GB2226615A

GB2226615A - Conduit lining

Info

Publication number: GB2226615A
Application number: GB8928207A
Authority: GB
Inventors: Stephen Michael Vick; Richard Fraser
Original assignee: VICK STEVE Ltd; Drain Technology Ltd
Current assignee: VICK STEVE Ltd; Drain Technology Ltd
Priority date: 1988-12-28
Filing date: 1989-12-13
Publication date: 1990-07-04
Also published as: GB8830292D0; GB8928207D0

Abstract

For lining a hollow body, particularly a pipe, (10) or cable conduit, a former (16) bearing an elongate annular bag (18) is located therein. The bag (18) e.g. of nylon mesh is then expanded by passing in a settable composition e.g. epoxy, which may leak through outer portions (18b) to seal to the pipe (10). The former (16) may then be removed. It may be contractable to facilitate this. It may have a through passage (24) so that flow along the pipe (10) is not prevented during the lining process. <IMAGE>

Description

CONDUIT LINING The present invention relates to a method and apparatus for providing a lining within a hollow body, particularly a tubular conduit, e.g. for repairing or renovating a conduit such as a drainage, water or gas pipe or a communications conduit, e.g. for containing telephone cables.

In one aspect the invention provides a method of providing an annular liner within a hollow body (particularly a tubular conduit) comprising providing an annular bag; locating the bag within the body; passing a settable composition into the bag so that the bag is inflated thereby and urged to expand radially whereby it is urged into contact with the hollow body at a region where a liner is required; and allowing or causing the composition to set. The annular bag may be mounted on a former or core to facilitate its location and to provide a reaction surface so that the inflation of the bag provides greater forces in radially outward directions. The former may have a through passage, so that the assembly does not provide a complete barrier across the body. The former may be removable.In order to facilitate this, it may be radially retractable, e.g. comprising an inflatable/ deflatable sac.

The settable composition may be an expanding foam composition whose expansion urges inflation of the bag.

Alternatively or additionally, expansion may be urged by externally applied pressure.

The annular bag may have a radially outer wall portion through which the settable composition can penetrate so that it contacts the hollow body and adheres to it. Unless the former is intended to be a permanent part of the liner, the bag will generally contact the former with an impervious wall portion.

An embodiment of the invention will now be described in greater detail with reference to the accompanying drawings, in which: Fig. 1 is a schematic axial section through a pipe which is being lined by a method embodying the invention; and Fig. 2 is an end view of the assembly shown in Fig.

1.

The pipe 10 to be lined is assumed to have a portion 12 in need of lining, e.g. because it has been found to be damaged or because it is aged and is likely to become unreliable. A lining assembly 14 has been moved within the pipe 10 to the region 12. The assembly involves a former 16 of somewhat smaller diameter than the internal diameter of the pipe 10, and an annular bag 18 mounted on the former 16. The bag may be formed of fabric, e.g.

nylon mesh. The radially inner wall portion 18a (which is in contact with the former 16) is rendered impermeable, e.g. by impregnation with a resin material. The radially outer surface 18b has some porosity. An inlet pipe 20 communicates with the interior of the bag 18. Initially, the bag 18 is in a deflated state, so that it is easy to move the assembly 14 along the pipe 10 to the desired location 12. Once it is at the location 12, a settable composition 22 is passed along the inlet tube 20 and into the bag 18, which is thus inflated. Pressure applied externally and/or generated by expansion of the settable composition urges inflation of the bag 18. This is thus urged radially outwardly against the pipe 10, and a small proportion of the settable composition oozes through the radially outer wall of the bag 18 and comes into contact with the pipe 10.Thus when the composition sets, the bag and the composition become an annular liner bonded sealingly to the desired region 12 of the pipe 10.

The former 16 may have an axial through passage 24, so that flow communication along the pipe 10 is not cut off during installation of the liner. Once the liner has been formed, the former 16 may be withdrawn. This is facilitated if at least a radially outer part of it is deflatable or is otherwise reducible in radial extent.

The assembly 14 can be dimensioned to suit many different purposes. For example, it may be such that the liner produced is of small radial extent (e.g. 8mm) and of substantial length (e.g. lem).

The settable composition 22 may be a sealant composition of any type. Preferably it is such that once set it provides a seal of similar mechanical properties to the sound material of the flow passage.

More particularly the sealant composition may be an epoxy resin composition, suitably comprising a medium viscosity diglycidyl ether of bisphenol A of epoxy equivalent weight 195-215, filled with reinforcing filler.

This is settable by interaction with a medium viscosity, low temperature curing, moisture tolerant curing agent blended with reinforcing filler, at a mix ratio of 100:3060 and preferably 100:40, yielding upon completion of cure a material having a flexural modulus of 2000-3000 MPa and a flexural strength of 40-60 MPa at 20 C.

Claims

1. A method of providing an annular liner within a hollow body comprising providing an annular bag; locating the bag within the body; passing a settable composition into the bag so that the bag is inflated thereby and urged to expand radially whereby it is urged into contact with the hollow body at a region where a liner is required; and allowing or causing the composition to set.

2. A method according to claim 1 wherein the annular bag is mounted on a former or core to facilitate its location and to provide a reaction surface so that the inflation of the bag can provide greater forces in radially outward directions.

3. A method according to claim 2 wherein the former has a through passage, so that the assembly does not provide a complete barrier across the body.

4. A method according to claim 2 or 3 wherein the former is adapted to be removable from the annular bag after this has been inflated.

5. A method according to claim 4 wherein the former is radially retractable.

6. A method according to claim 5 wherein the former comprises an inflatable/deflatable sac.

7. A method according to any preceding claim wherein the settable composition comprises an expandable foam composition whose expansion urges inflation of the bag.

8. A method according to any preceding claim wherein inflation of the bag is urged by externally applied pressure.

9. A method according to any preceding claim wherein the annular bag has a radially outer wall portion through which the settable composition can penetrate so that it contacts the hollow body and adheres to it.

10. A method according to claim 9 wherein the portion of the bag in contact with the former is impervious.

11. A method according to claim 10 wherein the bag is formed of porous fabric whereof the portion in contact with the former has been rendered non-porous.

12. A method of providing an annular liner within a hollow body substantially as described herein with reference to and as illustrated in the accompanying drawings.

13. Apparatus for use in performing a method according to any preceding claim, comprising a former bearing an axially elongate annular bag having an inlet for passing in a settable composition.

14. Apparatus for use in providing an annular liner within a hollow body, the apparatus comprising a former and an annular bag and being substantially as described herein with reference to and as illustrated in the accompanying drawings.