances. Thus, and for example only, the following techniques could be used a. A section of the pipeliner could simply be projected beyond a junction point and an operator designated simply to fold a section of the pipeline to back upon itself to create the folded-over section (1). In such a scenario, an insert (3) would simply be rolled onto the end of the pipeliner (2) for incorporation as depicted in Figure 1. Furthermore, the flats between surfaces (4, 5) could be adhered together in order to further enhance the robustness of the folded-over section (1). b. As indicated above, the pipeliner (2) will generally comprise a fabric laminated with an appropriate barrier film. Thus, this barrier film could either be inherently or be treated in order to achieve a shrinkage effect by appropriate conditioning in order to achieve the folded-over section (1). An example of such a technique would be to roll an insert (3) over the end of the pipeliner (2) and secure it in position, then swell the section of the pipeliner (2) beyond the secured insert (3) such that it expands, then apply heat or some other activation technique along with possibly some shaping step in order to present the expanded section back over the insert (3) and to shrink in order to constitute the folded-over section (1). c. Again, an end section of the pipeliner (2) could be swollen in some way and the periphery end of the pipeliner (2) incorporate a purse string which can be used to guide the surface (5) brought back onto the pipeliner (2) and drawn along with possible heat shrinking in order to create the folded-over section (1).

It will be appreciated that other techniques could be used in order to create the folded-over section (1).

It will be understood that to achieve an adequate seal in order to inhibit and hopefully prevent seepage, the folded-over section (1) should have an adequate sealing width. Thus, it is normal for the folded-over section to have a length of at least 10 centimetres and preferably 30 centimetres in order to achieve a reasonable sealing performance. However, the length of the folded section (1) could be significantly greater with the large diameter pipeliner applications. Furthermore, the use of an insert (3) may diminish the necessary length of the folded-over section (1) to achieve a desired sealing performance. For example, inclusion of two space inserts (3) will create two bands of sealing compression and so potentially greatly increase sealing performance as a composite of two radial seals which individually may not be as great as a single insert seal but as a combination have better performance.

Figure 2 illustrates a folded-over section (1) in a pipeliner (2) incorporated within a sewerage pipe (21). The calibration bladder (shown in broken line) comprises a fluid under pressure, typically from a header tank. Thus, a radial force is applied in the direction of the arrowheads.

This radial force is applied whilst the curable resin held within the fabric of the pipeliner (2) is curing. Thus, some of the compressive force attributable to the calibration bladder is retained by the pipeliner and so a compressive force is consistently applied once the calibration bladder is removed. In such circumstances the ends of the pipeliner (2) are sealed against the sewerage pipe (21) and so the possibility of seepage into the gap between the pipeliner (2) and the sewerage pipe (1) is greatly diminished.

Alternatively, and as depicted on the other side of the junction, the pipeliner may be allowed to extend slightly beyond the junction of the sewerage pipe (1) such that the portion of the folded-over section (la) is allowed to wrap around the edge of the sewerage pipe (21) and so enhance the sealing effect at this point. Such a configuration would also inhibit longitudinal movement of the pipeliner (2) within the sewerage pipe (21) and so possibly reduce any detrimental effects due to abrasion as a result of such movement.

In accordance with the present invention, it is possible for the barrier film of the pipeliner (2) to be presented either in contact with the sewerage pipe (21) or such that the fabric of the pipeliner (2) is in contact with the sewerage pipe (21). However, irrespective of the orientation of the pipeliner (2) it is possible to incorporate within the surface (5) of the folded-over section (1) an appropriate compound in order to secure such surface (5) to the sewerage pipe (21) thus, adhesives could be used to achieve such an effect.

As described above, it is an objective of the present invention to avoid the necessity of grouting by inclusion ol some sort of sealing compound at the ends of the pipeline (2) to inhibit or prevent seepage. However, in order tc further enhance the seal at the end of the pipeliner (2) it will be understood that a grouting compound or sealant coulc be applied to supplement the seal achieved by the foldedover section (1). The amount of grouting compound OI sealant necessary along with the skill necessary in its application will be significantly diminished and ths integrity of the seal at the end of the pipeliner (2) will be less dependent upon such grouting in accordance with thf present invention.

It will be understood by those skilled in the art that the folded-over section (1) even excluding any insert (3) still slightly diminishes the cross-section of the pipeline (2) at its end in comparison with the bulk of its length.

However, in some applications it is possible to use thf slight constriction in the diameter of the pipeliner (2) at its end by overlapping such ends in order that two lengths of pipeliner (2) can be keyed together by the should elements created by the folded-over sections (1) oA respective lengths of pipeliner (2) interlocking.

Claims

CLAIMS 1. A pipeliner for renovation of a pipe, the pipeliner including a fabric tube suitable for impregnation with a curable resin and having a turnedover section at one or both ends in order to provide, in use, an area of preferentially abutting pipeliner in engagement with a pipe to be renovated in use.
2. A pipeliner according to claim 1 wherein the fabric tube comprises felt and a barrier layer laminated thereto wherein the turned-over section is such that the felt is in engagement with the pipe to be renovated.
3. A pipeliner according to claim 1 wherein the fabric tube comprises felt and a barrier layer laminated thereto wherein the turn-over section is such that the barrier layer is in contact with the pipe to be renovated.
4. A pipeliner according to any one of the preceding claims wherein the turned-over section is stuck along contact flats between inner and outer surfaces to enhance the robustness of the turned-over section.
5. A pipeliner according to any one of the preceding claims comprising an insert in the turned-over section to enhance the sealing abutment about the end of the pipeliner.
6. A pipeliner according to claim 5 wherein the insert is a sealing ring.
7. A pipeliner according to claim 5 wherein the insert is a sealing compound or gel.
8. A pipeliner according to claim 5 comprising two spaced inserts.
9. A pipeliner constructed arranged and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.
10. A renovated pipeline comprising a pipeliner according to any one of the preceding claims installed in a pipe.
11. A pipeline according to claim 10 wherein the pipeliner comprises a felt fabric impregnated with a resin cured to a rigid state.
12. A pipeline according to either one of claims 10 and 11 wherein the pipeliner extends slightly beyond an edge portion of the pipe such that a portion of the turned-over section is wrapped around the edge.
13. A pipeline according to any one of claims 10 to 12 wherein an outer surface of the turned-over section is secured the pipe by an appropriate compound.
14. A pipeline according to any one of claims 10 to 13 comprising two lengths of pipeliner according to any one of claims 1 to 9 keyed together by interlocking of shoulder elements created by the turned-over sections.
15. A method of renovating a pipeline using a pipeliner including a fabric tube impregnated with a curable resin comprising introducing the tube into a pipe to be renovated and folding over a leading end portion of the tube to provide a turned-over section at the leading end portion of the tube in engagement with the pipe to be renovated.
16. A method of renovating a pipeline using a pipeliner including a fabric tube impregnated with a curable resin comprising introducing the tube into a pipe to be renovated wherein a leading end portion of the tube consists of a turned-over section in engagement with the pipe to be renovated.
17. A method according to either one of claims 15 and 16 in which is used a pipeliner according to any one of claims 1 to 9.