GB2503353A

GB2503353A - Repair of pipes and pipelines

Info

Publication number: GB2503353A
Application number: GB201310857A
Authority: GB
Inventors: Mark Thomas William Potter
Original assignee: FERNCO ENVIRONMENTAL Ltd
Current assignee: FERNCO ENVIRONMENTAL Ltd
Priority date: 2012-06-20
Filing date: 2013-06-18
Publication date: 2013-12-25
Anticipated expiration: 2033-06-18
Also published as: GB201310857D0; AU2013279089A1; EP2864689A2; WO2013190282A2; GB2503353B; GB201210928D0; WO2013190282A3; GB2503249B; GB2503249A

Abstract

In order to repair fractures on a T joint between a primary pipe 1 and a lateral pipe 2, a top hat patch 10 of absorbent material is impregnated with curable resin and positioned on an inflatable bladder 20. The bladder 20 and patch 10 are positioned at the intersection 3 and inflation of the bladder 20 holds the impregnated patch against the intersection 2. Once the resin has cured, the resin and patch 10 form a rigid watertight layer. During the repair, absorbent strips 32 made from the same material as the patch 10 are wrapped around the brim portion 12 at either side of the tube portion 12 and impregnated with resin. Once the strips 32 are in place, elastic retaining bands 33 are placed around the strips 32. Once the resin has cured, the strips 32 overlie the bands 33 and thus the bands 33 cannot present an enduring snagging hazard.

Description

Repair of Pipes and Pipelines The present invention relates to improvements in and in relation to the repair of pipes and pipelines and in particular to the repair of junctions between a main pipeline and a lateral pipeline.

As pipes, iii particular sewer or waste water pipes, age they can develop cracks or fractures. This can be due to the deterioration of the pipe material, wear from the load flowing within the pipe or movement of the ground within which the pipe runs.

A common technique for pipe repair involves impregnating a patch in the fonn of a tube of resin absorbent material with a curable synthetic resin. The patch is then positioned on an inflatable bladder. The bladder and patch can then be positioned within the pipe at the location where the repair is required. Inflation of the bladder then holds the impregnated patch against the walls of the pipe whilst the resin cures.

Once the resin has cured, the resin and absorbent material forms a rigid watertight layer bonded to the interior of the pipe. in this way cracks or fractures of the pipe can be readily sealed.

Commonly, the bladder and patch is inserted into the pipe at a convenient entry point some distance from the repair location. In order to reach the repair location, the bladder and patch is pushed along the pipe by a wheeled crawler robot.

The robot may also be provided with a flexible cord carrying control cables and/or an air/water supply for inflating the bladder. In order to confirm the correct location has been reached before inflating the bladder, the distance travelled by the robot along the pipes is monitored, typically on the basis of wheel rotations or alternatively by use of other location tracking systems such as UPS or similar.

A particularly common location for fractures in pipes is at the joint between a primary pipe and a branch pipe, the branch pipe being typically known as a lateral pipe. If the basic technique above is used in such an area, the lateral pipe can be blocked off at the end of the repair and will need to be reopened. Additionally, this will not necessarily fix any fracture in the lateral pipe as it joins the primary pipe.

As such, these repairs are typically carried out using a T or Y shaped patch positioned on a corresponding T or Y shaped bladder, the leg of the T or Y being held down or inverted during transport along the pipe, the technique otherwise substantially as described above. As most fractures at lateral joints occur at the point where the lateral pipe connects to the main pipe, it is often sufficient (and would be more efficient in terms of materials) merely to repair the junction area rather than the full circumference of the primary pipe. This can be achieved by use of a top hat' patch comprising a tube portion and a brim portion attached around one end of the tube portion. In use, the tube portion can be inserted into the lateral pipe and the brim portion can be held against the walls of the primary pipe around the joint with the lateral pipe.

Whilst these techniques are well known and well understood, there are still some known difficulties. For instance, crawler robots are very expensive and the method of locating the robot by monitoring distance is not completely accurate, particularly where a pipe is curved and/or it' the robot's wheels slip or slide along part of the pipe. Another issue is that during the passage along the pipe resin can be lost from the impregnated patch if the patch rubs along the pipe. This lost resin may contribute to a build up of material along the pipe and present a snagging hazard.

Deposits of resin on the inside of the pipe may also hinder future pipe interior surveillance, Conversely, rubbing during travel can additionally or alternatively result in the resin picking up contamination or debris from within the pipe. This can have an impact on the bond achieved between the resin and the pipe as the resin cures.

Potentially, sufficient contamination could compromise the integrity of the repair.

The time taken to move the impregnated material to the repair location can also vary from job to job. The resin is typically comprised of two or more components that begin to cure on being mixed. The time from initial mixing to ftill cure depends upon the temperature of the material. As such, the amount of time available to correctly locate the bladder and impregnated material at the repair site or the time required for holding the inflated bladder in position may vary both due to the initial temperature of the resin components and the ambient temperature of the site.

In addition the general problems mentioned above, there are more specific issues relating to the lateral pipe repair methods. For instance, in order to maintain the top hat patch in position on the bladder during transit elastic bands are wrapped around the bladder and opposite edges of the brim. Once the resin cures, the portion of the bands overlapping the brim are incorporated into the repair but the remainder of the bands remain free in the pipe. As such they constitute a significant snagging hazard and need to be removed. This additional step renders this method impractical and expensive.

An additional problem with lateral repairs is ensuring that the T, Y or top hat patch is correctly orientated with respect to the lateral pipe before inflating the bladder. Even in a relatively straight section of pipe it can be difficult to ensure that the crawler robot does not crab slightly around the pipe during transit. Accordingly, it is common to insert a camera along the lateral pipe so that the orientation of the T, Y or top hat patch can be ascertained and if necessary adjusted before inflation. Even with this step, identifying and adjusting the orientation can be difficult.

It is thus an object of the present invention to provide apparatus and methods that at least partially overcomes or alleviates tile above problems.

Preferably, a pair of soluble ties is used to secure the patch to the bladder, one tie being provided on either side of the tube portion. In alternative embodiments other arrangements of tie may be used.

According to a first aspect of the present invention there is provided apparatus for repairing a junction between a primary pipe and a lateral pipe, the apparatus comprising: a patch having a tube portion and a brim portion attached around one end of the tube portion; an inflatable bladder having a main body and a side leg; wherein the tube portion of the patch is adapted to fit around the side leg of the bladder and wherein one or more absorbent strips are provided around the brim portion of the patch and the main body of the bladder the brim portion of the patch being secured to the main body of the bladder by one or more retaining bands provided over the or each absorbent strip.

According to a second aspect of the present invention there is provided a method of repairing a junction between a primary pipe and a lateral pipe, using an apparatus according to the fourth aspect of the present invention, the method comprising the steps of: impregnating the patch with a curable resin; fitting the patch to the bladder such that the tube portion of the patch fits around the side leg of the bladder; impregnating one or more absorbent strips with curable resin; providing said one or more absorbent strips around the brim portion of the patch and the main body of the bladder; securing the patch to the main body of the bladder by one or more retaining bands provided over the or each absorbent sfrip; inserting the impregnated patch and bladder into a pipe to be repaired; locating the impregnated patch and bladder at the junction to be repaired; aligning the side arm of the bladder with the lateral pipe; and inflating the bladder so as to press the tube portion of the patch against the walls of the lateral pipe and the brim portion of the patch against the walls of the primary pipe around the joint with the lateral pipe.

The use of retaining bands provided over absorbent strips ensures that the retaining bands are incorporated into the patch once the resin cures. As such, the retaining bands are not free to provide an enduring snagging hazard.

Preferably, one absorbent strip is provided for each retaining band. Most preferably, a pair of absorbent strips and a pair of retaining bands are used to secure the patch to the bladder, one absorbent strip and one retaining band being provided on either side of the tube portion. In alternative embodiments other arrangements of one absorbent strips and retaining bands may be used.

In addition to or alongside each said absorbent strip and retaining band a wire tie may be provided to thither secure the patch relative to the bladder. The wire tie may be adapted to snap once inflation of the bladder commences.

The absorbent strip is preferably formed from the same material as the patch.

The retaining band may be an elastic band.

The resin may comprise a water-glass based polysilicate. Typically such a polysilicate may comprise a blend of silicate resin and polyurethane resin. The patch may be formed from an absorbent felt material. The felt may be formed from glass fibre or any other suitable fibre.

The tube potion of the patch may be orientated substantially perpendicular to the brim portion. Alternatively, the tube potion of the patch may be orientated at a substantially oblique angle to the brim portion. Accordingly, the patch may be adapted to a T or Y type lateral junction.

The tube portion of the patch may be provided with a marker indication on its outer surface. Preferably, the marker indication is aligned with the axis of the tube portion. The marker indication can help with alignment of the tube portion relative to the lateral pipe. The marker indication may be a prominently coloured or shaded line on the tube portion. The marker indication may be provided by a dyed, inked or painted area of the tube portion. Additionally or alternatively, the marker indication may be provided by stitching on the tube portion. In embodiments wherein the patch has a marker indication, the method may involve the additional steps of: aligning the marker indication with the axis of the main body of the bladder before securing the patch to the main body of the bladder.

The apparatus may be provided with a protective sheath for use when inserting and positioning the apparatus within the pipe. The sheath may comprise a tube provided with a series of eyelets around each open end, the eyelets at a first end being reinforced the eyelets at a second end not being reinforced. The eyelets at the first end may be reinforced by bonding an additional layer of material to the sheath around the eyelets. The additional layer may be comprised of the same material as the rest of the sheath or of a different material.

The sheath may be transparent or substantially transparent. Typically, the sheath is fonned from a plastic material such as polythene (polyethylene) or the like.

In some embodiments, the sheath may be formed from a soluble material such as PYOR.

In such embodiments, the method may include the step of placing the sheath over the impregnated patch and bladder before inserting the impregnated patch and bladder into the pipe. The step of placing the sheath over the impregnated patch and bladder may include threading a tie through the eyelets of the second end of the sheath; and tightening said tie to secure the sheath to the bladder. The tie may be a conventional cable tie but is preferably a soluble tie. This step may further include attaching an elongate flexible member to the reinforced eyelets of the first end of the sheath. The elongate flexible member may be directly passed through the reinforced eyelets or may be attached to a connector device which is itself passed through the reinforced eyelets. A suitable elongate flexible member may be formed from string, rope, cord or the like. A suitable connector device may comprise a hook, loop or karabiner.

Preferably, the second end of the sheath is secured to the bladder beyond the patch. The second end of the sheath is preferably secured over the end of the bladder that will be inserted into the pipe first. The protective sheath may be provided with a number of ventilation apertures along its length. The ventilation apertures can enable the dissipation of heat from within the sheath thus maintaining the pre-determined working life and curing time.

In such embodiments, the method may include the step of removing the sheath from the impregnated patch and bladder. This step may take place either immediately before or immediately afler the step of aligning the side arm of the bladder with the lateral pipe. The removal step may be achieved by pulling on the elongate flexible member attached to the eyelets of the first end of the sheath. Since the eyelets at the second end of the sheath are not reinforced, they will tear when sufficient force is applied by pulling on the elongate flexible member allowing the sheath to be released.

The flexible insertion rods may be connected together end to end. The flexible insertion rods may be formed from steel or other suitable metal or material. In addition to flexible insertion rods one or more spring coils may be provided. The spring coils may be connected between two rods. In this manner, particularly sharp bends in the pipeline may be negotiated more easily. In particular, a spring coil may be provided between the end rod and the bladder. This facilitates insertion into a pipe from a manhole of restricted size.

In such embodiments, the method may include the steps of connecting one or more such rods together. The method may then involve the further step of pushing the impregnated patch and bladder to the repair location using the rods. The step of aligning the side arm of the bladder with the lateral pipe, may involve rotating the rod or rods. This will then result in corresponding rotation of the impregnated patch and bladder. This is much simpler, more cost effective, and more intuitive, than manoeuvring a crawler robot within a pipe to correct the orientation.

The resin may comprise two components, which when mixed provide a curable resin. The components may be supplied in separate containers or in separate sections of a single container, Preferably, the components are supplied in a single bag separated into two sections by a sealing clip. This allows for the removal of the clip to facilitate kneading of the bag to mix the resin. Beneficially, such a container removes the need for separate component containers, measuring means or mixing means.

The separate containers or the separate container sections may be provided with a temperature sensing means. The temperature sensing means may be operable to respond to variations in the temperature of the resin components, container or container sections and may be provided with indicator means operable to output an indication thereof By monitoring the temperature of the resin components and the ambient temperature, a user can determine the average working time, pot-life' or likely curing timescale of the resin. Preferably, the indicator means may comprise one or more areas of thermochromatic material printed or otherwise disposed on to the substrate. The therrnoehromatic mater al may be a thennochromatic inic and may be of the liquid crystal or leuco dye type. The thermochromatic areas may be shaped or otherwise adapted to indicate their transition temperature. The indicator means nay frirther be provided with indications of the likely product lifespan or curing time.

These indications may be in the fonn of a table. Preferably, the indicator means are provided on the exterior of the container or container section. The indicator means may be affixed to the container or container section by a suitable adhesive. In some embodiments, the temperature sensing means may comprise a probe projecting into the resin component and connected to the indicator means provided on the exterior of the container or container section.

In an alternative embodiment, the indicator means may comprise an alphanumeric display.

According to a third aspect of the present invention there is provided a kit of parts for implementing the method of the second aspect of the present invention the kit comprising: a patch having a tube portion and a brim portion attached around one end of the tube portion; an inflatable bladder having a main body ann a side leg; one or more absorbent strips; and one or more retaining bands.

The kit of the third aspect of the present invention may incorporate any or all features of the first or second aspects of the present invention, as desired or as appropriate.

The kit may additionally incorporate any one or more of: one or more protective gloves; one or more ground sheets or trays for use in applying the resin to the patch; a resin spreader; a protective sheath; one or more conventional cable ties; an elongate flexible member; one or more flexible insertion rods; an inflation hose for connection to inflate tile bladder; a compressor for use with an inflation hose to inflate the bladder; an ambient temperature sensor; a twin air supply control system; one or more pre-measured resin bags; one or more wire ties; one or more strips of absorbent material; one or more protective polythene (polyethylene) or PVOH tubes; one or more rubber bands; polythene (polyethylene) or PVOH stretch wrap; an outer box or an outer box with a waxed interior; one or more anti-bacterial wipes or gel paclcs; or infonnation leaflet.

The patch of the kit may cornprse: a tube portion and a base portion attached around one end of the tube portion wherein the tube portion is provided with a marker indication on the outer surface of the tube portion, the marker indication being aligned with the axis of the tube portion.

The provision of the marker indication can help with alignment of the tube portion relative to the lateral pipe. In particular, a user may align the marker indication with the axis of the main body of the bladder before securing the patch to the main body of the bladder.

The marker indication may be prominently coloured or shaded line on the tube portion. The maricer indication may be provided by a dyed, inked or painted area of the tube portion. Additionally or alternatively, the marlcer indication may be provided by stitching on the tube portion.

The base portion may comprise a base tube so as to provide a T or Y tube patch. Alternatively, the base portion may comprise a brim so as to provide a top hat type patch.

In order that the invention is more clearly understood it is described ftrther below by way of example only and with reference to the accompanying drawings: Figure 1 is a schematic view of al joint between a lateral pipe and a primary pipe; Figures 2a-2b are illustrations of a patches according to the present invention for use in repairing pipe joints of the type shown iii figure 1.

Figures 3a-3 e are illustrations of an implementation of the present invention; Figure 4a is a schematic view of a sheath for use in the present invention; Figure 4b shows the sheath in use in implementations of the present invention ofFigure3; and Figure 5 shows a resin container according to the present invention.

Turning now to figure 1, a T joint between a primary pipe I and a lateral pipe 2 is shown. The majority of fractures of such joints occur at the intersection 3 (shaded) of the lateral pipe 2 and the primary pipe 1. In order to repair fractures of this type, a patch 10 of absorbent material is impregnated with curable resin. The patch 10 may typically be comprised of fibreglass felt. The curable resin may typically be a water-glass based polysilicate. -12-

The patch 10 is then positioned on an inflatable bladder 20. The bladder 20 and patch 10 can then be positioned at the intersection 3 where the repair is required.

Inflation of the bladder 20 then holds the impregnated patch against the walls of the intersection 2 whilst the resin cures. Once the resin has cured, the resin and patch 10 form a rigid watertight layer bonded to the interior of the intersection 3, in particular coverng or penetiating into the cavities mid displaced/brolcen joint.

In the present invention, as is shown in figure 2a, the patch 10 is of a top hat type comprising a tube portion 12 and a brim portion 11. The tube portion 12 is adapted to fit the lateral pipe 2 and the brim portion 11 is adapted to be held against the interior of the primary pipe 1 in the vicinity of the intersection 3. The patch is further provided with a marker indication 13 in the form of a line running parallel to the axis of the tube portion 12. The marker indication 13 can be used to help align the tube portion 12 with the lateral pipe 2.

It is also possible to provide a marker indication 13 on an alternative form or patch 1 Ob (shown in figure 2b) comprising a base tube portion 1 lb and a tube portion 12b. Such a patch lOb can be used in the present invention or with known methods of pipe repair utilising a T or Y type patch.

The bladder 20, as is shown in figure 3, cornprses a main body 21 and a side leg 22. The main body 21 and side leg 22 are each substantially cylindrical and adapted to be inflated from a first circumj'erence being significantly narrower than the corresponding pipe 1, 2 to a second circumference at least equal to the circumference of the corresponding pipe 1, 2 such that the patch 10 can be pressed against the intersection 3. -13-

In order to effect a pipe repair, the patch 10 is impregnated with a liquid resin.

The patch 10 is subsequently positioned on the bladder 20 such that the side arm 22 projects through the tube portion 12 (figure 3a). The patch 10 is then secured to the bladder 20 by use of absorbent strips 32 made from the same material as the patch (figure 3b). The strips 32 are wrapped around the brim portion 12 at either side of the tube portion 12 (figure 3b), Similarly to the patch 10, the strips 32 are impregnated with resin. Once the strips 32 are in place, elastic retaining bands 33 are placed around the strips 32 (figure 3d). Optionally, wire ties 34 may also be provided around the strips 32 (figure 3c). In order to facilitate the travel along pipe 1, the side leg 22 and tube portion 12 may be bent over as is shown in figure 3e.

The patch 10 and bladder 20 can then be inserted into the primary pipe I and located adjacent to the lateral pipe 2. In the present invention, the bladder 20 can be pushed along pipe I by means of one or more flexible insertion rods (not shown) formed from steel or other suitable metal. The bladder 20 is connected to the rods by way of a T-bar fitting (not shown). Wheels 23 allow the bladder 20 to move along pipe 1 with minimal resistance. In order to facilitate the travel along pipe I, the side leg 22 and tube portion 12 may be bent over as is shown in figure 3d.

Upon reaching the intersection 3, the alignment of the patch 10 is checked by use of a camera inserted along pipe 2. In this context, the marker indication 13 provides considerable assistance in quicidy and accurately ascertaining the alignment of the patch. If the patch 10 is misaligned, the flexible insertion rods may be rotated, as necessary, so as to rotate the bladder 20 and, in turn, the patch tO.

Once the patch 10 is positioned and aligned correctly relative to the intersection, the bladder 20 is inflated. The inflation presses the patch 10 against the intersection 3. As the bladder 20 inflates, the bands 33 hold the patch 10 against the bladder 20. Subsequently, the resin cures enabling the combination of the patch 20 and the resin to form a watertight repair to the intersection 3. The bladder 20 may then be deflated and removed. One or more elongate flexible members may be attached to the bladder to facilitate such removal.

Once the resin has cured, the strips 32 overlie the bands 33. As such the bands 33 cannot present an enduring snagging hazard. If wire ties 34 are provided they typically snap as bladder 20 inflates. The wire ties 34 will then either be covered by the strips 32 or, if they break free, will be swept away once water is reintroduced to the pipe 1, thereby not presenting an enduring snagging hazard.

hi order to prevent unwanted contamination of the pipe 1 or resin by the patch rubbing against the inside of the pipe 1 during insertion and travel, a sheath 40 may be provided. The sheath, as shown in figure 5a, comprises a substantially transparent plastic tube having reinforced eyelets 41 provided at a first end and urnreinforced eyelets 42 provided at a second end. A tie 43 (soluble or conventional) may be threaded through the eyelets 42 and then secured around an end 24 of the bladder 20 as is shown in figure 4b.

A karabiner 44 may be threaded through the reinforced eyelets 41. A cord 45 can be connected to the karabiner 44. Once the patch 10 is positioned and aligned correctly relative to the intersection 3, the sheath 40 can be removed by pulling on cord 45. Exerting sufficient force on the cord causes the eyelets 42 to tear and thus allows the sheath to be removed.

Turning now to figure 5, a resin container 50 in the form of a bag is shown the bag has two sections 51, 52 separated by a sealing clip 53. Each section 51, 52 -15-contains a separate component of the resin. Once the clip 53 is removed, the two components can be mixed by kneading the bag 50.

The bag is additionally provide with temperatures sensing means 60. The temperature sensing means 60 may comprise an indicator means 62 operable to respond to the temperature of the bag 50 and/or its contents. The indicator means 62 may be directly reactive to the temperature of the bag 50. Alternatively, the indicator means 62 may be provide with a probe 61 which passes through the bag into the resin component to provide a measure of the temperature of the component. The indicator means 62 is retained on the bag 50 by a suitable adhesive.

Typically the indicator means 62 comprise one or more areas of thermochromatic material printed or otherwise disposed on a substrate. The thermochromatic areas may be shaped or otherwise adapted to indicate their transition temperature and hence the temperature of the resin components.

The user of the resin can thus check tile temperature of the resin components using the temperature sensing means 50 and can separately check the ambient temperature. This will provide the user with an indication of the curing timescale for the resin and/or the overall life time of the resin. In some embodiments, a table of curing timescales for specified component and/or ambient temperatures can be provided on a label (not shown) placed on tile bag.

It is of course to be understood that the invention is not to be restricted to the details of the above embodiments which are described by way of example only,

Claims

Claims 1. An apparatus for repairing a junction between a primary pipe and a lateral pipe, the apparatus comprising: a patch having a tube portion and a brim portion attached around one end of the tube portion; an inflatable bladder having a main body and a side leg; wherein the tube portion of the patch is adapted to fit around the side leg of the bladder and wherein one or more absorbent strips are provided around the brim portion of the patch and the main body of the bladder, the brim portion of the patch being secured to the main body of the bladder by one or more retaining bands provided over the or each absorbent strip.
2. An apparatus as claimed in claim 1 wherein one absorbent strip is provided for each retaining band.
3. An apparatus as claimed in claim 1 or claim 2 wherein a pair of absorbent strips and a pair of retaining bands are used to secure the patch to the bladder, one absorbent strip and one retaining band being provided on either side of the tube portion.
4. An apparatus as claimed in any preceding claim wherein a retaining band a wire tie maybe provided to further secure the patch relative to the bladder.
5. An apparatus as claimed in claim 3 wherein the wire tie is adapted to snap once inflation of the bladder commences.
6. An apparatus as claimed in any preceding claim wherein the absorbent strip is formed from the same material as the patch.
7. An apparatus as claimed in any preceding claim wherein the retaining band is an elastic band.
8. An apparatus as claimed in any preceding claim wherein tube potion of the patch is orientated substantially perpendicular to the Lim portion or is orientated at a substantially oblique angle to the brim portion.
9. An apparatus as claimed in any preceding claim wherein the tube portion of the patch is provided with a marker indication on its outer surthee.
10. An apparatus as claimcd in claim 9 wherein the marker indication is aligned with the axis of the tube portion.
11. An apparatus as claimed in claim 9 or claim 10 wherein the marker indication is prominently coloured or shaded line on the tube portion.
12. An apparatus as claimed in any preceding claim wherein the apparatus is provided with a protective sheath for use when inserting and positioning the apparatus within the pipe, the sheath coniptising a tube provided with a series of eyelets around each open end, the eyelets at a first end being reinforced the eyelets at a second end not being reinforced.
13. An apparatus as claimed in claim 12 wherein the second end of the sheath is secured to the bladder beyond the patch.
14. An apparatus as claimed in claim 12 or claim 13 wherein the protective sheath is provided with a number of ventilation apertures along its length.
15. An apparatus as claimed in any preceding claim wherein the apparatus includes one or more flexible insertion rods.
16. An apparatus as claimed in claim 15 wherein the apparatus includes one or more spring coils
17. An apparatus as claimed in claim 16 wherein the bladder is adapted to be connected to the rods by way of a T-bar fitting or a crank winding handle. -18-18. A method of repairing a junction between a primary pipe and a lateral pipe, using an apparatus according to any preceding claim, the method comprising the steps of: impregnating the patch with a curable resin; fitting the patch to the bladder such that the tube portion of the patch fits around the side leg of the bladder; impregnating one or more absorbent strips with curable resin; providing said one or more absorbent strips around the brim portion of the patch and the main body of the bladder; securing the patch to the main body of the bladder by one or more retaining bands provided over the or each absorbent strip; inserting the impregnated patch and Madder into a pipe to be repaired; locating the impregnated patch and bladder at the junction to be repaired; aligning the side arm of the bladder with the lateral pipe; and inflating the bladder so as to press the tube portion of the patch against the walls of the lateral pipe and the brim portion of the patch against the walls of the primary pipe around the joint with the lateral pipe.19. A method as claimed in claim 18 wherein if the patch has a marker indication, the method involves the additional steps of aligning the marker indication with the axis of the main body of the bladder before securing the patch to the main body of the bladder.20. A method as claimed in claim 18 or claim 19 wherein the method includes the step of placing a sheath over the impregnated patch and bladder before inserting the impregnated patch and bladder into the pipe.21. A method as claimed in claim 20 wherein the step of placing the sheath over the impregnated patch and bladder includes threading a tie through the eyelets of the second end of the sheath; and tightening said tie to secure the sheath to the bladder.22. A method as claimed in claim 20 or claim 21 wherein the method includes the step of removing the sheath from the impregnated patch and bladder either immediately before or immediately after the step of aligning the side arm of the bladder with the lateral pipe.23. A method as claimed in claim 22 wherein the removal step is achieved by pulling on the elongate flexible member attached to the eyelets of the first end of the sheath.24. A method as claimed in any one of claims 18 to 23 wherein the method includes the steps of connecting one or more flexible insertion rods together pushing the impregnated patch and bladder to the repair location using the rods.25. A method as claimed in any one of claims 18 to 24 wherein a spring coil is connected between two rods or between the end rod and the bladder.26. A method as claimed in claim 25 wherein the step of aligning the side arm of the bladder with the lateral pipe, involves rotating the rods.27. A kit of parts for implementing the method of any one of claims 18 to 26, the kit comprising: a patch having a tube portion and a brim portion attached around one end of the tube portion; an inflatable bladder having a main body and a side leg; one or more absorbent strips; and one or more retaining bands.28. The kit of claim 27 additionally incorporating any one or more of: one or more protective gloves; one or more ground sheets or trays for use in applying the resin to the patch; a resin spreader; a protective sheath; one or more -20 -conventional ties; an elongate flexible member; one or more flexible insertion rods; an inflation hose for coimection to inflate the bladder; a compressor for USC with an inflation hose to inflate the bladder; an ambient temperature sensor a twin air supply control systcm; one or more prc-measurcd resin bags; one or more wire ties; one or more strips of absorbent material; one or more protcctive polythenc (polyethylenc) or PVOH tubes; onc or more rubber bands; polythene (polyethylene) or PVOH stretch wrap; an outer box or an outer box with a waxed interior; one or more anti-bacterial wipes or gel packs; or information leafict.29. The kit of claim 27 or claim 28 wherein the patch comprises: a tube portion and a base portion attached around one end of the tube portion wherein the tube portion is providcd with a marker indication on the outer surface of the tube portion, the marker indication being aligned with the axis of the tube p0 it ion.30. The kit of claim 29 whercin the marker indication is a prominently coloured or shaded line on the tube portion.31. The kit of claim 29 or claim 30 wherein the marker indication is provided by a dycd, inked or paintcd area of thc tube portion.32. The kit of claims 29 to 31 wherein the marker indication is provided by stitching on the tube portion.33. The kit of claims 29 to 32 wherein the base portion comprises a base tube so as to provide a T or Y tube patch.34. The kit of claims 29 to 33 wherein the base portion comprises a brim so as to provide a top hat type patch.