Moistureproof MPP cable protection pipe and use method thereof

Abstract

The invention relates to the technical field of cable protection facilities, in particular to a moisture-proof MPP cable protection pipe and a using method thereof.The moisture-proof MPP cable protection pipe comprises a pipe body, the pipe body is composed of an outer pipe and an inner pipe, a connecting rib is connected between the outer pipe and the inner pipe, an interlayer cavity is formed between the outer pipe and the inner pipe, the interlayer cavity is filled with inert gas, and the outer pipe and the inner pipe are connected through the connecting rib. A plurality of breathable micropores are formed in the pipe wall of the inner pipe, a mounting cavity is formed in the inner pipe, and the interlayer cavity is communicated with the mounting cavity through the breathable micropores; through the arrangement of the outer pipe, the inner pipe and the closed interlayer cavity structure, the structural reliability and durability, installation convenience and maintainability of the moisture-proof MPP cable protection pipe are guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cable protection facilities, in particular to a moisture-proof MPP cable protection pipe and a use method thereof. BACKGROUND

[0002] The MPP cable protection pipe, as a protection pipe in the process of cable laying and installation, has the advantages of high strength and high temperature resistance. When laying cables, a plurality of MPP cable protection pipes are connected end to end to form an installation channel for the cables, and the cables are inserted into the installation channel to complete the laying of the cables. In southern and coastal areas, due to high air humidity and possible salt content, the temperature rise in the process of power transmission may cause condensation of moisture in the installation channel of the cables.

[0003] To solve the above problems, the prior art proposes some solutions, for example, patent application No. CN202411960619.7 discloses a moisture-proof MPP cable protection pipe. The pipe has an inner pipe and an outer pipe, and a gauze box containing moisture-proof material is arranged in the cavity between the inner pipe and the outer pipe. A wind-driven impeller drives the gauze box to move back and forth in the pipe body through a complex gear, screw and strong magnetic sliding block linkage mechanism, so that the moisture-proof material in the gauze box alternately absorbs moisture and regenerates. However, the above-mentioned solution still has some problems. The transmission mechanism contains a large number of precise components such as impeller, gear, screw and strong magnetic sliding block, which has the problem of high manufacturing and assembly cost. SUMMARY

[0004] The present application aims to provide a moisture-proof MPP cable protection pipe and a use method thereof to solve the problem of condensation of moisture caused by temperature change in the cable protection pipe, and to solve the problems of complex structure and high assembly cost in the prior art.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions: The utility model provides a kind of moisture-proof MPP cable protection pipe, including pipe body, the pipe body is constituted by outer tube and inner tube, connecting rib is connected between the outer tube and inner tube, interlayer cavity is equipped between the outer tube and inner tube, inert gas is filled in the interlayer cavity, a plurality of gas-permeable micropores are opened on the pipe wall of the inner tube, based on gas molecule diffusion principle, the moisture generated when cable runs can be automatically diffused to dry interlayer cavity, while dry gas can also be trace reverse diffusion, realize the continuous, initiative, unpowered dynamic dehumidification to cable installation cavity, installation cavity is equipped in the inner tube, the interlayer cavity is communicated with installation cavity by a plurality of gas-permeable micropores, cable body is installed in the installation cavity;The utility model discloses outer tube, inner tube and sealed interlayer cavity structure are set, static dry environment is formed by filling inert gas during the operation of cable body, and gas diffusion principle is used to make the moisture in the inner tube be continuously adsorbed by interlayer inert gas by gas-permeable micropore of pipe wall, realize unpowered dynamic dehumidification;By the flexible deformation characteristics of helical connecting rib, stress is dispersed when pipe body is bent, the sealing integrity of interlayer cavity is maintained while guaranteeing structural strength;By socket type connecting pipe and one-way valve, independent sealing unit is formed during installation and maintenance, differential pressure principle is used to realize quick connection and targeted air supply, ensure that local maintenance does not affect the whole system;The design cooperates by above-mentioned structure, avoid the problems, such as complex structure, high assembly cost and easy failure, caused by mechanical transmission mechanism in existing moisture-proof MPP cable protection pipe, ensure the long-term sealing moisture-proof performance, structural reliability and durability, installation convenience and maintainability of moisture-proof MPP cable protection pipe.

[0006] Preferably, the end portion of the pipe body is provided with an end cover, the plurality of end covers are embedded on the front and rear ends of the sandwich cavity, the adjacent pipe bodies are connected through a socket joint pipe, the inner wall of the socket of the socket joint pipe is provided with an annular groove, and the annular groove is provided with an O-shaped ring; the above scheme sets the end cover on the end portion of the pipe body and sets the annular groove and the O-shaped ring in the socket joint pipe, forms a continuous sealing barrier through the multiple static sealing structures in the assembly process, realizes the double sealing effect of the end face and the radial direction by using the elastic compression principle, and effectively prevents the inert gas leakage and the external moisture intrusion; when the socket joint pipe is connected with the end portion of the pipe body, the O-shaped ring is radially compressed in the annular groove to generate a continuous rebound force, and the first sealing barrier is formed; meanwhile, the end cover and the joint surface of the sandwich cavity form the end face sealing under the assembly pressure, and the second protection is formed, the double sealing structure can effectively adapt to the thermal expansion and cold shrinkage of the pipe body caused by the temperature change, and the stability of the sealing interface is maintained; especially, the sealing system and the inert gas in the sandwich cavity form a synergistic protection mechanism; when the gas pressure in the cavity increases due to the temperature rise, the increased internal pressure can further strengthen the sealing effect of the O-shaped ring, and the pressure self-adaptive sealing is formed; the self-enhancing property ensures that the system always maintains excellent air tightness in the long-term operation process; the problems of complex assembly process, leakage at the connection, high maintenance cost and the like caused by the complex mechanical sealing structure of the existing moisture-proof MPP cable protection pipe are avoided, and the overall air tightness, long-term moisture-proof stability, installation convenience and durability of the connection node of the moisture-proof MPP cable protection pipe are ensured.

[0007] Preferably, a pair of insertion pipes are installed on the end cover of the front end, a pair of insertion holes are opened on the end cover of the rear end, the pair of insertion pipes and the pair of insertion holes are communicated with the interlayer cavity, the pair of insertion pipes on the adjacent end covers are embedded in the pair of insertion holes, and a one-way valve is installed in the pair of insertion pipes; the above scheme sets the pair of insertion pipes and the pair of insertion holes with one-way valves on the end covers of the adjacent pipe bodies, realizes quick docking through mechanical interlocking structure in the pipeline connection process, and uses the directional conduction characteristics of the one-way valves to keep the interlayer cavities of the pipe bodies independent in pressure; when the connection is completed by embedding the pair of insertion pipes in the pair of insertion holes, the automatic locking mechanism of the one-way valves ensures that each pipe section keeps an independent sealed state, forming a partitioned and isolated moisture-proof unit system; this design makes the maintenance or replacement of a single pipe section completely not affect the normal operation of other pipe sections, realizes modular maintenance, and in actual application, when a pipe section is damaged due to an accident and the pressure decreases, maintenance personnel only need to connect a special detection device through the pair of insertion pipe interfaces of the pipe section, so as to quickly locate the fault point and implement targeted air supplement; the whole process does not need to disassemble the adjacent pipe sections, the maintenance time is shortened compared with the traditional series structure, and the maintenance cost is reduced; the one-way valve of the design uses a special structure, which can effectively prevent gas from flowing between the cavities during normal operation of the system, and can open the valve core through a special joint to realize one-way air supplement during maintenance; this normally closed design ensures the pressure stability of the system during long-term operation, and avoids the risk of systematic failure caused by local small leakage; the design solves the problems of the traditional series moisture-proof structure, such as the failure of the whole system caused by local leakage, the need to disassemble the whole pipeline during maintenance, ensures the sealing independence of each moisture-proof unit, the accuracy of system maintenance and the long-term reliability of the whole moisture-proof system.

[0008] Preferably, a plurality of annular pieces are installed on the connecting surface of the end cover and the inner wall of the interlayer cavity, and the outer circles of the plurality of annular pieces are inclined to the direction of the end cover; the above scheme sets the annular pieces with the outer circles inclined to the direction of the end cover on the connecting surface of the end cover and the interlayer cavity, when the interlayer cavity is filled with inert gas to form internal pressure, the radial component force generated by the gas pressure acting on the inclined annular pieces makes the pressing degree of the anti-extraction piece and the inner wall of the cavity increase with the increase of the pressure, forming a pressure self-adaptive sealing mechanism; in actual engineering application, when the pipeline is subjected to thermal expansion and contraction due to the diurnal temperature difference or seasonal change, the traditional rigid sealing structure is easy to produce a leakage gap due to material deformation; the self-tightening annular piece of the design can automatically compensate these small deformations, and always maintains effective sealing contact, avoiding the hidden danger of sealing failure or end cover falling off of the traditional sealing structure when the pressure fluctuates, improving the pressure sealing property and connection reliability of the end cover, and ensuring the airtight integrity of the interlayer cavity and the persistent stability of the moisture-proof system of the moisture-proof MPP cable protection pipe during long-term use.

[0009] Preferably, the connecting rib is spirally arranged along the inner wall of the outer tube in the axial direction, the inner wall of the inner tube is integrally formed with a spiral support rib in the axial direction, the inner ring of the support rib is in contact with the cable body, and the inner wall of the inner tube is provided with a spiral heat dissipation channel between the cable body; the above-mentioned scheme is characterized in that: the spiral connecting rib is arranged between the outer tube and the inner tube, and the flexible deformation characteristics of the spiral structure effectively disperse and absorb stress when the pipe body is bent, the spiral line of the support rib in contact with the surface of the cable forms a continuous support point, which not only ensures the stable positioning of the cable, but also greatly reduces the contact area and frictional resistance, making the cable laying operation more smooth, and avoiding the stress concentration and pipe body fracture problems caused by the traditional vertical connecting rib when bending; at the same time, the spiral support rib is arranged on the inner wall of the inner tube, and a continuous heat dissipation channel is formed by the spiral contact between the spiral support rib and the surface of the cable body during the laying and operation of the cable body, the heat dissipation efficiency is significantly improved by enhancing air convection and increasing the heat dissipation area, and the insulation aging problem caused by overheating of the cable body is effectively avoided; especially worth noting is that the double spiral structure shows excellent synergistic effect when the pipe body is subjected to external pressure; the spiral connecting rib of the outer tube uniformly transmits the external load to the inner tube, and the spiral support rib of the inner tube further disperses the load to the entire pipe wall, meeting the mechanical requirements of various complex laying environments; the double spiral structure design jointly ensures the bending resistance, structural durability, efficient heat dissipation capacity and cable body operation safety of the moisture-proof MPP cable protection pipe.

[0010] Preferably, a plurality of flow guide grooves are circumferentially arranged on the inner wall of the inner tube, and a lining layer is embedded on the inner wall of the inner tube, and the lining layer is made of a hydrophobic material; the above-mentioned scheme is characterized in that: a plurality of flow guide grooves are circumferentially arranged on the inner wall of the inner tube, and a hydrophobic material lining layer is embedded, when condensate water appears in the pipe, the low surface energy characteristics of the hydrophobic material make it difficult for water droplets to adhere and quickly slide off, and the water flow collected is guided to the drainage system through the capillary action and gravity of the flow guide grooves, which effectively avoids the local dampness and insulation decline caused by the water film easily adhered to the inner wall of the traditional protection pipe and the condensate water accumulation, and the design is complementary to the spiral support rib; the spiral support rib provides structural support, and its edge is connected with the flow guide groove, forming a three-dimensional drainage channel linked with the support rib and the flow guide groove; the moisture-proof MPP cable protection pipe is ensured to be in a dry state, the cable insulation safety is ensured, and the maintenance-free performance of the system is ensured.

[0011] Preferably, the side wall of the pipe body is provided with a guide groove at both ends, the inner wall of the socket of the socket connection pipe is provided with a guide block, and the guide block is embedded in the guide groove; the above scheme realizes rapid and accurate positioning through the embedding effect of the guide block and the guide groove during pipe connection, overcomes the problems of angle deviation, sealing ring misplacement and large installation resistance of the traditional socket connection, improves the pipe assembly efficiency, ensures the uniform pressure of the O-ring in the annular groove, avoids the risk of sealing and leakage at the connection due to installation deviation, and guarantees the sealing reliability, installation convenience and long-term durability of the moisture-proof MPP cable protection pipe connection system; it is worth noting that the guide system and the O-ring sealing ring form a functional complement; after the pipe body is connected, the guide structure continues to provide radial constraint, and the O-ring sealing ring realizes dynamic sealing under the action of pressure, and the two work together to form a double protection mechanism of mechanical positioning and pressure sealing, which makes the connection system adapt to complex geological subsidence conditions and still maintain effective sealing when the pipe body is displaced at an angle.

[0012] The application also provides a use method of the moisture-proof MPP cable protection pipe. S1: unit pre-inspection and initial filling: in the factory, the interlayer cavity of a single pipe body is initially filled with inert gas and subjected to sealing inspection; S2: on-site system assembly: clean the inside of the pipeline, insert the cable body into the installation cavity, connect adjacent pipe bodies through the socket connection pipe, ensure that the guide block is embedded in the guide groove during connection, and push the pipe body to make the spigot of the previous pipe body completely embedded in the spigot hole of the next pipe body; in this process, the spigot and the spigot hole form mechanical interlocking and physical isolation, and the one-way valve in front of each interlayer cavity remains closed, ensuring that the interlayer cavities of all connected pipe bodies are physically and pressure independent; S3: system-level inert gas filling and pressure establishment: at any spigot of the starting point or the terminal point of the pipeline, connect an external inert gas supply device, and fill the multiple interlayer cavities through this point at one time, until the gas is discharged from the spigot outlet of the other end of the pipeline, confirming that the air in the multiple interlayer cavities has been completely replaced, and a stable working pressure is established; S4: dynamic moisture-proof and heat management during operation: when the cable body is running, the heat generated by the cable body is exchanged with the inert gas in the interlayer cavity through the breathable micropore and the spiral heat dissipation channel, so as to inhibit the generation of condensed water; at the same time, the hydrophobic lining and the flow guide groove are responsible for managing the possible trace of liquid water; S5: Long-term pressure monitoring and convenient maintenance: During the operation of the system, the gas pressure in the interlayer cavity is detected through any reserved socket interface at regular intervals; when the pressure is lower than the preset threshold, the inert gas can be supplemented to the multiple interlayer cavities through the interface, without the need to replace or disassemble any pipe section, so as to restore the moisture-proof performance of the system.

[0013] Compared with the prior art, the beneficial effects of the present application are: 1、The present application is provided with an outer pipe, an inner pipe and a sealed interlayer cavity structure, and a static dry environment is formed by filling inert gas during the operation of the cable body, and the moisture in the inner pipe is continuously adsorbed by the interlayer inert gas through the pipe wall gas-permeable micropores by using the gas diffusion principle, so that unpowered dynamic dehumidification is realized; the long-term sealing and moisture-proof performance, structural reliability and durability, installation convenience and maintainability of the moisture-proof MPP cable protection pipe are ensured.

[0014] 2、The present application is provided with an end cover at the end of the pipe body and an annular groove and an O-ring in the socket type connecting pipe, and a continuous sealed barrier is formed by a multiple static sealing structure during assembly, and the end face and radial double sealing effect is realized by using the elastic compression principle, so that the inert gas leakage and external moisture intrusion are prevented; the overall air-tight integrity, long-term moisture-proof stability, installation convenience and durability of the connecting node of the moisture-proof MPP cable protection pipe are ensured.

[0015] 3、The present application is provided with a socket and a socket pipe with a one-way valve on the end cover of the adjacent pipe body, and quick docking is realized by a mechanical interlocking structure during pipeline connection, and the pressure of the interlayer cavities of each pipe body is kept independent by using the directional conduction characteristics of the one-way valve; the sealing independence of each moisture-proof unit, the precision of system maintenance and the long-term reliability of the overall moisture-proof system are ensured. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a structural schematic view of the moisture-proof MPP cable protection pipe of the present application; Figure 2 It is a structural schematic view of the interlayer cavity in the moisture-proof MPP cable protection pipe of the present application; Figure 3 It is a sectional view of the moisture-proof MPP cable protection pipe of the present application; Figure 4 It is a front view of the moisture-proof MPP cable protection pipe of the present application; Figure 5 It is a state diagram of the adjacent protection pipes in the moisture-proof MPP cable protection pipe of the present application after installation is completed; Figure 6 It is a partial enlarged view of A in the present application; Figure 5 Figure 7 ​Flow chart of the use method of the moisture-proof MPP cable protection pipe.

[0017] In the figure: 1, pipe body; 101, outer pipe; 102, inner pipe; 103, connecting rib; 104, interlayer cavity; 105, air-permeable micropore; 106, mounting cavity; 2, cable body; 3, end cover; 301, counter plug; 302, counter hole; 303, one-way valve; 304, annular sheet; 4, socket type connecting pipe; 401, annular groove; 402, O-ring; 403, guide groove; 404, guide block; 5, supporting rib; 6, heat dissipation channel; 7, flow guide groove; 8, inner lining layer. DETAILED DESCRIPTION

[0018] Please refer to Figures 1 to 7 , the application provides a moisture-proof MPP cable protection pipe and a use method thereof, and the technical scheme is as follows: A moisture-proof MPP cable protection pipe and a use method thereof, please refer to Figures 1 to 7 , the pipe body 1 is composed of an outer pipe 101 and an inner pipe 102, a connecting rib 103 is connected between the outer pipe 101 and the inner pipe 102, the connecting rib 103 is arranged in a spiral shape along the inner wall of the outer pipe 101 in the axial direction, a spiral-shaped supporting rib 5 is integrally formed on the inner wall of the inner pipe 102 in the axial direction, the inner circle of the supporting rib 5 is in contact with the cable body 2, a spiral-shaped heat dissipation channel 6 is arranged between the inner wall of the inner pipe 102 and the cable body 2, an interlayer cavity 104 is arranged between the outer pipe 101 and the inner pipe 102, the interlayer cavity 104 is filled with inert gas, a plurality of air-permeable micropores 105 are formed in the pipe wall of the inner pipe 102, a mounting cavity 106 is arranged in the inner pipe 102, the interlayer cavity 104 is communicated with the mounting cavity 106 through the plurality of air-permeable micropores 105, the cable body 2 is mounted in the mounting cavity 106, end covers 3 are arranged at the ends of the pipe body 1, the plurality of end covers 3 are embedded on the front and rear ends of the interlayer cavity 104, socket type connecting pipes 4 are used to connect adjacent pipe bodies 1, annular grooves 401 are formed in the inner walls of the sockets at both ends of the socket type connecting pipe 4, O-rings 402 are mounted in the plurality of annular grooves 401, a counter plug 301 is mounted on the end cover 3 at the front end, a counter hole 302 is formed in the end cover 3 at the rear end, the counter plug 301 and the counter hole 302 are both communicated with the interlayer cavity 104, the counter plug 301 on the adjacent end cover 3 is embedded in the counter hole 302, a one-way valve 303 is mounted in the counter plug 301, guide grooves 403 are formed in the side walls at the front and rear ends of the pipe body 1, guide blocks 404 are mounted on the inner walls of the sockets at both ends of the socket type connecting pipe 4, the guide blocks 404 are embedded in the guide grooves 403, a plurality of annular sheets 304 are mounted on the connecting surfaces between the end covers 3 and the inner walls of the interlayer cavity 104, the outer circles of the plurality of annular sheets 304 are inclined towards the end covers 3, a plurality of flow guide grooves 7 are circumferentially formed in the inner wall of the inner pipe 102, an inner lining layer 8 is embedded in the inner wall of the inner pipe 102, and the inner lining layer 8 is made of a hydrophobic material.

[0019] In operation, please refer to Figures 1 to 7 , first, in the factory prefabrication stage, each independent pipe body 1 is filled with inert gas and sealed for detection, to ensure that each interlayer cavity 104 forms a sealed moisture-proof unit with rated pressure; during field installation, the cable body 2 is first inserted into the installation cavity 106 of the inner pipe 102, and then the pipe body 1 is connected through the socket connection pipe 4; during the connection process, the precise guidance of the guide block 404 and the guide slot 403 enables the adjacent pipe bodies 1 to be quickly aligned, and at the same time, the plug-in pipe 301 of the front pipe body 1 is inserted into the plug-in hole 302 of the rear pipe body 1 to form mechanical interlocking, at which time the one-way valve 303 of each pipe body 1 remains closed to ensure that the pressure of each interlayer cavity 104 is independent; then, the plug-in pipe 301 at the end of the pipeline is connected to the gas supply equipment for system-level unified filling of inert gas, and through continuous airflow replacement, it is ensured that the multiple interlayer cavities 104 in the entire pipeline reach the standard pressure; During the operation of the cable body 2, the heat generated by the cable body 2 is exchanged with the inert gas in the interlayer cavity 104 through the air-permeable micropore 105 of the inner pipe 102 wall and the heat dissipation channel 6 formed by the spiral support rib 5, thereby inhibiting condensation, and at the same time, the hydrophobic inner lining layer 8 enables the possible trace condensate to quickly slide into the drainage groove 7 and be discharged outside the pipe; when the system needs to be maintained, the pressure of any pipe body 1 plug-in pipe 301 interface is detected, and the individual pipe body 1 with insufficient pressure is targeted for air supplement, and the entire process can restore the moisture-proof performance of the system without disassembling the pipe body 1. Through the synergistic effect of the structures, the complete working process realizes reliable moisture-proof protection throughout the whole cycle from production, installation, operation to maintenance.

[0020] The above describes one specific embodiment of the present application in detail in combination with the drawings, but the present application is not limited to the above described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of these embodiments can be made without departing from the principles and ideas of the present application, and should still fall within the protection scope of the present application.

Claims

1. A moisture-proof MPP cable protection pipe, characterized in that, The device includes a tube body, which is composed of an outer tube and an inner tube. A connecting rib connects the outer tube and the inner tube. An interlayer cavity is provided between the outer tube and the inner tube. The interlayer cavity is filled with an inert gas. Multiple ventilating micropores are opened on the wall of the inner tube. An installation cavity is provided inside the inner tube. The interlayer cavity is connected to the installation cavity through the multiple ventilating micropores. The cable body is installed in the installation cavity.

2. The moisture-proof MPP cable protection pipe according to claim 2, characterized in that: Each end of the tube is provided with an end cap, and multiple end caps are embedded in the front and rear ends of the interlayer cavity. The adjacent tubes are connected by a socket-type connecting pipe. An annular groove is opened on the inner wall of the socket end of the connecting pipe, and an O-ring is installed in multiple annular grooves.

3. The moisture-proof MPP cable protection pipe according to claim 1, characterized in that: The end cap at the front end is equipped with a connecting tube, and the end cap at the rear end is provided with a connecting hole. Both the connecting tube and the connecting hole are connected to the interlayer cavity. The connecting tube on the adjacent end cap is embedded in the connecting hole, and a one-way valve is installed in the connecting tube.

4. The moisture-proof MPP cable protection pipe according to claim 1, characterized in that: Multiple annular plates are installed on the contact surface between the end cap and the inner wall of the interlayer cavity, and the outer rings of the multiple annular plates are inclined towards the end cap.

5. A moisture-proof MPP cable protection pipe according to claim 1, characterized in that: The connecting ribs are arranged in a spiral shape along the inner wall of the outer tube. A spiral support rib is integrally formed along the inner wall of the inner tube. The inner circle of the support rib is in contact with the cable body. A spiral heat dissipation channel is provided between the inner wall of the inner tube and the cable body.

6. A moisture-proof MPP cable protection pipe according to claim 1, characterized in that: The inner tube has multiple flow guide grooves circumferentially formed on its inner wall, and an inner lining layer is embedded in the inner wall of the inner tube. The inner lining layer is made of a hydrophobic material.

7. A moisture-proof MPP cable protection pipe according to claim 1, characterized in that: Guide grooves are provided on the side walls at both ends of the pipe body, and guide blocks are installed on the inner walls of the sockets at both ends of the socket-type connecting pipe, with the guide blocks embedded in the guide grooves.

8. A method of using a moisture-proof MPP cable protection pipe, characterized in that: This method is applied at least to a moisture-proof MPP cable protection pipe as described in any one of the claims, and the specific method includes: S1: Unit pre-inspection and initial filling: In the factory, the interlayer cavity of a single tube is initially filled and inspected with inert gas; S2: On-site systematic assembly: Clean the inside of the pipe, insert the cable body into the installation cavity, connect the adjacent pipes through the socket-type connecting pipe, ensure that the guide block is embedded in the guide groove during connection, and push the pipe body so that the plug of the previous pipe body is fully embedded in the plug hole of the next pipe body; S3: System-level inert gas filling and pressure establishment: At any pair of inlet pipes at the start or end of the pipeline, connect an external inert gas supply device to fill multiple interlayer cavities at once until the gas is discharged from the outlet of the inlet pipe at the other end of the pipeline.

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