WO2007066138A1

WO2007066138A1 - Method and apparatus for renovating a pipe or conduit

Info

Publication number: WO2007066138A1
Application number: PCT/GB2006/004616
Authority: WO
Inventors: Florian Büssing; Sebastian Büssing
Original assignee: Minova International Limited
Priority date: 2005-12-09
Filing date: 2006-12-11
Publication date: 2007-06-14
Also published as: DE102005058775A1

Abstract

A method, apparatus and inner pipe for renovating a pipe (1) or conduit makes it possible to deliver a filling material/multi-component resin (15) in a targeted manner to the place of use. This is provided by shaping the inner pipe (5) into the form of a trough before introducing it into the pipe section (3) to be renovated. The quantity of filling material/multi- component resin (15) is preferably selected while charging the trough (16), preferably via the pipe-charging connecting piece (26), so that the required quantity is provided at the point of use in order to fill the intervening space (14) and any cavities (11, 12). This precisely targeted filling process is provided by carrying out the reverse deformation of the trough-shaped inner pipe (5).

Description

METHOD AND APPARATUS FOR RENOVATING A PIPE OR

CONDUIT

The invention relates to a method for renovating a pipe or conduit, to an apparatus for carrying out said renovation and to an inner pipe used in said renovation. Pipes or conduits that require such renovation include those serving to transport fresh water, waste water, waste material, gas, oil or similar media. Conduits, pipes or pipelines such as those that transport fresh water, waste water, waste material, gas, oil or other media have a limited service life. In particular, in the case of such pipes or conduits laid in numerous towns of the German Federal Republic and other countries, said pipes or conduits are in some cases more than 100 years old. As a result of their long service life and the effects of wars, corrosion, pressure of heavy traffic and other stresses, a large number of these pipes and conduits have become damaged. This means that the medium transported in them reaches the subsoil and therefore the ground water. In particular in the case of sewerage and gas, this can cause major problems. These known pipes and conduits are located approximately one metre deep or more in the ground, meaning that replacing the pipes or conduits over their full length would only be possible at considerable expense. In addition, the pipes or conduits are commonly located near to or underneath roads and replacing them can cause severe disruption to traffic flow.

It is known from WO 96/06298 (PCT/EP95/03300) to introduce an inliner provided with spacer elements into these conduits, pipes or shafts and then to fill the intervening space with a hardenable composition or a curable plastics material. This plastics material is extended with filler. Many different kinds of plastics materials may be used for this purpose, some of which must be cured by radiation, heat or chemical means to obtain the necessary stability. A further known embodiment of an inliner or inner pipe having spacers is shown in DE 199 00 441 Al . It is apparent in particular from Figure 4 of this document that the space between the wall of the pipe or conduit and the outer wall of the inner pipe is filled with mortar. Here, too, the filling of the intervening space has the primary purpose of stabilising the new "inner skin" of the conduit or pipe. A control inliner is then drawn into this pipe, the inliner being introduced into the pipe in a manner known in the art, and is pressed against the inner wall of the pipe by means of compressed air or water. This control inliner is made of a flexible material the ends of which can be thermoplastically welded to the pipe itself, which is also formed of a plastics material. A disadvantage of this method is that although such a flexible material is easily deformable while being drawn into the pipe section to be renovated, its shape can only then be restored at considerable cost and complexity. Furthermore, the comparatively thin wall of this inner pipe cannot be used as a supporting wall. Finally, in particular with lengths in excess of 100 m, it is extremely difficult to fill the comparatively narrow intervening space reliably with cement or even with plastics material, or to fill any cavities that may have formed. In the great majority of cases the result is, at best, very unsatisfactory.

The present invention seeks to provide a method for renovating a pipe or conduit which is simple, reliable to implement and at the same time renders cavities safe. The present invention also seeks to provide an apparatus and an inner pipe suitable for use in the method.

According to the invention there is provided a method which comprises the steps of:

(a) shaping an inner pipe into the form of a trough, (b) dispensing a filling material into the trough-shaped inner pipe,

(c) introducing the trough-shaped inner pipe into the pipe or conduit to be renovated, and

(d) carrying out reverse deformation of the trough-shaped inner pipe such that the filling material occupies the space between an outer surface of the inner pipe and an inner surface of the pipe or conduit, The dispensing step (b) may carried out either before or after the introducing step (c) .

One or more supply lines for dispensing filling material may be placed in the trough-shaped inner pipe before the introducing step (c), the one or more supply lines being withdrawn along the trough-shaped inner pipe whilst filling material is dispensed from them after the introducing step (c) .

The outer surface of the inner pipe may be fitted with one or more spacers for controlling the distance between the outer surface of the inner pipe and the inner surface of the pipe or conduit to be renovated.

The filling material may have delayed hardening properties. The filling material may comprise a single or multiple component resin.

The trough may be U-shaped or V-shaped.

The inner pipe may comprise a material having shape memory. The material having shape memory may be a plastic material. The reverse deformation of the inner pipe in step (d) may be carried out by filling the inner pipe with a fluid. In step (d) the inner pipe may be closed at both ends before reverse deformation is carried out and is provided with a fluid inlet valve. The fluid may be compressed air.

In order to attach connecting pieces to the renovated pipe or conduit, the following step (e) may be carried out after step (d) :

(e) drilling through the renovated pipe or conduit and connecting a sealed or sealable connecting piece to the hole formed in the pipe or conduit.

The quantity of filling material dispensed into the trough-shaped inner pipe may exceed by 0.5-25% the amount required to fill the space between the outer surface of the inner pipe and the inner surface of the pipe or conduit once reverse deformation has taken place.

The pipe or conduit to be renovated may be provided at least one end with an overflow pipe, the flow of filling material from the overflow pipe preferably being monitored. The application of pressure or a vacuum to the overflow pipe may aid uniform distribution of the filling material.

The inner pipe may be provided with markers for indicating the deformation points for shaping the inner pipe into the form of a trough. The inner pipe may be provided with one or more markers for limiting or indicating the level of filling material to be dispensed into the trough.

The introducing step (c) may include inserting a light conductor or fibreglass cable into the pipe or conduit to be renovated.

The following step (f) may be carried out after step (d) : (f) checking the renovated pipe or conduit for leaks or damage by activating the light conductor or fibreglass cable and detecting light inside the renovated pipe or conduit.

In one aspect of the method of the present invention an inner pipe is introduced into a pipe or conduit section to be renovated, which inner pipe is shaped in order to be introduced and spacers associated with its outer wall are then applied against the wall of the pipe or conduit, whereupon the space between the wall of the pipe or conduit and the outer wall of the inner pipe is filled. The inner pipe, which has inherent stability in its inserted state, is shaped before or during its introduction into the pipe or conduit section to produce a kind of trough conveyor belt. The resulting conveying space or trough is charged with a filling material that has delayed hardening properties. The restoration of the shape (also called reverse deformation) of the inner pipe after it has reached its final position is assisted by filling its interior space with a medium.

One aspect of the method of the present invention relates to the possibility of introducing the inner pipe that effects the renovation of the pipe or conduit at the same time as the filling material, i.e. the plastics material, into the pipe section to be renovated. The filling material can therefore be delivered at the intended location in the intervening space between the outer surface of the inner pipe and the inner surface of the pipe or conduit and at the same time can fill any cavities that have formed in the material surrounding the pipe or conduit. A sufficient quantity of this filling material can be introduced into the conveyor belt formed by the trough- shaped inner pipe. The advantageously uniform distribution of the filling material over the entire circumference of the pipe or conduit is automatically effected by the reverse deformation of the inner pipe. This reverse deformation may occur of its own accord through the inherent stability or rigidity of the inner pipe or may be assisted. The reverse deformation occurs and is fully completed before the filling material hardens since the hardening would make the reverse deformation impossible. With the aid of this method a renovated pipe or conduit is made available which has an advantageously smooth inner wall. The low frictional resistance of the inner wall means that the medium to be transported in the renovated pipe or conduit can be conveyed in sufficient quantity, and at least in the same quantity that was passed through the pipe or conduit previously. The heat generated during the curing of the filling material is harmless to the inner pipe because the method may be operated using a resin having low reaction temperatures, for example below 140°C, especially below 100°C. A silicate resin which ensures such a low reaction temperature of for example below 80° C may be used. It is also possible to use a suitably modified cement or mineral-bound construction material to which retarding agents have been added in order to prevent the cement hardening before the restoration of the shape of the inner pipe. Above all, it is possible with this method to renovate both open (unpressurised) conduits and pressure pipes made of a wide variety of materials reliably and without excessive cost or complexity.

A single-component or, in particular, a multi-component resin, the curing time of which is easily adjustable, may be used.

According to one embodiment of the invention the trough-shaped inner pipe for receiving the filling material is in the form of a U-shaped conveyor belt. This shaping or folding is carried out at the entrance of the pipe or conduit section to be renovated, or of the access shaft produced at that location, by means of suitable machines which will be discussed in more detail hereinafter. The U-shaped conveyor belt thus produced is then drawn through the pipe or conduit section to be renovated to its other end. The filling material located in the trough is distributed into the slot- shaped or annular intervening space by reverse deformation of the inner pipe. As a result of the force with which the reverse deformation is carried out it can be ensured that "surplus" filling material can reliably penetrate any cracks, joints and cavities present in the adjacent material. This assists the necessary securing of the pipe or conduit and helps to avoid damage to roads through subsidence. The U-shaped conveyor belt provides an advantageous space for introducing the filling material into the pipe or conduit. The conveyor belt can also be used for non-circular cross-sections, in which case the inner pipe should advantageously be shaped in the form of the original pipe or conduit. For such a specially- shaped inner pipe the shape-restoring effect is also reliably provided in order to ensure filling of the intervening space.

According to another embodiment of the invention, the reverse deformation of the inner pipe is ensured by producing the inner pipe from a plastics material having a shape memory effect. Practically all cross- linked plastics materials, for example PE (polyethylene), PU (polyurethane) , PA (polyamide), PTFE (polytetrafluoroethylene) and others, possess such memory effects. This means that the invention can be implemented with plastics materials which are commonly available.

According to one aspect of the invention the shape-restoring effect is assisted. In order to achieve this the inner pipe is sealed at both ends and then charged with compressed air, cold or hot water, or with medium having the same effect. This does not cause bulging or expansion of the inner pipe but only restoration of its shape. This means that, when viewed around the circumference of the inner pipe, the filling material can solidify in a uniform distribution in the intervening space between the outer surface of the inner pipe and the inner surface of the pipe or conduit to be renovated in order to produce the stable structure required. Instead of pouring the filling material into the trough of the shaped inner pipe immediately and therefore using the inner pipe simultaneously as a conveyor pipe, it is also possible according to the invention to place into the conveying space or trough of the inner pipe, after shaping the inner pipe, one or more supply lines for introducing the filling material. Once the final position of the supply lines has been reached, they are slowly withdrawn from the conveying space/trough while dispensing the filling material before or in the early stage of the reverse deformation of the inner pipe. This also makes it possible to deploy the individual components of a filling material via the supply lines and to dispense said components in a specified manner where appropriate according to the state of reverse deformation of the inner pipe. In this case, the components of the filling material may be mixed in such a way that they solidify rapidly in a targeted manner within a given period and thus completely fill the intervening space. Filling materials can then advantageously be used which increase in volume as they harden in order additionally to ensure a correspondingly close application of the inner pipe to the wall of the pipe or conduit, or filling of adjacent cavities. Both during the introduction of filling material when inserted at the same time as the inner pipe and after the withdrawal of the supply lines from the corresponding trough in the inner pipe, according to one aspect of the invention the inner pipe shapes itself in such a way that any existing branches or connections to buildings are also sealed. These may, however, be easily reconnected by drilling through the wall of the inner pipe from outside to make connections to buildings or to connect branches, and then, if necessary, attaching a connecting piece that is sealed or sealable. The pipe system is then again complete, making it possible to completely renovate and reconnect a pipe or conduit system in a relatively short time. To ensure that not only the intervening space but also any cavities present are optimally filled, another aspect of the invention provides that the quantity of filling material introduced exceeds the pre-calculated requirement for the intervening space by 0.5-25%, and that during reverse deformation the overflow pipes preferably installed at both ends are monitored. This means that the system operates with an appropriate "surplus", so that any cavities present behind the defective conduit are in all cases completely or at least largely filled with the filling material. It is^" also possible to position the surplus in a targeted way where corresponding cavities are expected after the preliminary work. In other areas a surplus of only 0.5 to 3% is used. Since the filling material may exhibit delayed hardening, according to the invention the surplus material may be reliably captured at the ends. If surplus material appears, or is found to egress from the overflow pipe, it can be ascertained that the intervening space and the cavities are optimally filled.

By the term "delayed hardening" it is meant that the material used does not fully harden until reverse deformation has been effected, i.e. the material is still soft enough to reliably fill the space between the inner pipe and the pipe or conduit being renovated whilst also at least partially filling any cavities. The material may optionally comprise a retarding agent to delay hardening.

The shaping or deforming of the inner pipe is simplified according to one aspect of the present invention by providing on the inner pipe spacers that indicate the deformation points. Using these spacers, the pairs of rollers can then be applied in a targeted way and maintained in the optimum position. This means that the desired conveyor belt with the trough can be produced downstream of the pairs of rollers and can then be charged with the filling material. It is also advantageous for introducing the filling material into the trough if filling or charging level indicators, preferably suitably marked spacers, are provided on the inner pipe. This marking can be effected by means of colour, shape, deformation or incisions. The handling of such a shapable inner pipe is thereby considerably simplified.

According to the present invention there is also provided an apparatus for renovating a pipe or conduit comprising: (a) shaping means for shaping an inner pipe into the form of a trough,

(b) a dispenser for dispensing a filling material into the trough- shaped inner pipe,

(c) transporting means for introducing the trough-shaped inner pipe into the pipe or conduit to be renovated, and

(d) shape-restoring means for carrying out the reverse deformation of the trough-shaped inner pipe .

The shaping means may comprise a pair of rollers. In addition, the inner pipe may be sealable such that it is airtight and is provided with a fluid inlet valve.

The dispenser may comprise one or more retractable supply lines that are adapted to sit in the trough-shaped inner pipe and dispense filling material along the trough whilst being retracted. The dispenser may comprise at least two supply lines each dispensing a different component and a static, free flow or dynamic mixer for mixing the two or more components.

The transporting means additionally comprise means for introducing a light conductor or fibreglass cable for detecting leaks in or damage to the renovated pipe or conduit. The light conductor or fibreglass cable can be used for the transmission of data and information.

To carry out the method, according to one aspect of the invention an apparatus is used in which, in addition to the pair of shaping rollers, a traction device and a device for filling the intervening space are present. The pair of rollers is adjustable to form from the inner pipe a kind of conveyor belt with a trough. A connecting piece for dispensing a filling material with delayed hardening is provided downstream of the pair of rollers. Both ends of the inner pipe, after its reverse deformation when it again has inherent stability, can be fitted with airtight sealing caps. At least one of the caps has a connecting piece for inflation. The apparatus provides a pair of rollers which are able to produce a quite specific form of shaping of the inner pipe. Filling material can subsequently be dispensed via an associated connecting piece into the trough produced. To assist the reverse deformation of the inner pipe, which now has inherent stability, the inner pipe is sealed with an airtight sealing cap and is "inflatable" by means of the apparatus and a connection piece for inflation. It is self-evident that in this context "inflation" means only restoration of shape, not a deformation going beyond such restoration. The inflation step is preferably long enough for the filling material to cure. All this is ensured by the appropriate configuration of the apparatus, thereby permitting the renovation of pipes and conduits with comparatively low cost and complexity. Whereas conduits usually have sufficiently large cross sections, pipes having relatively small diameters, as low as 50-100 mm, can also be renovated with the method and apparatus according to the invention.

As mentioned earlier, a simple filling level indicator may be provided using a connecting piece with an overflow pipe on the sealing caps and/or the ends of the inner pipe. If filling material emerges from the overflow pipe, the operating team knows that the intervening space has been completely filled. This provides the possibility of obtaining corresponding experiential values which can be utilised in a specified way in subsequent use.

Instead of pouring the filling material into the trough and then drawing the whole inner pipe in this state into the pipe or conduit to be renovated, according to another aspect of the invention is also possible for the connecting piece for charging the trough to be connected to one or two supply lines resting in the shaped inner pipe. These may be configured to be retractable with the supply line or lines from the end of the inner pipe. An apparatus configured in this way has the advantage that the filling material can be conveyed to the point of use in its separate components and subsequently discharged and mixed in situ. In the great majority of cases this dispenses with the need for incorporating retarding agents. By carefully timing the introduction of compressed air, for example, the reverse deformation process of the inner pipe can be controlled in such a way that the individual components emerge from the supply lines shortly before that process begins. The components are mixed and they then flow into or are pressed into the intervening space and they subsequently harden.

This uniform filling is assisted in particular in that the supply lines are designed to be guided in the trough of the inner pipe and retracted from its end slowly, with complete filling of the intervening space and any cavities present in the surrounding soil. This ensures that the two or more supply lines, or the single supply line, is/are moved while so positioned so that the necessary mixing effect reliably occurs. The mixed filling material subsequently hardens at precisely the correct point. According to the present invention there is further provided an inner pipe for renovating pipes and conduits adapted such that it can be shaped into the form of a trough, introduced into a pipe or conduit to be renovated and reverse deformed such that it is restored to its original shape.

The cross-section of the inner pipe may be any shape. Examples include oval, egg-shaped, round, square or rectangular. The pipe to be renovated may be formed of any material, for example steel, iron, cast iron, other metals, plastics, brick, cement, stoneware etc.

The outer surface of the inner pipe may be provided with one or more spacers for controlling the distance between an outer surface of the inner pipe and an inner surface of the pipe or conduit to be renovated. The inner pipe may comprise a material having shape memory. The material having a shape memory may comprise a plastic material. The inner pipe and/or the one or more spacers may comprise a cross-linked plastic. The cross-linked plastic may for example be a polyethylene, a poly amide or a polyurethane. The inner pipe and/or the one or more spacers may comprise Kevlar, a plastic coated with Kevlar or a polyamide mixed with Kevlar, boron or other fibres.

The inner pipe may be formed with weak points for assisting the shaping of the inner pipe into the form of a trough. The inner pipe may be fitted with markers that indicate the weak points.

The inner pipe may be provided with one or more markers that limit or indicate the level of filling material to be dispensed into the trough. At least one end of the body of the inner pipe may be reinforced. The inner pipe may be fitted with attached or attachable coupling flanges. The inner pipe may comprise a light conductor or fibreglass cable. Any other cable suitable for data transmission may also be used. The inner pipe may be provided with a connecting piece comprising an overflow pipe for excess filling material.

A further group of features relates to the inner pipe. In one aspect of the invention it is provided that the pipe wall is made entirely or in predetermined sections of a plastics material that has shape memory effect or produces such an effect through treatment before use. In the case of pipes and conduits having a diameter of 1 m or more, it may be advantageous not to make the entire pipe or the entire pipe wall from the material having shape memory. In this case it is sufficient to produce from this material only the section of the pipe wall which is actually required for the shaping. This section can be distinguished by colour marking or similar means so that it can be easily recognised for further processing. This has the advantage that specially stiffened sections of pipe may optionally be used in order to increase the stability or strength of the pipe as a whole without resulting in the loss of the advantages gained from using the material having shape memory.

According to one aspect of the invention it is advantageous to produce the entire pipe wall as well as the spacers from a cross-linked plastics material such as PE, PA, PTFE or PU. This configures the entire inner pipe optimally for the intended use. This configuration also has the advantage of allowing the combination of wall parts and spacers made of the same material into a compact unit. In this case the spacers, these may be connected "rigidly" to the pipe wall such that they can absorb the forces which can arise when pressing against the wall of the pipe. It is also important to configure the spacers, through the selection of their thickness and overall shape, in such a way that they ensure uniform all- round thickness of the intervening space.

According to another aspect of the invention, filling materials having relatively high reaction temperatures can also be used if the pipe wall and/or the spacers are made of Kevlar (aramid textile) or a plastics material coated with Kevlar. The use of such materials means that the pipe wall and the spacers can withstand temperatures of 150-300⁰C and in some cases more, without being deformed or losing useful properties.

To assist in the reverse deformation process, it is possible according to one aspect of the invention for the pipe wall to have weak points favouring the shaping and thus the formation of the trough. The weak points may be a thinning of the material or the like, meaning that the material automatically deforms at these points first during the folding process. This predefines and ensures that the shaping of the inner pipe occurs in the required way. The weak points are applied precisely at the location of the shaping points, i.e. the points where the inner pipe is to be shaped in a specified manner. It is additionally provided that spacers indicating the shaping points or weak points are provided on the pipe wall so that during processing of such inner pipes it is quickly and immediately apparent where the weak points important for shaping are located. A further advantageous configuration is that in which spacers limiting or at least predefining the charging of the trough are provided on the pipe wall. This means that the overfilling or underfilling of the trough can be reliably avoided when introducing the filling material. In this case, it is possible for a suitable shape or colour to be imparted to the spacers, or for sensors to be associated therewith. The sensors can transmit signals to the charging machine in order to prevent overfilling or underfilling. The reverse deformation of the inner pipe may be assisted by "inflating" the inner pipe. In order to assist with this procedure the ends of the pipe body are reinforced, and in particular are provided with an attached or attachable coupling flange. The sealing caps to which the compressed air supply is attached can then be connected to this coupling flange. The coupling flange may optionally also be used to connect the inner pipe to a neighbouring inner pipe, or the coupling flange is sawn off or otherwise detached after completion of the works and the pipe is, for example, welded, bonded or otherwise connected to the neighbouring pipe.

In some aspects the present invention is distinguished in particular by the fact that it provides a method which is simple and reliable to operate, by which not only the space between the inner pipe and the pipe to be renovated is filled, but any cavities that may have formed in the soil are filled at the same time. A filling material is transported precisely to the place of use where it is pressed in a targeted manner into the intervening space or the cavity, the inner pipe itself being used for pressing and thus making additional auxiliary means superfluous. It is further advantageous that the restoring or reverse deformation effect of the inner pipe can be used to distribute the filling material transported with it evenly over the entire circumference, and to deliver it precisely, for example, into open cavities. A solidified combined pipe or combined conduit which absorbs the necessary forces is therefore provided. The apparatus provided for this purpose is advantageous because it is simple, it operates with means generally available and because it does not demand a high level of technology. In addition, however, it is possible by incorporating suitable sensors to monitor and control the entire operation of inserting the inner pipe into a pipe or conduit to be renovated. Another advantage of one aspect of the invention is that that inner pipes used in this method are made of a material which has low friction in relation to the medium to be transported and therefore ensures that the same quantity of medium can flow into or from the pipe, despite its smaller cross-section. Multi- component filling materials can be used in the method and with the apparatus and the inner pipe whether their hardening temperatures are below or above 100⁰C. As mentioned previously, filling materials having hardening temperatures above 300⁰C may be used. Moreover, the filling material may be delivered by means of the method and apparatus according to the invention in a specified quantity precisely to the locations where it is required also in order to fill existing cavities and the intervening space between the inner pipe and the pipe or conduit being renovated.

Further details and advantages of the invention are apparent from the following description of the associated drawings in which a non-limiting preferred embodiment is illustrated by way of example, and in which:

Figure 1 is a schematic representation of an apparatus for implementing the method of the invention showing the introduction of the inner pipe on the right-hand side and the renovated pipe or conduit on the left-hand side;

Figure 2 shows in cross-section a trough-shaped inner pipe charged with a filling material/multi-component resin;

Figure 3 shows in cross-section a trough-shaped inner pipe with supply lines for dispensing filling material placed in the trough-shaped inner pipe; Figure 4 shows a partial section through a conduit or pipe with the inner pipe in its final position and spacers having various configurations, and Figure 5 shows a trough-shaped inner pipe deformed approximately at right angles and charged with filling material/multi-component resin.

Figure 1 shows in a schematic representation an apparatus with which a given section 3 of a pipe 1 laid in the ground 2 is renovated. An inner pipe 5 that has been shaped into the form of a trough is introduced into the pipe section 3. Upon reverse deformation, the outer wall 7 of the inner pipe 5 approaches the wall 4 of the pipe 1 in such a way that a predefined intervening space 14 remains therebetween. This intervening space 14 is filled with a multi-component resin 15, it being possible to predetermine precisely the volume of the intervening space 14 because spacers 8, 9, 10 are attached at predefined intervals to the outer wall 7 of the inner pipe 5 or form part of the inner pipe itself. The interior 6 of the inner pipe 5 is charged with a medium in such a way that the reverse deformation process is assisted. As a result, the appropriate quantities of multi-component resin 15 penetrate not only the intervening space 14 but also the cavities 11, 12.

The right-hand side of Figure 1 shows the cavity 12 unfilled because in this section of the drawing the trough-shaped inner pipe 5 is being introduced into the pipe 1 in the introducing direction 25. On this side of the diagram the spacers 9 and 10 can be seen.

In deviation from all known methods, in this method the multi-component resin 15 is pumped in a targeted manner precisely to the area where it is required. This is possible because the shaping of the inner pipe 5 into the form of a trough 16, as can be seen in Figure 2, enables the trough 16 to be charged with the multi-component resin 15 in an amount such that precisely the required quantity of resin is provided at the point of use. In Figure 1, seen as a top view, it can be noted that, as a result of the size of the cavity 12, a correspondingly large quantity of multi-component resin 15 must be made available in this area to ensure extensive or even complete filling of the intervening space 14 and the cavity 12.

Sealing caps 27 are provided at the ends 17, 18 of the inner pipe 5 so that compressed air can be introduced in a controlled manner into the interior 6. For this purpose an inflation connecting piece 28 to which the compressed air line connects is provided. Also provided is a connecting piece 29 for an overflow pipe 30 for detecting when the filling of the intervening space 17 and the cavities 11, 12 is sufficient.

The device 31 for filling the intervening space consists of the pipe- charging connecting piece 26 and the trough-shaped inner pipe 5 itself. The pipe-charging connecting piece 26 is arranged downstream of the pairs of rollers 23, 24 which ensure that the trough 16 required for containing the multi-component resin 15 is formed by the shaping of the inner pipe 5.

The dimensions of the wall 32 of the inner pipe 5 are such that the rigidity of the inner pipe 5 is sufficient to maintain the trough shape. This rigidity can be optimised by providing sections 33 having memory effect and sections 34 without memory effect around the circumference of the inner pipe 5. In addition, the shaping of the inner pipe 5 into the form of a trough 16 may be assisted by the provision of weak points 35, 36, which predefine the deformation points 37 and facilitate the folding of the inner pipe 5 in a specified manner. The weak points are provided around the circumference of the inner pipe 5. Such a trough-shaped inner pipe 5 can have almost any desired shape depending upon how the pairs of rollers 23, 24 are used or configured. Figures 2 and 3 show an almost V- shaped configuration and Figure 5 shows a U-shaped configuration. In Figure 5 the inner pipe 5 has been shaped almost into a right-angle at the deformation points for 37, 37' . This results in a very large trough 16 into which a large quantity of multi-component resin 15 can be poured. The use of an inner pipe 5 configured in this way can be useful where large cavities 11 , 12 are anticipated. Also shown in Figure 2 is light conductor or fibreglass cable 50 for detecting whether any leaks have occurred in the newly fitted inner pipe 5, and if so where those leaks are. The light conductor or fibreglass cable can be used for the transmission of data and information. Whereas according to Figure 2 the trough 16 is charged with a suitably liquid multi-component resin with delayed curing properties, according to Figure 3 an arrangement of supply lines 20, 21 is provided in the trough 16 for dispensing the filling material once the trough-shaped inner pipe has been introduced into the pipe or conduit to be renovated. It is also possible for only one supply line 20 to be used, or more than two, depending on how many components are required. Generally one pipe per component is used. These supply lines 20, 21, together with the pipe- charging connecting piece 26 connected thereto, are withdrawn from the pipe 1 whilst filling material is dispensed into the trough 16. This operation takes place sufficiently slowly to ensure both that the individual components of the resin are mixed and that they can be dispensed in sufficient quantity. This mixing may be assisted, for example, by a static, free flow or dynamic mixer. After the renovation operation is completed, the pipe body 39 - as can be seen on the left-hand side of Figure 1 and in Figure 4 - is stabilised by the multi-component resin 15 in such a way that an optimally renovated pipe 1 is produced. Figure 4 shows spacers 8, 8' , 8" , 8'" having various configurations according to the application for which they are provided. The spacers can be used to provide or indicate a weak point 35, 36 or to serve as charging level indicators, as shown, for example, in Figure 2.

The pipe body 39 is introduced into the pipe 1 from access shaft 42 and is drawn into the pipe from the direction of access shaft 43. This is made possible by a traction device 41 (only indicated here) which can take various forms and, in the present case, must be connected to the end 18 of the inner pipe 5.

On completion of the introducing operation the coupling flange 40 is fitted. The coupling flange 40 occludes the interior 6 of the inner pipe 5 in such a way that the inflation connecting piece 28 can then be attached.

The upright guide walls 44 shown in Figure 3 ensure that the two or more supply lines 20, 21 occupy positions which ensure reliable and targeted dispensing of the components of the multi-component resin 15. The diameter of the lines is shown here only as an example and can be varied according to the particular application.

Claims

1. A method for renovating a pipe or conduit, the method comprising the steps of:

(a) shaping an inner pipe into the form of a trough,

(b) dispensing a filling material into the trough-shaped inner pipe,

(d) carrying out reverse deformation of the trough-shaped inner pipe such that the filling material occupies the space between an outer surface of the inner pipe and an inner surface of the pipe or conduit, wherein the dispensing step (b) is carried out either before or after the introducing step (c) .

2. . A method as claimed in claim 1, wherein the dispensing step (b) is carried out before the introducing step (c) .

3. A method as claimed in claim 1, wherein the dispensing step (b) is carried out after the introducing step (c) .

4. A method as claimed in claim 3, wherein one or more supply lines for dispensing filling material are placed in the trough-shaped inner pipe before the introducing step (c) , the one or more supply lines being withdrawn along the trough-shaped inner pipe whilst filling material is dispensed from them after the introducing step (c) .

5. A method as claimed in any one of the preceding claims, wherein the outer surface of the inner pipe is fitted with one or more spacers for controlling the distance between the outer surface of the inner pipe and the inner surface of the pipe or conduit to be renovated.

6. A method as claimed in any one of the preceding claims, wherein the filling material has delayed hardening properties.

7. A method as claimed in claim 6, wherein the filling material comprises a single or multiple component resin.

8. A method as claimed in any one of the preceding claims, wherein the trough is U-shaped or V-shaped.

9. A method as claimed in any one of the preceding claims, wherein the inner pipe comprises a material having shape memory.

10. A method as claimed in claim 9, wherein the material having shape memory is a plastic material.

11. A method as claimed in any one of the preceding claims, wherein the reverse deformation of the inner pipe in step (d) is carried out by filling the inner pipe with a fluid.

12. A method as claimed in claim 11 , wherein in step (d) the inner pipe is closed at both ends before reverse deformation is carried out and is provided with a fluid inlet valve.

13. A method as claimed in either claim 11 or claim 12, wherein the fluid is compressed air.

14. A method as claimed in any one of the preceding claims, wherein, in order to attach connecting pieces to the renovated pipe or conduit, the following step (e) is carried out after step (d) : (e) drilling through the renovated pipe or conduit and connecting a sealed or sealable connecting piece to the hole formed in the pipe or conduit.

15. A method as claimed in any one of the preceding claims, wherein the quantity of filling material dispensed into the trough-shaped inner pipe exceeds by 0.5-25% the amount required to fill the space between the outer surface of the inner pipe and the inner surface of the pipe or conduit once reverse deformation has taken place.

16. A method as claimed in claim 15, wherein the pipe or conduit to be renovated is provided at least one end with an overflow pipe, the flow of filling material from the overflow pipe preferably being monitored.

17. A method as claimed in any one of the preceding claims, wherein the inner pipe is provided with markers for indicating the deformation points for shaping the inner pipe into the form of a trough.

18. A method as claimed in any one of the preceding claims, wherein the inner pipe is provided with one or more markers for limiting or indicating the level of filling material to be dispensed into the trough.

19. A method as claimed in any one of the preceding claims, wherein the introducing step (c) includes inserting a light conductor or fibreglass cable into the pipe or conduit to be renovated.

20. A method as claimed in claim 19, wherein the following step (f) is carried out after step (d) :

(f) checking the renovated pipe or conduit for leaks or damage by activating the light conductor or fibreglass cable and detecting light inside the renovated pipe or conduit.

21. An apparatus for renovating a pipe or conduit comprising: (a) shaping means for shaping an inner pipe into the form of a trough,

(d) shape-restoring means for carrying out the reverse deformation of the trough-shaped inner pipe.

22. An apparatus as claimed in claim 21, wherein the shaping means comprise a pair of rollers.

23. An apparatus as claimed in either claim 21 or claim 22, wherein the inner pipe is sealable such that it is airtight and is provided with a fluid inlet valve.

24. An apparatus as claimed in any one of claims 21 to 23, wherein the dispenser comprises one or more retractable supply lines that are adapted to sit in the trough-shaped inner pipe and dispense filling material along the trough whilst being retracted.

25. An apparatus as claimed in claim 24, wherein the dispenser comprises at least two supply lines each dispensing a different component and a static, free flow or dynamic mixer for mixing the two or more components .

26. An apparatus as claimed in any one of claims 21 to 25, wherein the transporting means additionally comprise means for introducing a light conductor or fibreglass cable for detecting leaks in or damage to the renovated pipe or conduit.

27. An inner pipe for renovating pipes and conduits adapted such that it can be shaped into the form of a trough, introduced into a pipe or conduit to be renovated and reverse deformed such that it is restored to its original shape.

28. An inner pipe as claimed in claim 27, wherein an outer surface of the inner pipe is provided with one or more spacers for controlling the distance between an outer surface of the inner pipe and an inner surface of the pipe or conduit to be renovated.

29. An inner pipe as claimed in either claim 27 or 28, wherein the inner pipe comprises a material having shape memory.

30. An inner pipe as claimed in claim 29, wherein the material having a shape memory comprises a plastic material.

31. An inner pipe as claimed in any one of claims 28 to 30, wherein the inner pipe and/or the one or more spacers comprise a cross-linked plastic.

32. An inner pipe as claimed in claim 31, wherein the cross-linked plastic is a polyethylene, a polyamide or a polyurethane.

33. An inner pipe as claimed in any one of claims 28 to 32, wherein the inner pipe and/or the one or more spacers comprise Kevlar, a plastics material coated with Kevlar, a polyamide mixed with Kevlar, or boron.

34. An inner pipe as claimed in any one of claims 28 to 33, wherein the inner pipe is formed with weak points for assisting the shaping of the inner pipe into the form of a trough.

35. An inner pipe as claimed in claim 34, wherein the inner pipe is fitted with markers that indicate the weak points.

36. An inner pipe as claimed in any one of claims 27 to 35, wherein the inner pipe is provided with one or more markers that limit or indicate the level of filling material to be dispensed into the trough.

37. An inner pipe as claimed in any one of claims 27 to 36, wherein at least one end of the pipe body is reinforced.

38. An inner pipe as claimed in any one of claims 27 to 37, wherein the inner pipe is fitted with attached or attachable coupling flanges.

39. An inner pipe as claimed in any one of claims 27 to 38, wherein the inner pipe comprises a light conductor or. fibreglass cable.

40. An inner pipe as claimed in any one of claims 27 to 39, wherein the inner pipe is provided with an connecting piece comprising an overflow pipe for excess filling material.