GB2252808A

GB2252808A - Methods and apparatus for pipe lining

Info

Publication number: GB2252808A
Application number: GB9202611A
Authority: GB
Inventors: Malcolm William Birch; George Philip Marshall
Original assignee: North West Water Ltd
Current assignee: North West Water Ltd
Priority date: 1991-02-12
Filing date: 1992-02-07
Publication date: 1992-08-19
Anticipated expiration: 2012-02-07
Also published as: GB2252808B; GB9102951D0; GB9202611D0

Abstract

A pipe 10, e.g. oil, water or other pipe, is lined with a plastics liner pipe 11 which is pulled into the pipe 10 through a swaging die 12 to reduce the diameter of the liner 11 which expands sideways in the pipe 10. A liner gripper device 17 is urged forwards by ram 22 to move a trailing portion of liner 11 forwards overcoming resistance, for example of projections 15. The ram 22 can pull the die 12 off the pipe 10 by pushing on device 17 and thus on liner 11. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO METHODS AND APPARATUS FOR PIPE LINING This invention relates to methods and apparatus for pipe lining.

British Patent Specifications 2225406 and 2218491 describe methods and apparatus for lining a pipe by reducing a liner pipe in diameter, and drawing the reduced diameter pipe into the pipe to be lined, the liner pipe recovering in diameter in the pipe to be lined.

According to one aspect of this invention a method of lining a pipe comprises moving a liner pipe through a die to reduce the diameter of the liner pipe, moving the reduced diameter liner pipe into the pipe to be lined, the liner pipe recovering in diameter in the pipe to be lined, and urging a trailing portion of the liner pipe forwards whilst the liner pipe is recovering in diameter.

The liner pipe may be moved into the pipe to be lined by pulling on a leading portion of the pipe, and releasing the pull after the trailing portion has been urged forwards.

The method may include providing urging means for effecting the urging, and using the urging means to move the die away from the pipe to be lined.

According to another aspect of this invention apparatus for use in pipe lining comprises a die, means for gripping a liner, means for urging the gripping means towards the die to move the liner through the die, and a connection between the die and the urging means permitting movement of the die towards the gripping means under the action of the urging means.

The movement may be under the action of the urging means on the gripping means.

The invention may be performed in various ways and one specific embodiment with possible modifications will now be described by way of example with reference to the accompanying diagrammatic drawings, in which: Fig. 1 is a section through apparatus for lining a pipe; Fig. 2 is a view in a different position; and Fig. 3 shows operation of pipe lining.

A pipe 10 to be lined, for example a water, oil or other pipe, which may be underground, receives a plastics liner pipe 11. The external diameter of pipe 11 before insertion is greater than the internal diameter of the pipe 10.

The liner pipe 11 is pulled through a swaging die 12 mounted on the end of the pipe 10 which reduces the diameter of the pipe 11. When the tension in the pipe 11 is released this allows the pipe 11 to recover its diameter (i.e. expand) within the pipe 10 into close lining engagement with the inner surface 14 of the pipe 10. During this expansion, the length of the pipe 11 is reduced. The die 12 can be a split die i.e. a die in two or more laterally separable parts. In one form of pipe lining indicated generally in Fig. 3, a pipe 10 to be lined is beneath ground level 51, a winch 52 pulls the liner pipe 11 through the die 12 from a supply, the die and winch being located in pits 8,9.

However, the surface 14 may have projections 15 indicated schematically and these may interfere with or distort the required expansion of the liner pipe 11 by interfering with or preventing the associated reduction in length of the pipe 11.

Also, there may be difficulties associated with removal of the die from the liner. In the present case, the liner 11 is pulled by the winch through the pipe 10 and through a push-pull device 17 which can be operated to grip the liner 11 and to urge the line 11 forwards.

The device 17 has two or more parts 18, 19 which can be brought into gripping position on the pipe 11 and released after use by a ram 20.

The die 12 is mounted on a carriage 21 as is a ram 22 which can urge device 17, and thus the gripped liner 11, towards the pipe 10 and move device 17 away from the pipe 10 on release of the grip. The gripper 18,19,20 is also mounted on the carriage 21 in a manner permitting the die and carriage to move relative to the gripper as indicated by connection 30a.

When the winch has pulled the liner 11 into the pipe 10 with device 17 open, the ram 20 is energized to close grippers 18, 19 and then the ram 22 is energized to urge the device 17 towards the pipe 10 and thus move the gripped liner 11 through the die and further into the pipe 10 overcoming the resistance provided by projections 15. When the liner 11 can be pushed no further, continued operation of the ram 22 will move the ram cylinder 30, the carriage 21 and the die 12 to the right in Fig. 1 thus moving the die 12 off the pipe 10 (Fig.2). The liner 11 can then be severed between the pipe 10 and the die 12.

The winch pull can then be released from the front end of the liner 11. This will allow a forward part of the liner 11 to expand sideways if it has not already done so.

The liner pipe 11 is of a suitable memory retaining thermoplastics e.g. polyolefin, polyamide, polyviny chloride, acrylonitrile butadiene styrene e.g. polyethylene.

If desired an expansion device can be pulled through the liner pipe 11 during the recovery stage, to urge the liner 11 into engagement with the pipe 10.

Before or after cutting of the liner between the pipe 10 and the die 12, the liner 11 can be cut on the oppposite side of device 17 to the pipe 10 and then the device 17 and ram 22 repeatedly operated to move the device 17 and die 12 lengthwise along and off the cut end of the liner.

Claims

1. A method of lining a pipe comprising moving a liner pipe through a die to reduce the diameter of the liner pipe, moving the reduced diameter liner pipe into the pipe to be lined, the liner pipe recovering in diameter in the pipe to be lined, and urging a trailing portion of the liner pipe forwards whilst the liner pipe is recovering in diameter.

2. A method as claimed in claim 1, in which the liner pipe is moved into the pipe to be lined by pulling on a leading portion of the pipe, and releasing the pull after the trailing portion has been urged forwards.

3. A method as claimed in claim 1 or claim 2, comprising providing urging means for effecting the urging, and using the urging means to move the die away from the pipe to be lined.

4. A method of lining a pipe substantially as hereinbefore described.

5. Apparatus for use in pipe lining comprising a die, means for gripping a liner, means for urging the gripping means towards the die to move the liner through the die, and a connection between the die and the urging means permitting movement of the die towards the gripping means under the action of the urging means.

6. Apparatus as claimed in claim 5, in which movement of the die towards the gripping means is under the action of the urging means on the gripping means.

7. Apparatus for use in pipe lining substantially as hereinbefore described with reference to and as shown in Figs. 1 and 2 of the accompanying drawings.