Dynamic reducing cutting device for pipeline repair and construction method

Abstract

A dynamic variable-diameter cutting device for pipeline repair belongs to the technical field of pipeline repair and comprises a machine head and a variable-diameter structure arranged in the machine head and used for cutting a pipeline, and the variable-diameter structure comprises a rotating component and a variable-diameter component; therefore, the diameter of a circle formed by the four sets of second cutterheads is smoothly increased, it is ensured that the first cutterheads and the second cutterheads make contact with a to-be-cut pipeline-soil body mixture all the time, drill jamming or excessive cutting of undisturbed soil is avoided, meanwhile, through protection of a protective cover, a double-face tooth ring and a second motor are covered inside, and the working efficiency is improved. On this basis, dynamic adjustment of cutting parameters is achieved through the structure, irregular defects such as serious fluctuation and collapse of a pipeline can be precisely treated, precision adjustment is ensured through a driving gear, a first bevel gear and a double-face tooth ring transmission system, the adaptability is improved compared with a pipe cracking method, the system reliability is enhanced, and the service life of the system is prolonged. The maintenance time is shortened.

Description

A dynamic variable diameter cutting device and construction method for pipeline repair Technical Field

[0001] This invention relates to the field of pipeline repair technology, specifically to a dynamic variable diameter cutting device and construction method for pipeline repair. Background Technology

[0002] Currently, in the field of trenchless pipeline repair, for pipelines with severe structural defects such as undulations and collapses, the mainstream and relatively mature overall replacement technologies mainly include the pipe-breaking method and the pipe-eating method.

[0003] CN112647851A (A variable diameter drill bit mechanism for oilfield drilling) and CN111441725A (A variable diameter drill bit for near-horizontal auger drill pipe machines). The first patent focuses on the oilfield drilling field. Its core is to achieve periodic adjustment of the drill bit diameter through a pneumatic control system. It includes components such as a shell, piston chamber, gear mechanism, and cutting head. During operation, gas is injected through the air inlet pipe to push the sliding block, which rotates the disc through gear transmission. The inclined groove design drives the cutting head to expand to compensate for wear and maintain the stability of the well diameter. When the wear is severe, the cutting head is retracted by pumping air for safe removal. The second patent is for coal mining scenarios. It adopts a mechanical-hydraulic combination design, including a sub-drill bit, adjusting plate, adjusting unit, and telescopic unit. The auger shaft drives the connecting column to rotate, causing the sub-drill bit to unfold and dig. During retrieval, the sub-drill bit is tilted and retracted into the drill pipe sleeve by pulling the shaft. The integrated hydraulic oil circuit system ensures smooth movement, while the arc-shaped support rod and ball structure reduce friction.

[0004] Existing variable-diameter drill bit technologies are primarily designed for regular geological formations and cannot effectively address the unique working conditions in pipeline repair. For example, the pneumatic control mechanism in patent CN112647851A exhibits significant limitations in adaptability to irregular defects such as severe undulations and collapses in pipelines. Its rigid structure makes it difficult to achieve true dynamic diameter adjustment, leading to problems such as incomplete cutting or over-cutting during the repair process. Based on the shortcomings of existing technologies, this invention designs a dynamic variable-diameter cutting and replacement construction method for pipeline repair. Summary of the Invention

[0005] This invention provides a dynamic variable diameter cutting device and construction method for pipeline repair. It has an intelligent variable diameter system, which enables dynamic adjustment of cutting parameters and can accurately handle irregular defects such as severe undulations and collapses in pipelines.

[0006] This invention provides the following technical solution: a dynamic variable diameter cutting device for pipe repair, comprising a head and a variable diameter structure disposed inside the head for cutting pipes, the variable diameter structure comprising a rotating component and a variable diameter component; the rotating component comprises: a drive gear rotatably disposed inside the head via a first fixed plate and a second fixed plate, and driven by a meshing gear fixed to the inner wall of the head and driven by a motor; a drill bit passing through the opening of the head and a first cutter disc disposed at the end of the drill bit are disposed on one side of the drive gear; the second fixed plate and the first fixed plate isolate the drive gear inside the head; the variable diameter component comprises: a component disposed on the head via a connecting ring. The machine head includes a fixed plate three inside the head, which is attached to the opening of the machine head; it also includes a double-sided toothed ring that can rotate inside the fixed plate three via a fixed shaft, and the double-sided toothed ring is covered inside the fixed plate three by a protective cover. A motor two is installed inside the protective cover, and the output shaft of the motor two is equipped with a bevel gear one that meshes with the teeth of the double-sided toothed ring. Four equidistant multi-stage telescopic rods are installed on the surface of the fixed plate three, and the ends are connected to bevel gear two that mesh with the double-sided toothed ring and are connected inside the support base. Four sets of equidistant second cutter discs are provided on the outer surface of the fixed plate three. Under normal conditions, the diameter of the circle formed by the four sets of first cutter discs is the same as the diameter of the first cutter disc and the opening of the machine head.

[0007] As a preferred embodiment of the present invention, the four multi-stage telescopic rods are composed of three sets of threaded rods that are sleeved together and mutually limit each other. There is a cavity inside the rods, and a grouting pipe for real-time grouting of the pipe wall is connected to the cavity from the outside.

[0008] As a preferred embodiment of the present invention, four sets of second cutter discs are equidistantly arranged on the outermost lead screw surface of the corresponding multi-stage telescopic rod, and their diameter can change with the extension and retraction of the multi-stage telescopic rod.

[0009] As a preferred embodiment of the present invention, the first cutter head, the fixed plate, and the drive gear are coaxial and have the same holes inside for discharging and transporting slag.

[0010] As a preferred embodiment of the present invention, the tail end of the machine head is provided with a slag discharge pipe communicating with the inside of the machine head, and the slag discharge pipe is provided with a soil discharge auger extending into the inside of the machine head. At the same time, the connection between the machine head and the slag discharge pipe is provided with a slope with a certain taper.

[0011] As a preferred embodiment of the present invention, the outer surface of the slag discharge pipe is provided with a replacement structure, the replacement structure including four motors disposed on the inner wall of the head, a fixed hoop fixed on the outer surface of the slag discharge pipe, and a movable hoop that can slide on the outside of the slag discharge pipe.

[0012] As a preferred embodiment of the present invention, one end of the output shaft of the four motors is fixed with a threaded rod that passes through the machine head and extends to the tail end of the slag discharge pipe, and the outer surface of the four threaded rods is provided with a movable block that is fixed to the movable hoop.

[0013] As a preferred embodiment of the present invention, the outer surface of the fixed hoop is hinged with four sets of first hinge rods, the outer surface of the movable hoop is hinged with four sets of second hinge rods, the four sets of first hinge rods and the four sets of second hinge rods are hinged to each other, and an annular steel plate is hinged above.

[0014] As a preferred embodiment of the present invention, the machine head is provided with three lifting structures on its exterior. The three lifting structures include mounting grooves formed on the surface of the machine head. A third hinge rod is hinged inside the three mounting grooves, and a tire is rotatably mounted at the end of the three third hinge rods. A push cylinder is installed inside the three mounting grooves, and a movable plate is slidably connected to the third hinge rod at one end of the telescopic rod of the three push cylinders.

[0015] A construction method based on the aforementioned dynamic variable diameter cutting device for pipeline repair includes the following steps: S1: Conduct a comprehensive inspection of the pipeline to be repaired, and lower the device into the pipeline for assembly. The device can be independently operated via three push cylinders to adjust the head posture and maintain the stability of the cutting axis; S2: Start the device. In the straight pipe section, the output shaft of one of the two motors drives the meshing gear to rotate. Since the meshing gears on the upper and lower sides mesh with the outer surface of the drive gear, the rotation of the meshing gear can drive the drive gear and the entire variable diameter structure to rotate, thereby enabling uniform rotational cutting to grind the old pipe and the soil intruding into the pipe body into particles smaller than 15mm, approaching the collapsed variable diameter section. At that time, driven by motor two, its output shaft drives bevel gear one to rotate. Since the outer surface of bevel gear one meshes with one side of the teeth of the double-sided toothed ring, the rotation of bevel gear one can drive the double-sided toothed ring to rotate. Since the other side of the double-sided toothed ring meshes with bevel gear two, the rotation of the double-sided toothed ring can cause bevel gear two to drive the corresponding multi-stage telescopic rod to extend and retract outward. This allows the diameter of the four sets of second cutter discs to smoothly increase, ensuring that the first and second cutter discs are always in contact with the "pipe-soil" mixture to be cut, avoiding drill jamming or excessive cutting of the original soil; S3: During the entire cutting process, the external grouting pump station starts synchronously, and the control system calculates the cutting progress (the calculated ring diameter). The system dynamically adjusts the grouting flow rate based on the void volume and real-time grouting pressure. If the pressure sensor shows a sudden pressure increase, it may indicate obstructed grout flow or denser formation, and the system automatically slows down the grouting rate. If the pressure is too low, grout leakage may occur, and the system automatically increases the rate or issues an alarm. The grout immediately fills the annular void behind the cutting area through the grouting pipe within the multi-stage telescopic rod, forming a preliminary protective wall. S4: The soil discharge auger is driven by an external drive source. The slag produced by cutting and grinding is immediately transported backward from the cutting cavity under the rotation of the soil discharge auger. The slag is continuously and closedly transported through a sealed slag discharge pipe to the soil collection hopper in the starting working shaft, and then lifted out by a grab bucket for external transport. S5: When... After a section of old pipe (e.g., a 1-meter-long pipe section) is completely cut and removed, and its position is occupied by the new pipe, the jacking is paused. At this time, four motors are started, and their output shafts drive the threaded rods to rotate. Since the moving blocks are threadedly connected to the threaded rods, when the threaded rods rotate, the four moving blocks can drive the moving hoop rings to move horizontally to the left side of the slag discharge pipe. Also, due to the hinge of the four sets of first and second hinge rods, when the four moving blocks move to the left, they can drive the four annular steel plates to move in the corresponding direction. In this way, the radial force is evenly transmitted to the new pipe, realizing a tight and mechanical lock between the new pipe and the surrounding solidified slurry wall. This process can be carried out in sections and multiple times inside the pipe to ensure overall stability.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention, through a variable diameter structure, allows the device to be used by driving the output shaft of the two motors to rotate the meshing gears. Since the meshing gears on the upper and lower sides mesh with the outer surfaces of the drive gear, the rotation of the meshing gears can drive the drive gear and the entire variable diameter structure to rotate, thereby enabling uniform rotational cutting. When passing through a severely collapsed position, the output shaft of the second motor drives the first bevel gear to rotate. Since the outer surface of the first bevel gear meshes with one side of the double-sided toothed ring, the rotation of the first bevel gear can drive the double-sided toothed ring to rotate. Furthermore, because the other side of the double-sided toothed ring... The toothed ring meshes with the bevel gear II, so when the double-sided toothed ring rotates, the bevel gear II drives the corresponding multi-stage telescopic rod to extend and retract outward. This allows the diameter of the four sets of second cutter discs to smoothly increase, ensuring that the first and second cutter discs are always in contact with the "pipe-soil" mixture to be cut, avoiding jamming or excessive cutting of the original soil. At the same time, the double-sided toothed ring and motor II are protected by a protective cover, preventing soil from entering and getting stuck inside, causing malfunction. Based on this, the cutting parameters can be dynamically adjusted through this structure, which can accurately handle irregular defects such as severe undulations and collapses in the pipeline. It is driven by a transmission system consisting of a drive gear, bevel gear I, and double-sided toothed ring. 1. Ensuring precise adjustment, improved adaptability compared to the pipe-cracking method, enhanced system reliability, and shortened maintenance time; 2. This invention, through a replacement structure, when a section of old pipe (e.g., a pipe section of length in meters) is completely cut and removed, and its position is occupied by a new pipe, the jacking is paused. At this time, four motors are started, causing their output shafts to drive the threaded rods to rotate. Since the moving blocks are threadedly connected to the threaded rods, when the threaded rods rotate, the four moving blocks can drive the moving hoop rings to move horizontally to the left side of the slag discharge pipe. Furthermore, due to the hinge of the four sets of first and second hinge rods, when the four moving blocks move to the left, they can drive the four annular steel plates to move in the corresponding direction, thereby increasing the radial force. The material is evenly transferred to the new pipeline, achieving a tight, mechanical lock between the new pipeline and the surrounding solidified slurry wall. This process can be performed in sections and multiple times within the pipeline to ensure overall stability. 3. Through the lifting structure, the three push cylinders can be operated independently when the machine head is lowered into the pipeline. When the push cylinder is driven, its telescopic rod will drive the moving plate to move back and forth. Since the moving plate is slidably connected to the lower part of the third hinge rod, when the push cylinder telescopic rod retracts, the third hinge rod causes the tire height to increase, and when the push cylinder telescopic rod extends, the third hinge rod causes the tire height to decrease. This is used to adjust the machine head posture when the bottom of the pipeline undulates, and to keep the cutting axis stable. Attached Figure Description

[0017] Figure 1 is a schematic diagram of the external structure of the present invention; Figure 2 is a schematic diagram of the lifting structure of the present invention; Figure 3 is a cross-sectional schematic diagram of the variable diameter structure of the present invention; Figure 4 is a schematic diagram of the first cutter head structure of the present invention; Figure 5 is a schematic diagram of the three planes of the fixing plate of the present invention; Figure 6 is a schematic diagram of the second structure of the motor of the present invention; Figure 7 is a schematic diagram of the drive gear structure of the present invention; Figure 8 is a schematic diagram of the protective cover structure of the present invention; Figure 9 is a schematic diagram of the soil discharge auger structure of the present invention; Figure 10 is a schematic diagram of the replacement structure of the present invention.

[0018] In the diagram: 1. Headstock; 2. Variable diameter structure; 21. Fixed plate one; 22. Fixed plate two; 23. Motor one; 24. Meshing gear; 25. Drive gear; 26. Connecting ring; 27. Drill bit; 28. First cutter head; 29. ​​Fixed plate three; 210. Fixed shaft; 211. Double-sided toothed ring; 212. Motor two; 213. Protective cover; 214. Bevel gear one; 215. Support base; 216. Bevel gear two; 17. Multi-stage telescopic rod; 218. Second cutter head; 3. Slag discharge pipe; 31. Soil discharge auger; 4. Replacement structure; 41. Motor three; 42. Threaded rod; 43. Fixed hoop; 44. Moving hoop; 45. Moving block; 46. First hinge rod; 47. Second hinge rod; 48. Annular steel plate; 5. Lifting structure; 51. Mounting groove; 52. Third hinge rod; 53. Tire; 54. Push cylinder; 55. Moving plate. Detailed Implementation

[0019] 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.

[0020] Example 1 (Referring to Figures 1-10): A dynamic variable diameter cutting device for pipe repair includes a head 1 and a variable diameter structure 2 disposed inside the head 1 for cutting pipes. The variable diameter structure 2 includes a rotating component and a variable diameter component. The rotating component includes a drive gear 25 rotatably disposed inside the head 1 via a first fixed plate 21 and a second fixed plate 22, and meshing with a meshing gear 24 fixed to the inner wall of the head 1 and driven by a first motor 23. A drill bit 27 passing through the opening of the head 1 and a first cutter disc 28 disposed at the end of the drill bit 27 are disposed on one side of the drive gear 25. The second fixed plate 22 and the first fixed plate 21 isolate the drive gear 25 inside the head 1. The variable diameter component includes a third fixed plate 29 disposed inside the head 1 via a connecting ring 26. The fixed plate 29 is attached to the opening of the machine head 1; it also includes a double-sided toothed ring 211 that can rotate inside the fixed plate 29 via a fixed shaft 210, and the double-sided toothed ring 211 is covered inside the fixed plate 29 by a protective cover 213. The protective cover 213 is equipped with a motor 212, and the output shaft of the motor 212 is equipped with a bevel gear 214 that meshes with the teeth of the double-sided toothed ring 211. Four equidistant multi-stage telescopic rods 217 are installed on the surface of the fixed plate 29, and the ends are connected to bevel gears 216 that mesh with the double-sided toothed ring 211 and are connected inside the support base 215; the outer surface of the fixed plate 29 is provided with four sets of equidistant second cutter discs 218. Under normal conditions, the four sets of first cutter discs 28 form a circle with the same diameter as the first cutter disc 28 and the diameter of the opening of the machine head 1. Fixed plates 21 and 22 provide support and sealing during this process, isolating the rotation area of ​​the drive gear 25 from the external environment and preventing soil and debris from entering the transmission system. The rotational motion of the bevel gear 216 is converted into the linear telescopic motion of the multi-stage telescopic rod 217 through an internal screw mechanism. When the multi-stage telescopic rod 217 extends outward, it pushes the second cutter disc 218 installed on its outermost layer to expand radially, so that the diameter of the cutting circle formed by the four second cutter discs 218 increases smoothly; conversely, the diameter decreases when it contracts. The protective cover 213 seals and protects the double-sided toothed ring 211 and the motor 212, preventing the mud and water generated during cutting from entering and causing malfunction. In this way, the cutting diameter can be adjusted in real time and dynamically according to the actual defect shape of the pipeline, ensuring that the cutting head always maintains contact with the "pipeline-soil" mixture to be cut, avoiding drill jamming due to insufficient diameter at the collapse site, or excessive cutting of the original soil due to excessive diameter in the intact section, thus realizing intelligent and adaptive cutting. For Embodiment 2, please refer to Figures 3-8. The four multi-stage telescopic rods 217 are composed of three sets of threaded rods that are sleeved and mutually restrained. There is a cavity inside, and a grouting pipe for real-time grouting of the pipe wall is connected to the cavity from the outside. The four sets of second cutterheads 218 are equidistantly arranged on the outermost threaded rod surface of the corresponding multi-stage telescopic rods 217, and their diameter can change with the extension and retraction of the multi-stage telescopic rods 217.The first cutter head 28, the fixed plate 29, and the drive gear 25 are coaxial and have identical internal holes for discharging and transporting excavated soil. The multi-stage telescopic rod 217 adopts a three-set screw-sleeved structure, ensuring sufficient rigidity and stroke during multi-stage extension and retraction, while also withstanding the radial reaction force from the second cutter head 218 during cutting, preventing skewing or jamming during diameter change. Simultaneously with dynamic diameter-changing cutting, slurry fills the annular gap created by the removal of the old pipe and the expansion of the second cutter head 218 through this built-in channel in real time and in situ.

[0021] For Embodiment 3, please refer to Figures 9-10. The tail end of the machine head 1 is equipped with a slag discharge pipe 3 communicating with the interior of the machine head 1. A soil discharge auger 31 extending into the machine head 1 is installed inside the slag discharge pipe 3. A slope with a certain taper is provided at the connection between the machine head 1 and the slag discharge pipe 3. A replacement structure 4 is provided on the outer surface of the slag discharge pipe 3. The replacement structure 4 includes four motors 41 installed on the inner wall of the machine head 1, a fixed clamping ring 43 fixed to the outer surface of the slag discharge pipe 3, and a movable clamping ring 44 that can slide outside the slag discharge pipe 3. One end of the output shaft of each of the four motors 41 is fixed with a threaded rod 42 that penetrates the machine head 1 and extends to the tail end of the slag discharge pipe 3. Moving blocks 45, which are fixed to the movable clamping rings 44, are provided on the outer surface of the four threaded rods 42. Four sets of first hinge rods 46 are hinged to the outer surface of the fixed hoop 43, and four sets of second hinge rods 47 are hinged to the outer surface of the movable hoop 44. The four sets of first hinge rods 46 and the four sets of second hinge rods 47 are hinged to each other, and an annular steel plate 48 is hinged above them. The inner wall of the connection between the machine head 1 and the slag discharge pipe 3 is designed with a conical slope. This structure plays a role in guiding flow and preventing blockage. It can smoothly guide the slag that may splash or fall back to the starting end of the slag discharge auger 31, avoid the slag from accumulating in corners and forming blockage points, and ensure the continuity of conveying. The slag discharge auger 31 is driven by an external drive source, which is connected to the central shaft of the slag discharge auger 31. When the annular steel plate 48 expands outward, it is pressed evenly against the inner wall of the new pipe, forming a strong radial locking force. This design cleverly transforms the small axial driving force into a larger radial locking force through the first hinge rod 46 and the second hinge rod 47, and ensures the uniformity of circumferential force, realizing a tight, mechanical locking between the new pipe and the surrounding solidified slurry wall, preventing the new pipe from shifting or settling during subsequent use.

[0022] In Example 4, please refer to Figures 1 and 2. The machine head 1 has three lifting structures 5 externally. Each lifting structure 5 includes a mounting groove 51 formed on the surface of the machine head 1. A third hinge rod 52 is hinged inside each of the three mounting grooves 51, and a tire 53 rotates at the end of each of the three third hinge rods 52. A push cylinder 54 is installed inside each of the three mounting grooves 51, and a movable plate 55, slidably connected to the third hinge rod 52, is installed at one end of the telescopic rod of each push cylinder 54. The three lifting structures 5 are distributed at 120-degree angles on the outer circumference of the machine head 1, and each structure is independently controllable. Through independent adjustment of these three points, the undulations of the pipeline foundation can be compensated, and the horizontal and vertical posture of the machine head 1 can be corrected in real time, ensuring that the cutting axis is consistent with the design axis. This is a prerequisite for obtaining high-quality, straight pipeline repair.

[0023] The construction method of the dynamic variable diameter cutting device for pipeline repair described above includes the following steps: S1: Conduct a comprehensive inspection of the pipeline to be repaired, and lower the device into the pipeline for assembly. It can be operated independently via three push cylinders 54. Adjust the position of the cutting head 1 to maintain the stability of the cutting axis; S2: Start the device. In the straight pipe section, the output shaft of the two motors 23 drives the meshing gear 24 to rotate. Since the meshing gears 24 on both sides mesh with the outer surface of the drive gear 25, the rotation of the meshing gear 24 can drive the drive gear 25 and the entire variable diameter structure 2 to rotate, thereby enabling uniform rotational cutting. This grinds the old pipe and the soil intruding into the pipe body into particles smaller than 15mm. When approaching the collapsed variable diameter section, the two motors 23... Driven by 212, its output shaft rotates bevel gear 214. Since the outer surface of bevel gear 214 meshes with one side of the teeth of the double-sided toothed ring 211, its rotation drives the double-sided toothed ring 211 to rotate. Because the other side of the double-sided toothed ring 211 meshes with bevel gear 216, its rotation causes bevel gear 216 to extend and retract the corresponding multi-stage telescopic rod 217 outwards. This allows the four sets of second cutter heads 218 to smoothly increase in diameter, ensuring that the first cutter head 28 and the second cutter head 218 are always in contact with the "pipe-soil" mixture to be cut, preventing drill jamming or excessive cutting of the original soil. S3: During the entire cutting process, the external grouting pump station starts synchronously, controlling... The system dynamically adjusts the grouting flow rate based on the annular void volume calculated from the cutting advance and the real-time grouting pressure. When the pressure sensor shows a sudden increase in pressure, it may indicate that the grout flow is obstructed or the stratum is too dense, and the system automatically slows down the grouting rate. If the pressure is too low, grout leakage may occur, and the system automatically increases the rate or issues an alarm. The grout immediately fills the annular void from behind the cutting area through the grouting pipe in the multi-stage telescopic rod 217, forming a preliminary protective wall. S4: The soil discharge auger 31 is driven by an external drive source. The slag produced by cutting and grinding is immediately transported backward from the cutting cavity under the rotation of the soil discharge auger 31. The slag is continuously and closedly transported to the soil collection hopper in the starting working well through the sealed slag discharge pipe 3, and then lifted out by the grab bucket for external transport. S5: When a After a section of the old pipe, for example, 1 meter in length, is completely cut and removed, and its position is occupied by the new pipe, the jacking is paused. At this time, by starting four motors 41, their output shafts drive the threaded rods 42 to rotate. Since the moving blocks 45 are threadedly connected to the threaded rods 42, when the threaded rods 42 rotate, the four moving blocks 45 can drive the moving hoop 44 to move horizontally to the left side of the slag discharge pipe 3. Furthermore, due to the hinge of the four sets of first hinge rods 46 and second hinge rods 47, when the four moving blocks 45 move to the left, they can drive the four annular steel plates 48 to move in the corresponding direction. Thus, the radial force is evenly transmitted to the new pipe, achieving a tight and mechanical lock between the new pipe and the surrounding solidified slurry wall. This process can be carried out in sections and multiple times within the pipe to ensure overall stability.

[0024] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0025] 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 dynamic variable diameter cutting device for pipe repair, comprising a cutting head (1) and a variable diameter structure (2) disposed inside the cutting head (1) for cutting pipes, characterized in that: The variable diameter structure (2) includes a rotating component and a variable diameter component; the rotating component includes a drive gear (25) that is rotatably disposed inside the head (1) via a fixed plate one (21) and a fixed plate two (22), and is driven by a meshing gear (24) fixed to the inner wall of the head (1) and driven by a motor one (23). A drill bit (27) passing through the opening of the head (1) and a first cutter head (28) disposed at the end of the drill bit (27) are provided on one side of the drive gear (25). The fixed plate two (22) and the fixed plate one (21) isolate the drive gear (25) inside the head (1); the variable diameter component includes a fixed plate three (29) disposed inside the head (1) via a connecting ring (26), and the fixed plate three (29) is in contact with the opening of the head (1); it also includes a fixed shaft (210) A double-sided toothed ring (211) is rotatable inside the fixed plate three (29), and the double-sided toothed ring (211) is covered inside the fixed plate three (29) by a protective cover (213). A motor two (212) is installed inside the protective cover (213), and a bevel gear one (214) that meshes with the teeth of the double-sided toothed ring (211) is installed on the output shaft of the motor two (212). Four equidistant multi-stage telescopic rods (217) are installed on the surface of the fixed plate three (29), and the ends are connected to bevel gear two (216) that meshes with the double-sided toothed ring (211) and is connected inside the support base (215). Four sets of equidistant second cutter discs (218) are provided on the outer surface of the fixed plate three (29). Under normal conditions, the diameter of the four sets of first cutter discs (28) is the same as the diameter of the opening of the first cutter disc (28) and the machine head (1).

2. The dynamic variable diameter cutting device for pipeline repair according to claim 1, characterized in that: The four multi-stage telescopic rods (217) are composed of three sets of threaded rods that are connected and mutually limit each other. There is a cavity inside the rods, and a grouting pipe for real-time grouting of the pipe wall is connected to the cavity from the outside.

3. The dynamic variable diameter cutting device for pipeline repair according to claim 1, characterized in that: The four sets of second cutter discs (218) are equidistantly arranged on the outermost screw surface of the corresponding multi-stage telescopic rod (217), and their diameter can change with the extension and retraction of the multi-stage telescopic rod (217).

4. The dynamic variable diameter cutting device for pipeline repair according to claim 1, characterized in that: The first cutter head (28), the fixed plate three (29) and the drive gear (25) are coaxial and have the same holes inside for discharging and transporting slag.

5. A dynamic variable diameter cutting device for pipeline repair according to claim 1, characterized in that: The tail end of the machine head (1) is provided with a slag discharge pipe (3) that communicates with the inside of the machine head (1), and the slag discharge pipe (3) is provided with a soil discharge auger (31) that extends into the inside of the machine head (1). At the same time, the connection between the machine head (1) and the slag discharge pipe (3) is provided with a slope with a certain taper.

6. A dynamic variable diameter cutting device for pipeline repair according to claim 5, characterized in that: The outer surface of the slag discharge pipe (3) is provided with a replacement structure (4), which includes four motors (41) arranged on the inner wall of the head (1), a fixed hoop (43) fixed on the outer surface of the slag discharge pipe (3), and a movable hoop (44) that can slide outside the slag discharge pipe (3).

7. A dynamic variable diameter cutting device for pipeline repair according to claim 6, characterized in that: One end of the output shaft of the four motors (41) is fixed with a threaded rod (42) that passes through the head (1) and extends to the tail end of the slag discharge pipe (3), and the outer surface of the four threaded rods (42) is provided with a movable block (45) that is fixed to the movable hoop (44).

8. A dynamic variable diameter cutting device for pipeline repair according to claim 6, characterized in that: The outer surface of the fixed hoop (43) is hinged with four sets of first hinge rods (46), and the outer surface of the movable hoop (44) is hinged with four sets of second hinge rods (47). The four sets of first hinge rods (46) and the four sets of second hinge rods (47) are hinged to each other, and an annular steel plate (48) is hinged above.

9. A dynamic variable diameter cutting device for pipeline repair according to claim 1, characterized in that: The machine head (1) is provided with three lifting structures (5) on the outside. The three lifting structures (5) include mounting grooves (51) opened on the surface of the machine head (1). The three mounting grooves (51) are hinged with third hinge rods (52), and the ends of the three third hinge rods (52) are rotated with tires (53). The three mounting grooves (51) are installed with push cylinders (54), and one end of the telescopic rod of the three push cylinders (54) is installed with a moving plate (55) that is slidably connected to the third hinge rods (52).

10. A construction method for a dynamic variable diameter cutting device for pipeline repair based on any one of claims 1-9, characterized in that: Includes the following steps: S1: Conduct a comprehensive inspection of the pipeline to be repaired, and assemble the device inside the pipeline. It can be operated independently by three push cylinders (54). Adjust the posture of the head (1) to keep the cutting axis stable. S2: Start the device. In the straight pipe section, drive the output shaft of the two motors (23) to drive the meshing gear (24) to rotate. Since the meshing gears (24) on the upper and lower sides mesh with the outer surface of the drive gear (25), the drive gear (25) and the entire variable diameter structure (2) can rotate when the meshing gear (24) rotates. This allows for uniform rotational cutting, grinding the old pipe and the soil intruding into the pipe body into particles smaller than 15mm. When approaching the collapsed variable diameter section, drive the two motors (23) to rotate the head (24) to rotate the head (25 ... Driven by 12), its output shaft drives the first bevel gear (214) to rotate. Since the outer surface of the first bevel gear (214) meshes with one side of the teeth of the double-sided toothed ring (211), the double-sided toothed ring (211) can rotate when the first bevel gear (214) rotates. Since the other side of the double-sided toothed ring (211) meshes with the second bevel gear (216), the second bevel gear (216) can drive the corresponding multi-stage telescopic rod (217) to extend and retract to the outside when the double-sided toothed ring (211) rotates. This allows the four sets of second cutter heads (218) to form a circular diameter that smoothly increases, ensuring that the first cutter head (28) and the second cutter head (218) are always in contact with the "pipe-soil" mixture to be cut. S3: During the entire cutting process, the external grouting pump station is started synchronously. The control system dynamically adjusts the grouting flow rate according to the cutting progress and real-time grouting pressure. When the pressure sensor shows a sudden increase in pressure, the system automatically slows down the grouting rate. When the pressure is too low, the system automatically increases the rate or issues an alarm. The grout immediately fills the annular gap from behind the cutting area through the grouting pipe in the multi-stage telescopic rod (217), forming a preliminary protective wall. S4: The soil discharge auger (31) is driven by an external drive source. The slag produced by cutting and grinding is immediately transported from the cutting cavity to the rear under the rotation of the soil discharge auger (31). The slag is continuously and closedly transported to the starting work through the sealed slag discharge pipe (3). The soil in the well is then lifted out by the grab bucket and transported away; S5: When a section of the old pipe is completely cut and removed, and its position is occupied by the new pipe, the jacking is paused. At this time, the output shaft of the four motors (41) is started to drive the threaded rod (42) to rotate. When the threaded rod (42) rotates, the four moving blocks (45) can drive the moving hoop (44) to move horizontally to the left side of the slag discharge pipe (3). When the four moving blocks (45) move to the left, they can drive the four annular steel plates (48) to move in the corresponding direction. Thus, the radial force is evenly transmitted to the new pipe, realizing the tight and mechanical locking between the new pipe and the surrounding solidified slurry wall. This process can be carried out in sections and multiple times in the pipe.

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