U-pressing penetrating repair device and repair method for large pipeline

Abstract

The invention relates to the technical field of pipeline insertion repair, and provides a large pipeline U-pressing insertion repair device and method, the large pipeline U-pressing insertion repair device can be matched with a to-be-repaired pipeline to complete insertion repair operation, an insertion pipeline for insertion adopts a pretreatment mode, and construction operation can be carried out outside the to-be-repaired pipeline; the pipeline repairing device effectively reduces limitation of construction space, enables construction operation to be more convenient and easy to implement, comprises a to-be-repaired pipeline, and further comprises an insertion pipeline, a traction assembly and a pipeline pressing assembly, the insertion pipeline is used for forming insertion repairing in the to-be-repaired pipeline, the traction assembly comprises two traction plate frames, and the two traction plate frames are both fixedly connected with the insertion pipeline; and the pipeline shape pressing assembly comprises a main body frame, a downward pressing hydraulic cylinder, a plurality of supporting rollers, a plurality of first side pushing rollers and a plurality of second side pushing rollers, the supporting rollers are all rotationally installed in the main body frame, an adjusting mechanism is installed in the main body frame, and the first side pushing rollers and the second side pushing rollers are all installed in the adjusting mechanism.

Description

Technical Field

[0001] This invention relates to the field of pipeline penetration repair technology, specifically to a large-scale pipeline U-shaped penetration repair device and repair method. Background Technology

[0002] As is well known, the "U-shaped insertion method" is a trenchless repair technology that uses a special diameter reduction device to press HDPE pipes into a U-shaped cross section, then pulls them into the old pipe to be repaired. After insertion, the pipes automatically return to a round shape and fit together due to the elasticity of the material. To facilitate U-shaped pipe pressing operations, we propose a large-scale U-shaped insertion repair device and repair method, which can reduce the cross section of the inserted pipe by about 40% after pressing it into a U-shape.

[0003] A search revealed that Chinese patent application number CN201810825884.2 discloses a pipe counter-pull repair device and its repair method. The device generally includes a first repair device and a second repair device, located at opposite ends of the pipe to be repaired. The first and second repair devices move towards each other and are connected by a counter-pull device. In use, a pull rod is inserted into the pipe to be repaired, and the first and second repair devices are placed into working wells on both sides of the pipe. Simultaneously, a first and second cutting tool disc unit are installed into the pipe. The two ends of the pull rod are detachably fixed to a first top plate and a second clamping plate. The steel mold is then... Do not place it at the first and second clamping plates. Start the hydraulic cylinder, the piston rod extends, the cylinder body drives the first clamping plate to move to the right, the first clamping plate drives the steel mold to move to the right, the steel mold pushes the first push cutter head unit to move to the right to cut the pipe to be repaired, the piston rod drives the top plate and pull rod to move to the left, the pull rod drives the second clamping plate to move to the left, the second clamping plate pushes the steel mold and the second push cutter head unit to move to the left. When the steel mold is fully pushed in, the piston rod returns to its original position, that is, the top plate drives the pull rod and the second clamping plate to move to the right, and prepares to place the next steel mold at the first and second clamping plates. Repeat the above steps until the first push cutter head unit and the second push cutter head unit meet, close the first and second push cutter head units, and pull out the first and second push cutter head units.

[0004] While the aforementioned existing technical solutions can achieve pipeline repair operations, their core construction operations are all carried out inside the pipeline to be repaired. The construction process is constrained by the inner diameter of the pipeline, and the construction space is extremely limited. This not only makes the pipeline repair operation quite limited, but also leads to high construction difficulty. Therefore, the pipeline repair has significant limitations, and the construction difficulty coefficient needs to be further reduced. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a large-scale pipeline U-shaped insertion repair device and repair method, which can be used in conjunction with the pipeline to be repaired to complete the insertion repair operation. Moreover, the insertion pipeline used for insertion adopts a pre-treated mode, which enables construction work to be carried out outside the pipeline to be repaired, effectively reducing the limitation of construction space and making the construction operation more convenient and easy.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a large-scale pipe U-shaped insertion repair device, comprising a pipe to be repaired, an insertion pipe, a traction assembly, and a pipe forming assembly. The insertion pipe is used to form an insertion repair within the pipe to be repaired. The traction assembly includes two traction plates, both of which are fixedly connected to the insertion pipe. The pipe forming assembly includes a main frame, a downward hydraulic cylinder, multiple support rollers, multiple first side push rollers, and multiple second side push rollers. The multiple support rollers are rotatably installed within the main frame. An adjustment mechanism is installed within the main frame. The multiple first side push rollers and multiple second side push rollers are installed within the adjustment mechanism. The downward hydraulic cylinder is installed on the main frame, and a lifting wheel frame is installed on the lifting column of the downward hydraulic cylinder. A deformable pressure roller is rotatably connected within the lifting wheel frame. An attitude extension and holding structure is installed on the main frame. The attitude extension and holding structure is used for the attitude extension of the inserted pipe after the deformable pressure roller has pressed it U-shaped. A winding mechanism is installed at the front end of the main frame. The winding mechanism is used for maintaining the shape of the inserted pipe after it has been pressed U-shaped.

[0007] Preferably, the winding mechanism includes a fixed track ring and a rotating mounting ring. The fixed track ring is fixedly connected to the front end of the main frame, and the rotating mounting ring is rotatably connected to the fixed track ring. A first servo motor is mounted on the rotating mounting ring, which drives the rotation of the rotating mounting ring relative to the fixed track ring. A fixed shaft is fixedly connected to the rotating mounting ring, and a rope take-up frame is rotatably mounted on the fixed shaft. A binding rope is provided on the rope take-up frame, and a guide plate is provided at the front end of the rope take-up frame. The guide plate has an opening groove for guiding the binding rope through, and a through hole is provided in the opening groove. A limit bolt is provided in the through hole. A second servo motor is mounted on the rotating mounting ring, which drives the rotation of the rope take-up frame.

[0008] Preferably, the posture extension and holding structure includes a lifting hydraulic cylinder, which is mounted on the main frame. An extension cylinder is fixedly connected to the bottom end of the lifting column of the lifting hydraulic cylinder. A vertical end cylinder is fixedly connected to the end of the extension cylinder near the deforming pressure roller, and an inclined end cylinder is fixedly connected to the end of the extension cylinder away from the deforming pressure roller.

[0009] Preferably, the main frame is fixedly connected to a rope feeding frame, a rope feeding roller is rotatably connected inside the rope feeding frame, a third servo motor is installed outside the rope feeding frame, the servo shaft of the third servo motor is drivenly connected to the rope feeding frame, a pulling rope is provided on the rope feeding roller, and the pulling rope passes through the vertical end cylinder, the extension cylinder and the inclined end cylinder in sequence.

[0010] Preferably, two central guide cylinders and two side guide cylinders are fixedly connected within the main frame. A central guide column is slidably connected within each of the two central guide cylinders. The two central guide columns are fixedly connected to the vertical end cylinder and the inclined end cylinder, respectively. A side guide column is slidably connected within each of the two side guide cylinders. A tripod is fixedly connected to the lifting wheel frame. The two side guide columns are fixedly connected to the tripod.

[0011] Preferably, the adjusting mechanism includes a lifting hydraulic cylinder, two upper guide columns, and two lower guide columns. The lifting hydraulic cylinder is mounted on the main frame. The two upper guide columns and two lower guide columns are fixedly connected within the main frame. Each of the two upper guide columns is slidably connected to a first pair of shifting frames and a second pair of shifting frames. The two first pairs of shifting frames are slidably connected to the two lower guide columns, and the two second pairs of shifting frames are slidably connected to the two lower guide columns. A first lifting frame is slidably connected between the two first pairs of shifting frames, and a second lifting frame is slidably connected between the two second pairs of shifting frames. A synchronous frame is fixedly connected to the lifting column of the lifting hydraulic cylinder. The first and second lifting frames are both fixedly connected to the synchronous frame. A first mounting frame is slidably connected to the first lifting frame. Multiple first side push rollers are rotatably connected to the first mounting frame. A second mounting frame is slidably connected to the second mounting frame. Multiple second side push rollers are rotatably connected to the second mounting frame. Side push hydraulic cylinders are connected to both the first and second mounting frames. The two side push hydraulic cylinders are respectively connected to the first and second lifting frames.

[0012] Preferably, a plurality of first side supports and second side supports are fixedly connected within the main frame, and a plurality of support rollers are rotatably connected to a plurality of first side supports and a plurality of support rollers are rotatably connected to a plurality of second side supports. Each of the plurality of support rollers is provided with a gradient annular groove, which is used for centering support and limiting of the inserted pipe.

[0013] Preferably, both traction plate frames are provided with multiple fixing holes, and side-mounted bolts are provided in each of the multiple fixing holes. The end of the insertion pipe is provided with an insertion hole, and the multiple insertion holes are respectively matched with the multiple side-mounted bolts. Both traction plate frames are provided with traction holes and auxiliary mounting holes. The traction holes are used for auxiliary pulling of the traction plate frames, and the auxiliary mounting holes are used for auxiliary connection and positioning of the binding rope. Both traction plate frames are provided with inner lining plates, and both inner lining plates are provided with connecting holes. The multiple connecting holes are respectively used for the multiple side-mounted bolts to pass through.

[0014] Preferably, hoisting rings are provided at the top four corners of the main frame.

[0015] A method for repairing U-shaped pipes with pressure penetration includes the following steps: S1. First, the main frame is placed and installed stably to provide a foundation for subsequent pressing and insertion operations. Then, the lateral distance between the first and second side push rollers is adjusted by the adjustment mechanism to adapt to the specifications of the insertion pipe. Next, two traction plate frames are installed relative to the insertion pipe, and both traction plate frames are connected to the external traction power equipment. S2. Through the smooth traction of the traction component, the insertion pipe passes through the main frame from back to front. As the insertion pipe enters from the rear side of the main frame, it is smoothly transported into the main frame and placed on multiple support rollers. The lowering hydraulic cylinder is activated, and the lifting wheel frame is driven to lower its height through the lowering hydraulic cylinder, so that the deformation pressure roller moves downward to apply pressure to the insertion pipe and drive the insertion pipe to form a U-shaped deformation process. S3. As the lifting wheel frame applies pressure to the upper side of the insertion pipe, the adjustment mechanism works in conjunction to adjust the relative position of the first side push roller and the second side push roller, applying lateral pressure to the insertion pipe, so that the insertion pipe is pressed into a complete U-shaped structure under the coordinated limiting and squeezing action of the deformation pressure roller, support roller, first side push roller and second side push roller. S4. After the deformation pressure roller completes the U-shaped pressing operation on the inserted pipe, the posture extension and holding structure constrains the posture of the U-shaped inserted pipe, effectively preventing the inserted pipe from rebounding and resetting due to its own elasticity, so that the inserted pipe can maintain a stable U-shaped shape. At the same time, the winding mechanism at the front end of the main frame is activated to wind and bind the U-shaped inserted pipe, further enhancing its shape stability after pressing and reducing structural deformation during the insertion process. S5. By continuing to pull the two traction plates, the U-shaped insertion pipe after being wrapped and reinforced is aligned with the pipe to be repaired and moves along the pipe to be repaired at a constant speed, ensuring that the insertion pipe maintains its U-shaped structure and passes smoothly through the pipe to be repaired throughout the process, until the insertion pipe is completely inserted through the pipe to be repaired. After the insertion is completed, the wrapping constraint on the insertion pipe is released, so that the insertion pipe restores its original circular structure and forms a fit with the inner wall of the pipe to be repaired, thus completing the construction of the large pipe U-shaped insertion repair.

[0016] Compared with the prior art, the present invention provides a large-scale pipeline U-shaped interlocking repair device and method, which has the following beneficial effects: (1). In this invention, the design of the traction component can be matched with the pipe to form an auxiliary installation, which can not only provide an auxiliary traction force point for the inserted pipe, but also cooperate with the binding rope in the winding mechanism to achieve auxiliary connection and positioning.

[0017] (2). In this invention, the design of the pipe forming component enables the insertion of a pipe to achieve auxiliary U-forming drive, and the U-forming amplitude is adjustable, making it more practical.

[0018] (3). In this invention, through the design of the adjustment mechanism, multiple first side push rollers and multiple second side push rollers can be matched to form an auxiliary installation in the main frame. At the same time, it is convenient to make auxiliary adjustments to the first side push rollers and the second side push rollers. It can cooperate with the lifting wheel frame to squeeze the outside of the inserted pipe, effectively improving the U-shaped effect of the inserted pipe.

[0019] (4). In this invention, the posture extension and holding structure is designed to maintain the posture of the area on the pipe after being pressed by the lifting wheel frame, so as to ensure that the inserted pipe maintains the pressed U-shaped posture and smoothly enters the working area of ​​the winding mechanism.

[0020] (5). In this invention, the design of the winding mechanism can be matched with the inserted pipe after pressing to form an auxiliary winding operation, ensuring that the inserted pipe maintains the pressed U-shaped state and penetrates into the inside of the pipe to be repaired. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural diagram of the entire invention; Figure 2 For the present invention Figure 1 A magnified schematic diagram of the local structure at point A; Figure 3 For the present invention Figure 1 A magnified schematic diagram of the local structure at point B; Figure 4 This is a three-dimensional structural diagram of the present invention, showing the cooperation of the insertion pipe, traction plate frame, and binding rope, etc. Figure 5 This is a three-dimensional structural diagram of the inserted pipe of the present invention in the state of interpenetration with the pipe to be repaired; Figure 6 This is a three-dimensional structural diagram of the main frame, support rollers, and fixed track ring of the present invention. Figure 7 This is a three-dimensional structural diagram of the entire invention from another angle; Figure 8 For the present invention Figure 7 A magnified schematic diagram of the structure at point C in the middle; Figure 9 For the present invention Figure 7 A magnified schematic diagram of the local structure at point D; Figure 10 This is a three-dimensional structural diagram of the main frame, the first side support, and the second side support of the present invention. Figure 11This is a three-dimensional structural diagram of the inserted pipe relative to the pipe to be repaired, from another angle. Figure 12 This is a bottom-view three-dimensional structural diagram of the main frame, support rollers, and fixed track ring of the present invention. Figure 13 For the present invention Figure 12 A magnified schematic diagram of the local structure at point E; Figure 14 This is an exploded three-dimensional structural diagram of the first lifting frame, the first mounting frame, and the side-push hydraulic cylinder of the present invention. Figure 15 This is an exploded three-dimensional structural diagram of the fixed shaft, guide plate, and clamping bolts of the present invention. Figure 16 This is a bottom-view three-dimensional structural diagram of the present invention, showing the insertion of the pipe, the traction plate frame, and the binding rope.

[0022] In the diagram: 1. Pipe to be repaired; 2. Inserted pipe; 3. Traction plate frame; 4. Main frame; 5. Downward hydraulic cylinder; 6. Support roller; 7. First side push roller; 8. Second side push roller; 9. Lifting wheel frame; 10. Deformable pressure roller; 11. Fixed track ring; 12. Rotating mounting ring; 13. First servo motor; 14. Fixed shaft; 15. Rope take-up frame; 16. Binding rope; 17. Guide plate; 18. Opening slot; 19. Through hole; 20. Limit bolt; 21. Second servo motor; 22. Lifting hydraulic cylinder; 23. Extension cylinder; 24. Vertical end cylinder; 25. Slanted end cylinder; 26. Rope release frame; 27. Rope release roller; 28. Third servo motor; 29. 30. Pull rope; 31. Middle guide cylinder; 32. Side guide cylinder; 33. Middle guide column; 34. Side guide column; 35. Tripod; 36. Lifting hydraulic cylinder; 37. Upper guide column; 38. Lower guide column; 39. First pair of moving frames; 40. Second pair of moving frames; 41. First lifting frame; 42. Second lifting frame; 43. Synchronous frame; 44. First mounting frame; 45. Second mounting frame; 46. Side push hydraulic cylinder; 47. First side support; 48. Second side support; 49. Gradient annular groove; 50. Fixing hole; 51. Side mounting bolt; 52. Insertion hole; 53. Traction hole; 54. Auxiliary mounting hole; 55. Inner liner plate; 56. Connecting hole; 57. Lifting ring. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] For examples, please refer to Figures 1-16A large-scale pipe compression and insertion repair device includes a pipe to be repaired (1), an insertion pipe (2), a traction assembly, and a pipe compression assembly. The insertion pipe (2) is used to insert and repair the pipe into the pipe to be repaired (1). The traction assembly includes two traction plates (3), both of which are fixedly connected to the insertion pipe (2). Each traction plate (3) has multiple fixing holes (49), and each fixing hole (49) contains a side-mounted bolt (50). The end of the insertion pipe (2) has an insertion hole (51), which matches the side-mounted bolt (50). Each traction plate (3) has a traction hole (52) and an auxiliary mounting hole (53). The traction hole (52) is used for auxiliary pulling of the traction plate (3), and the auxiliary mounting hole (53) is used for auxiliary connection and positioning of the binding rope (16). Each of the three components is equipped with an inner lining plate 54, and each inner lining plate 54 is provided with a connecting hole 55. Multiple connecting holes 55 are used for multiple side-mounted bolts 50 to pass through. Through the design of the traction component, it can be used to insert the pipe 2 to form an auxiliary installation. It can provide an auxiliary traction force point for the inserted pipe 2 and cooperate with the binding rope 16 in the winding mechanism to achieve auxiliary connection and positioning. The pipe forming component includes a main frame 4, a pressing hydraulic cylinder 5, multiple support rollers 6, multiple first side push rollers 7 and multiple second side push rollers 8. Multiple support rollers 6 are rotatably installed in the main frame 4. Multiple first side supports 46 and second side supports 47 are fixedly connected in the main frame 4. Multiple support rollers 6 are rotatably connected to multiple first side supports 46 and multiple second side supports 47 respectively. Multiple support rollers 6 are rotatably connected to multiple first side supports 46 respectively and multiple second side supports 47 respectively. The side support 47 is rotatably connected. Multiple support rollers 6 are each provided with a gradient annular groove 48, which is used for centering and limiting the insertion of the pipe 2. An adjustment mechanism is installed inside the main frame 4. Multiple first side push rollers 7 and multiple second side push rollers 8 are installed within the adjustment mechanism. The adjustment mechanism includes a lifting hydraulic cylinder 35, two upper guide columns 36, and two lower guide columns 37. The lifting hydraulic cylinder 35 is installed on the main frame 4. The two upper guide columns 36 and two lower guide columns 37 are fixedly connected inside the main frame 4. Each of the two upper guide columns 36 is slidably connected to a first pair of shifting frames 38 and a second pair of shifting frames 39. The two first pairs of shifting frames 38 are slidably connected to the two lower guide columns 37, and the two second pairs of shifting frames 39 are slidably connected to the two lower guide columns 37, respectively. A first lifting frame 40 is slidably connected between two first pairs of moving frames 38, and a second lifting frame 41 is slidably connected between two second pairs of moving frames 39. A synchronous frame 42 is fixedly connected to the lifting column of the lifting hydraulic cylinder 35. Both the first lifting frame 40 and the second lifting frame 41 are fixedly connected to the synchronous frame 42. A first mounting frame 43 is slidably connected to the first lifting frame 40, and multiple first side push rollers 7 are rotatably connected to the first mounting frame 43. A second mounting frame 41 is slidably connected to the second mounting frame 44, and multiple second side push rollers 8 are rotatably connected to the second mounting frame 44. Side push hydraulic cylinders 45 are connected to both the first mounting frame 43 and the second mounting frame 44. The two side push hydraulic cylinders 45 are respectively connected to the first lifting frame 40 and the second lifting frame 41. This is achieved through the design of the adjusting mechanism.Multiple first-side push rollers 7 and multiple second-side push rollers 8 can be installed within the main frame 4 to form an auxiliary assembly. This facilitates auxiliary adjustment of the first-side push rollers 7 and second-side push rollers 8. It can cooperate with the lifting wheel frame 9 to apply pressure to the outer side of the inserted pipe 2, effectively improving the U-shaped forming effect of the inserted pipe 2. The lowering hydraulic cylinder 5 is mounted on the main frame 4, and the lifting column of the lowering hydraulic cylinder 5 is equipped with the lifting wheel frame 9. A deformable pressure roller 10 is rotatably connected inside the lifting wheel frame 9. Through the design of the pipe forming assembly, it can be used to assist in the U-shaped forming drive of the inserted pipe 2, and the U-shaped forming amplitude is adjustable, making it more practical.

[0025] It should be further explained that a posture extension and retention structure is installed on the main frame 4. This structure is used for posture shaping and extension of the inserted pipe 2 after being pressed U-shaped by the deformation roller 10. The posture extension and retention structure includes a lifting hydraulic cylinder 22, which is installed on the main frame 4. An extension cylinder 23 is fixedly connected to the bottom end of the lifting column of the lifting hydraulic cylinder 22. A vertical end cylinder 24 is fixedly connected to the end of the extension cylinder 23 near the deformation roller 10, and an inclined end cylinder 25 is fixedly connected to the end of the extension cylinder 23 away from the deformation roller 10. Through the design of the posture extension and retention structure, the posture of the area on the inserted pipe 2 after being pressed U-shaped by the lifting roller frame 9 can be maintained, ensuring that the inserted pipe 2 maintains a U-shaped posture and smoothly enters the winding mechanism. In the area, a winding mechanism is installed at the front end of the main frame 4. The winding mechanism is used to maintain the shape of the pipe 2 after it is inserted and pressed. The winding mechanism includes a fixed track ring 11 and a rotating mounting ring 12. The fixed track ring 11 is fixedly connected to the front end of the main frame 4. The rotating mounting ring 12 is rotatably connected to the fixed track ring 11. A first servo motor 13 is installed on the rotating mounting ring 12. The first servo motor 13 is used to drive the rotation of the rotating mounting ring 12 relative to the fixed track ring 11. A fixed shaft 14 is fixedly connected to the rotating mounting ring 12. A rope take-up frame 15 is rotatably mounted on the fixed shaft 14. A binding rope 16 is provided on the rope take-up frame 15. A guide plate 17 is provided at the front end of the rope take-up frame 15. A prismatic cylinder is fixedly connected to the front end of the rope take-up frame 15. The guide plate 17 is provided with a prismatic hole that matches the prismatic cylinder. The prismatic cylinder is threadedly connected to a clamping bolt. A straight plate is fitted on the clamping bolt. The straight plate is used to clamp and limit the guide plate 17 relative to the prismatic cylinder. The guide plate 17 is provided with an opening groove 18 for guiding the binding rope 16 through. A through hole 19 is provided in the opening groove 18, and a limit bolt 20 is provided in the through hole 19. A second servo motor 21 is installed on the rotating mounting ring 12. The second servo motor 21 is used to drive the rotation of the rope winding frame 15. Through the design of the winding mechanism, it can be matched with the U-shaped insertion pipe 2 to form an auxiliary winding operation, ensuring that the insertion pipe 2 maintains the U-shaped state and is inserted into the interior of the pipe 1 to be repaired. The main frame 4 is fixedly connected to a release... A rope frame 26 has a rope release roller 27 rotatably connected inside it. A third servo motor 28 is mounted outside the rope release frame 26, and its servo shaft is connected to the rope release frame 26 for transmission. A pull rope 29 is provided on the rope release roller 27. The pull rope 29 passes sequentially through the vertical end cylinder 24, the extension cylinder 23, and the inclined end cylinder 25, accompanying the insertion pipe 2 as it passes through the main body frame 4. The pull rope 29 is placed in the pressure U area inside the insertion pipe 2 to assist in the subsequent traction and removal of the binding rope 16 relative to the insertion pipe 2. Two central guide cylinders 30 and two side guide cylinders 31 are fixedly connected inside the main body frame 4. A central guide post 32 is slidably connected inside each of the two central guide cylinders 30. The two central guide posts 32 are fixedly connected to the vertical end cylinder 24 and the inclined end cylinder 25, respectively.To enhance the stability of the lifting direction of the overall structure formed by the extension cylinder 23, the vertical end cylinder 24, and the inclined end cylinder 25, ensuring the structural stability and directional accuracy of the U-shaped area after the inserted pipe 2 is pressed into the U, side guide columns 33 are slidably connected inside both side guide cylinders 31, and a tripod 34 is fixedly connected to the lifting wheel frame 9. Both side guide columns 33 are fixedly connected to the tripod 34, improving the trajectory stability of the lifting wheel frame 9 during the lifting process and reducing the positional offset caused by the reaction force of the inserted pipe 2 when the deformable pressure roller 10 acts on the inserted pipe 2. Lifting rings 56 are provided at the four corners of the top of the main frame 4. By installing lifting straps at the lifting rings 56, the overall lifting and transportation of the main frame 4 is facilitated.

[0026] A method for U-shaped insertion repair of large pipes includes the following steps: First, the main frame 4 is stably placed and installed to provide a foundation for subsequent pressing and insertion operations. Then, the lateral distance between the first side push roller 7 and the second side push roller 8 is adjusted by an adjustment mechanism to adapt to the specifications of the inserted pipe 2. Next, two traction plates 3 are installed relative to the inserted pipe 2, and both traction plates 3 are connected to external traction power equipment. Through the smooth traction action of the traction components, the inserted pipe 2 passes through the main frame 4 from back to front. As the inserted pipe 2 enters from the rear side of the main frame 4, it is smoothly transported into the interior of the main frame 4 and placed on multiple support rollers 6. The lowering hydraulic cylinder 5 is activated, which drives the lifting wheel frame 9 to lower its height, causing the deformation pressure roller 10 to move downward to apply pressure to the inserted pipe 2, driving the inserted pipe 2 to form a U-shaped deformation. As the lifting wheel frame 9 applies pressure to the upper side of the inserted pipe 2, the adjustment mechanism is used to adjust the relative position of the first side push roller 7 and the second side push roller 8, applying lateral pressure to the inserted pipe 2, causing the inserted pipe 2 to... Under the coordinated limiting and squeezing action of the deformation pressure roller 10, support roller 6, first side push roller 7 and second side push roller 8, a complete U-shaped structure is formed. After the deformation pressure roller 10 completes the U-shaped pressing operation on the inserted pipe 2, the posture extension and holding structure constrains the posture of the U-shaped inserted pipe 2, effectively preventing the inserted pipe 2 from rebounding and resetting due to its own elasticity, so that the inserted pipe 2 maintains a stable U-shaped shape. At the same time, the winding mechanism at the front end of the main frame 4 is activated to wind and bind the U-shaped inserted pipe 2, further enhancing its post-pressed U-shaped shape stability and reducing structural deformation during insertion. By continuing to pull the two traction plates 3, the wound and reinforced U-shaped inserted pipe 2 is aligned with the pipe 1 to be repaired and passes through the pipe 1 at a uniform speed, ensuring that the inserted pipe 2 maintains a U-shaped structure throughout the process and passes through the pipe 1 to be repaired smoothly until the inserted pipe 2 completely passes through the pipe 1 to be repaired. After the insertion is completed, the winding constraint on the inserted pipe 2 is released, so that the inserted pipe 2 restores its original circular structure and forms a fit with the inner wall of the pipe 1 to be repaired, thus completing the construction of the large pipe U-shaped insertion repair.

[0027] In this embodiment, the downward hydraulic cylinder 5, the lifting hydraulic cylinder 22, the hoisting hydraulic cylinder 35, the side-pushing hydraulic cylinder 45, the first servo motor 13, the second servo motor 21, and the third servo motor 28 are all commercially available conventional devices known to those skilled in the art. Other models can be selected or customized according to actual needs. In this invention, we only use them without improving their structure and function. Their setting method, installation method, and electrical connection method can be easily understood by those skilled in the art by following the instructions for use. Therefore, they will not be described in detail here.

[0028] In summary, the working principle of this large-scale pipeline U-shaped insertion repair device is as follows: Before use, the construction site is first leveled to facilitate the stable placement of the main frame 4. Then, the entire device is hoisted and transported using the hoisting ring 56 and hoisting equipment, ensuring that the main frame 4 is stably placed and installed at the corresponding construction position. Next, the electrical components of the device are wired, and the hydraulic components are connected to the oil supply. The first servo motor 13, the second servo motor 21, and the third servo motor 28 are then tested under no-load conditions. Simultaneously, the downward hydraulic cylinder 5, the lifting hydraulic cylinder 22, the hoisting hydraulic cylinder 35, and the side-push hydraulic cylinder 45 are also tested under no-load conditions to ensure their normal operation, facilitating subsequent operation. Finally, the hoisting hydraulic cylinder 35 is activated, driving the synchronous frame 42 through its lifting column. Vertical displacement adjustment: The synchronous frame 42 synchronously drives the first lifting frame 40 and the second lifting frame 41 to move. The movement of the first lifting frame 40 and the second lifting frame 41 respectively drives the first mounting frame 43 and the second mounting frame 44 to adjust their height, thereby achieving the overall height adjustment of the first side push roller 7 and the second side push roller 8. At the same time, the side push hydraulic cylinders 45 on both sides extend in stages, respectively pushing the first mounting frame 43 and the second mounting frame 44 to slide laterally relative to the first lifting frame 40 and the second lifting frame 41, thereby driving the first side push roller 7 and the second side push roller 8 to complete the adjustment of the lateral spacing, so that the space between the first side push roller 7 and the second side push roller 8 is adapted to the outer diameter specification of the insertion pipe 2. The gradient annular grooves 48 opened on the surface of each support roller 6 can provide continuous centering support and guide limit for the inserted pipe 2, reducing the left and right sway and axial twist of the inserted pipe 2 during the conveying process, and ensuring that the inserted pipe 2 always moves stably along the central axis of the main frame 4.

[0029] After completing the forming mechanism debugging, the traction assembly is assembled. Both traction plate frames 3 are fitted onto the same end of the insertion pipe 2. Then, according to the position of the fixing hole 49 on the traction plate frame 3, insertion holes 51 are pre-drilled on the insertion pipe 2. An inner liner plate 54 is placed into the insertion pipe 2 in conjunction with the traction plate frame 3, ensuring the inner liner plate 54 is tightly fitted against the inner wall of the insertion pipe 2 and matches the traction plate frame 3. Multiple side-mounted bolts 50 are sequentially passed through the fixing hole 49, insertion hole 51, and connecting hole 55, and nuts are screwed into the threaded ends of the side-mounted bolts 50 to achieve fixed installation of the traction plate frame 3 relative to the insertion pipe 2. Then, the other traction assembly is completed. After the installation of the guide plate frame 3 relative to the insertion pipe 2, the traction hole 52 on the guide plate frame 3 is connected to an external power equipment such as a winch or traction hoist. During the connection process, the corresponding traction rope in the winch or traction hoist should pass through the main frame 4 from back to front. After the preparation and inspection are completed, the external traction power equipment is started, and a steady axial traction force is applied to the insertion pipe 2 through the guide plate frame 3, so that the insertion pipe 2 moves forward at a constant speed from the rear side of the main frame 4. During this process, the bottom of the insertion pipe 2 will sequentially enter multiple support rollers 6 to ensure that the insertion pipe 2 can always be stably erected on multiple gradient rings. Within the groove 48, the support roller 6 rotates freely as the insertion pipe 2 moves forward to reduce conveying friction resistance. When the front end of the insertion pipe 2 reaches directly below the deforming pressure roller 10, it enters a traction pause state and activates the downward pressure hydraulic cylinder 5. The downward pressure hydraulic cylinder 5 drives the lifting column downward through a staged pressurization method. The lifting column drives the lifting wheel frame 9 to move vertically downward. Through the triangular frame 34, it forms an auxiliary guiding cooperation with the side guide columns 33 and side guide cylinders 31 on both sides to ensure that the deforming pressure roller 10 maintains a vertical downward pressing trajectory, reducing lateral offset and tilting sway. After the deforming pressure roller 10 falls and contacts the front end of the insertion pipe 2 and is pressed and deformed in place, The traction movement of the inserted pipe 2 is restored. At the same time, the adjustment mechanism enters the coordinated operation state. The hydraulic cylinder 35 is lifted to finely adjust the vertical height of the first side push roller 7 and the second side push roller 8 in real time. The side push hydraulic cylinders 45 on both sides apply pressure in stages, so that the first side push roller 7 and the second side push roller 8 apply symmetrical lateral extrusion force to the inserted pipe 2 from the left and right sides. With the stable lifting and limiting of multiple support rollers 6 at the bottom, the deformation pressure roller 10, support roller 6, first side push roller 7 and second side push roller 8 form a four-way encircling coordinated extrusion action, which gradually, evenly and continuously presses the circular cross-section inserted pipe 2 into a U-shaped structure with a reduced cross-section.

[0030] As the insertion pipe 2 moves relative to the main frame 4, after the insertion pipe 2 passes through the U-shaped pressure roller 10, the posture extension and holding structure on the main frame 4 starts to operate accordingly. During this process, the lifting hydraulic cylinder 22 drives the lifting column to extend downward, causing the extension cylinder 23, the vertical end cylinder 24, and the inclined end cylinder 25 to fall synchronously until they fit snugly against the U-shaped concave contour on the insertion pipe 2. In this state, the extension cylinder 23 achieves posture embedding constraint, while the vertical end cylinder 24 forms a guide cut relative to the U-shaped concave contour. The two middle guide columns 32 slide directionally within the corresponding middle guide cylinders 30, ensuring the stability of the lifting posture of the structure composed of the extension cylinder 23, the vertical end cylinder 24, and the inclined end cylinder 25. The posture extension and maintenance structure continuously applies downward pressure and stabilization constraints to the U-shaped pipe section after compression, counteracting the elastic rebound of the inserted pipe 2 itself. This ensures that the inserted pipe 2 maintains a stable shape and is transported forward after leaving the compression zone, reducing cross-sectional restoration caused by elastic reset. This ensures that the inserted pipe 2 smoothly enters the working area of ​​the front winding mechanism. The third servo motor 28 is started, driving the rope release roller 27 in the rope release frame 26 to rotate at a uniform speed. The rotation of the rope release roller 27 releases the pulling rope 29 in an orderly manner. The pulling rope 29 passes through the vertical end cylinder 24, the extension cylinder 23, and the inclined end cylinder 25 in sequence and is laid flat in the U-shaped inner cavity of the inserted pipe 2. If necessary, the front end of the pulling rope 29 can also be positioned relative to the vertical end cylinder 24, the extension cylinder 23, and the inclined end cylinder 25. The front end of the inserted pipe 2 is fixed so that the pulling rope 29 moves in tandem with the insertion pipe 2, forming a follow-up laying pattern. When the U-shaped inserted pipe 2 moves at a constant speed to the working area of ​​the winding mechanism, the winding mechanism enters the linkage operation state, and the binding rope 16 is fixedly connected to the front end of the inserted pipe 2. The fixing of the pulling rope 29 and the binding rope 16 to the inserted pipe 2 can both be done by passing through the auxiliary hole 53 and tying a knot around it, that is, both the pulling rope 29 and the binding rope 16 are fixedly connected to the traction plate frame 3. After the front end of the binding rope 16 is fixed, the first servo motor 13 drives the rotating mounting ring 12 to rotate at a constant speed along the fixed track ring 11. Its rotation speed is the same as that of the inserted pipe 29. The forward speed of the inlet pipe 2 is matched, and the second servo motor 21 synchronously drives the rope take-up frame 15 to rotate, realizing the orderly and controllable release of the binding rope 16. After the binding rope 16 is led out from the rope take-up frame 15, it completes the path auxiliary guidance through the opening slot 18 on the guide plate 17. The limiting bolt 20 installed in the hole 19 limits the travel path of the binding rope 16, preventing the binding rope 16 from escaping from the opening slot 18. The rotating mounting ring 12 drives the rope take-up frame 15 and the guide plate 17 to continuously rotate around the U-shaped insertion pipe 2, spirally wrapping the binding rope 16 around the outside of the U-shaped insertion pipe 2, forming a posture restraint on the U-shaped insertion pipe 2, and maintaining its shape stability after the U-shaped insertion pipe 2 is removed from the main frame 4.

[0031] After the insertion pipe 2 is pressed into a U-shape, the binding rope 16 is also wrapped and reinforced simultaneously. Then, the rear end of the binding rope 16 and the rear end of the pulling rope 29 are connected and tied together, and the connection is fixed relative to the insertion pipe 2. The external traction power equipment then continues to pull the traction frame 3, which, through the traction frame 3, aligns the wrapped and bound U-shaped insertion pipe 2 with the port of the pipe 1 to be repaired. The insertion pipe 2 is then smoothly inserted into the pipe 1. If the insertion pipe 2 is short, it can be directly pushed in. If the insertion pipe 2 is long, the traction rope can be pre-passed through the pipe 1 to be repaired, and then the insertion pipe 2 is pulled through relative to the pipe 1 using the traction rope. During the process, the insertion pipe 2 maintains its U-shape. In a reduced-diameter state, the inserted pipe 2 is inserted smoothly through the entire section of pipe 1 to be repaired until it completely passes through pipe 1, meaning the front end of the inserted pipe 2 extends beyond the other end of pipe 1. The length of the inserted pipe 2 should be greater than the length of pipe 1 to be repaired. After the insertion is completed, both ends of the inserted pipe 2 should be exposed relative to pipe 1. If the length of the inserted pipe 2 is insufficient, multiple inserted pipes 2 can be pre-connected end-to-end. After connection, a U-shaped compression operation is performed on the multiple pre-connected inserted pipes 2. After insertion, the connection binding is released from the positioning of the inserted pipe 2. Using the pull rope 29 pre-laid at the U-shaped position in conjunction with external traction equipment, the binding rope 16 is systematically pulled away from the outer wall of the inserted pipe 2 to release the binding. In addition to restraining the U-shaped posture of the inserted pipe 2, after the entanglement is completely removed, the inserted pipe 2 automatically expands back to its original shape due to its own memory elasticity, adhering to the inner wall of the pipe 1 to be repaired. Then, all the side bolts 50 at the end of the inserted pipe 2 are loosened and removed, and the two traction plate frames 3 and the inner lining plate 54 are removed. At this point, the entire process of the large pipe U-shaped insertion repair device and repair method is completed. Considering the influence of the pulling rope 29 on the binding rope 16, the preset position of the pulling rope 29 relative to the inserted pipe 2 is in the U-shaped area. Since the U-shaped area has a depression, this depression facilitates the placement of the pulling rope 29, thereby reducing the influence of the pulling rope 29 on the binding rope 16. The pulling rope 29 shown in this technical solution is located inside the binding rope 16. This configuration improves the stability of the binding rope 16. During the loosening process, the binding rope 16 allows for the sequential loosening of the U-shaped area on the inserted pipe 2, enabling the binding rope 16 to escape orderly from the loosened area to the unloosened area. Because there is a gap between the unloosened inserted pipe 2 and the pipe 1 to be repaired, the pulling rope 29 and binding rope 16 can be better pulled outwards from the inside of the pipe 1. Similarly, in practical applications, depending on actual needs, if the overall length of the inserted pipe 2 is short, a pulling rope 29 can be installed outside the binding rope 16, or no pulling rope 29 can be installed. Without the pulling rope 29, the U-shaped shape of the inserted pipe 2 can be released by directly pulling the binding rope 16. However, in this state…Controlling the release sequence in the U-shaped posture is quite difficult; during the pulling out of the binding rope 16, it is more necessary to overcome the pressure and friction between the inserted pipe 2 and the pipe to be repaired 1.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A large-scale pipeline U-shaped insertion repair device, comprising the pipeline to be repaired (1), characterized in that, It also includes an insertion pipe (2), a traction assembly, and a pipe forming assembly. The insertion pipe (2) is used to form a through-hole repair into the pipe (1) to be repaired. The traction assembly includes two traction plate frames (3), both of which are fixedly connected to the insertion pipe (2). The pipe forming assembly includes a main frame (4), a downward hydraulic cylinder (5), multiple support rollers (6), multiple first side push rollers (7), and multiple second side push rollers (8). The multiple support rollers (6) are rotatably installed inside the main frame (4). An adjustment mechanism is installed inside the main frame (4). The first side push roller (7) and multiple second side push rollers (8) are installed in the adjustment mechanism. The pressing hydraulic cylinder (5) is installed on the main frame (4), and the lifting column of the pressing hydraulic cylinder (5) is equipped with a lifting wheel frame (9). A deformable pressure roller (10) is rotatably connected inside the lifting wheel frame (9). A posture extension and holding structure is installed on the main frame (4). The posture extension and holding structure is used for the posture extension of the inserted pipe (2) after the deformable pressure roller (10) presses it. A winding mechanism is installed at the front end of the main frame (4). The winding mechanism is used for the shape holding after the inserted pipe (2) is pressed.

2. The large-scale pipeline U-shaped insertion repair device according to claim 1, characterized in that, The winding mechanism includes a fixed track ring (11) and a rotating mounting ring (12). The fixed track ring (11) is fixedly connected to the front end of the main frame (4). The rotating mounting ring (12) is rotatably connected to the fixed track ring (11). A first servo motor (13) is mounted on the rotating mounting ring (12). The first servo motor (13) is used to drive the rotation of the rotating mounting ring (12) relative to the fixed track ring (11). A fixed shaft (14) is fixedly connected to the rotating mounting ring (12). A rotating shaft (14) is rotatably mounted on the fixed shaft (14). A rope take-up frame (15) is provided with a binding rope (16). A guide plate (17) is provided at the front end of the rope take-up frame (15). An opening groove (18) is provided on the guide plate (17). The opening groove (18) is used for guiding the binding rope (16) through. A through hole (19) is provided in the opening groove (18). A limit bolt (20) is provided in the through hole (19). A second servo motor (21) is installed on the rotating mounting ring (12). The second servo motor (21) is used for driving the rotation of the rope take-up frame (15).

3. The large-scale pipeline U-shaped insertion repair device according to claim 2, characterized in that, The posture extension and holding structure includes a lifting hydraulic cylinder (22), which is mounted on the main frame (4). The bottom end of the lifting column of the lifting hydraulic cylinder (22) is fixedly connected to an extension cylinder (23). The end of the extension cylinder (23) near the deforming pressure roller (10) is fixedly connected to a vertical end cylinder (24), and the end of the extension cylinder (23) away from the deforming pressure roller (10) is fixedly connected to an inclined end cylinder (25).

4. The large-scale pipeline U-shaped insertion repair device according to claim 3, characterized in that, The main frame (4) is fixedly connected to a rope feeding frame (26), and a rope feeding roller (27) is rotatably connected inside the rope feeding frame (26). A third servo motor (28) is installed outside the rope feeding frame (26), and the servo shaft of the third servo motor (28) is connected to the rope feeding frame (26) for transmission. A pulling rope (29) is provided on the rope feeding roller (27), and the pulling rope (29) passes through the vertical end cylinder (24), the extension cylinder (23), and the inclined end cylinder (25) in sequence.

5. A large-scale pipeline U-shaped insertion repair device according to claim 4, characterized in that, The main frame (4) is fixedly connected to two central guide cylinders (30) and two side guide cylinders (31). Each of the two central guide cylinders (30) is slidably connected to a central guide column (32). The two central guide columns (32) are fixedly connected to the vertical end cylinder (24) and the inclined end cylinder (25) respectively. Each of the two side guide cylinders (31) is slidably connected to a side guide column (33). The lifting wheel frame (9) is fixedly connected to a tripod (34). Both of the two side guide columns (33) are fixedly connected to the tripod (34).

6. A large-scale pipeline U-shaped insertion repair device according to claim 5, characterized in that, The adjustment mechanism includes a lifting hydraulic cylinder (35), two upper guide columns (36), and two lower guide columns (37). The lifting hydraulic cylinder (35) is mounted on the main frame (4). The two upper guide columns (36) and the two lower guide columns (37) are fixedly connected inside the main frame (4). The two upper guide columns (36) are slidably connected to a first pair of moving frames (38) and a second pair of moving frames (39). The two first pairs of moving frames (38) are slidably connected to the two lower guide columns (37), and the two second pairs of moving frames (39) are slidably connected to the two lower guide columns (37). A first lifting frame (40) is slidably connected between the two first pairs of moving frames (38), and a second lifting frame (40) is slidably connected between the two second pairs of moving frames (39). Two lifting frames (41) are fixedly connected to a synchronous frame (42) on the lifting column of the lifting hydraulic cylinder (35). The first lifting frame (40) and the second lifting frame (41) are both fixedly connected to the synchronous frame (42). The first lifting frame (40) is slidably connected to a first mounting frame (43). Multiple first side push rollers (7) are rotatably connected to the first mounting frame (43). The second lifting frame (41) is slidably connected to a second mounting frame (44). Multiple second side push rollers (8) are rotatably connected to the second mounting frame (44). The first mounting frame (43) and the second mounting frame (44) are both connected to a side push hydraulic cylinder (45). The two side push hydraulic cylinders (45) are respectively connected to the first lifting frame (40) and the second lifting frame (41).

7. A large-scale pipeline U-shaped insertion repair device according to claim 6, characterized in that, The main frame (4) is fixedly connected with a plurality of first side supports (46) and second side supports (47). A plurality of support rollers (6) are rotatably connected to a plurality of first side supports (46) respectively, and a plurality of support rollers (6) are rotatably connected to a plurality of second side supports (47) respectively. A gradient annular groove (48) is provided on each of the plurality of support rollers (6). The gradient annular groove (48) is used for the centering support limit of the inserted pipe (2).

8. A large-scale pipeline U-shaped insertion repair device according to claim 7, characterized in that, Both of the traction plate frames (3) are provided with multiple fixing holes (49), and each of the multiple fixing holes (49) is provided with a side-mounted bolt (50). The end of the insertion pipe (2) is provided with an insertion hole (51), and the multiple insertion holes (51) are respectively matched with the multiple side-mounted bolts (50). Both of the traction plate frames (3) are provided with traction holes (52) and auxiliary mounting holes (53). The traction holes (52) are used for auxiliary pulling of the traction plate frame (3), and the auxiliary mounting holes (53) are used for auxiliary connection and positioning of the binding rope (16). Both of the traction plate frames (3) are provided with inner lining plates (54), and each of the two inner lining plates (54) is provided with a connecting hole (55). The multiple connecting holes (55) are respectively used for the multiple side-mounted bolts (50) to pass through.

9. A large-scale pipeline U-shaped insertion repair device according to claim 8, characterized in that, Lifting rings (56) are provided at the four corners of the top of the main frame (4).

10. A method for repairing large pipelines with U-shaped interlocking joints, characterized in that, The large pipeline U-shaped insertion repair device according to any one of claims 1-9 includes the following steps: S1. First, the main frame (4) is placed and installed stably to provide a foundation for subsequent pressing and insertion operations. Then, the lateral distance between the first side push roller (7) and the second side push roller (8) is adjusted by the adjustment mechanism to make it fit the specifications of the insertion pipe (2). Next, two traction plate frames (3) are installed relative to the insertion pipe (2), and both traction plate frames (3) are connected to the external traction power equipment. S2. Through the smooth traction of the traction component, the insertion pipe (2) passes through the main frame (4) from back to front. As the insertion pipe (2) enters from the rear side of the main frame (4), the insertion pipe (2) is smoothly transported into the main frame (4) and placed on multiple support rollers (6). The lowering hydraulic cylinder (5) is activated. The lowering hydraulic cylinder (5) drives the lifting wheel frame (9) to lower its height, so that the deformation pressure roller (10) moves downward to apply pressure to the insertion pipe (2) and drive the insertion pipe (2) to form a U-shaped deformation process. S3. As the lifting wheel frame (9) applies pressure to the upper side of the insertion pipe (2), the adjustment mechanism operates in combination to adjust the relative position of the first side push roller (7) and the second side push roller (8), applying lateral pressure to the insertion pipe (2), so that the insertion pipe (2) is pressed into a complete U-shaped structure under the coordinated limiting and squeezing action of the deformation pressure roller (10), the support roller (6), the first side push roller (7) and the second side push roller (8); S4. After the deformation pressure roller (10) completes the U-shaped pressing operation on the inserted pipe (2), the posture extension and holding structure is used to constrain the posture of the U-shaped inserted pipe (2) to effectively prevent the inserted pipe (2) from rebounding and resetting due to its own elasticity, so that the inserted pipe (2) can maintain a stable U-shaped shape. At the same time, the winding mechanism at the front end of the main frame (4) is activated to wind and bind the U-shaped inserted pipe (2) to further enhance its shape stability after pressing and reduce structural deformation during the insertion process. S5. By continuing to pull the two traction plates (3), the U-shaped insertion pipe (2) after being wrapped and reinforced is aligned with the pipe to be repaired (1) and passes through the pipe to be repaired (1) at a constant speed, ensuring that the insertion pipe (2) maintains the U-shaped structure throughout the process and passes through the pipe to be repaired (1) smoothly until the insertion pipe (2) is completely inserted through the pipe to be repaired (1). After the insertion is completed, the wrapping constraint on the insertion pipe (2) is released, so that the insertion pipe (2) restores its original circular structure and forms a fit with the inner wall of the pipe to be repaired (1), thus completing the construction of the U-shaped insertion repair of the large pipe.

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