Segmented Intake Anode Potential Modulation Plasma Uniformity Device for Coating Inside Long Pipelines

Abstract

Segmented air intake anode potential modulation plasma uniformity device for coating inside long pipelines. The present invention aims to solve the problem of uneven film layer deposition on the inner surface of existing long pipelines. In the segmented air intake anode potential modulation plasma uniformity device of the present invention, the segmented gas pipe anodes are multiple hexagonal pipes arranged circumferentially around the central pipe. The multiple segmented gas pipe anodes are connected in sequence to form a gas pipe assembly. Multiple insulating wires and tension wires are threaded through the central pipe of the gas pipe assembly. Each insulating wire is electrically connected to the wire joint in the segmented gas pipe anode. An insulating joint is inserted between adjacent segmented gas pipe anodes in the gas pipe assembly, and end insulating joints are inserted at both ends of the gas pipe assembly. A bellows is connected to the end insulating joint, and the bellows is connected to a tension device. The present invention can arbitrarily combine and increase or decrease the gas pipes according to the length of the pipeline to be coated, adjust the uniformity of air intake, and improve the coating uniformity and film layer quality inside the pipeline.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipeline inner wall processing, and particularly relates to a segmented air inlet anode potential modulation plasma uniformity device for long pipeline internal coating and an application method thereof. Background Art

[0002] At present, pipelines, as an important part of industrial transmission systems, have been widely used. For example, in industrial areas such as petrochemical industry, offshore engineering, automotive industry, food health care, water supply, and sewage treatment. However, since the pipeline wall is always faced with physical substances such as transported materials, acids, and alkalis, it causes corrosion, wear of the pipeline wall and significant economic losses. Existing technologies have adopted a series of coating technologies to solve this problem, such as spraying, electroplating, plasma coating technology, etc. Among many coating technologies, using plasma coating technology to deposit DLC films inside pipelines has achieved good results. The reason is that DLC films have high hardness, high chemical inertness, low friction coefficient and wear rate, as well as excellent corrosion resistance.

[0003] Currently, the main research is still on the inner wall coating of relatively short pipelines (20 cm - 100 cm in length), and the film layer on the inner wall of the pipeline is relatively uniform. However, it is still very difficult to uniformly coat the inner wall of large-length pipe fittings, such as pipelines over 10 m. The main reasons are: (1) The pipeline is relatively long. When using the existing method to introduce gas into the pipeline interior, the gas distribution inside the pipeline is uneven, resulting in uneven plasma distribution during gas discharge inside the pipeline. The film layer thickness and performance prepared inside the pipe are also uneven, with large differences, affecting the use effect of the film layer on the inner wall of the pipe. (2) When the pipeline is too long and large, due to the relatively long distance between the ground electrode anode and the pipeline interior, timely and effective plasma transfer movement cannot be carried out inside the pipeline, resulting in an extremely low plasma density inside the pipeline, or even unable to start glow discharge, seriously affecting the internal coating of the pipeline and restricting the development and application of the long pipeline internal coating technology. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem of uneven deposition of the film layer on the inner surface of existing long pipelines, and to provide a segmented air inlet anode potential modulation plasma uniformity device for long pipeline internal coating and an application method thereof.

[0005] The segmented air inlet anode potential modulation plasma uniformity device for long pipeline internal coating of the present invention includes a plurality of segmented gas guide anodes, insulating joints, rotary valves, insulating wires, wire joints, tensioning devices, and bellows. The segmented gas guide anodes are provided with a plurality of hexagonal tubes in the circumferential direction of the central conduit. A wire joint is arranged inside the central conduit. Densely distributed air holes are opened axially in two opposite hexagonal tubes, and sparsely distributed air holes are opened axially in the remaining hexagonal tubes.

[0006] Multiple segmented gas duct anodes are connected in sequence to form a gas duct assembly. Multiple insulating wires and tensioning steel wires are threaded through the central duct of the gas duct assembly. Each insulating wire is electrically connected to the wire joint in the segmented gas duct anode. An insulating joint is inserted between adjacent segmented gas duct anodes in the gas duct assembly, and end insulating joints are inserted at both ends of the gas duct assembly. A corrugated pipe is connected to the end insulating joint. A rotary valve is coaxially arranged on the end insulating joint and is rotatably connected to the end insulating joint. A plurality of paddles are arranged on the outer circumferential direction of the rotary valve, and two air inlet holes are oppositely opened inside the rotary valve.

[0007] A cross bar is arranged at the end of the corrugated pipe. The tensioning device includes two pull ropes, three pulleys, three counterweights and a fixed rod. The three pulleys are sleeved on the fixed rod. Counterweights are respectively connected to both ends of the cross bar through the pull ropes, and counterweights are also connected to both ends of the tensioning steel wire. The pull ropes bypass the pulleys.

[0008] The application method of the plasma uniform device for modulating the anode potential of segmented air intake in the internal coating of long pipelines according to the present invention is realized according to the following steps:

[0009] I. According to the length of the pipeline to be coated, select segmented gas duct anodes with appropriate lengths, and connect the internal wiring points of each segmented gas duct anode to the insulating wires.

[0010] II. The tensioning steel wire passes through the central duct of each segmented gas duct anode, and then the segmented gas duct anodes are combined and connected. Each two segmented gas duct anodes are connected through a (ceramic) insulating joint and sealed with copper foil to obtain a gas duct assembly.

[0011] III. The gas duct assembly is installed inside the pipeline to be coated. After the two ends of the gas duct assembly are connected to the rotary valve for adjusting air intake and the corrugated pipe and then connected to the air inlet pipe.

[0012] IV. Connect the corrugated pipe to the tensioning device, and hang the counterweights to straighten the gas duct assembly.

[0013] V. Assemble the electrically driven rotating wheel with the paddle of the rotary valve for adjusting air intake to ensure that the rotary valve can rotate stably.

[0014] The segmented air intake anode potential modulation plasma uniformity device for internal coating of long pipelines in the present invention mainly includes: segmented gas guide pipe anodes, insulating joints, high-temperature insulating wires, wire joints, motor rotation devices, tensioning devices, anode power supply systems, gas supply systems, and coordination control systems. In the internal coating process of pipelines, according to the length of the pipeline to be coated, gas guide pipes with uniformly distributed air holes of appropriate length are selected for combination. The internal wiring points of each section of the gas guide pipe are connected to ceramic insulating wires. The tensioning steel wire in the central conduit passes through the gas guide pipe assembly, and each two sections of the gas guide pipe are connected by a ceramic insulating joint and sealed with copper foil. The combined gas guide pipe assembly is installed inside the pipeline to be coated, and its two ends are connected to the rotary valves for adjusting air intake and then connected to bellows and air inlet pipes. The steel wire rope is connected to the tensioning devices at both ends, and appropriate weights are added to straighten the gas guide pipe. The wire terminals of each section of the gas guide pipe are connected to the electrodes at both ends. The rotating wheel driven by electricity is assembled with the paddle of the rotary valve for adjusting air intake to make the rotary valve rotate stably. This device is mainly used in the field of internal coating of pipeline inner walls.

[0015] The segmented air intake anode potential modulation plasma uniformity device for internal coating of long pipelines in the present invention has the following beneficial effects:

[0016] 1. The segmented gas guide pipes are not limited by the length of the pipeline, solving the problem of uneven air intake inside long pipelines. The number of gas guide pipes can be arbitrarily combined and increased or decreased according to the length of the pipeline to be coated, and the air intake uniformity can be adjusted.

[0017] 2. The distribution of air holes on the segmented gas guide pipes can effectively control the air intake direction and air intake uniformity. The function of the bellows is to adapt to the deformation of the device when the steel wire is straightened, reduce the tension on the connection joints of the gas guide pipes, and adapt to the change in the heated length of the gas guide pipes during the coating process.

[0018] 3. Each section of the segmented gas guide pipe is used as an anode and is separately connected to a wire. The power supply is controlled through the anode power supply, and the magnitude of the anode current is adjusted. Furthermore, the electric field near the corresponding anode inside the pipeline can be adjusted to modulate the magnitude of the surrounding plasma density.

[0019] 4. The segmented gas guide pipes can match the air intake volume of each section with the magnitude of the current connected to the gas guide pipe to regulate the magnitude of the plasma density inside the corresponding pipeline, and further control the quality of the film layer deposition inside the gas guide pipe. Description of the Drawings

[0020] Figure 1 It is a schematic diagram of the overall structure of the segmented air intake anode potential modulation plasma uniformity device for internal coating of long pipelines in the present invention;

[0021] Figure 2 It is a schematic diagram of the structure of the insulating joint;

[0022] Figure 3It is a schematic diagram of the internal structure of the insulating joint;

[0023] Figure 4 It is a schematic diagram of the structure of the segmented air guide tube anode;

[0024] Figure 5 It is a structural schematic diagram of a rotary valve;

[0025] Figure 6 It is a schematic diagram of the structure of the tensioned steel wire in the segmented air inlet anode potential modulation plasma uniformity device for coating inside a long pipeline;

[0026] Figure 7 It is a structural schematic diagram of the end insulation joint;

[0027] Figure 8 These are cross-sectional scanning electron microscope images of the DLC film layer at different locations on the inner wall of a 2 m pipe in the application example. DETAILED DESCRIPTION

[0028] Specific implementation method 1: In this implementation method, the segmented air intake anode potential modulation plasma uniformity device for coating inside a long pipeline comprises a plurality of segmented air guide tube anodes 1, an insulating joint 2, a rotary valve 3, an insulating wire 4, a wire joint 5, a tensioning device 6 and a bellows 7. The segmented air guide tube anode 1 is provided with a plurality of hexagonal tubes 1-2 in the circumferential direction of a central conduit 1-1, a wire joint 5 is provided in the central conduit 1-1, two opposite hexagonal tubes 1-2 are provided with densely distributed pores in the axial direction, and the remaining hexagonal tubes 1-2 are provided with sparsely distributed pores in the axial direction;

[0029] A plurality of segmented air guide tube anodes 1 are connected in sequence to form an air guide tube assembly, a plurality of insulated wires 4 and tension wires 10 are inserted in the central conduit 1-1 of the air guide tube assembly, each insulated wire 4 is electrically connected to a wire connector 5 in the segmented air guide tube anode 1, an insulating connector 2 is inserted between adjacent segmented air guide tube anodes in the air guide tube assembly, and end insulating connectors 8 are inserted at both ends of the air guide tube assembly, a bellows 7 is connected to the end insulating connector 8, a rotary valve 3 is coaxially arranged on the end insulating connector 8, the rotary valve 3 is rotatably connected to the end insulating connector 8, a plurality of paddles are arranged in the outer circumferential direction of the rotary valve 3, and two air inlet holes 3-1 are relatively opened in the rotary valve 3;

[0030] A cross bar 7-1 is provided at the end of the corrugated tube 7, and the tensioning device 6 includes two pull ropes 6-1, three pulleys 6-2, three counterweights 6-3 and a fixed rod 6-4. The three pulleys 6-2 are sleeved on the fixed rod 6-4, and the two ends of the cross bar 7-1 are respectively connected to the counterweights 6-3 through the pull ropes 6-1. The two ends of the tensioning wire 10 are also connected to the counterweights 6-3, and the pull ropes 6-1 are passed around the pulleys 6-2.

[0031] In this embodiment, by combining the air ducts in sections, rationally distributing the air holes on the air ducts, connecting the air ducts to electricity as an anode with adjustable current magnitude in sections, and coordinating the air intake with the anode current magnitude to adjust the plasma density distribution in the pipe, the coating uniformity and film quality in the pipe are improved.

[0032] Specific Embodiment 2: The difference between this embodiment and Specific Embodiment 1 is that the material of the sectional air duct anode 1 is stainless steel, and the material of the insulating joint 2 is ceramic.

[0033] Specific Embodiment 3: The difference between this embodiment and Specific Embodiment 1 or 2 is that a plurality of hexagonal tubes 1-2 are welded to the pipe wall of the central duct 1-1.

[0034] Specific Embodiment 4: The difference between this embodiment and any one of Specific Embodiments 1 to 3 is that the insulating wire 4 is connected to the anode power supply.

[0035] The anode power supply system in this embodiment can supply power to multiple anodes simultaneously or adjust the current of each anode separately.

[0036] Specific Embodiment 5: The difference between this embodiment and any one of Specific Embodiments 1 to 4 is that the sectional air duct anode 1 is provided with 6 hexagonal tubes 1-2 in the circumferential direction of the central duct 1-1.

[0037] Specific Embodiment 6: The difference between this embodiment and any one of Specific Embodiments 1 to 5 is that the corrugated pipe 7 is connected to the gas supply pipeline.

[0038] Specific Embodiment 7: The difference between this embodiment and any one of Specific Embodiments 1 to 6 is that the length of the sectional air duct anode 1 is 0.5 - 2 m.

[0039] Specific Embodiment 8: The difference between this embodiment and any one of Specific Embodiments 1 to 7 is that the rotary valve 3 is coordinated with the rotary wheel 9, and the rotary wheel 9 is also provided with a paddle on its circumferential direction.

[0040] Specific Embodiment 9: The difference between this embodiment and any one of Specific Embodiments 1 to 8 is that the segmented air intake anode potential modulation plasma uniformity device for internal coating of the long pipe is placed on the central axis of the pipe to be coated.

[0041] Specific Embodiment 10: The difference between this embodiment and any one of Specific Embodiments 1 to 9 is that when the current on the sectional air duct anode 1 is reduced, the air output of the air holes on the sectional air duct anode 1 is increased.

[0042] Embodiment: The segmented air intake anode potential modulation plasma uniformity device for coating inside a long pipeline in this embodiment includes multiple segmented duct anodes 1, insulating joints 2, rotary valves 3, insulating wires 4, wire connectors 5, tensioning devices 6, and bellows 7. The segmented duct anode 1 has six hexagonal tubes 1-2 circumferentially arranged around a central duct 1-1. A wire connector 5 is arranged inside the central duct 1-1. Densely distributed air holes are opened axially in two opposite hexagonal tubes 1-2, and sparsely distributed air holes are opened axially in the remaining hexagonal tubes 1-2. The opening positions of the densely distributed air holes on different segmented duct anodes 1 are different;

[0043] Multiple segmented duct anodes 1 are connected in sequence to form a duct assembly. Multiple insulating wires 4 and tensioning steel wires 10 are passed through the central duct 1-1 of the duct assembly. Each insulating wire 4 is electrically connected to the wire connector 5 in the segmented duct anode 1. An insulating joint 2 is inserted between adjacent segmented duct anodes in the duct assembly. An insertion through hole 2-1 is opened inside the insulating joint 2. The hexagonal tube 1-2 and the central duct 1-1 in the segmented duct anode are inserted into the insertion through hole 2-1. The six hexagonal tubes 1-2 are isolated from each other. End insulating joints 8 are inserted at both ends of the duct assembly. A bellows 7 is connected to the end insulating joint 8. The rotary valve 3 is coaxially arranged on the end insulating joint 8. The rotary valve 3 is rotatably connected to the end insulating joint 8. Multiple vanes are arranged on the outer circumferential direction of the rotary valve 3. Two air inlets 3-1 are oppositely opened inside the rotary valve 3;

[0044] A cross bar 7-1 is arranged at the end of the bellows 7. The tensioning device 6 includes two pull ropes 6-1, three pulleys 6-2, three counterweights 6-3, and a fixed rod 6-4. The three pulleys 6-2 are sleeved on the fixed rod 6-4. Counterweights 6-3 are respectively connected to both ends of the cross bar 7-1 through the pull ropes 6-1. Counterweights 6-3 are also connected to both ends of the tensioning steel wire 10. The pull rope 6-1 bypasses the pulley 6-2.

[0045] Application Example 1: The process of coating using the segmented air intake anode potential modulation plasma uniformity device for coating inside a long pipeline is as follows:

[0046] 1. Select a pipeline with a length of 2 m and a diameter of 100 mm. Use a pipeline inner wall sandblasting device to remove rust and dirt on the inner wall of the pipeline, and ultrasonically clean it in pure water in a pipeline ultrasonic tank for 30 minutes. Then, dry the inner and outer surfaces of the pipeline with high-pressure air and install it on the pipeline coating equipment;

[0047] 2. According to the length of the pipeline to be coated, select 2 segmented duct anodes with a length of 1 m and a cross-sectional size of 15 mm. Connect the internal wire connectors of the 2 segmented duct anodes to the insulating wires;

[0048] III. Pass the tensioning wire through the central conduit of the segmented gas duct anode, and then conduct combined connection of multiple segmented gas duct anodes. Connect each two combinations of segmented gas duct anodes through a ceramic insulating joint and seal with copper foil.

[0049] IV. Install the combined gas duct assembly inside the pipeline, connect both ends to the rotary valve for regulating air intake and then connect to the intake pipe.

[0050] V. Pass the tensioning wire through the rotary valve and the bellows, connect it to the tensioning devices at both ends, and add counterweights to straighten the gas duct assembly.

[0051] VI. Assemble the electrically driven rotating wheel with the flap of the rotary valve for regulating air intake to ensure the stable rotation of the rotary valve.

[0052] VII. Turn on the mechanical pump, Roots pump, molecular pump in sequence, evacuate the furnace body and the pipeline to a vacuum of 1×10 -3 Pa, then sequentially introduce gases such as Ar gas and acetylene, keep the air pressure at 6 Pa, and turn on the coating power supply for discharge coating.

[0053] VIII. During the film deposition process, the magnitude of the anode current is coordinated with the intake air flow rate of the gas duct. The change of the anode current and the air flow rate are controlled by the electric control system. When changing the anode current, the electric control system adjusts the air flow accordingly. Control the Ar intake flow rate to be 150 sccm, the acetylene flow rate to be 100 sccm, and the anode current changes accordingly. The matching of the anode current and the total gas flow rate parameters is as shown in Table 1 below;

[0054] Table 1 Matching of Anode Current and Total Gas Flow Rate Parameters

[0055]

[0056]

[0057] Application Example 2: The difference between this example and Application Example 1 is that in Step 1, a pipeline with a length of 5 m and a diameter of 100 mm is selected; in Step 2, 2 segmented gas duct anodes with a length of 2 m and a cross-sectional size of 15 mm and 1 segmented gas duct anode with a length of 1 m and a cross-sectional size of 15 mm are selected.

[0058] Application Example 3: The difference between this example and Application Example 1 is that in Step 1, a pipeline with a length of 6 m and a diameter of 100 mm is selected; in Step 2, 3 segmented gas duct anodes with a length of 2 m and a cross-sectional size of 15 mm are selected.

[0059] Application Example 4: The difference between this example and Application Example 1 is that in Step 1, a pipeline with a length of 10 m and a diameter of 100 mm is selected; in Step 2, 5 segmented gas duct anodes with a length of 2 m and a cross-sectional size of 15 mm are selected.

[0060] Comparative Application Example 1: The process of coating using the segmented air intake anode potential modulation plasma uniformity device for coating inside a long pipeline is as follows:

[0061] I. Select a pipeline with a length of 12 m and a diameter of 100 mm. Use the pipeline inner wall sandblasting equipment to remove the rust and dirt on the inner wall of the pipeline, and ultrasonically clean it with pure water in the pipeline ultrasonic tank for 30 min. Then, dry the inner and outer surfaces of the pipeline with high-pressure air and install it on the pipeline coating equipment.

[0062] II. According to the length of the pipeline to be coated, select 4 segmented gas guide tube anodes with a length of 3 m and a cross-sectional size of 15 mm. Connect the internal wire joints of 2 segmented gas guide tube anodes to the insulated wires.

[0063] III. Pass the tensioning wire through the central conduit of the segmented gas guide tube anode, and then connect multiple segmented gas guide tube anodes. Connect each two segmented gas guide tube anode combinations through a ceramic insulation joint and seal it with copper foil.

[0064] IV. Install the combined gas guide tube assembly inside the pipeline. After connecting both ends to the rotary valve for adjusting the air intake and then connecting to the intake pipe.

[0065] V. Pass the tensioning wire through the rotary valve and the bellows, connect it to the tensioning devices at both ends, and add weights to straighten the gas guide tube assembly.

[0066] VI. Assemble the electrically driven rotating wheel with the rotary valve flap for adjusting the air intake to ensure that the rotary valve can rotate stably.

[0067] VII. Sequentially turn on the mechanical pump, Roots pump, molecular pump, and evacuate the furnace body and the pipeline to a vacuum of 1×10 -3 Pa. Then, sequentially introduce gases such as Ar gas and acetylene, keep the air pressure at 6 Pa, and turn on the coating power supply to carry out discharge coating.

[0068] VIII. During the film deposition process, the anode current magnitude and the gas intake flow rate of the gas guide tube are independently adjusted, and there is no matching adjustment by an expert system between them. Adjust the anode current to 100 A, the Ar intake flow rate to 50 sccm, and the acetylene flow rate to 50 sccm.

[0069] Comparative Application Example 2: The process of coating using the segmented air intake anode potential modulation plasma uniformity device for coating inside a long pipeline is as follows:

[0070] I. Select a pipeline with a length of 6 m and a diameter of 100 mm. Use the pipeline inner wall sandblasting equipment to remove the rust and dirt on the inner wall of the pipeline, and ultrasonically clean it with pure water in the pipeline ultrasonic tank for 30 min. Then, dry the inner and outer surfaces of the pipeline with high-pressure air and install it on the pipeline coating equipment. Connect the pipeline to the cathode of the coating power supply.

[0071] II. According to the length of the pipeline to be plated, select 3 segmented gas ducts with a length of 2 m and a cross-sectional size of 15 mm. Each segmented gas duct is not connected to the anode power supply.

[0072] III. Pass the tensioning wire through the central duct of the anode of the segmented gas duct, and then conduct combined connection of multiple segmented gas duct anodes. Each two segmented gas duct anodes are connected through a ceramic insulating joint and sealed with copper foil.

[0073] IV. Install the combined gas duct assembly inside the pipeline. After connecting both ends to the rotary valve for adjusting the intake air, then connect it to the intake pipe.

[0074] V. Pass the tensioning wire through the rotary valve and the intake pipe, connect it to the tensioning devices at both ends, and add counterweights to straighten the gas duct assembly.

[0075] VI. Assemble the electrically driven rotating wheel with the paddle of the rotary valve for adjusting the intake air to ensure that the rotary valve can rotate stably.

[0076] VII. Sequentially turn on the mechanical pump, Roots pump, molecular pump. Evacuate the furnace body and the pipeline to a vacuum of 1×10 -3 Pa, and then sequentially introduce gases such as Ar gas and acetylene. Keep the air pressure at 6 Pa, and turn on the coating power supply to conduct discharge coating.

[0077] Comparative Application Example 3: The difference between this example and Application Example 3 is that a traditional gas duct with a length of 6 m and a diameter of 6 mm (not segmented) is used.

[0078] Through the comparison of the film thickness measurement results of the above Examples 1 - 4, it can be concluded that the film layer thickness on the inner wall of the pipe deposited by the segmented intake anode device is uniform, and the non-uniformity coefficient is less than 5%. Moreover, it is applicable to pipelines of different lengths. From a 2 m pipeline to a 10 m pipeline, the film layer uniformity performs well and the film layer thickness is uniform. Figure 8 It is a cross-sectional scanning electron microscope image of the DLC film layer on the inner wall of a 2 m pipeline. It can be seen that the film layer thickness is relatively uniform. The film layer thickness distribution of the comparative example is significantly affected by the presence or absence of the anode and the uniformity of gas entering the pipeline interior.

[0079] In Comparative Example 1, there is no coordination between the anode current and the intake air flow, resulting in non-uniform film layer thickness at different positions on the inner wall of the pipeline.

[0080] In Comparative Example 2, there is no anode, resulting in the film layer getting thinner and thinner from both ends of the pipeline to the middle position. Due to the absence of the anode electric field, no film layer is deposited at the middle position of the pipeline.

[0081] In Comparative Example 3, the air duct was not segmented and a single air duct was used. Due to the uniform distribution of the air holes, the gas would gradually decrease along the direction of the air flow. When reaching the middle position of the pipeline, there was almost no gas left, resulting in a thinner film layer in the middle of the pipeline and thicker ones at both ends. As shown in Table 2, it was evenly set at 5 positions.

[0082] Table 2 Film layer thickness data of each example

[0083]

Claims

1. Long pipeline internal coating segmented air inlet anode potential modulation plasma uniformity device, Features The long pipe internal coating segmented air intake anode potential modulation plasma uniformity device comprises a plurality of segmented air guide tube anodes (1), an insulating joint (2), a rotary valve (3), an insulating wire (4), a wire joint (5), a tensioning device (6) and a bellows (7). The segmented air guide tube anode (1) is a central conduit (1-1) having a plurality of hexagonal tubes (1-2) arranged in the circumferential direction, a wire joint (5) arranged in the central conduit (1-1), wherein two opposite hexagonal tubes (1-2) are provided with densely distributed air holes in the axial direction, and the remaining hexagonal tubes (1-2) are provided with sparsely distributed air holes in the axial direction; A plurality of segmented air guide tube anodes (1) are connected in sequence to form an air guide tube assembly. A plurality of insulating wires (4) and a tensioning wire (10) are inserted into a central conduit (1-1) of the air guide tube assembly. Each insulating wire (4) is electrically connected to a wire connector (5) in the segmented air guide tube anode (1). An insulating connector (2) is inserted between adjacent segmented air guide tube anodes (1) in the air guide tube assembly. End insulating connectors (8) are inserted at both ends of the air guide tube assembly. A bellows (7) is connected to the end insulating connector (8). A rotary valve (3) is coaxially arranged on the end insulating connector (8). The rotary valve (3) is rotatably connected to the end insulating connector (8). A plurality of paddles are arranged in the outer circumferential direction of the rotary valve (3). Two air inlet holes (3-1) are relatively opened in the rotary valve (3). A cross bar (7-1) is arranged at the end of the corrugated tube (7), and the tensioning device (6) comprises two pull ropes (6-1), three pulleys (6-2), three counterweights (6-3) and a fixed rod (6-4). The three pulleys (6-2) are sleeved on the fixed rod (6-4), and the two ends of the cross bar (7-1) are respectively connected to the counterweights (6-3) through the pull ropes (6-1), and the two ends of the tensioning steel wire (10) are also connected to the counterweights (6-3), and the pull ropes (6-1) are passed around the pulleys (6-2).

2. According to the long pipeline internal coating segmented air inlet anode potential modulation plasma uniformity device according to claim 1, Features The material of the segmented air guide tube anode (1) is stainless steel, and the material of the insulating joint (2) is ceramic.

3. According to the long pipeline internal coating segmented air inlet anode potential modulation plasma uniformity device of claim 1, Features A plurality of hexagonal tubes (1-2) are welded to the tube wall of the central conduit (1-1).

4. According to claim 1, the long pipeline internal coating segmented air inlet anode potential modulation plasma uniformity device, Features The insulated wire (4) is connected to the anode power supply.

5. According to claim 1, the long pipeline internal coating segmented air inlet anode potential modulation plasma uniformity device, Features The segmented air guide tube anode (1) has six hexagonal tubes (1-2) arranged in the circumferential direction of a central conduit (1-1).

6. According to claim 1, the long pipeline internal coating segmented air inlet anode potential modulation plasma uniformity device, Features The corrugated pipe (7) is connected to the gas supply pipeline.

7. The segmented air inlet anode potential modulation plasma uniformity device for internal coating of a long pipeline according to claim 1, characterized in that the length of the segmented gas guide pipe anode (1) is 0.5 - 2 m.

8. The segmented air inlet anode potential modulation plasma uniformity device for internal coating of a long pipeline according to claim 1, characterized in that the rotary valve (3) is matched with the rotary wheel (9), and a paddle is also arranged in the circumferential direction of the rotary wheel (9).

9. The segmented air inlet anode potential modulation plasma uniformity device for internal coating of a long pipeline according to claim 1, characterized in that the segmented air inlet anode potential modulation plasma uniformity device for internal coating of the long pipeline is placed on the central axis of the pipeline to be coated.

10. The segmented air inlet anode potential modulation plasma uniformity device for internal coating of a long pipeline according to claim 1, characterized in that when the current on the segmented gas guide pipe anode (1) decreases, the gas outlet volume of the air holes on the segmented gas guide pipe anode (1) is increased.

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