GB2302152A - Pipeline renovation - Google Patents

Abstract

A thin walled tubular membrane 11 around the periphery thereof is secured at a region to the inside or outside wall of the pipe. The membrane is secured so that it is held open at the region of securement for liquid or gas to flow therethrough. As the liquid or gas flows through the open end of the membrane, the tube is drawn along the length of pipe and is held against the wall of the pipe by the flow of the liquid or gas. Initially, the pipe is stopped at a section, a bypass provided to continue fluid flow and a new section 10 put in, this containing the membrane 11, optionally gathered in a side container 14.

Description

PIPELINE RENOVATION This invention relates to a method and apparatus for pipeline renovation, and more particularly to the internal renovation of liquid- or gas-carrying pipelines.

It is well known that, over a period of time, liquid- or gas-carrying pipelines can suffer internal corrosion and/or breakdown which can result, for example, in leaks and in contamination of the fluid passing therethrough. Since complete replacement of a pipeline can be extremely expensive, attempts have been made to renovate older pipelines by providing an internal lining therein to cover the internal wall and keep the fluid out of contact therewith. In the water industry, linings have been provided in a number of ways, including introducing a new pipe or a liner member into an existing pipeline, spraying a coating onto the inside of the pipeline, and using cured-inplace liners. All these techniques have had some success but none is wholly satisfactory.In particular, they all require pre-cleaning of the inside of the pipeline and shutdown of the fluid supply, and this involves significant disruption and cost.

We have now devised a way of internally renovating a liquid- or gas-carrying pipeline whereby these prior known difficulties can be reduced or overcome.

According to a feature of the present invention, we use a thin tubular membrane to line the inside of the pipeline. Since the thin membrane is flexible, it can be installed without closing down the pipeline, for example by using line stopping techniques and the membrane can if necessary be disinfected off-site prior to installation.

The present invention is broadly applicable to the renovation of all liquid- or gas-carrying pipelines, but it is especially useful in the water industry for mains water pipelines and it will hereafter be described in relation thereto. It is to be understood, however. that it can be applied mutatis mutandis to the renovation of other liquidcarrying pipelines where the liquid is aqueous or nonaqueous, and also to the renovation of gas-carrying pipelines where the gas is at a relatively low pressure.

According to a preferred aspect of the invention, the thin tubular membrane is secured around its periphery to the inside or outside wall of the pipeline so that the tube is held open at the region of securement for the liquid to flow there through. The liquid flow through the membrane can serve to maintain it in elongate extended condition in the pipeline and to hold it against the inside wall of the pipeline. In this arrangement, the membrane can be secured to the pipeline at or close to the upstream end of the tubular membrane, so that as the water flows through the length of the membrane, it is expanded radially outwardly to bear on and cover the internal wall of the pipeline.

Preferably, the membrane is sealed in substantially water-tight fashion to the internal or external wall of the pipeline at the securement region.

This can be effected in a number of ways, such as by providing an internal or external flange on the pipeline and/or by using a spring-loaded annular member within the membrane to hold it against the pipeline, or by clamping the membrane to the outside of the pipe in a secure fashion and feeding it into the pipe, eg. at a make up piece joint.

Alternatively, if the new section is plastic. the membrane may be attached by means of a weld.

Whilst in one preferred arrangement. the tubular membrane is secured to the pipeline wall at one securement region only. it can also be secured at one or more other regions if desired.

The membrane used in the present invention will normally be of tubular plastics film. In the expanded condition, with water flowing therethrough, its crosssectional dimensions will be at least equal to those of the pipeline so that the membrane can lie against the pipeline inner wall over substantially its whole periphery. Suitable plastics materials include polyethylene, polypropylene, polybutylene and polyethylene terephthalate up to 500um.

Whilst the invention is applicable to pipe lining generally. it is especially useful for ferrous and cementitious water mains of diameter from 75cm to 1000cm.

As will be clear to those skilled in the art, the thin tubular membrane can be introduced into the pipeline, and located therein, in a number of ways. For water mains, we prefer to provide a temporary water by-pass in a section of a main and then to replace the old section with new section incorporating the membrane. Then, when the new section is brought on line, water flow through the tubular membrane extends it downstream and expands it to lie against the inner wall of the pipeline. The membrane is secured to the wall of the new section of pipeline. The invention thus includes a pipeline section including a flexible tubular membrane peripherally secured to the inner wall of the section at one region thereof whereby fluid flowing in the section will pass through the tubular membrane and extend it against the pipeline wall.

In order that the invention may be more fully understood, various embodiments thereof will now be described, by way of example only, with reference to the accompanying schematic drawings. wherein: FIGURE 1 shows the pipe to be renovated; FIGURE 2 shows the pipe with the line stop and bypass in place; FIGURE 3 shows the thin membrane pipelining (TMP) unit; FIGURE 4 shows the TMP unit installed between the line stops; FIGURE 5 shows the membrane installation process; and FIGURE 6 shows the installed lining.

In the following description of the drawings, like numerals indicate like parts. Referring to the drawings, Figure 1 shows the pipeline 1 which is to be renovated, thus being a water main in which the water flow direction is indicated by arrow 2.

The flow of water in line 1 is stopped by the insertion of two line stops 3,4 spaced apart a short distance eg. 5 metres (see Figure 2). A by-pass 5 is installed with control valves 6,7 at each end. Thus. flow of water is maintained via the by-pass, and the length 8 of pipe 1 between the stops 3 and 4 is drained of water. The region 20 of pipeline 1 which is to be renovated is downstream of length 8 (see Figure 6). The arrangement shown in Figure 2 is a common procedure in the art and can be achieved with minimal disruption to the water supply, as will be understood by those skilled in the art.

The next stage is to remove part of length 8 of pipe 1 and replace it with a new section 10 (Figure 3).

This new section 10 has one end 11 of a thin flexible tubular membrane 12 fixed to the inner wall thereof by a fixing means 13. The end 11 of membrane 12 is thus held open and is facing downstream. The remainder of the membrane liner 12 can either be folded in the section 10 or (as illustrated) be stored in a sealed container 14 on the side of section 10. the liner passing through a small tube 15 into the section 10.

The free end 16 of the tubular membrane 12 is temporarily sealed, eg. with a rubber band or the like. The membrane 12 and modified pipe section 10 (and container 14) have all been disinfected off-site.

The pipe section 10 (with membrane 12 and container 14) is now installed in pipeline 1 between the two stops 3.4 (see Figure 4). The by-pass is closed and the stops 3,4 removed (Figure 5). As the water begins to flow through section 10 in the direction of arrow 2. it enters.

the fixed end 11 of membrane 12 and draws the membrane out of container 14. The water filling the membrane expands it radially and holds it against the inner wall of the pipeline 1 to serve as a liner. When the whole of the membrane has been inverted, the temporary seal at free end 16 is released and the final configuration shown in Figure 6 is achieved.

Claims (20)

CLAIMS:

1. A method of renovating a pipe, comprising securing a thin tubular membrane around the periphery thereof to an inside or outside wall of the pipe so that the tubular membrane is held open at the region of securement for liquid or gas to flow therethrough, and passing the liquid or gas through the open end of the membrane, whereby the tube is drawn along the length of the pipe, and is held against the wall of the pipe by the flow of the liquid or gas.

2. A method according to claim 1, wherein the membrane is secured to the pipe wall at a plurality of securement regions.

3. A method according to claim 1 or 2, wherein the membrane comprises a tubular plastics film.

4. A method according to claim 1 or 2, wherein the tubular membrane is polyethylene, polypropylene, polybutylene or polyethylene terephthalate.

5. A method according to claim 3 or 4, wherein the membrane has a thickness less than or equal to 500 micrometers.

6. A method according to any preceding claim, wherein the cross sectional dimension of the tubular membrane, when in an expanded condition, is at least equal to the cross sectional dimension of the pipe, so that the membrane can lie against the pipe wall over substantially its whole periphery.

7. A method according to any preceding claim, wherein the membrane is secured to the pipe by providing an internal or external flange on the pipe.

8. A method according to any one of claims 1 to 6, wherein the membrane is secured to the pipe by using a spring-loaded annular member within the membrane to hold it against the pipe.

9. A method according to any one of claims 1 to 6, wherein the membrane is secured to the pipe by clamping the membrane to the outside of the pipe in a secure fashion, then feeding the membrane to the interior of the pipe.

10. A method according to any one of claims 1 to 6, wherein the membrane is secured to the pipe by welding it to the pipe.

11. A method according to any preceding claim, wherein the membrane has a free end remote from the end secured to the pipe, and said free end is initially temporarily sealed.

12. A method according to any preceding claim, wherein the pipe is a water main, and said method further includes the steps of providing a temporary water bypass in a section of the main, replacing at least part of the bypassed section with a new section incorporating the membrane, removing the temporary bypass so that water flows thorough the new section and through the membrane to extend it downstream and to expand it to lie against the inner wall of the main.

13. A method according to claim 12, wherein the membrane is folded in the new section prior to starting water flow therethrough.

14. A method according to claim 12, wherein the membrane is folded in a separate container prior to starting water flow therethrough, and the membrane passes through a small tube from the separate container into the new section.

15. A renovated pipeline section comprising a pipe and a flexible tubular membrane secured to the inner wall of the pipe at one region thereof, whereby fluid flowing through the section will pass through the tubular membrane and expand it against the pipeline wall.

16. A pipeline section according to claim 15, wherein the tubular membrane is a tubular plastics film.

17. A pipeline section according to claim 15, wherein the tubular membrane is polyethylene, polypropylene, polybutylene or polyethylene terephthalate.

18. A pipeline section according to claim 16 or 17, wherein the membrane has a thickness of less than or equal to 500 micrometers.

19. A method of lining a pipe substantially as herein described with reference to and as shown in the accompanying drawings.

20. A pipeline section substantially as herein described with reference to and as shown in Figures 3 to 6.