GB2475482A - Method and apparatus for cutting slots in a pipeline - Google Patents

Abstract

The present invention relates to a product and process whereby broken and defective conduits such as underground pipelines, and in particular 1 and drains can be made permeable without the need to excavate and replace the drains. This allows remedial repair work to be carried out without the entire pipe being replaced. In particular the invention relates to a method using a rotating blade for cutting slots in the wall of a lined or unlined pipeline from the inside out and apparatus for the same.

Description

Method and apparatus for creating apertures in a pipeline The present invention relates to a product and process whereby broken and defective conduits such as underground pipelines, and in particular land drains can be made permeable without the need to excavate and replace the drains. This allows remedial repair work to be carried out without the entire pipe being replaced.

It is well known to provide drainage pipes, known as land drains, where the pipeline is provided underground. One area where this is common is when providing drainage for railway tracks. In this case the pipeline material is itself non-permeable (typically made of clay), therefore in order to act as a drain it is either provided with apertures in the form of holes or slots that allow any water sitting above the pipeline to drain into it and away, or sections of the pipe are not fully joined to each other leaving space for water to drain in.

However, once the pipeline has been in place for some time it typically requires maintenance and repair. This can be because of general erosion, structural failure or because the apertures present in the pipeline become blocked with silt and other debris reducing the influx of water into the pipeline. Usually, the cost of rehabilitating track drainage is prohibitively high due to the high cost of manually undertaking this work on the railway, which includes the need to close the section of track to be repaired and digging out/excavating at least portions of the pipeline for replacement. In view of this, remedial work is often left until the situation is critical and a pipeline is in danger of collapse.

There are other areas where similar problems occur, such as pipelines in landfill sites etc. In order to mitigate some of the problems associated with the above typical method of repairing underground pipelines, methods have been developed which allows the pipeline to be repaired in situ. An example of this can be seen in GB1340068 which describes a method where a flexible laminate is inserted through a section of pipeline and fluid pressure is used to force it against the inner wall. This method does not require the entire pipeline, or portion of pipeline that is being repaired to be excavated. Whilst useful, the problem with this methodology is that lining the inner surface with a laminate material, which is typically waterproof, prevents the ingress of fluid into the pipe as any apertures are then covered.

Previously, the inventors have described a method which utilises a pipeline pig (a relatively small vehicle that can be propelled, or which travels through, a pipeline) which travels through the pipeline. The pig is provided with a number of cutters and, once the pipeline has been lined, the cutters are used to drill a number of holes through both the newly inserted liner and the pipe. This has been found to be a significant improvement over previous methods in that it avoids the need for excavation of the pipeline and both strengthens and selectively permeablises the pipeline. There are however still drawbacks, as the track will still need to be closed for a significant period of time whilst the pig travels through the pipeline drilling a number of holes at regular intervals.

The present invention aims to obviate or mitigate all or some of the

problems associated with the prior art.

According to the present invention there is provided a method of making a pipeline permeable, comprising the steps; (a) sending a pipeline pig through the pipeline, the pig comprising a rotating cutting blade; and (b) locating the rotating cutting blade against an inner surface of the pipeline; and (C) using the rotating blade to cut a slot in the pipeline wall to thereby provide a permeable pipe.

Advantageously, cutting a slot or elongate aperture in the pipeline wall allows a greater ingress of water (or gas) than cutting a plurality of holes in the pipeline wall. This means that a slot is only required to be cut at less frequent intervals along the pipe, whereas it would be necessary to cut holes in the pipe at much closer intervals to obtain the same water (or gas) ingress. As the slots need to be cut less often than the holes and the cutting on one slot requires only a single cutting operation, the entire process is much quicker. In addition, no excavation of the pipe is required.

Optionally, the method may also comprise the initial step of; (a') inserting a liner through at least a portion of the pipe, the liner being arranged to contact a wall of the pipe.

Including this step allows for the repair of existing pipelines as the initial lining step strengthens the pipe and the newly strengthened pipe is then made permeable by the cutting of slots.

When the initial lining step (a') is included, when the rotating cutting blade is located against an inner surface of the pipeline in step (b) it is in fact located against an inner surface of the liner.

When the initial lining step (a') is included, when the rotating blade is used to cut a slot in the pipeline wall in step (c) it is in fact cutting through both the liner and the pipeline wall.

Preferably the liner is a UV cured, glass reinforced, and polyester resin liner.

Lining the pipeline using a UV liner is much faster and more efficient than other lining techniques as the equipment has been made in such a way as to be easily transported onto tracks and manoeuvred to the work site. The same would apply if we were working on a motorway, off road or in a busy highway.

Preferably the lining material is encapsulated so that no resin can escape during the ling process.

Advantageously, no special precautions such as wearing protective clothing are required to handle encapsulated lining material. Furthermore, as the outer lining material encapsulates the polyester resin this prevents the escape of odours, particularly styrene vapours.

Optionally, the lining material is pulled into position with simple winch machinery.

Preferably the liner is forced against the pipeline wall by fluid pressure.

Most preferably the liner is inflated with air.

Advantageously, using air to inflate the liner is a fast process, particularly when compared to using water for inflation.

In a preferred embodiment, the liner is cured by passing a UV light source through the inside of the liner whilst said liner is inflated.

Optionally, the slot is cut in the upper surface of the pipeline.

Alternatively, the slot may be cut in the side wall or base of the pipeline.

A further alternative is that the slot could be cut around a significant proportion of, or the entire, inner circumference of the pipeline In the preferred embodiment the slot is cut substantially laterally across the upper surface of the pipe.

Optionally the slot removes a surface area of about 1 000sq mm.

Optionally the rotating blade may be moved laterally whilst cutting.

Moving the rotating blade during the cutting of the pipeline allows for a slot of greater length than the circumference or width of the blade to be cut.

In a preferred embodiment the method includes the additional steps of; (d) moving the pipeline pig to another position in the pipeline; and (e) using the rotating blade to cut another slot in the pipeline wall.

Steps (d) and (e) can be repeated until a required or predetermined number of slots have been made in the pipeline.

Optionally the method includes the step of locking the pig in a selected position prior to creating the aperture.

Preferably, the rotating blade is powered by a water-powered motor.

Preferably, the rotating blade can be raised or lowered as required.

In the preferred embodiment the rotating blade is a cutting disc.

The cutting disc can be of any diameter appropriate to the size of the internal diameter of the pipeline.

Typically, the rotating blade is supported on a central axle.

Preferably, the central axle further comprises a rotor.

In one embodiment, a jet of water is aimed at the rotor such that the rotor then spins.

As the rotor and rotating blade/cutting disc are both supported on the central axle, the rotation of the rotor causes the central axle to rotate which in turn results in the rotation of the blade/cutting disc. The system can allow for the reduction of the RPM from 25-30000 rpm to a speed at which the cutting blade is rated.

Ideally the rotor spins at 25,000 to 30,000rpm.

Preferably the rotor is provided within a casing.

According to a second aspect of the present invention there is provided a pipeline pig comprising, means for moving said pig within a pipeline in a direction substantially co-linear with the central axis of the pig; a rotating blade; and a means for moving the rotating blade towards the wall of the pipeline.

Preferably, the rotating blade is powered by a water-powered motor.

Alternatively the rotating blade can be air powered, electrically powered or hydraulically powered.

Preferably, the rotating blade can be raised or lowered as required.

In the preferred embodiment the rotating blade is a cutting disc.

The cutting disc can be of any diameter appropriate to the size of the internal diameter of the pipeline.

Typically, the rotating blade is supported on a central axle.

Preferably, the central axle further comprises a rotor.

In one embodiment, a jet of water is aimed at the rotor such that the rotor then spins.

As the rotor and rotating blade/cutting disc are both supported on the central axle, the rotation of the rotor causes the central axle to rotate which in turn results in the rotation of the blade/cutting disc.

Ideally the rotor spins at 25,000 to 30,000rpm.

Preferably the rotor is provided within a casing.

In order to provide a better understanding of the present invention, embodiments will now be described, by way of example only and with reference to the following figures in which; Figure 1 shows a cross section view of a pipeline pig according to present invention; and Figures 2a and 2b are cross-sectional illustrations of a pipeline pig, in use, with the cutting blade in the raised and lowered positions; and Figure 3 shows a perspective view of a pipeline pig according to an aspect of the present invention; and Figure 4 shows a basic diagram of a water motor that can be used according to one aspect of the present invention.

A pipeline pig I according to an embodiment of the present invention is generally depicted in figure 1. Figures 2a and 2b illustrate the pig 1 in cross section within a drainage pipe 2. Figure 3 shows a further view of the pig.

In a preferred embodiment of the present invention the drainage pipe 2 is initially lined with a UV cured, glass reinforced, and polyester resin liner 5.

The liner material is encapsulated so that no resin can escape during the process, the benefit being that no particular precautions for handling the material are then required. The liner 5, which is a tubular structure, is pulled into position/drawn through the pipe with simple winch machinery (not shown). In this embodiment lining pods are lowered onto the track via Crane or Hiab and moved to the worksite. A Glide Foil' is pulled through the pipe 2 first prior to the liner 5 being winched into place. Packers' are inserted into the ends of the liner 5, connected to an air blower' on a UV Pod to inflate the liner 5. A Light Train' is inserted into the liner 5 and a camera on the front is used to inspect the liner 5. If the check is satisfactory a computer controlled system switches on the UV lights and pulls them back through the pipe 2. The Light Train' is removed and the End Caps' are taken out. Finally the ends are cut out and the lining process is complete.

The liner 5 is then inflated with air (or another suitable gas if preferred) such that it very quickly opens to contact the inner surface of the drainage pipe 2. The inflation continues until the liner 5 fully contacts the inner surface of the pipe 2 leaving no air gaps between the outer surface of the liner 5 and the inner surface of the pipe 2. The liner 5 is then cured rapidly by the passage of a UV light source through the inside of the liner 5 whilst the liner 5 is inflated. The outer lining material encapsulates the resin preventing the escape of odours, particularly styrene vapours during curing.

Once the liner 5 is in place and cured, the pipe is provided with internal support.

Although the above method of lining the pipe is preferred due to its speed and ease, it will be well known to those skilled in the art that there are other methods and techniques for lining a pipeline and any of these could also be used.

Once the liner 5 has been cured in place (CIPP -Cured In Place Pipe) it is then necessary to create apertures/slots 6 through the liner 5 and host pipe 2 to any allow ground water (or gas) that collects around the pipe 2 to enter the pipe 2 and then drain away through the lined pipe 2 to an outfall (not shown).

A pig 1 is launched into the pipe 2 from a catch pit or other access point (not shown) and travels along the pipe 2 by means of an electric motor 16 that drives the pig backwards or forwards on powered wheels 21 as required. The pig 1 is a remotely operated vehicle which is driven along the base 3 of the pipe 2. The pig 2 may be provided with one or more cameras 4 which send images from inside the pipeline 1 back to a user to allow the user to navigate the pig 1 along the base 3 of the pipeline. The cameras 4 can also be used to inspect the inner surface of the pipeline if required and to view the cutting operation.

When the pig I is at a position/first drilling point where a slot 6 is required in the upper surface 7 of the pipe 2 a signal is transmitted and the pig 2 is locked into position via a locking arm 8. The locking system may comprises a number of pads on pneumatically driven arms which a driven radially outwards until they engage with the inner surface of the pipe 2 or liner 5. This acts to prevent unwanted radial or longitudinal movement of the pig 1 during cutting.

Once locked into position, a rotatable blade 9 is activated using a water-powered motor 10. The pig 1 has a longitudinal central axle 11 on which is supported a rotor/turbine 12 as well as the rotatable blade 9 in the form of a diamond coated cutting disc where the outer circumference of the disc forms the cutting surface. The pig also has a jet nozzle 13 which is directed toward the rotor 12. The jet nozzle 13 is connected to a section of tubing 14 which is in turn connected to a pressurised water supply, the water is generally pressurised by a pump away from the pig 1. The pump can be as simple as a large version of a Karcher pressure washer, said water supply being held outwith the pipe 2. When a signal is given, pressurised water at approximately 3,800psi is driven through the nozzle 13 and a jet of water is fired at the rotor 12 such that the rotor then spins at 25 to 30,000rpm. The rotor is provided in a casing 15 supported on the central axle 11. The water flows over the rotor 12 and out of the casing 15 and back along a water return tube 22, causing the rotor 12 to rotate.

Some of the water can also be used to cool the rotatable blade 9 in use.

As the central axle 11 also fornis the drive for the cutting disc, the rotation of the rotor 12 in turn results in the rotation of the rotatable blade 9. The water powered motor 10 works in a very similar manner to a water wheel with a stepped edge that starts to spin at very high rpm when the water hits it (as shown in figure 4).

The rotatable blade 9 is provided at one end of the pig 12 on a moveable section 17 in the form of a powered slide that allows the rotatable blade 9 to be raised and lowered as required. The pig 2 contains a worm gear 18 (a gear consisting of a spirally threaded shaft and a wheel with marginal teeth that mesh into it) with a worm wheel 19 that rotates to raise the nioveable section 17 such that the cutting the diamond coated edge of the rotating rotatable blade 9 is also raised such that it makes contact with the inner surface of the liner 5 and pipe 2. This contact results in the blade cutting through both the liner 5 and pipe to produce a slot 6 in the upper surface of the pipe 2. The worm gear is driven by a small electric motor 20 (or could also be run from the main electric motor 16).

In this embodiment the electric motors have a supply in 23 running behind the pig 2.

Notably, other cutting blades can be used which do not require a diamond coated edge.

It could be envisaged that the moveable section 17 or simply the rotatable blade 9 could allow for lateral movement as well as the up and down movement described above. This would allow for a longer slot 6 to be cut in the upper surface 7 of the pipe 2.

The pig 2 can be provided with a distance gauge (not shown) to determine how far along the pipe 2 it has travelled.

Additionally, whilst the above embodiment discusses the lining of a pipe 2 prior to the cutting of slots, which is useful when repairing a pipeline that needs strengthening before slots can be made in it, it could also be envisaged that the slots could be cut in an unlined pipe where one wishes to enhance the performance of the land drainage without the installation of a lining material. In this case, the pig would act in the same manner as described above but any reference to the liner would simply be taken to refer to the wall of the pipe.

A further embodiment of the invention utilises the abovementioned pipeline pig or similar to cut slots along the pipe at various angles (for example 0 to 90 degrees to the above described system) which would allow the removal of defective liners more easily. Additionally, long slots could be cut as may be required for slot drainage systems such as seen in car parks.

The inventors believe that we can improve productivity greatly by the cutting of one large "slot" rather than drilling a number of smaller holes.

This "slot" or elongate aperture will be cut laterally within the pipe. The "slot" will be designed to create an opening of predetermined size with just one single cutting operation. The benefit of this is that that there is only one movement to take the blade into the cutting position and one operation to cut the "slot" before retracting the blade and moving to the next position.

In many cases the positioning of the cutting disc need not be too precise.

The cutting of the "slot" will involve just one motorised drive to move the disc up, and then down on completion of the cutting operation.

The advantages of the present invention include: * increased productivity due to simplicity and speed of operation.

* ease of availability of high-pressure water.

* quiet operation of the motor.

* very low environmental impact of the process.

* ease of availability of cooling water for the cutting disc.

* simple of controls for the cutting operation i.e.up motion and then retract.

* a simple monitoring the process via a camera.

* an ability to move quickly to the next position using the motorised traction unit for transporting the cutting pig into position through the pipe * ease of measuring movement of the position of the pig so that consistent distances between "slots" can be achieved.

* increased power of the water motor; the water motor described will produce between 5 and 7.5kw compared to an air motor of similar dimensions that would be producing approx. 1.5kw of power.

* compact plant and equipment where all that is required is reel of hose, high pressure water supply, generator, control box and the pig.

* cutting one large "slot" provides an easier exit route for water (or gas) trapped within the soil and is less likely to become blocked with silt.

Various modifications may be made to the invention hereinbefore described without departing from the intended scope thereof. For example any form of blade may be used and various mechanisms for powering the pig and various components thereof can be envisaged. In addition, further gauges may be mounted on the pig to record drilling rate, speed of movement, pressures etc so the system may be optimised and fully or partially automated.

Claims (27)

1. CLAIMS1. A method of making a pipeline permeable, comprising the steps; (a) sending a pipeline pig through the pipeline, the pig comprising a rotating cutting blade; and (b) locating the rotating cutting blade against an inner surface of the pipeline; and (c) using the rotating blade to cut a slot in the pipeline wall to thereby provide a permeable pipe.
2. 2. A method as in Claim 1 further comprising the initial step of; (a') inserting a liner through at least a portion of the pipe, the liner being arranged to contact a wall of the pipe.
3. 3. A method as in Claim 2 wherein the liner is a UV cured, glass reinforced, and polyester resin liner.
4. 4. A method as in Claims 2 or 3 wherein the liner is encapsulated.
5. 5. A method as in any of Claims 2 to 4 wherein the liner is pulled into position with simple winch machinery.
6. 6. A method as in any of Claims 2 to 5 wherein the liner is forced against the pipeline wall by fluid pressure.
7. 7. A method as in Claim 6 wherein the liner is inflated with air.
8. 8. A method as in any of the previous Claims wherein the slot is cut in the upper surface of the pipeline.
9. 9. A method as in any of Claims 1 to 7 wherein the slot is cut in the side wall or base of the pipeline.
10. 1 0.A method as in any of Claims 1 to 7 wherein the slot is cut around a significant proportion of the inner circumference of the pipeline
11. 11.A method as in any of the previous Claims wherein the slot is cut substantially laterally across the upper surface of the pipe.
12. 12.A method as in any of the previous Claims wherein the rotating blade is moved in the direction of the cutting movement during cutting.
13. 13.A method as in any of the previous Claims including the additional steps of; (d) moving the pipeline pig to another position in the pipeline; and (e) using the rotating blade to cut another slot in the pipeline wall.(f) Repeating steps (d) and (e) until a required number of slots have been made in the pipeline.
14. 14.A method as in any of the previous Claims wherein the pipeline pig is locked in a selected position prior to cutting the slot.
15. 15.A method as in any of the previous Claims wherein the rotating blade is powered by a water-powered motor.
16. 16.A method as in any of the previous Claims wherein the rotating blade is raised or lowered as required.
17. 17.A method as in any of the previous Claims wherein the rotating blade is a cutting disc.
18. 18.A method as in any of the previous Claims wherein the rotating blade is supported on a central axle along with a rotor.
19. 19.A method as in Claim 18 wherein a jet of water is aimed at the rotor such that the rotor then spins.
20. 20.According to a second aspect of the present invention there is provided a pipeline pig comprising, means for moving said pig within a pipeline in a direction substantially co-linear with the central axis of the pig; a rotating blade; and a means for moving the rotating blade towards the wall of the pipeline.
21. 21.A pipeline pig as in Claim 20 wherein the rotating blade is powered by a water-powered motor.
22. 22.A pipeline pig as in either of Claims 20 or 21 wherein the rotating blade can be raised or lowered as required.
23. 23.A pipeline pig as in any of Claims 20 to 22 wherein the rotating blade is a cutting disc.
24. 24.A pipeline pig as in any of Claims 20 to 23 wherein the rotating blade is supported on a central axle.
25. 25.A pipeline pig as in Claim 24 wherein the central axle further comprises a rotor.
26. 26.A pipeline pig as in Claim 25 wherein a jet nozzle adapted to fire a jet of water is directed at the rotor.
27. 27.A pipeline pig as in any of Claims 25 to 26 wherein the rotor is provided within a casing.