AU2009212816A1

AU2009212816A1 - Method and Apparatus for the In-situ Repair of Junction Zones in Conduits

Info

Publication number: AU2009212816A1
Application number: AU2009212816A
Authority: AU
Inventors: David Richard Harrington
Original assignee: Sideliner Enterprises Pty Ltd
Current assignee: Sideliner Enterprises Pty Ltd
Priority date: 2008-08-28
Filing date: 2009-08-27
Publication date: 2010-03-18

Description

ORIGINAL Australia Patents Act 1990 Complete Specification for the Invention Entitled METHOD AND APPARATUS FOR THE IN-SITU REPAIR OF JUNCTION ZONES IN CONDUITS The invention is described in the following statement: 2 METHOD AND APPARATUS FOR THE IN-SITU REPAIR OF JUNCTION ZONES IN CONDUITS This invention relates generally to methods and apparatus for the in-situ repair of junction zones in conduits, such as sewers, drains, water 5 mains and the like. In particular, it relates to such methods employing settable resin-impregnated pre-forms which are expanded into place in a zone of a conduit to be repaired using an inflatable form. It is common for conduits which are buried, pass beneath structures, are incorporated into buildings or are otherwise difficult of 10 access to require repair. Under such circumstances, so-called 'No Dig' or 'Trenchless Technology' techniques are now almost universally employed to repair such conduits in-situ. An extensive and diverse range of methods has been proposed for the in-situ repair of such conduits. Of these, the most common is one in which a pre-form of a suitable absorbent 15 reinforcement material is impregnated with a settable resin, placed upon an expandable form, positioned in a zone of a conduit to be repaired, expanded into intimate contact with the inner wall of the conduit using the inflatable form and maintained in the expanded state until the settable resin has cured. The inflatable form is then removed, leaving the cured 20 pre-form in place bonded to the inner surface of the conduit. Properly performed, the resultant repair is smooth and has minimal effect upon flow efficiency. An example of this method is that taught by Fisco in US 5,628,345. Particularly in sewer pipes and drains, it is common for fractures to 25 occur in laterals or service connections in a zone immediately adjacent the 3 mains which they join. The principal cause is differential movement between the laterals or service connections and the mains. Similarly, an extensive and diverse range of methods has been proposed for the in-situ repair of such fractures. In possibly the simplest repair method, a plastic 5 liner is installed in the main, a plug is temporarily installed in the lateral or service connection adjacent the main and a pressurised grout is introduced into the cavity between the two. When the grout has set or hardened, the plug is removed and an opening cut through the grout material and the plastic liner to restore flow in the lateral or service connection. Examples 10 of this repair method are those taught by St Onge in US 4,245,970 and Molyneux in US 4,893,389. In a second repair method, a liner of an absorbent material impregnated with a settable resin is winched into position in a lateral or service connection using a device suitably positioned in the main. The positioned liner is inflated to bring it into 15 intimate contact with the inner surfaces of the lateral or service connection and maintained in the inflated state until the settable resin has cured. The ends of the cured liner are then cut out to restore flow in the lateral or service connection. Examples of this repair method are those taught by Fisco et al in US 5,253,956 and Sigel in US 5,674,030. In a third repair 20 method, a T-shaped assembly of an absorbent material is tailored to fit the interior of a main and the adjacent zone of a lateral or service connection. The assembly is impregnated with a suitable resin, inflated to occupy the adjacent zones of lateral or service connection and main, and maintained in the inflated state until the settable resin has cured. The ends of the 25 cured assembly are then cut out to restore flow in the lateral or service 4 connection and the main. An example of this repair method is that taught by Taylor in US 5,927,341. In a fourth repair method, a liner having a closed and an open end and made from an absorbent material is impregnated with a settable resin and placed inside a launcher vessel 5 having one closed end. The open end of the liner is either sealingly fixed in coincidence with the open end of the launcher vessel which is positioned in register with the opening of the lateral or service connection. Alternatively, the open end of the liner is sealingly fixed over the opening of the lateral or service connection. Pressurisation of the launcher vessel 10 then causes the liner to be everted into the lateral or service connection, the liner being maintained in the inflated state until the settable resin has cured. The launcher vessel is then removed and the end of the cured liner cut out to restore flow in the lateral or service connection. Examples of this method of repair are those taught by Wood in US 5,393,481, 15 5,624,629 and 5,692,543; Kamiyama et al in US 5,439, 033, 5,454,401, 5,566,719 and 5,598,873; Kiest in US 5,950,682, 6,039,079 and 6,105,619; Einhaus et al in US 6,227,764; and Endoh in US 5,329,063. While all of the methods cited are well known and proven, they are operated, for the most part, with special equipment which may require a 20 high level of skill and judgement in its use. The equipment is often expensive, large and heavy, requiring multiple personnel and support vehicles for its operation. Specifically, the cited methods do not provide the level of productivity necessary to repair in a cost-effective way the large number of defects arising in conduits of small diameter in a typical 25 metropolitan sewerage or drainage system.

5 In a system taught by Harrington in Australian Provisional Patent Application No. 2007903367, a localised defect in a conduit is repaired by impregnating a suitably shaped pre-form of a suitable reinforcement material with a suitable settable resin, positioning it on an inflatable 5 mandrel, locating the mandrel in the conduit zone to be repaired, inflating the mandrel to bring the settable resin-impregnated pre-form into intimate contact with the inner surface of the conduit, maintaining inflation of the mandrel until the settable resin has cured, and deflating the mandrel and removing it from the conduit leaving the cured repair in place bonded to 10 the inner wall of the conduit. To accommodate the directional and cross sectional changes common in a typical metropolitan sewerage or drainage system, the mandrel is made such that, in its deflated state, it is small in diameter in relation to that of a conduit to be repaired and fully flexible. The repair pre-form is optionally made in tubular form and slid over the 15 mandrel or in flat form and wrapped around the mandrel. The repair pre form is optionally impregnated with settable resin on or off the mandrel. The use of a tubular pre-form impregnated on or off the mandrel is generally easier and more convenient than using a pre-form separately impregnated flat and then wrapping it around the mandrel. This is an 20 important point, as the ambient-curing resins normally used with the repair system generally have a short pot life. It is frequently more convenient to impregnate a tubular pre-form on the mandrel as this results in less inadvertent resin transfer and mess. Where on-mandrel impregnation is used, retaining bridles (see following) may be tied prior to impregnation 25 by an operator with clean hands. A release shroud of a material to which 6 the settable resin adheres poorly is positioned between the mandrel and the settable resin-impregnated pre-form. The release shroud is fixed to the leading end of the mandrel (leading in the sense of direction of entry into a conduit to be repaired) and, following curing of the repair, the mandrel is 5 deflated and withdrawn in the reverse direction by a cable attached to its trailing end. This causes the release shroud to evert and peel cleanly away from the repair, ensuring a reliable release with the application of a minimum of force and with a minimum risk of adhesion to the mandrel. Common industry practice is to secure resin-impregnated pre-forms on 10 inflatable mandrels using frangible ties, elastic bands or the like. It is well known in the industry that pre-forms secured in this way may become displaced and, particularly when traversing bends, may actually be completely detached from mandrels. To more securely retain the settable resin-impregnated pre-form on the mandrel during its positioning in a 15 conduit, retaining bridles of a suitable material are attached to the leading end of the mandrel and to the inside surface of the leading edge of the resin-impregnated pre-form. The bridles are attached to the pre-form using a hot-melt glue gun and, during removal of the mandrel from the conduit, peel away from the cured repair. To assist in positioning the resin 20 impregnated pre-form on the mandrel, self-adhesive patches of the hooked part of the Velcro® attachment system are fixed to the outer surface of the release shroud at the trailing or at both extremities of the pre-form, the hooks engaging the fibrous material of the pre-form. The inflatable body of the mandrel is optionally made of a suitable elastic material or of a non 25 elastic material, the inflation of which is limited by a non-elastic sizing 7 sleeve. The end fittings of the mandrel and their methods of fixing to the inflatable body optionally have several configurations. A positioning carriage is optionally used in positioning the mandrel and resin impregnated pre-form in a conduit to be repaired. Because of the 5 compact cross-sectional area of the mandrel of the system taught by Harrington and the ease of use of this system, it is proposed to adapt the system to perform junction zone repairs. The object of the present invention is to provide a method and apparatus (a system) for the efficient repair of localised defects in junction 10 zones in conduits of relatively smaller diameter; a system which has relatively low capital and operating costs; a system which requires only a relatively low level of skill and judgement for its operation; a system which is light, compact and substantially self-contained; and a system which requires only minimal support in terms of personnel and vehicles. 15 Importantly, to ensure cost-effective operation, the system must also permit junction zone repairs to be performed quickly and efficiently with minimal set-up time. According to the present invention, the inflatable mandrel assembly of the system taught by Harrington and described above, 20 carrying a repair pre-form impregnated with a settable resin, is transported in a launcher tube into the main requiring a junction zone repair. The launcher tube is supported on a chassis comprising, principally, skids or wheels to facilitate movement, jacking means to raise the launcher tube and secure it in place in the main, a mandrel displacement unit to displace 25 the inflatable mandrel from the launcher tube, a deflector to direct the 8 inflatable mandrel and repair pre-form from the launcher tube and into the junction zone to be repaired, and an actuator to deploy the deflector into or out of its operational configuration. The repair pre-form is impregnated in the manner described above on or off the inflatable mandrel, the 5 mandrel and pre-form are connected to the mandrel displacement unit and drawn into the launcher tube. The launcher tube and chassis are winched (or propelled by alternative means) into the main to the appropriate location and secured in place by the jacking means. The deflector is deployed to its operational position and the mandrel displacement unit 10 employed to displace the inflatable mandrel and repair pre-form into the junction zone to be repaired via the deflector. A closed-circuit television camera is positioned in the main beyond the junction zone and is used to confirm the correct positioning of the launcher tube and deflector in juxtaposition with the junction zone. Following entry of the inflatable 15 mandrel and repair sleeve into the lateral or service connection, the closed circuit television camera is used to confirm the positioning of the mandrel and repair pre-form within the repair zone, the deflector being displaced out of its operational position so as to not obscure the view of the mandrel and repair pre-form by the closed-circuit television camera. When 20 properly positioned in the junction zone, the mandrel is inflated by fluid pressure to bring the settable resin-impregnated repair pre-form into intimate contact with the inner surfaces of the lateral or service connection, the mandrel being maintained in the inflated state until the settable resin has cured. The launcher tube and chassis are then withdrawn 25 from the main, causing the inflatable mandrel to be withdrawn from the 9 lateral or service connection, the release shroud of the inflatable mandrel everting and peeling cleanly away from the cured repair in the manner described previously, thereby ensuring a reliable release. The various aspects of the present invention will be more readily 5 understood by reference to the following description of preferred embodiments given in relation to the accompanying drawings in which: Figure 1 is a longitudinal cross-sectional view of the leading end of said inflatable mandrel showing a first method of fixing said inflatable body to said end fitting; 10 Figure 2 is a longitudinal cross-sectional view of the leading end of said inflatable mandrel showing a second method of fixing said inflatable body to said end fitting; Figure 3 is a side view of the leading end of an inflatable mandrel of larger diameter with a settable resin-impregnated repair 15 pre-form fixed to it; Figure 4 is a transverse cross-sectional view on A-A of the configuration depicted at Figure 3; Figure 5 is a longitudinal view of an application of the present invention, depicting components partially in cross-section 20 and partially in schematic form; Figure 6 is a partial transverse cross-sectional view on A-A of the apparatus depicted at Figure 5; Figure 7 is a partial longitudinal cross-sectional view of an application of the present invention in a junction zone repair. 25 With reference to Figure 1, an inflatable mandrel I for use in the 10 repair of smaller conduits of a typical diameter in the range 50 to 150 millimetres comprises leading end fitting (leading in the sense of direction of entry into a conduit to be repaired) 2, trailing end fitting (not shown) and inflatable body 3, the ends of which are sealingly bonded to shanks 14 5 of said end fittings. Said trailing end fitting is identical with said leading end fitting, with the addition of an air hose connection fitting (depicted as 65 in Figure 5) and connection means allowing connection of flexible thrust means forming part of a mandrel displacement unit. To reduce weight said end fittings are preferably made hollow with the edges of their 10 inner ends made rounded or chamfered to minimise the possibility of chafing or pinching damage to said inflatable body. Release shroud 4 extends axially to cover more than the full length of said inflatable body, in the preferred embodiment, its leading end being fixed to said leading end fitting by several turns of duct tape or other suitable self-adhesive, 15 strip material (depicted as 5 in the Figure). In an alternative embodiment, said leading end of said release shroud is fixed to said leading end fitting by means of a suitable clamping band (depicted as 5a in Figure 3). In the preferred embodiment, the trailing (free) end of said release shroud is secured in place with suitable frangible tie means, said tie means taking 20 the form of a self-adhesive paper tape, such as masking tape, or a ribbon or cord of a suitable weak material. In an alternative embodiment, said trailing end of said release shroud is left free and unattached. In the preferred embodiment, said release shroud is a disposable item having an inflated diameter equal to or slightly less than that of the finished internal 25 diameter of the repair to be effected and a new one is installed on said 11 inflatable mandrel in preparation for each said repair. Said inflatable body is made from a suitable elastic polymer and is able to be safely inflated to 300% of its deflated diameter. Choker ring 6 is positioned immediately adjacent the inner ends of said end fittings and acts to constrict said 5 inflatable body at point 13, thereby preventing its bonded part from peeling away from said end fittings during inflation. Repair pre-form 7 is positioned over said release shroud and supported in position by retaining bridles 8 tied to bridle attachment fitting 9 fixed to the nose of said leading end fitting, said retaining bridles being fixed to the inner surface of the 10 leading edge of said pre-form using a hot-melt glue gun at points 10. In the said diameter range, three retaining bridles are normally provided. To provide more positive location of said pre-form on said release shroud, in the preferred embodiment, a plurality of self-adhesive patches of the hooked part of the Velcro@ attachment system (not shown) are fixed to 15 the outer surface of said release shroud in the position of the trailing extremity of said pre-form, the hooks acting to engage the inner, fibrous surface of said repair pre-form and thereby to locate said pre-form on said release shroud. Where the nature of said inner surface of said pre-form is such that said Velcro® patches attach poorly to it, a smear of a suitable 20 peelable adhesive is applied to said Velcro@ to improve adhesion. In an alternative embodiment, said self-adhesive patches of the hooked part of the Velcro® attachment system are fixed to the outer surface of said release shroud in the positions of both extremities of said pre-form. In the preferred embodiment, the leading end of said impregnated repair pre 25 form is stabilised using suitable frangible tie means (not shown), said tie 12 means taking the form of a self-adhesive paper tape, such as masking tape, or a ribbon or cord of a suitable weak material. Said tie means act to prevent said leading edge from being displaced either inwardly or outwardly during transit of a conduit. 5 An internally positioned anti-elongation cable (not shown) is provided in all said mandrels in which said inflatable body is made from an elastomeric material. Said anti-elongation cable optionally takes the form of a chain or multi-strand wire cable fixed to both leading and trailing end fittings and acts to prevent elastic extension of said mandrel 10 during inflation. In the preferred embodiment (not shown), threaded shank 11 of said bridle attachment fitting and the shank of said connection means allowing the connection of said thrust means (not shown) are extended to protrude into the interior of said end fittings and the ends of said anti-elongation cable are swaged into threaded terminal fittings (not 15 shown) which are screwed and tightened onto said extended threaded shanks. To ensure that said inflatable body is inflated evenly and consistently over all of its parts, said anti-elongation cable is made with slack in the range 100 to 150 millimetres per metre of length. Without said slack, said inflatable body may experience axial ballooning at its ends 20 during inflation. In the preferred embodiment of said mandrel, said inflatable body is made from a suitable elastic polymer material ranging in thickness from 2.0 millimetres to 8.0 millimetres and of a normal maximum length of three metres. In preferred embodiments for use in conduits in the same diameter range, said inflatable body is made from any 25 of synthetic rubber, butadiene, GRS, butyl, E P rubber, Hypalon, 13 Neoprene, Nitrile, polysulfide, fluorocarbon, fluorosilicone, silicone, urethane or polyalkylene oxide polymer. Mandrels of the present invention incorporating elastomeric inflatable bodies are normally inflated to pressures in the range 100 to 250 kPa. In the preferred embodiment, 5 said release shroud is made in tubular form from a suitable light, thin, flexible sheet polymer material including low, medium or high molecular weight polyethylene or similar cross-linked polymer material in the thickness range 0.15 to 1 millimetre and tolerating an elastic extension of 20 per cent in the approximate temperature range 5*C to 40*C. Making 10 said release shroud in tubular form ensures its eversion in a controlled and orderly manner during removal of a mandrel following completion of a repair. Where said release shroud is not made from a material to which said settable resins adhere only weakly, to aid in its said peeling detachment from said cured repair, the outer surface of said release shroud 15 is optionally treated with a suitable release agent including, talcum, natural waxes, silicone waxes or suitable mineral or non-mineral oils or greases. In the preferred embodiment, said repair liner preform is made in the following thickness ranges: CONDUIT DIAMETER (MM) PRE-FORM THICKNESS (MM) 20 50-100 2 to 3 100-200 2 to 5 200-300 3 to 6 Said preform is optionally made in single or multiple-layered material. In the preferred embodiment, for repairs in conduits up to 150mm in 25 diameter, said preform is made from a single thickness of knitted pile 14 material ranging in thickness from two to five millimetres and tolerating an elastic extension of not less than 25 per cent in both circumferential and axial senses. The said degree of elastic extension permits said preform to stretch over the inner surfaces of bends, thereby providing a wrinkle-free 5 application, an effect not achievable using non-elastic materials, such as fibreglass. In alternative embodiments, said preform is made from a similar material tolerating an elastic extension in both circumferential and axial senses in the range 20 to 40 per cent. In the preferred embodiment, said repair pre-forms for repairs in conduits in this size range are made in 10 tubular form having the same diameter as a conduit to be repaired, or smaller in the range 10% to 20%, and are impregnated with said settable resin on said release shroud prior to or following its positioning on said inflatable mandrel. The general procedure for impregnation is described in relation to Figure 3. Said retaining bridles are attached to said pre-form 15 prior to its impregnation and then tied to said leading end cable attachment fitting following positioning of said release shroud and pre-form on said mandrel. For repairs in conduits of larger diameter, said pre-form is made in the thickness range five millimetres to 10 millimetres and optionally includes layers of knitted pile material, woven reinforcement material or 20 needled felt, said layers being fused, bonded or quilted together. Such material is made in flat sheet form, is separately impregnated in its flat state and then wrapped around said inflatable mandrel on which said release shroud has been previously installed and secured in wrapped form by suitable frangible ties, elastic bands or the like. The general procedure 25 for impregnation is described in relation to Figure 3. Said retaining bridles 15 are fixed to the inner surface of the leading edge of said pre-form prior to its impregnation. With reference to Figure 2, because of the difficulty of replacing in the field an inflatable body which has been bonded to said mandrel, in an 5 alternative embodiment, the ends of said inflatable body are slipped over shanks 14 of said end fittings and secured in place by collar 12 swaged over them. Flanges 16 at the outer ends of swaged collars 12 are captured in grooves 17 and thereby act to retain said swaged collars on said end fittings. Neckings 18 of said swaged collars positioned immediately 10 adjacent the inner ends of said end fittings act to constrict said inflatable body at points 13, thereby minimising any tendency of said inflatable body to pull away from shanks 14 of said end fittings during inflation. In an alternative embodiment, collar 12 is made simply cylindrical without necking 18 and a choker ring (such as that depicted as 6 in Figure 1) is 15 positioned immediately adjacent the inner end of said end fitting to constrict said inflatable body at that point and preventing its being urged injuriously against the inner end of said collar during inflation. With reference to Figures 3 and 4, in an inflatable mandrel intended for repairing conduits in the diameter range 150 to 600 20 millimetres, inflatable body 20 is made from a strong, flexible, non-elastic sheet material considerably larger in diameter than the shanks (not shown) of end fittings 23 and are sealingly attached to said shanks by clamping bands 19. In the preferred embodiment, said end fittings are made hollow, fabricated from a suitable sheet metal material, said shanks preferably 25 being ribbed, grooved or otherwise shaped to promote adhesion and 16 sealing to them of said ends of said inflatable body. Prior to the tightening of clamping bands 19, said inflatable body is provided with one or more circumferentially-arranged folds 25 (edge of one fold depicted as 24 in Figure 3) which permit said inflatable body in its folded form to 5 approximate the diameter of said shanks of said end fittings. In the preferred embodiment, said inflatable body is made from a thin, strong, flexible, impervious material, such as seamless, polyvinylchloride lay-flat hose. In alternative embodiments, said inflatable body is fabricated from a suitable sheet material with sewn or fused and taped seams. Said 10 inflatable body can be made with a diameter considerably larger than that of said end fittings and, to limit its inflated diameter to that required for the repair of a conduit of a particular diameter, a non-elastic sizing sleeve 21 is positioned over it. During inflation, the inflated diameter of said inflatable body is limited to that permitted by said sizing sleeve. In the 15 preferred embodiment, said sizing sleeve is made from any strong, flexible, non-elastic fabric, including canvas and calico, and covers 50% to 80% of the length of said inflatable body with 50% to 20% of the trailing end of said inflatable body left uncovered. Said sizing sleeve is optionally left with its ends unsecured and retained in place by said impregnated pre 20 form which is provided with positive retaining means on said release shroud. In the preferred embodiment, the ends of said sizing sleeve are secured to said end fittings by several turns of duct tape or other self adhesive tape. Where said ends of said sizing sleeve are so secured, sufficient free length is allowed to prevent said sizing sleeve from 25 inhibiting the axial expansion of said inflatable form during its inflation.

17 In the preferred embodiment, release shroud 4 in the form described previously is installed over said sizing sleeve in the manner described previously and its leading edge secured in place on leading end fitting 23 by the application of several turns of duct tape or similar self-adhesive, 5 waterproof, strip film material (depicted as 5 in the Figure). In an alternative embodiment, the leading edge of said release shroud is secured in place on said end fitting by means of a suitable clamping band (depicted as 5a in the Figure). In the preferred embodiment, the trailing end of said release shroud is secured in place with suitable frangible tie means, said tie 10 means taking the form of a self-adhesive paper tape, such as masking tape, or a ribbon or cord of a suitable weak material. Said Velcro@ patches (typical positions indicated as 22) are fixed to said release shroud following measuring and cutting of repair pre-form 7 - as indicated previously, those positioned at the leading edge of said pre-form being 15 optional. In the preferred embodiment, a tubular said pre-form is slid over and positioned on said release shroud and impregnated in-situ. Said impregnation process comprises pouring a measured quantity of said settable resin into the annular space between said pre-form and said release shroud and then employing suitable means to knead, squeeze or 20 roll said pre-form to ensure an even distribution of resin throughout its thickness. Additional resin is applied as required to the exterior of said pre-form using a suitable brush. A particular advantage of said system is the fact that, in the case of smaller repairs, an even distribution of resin can be achieved throughout the thickness of said pre-form merely by operator 25 hand action. Upon completion of impregnation, said release sleeve and 18 said impregnated repair pre-form are installed on said inflatable mandrel. In an alternative embodiment, said release shroud and said pre-form are installed on said inflatable mandrel prior to impregnation of said pre-form. In another alternative embodiment (particularly in the case of larger 5 repairs), a flat said repair pre-form is impregnated in its flat state (using a roller, if necessary, to achieve an even distribution of said settable resin), wrapped around said release shroud which has previously been installed on said inflatable mandrel and retained in its wrapped form by suitable frangible ties, elastic bands or the like. Two or more retaining bridles 8 10 are attached to said pre-form prior to its impregnation and tied to cable attachment fitting 9 following positioning of said pre-form on said release shroud. Said patches of Velcro@ material engage the fibrous inner surface of said preform as it is positioned on said release shroud. In the preferred embodiment, the leading end of said impregnated pre-form is stabilised 15 using suitable frangible tie means, said tie means taking the form of a self adhesive paper tape, such as masking tape, or a ribbon or cord of a suitable weak material. Said tie means act to prevent said leading edge from being displaced either inwardly or outwardly during transit of a conduit. In an alternative embodiment, said leading end of said impregnated pre-form is 20 left unsecured. In an alternative embodiment (not shown) end fittings 23 are made in cylindrical form with a plurality of curved, forward or rearwardly-projecting rod members to guide said inflatable mandrel through directional changes in a conduit. Although not essential in said inflatable mandrels incorporating non-elastic inflatable bodies, in the 25 preferred embodiment, an internally positioned anti-elongation cable (not 19 shown) in the form previously described is normally provided in all said inflatable mandrels of larger diameter. Said anti-elongation cable acts to reduce the stress imposed upon the points of attachment of said inflatable body to said shanks of said end fittings during inflation. In said inflatable 5 mandrels incorporating non-elastic inflatable bodies, said inflatable bodies may be made with a diameter of up to 200% of that of said end fittings. For example, in the preferred embodiment, a said inflatable mandrel for the repair of a conduit having a diameter of 600 millimetres has end fittings of a diameter of 375 millimetres. Typical inflation pressures of 10 said inflatable mandrels of larger diameter vary from 80 kPa at 150 millimetres diameter to 40 kPa at 600 millimetres diameter. In the preferred embodiment, four said retaining bridles are used in said inflatable mandrels in the diameter range 150 to 300 millimetres. At greater diameters than 300 millimetres, five or six said retaining bridles 15 are used. With reference to Figures 5 and 6, launcher tube 26 is supported on chassis 27. Said chassis comprises side panels 27a and lower central panel 27b, all said panels being joined to form an elongated box structure, closed throughout its length except for apertures at points 28 through 20 which project wheels 29 and jacking means. In the preferred embodiment, said jacking means take the form of jacking arms 30 pivotally supported on shafts 31 passing through their bosses 34 and between said chassis panels. The lower ends of said jacking arms are formed into pads 33, the lower surfaces of which are made curved to facilitate contact with the 25 inner surfaces of main 35 at a variety of angles. In the preferred 20 embodiment, in order to achieve good frictional engagement between said jacking arms and the inner surfaces of said main, said lower surfaces of said pads are either made hard and serrated or are coated with hard asperities, such as brazed-on silicon carbide chips. Actuator 38 pivotally 5 mounted from a suitable bracket of said chassis on pivot 41 applies force to actuator arm 39 pivotally mounted from a suitable bracket of said chassis on pivot 40. Rotational displacement of said actuator arm causes simultaneous displacement of jacking arm actuation rods 36, said jacking arm actuation rods being pivotally connected to the ends of said actuator 10 arm at pivots 42 and lever arms 32 of said jacking arms at pivots 37. Displacement of said lever arms by said jacking arm actuation rods causes said jacking arms to be rotationally displaced on shafts 31, thereby causing their free ends to be displaced downwardly to bring said lower surfaces of pads 33 into contact with the inner walls of said main. Continued 15 displacement of said jacking arms causes said launcher tube and said chassis to be bodily lifted until axially arranged contact rails 43 fixed to the upper surface of said launcher tube are brought into firm contact with the upper, inner surfaces of said main. Said contact rails extend for more or less the full length of said launcher tube and are preferably joined by 20 webs 44 to prevent their spreading under the forces of said jacking process. Said launcher tube is made sufficiently robust to accommodate forces applied to it as a result of said contact rails being urged against the upper, inner surfaces of said main. Said contact rail assemblies are made in a variety of heights and are readily removed from and installed on said 25 launcher tube using a small number of quick-release fastenings (not 21 shown). In preparing said chassis and launcher tube assembly for operation, a contact rail assembly of suitable height is installed on said launcher tube to ensure that, when said chassis and launcher tube assembly is raised by said jacking means, the path defined by said deflector can be 5 brought into register with said lateral or service connection. In order to achieve good fictional engagement between said contact rails and the upper, inner surfaces of said main, the upper edges of said contact rails are either made hard and serrated or are coated with hard asperities, such as brazed-on silicon carbide chips. With said lower surfaces of pads 33 and 10 said upper edges of said contact rails in firm contact with the upper, inner surfaces of said main, said chassis and launcher tube assembly is locked securely in place in said main. In a first optional embodiment, said jacking arms are rotationally supported on horizontally arranged shafts (as depicted in Figure 5) and move in a vertical plane. In a second 15 embodiment, said jacking arms are rotationally supported on angled shafts (as depicted in Figure 6) and move in oblique planes, the latter arrangement being employed in situations requiring better positional stabilisation of said chassis and launcher tube assembly. When said jacking arms are not required to be deployed, actuator 38 is operated to 20 raise said jacking arms to a more or less horizontal position parallel with the longitudinal axis of said chassis. In a first alternative embodiment (not shown), said jacking means take the form of rams displaced downwardly, either vertically or obliquely. Said rams are optionally simple or telescopic and are extended by electrical operation of a ball screw, or by 25 fluid pressure. Contact pads provided on the ends of said rams are free to 22 align themselves with the curved internal surfaces of a conduit and, in order to achieve good fictional engagement between said pads and the inner surfaces of said main, the lower surfaces of said pads are either made hard and serrated or are coated with hard asperities, such as brazed-on 5 silicon carbide chips. In a second alternative embodiment (not shown), said jacking means take the form of lazy tongs-type struts provided with contact pads similar in arrangement to those described in the preceding paragraph. In the preferred embodiment, wheels 29 are also rotationally supported on shafts 31 with suitable washers 45 provided between said 10 jacking arm bosses, said wheels and said chassis panels. In a first alternative embodiment (not shown), said wheels are rotationally supported on separate fixed shafts. In a second alternative embodiment (not shown), said wheels are rotationally supported on separate stub shafts provided on the free ends of wheel supporting arms, said wheel supporting 15 arms being pivotally supported from said chassis and able to be displaced upwardly or downwardly by manually-operated or power-operated displacement means to adjust the height of said chassis and launcher tube assembly. In a further alternative embodiment (not shown), said jacking means are deleted and the assembly of wheels, stub shafts and pivotally 20 displaceable wheel supporting arms as described in the preceding paragraph are employed to raise said chassis and launcher tube assembly. In this embodiment, said contact rails are also deleted and arrangements similar to said jacking means are employed to contact the upper, inner surfaces of said main. In use, said wheel supporting arms are displaced 25 simultaneously and equally to set the height of said chassis and launcher 23 tube assembly and said jacking means are then displaced simultaneously and equally to lock said chassis and launcher tube assembly into said main. Displacement of both said groups is effected by actuators such as those described in the foregoing, said actuators being separately 5 controllable. The said arrangement permits the height of said launcher tube to be accurately adjusted within said main. In a further alternative embodiment (not shown), said contact rails are fixed to a suitable beam and jacking means as described in the foregoing are adapted to raise said beam and thereby bring said contact rails into contact with the upper, inner 10 surfaces of said main. In an alternative embodiment (not shown), said chassis and launcher tube assembly are raised by suitable inflatable jacking pads incorporated into the lower part of said chassis. Said jacking pads are optionally used in conjunction with said fixed or displaceable contact rails. 15 In the preferred embodiment, launcher tube 26 is supported in saddle 55 fixed to the upper part of chassis 27 and is retained in place by suitable fastenings (not shown) passing through flanges 56, 57 provided, respectively on said launcher tube and said saddle. In an alternative embodiment (not shown), said launcher tube is retained in place by 20 clamping bands which may be loosened to permit rotational adjustment of the position of said launcher tube. Deflector 58 is pivotally supported on pivot 46 and is deployed into or displaced out of its operational position (displaced-out position depicted in broken line as 59) by deflector actuator 49. Said deflector actuator is pivotally mounted to a suitable bracket of 25 said chassis at pivot 50 and the end of its actuator rod 60 is pivotally 24 connected to deflector actuation arm 47 at pivot 48. In a first alternative embodiment (not shown) in which the radial orientation of the axis of said deflector is adjusted by loosening clamping bands securing said launcher tube in place on said chassis and rotating said launcher tube, said deflector 5 actuator is pivotally mounted to a suitable bracket fixed to said launcher tube. In a second alternative embodiment (not shown), said deflector is pivotally supported from a collar which is rotationally fixed to the end of said launcher tube. Said deflector actuator is pivotally mounted to a suitable bracket fixed to said collar. In this embodiment, the radial 10 orientation of the axis of said deflector is adjusted by rotating said collar. In a first form of the said embodiment (not shown), rotation of said collar is effected by a pinion rotationally displaceable by suitable actuator fixed to said launcher tube, said pinion engaging a circular or part-circular rack fixed to said collar. In a second form of the said embodiment (not shown), 15 a coaxial skirt fixed to said collar is provided with a helical slot engaged by a suitable peg. Said peg is fixed to an axially arranged rod supported from said launcher tube, said rod being slidingly supported in suitable bearings and able to be displaced by a suitable linear actuator to effect rotation of said collar. In a third form of the said embodiment (not 20 shown), one end of a push-pull rod is pivotally connected to said collar with said rod in a more or less tangential arrangement, the other end of said rod being pivotally connected to a suitable bell crank pivotally supported from said launcher tube. Said bell crank is pivotally displaced by a suitable, axially-arranged linear actuator to apply a rotational force to 25 said collar. Actuators 38 and 49 employed to displace said jacking arms 25 and to deploy said deflector and said actuator employed to rotate said collar are optionally electrically-operated ball screw-type linear actuators or rams actuated by fluid pressure. Actuators 38 and 49 are supplied, respectively with electricity or pressurised fluid via cables or lines 51, 52 5 and 53, 54. Suitable cables or lines (not shown) supply electricity or pressurised fluid to said actuator employed to rotate said collar. In an alternative embodiment (not shown), said deflector is made with two lever arms formed on its side edges towards its free end and arranged more or less parallel to actuation arm 47, but extending in the opposed direction. 10 In this embodiment, said deflector is raised and lowered by means of suitable rods or cables pivotally fixed to said lever arms. Said rods or cables are operated by means of suitable actuators of the type described in the foregoing. In another alternative embodiment (no shown), said deflector is supported in its operational position by two breaking links. 15 Said deflector is permitted to fall to its said displaced-out position by the breaking of said links. As only a small force is required to move said breaking links to their over-centre positions and cause them to break, this is preferably performed by a plunger manually actuated via a Bowden cable or by an electric solenoid. 20 Supported inside the trailing end of said launcher tube by webs or brackets 62 is mandrel displacement unit 61. Said mandrel displacement unit is supported from said webs or brackets by suitable fasteners, permitting it to be readily removed and replaced with a unit providing greater or lesser displacement. In the preferred embodiment, the ram of 25 said displacement unit is telescopic in action and is actuated by an 26 electrically-operated ball screw or by fluid pressure. Electricity or fluid pressure is supplied to said displacement unit via one or more cables or lines 66. In an alternative embodiment (not shown), said displacement unit ram is simple in arrangement and not telescopic. The free end of said 5 ram of said displacement unit is connected via a stiffly flexible link 67 to trailing end fitting 68 of said inflatable mandrel. Said flexible link is connected to said trailing end fitting by suitable connection means 64. In the preferred embodiment, said connection means take the form of a complementary plug and socket retained together by means of a quick 10 release pin (not shown). Fluid pressure is supplied to said inflatable mandrel via line 69 connected to connection fitting 65 of said trailing end fitting. To minimise chafing of it during displacement of said inflatable mandrel, line 69 passes through fairlead 70 provided in the wall of said launcher tube. Said stiffly flexible link is made sufficiently long to 15 provide the flexibility necessary for the displacement of said inflatable mandrel into said laterals or service connections meeting said main at 30 degree, 45 degree and 90 degree junctions. A transversely arranged tow bar 73 is connected by twin cables 72 to two cable attachment points 71 provided on the leading end of said 20 chassis. A single cable connects said tow bar to a suitable winch employed to position said chassis and launcher tube assembly in said conduit. Said twin cables are sufficiently long and separated by sufficient width to permit said deflector to pivotally descend between them into its said displaced-out position (displaced-out position depicted in broken line 25 as 59). In the preferred embodiment, a single attachment point (not 27 shown) is provided at the trailing end of said chassis for attachment of a suitable cable employed to withdraw said chassis and launcher tube assembly from said conduit. In a first alternative embodiment (not shown), a single attachment point is provided at the trailing end of said 5 chassis for attachment of the end of a stiffly flexible rod employed to push said chassis and launcher tube assembly into said conduit and to withdraw it from said conduit. In a second alternative embodiment (not shown), a single attachment point is provided at the trailing end of said chassis for attachment to a suitable remotely powered and controlled tractor employed 10 to push said chassis and launcher tube assembly into said conduit and to withdraw it from said conduit. With additional reference to Figure 7, in operation, with said chassis and launcher tube assembly out of said conduit, a contact rail assembly 43 of suitable height is installed on said launcher tube. Said 15 displacement unit is powered to displace said inflatable mandrel from said launcher tube and, if necessary, said quick release pin is removed to detach said inflatable mandrel from said displacement unit. Repair pre-form 7 is impregnated with said settable resin on or off said inflatable mandrel (as described in relation to Figure 3), said inflatable mandrel is reconnected 20 to said displacement unit (if previously disconnected) and said displacement unit is powered to draw said inflatable mandrel carrying said impregnated repair pre-form into said launcher tube. Deflector 58 is deployed to its operational position and, if appropriate, its radial orientation is adjusted. A closed circuit television camera is positioned in 25 said main immediately beyond the opening of lateral or service connection 28 74 requiring said junction repair and orientated to view said opening, a typical line of sight being shown as 75 in Figure 7. Said chassis and launcher tube assembly is then winched or propelled into said main until said deflector is adjacent said lateral or service connection. Said chassis 5 and launcher tube assembly is jacked by said jacking means to bring said contact rails into firm contact with the inner surfaces of said main, thereby locking said chassis and launcher tube assembly securely in place in said main. If necessary, the radial orientation of said deflector is adjusted to bring the path it defines into register with the opening of said lateral or 10 service connection. Said displacement unit is then powered to displace said inflatable mandrel carrying said settable resin-impregnated repair pre form from said launcher tube and via said deflector into said lateral or service connection, said mandrel and flexible link 67 flexing appropriately to accommodate said displacement. The progress of said inflatable 15 mandrel and repair pre-form into said lateral or service connection is monitored using said closed-circuit television camera, if necessary said deflector being lowered to its said displaced-out position so as to not impede the view of said camera. In the preferred embodiment, said inflatable mandrel is made sufficiently long to support and install a 20 junction zone repair of a length 50 centimetres. In an alternative embodiment (not shown), where it is required to limit the length of a displacement to be effected by said displacement unit, a disc is provided on the free end of said ram of said displacement unit, being slightly smaller in diameter than the internal diameter of said launcher tube and 25 contacting stops provided in the wall of said launcher tube in appropriate 29 positions. In alternative embodiments, said inflatable mandrel is made to support a junction zone repair of a length of up to two metres. When said inflatable mandrel and said repair pre-form are correctly located in said lateral or service connection, fluid at a suitable pressure is supplied to said 5 mandrel via line 69, causing inflatable body 3 to expand, bringing repair pre-form 7 into intimate contact with the inner surfaces of lateral or service connection 74. As sizing sleeve 21 does not extend to the trailing end of said inflatable body, said inflatable body is able to expand to a greater degree in the transitional zone 76 at the junction of said main with 10 said lateral or service connection, thereby urging said repair pre-form into intimate contact with at least part of said transitional zone. In an alternative embodiment (not shown) for the same purpose, said inflatable body is suitably pleated at its trailing end to encourage its over-inflation. In another alternative embodiment (not shown) for the same purpose, the 15 trailing end of said repair preform is made thinner and more elastic and, if appropriate, with suitable pleating. Said inflatable mandrel is maintained in its inflated state until said settable resin has cured. Following curing of said settable resin, said deflector is restored to its operational position and said displacement unit is powered to withdraw said inflatable mandrel 20 from said lateral or service connection and via said deflector into said launcher tube. During withdrawal of said inflatable mandrel from said lateral or service connection, said release shroud everts and peels away from said cured repair to ensure a reliable release. Said chassis and launcher tube assembly is then withdrawn from said main, trailing end 25 first, using said cable, flexible rod or tractor and said chassis and launcher 30 tube assembly is prepared for the next junction zone repair. The end of said cured repair extending into said main is trimmed off flush using a suitable remotely powered and controlled tool. In an alternative embodiment (not shown), the contact surfaces of 5 said deflector and said launcher tube are coated with a suitable non-stick compound, including Teflon, a sprayed-on, drying Teflon release compound or a sprayed-on, drying silicone release compound. In another alternative embodiment (not shown), said deflector incorporates a plurality of transversely-arranged rollers to minimise friction and adhesion during 10 passage over it of said settable resin-impregnated repair pre-form. In another alternative embodiment (not shown), said deflector is made with said transversely-arranged rollers and with an endless belt running over said rollers to minimise friction and adhesion in the manner described. Said deflector is made to be readily removed and replaced and in different 15 configurations to accommodate the displacement of said inflatable mandrel into a lateral or service connection meeting said main at a 30 degree, 45 degree or 90 degree junction. Said inflatable mandrel is optionally used by itself for short length repairs in conduits. Said chassis has sufficient space beneath it to allow its 20 operation in a live (flowing) main without causing an appreciable obstruction. To accelerate curing of said settable resin, said inflatable mandrel is optionally inflated by filling it with hot water at a suitable pressure. In another embodiment for the same purpose, said inflatable mandrel is 25 inflated by a flow of steam at a suitable pressure, a calibrated leak being 31 provided in the leading end of said mandrel to permit the maintenance of a continuing flow. In another embodiment for the same purpose, inflatable body 3 of said inflatable mandrel is provided with suitable resistance elements which are supplied with electric current during the process of 5 curing of said settable resin. In another embodiment for the same purpose, said repair preform is provided with suitable resistance elements which are supplied with electric current during the process of curing of said settable resin. In another embodiment for the same purpose, said repair pre-form is impregnated with a radiation-curing resin the setting of which is 10 accelerated by irradiation with ultra-violet light. In an alternative embodiment (not shown), a mechanical latch joins flexible link 67 to said displacement unit, said latch being remotely operated by a suitable actuator to disconnect said displacement unit from said inflatable mandrel. Following inflation of said inflatable mandrel in 15 said lateral or service connection and prior to curing of said settable resin, said latch is operated and said chassis and launcher tube assembly is withdrawn from said main leaving said inflated mandrel in place in said lateral or service connection. Line 69 supplying said inflation medium to said inflatable mandrel continues to supply said medium and is permitted 20 to pay out through fairlead 70 during said withdrawal. Following removal of said chassis and launcher tube assembly from said main and during said process of curing of said settable resin, line 69 is optionally left connected to a source of suitable inflation medium. As appropriate, this need be only a small air bottle. 25 In a first embodiment, said settable resins are formulated to 32 provide a reasonable safe working time for an intended repair and to cure at ambient temperature. In alternative embodiments, suitable settable resins are employed in which curing is accelerated by heat or light. Where light is used to accelerate the setting of said settable resin, said sleeve of 5 said inflatable mandrel, said non-elastic sizing sleeve and said release shroud must be made suitably transparent. Said settable resins used with said invention optionally take the form of epoxy resins, polyester resins, vinyl ester resins, silicate-based resins or polyurethane resins. In an alternative embodiment (not shown), a short sleeve is 10 provided for installation in transitional zone 76 (as depicted in Figure 7) for the purpose of reinforcing it. Said short sleeve is installed either separately or simultaneously with the installation of said repair preform. Said short sleeve takes the form of a short cylindrical part to one end of which is fixed a radially-projecting flange of suitable width. Depending 15 upon the geometry of said transitional zone, the plane of said flange is positioned at a suitable angle to the longitudinal axis of said cylindrical part. For example, if said transitional zone is the entry to a service connection leading off at 45 degrees, the plane of said flange is positioned at an angle of 45 degrees to the longitudinal axis of said cylindrical part, 20 and so on. Said cylindrical part and said flange are built on a framework of thin, elastic metal wire. Said framework takes the form of a single length of wire laid up in two layers in opposed spiral arrangement, said wires extending fully along said cylindrical part and substantially into said flange. Said wire framework is arranged such that said cylindrical part has 25 a tendency to expand to a diameter greater than the internal diameter of a 33 service connection into which it is to be installed. Said wire framework is covered by a soft, loosely woven scrim material which also encloses a plurality of closely-spaced, axially-arranged reinforcement strips of woven fibreglass or similar material, said reinforcement strips passing radially 5 through said flange. Prior to its positioning in said transitional zone, said sleeve is impregnated with a suitable settable resin and placed in correct orientation on a suitable installation mandrel. Said installation mandrel is made with a fixed first part on which said flange is located by a plurality of suitable thin, sharp pins penetrating it, and a rotationally displaceable 10 second part to which said cylindrical part is located by a plurality of pivoting pins engaging it. Rotation of said second part in relation to said first part causes said cylindrical part of said sleeve to contract to a diameter smaller than that of the service connection into which it is to be installed. Said installation mandrel and said sleeve are then offered up to 15 said service connection until said sleeve is fully in place with said flange abutting said transitional zone. Said installation mandrel second part is then rotated in the opposite sense in relation to said first part, causing said pivoting pins of said second part to disengage from said cylindrical part and lie flat. Thus released, said cylindrical part is rotationally displaced in 20 relation to said flange by the elastic urging of said wire frame, thereby resuming its natural larger diameter and bringing it into intimate contact with the inner surfaces of the entry part of said service connection. Said repair preform is then installed over said sleeve in the manner described. In an alternative embodiment (not shown), the installation of said sleeve is 25 separately completed using a simple inflatable mandrel of suitable shape.

34 In another alternative embodiment (not shown), said wire frame is replaced with a light frame made by injection moulding from a suitable polymer material, said frame performing the same function. In addition to a vehicle and closed-circuit television equipment for 5 surveying, the present invention requires only a winch and compressed air source for its operation. Resin measurement, mixing and impregnation means are simple. The apparatus described is light and compact and can be operated reliably by one or two personnel with minimal training and minimal 10 support equipment. Said inflatable mandrel is fully flexible and carrying said impregnated pre-form, can be substantially smaller in diameter than a conduit to be repaired. It is thus able to readily negotiate the sharp changes in direction and cross-sectional area which may occur in conduits of relatively smaller diameter. The action of said release shroud ensures 15 that the apparatus may be reliably removed from a conduit upon completion of a repair. The capital and operating costs of the apparatus are low. Most importantly, the system of the present invention provides high productivity and cost-effective operation by permitting junction 20 zone repairs to be performed quickly and efficiently with minimal set-up time.

Claims

1. Apparatus for the in-situ repair of junction zones in conduits comprising an inflatable mandrel upon which is carried a repair pre-form impregnated with a settable resin; a launcher tube 5 supported on a chassis; actuator and jacking means to raise and lower said chassis and launcher tube assembly and lock it into place in a conduit; a displacement unit to displace said inflatable mandrel and said repair pre-form from said launcher tube; deflector means pivotally supported from the end of said 10 chassis to guide said inflatable mandrel and repair pre-form from said launcher tube into a lateral or service connection requiring a junction repair; actuator and displacement means to rotationally displace said deflector means; actuator and displacement means to deploy said deflector means into or out 15 of their operational position; wheels upon which said chassis and launcher tube assembly is rollingly supported; towing means to draw said chassis and launcher tube assembly on said wheels into or from a main conduit; electrical cables and fluid supply lines to supply electricity and pressurised fluid to said 20 displacement unit and said actuator and displacement means; and closed-circuit television equipment for positional observations.

2. The apparatus of Claim I in which said inflatable mandrel is designed for the repair of conduits in the diameter range 50 to 25 150 millimetres. 36

3. The apparatus of Claim 1 in which said inflatable mandrel comprises end fittings incorporating inflation air connection fittings and thrust connection means; an inflatable body the ends of an are sealingly bonded to shanks of said end fittings; a 5 replaceable release shroud extending axially for more than the full length of said inflatable body; multiple bridles attached to the leading said end fitting and detachably fixed to the leading end of said repair pre-form; and an internally positioned, anti elongation cable. 10 4. The apparatus of Claim 3 in which said inflatable body is made from a suitable elastic polymer material and is capable of inflation to 300 per cent of its deflated diameter.

5. The apparatus of Claim 3 in which said release shroud is made in tubular form from a light, thin, flexible sheet polymer 15 material and has an inflated diameter equal to or slightly less than that of the finished internal diameter of the repair to be effected.

6. The apparatus of Claim 3 in which said release shroud is made with a thickness in the range 0.15 to 1.0 millimetre and able to 20 tolerate an elastic extension of 20 per cent in the approximate temperature range 5* C to 400 C.

7. The apparatus of Claim 3 in which said release shroud is made from a material to which said settable resin adheres only weakly. 25 8. The apparatus of Claim 3 in which said release shroud is 37 optionally treated with a suitable release agent.

9. The apparatus of Claim 3 in which the ends of said release shroud are optionally secured to said end fittings by a clamping band or frangible tape or tie means. 5 10. The apparatus of Claims I and 3 in which said repair pre-form is provided with positive location on said release shroud by a peelable adhesive or by self-adhesive patches of the hooked part of the Velcro@ attachment system being attached to said release shroud, the hooked elements engaging the inner fibrous surface 10 of said repair pre-form.

11. The apparatus of Claim 3 in which said anti-elongation cable is attached to the inner parts of said end fittings and has slack in the range 100 to 150 millimetres for each metre of length of said inflatable mandrel. 15 12. The apparatus of Claim 3 in which said anti-elongation cable is made from chain or multi-strand metal cable.

13. The apparatus of Claim 3 in which said inflatable body has a thickness in the range 2.0 to 8.0 millimetres and a normal maximum length of three metres. 20 14. The apparatus of Claim 3 in which said inflatable body is inflated to a pressure in the range 100 to 250 kPa.

15. The apparatus of Claim I in which said repair pre-form is made with thicknesses according to the following table: 25 38 CONDUIT DIAMETER (MM) PRE-FORM THICKNESS (MM)

50-100 2-3

100-200 2-5

200-300 3-6 5 16. The apparatus of Claim 1 in which said repair pre-form for making repairs in conduits up to 150 millimetres in diameter is made from a single thickness of knitted pile material having a thickness in the range 2 to 5 millimetres and tolerating a circumferential and axial elastic extension of not les than 25 per 10 cent. 17. The apparatus of Claim 1 in which said repair pre-form for making repairs in conduits up to 150 millimetres in diameter is made from a single thickness of knitted pile material having a thickness in the range 2 to 5 millimetres and tolerating a 15 circumferential and axial elastic extension in the range 20 to 40 per cent. 18. The apparatus of Claim 1 in which said repair pre-form for making repairs in conduits up to 150 millimetres in diameter is made in tubular form and is impregnated with said settable resin 20 on said release shroud prior to or following its positioning on said inflatable mandrel. 19. The apparatus of Claim I in which said repair pre-form for making repairs in conduits larger than 150 millimetres in diameter is made with a thickness in the range 5 to 10 25 millimetres in flat sheet form; is separately impregnated with 39 said settable resin in its flat state, wrapped around said release shroud which has been previously positioned on said inflatable mandrel, and secured in place in wrapped form by suitable frangible ties, elastic bands or the like. 5 20. The apparatus of Claim 19 in which said repair pre-form optionally includes layers of knitted pile material, woven reinforcement material or needled felt fused, bonded or quilted together. 21. The apparatus of Claim 3 in which the ends of said inflatable 10 body are sealingly fixed to shanks of said end fittings by collars swaged over them. 22. The apparatus of Claim 3 in which, in an inflatable mandrel for repairing conduits in the diameter range 150 to 600 millimetres, said inflatable body is made from a thin, strong, flexible, 15 impervious, non-elastic sheet material of tubular form having a diameter up to 200 per cent of that of the shanks of said end fittings and is sealingly attached to said shanks by clamping bands, one or more circumferential folds being inserted into said material before installation of said clamping bands. 20 23. The apparatus of Claim 22 in which said inflatable body is fabricated from a suitable flat sheet material with sewn, fused or taped seams. 24. The apparatus of Claim 22 in which a non-elastic sizing sleeve is installed over said inflatable body to limit its inflational 25 expansion, the ends of said sizing sleeve being optionally left 40 unsecured or fixed to said end fittings by frangible fastenings. 25. The apparatus of Claim 24 in which said sizing sleeve is made from a strong, flexible, non-elastic fabric and covers the leading end of said inflatable body and between 50 and 80 per cent of 5 its length, leaving 50 to 20 per cent at the trailing end of said inflatable body uncovered, said uncovered part being free to balloon when inflated. 26. The apparatus of Claims 3 and 25 in which said inflatable body is suitably pleated at its trailing end to encourage over-inflation of 10 said inflatable body to better urge said repair pre-form into contact with the flared transitional zone between said main conduit and said lateral or service connection. 27. The apparatus of Claims 3 and 25 in which the trailing end of said repair preform is made thinner and more elastic and, 15 optionally, with suitable pleating to permit it to better conform to the flared transitional zone between said main conduit and said lateral or service connection. 28. The apparatus of any of Claims 3, 11, 12 and 22 in which an anti-elongation cable is optionally provided in a said inflatable 20 mandrel having a non-elastic inflatable body. 29. The apparatus of Claim 22 in which said inflatable body is inflated with pressures ranging from 80 kPa at 150 millimetres conduit diameter to 40 kPa at 600 millimetres conduit diameter. 30. The apparatus of Claim I in which said chassis comprises an 25 elongated box structure having apertures in its lower panels 41 through which project wheels and jacking means; said wheels and said jacking means being, respectively, rotationally and pivotally supported on common shafts passing between panels of said chassis; and a saddle fixed to its upper part in which said 5 launcher tube is supported. 31. The apparatus of Claim 1 in which said wheels are rotationally supported on separate fixed shafts. 32. The apparatus of Claim I in which said wheels are rotationally supported on stub shafts provided on the free ends of wheel 10 supporting arms pivotally supported from said chassis, said wheels being simultaneously displaceable, upwardly or downwardly, by manually-operated or power-operated displacement means to adjust the height of said chassis and launcher tube assembly. 15 33. The apparatus of Claim I in which said jacking means take the form of arms pivotally supported on horizontal or angled shafts and which move, respectively, in vertical or oblique planes. 34. The apparatus of Claim 1 in which said jacking arms are pivotally displaceable into more or less horizontal positions, 20 permitting the weight of said chassis and launcher tube assembly to be carried upon said wheels. 35. The apparatus of Claim 33 in which the lower ends of said jacking arms are formed into pads, the lower surfaces of which are curved to facilitate contact with the inner surfaces of a main 25 conduit at a variety of angles, said lower surfaces being made 42 hard and serrated or coated with hard asperities. 36. The apparatus of Claim 33 in which said jacking arms are simultaneously deployed by a pivoted actuator applying force to an actuator arm connected to said jacking arms by jacking arm 5 actuator rods, rotation of said actuator arm causing rotational displacement of said jacking arms and thereby bringing their lower ends into contact the wall surfaces of said main conduit, further rotational displacement of said jacking arms causing bodily lifting of said chassis and launcher tube assembly. 10 37. The apparatus of Claim 1 in which said jacking means take the form of rams directed downwardly, either vertically or obliquely, said rams optionally being either simple or telescopic and taking the form of ball-screw of fluid pressure actuators. 38. The apparatus of Claim I in which said jacking means take the 15 form of lazy tongs-type struts. 39. The apparatus of Claims 37 or 38 in which contact pads on the ends of said rams are free to align themselves with the curved internal surfaces of a main conduit and are either made hard and serrated or coated with hard asperities. 20 40. The apparatus of Claims 1 and 30 in which said launcher tube is retained in place on said saddle by fastenings passing through complementary flanges provided on both. 41. The apparatus of Claims 1 and 30 in which said launcher tube is retained in place on said saddle by clamping bands passing 25 around it, rotational adjustment of the position of said launcher 43 tube being made by loosening said clamping bands. 42. The apparatus of Claim 1 in which said chassis and launcher tube assembly are locked into position in a main conduit by their being raised by said jacking means to bring contact rails 5 fixed to the upper surface of said launcher tube into contact with the upper surface of said main conduit. 43. The apparatus of Claim 42 in which the upper edges of said contact rails are made hard and serrated or coated with hard asperities to provide better fictional engagement with said 10 upper surfaces of said main conduit. 44. The apparatus of Claim 42 in which said contact rails are made in a range of heights to suit main conduits of differing diameters and are fixed to said launcher tube by quick-release fastenings. 45. The apparatus of Claims I and 42 in which said contact rails are 15 fixed to a suitable beam and suitable jacking means are employed to raise said beam to bring said contact rails into contact with the upper surface of a main conduit. 46. The apparatus of Claim I in which said chassis and launcher tube assembly is raised by means of inflatable jacking pads 20 incorporated into the lower part of said chassis, the said arrangement optionally being used in conjunction with fixed or separately displaceable contact rails. 47. The apparatus of Claims I and 42 in which said contact rails are deleted and jacking means of the types described are employed 25 to contact the upper surface of a main conduit. 44 48. The apparatus of Claim I in which said deflector means are pivotally supported from the leading end of said launcher tube together with said actuator which deploys said deflector means into or out of their operating position, the radial orientation of 5 the axis of said deflector means being adjusted by loosening attachment provisions of said launcher tube and rotating said launcher tube appropriately. 49. The apparatus of Claim I in which said deflector means are pivotally supported from a collar rotationally supported at the 10 leading end of said launcher tube together with said actuator which deploys said deflector means into or out of their operating position, the radial orientation of the axis of said deflector means being adjusted by rotation of said collar. 50. The apparatus of Claim 49 in which said collar is provided with 15 a circular or part-circular rack which is engaged by a suitable pinion driven by a suitable actuator, operation of said actuator causing rotational displacement of said collar. 51. The apparatus of Claim 49 in which said collar is provided with a deep cylindrical flange having a helical slot extending 20 throughout its axial length, a peg fixed to a rod slidingly supported in bearings slidingly engages said slot, axial displacement of said rod by means of a suitable actuator causing rotational displacement of said collar. 52. The apparatus of Claim 49 in which a push-pull rod is pivotally 25 connected at a tangent to said collar, displacement of said push- 45 pull rod by a suitable actuator causing rotational displacement of said collar. 53. The apparatus of Claim I in which lever arms fixed the sides of said deflector means extend towards the free end of said 5 deflector means, said deflector means being deployed into their said operational position by tension applied to said lever arm free ends via rods or cables connected to a suitable actuator. 54. The apparatus of Claim I in which said deflector means are supported in their operational position by one or more over 10 centre links, said over-centre links being broken by a small force applied via a Bowden cable or electric solenoid to permit said deflector means to be displaced out of their operational position. 55. The apparatus of Claim I in which said deflector means are 15 coated on their working surfaces with a suitable non-stick compound. 56. The apparatus of Claim 1 in which said deflector means incorporate a plurality of transversely-arranged rollers to minimise friction and adhesion during operation. 20 57. The apparatus of Claim I in which said deflector means incorporate a plurality of transversely-arranged rollers over which an endless belt runs to minimise friction and adhesion during operation. 58. The apparatus of Claim I in which said deflector means are 25 readily replaced by others of differing configurations to suit 30, 46 45 and 90 degree junctions. 59. The apparatus of Claim I in which said displacement unit is supported on webs or brackets inside the trailing end of said launcher tube, is telescopic in action and actuated by 5 electrically-operated ball screw or fluid pressure. 60. The apparatus of Claim 1 in which the free end of the ram of said displacement unit is connected to the trailing said end fitting of said inflatable mandrel by means of a stiffly flexible link, said link being sufficiently long and providing sufficient 10 flexibility to accommodate the displacement of said inflatable mandrel into 90 degree junctions. 61. The apparatus of Claim I in which said displacement unit is made readily replaceable with another of greater or lesser displacement. 15 62. The apparatus of Claim 60 in which the free end of said stiffly flexible link is connected to said inflatable mandrel end fitting by a plug and socket arrangement secured by a quick-release pin. 63. The apparatus of Claim 1 in which said displacement unit is 20 actuated to displace said inflatable mandrel from said launcher tube, in order to prevent chafing, lines to said inflatable mandrel being drawn through a fairlead during said displacement. 64. The apparatus of Claim I in which said inflatable mandrel carrying said repair pre-form is displaced by said displacement 25 unit from said launcher tube and deflected by said deflector 47 means into a lateral or service connection requiring a junction repair. 65. The apparatus of Claim 3 in which the displacement distance effected by said displacement unit is limited by a thick disc 5 installed on the free end of said displacement unit ram, said disc having a diameter slightly smaller than that of the internal diameter of said launcher tube and contacting stops installed in the wall of said launcher tube in appropriate positions. 66. The apparatus of Claim 1 in which two towing cables connect 10 the leading edge of said chassis to a tow bar, said tow bar being drawn by a single cable to position said chassis and launcher tube assembly within a main conduit, the space between said two towing cables being sufficient to permit said deflector means to be displaced out of their said operational position. 15 67. The apparatus of Claim 1 in which an attachment point is provided at the said trailing end of said chassis, said attachment point permitting the attachment of a cable, tractor or flexible pushrod; said cable being employed to withdraw said chassis and launcher tube assembly from a main conduit and said 20 tractor and pushrod being employed to propel said chassis and launcher tube assembly into or withdraw it from a said main conduit. 68. The apparatus of Claim I in which said actuator and displacement means are electrical, hydraulic or pneumatic in 25 operation and are either ball-screw or fluid pressure-operated 48 ram in terms of functionality. 69. The apparatus of Claim I in which a closed-circuit television camera is employed to view the leading end of said chassis and launcher tube assembly to verify positioning in relation to a 5 lateral or service connection requiring a junction repair and the proper operation and positioning of said deflector means. 70. The apparatus of Claim 1 in which curing of said settable resin is optionally accelerated by filling said inflatable mandrel with hot water at a suitable pressure. 10 71. The apparatus of Claim I in which curing of said settable resin is optionally accelerated by inflating said inflatable mandrel with a flow of steam at a suitable pressure, a calibrated leak being provided in the leading end of said mandrel to permit the maintenance of a continuing flow. 15 72. The apparatus of Claim I in which curing of said settable resin is optionally accelerated by providing said inflatable mandrel with suitable resistance elements which are supplied with electric current, and thereby heated, during the process of curing of said settable resin. 20 73. The apparatus of Claim 1 in which curing of said settable resin is optionally accelerated by providing said repair preform with suitable resistance elements which are supplied with electric current, and thereby heated, during the process of curing of said settable resin. 25 74. The apparatus of Claim I in which said repair pre-form is 49 impregnated with a radiation-curing resin the setting of which is accelerated by irradiation with ultra-violet light. 75. Apparatus according to Claim 74 in which said non-elastic sizing sleeve and said release shroud are made suitably transparent. 5 76. Apparatus according to Claim 1 in which said settable resin takes the form of epoxy resins, polyester resins, vinyl ester resins, silicate-based resins or polyurethane resins. 77. Apparatus of any of Claims 1, 60 and 62 in which a mechanical latch joins said stiffly flexible link to said inflatable mandrel, said 10 latch being remotely operable by a suitable actuator to disconnect said displacement unit from said inflatable mandrel, thereby permitting said chassis and said launcher tube assembly to be withdrawn from a main conduit, leaving said inflated mandrel in place in said lateral or service connection. 15 78. Apparatus according to Claim 77 in which, as said chassis and launcher tube assembly is withdrawn from said main conduit, the line supplying said inflation medium to said inflatable mandrel continuing to supply said inflation medium while it is brought out to the next access point to said main conduit and connected to a 20 suitable source of inflation medium. 79. Apparatus according to Claim 78 in which said source of inflation medium takes the form of a small compressed gas bottle. 80. Apparatus according to Claim I in which a short sleeve or repair 25 pre-form is provided for the purpose of reinforcing said flared 50 transitional zone prior to installation of a junction repair; said short sleeve being optionally installed separately from or simultaneously with the installation of said normal repair preform and taking the form of a short cylindrical part to one end of which 5 is fixed a radially-projecting flange at an angle to suit the angle of entry into said main conduit of said lateral or service connection; said cylindrical part and said flange being built on a framework of thin, elastic metal wire laid up in two layers in opposed spiral arrangement, said wires extending fully along said cylindrical 10 part and substantially into said flange; said wire framework being arranged such that said cylindrical part has a tendency to elastically expand to a diameter greater than the internal diameter of said lateral or service connection; said wire framework being covered by a soft, loosely woven scrim material which also 15 encloses a plurality of closely-spaced, axially-arranged reinforcement strips of woven fibreglass or similar material, said reinforcement strips passing radially out through said flange; said sleeve, prior to its positioning in said transitional zone, being impregnated with a suitable settable resin and placed in correct 20 orientation on a suitable installation mandrel; said installation mandrel being made with a fixed first part on which said flange is located by a plurality of suitable thin, sharp pins penetrating it, and a rotationally displaceable second part to which said cylindrical part is located by a plurality of pivoting pins engaging 25 it, rotation of said second part in one sense in relation to said first 51 part causing said cylindrical part of said sleeve to contract to a diameter smaller than that of said lateral or service connection; said installation mandrel and said settable resin-impregnated sleeve being offered up to said service connection until said 5 sleeve is fully in place with said flange abutting said transitional zone; said installation mandrel second part then being rotated in the opposite sense in relation to said first part, causing said pivoting pins of said second part to disengage from said cylindrical part and lie flat, said cylindrical part, thus released, 10 being rotationally displaced in relation to said flange by the elastic urging of said wire frame, thereby resuming its natural larger diameter and bringing it into intimate contact with the inner surfaces of the entry part of said lateral or service connection; a said repair preform then being installed over said 15 sleeve in the manner previously described. 81. Apparatus according to Claim 80 in which said sleeve is separately installed using a simple inflatable mandrel of suitable shape. 82. Apparatus according to Claim 80 in which said wire frame is 20 replaced with a frame of light, elastic elements made by injection moulding from a suitable polymer material. 83. A method for the in-situ repair of junction zones in conduits comprising: (a) Fitting of appropriate contact rails to said launcher tube; 25 (b) Impregnation of said repair pre-form with said settable 52 resin; (c) Reconnection of said inflatable mandrel to said displacement unit (if previously disconnected); (d) Operation of said displacement unit to draw said 5 inflatable mandrel carrying said impregnated repair pre form into said launcher tube; (e) Deployment of said deflector to its operational position; (f) Positioning of a closed-circuit television camera in said main conduit immediately beyond the opening of said 10 lateral or service connection and orientated to view said opening and said deflector; (g) Winching by cable or propelling by tractor or flexible rod of said chassis and launcher tube assembly into said main conduit until said deflector is adjacent said lateral or 15 service connection; (h) Jacking of said chassis and launcher tube assembly by said jacking means to bring said contact rails into firm contact with the inner surfaces of said main conduit, thereby locking said chassis and launcher tube assembly 20 securely in place in said main conduit; (i) Adjustment of the radial orientation of said deflector to bring the path it defines into register with the opening of said lateral or service connection; (j) Operation of said displacement unit to displace said 25 inflatable mandrel carrying said settable resin- 53 impregnated repair pre-form from said launcher tube and via said deflector into said lateral or service connection; (k) Monitoring of the progress of said inflatable mandrel and said repair pre-form into said lateral or service connection 5 using said closed-circuit television camera (if necessary said deflector being lowered to its said displaced-out position so as to not impede the view of said camera); (1) When said inflatable mandrel and said repair pre-form are correctly located in said lateral or service connection, 10 supplying fluid at a suitable pressure to said mandrel, causing said inflatable body to expand and bringing said repair pre-form into intimate contact with the inner surfaces of lateral or service connection, over-inflation of said trailing end of said inflatable body urging said repair 15 pre-form into intimate contact with at least part of said flared transitional zone; (m)Maintaining said inflatable body in fully inflated form while said settable resin cures; (n) Following curing of said settable resin, deflation of said 20 inflatable mandrel, restoring of said deflector to its operational position and operation of said displacement unit to withdraw said deflated mandrel from said lateral or service connection via said deflector and into said launcher tube, said release shroud everting and peeling 25 away from said cured repair during withdrawal of said 54 mandrel; (o) Withdrawal said chassis and launcher tube assembly from said main conduit, trailing end first, using said cable, flexible rod or tractor; 5 (p) Using a suitable remotely powered and controlled tool, trimming off flush the end part of said cured repair extending into said main conduit. 84. The method of Claim 83 in which said repair pre-form is made in tubular form and is impregnated with said settable resin on 10 said release shroud prior to or following its positioning on said inflatable mandrel. 85. The method of Claim 83 in which said repair pre-form is made in flat sheet form and separately impregnated with said settable resin in its flat state, wrapped around said release shroud which 15 has been previously positioned on said inflatable mandrel, and secured in place in wrapped form by suitable frangible ties, elastic bands or the like. 20 25 55