It has become environmentally and politically an imperative to try to prevent leakage of essential commodities such as water. Water is often transported underground in mains, some of which owing to age, subsidence or the like, leak. It is expensive to excavate and relay such a main, so systems have been developed for re-lining them in situ.

However, mains often have branch pipes or ferrules feeding a water supply to say a dwelling. Lining the pipe with a liner, which is essentially a tube of material deployed in the main, necessarily cuts off flow connection between the main and the branch pipe. If a flow connection is established, the water can and does hitherto seep "behind"the liner, that is between it and the main, leading again to leakage, and to loss of flow to the dwelling.

It is an object of the invention to seek to mitigate this disadvantage.

According to a first aspect of the invention there is provided a system for securing a liner in a main for flowable material adjacent a branch pipe of the main whilst providing flow connection between the main and the branch pipe, comprising means to locate the position of the branch pipe when the liner is installed, means to form an orifice through the liner to provide said flow connection, and a device for sealing the boundary of the through orifice against leakage of flowable material between the liner and the main.

The locating means may comprise an electronic means. This is a relatively simple yet effective means, particularly when the electronic means may comprise a transponder located in the branch pipe.

The transponder may be inserted in the branch pipe from interiorly of the main. This can provide an efficient system.

The locating means may comprise an emitter of ultrasound and a detector of ultrasound. This is an effective alternative system.

The detector may comprise a mobile robot device adapted for travelling along the main.

The locating means may comprise means to apply an electromagnetic signal to the branch pipe, and a mobile robot device adapted for travelling along the main and to detect the signal.

The system may include a robot device for forming the through orifice in the liner at a branch pipe.

The electronic means may comprise a flexible device which flexes on insertion in the branch pipe for retention therein, the amount of flexure providing details of parameters of the branch pipe.

According to a second aspect of the invention there is provided a device for securing an edge of an orifice through the material of a liner of a main at a branch pipe, comprising a body which is adapted for sealing the edge against leakage between the liner and main, and for securing the device in the main.

The body may comprise an annular part incorporating seal means for sealing the edge. This is a relatively simple construction.

The sealing means may also be adapted for securing the device in position.

The sealing means may comprise an annular layer of butyl adhesive, or an adhesive tape.

There may be means to accommodate pressure of material within the main, particularly the accommodating means may comprise bellows means, for example comprising a resilient body or a cellular structure.

There may also be means for mounting the device in a branch pipe.

According to a third aspect of the invention there is provided a main with a branch pipe, whenever lined using a system as hereinbefore defined or incorporating a device as hereinbefore defined.

A system and device embodying the invention are hereinafter described, by way of example with reference to the accompanying drawings.

Fig. 1 is a schematic side elevational view of a main with a branch pipe or ferrule; Fig. 2 is a schematic side elevational view of a liner with a through orifice therethrough adjacent an entry to the ferrule; Figs. 3 and 4 show steps in insertion of a device according to the invention through an orifice in the liner; Figs. 5 to 8 show views of a second embodiment of device embodying the invention, Fig. 6 being a plan view in the direction of arrow"X"of the device shown in Fig. 5; Fig. 9 is a modification of the embodiment of Figs. 5 to 8; and Figs. 10 to 37C show schematically various other embodiments of securing a liner in a host pipe.

Referring to the drawings there is shown a system 1 for securing a liner 2 in a main 3 or host pipe for conveying flowable material adjacent a branch pipe or ferrule 4 of the main 3 whilst providing flow connection between the main 3 and the branch pipe 4, comprising means 5 to locate the position of the branch pipe 4 when the liner 2 is installed, means 6 to form an orifice 7 through the liner 2 to provide said flow connection, and a device 8,9,10 for sealing the boundary of the through orifice 7 against leakage of flowable material between the liner 2 and the main 3.

The locating device 5 in Fig. 1 is an electronic device such as a "smart"card which is an electronic means which can be inserted in the bore 11 of the ferrule by a robot device (not shown) which can travel along the main 3. The device 5 is inserted in the ferrule 4 before the liner 2 is inserted. When so inserted, the robot via a detection means can locate the ferrule via the device, which acts as a"homing"device, and can then cut the orifice 7 through the liner 2 by a suitable cutting tool comprising the means to form the orifice 6. The device 5 not only allows detection of where each ferrule in a main 3 is, but can provide ferrule parameters, such as ferrule bore size for example, the signal given by the device being proportional to the flexure thereof. The cutting tool in one embodiment is heated by the robot to about 200°C.

At this temperature the cutter displaces liner material and passes smoothly through the thickness of the liner 2, which is made of polyethylene, with a constant speed and with constant force. The liner 2 is not charred, and there is no smoking during cutting. After the cutting operation, the cut edge of the hole re-hardens when the (heated) cutting tool 6 is withdrawn, to provide access to the bore of the ferrule 4.

As shown in Fig. 2, there is a gap"a"between the installed liner 2 and the main 3 which is taken up when the liner is being pressurised by mains water.

In order to prevent seepage or passage of water behind the liner, that is between the liner and the main, a device 8 like that of Figs. 3 and 4 may be used. The device 8 has a body with an annular part 12 which is dished and which includes an annular ring 13 of sealant or adhesive such as butyl or a tape (for example a PTFE tape) and a hollow cylindrical part 14 which is inserted in the bore 11 of the ferrule 4 (Fig. 4).

The sealant 13 as shown seals the edge of the material of the liner 2 which defines a boundary of the hole 7, and seals to the main, when the device is forced into position by the robot.

In Figs. 5 to 8, the device 9 is a gasket-like device having a dished body 15 with an annular ring of sealant or adhesive 16 and a bellows type component which is resilient metal or plastic, or could be a closed foam cellular annular construction with an annular ring 18 of adhesive for sealing to the main adjacent the ferrule, which has been located as before.

The body part 15 and bellows 17 are bonded together at'b'to provide a composite unit. The bellows 17 in use allows the liner 2 to expand towards the wall of the main 3, under pressure of water in the main.

Fig. 9 shows a modification of Figs. 5 to 8 in which there is additional mounting means of the device 10 in the form of spring fingers 19 which can be serrated at 20 for insertion in the bore of the ferrule; the serrations 20 if present allow for a firm grip and hence mounting in the ferrule 4, and thus this positive engagement assists in maintaining the sealant 16,18 bonded to the bore of the mains and to the edge of the orifice 7 in the liner.

Referring now to Figs. 10 to 13, there are shown further embodiments of device for sealing the boundary of the through orifice.

Fig. 10 shows a device 21 in the form of a bellows like device made of resilient material and having a channel 22 having lips or limbs 23 which are sprung into place over the cut edge defining the hole 7 through the liner 2. A relatively rigid locking ring 24 of say metal and of wedge-configuration in cross-section is then forced into an annular seating 25 for it. The device 21 is then locked into the liner 2 by the lateral force provided by the wedge action of the locking ring 24. The device 21 has an adhesive sealant 26 such as a butyl adhesive layer which is held in place by the device at the ferrule to obviate leakage into the thread of the ferrule, and behind the liner 2.

In Fig. 11, the device 27 has a bellows membrane 28 with a relatively rigid ring 29 for strength, and an upper (as viewed) adhesive layer 30 such as butyl adhesive on an upper (as viewed) part of the bellows and on the lower part a connector 31 for engaging the liner 2 adjacent its cut edge by a barb 32 or barbs which is/are heated on installation. There is also an additional seal 33 formed by spaced rings of annular cutters which receive between them a conventional'0'ring seal or sealant 34. A resilient member 35 spans between the upper part of the device and the connector 31 to assist in preventing butyl sealant detaching from the host pipe under vacuum conditions. There is a sealant at 36 too, where the components are bonded together. As shown in the modification of Fig. 12, the connector 31 has a resilient member 37 to provide a continuous pressure on the sealant 34.

Figs. 13 to 15 show further embodiments in the form of respective variations on a post-liner gasket, which has a peripheral flange 38 which could be, like the gasketperse, of polyethylene, which is held in place on the liner adjacent the cut through hole 7 by a heatable, suitably metal, insert which is annular so that in use it surrounds the hole 7. The insert 39 is heated and forced through the gasket 38 into the liner 2 which action causes fusion welding of the liner and gasket to take place, thus providing a leak-tight joint. There could be serrations or barbs on the insert 39 to ensure a firmer grip within the flange 38 and liner 2, and the serration or barbs could be of such a design that by oscillating the heated insert 3 during insertion mixing of the molten material occurs, thus enhancing the welded joint.

In Figs. 14 and 15, the insert 39 has serrations 110 and an annular ring seal 41 comprising a channel containing adhesive such as butyl or a conventional elastomeric seal. There is relative movement between the liner 2 and insert 39 on cooling, which causes liner 2 material to compress the ring seal 41, providing a leak-tight connection.

Figs. 16A to 16C show a further embodiment, and Fig. 17 an enlarged view of a development thereof. In this embodiment a heatable expansion collet is positioned interiorly of the liner 2, Fig.

16A. When the collet is heated, and expanded under pressure, Fig.

16B, the polyethylene liner is softened and pushed out to the wall of the host pipe 3, thus sandwiching the adhesive between the liner and the host pipe, resulting in a permanently tight fit in the pipe 3 once the liner cools (Fig. 16C).

As the polyethylene is heated and softened it shows no propensity to pull away from the pipe, so there are no forces on the adhesive seal which thus maintains its integrity, and this is also the case in the locality of the ferrule 4. At the ferrule a pressure assisted membrane 43 is applied after the liner 2 is position as in Fig. 16C. The membrane 43 can be applied by a robot from within the pipe 3 and liner 2 combination. This maintains cleanliness of the system.

A similar result is shown in Figs. 18 and 19 where an annular support ring 44 is supported mechanically by a support 44'which is resilient or sprung and is used to assist in maintaining the ring 44 and membrane 43 in place adjacent the bore of the ferrule.

Figs. 20 to 22 show an embodiment where a tension bush is used to assist in maintaining the membrane in place.

In Figs. 20 and 21 the tension bush 45 is a metal band with stepped ends so as to mate to form a circle, there being ratchet teeth 48 on the outer surface of the bush 45, there being a thin metal strip 46 the same width as the bush secured at one end as by welding to the bush 45 and having a finger or bent end 47 at the opposite end to engage the ratchet teeth. Once the bush 45 (which can have a relatively thin wall thickness) is expanded to the required diameter, the tooth 47 is engaged in the ratchet 48, which thus holds the bush 45 in position rather than relying on residual spring tension of the bush.

In Fig. 22, the bush 49 has ratchet teeth 50 at each end, the metal strip 51 in the form of a wide circlip having a tooth 52 at each end for engaging a respective ratchet 50. The bush 49 and gasket 43 are positioned in the liner adjacent the hole 7 therethrough under the ferrule by a robot and the metal strip is then positioned and opened out by the robot, the fingers 52 engaging in a respective ratchet to hold the assembly in position and effect a tight seal, as before.

Figs. 23 and 24 show an embodiment on which a support ring 53 for the membrane 43 is held in place by a pivotable circlip 54. Free ends or bent fingers 55 of the circlip are received in respective seats 56 of the support ring 55. The circlip being sprung is forced when in position, by a robot to be substantially perpendicular to the longitudinal axis of the liner 2, as shown schematically in Fig. 24.

The pivoting action forces the support ring 53 more firmly against the membrane 43 to ensure a tight seal. The outer surface of the circlip 54 could be serrated to prevent movement after installation.

Figs. 25 and 26 show embodiments where a resilient material 57 is interposed between the support ring 58 and membrane 43. This ensures that continuous pressure is maintained, so enhancing adhesion and thus leak-tightness.

In Fig. 26, the resilient material has an enlarged section 59 which bears against the membrane. This also helps prevent the membrane seal 43 from detaching from the host pipe 3 during surge and/or vacuum conditions.

Figs. 27 to 29A show an embodiment where a disc 60 of adhesive such as butyl adhesive is applied over the inner surface of the ferrule 4 by a robot, either before or after the liner 2 is installed. The disc 60 comprises a plastic packing film 61, a layer of adhesive 62 and one or more thick rings 63 of adhesive. This disc 60 is essentially flat, as shown in Fig. 27 before application by the robot. The disc 60 is deformed when it is forced into place by the robot, as shown in Fig.

28.

Figs. 29 and 29A show a disc 60 which is reinforced by a reinforcement 64 in the form of an annular ring of filament which provides a relatively high shear strength and allows for the deformed thickness of the disc and hence of the adhesive to be relatively large, which is good for smoothing out surface irregularities or filling in deformities such as pitting in cast iron host pipes.

In Figs. 30 and 30A the disc includes an 0-ring 65 which has a mechanical support 66.

Figs. 31 and 31 A and 32 and 32A show respectively a disc 67,68 including a bellows 69 and a resilient bush 70. Figs. 31 A and 32A showing this configuration after the disc is deformed and installed by the robot. Both the bellows 69 and the resilient bush 70 increase the pressure on the adhesive, which in all embodiments herein is a viscous sealant. The pressure of water in the host pipe flattens item 69', which can be strong sprung stainless steel, its large surface area greatly increasing the pressure on the viscous sealant.

In the embodiments described herein utilising discs which cover the ferrule, the viscous adhesive disc is ruptured from within the liner by the pressure of water, simultaneously opening up the bore of the ferrule to flow and"wrapping"the viscous adhesive round the ferrule threads and sealing them and the free edge of the liner while also being adhered firmly to the wall of the host pipe, ferrule and liner, so obviating leakage.

The means 5 for detecting the ferrule when a liner is in place can be an eddy current system.

Figs. 33A and 33B show a display on a screen of results obtained using a transducer to detect eddy currents from tests on a 4"used pipe.

Fig 33B clearly shows the location of the ferrule, which is of brass. Variations in the diameter of the liner did not effect the detection of the ferrule owing to separate directions of variation in the impedance plane. The transducer is operated at an optimum frequency in this case of 70kHz.

Figs. 34 and 34A show further embodiments of sealing at the ferrule 4. These utilise a piston 70 and cylinder 71 arrangement as an alternative to for example the bellows-like devices of previous embodiments. The piston and cylinder 70,71 each have lip seals 72 to facilitate relative movement between them. Either the piston 70 or the cylinder 71 can move to provide pressure on the membrane 43, and there may be a mechanical support for the piston/cylinder assembly, which with the alternative of Fig. 34A enable the two halves of the piston sealing assembly 73 to be fitted independently.

Figs. 35 and 35A show embodiments where a liner 2 is cut adjacent the ferrule 4 by a pre-installed"blunt"cutter 74 which is heated by induction and cuts out the hole in the liner as before. A lip seal 75 assists in enhancing leak-tightness, while in Fig. 35A a resilient ring 76 assists adhesion during vacuum conditions. The cutter can have barbs for assisting retention.

Fig. 36 shows an embodiment where a plug or bung 77 can be applied by a robot in the unlikely event of the membrane being found to have sprung a leak. The bung 77 is supported on the end in this case of the bellow 78, and there is a sealing ring 79 too.

It will be understood that where ferrules project beyond the inner surface of a host pipe it is important that their projecting ends do not damage the outer surface of the liner during installation. Moreover, the ferrule itself should not be moved/dislodged by the liner during installation. These matters can be addressed by chamfering the protruding end of the ferule using a robot mounted chamfering device. During this operation, any relative movement between the flat free end surface of the ferrule and the interior surface of the pipe adjacent the ferrule can be monitored, which would show if the ferrule is loose and should be replaced before the liner is installed.

The chamfering avoids damage to the liner during installation. Alternatively, a plurality of (say three) displacement transducers are attached to a device which incorporates a force ring. This is applied to the ferrule by a robot and a predetermined force is applied. If the average recorded transducer reading is less than a predetermined value, then the ferrule can be considered to be secure at its threaded joint in the host pipe.

Figs. 37A, B and C show steps in use of a modified gasket or disc 80, which includes a disc 81 of viscous sealant or adhesive such as butyl, a thin plastic film 82 thereover, an annular pad 83 suitably of resilient material and a plastic cover 84. The gasket 80 is applied over the ferrule 4 by the robot, the pad assisting in causing the viscous adhesive or sealant to follow the contour of the bore of the host pipe 3. The liner is then installed (Fig. 37B). A coupon 85 of the lining is then cut and removed by the robot, attached to a coupon 84a of the plastic cover 84. Subsequent pressure from water in the pipe bursts the thin plastic film 82 and at the same time folds it and the disc 80 of the viscous sealant into and to adhere to the bore of the ferrule, so that a leak-tight seal is made with the host pipe 3. The surface of the pad 83 also has a layer of viscous sealant so that it forms a leak-tight seal with the liner 2. Mechanical support could be provided so that the gasket 80 is not dislodged by the liner during installation.

The butyl adhesive or viscous sealant referred to could be replaced by any suitable substitutes, particularly silicone and polyurethane based polymers. Hydrophillic seals, particularly polyurethane based could also be used, as could an epoxy putty.

It will be understood too that although the lining of water pipes has been referred to, the invention is equally applicable to other mains for other fluids such as oil, gasoline or gas.

The benefits of the embodiments described outlined hereinbefore with reference to the drawings are inter alia: <BR> <BR> Some lining systems make use of a sacrificial sleeve, which protects the liner's outer surface during installation; and remains in place with the liner. The"post-liner"gasket, described herein, ensures that no leak-path exists between the outer surface of the liner and inner surface of the sacrificial sleeve. Potentially, even restraining bands, used to keep some systems in a"C"configuration, can cause a leak-path if the "pre-liner"gasket were used.<BR> <BR> <P>The"post-liner"gasket has potential for a wide range of liner wall thickness, whereas the"pre-liners"are less suitable for very thick/tough liner materials, i. e. more difficult for a gasket's razor edge to penetrate the material.

It will be understood that further modifications are possible. Thus, instead of the device 5 many alternative methods can be considered, using remote controlled devices travelling inside the liner. One method would be the use of ultrasound. This would allow detection of the ferrule through the liner before cutting the liner, by a robotic device travelling in the main.

Ultrasound has been used for several applications, detecting cracks and determining the wall thickness of pipes.

An alternative to using ultrasound inside the lined pipe, would be to transmit a signal onto a stopcock or other installation which can be fitted outboard of the ferrule. The signal would be picked up by the robot inside the pipe. This had the advantage of component size, i. e. a much larger, more powerful, transmitter can be used.