Method for reconditioning a piping

Abstract

The invention relates to a method for reconditioning a leaking and / or damaged area of a piping, comprising at least the following steps: a) providing a bellows structure; b) positioning the bellows structure in the interior of the piping adjacent to the leaking and / or damaged area; c) expanding the bellows structure until the bellows structure seals the piping; d) introducing a curable material into the interior of the piping in the region of the leaking and / or damaged area; e) curing the curable material; and f) at least partially cutting free the interior of the piping.

Description

D e s c r i p t i o n Summary: Method for repairing a leaky and / or damaged section of a pipeline, comprising at least the following steps: - Providing a bellows body - Positioning the bellows body in the interior of the pipeline adjacent to the leaky and / or damaged section - Expanding the bellows body until the bellows body seals the pipeline - Introducing a curable material into the interior of the pipeline in the area of the leaky and / or damaged section - Curing the curable material - At least partially freeing the interior of the pipeline The method is particularly suitable in the field of trenchless rehabilitation of leaky and / or damaged non-walkable pipelines, such as defective sewage pipes. However, the method is not limited to a specific type of pipeline or a specific area of application. A pipeline is understood to be a hollow body through which a gaseous, liquid or viscous fluid or a solid-liquid mixture (e.g., sewage) can be transported along a predetermined route. Pipelines are used in private households, in the public drinking water and sewage supply sector, and in industrial plants. The present method can be used for pipelines made of different materials, such as metal, ceramic or plastic. Various methods for repairing leaky and / or damaged sections on an inner wall of a pipeline are already known in the prior art, in particular the pipe-in-pipe method, in which a pipe with an inner diameter smaller than that of the existing pipe is pulled or pushed into the existing pipe until this pipe covers the leaky and / or damaged section on the existing pipe. However, this method has the disadvantage that it regularly leads to a reduction of the pipe inner diameter in the area of the newly inserted pipe and that deposits can form at the edge of the inserted pipe. In addition, this method can only be used for straight pipelines. Finally, a reliable seal between the two pipes cannot be guaranteed, so that liquid or gas can escape between the nested pipelines via the damaged and / or leaky section of the pipeline. Furthermore, the pipe bursting method is known in the prior art, in which a hydraulic expander is inserted into the interior of the existing pipeline, causing the existing pipe to burst when it expands, and a new pipe is then pulled into the space created in this way. However, this method does not ensure that the structures surrounding the pipe wall are not also affected when the pipe wall of the existing pipe breaks. It is also difficult to sufficiently seal the areas between the remaining existing pipe and the newly inserted pipe. WO1995 / 027167A1 describes a method in which a sewer rehabilitation robot has a carrying device in which a viscous sealing compound is brought to the area of the leaky and / or damaged section and the sealing compound is subsequently pressed against the inner wall of the pipeline by means of an expandable expansion body. After curing, the expansion body is contracted and removed from the pipeline again. This method has the disadvantage that the applied sealing compound settles on the inner wall of the pipeline, thereby narrowing the inner diameter of the pipeline. Here too, deposits can form, particularly in the area of the applied sealing compound in sewage pipes, and clog the pipeline. Furthermore, prior-art methods are known, for example from DE 10 2020 206 094 A1, in which a flexible lining hose impregnated with a curable resin is inserted as a liner into the pipeline. After insertion, the lining hose is expanded so that it fits snugly against the inner wall of the pipeline and presses the lining hose impregnated with curable resin against the inner wall of the pipeline. Once the resin has cured, the lining hose can then be removed from the pipeline. DE 10 2020 106 094 A1 describes how an inflatable rubber bellows is arranged on a rehabilitation packer that can be moved or shifted within the pipe. Resin-impregnated rehabilitation mats are arranged on the outer circumference of the rubber bellows, which can be pressed against the inner wall of the pipe when the rubber bellows is inflated and cure there. In addition, the resin can penetrate cracks or open areas in the pipe when the rehabilitation mat is pressed against the inner wall of the pipeline. After removing the rehabilitation packer and the rubber bellows, the rehabilitation mat and the resin remain at the previously leaky and / or damaged section of the pipeline. In both of the above methods for repairing pipelines, the inner diameter of the existing pipeline is reduced because the sealing compound is deposited over the entire surface of the inner wall of the pipeline. The sealing mat thus causes deposits to form in the area of the repaired section, which can clog the pipeline. Finally, WO2021 / 063448A1 discloses a device that has a storage container for PU material and an application opening. In this method for repairing pipelines, the device is inserted into the pipeline until the application opening is located in the area of the leaky and / or damaged section of the pipe wall. The PU material is then pressed from the storage container through the application opening against the inner wall of the pipeline. In another method, WO2021 / 063448A1 proposes that a cover element be arranged on a mobile carrier element, by means of which the PU material is pressed between the cover element and the inner wall of the pipeline. This method also inevitably leads to a narrowing of the inner diameter within the pipeline, which causes the problems described above. In addition, damaged pipe sections, root ingrowths or other foreign bodies remain inside the pipeline. WO1990 / 005874 A1 discloses a device for repairing a main line, which can also be used for repairing a leaky, corroded section of a branch pipe opening into the main line. US 5 527 133 discloses a tool with a covering plate having a discharge opening for a filler compound, to which a pressure line for injecting a sealing compound can be connected. In order to reduce the time required for the repair process, a second opening is provided adjacent to the discharge opening, which is sealed in an airtight and pressure-tight manner by an elastically deformable, balloon-like inflatable flat element, wherein a chamber connects to the second opening from the rear side and the chamber can be connected to a pressure source in order to inflate the flat element in a balloon-like manner. EP 2 287 511 A1 discloses a method and system for permanently sealing a branching sewage pipe at the connection between a branching sewage pipe and a main sewage pipe by providing a flexible bag made of a substantially liquid-tight material with a hose for supplying liquids into the flexible bag. The flexible bag defines a deflated state with a diameter smaller than the diameter of the branch pipe, and a filled state with a diameter at least equal to the diameter of the branch pipe. The method and system also comprise a remotely controlled pipeline device receiving the flexible bag in the deflated state. The remotely controlled pipeline device is inserted into the main sewage pipe so that the pipeline device can assume a position adjacent to the branch sewage pipe. The deflated flexible bag is inserted into the drain pipe with the aid of the pipeline device and filled via a hose with a water-based curing agent so that the curing agent can cure. Based on the foregoing, it is the object of the present invention to provide a method for repairing a leaky and / or damaged section on an inner wall of a pipeline in which the inner diameter of the pipeline is not substantially narrowed even after the repair. Furthermore, the present invention is based on the object of providing a reliable and durable method for sealing a leaky and / or damaged section on an inner wall of a pipeline, in which foreign bodies, such as damaged pipe sections, root ingrowths or other deposits, are reliably removed from the pipeline. Furthermore, the present invention is based on the object of also filling and sealing cavities located outside the pipeline in the area of the leaky and / or damaged section. The above objects are achieved according to the invention by a method with the features of claim 1. Advantageous embodiments and further developments of the method are disclosed in sub-claims 2 to 15. According to the invention, there is provided a method for repairing a leaky and / or damaged section of a pipeline, comprising at least the following steps: - Providing a bellows body - Positioning the bellows body in the interior of the pipeline adjacent to the leaky and / or damaged section - Expanding the bellows body until the bellows body seals the pipeline - Introducing a curable material into the interior of the pipeline in the area of the leaky and / or damaged section - Curing the curable material - At least partially freeing the interior of the pipeline A leaky section within the meaning of the present invention is a location on the inner wall of a pipeline through which either the contents of the pipeline can escape from the pipeline or foreign substances can penetrate into the pipeline from the outside. A damaged section within the meaning of this invention includes leaky sections, but can also extend to damage in its early stages, e.g., a longitudinal or transverse crack in the inner wall of the pipeline, which has not yet led to a leak in the pipeline. In the context of the present invention, a bellows body is understood to be a body whose volume can expand through the introduction of a substance. The volume expansion can be isotropic or anisotropic (e.g., along a preferred direction). In the case of a cylindrical bellows body with a circular cross-section in a pipeline, the volume expansion occurs primarily in the radial direction, i.e., in the direction of the inner wall of the pipeline. However, the expansion can also occur in all other spatial directions, i.e., both in the radial direction and in the direction along the bellows body. Preferably, the bellows body is made of a stretchable or elastic material. The bellows body should be dense and mechanically robust or abrasion-resistant to solids. It should enclose any substances introduced and ensure that the bellows body is not damaged by the inner wall of the pipeline and / or any solids inside it when it is inserted into the pipeline. The bellows body can, for example, be designed as a balloon or hose, wherein preferably one section of the bellows body has thinner material. At this section, the bellows body can preferably expand. For example, the bellows body has a triple coating, whereas the section opposite the inlet has only a double coating. In one embodiment, the bellows body is introduced into the pipeline by means of a protective device. This protective device can, for example, be designed as a protective cap. The protective cap can be approximately hemispherical in shape and can additionally have a taper at the opening, which serves to secure the bellows body inside the protective cap. The protective device can break open when the bellows body expands. Furthermore, the protective device can have a predetermined breaking point at which the protective device preferably breaks open when the bellows body expands. This predetermined breaking point is designed as a material taper, for example as a notch, perforation or score mark. The protective device is preferably made of plastic. When positioning the bellows body in the interior of the pipeline adjacent to the leaky and / or damaged section, the bellows body should be advanced until it has completely passed the leaky and / or damaged section. The bellows body should not cover the leaky and / or damaged section. Preferably, there should be a distance between the leaky and / or damaged section and the position of the bellows body. More preferably, this distance is approximately 10 cm. This distance ensures a complete repair of the leaky and / or damaged section. The bellows body should be positioned inside the pipeline in such a way that the leaky and / or damaged section on the inner wall of the pipeline is freely accessible and can subsequently be repaired. In a third step, after positioning the bellows body as described above, the bellows body is expanded until the bellows body seals the pipeline. In the context of the present invention, "sealing" means closing the pipeline so that substances cannot pass through the pipeline around the bellows body. In a next step, a curable material is introduced into the interior of the pipeline in the area of the leaky and / or damaged section. Sufficient curable material is introduced to cover the leaky and / or damaged section. In the context of this invention, the curable material can be any material that is initially liquid, foamy or pasty and that solidifies over time with or without the influence of atmospheric oxygen, water, light of a specific wavelength or chemical substances. Preferably, sufficient material is introduced so that an area of approximately 10 cm in addition to the leaky and / or damaged section in the pipeline is also covered. This ensures a complete and lasting repair of the leaky and / or damaged section. By introducing the curable material, this material can also penetrate through the leaky section into the area outside the pipeline and thus also fill any cavities in this area as far as possible. This ensures that the pipeline is also protected from the outside against renewed influences in this area. In addition, the curable material completely encloses any solids that have penetrated the pipeline, such as roots, stones or soil. The curable material spreads around these solids within the pipeline and embeds them. Once the material has cured, the solids can no longer move in this area of the interior of the pipeline. The curable material is then cured. Curing can take place with or without the influence of air, water, light of a specific wavelength or chemical substances. The method can thus be used for any suitable substance. In the following step, the interior of the pipeline is at least partially freed by cutting. This freeing by cutting can be carried out, for example, by means of a milling cutter introduced into the interior of the pipeline. The milling head of this milling cutter preferably has a diameter corresponding to the diameter of the pipeline. However, milling heads with a diameter smaller than the diameter of the pipeline can also be used. In such an embodiment, however, care must be taken to ensure that, in the final step, the curable material in the pipeline and, if applicable, the bellows body are milled out to such an extent that there is no narrowing of the inner diameter in this area of the pipeline. As a result of the freeing by cutting, preferably both the cured material, insofar as it is located within the pipeline, and the introduced bellows body should be completely comminuted until the curable material at least still seals the leaky and / or damaged section on the inner wall of the pipeline. Parts of the curable material that have entered the outside area of the pipeline through the leaky section and completely or partially fill cavities located there remain unaffected by the freeing by cutting. After carrying out the method according to the invention, the leaky and / or damaged section on the inner wall of the pipeline is thus completely sealed by the curable material, the area outside the leaky section in the pipeline wall is additionally protected against external influences, and all solids previously present in the area of the pipeline, such as pipe sections, soil, stones, dust, etc., are completely removed from the pipeline. In a preferred embodiment, the inner diameter of the pipeline in the area of the leaky and / or damaged section is substantially equal to an undamaged area of the pipeline after the repair. No edges or leaks form between the area freed by cutting and the other areas of the pipeline, where deposits could form or through which substances from outside could penetrate the pipeline or substances inside the pipeline could escape to the outside. In one embodiment, the curable material is introduced through at least one hose connection from a pump located outside the pipeline into the interior of the pipeline and / or the bellows body, and the hose connection is withdrawn before curing. This prevents the hose connections from being permanently enclosed in the introduced material after curing. The hose connection can thus continue to be used after introduction of the curable material and can in particular be used to introduce the curable material into the area of the leaky and / or damaged section of the pipeline after the bellows body. In one embodiment, the curable material consists of several components that are introduced separately and mixed in situ. It can be provided that for each of the components a separate hose connection is introduced from a pump located outside the pipeline, and the hose connections are withdrawn before the material cures. The use of separate hose connections ensures that the components are only combined with each other inside the pipeline and / or the bellows body, where they react with each other and form the curable material. The separate hose connections prevent the curable material from reacting inside a hose connection and clogging the hose connection. A further aspect of the invention is a spray head suitable for mixing at least two components in situ and then applying them inside the pipeline. The spray head is preferably made of plastic and has at least two inlets through which, for example, hoses can be connected. The spray head further comprises a mixer, which is preferably cylindrical in shape and has a rotary drum with circularly arranged blades supported by a ball bearing on the inside. The spray head can be made in one piece or assembled from at least two parts. Opposite the inlets, the mixture of the components is distributed via a nozzle. The spray head can be used both for the curable material and for a subsequent coating. Compared with previously known metal versions, the spray head has the advantage of being cost-effective and can thus be used as a disposable item, which saves working time and cleaning agents. In one embodiment, a PU material is introduced as the curable material. The PU material can, for example, be a single-component PU material and / or a PU foam. Corresponding materials and foams are known to those skilled in the art from other applications. In an advantageous embodiment, a two-component PU foam is introduced as the PU material. With a two-component PU foam, the components can be fed through two hoses from the storage container of the components into the pipeline and / or the bellows body. In this embodiment, the two components are only mixed in the area in which the PU material is to be introduced into the pipeline or the bellows body. Before the PU material cures, the two hoses are removed from the pipeline again. In one embodiment, an epoxy resin is introduced as the curable material. All synthetic resins that contain epoxy groups and react to form a thermosetting plastic when mixed with a curing agent are considered epoxy resins within the meaning of the invention. After curing, epoxy resins have good mechanical properties and are particularly suitable for sealing pipelines. Furthermore, according to the invention, the curable material is introduced into the interior of the pipeline by means of a pump device located outside the pipeline. Particularly in the case of pipelines in which the leaky and / or damaged section is far away from the access opening of the pipeline, high-performance pump devices are recommended, with which the curable material can be pressed from the storage container through hose connections into the bellows body and / or the area of the leaky and / or damaged section. The pump device ensures that the curable material or its components can be quickly and safely transported to the desired location within the pipeline. After curing of the material, in one embodiment, the entire inner diameter of the pipeline from the bellows body to and including the leaky and / or damaged section can be completely filled and sealed. This is easy to achieve by introducing a sufficient amount of curable material. In one embodiment, the cured material will not completely fill the interior of the pipeline in the area of the leaky and / or damaged section. This has the advantage that during the freeing by cutting of the treated section in a non-straight area of the pipeline, the course of the pipeline can be followed. If the pipeline were completely filled, there would be a risk of cutting proceeding in a straight direction and breaking through the pipeline. In one embodiment, the curable material is introduced into the interior of the pipeline by means of a spray device. Spray devices are particularly suitable for use with PU foam. The curable material can thereby be distributed particularly evenly and with a minimum quantity, which reduces the amount required. For shorter distances between the access opening of the pipeline and the leaky and / or damaged section in the inner wall of the pipeline, an aerosol can may also be used as a spray device, which uses a propellant to transport the curable material through the hose connection to the leaky and / or damaged section inside the pipeline. In a further embodiment, a spray gun is used as the spray device. To increase the efficiency of the spray gun, the spray gun can be operated with compressed air or another compressed gas. The spray gun is connected to a compressor, which introduces the compressed air into the spray gun and transports the curable material through the hose connection to the leaky and / or damaged section inside the pipeline. In one embodiment, the bellows body is a plastic bag. This embodiment is particularly cost-effective. The plastic bag is dimensioned so that it can be easily introduced into the pipeline when empty and seals the pipeline after being filled with a curable material. Plastic bags are lightweight and inexpensive to procure. In addition, they can subsequently be easily removed. In one embodiment, the bellows body is expanded with the curable material. The curable material used for this can be the same as or different from the material used to repair the leaky and / or damaged section. In a further embodiment, the bellows body is expanded with a gas, preferably air, nitrogen or carbon dioxide, and / or a liquid, preferably water. This reduces the requirement for curable material and thus saves costs. In one embodiment, the additional step g) is carried out, g) Applying a coating to the interior of the pipeline in the area of the leaky and / or damaged section. This serves as a subsequent sealing of the treated section, leads to improved durability and protects the pipeline from new impairments. The flow of the material conveyed through the pipeline is also improved. In particular, following the method according to the invention, the pipeline is to be coated in the treated area of the previously leaky and / or damaged section inside the pipeline, which was freed by cutting. In this area, there may still be unevenness on the inner wall of the pipeline. The unevenness can be compensated for by the coating, so that a uniform inner wall of the pipeline is restored. In one embodiment, in step g), a coating of a curable resin is applied and subsequently cured. The resin is applied in liquid form to the inner wall of the pipeline. It cures there and then forms a smooth and uniform inner wall of the pipeline. When the resin cures, a hard and durable coating forms on the inside of the pipeline. In a preferred embodiment, the coating is applied with at least one rotating brush head. In this embodiment, the brush head is coated with a coating material. When this brush head is then moved through the pipeline, the coating material is applied evenly to the inner wall of the pipeline by the rotating brush head. In another method, the coating is applied with a spray device. The coating material is applied to the inner wall of the pipeline via this spray device. When the spray device is moved through the pipeline, an even application of the coating material to the inner wall of the pipeline is achieved. In one embodiment, in step g), a fabric hose impregnated with a curable resin is introduced and subsequently cured. The resin-impregnated hose is made of either felt or polyester fabric. This resin-impregnated hose adheres to the inner wall of the pipeline. After it has cured, the hose forms the inner wall of the pipeline. The cured hose forms an even more durable coating of the leaky and / or damaged section. The fabric hose can be introduced into the pipeline using an inversion drum. The inversion drum is a pressure vessel that builds up sufficient pressure to pull the resin-impregnated hose into the pipeline. In one embodiment, in step d) or g), an agent is introduced into the bellows body and / or the pipeline that accelerates and / or improves the curing of the material and / or resin. The hose connection can, for example, consist of a heating hose through which the curable material is heated and its reaction accelerated. Alternatively, air or water can also be introduced into the curable material via the hose connection if the curable material reacts faster and better with air or water. A lamp can also be introduced that emits light of a specific wavelength if the curable material reacts faster and better in this way. In a further embodiment of the method according to the invention, the pipeline is flushed with water after freeing the cured material and the bellows body by cutting, in order to transport the cut material out of the pipeline. When freeing the pipeline by cutting, the cured material and, if applicable, the bellows body are comminuted. The resulting cut material then settles on the bottom of a horizontal pipeline or at the next bend in a vertical or inclined pipeline. To prevent the cut material from clogging the pipeline, a gas, preferably air, nitrogen or carbon dioxide, or a liquid, preferably water, is introduced into the pipeline under pressure so that the cut material is transported from its place of deposition in the pipeline further along. In another embodiment of the method according to the invention, the cut material is sucked out of the pipeline by means of negative pressure. In this method, the cut material is not transported further along the pipeline, as in the above method, but is sucked out through the access opening to the pipeline. This method has the advantage that no cut material remains in the pipeline and thus deposits and / or blockages further along the pipeline are avoided. In a further embodiment of the method according to the invention, before positioning the bellows body, a mobile camera is first inserted into the pipeline in order to examine the interior of the pipeline and to locate leaky and / or damaged sections on the inner wall of the pipeline. The mobile camera is used to examine the interior of the pipeline to determine where leaks and / or damage to the inner wall of the pipeline are present. In this way, it can be determined exactly where the bellows body is to be positioned within the pipeline and where the inner wall of the pipeline is to be repaired using the method according to the invention. After introducing the curable material, the camera can be used to check whether sufficient material has been introduced. The invention further relates to a set of parts (kit of parts) for carrying out a method according to the invention. The set of parts comprises at least a bellows body insertable into a pipeline, a pump for introducing a curable material into the bellows body, and a curable material insertable into the bellows body. The set of parts can further comprise a protective cap for the bellows body. According to a further embodiment of the invention, the set of parts comprises a spray head suitable for mixing at least two components in situ and then applying them inside a pipeline.

Claims

1. Method for repairing a leaky and / or damaged section of a pipeline, comprising the following steps:a)    Providing a bellows bodyb)     Positioning the bellows body in the interior of the pipelineadjacent to the leaky and / or damaged sectionc)    Expanding the bellows body until the bellows body seals thepipelined)     Introducing a curable material into the interior of the pipeline inthe area of the leaky and / or damaged sectione)    Curing the curable materialf)     At least partially freeing the interior of the pipeline2. Method according to claim 1, characterised in that the curable material consists of several components that are introduced separately and mixed in situ.

3. Method according to any one of the preceding claims, characterised in that a PU material is introduced as the curable material.

4. Method according to claim 3, characterised in that a two-component PU foam is introduced as the PU material.

5. Method according to any one of the preceding claims, characterised in that an epoxy resin is introduced as the curable material.

6. Method according to any one of the preceding claims, characterised in that the cured material does not completely fill the interior of the pipeline in the area of the leaky and / or damaged section.

7. Method according to any one of the preceding claims, characterised in that the inner diameter of the pipeline in the area of the leaky and / or damaged section is substantially equal to an undamaged area of the pipeline after the repair.

8. Method according to any one of the preceding claims, characterised in that the curable material is introduced into the interior of the pipeline by means of a spray device.

9. Method according to any one of the preceding claims, characterised in that the bellows body is a plastic bag.

10. Method according to any one of the preceding claims, characterised in that the bellows body is expanded with the curable material.

11. Method according to any one of the preceding claims, characterised in that the bellows body is expanded with a gas, preferably air, nitrogen or carbon dioxide, and / or a liquid, preferably water.

12. Method according to any one of the preceding claims, characterised in that the additional step g) is carried out,g) Applying a coating to the interior of the pipeline in the area of the leaky and / or damaged section.

13. Method according to claim 10, characterised in that in step g) a coating of a curable resin is applied and subsequently cured.

14. Method according to claim 10 or 11, characterised in that in step g) a fabric hose impregnated with a curable resin is introduced and subsequently cured.

15. Method according to any one of the preceding claims, characterised in that in step d) or g) an agent is introduced into the bellows body and / or the pipeline that accelerates and / or improves the curing of the material and / or resin.

16. Set of parts for carrying out a method according to any one of claims 1 to 15, comprising at least a bellows body insertable into a pipeline, a pump for introducing a curable material into the bellows body, and a curable material insertable into the bellows body.

17. Set of parts according to claim 16, further comprising a protective cap for the bellows body.

18. Set of parts according to claim 16 or 17, further comprising a spray head suitable for mixing at least two components in situ and then applying them inside a pipeline.