Welding equipment and process for thin-wall thin pipe for pipeline system

Abstract

The invention discloses welding equipment and process for a thin-wall thin pipe for a pipeline system in the technical field of welding devices, the welding equipment comprises a vacuum cavity, the vacuum cavity is formed by two arc-shaped protective shells in a butt joint mode and communicates with an external vacuum generator, and clamping assemblies used for clamping two sections of thin-wall pipes and welding heads are arranged in the protective shells; in the welding process of the thin-walled pipe, internal active regulation and control in the welding process are achieved through the built-in control module, the supporting assembly is arranged to directly provide supporting for the thin-walled pipe from the inside, larger clamping force can be applied to the thin-walled pipe in cooperation with the clamping assembly, the thin-walled pipe is prevented from being clamped and deformed, and the welding quality of the thin-walled pipe is improved. Axial movement of the thin-walled tube under the pushing of gas when high-pressure gas is introduced subsequently is avoided; and the gas pressure intensity of the welding position is controlled through the pressure control unit, the delay problem of remote gas supply is solved, and high-quality welding is achieved.

Description

Technical Field

[0001] This invention relates to the field of welding equipment technology, specifically to a welding device and process for thin-walled tubes used in pipeline systems. Background Technology

[0002] When welding thin-walled tubes, in order to prevent oxidation of the weld joints at high temperatures, existing technologies usually require placing the workpiece in a vacuum chamber and introducing protective gas into the tube. However, due to the low structural rigidity of thin-walled tubes, the imbalance of internal and external pressures during the welding process can easily lead to defects such as pitting and burn-through at the weld joints, which seriously affect the weld formation and joint strength.

[0003] To counteract the pressure difference caused by external low-pressure or vacuum environments, existing methods introduce a protective gas at a certain pressure into the tube to balance the pressure and stabilize the molten pool. However, this method faces a series of derivative problems in practice: First, at least one end of the tube must be sealed before inflation (e.g., Figure 1 After clamping, high-pressure protective gas is input from the other end. The axial thrust F1 generated by the high-pressure gas can easily cause the docking position to move. The clamping mechanism must apply sufficient radial locking force F2 to overcome the movement caused by F1. The increase of F2 can easily cause the thin-walled tube to be clamped and deformed, damaging its roundness and subsequent conveying function.

[0004] Secondly, for slender pipelines with curved sections or used for transportation, it is difficult to set an effective axial limiting structure at the far end, which further increases the difficulty of maintaining docking accuracy under air pressure.

[0005] Furthermore, the gas injected from the end experiences significant flow delay and pressure attenuation as it flows through the slender pipe. The actual pressure at the welding point cannot match the set value in real time and accurately, resulting in unstable protection and support effects and difficulty in ensuring consistent weld quality. Summary of the Invention

[0006] The purpose of this invention is to provide a welding equipment and process for thin-walled tubes for pipeline systems, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a welding device for thin-walled tubes for pipeline systems, comprising a vacuum chamber, wherein the vacuum chamber is composed of two arc-shaped protective shells joined together and connected to an external vacuum generator, and the protective shells are provided with clamping components for clamping two sections of thin-walled tubes and welding heads inside; On both sides of the thin-walled tube welding joint, inside the tube segment corresponding to the clamping assembly, at least one built-in control module that can be inserted into the end of the thin-walled tube is respectively provided. The built-in control module includes: A rigid matrix, the outer diameter of which is smaller than the inner diameter of the thin-walled tube, is used to insert the thin-walled tube; A support assembly, disposed on the rigid substrate, is used for radial expansion to support the thin-walled tube wall from the inside on both sides of the welded joint, and works with the clamping assembly to stably clamp the thin-walled tube and prevent the thin-walled tube from being deformed by clamping. A drive mechanism, mounted on the rigid base and connected to an external controller, is used to control the extension and retraction of the support assembly. A sealing assembly, disposed on the rigid substrate, is used to seal the interior of the thin-walled tube when the support assembly extends radially, forming a local seal at the welding position; A pressure control unit, disposed inside the rigid substrate, is used to maintain the gas pressure in the local isolation space formed by the sealing assembly within a preset range.

[0008] As a further embodiment of the present invention, the support assembly includes a plurality of support rods that slide elastically on the rigid substrate, the support rods penetrating the rigid substrate, and an arc-shaped plate fixedly connected to the end of the support rod.

[0009] As a further embodiment of the present invention, the driving mechanism includes a telescopic member fixedly installed inside a rigid base, and a trapezoidal jacking block is fixedly connected to the surface of the telescopic member corresponding to the position of the support rod. The jacking block is used to push the support rod to extend radially when the telescopic member extends.

[0010] As a further embodiment of the present invention, the sealing assembly includes a telescopic connecting rod hinged between adjacent arc-shaped plates. Both ends of the connecting rod and the arc-shaped plates near the rigid substrate are connected to the rigid substrate by telescopic rods. A soft and annular sealing gasket is provided on the surface of the rigid substrate, and the edge of the sealing gasket is connected to the arc-shaped plates and the connecting rod. The sealing gasket can expand or contract with the radial movement of the arc-shaped plates and the connecting rod.

[0011] As a further embodiment of the present invention, the pressure control unit includes an annular mounting groove fixedly installed inside the rigid substrate. A sealing plug is elastically and slidably connected inside the mounting groove. A pressure relief groove is formed on the surface of the sealing plug near the inside of the rigid substrate. The pressure relief groove extends to the middle of the sealing plug and then penetrates the side wall of the sealing plug. When the gas pressure on the sealing plug is greater than the set pressure, the pressure relief groove is pushed out of the mounting groove and the gas can pass through the sealing plug through the pressure relief groove.

[0012] As a further aspect of the present invention, an auxiliary placement component is also included, which is used to clamp and move the built-in control module to a preset position inside the thin-walled tube; the auxiliary placement component includes multiple push rods mounted by a fixed cylinder, the bottom of the multiple push rods is elastically hinged to a limit plate, the rigid base, the support component in the contracted state, and the sealing gasket can move between the multiple push rods, and a push rod is slidably connected between the push rods.

[0013] As a further embodiment of the present invention, a rotating cylinder is rotatably connected inside the fixed cylinder, and a plurality of L-shaped limiting rods are fixedly connected to the surface of the rotating cylinder, the limiting rods extending to the position of the limiting plate to limit it.

[0014] As a further aspect of the present invention, the rigid substrate is relatively short in length to accommodate the bending portion of the pipeline.

[0015] As a further embodiment of the present invention, the sealing gasket has an annular protrusion at its edge.

[0016] A welding process for thin-walled tubes used in piping systems, the specific steps of which are as follows: Step 1: First, use the auxiliary insertion component to clamp and move the built-in control module to the preset position inside the thin-walled tube; Step 2: Then control the drive mechanism to drive the support component to extend radially. Then, as the support component gradually comes into contact with the inner wall of the thin-walled tube, take out the auxiliary insertion component. The support component can support it from the inner wall of the thin-walled tube. Step 3: During the extension of the support component, the sealing component seals the inside of the thin-walled tube. Then, after the ends of the two thin-walled tubes are joined together, a closed space is formed at the welding position. Step 4: Then move the two thin-walled tubes into the protective shell and align their ends. Then clamp and fix them using the clamping assembly. The clamping assembly, together with the support assembly, can apply sufficient clamping force to the thin-walled tubes. Step 5: Then, high-pressure gas is introduced from one end of the thin-walled tube. When the gas pressure is greater than that of the pressure control unit, it can pass through into the sealed space. When gas is discharged from the other end of the thin-walled tube, the gas pressure in the sealed space reaches the preset range. At this time, the vacuum generator is started to make the vacuum chamber reach the preset low pressure. Step Six: Then start the welding head to perform welding. During the welding process, the pressure control unit can dynamically maintain the pressure stability within the local sealed space. Step 7: After welding is completed, the support and sealing components are contracted and the vacuum is released in sequence. The built-in control module can then be moved out of the thin-walled tube under the push of the gas.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. In the process of welding thin-walled tubes, this invention utilizes a built-in control module to achieve active internal control of the welding process. By setting up a support component to directly support the thin-walled tube from the inside, and cooperating with the clamping component, a greater clamping force can be applied to the thin-walled tube, preventing it from being deformed by clamping and avoiding axial movement of the thin-walled tube under the push of the gas when high-pressure gas is subsequently introduced. Furthermore, by using a pressure control unit to control the gas pressure at the welding position, the problem of delay in remote gas supply is eliminated, achieving high-quality welding.

[0018] 2. In the process of welding thin-walled tubes, multiple support rods can extend from the rigid base to push the arc-shaped plate to support the inside of the thin-walled tube. Multi-directional support from the inside of the thin-walled tube ensures the stability and structural strength of the thin-walled tube when it is subsequently clamped, so that the thin-walled tube can remain stable when high-pressure gas is introduced. The mechanical support rod and arc-shaped plate structure provides the thin-walled tube with strong rigidity and high reliability internal support. The surface contact method disperses the support stress and protects the inner wall of the thin-walled tube from damage.

[0019] 3. When the external controller activates the telescopic component to extend it, the jacking block moves, and its inclined surface pushes multiple support rods outwards to achieve radial extension of the support assembly. When the push rod retracts, the support rods are reset under the action of internal springs. The trapezoidal jacking block drive mechanism efficiently transforms single axial motion into synchronous radial motion of multiple support rods through the inclined surface principle, realizing synchronous, equidistant, and stable extension of the support assembly, ensuring uniform support and avoiding local stress concentration. Attached Figure Description

[0020] Figure 1 A schematic diagram of clamping and welding when sealing one end of a thin-walled tube (in the diagram, V is the flow direction of the protective high-pressure gas, D is the plug, F1 is the axial thrust of the high-pressure gas on D and the thin-walled tube, and F2 is the radial clamping force of the clamping assembly on the thin-walled tube). Figure 2 This is a schematic diagram of the clamping and fastening structure of the thin-walled tube during welding in this invention (F3 in the figure represents the supporting force of the built-in control module on the inner wall of the thin-walled tube, and X represents the preset position. Multiple built-in control modules can be set inside the thin-walled tube to cooperate with the clamping components). Figure 3 This is a process flow diagram of the present invention; Figure 4 This is a schematic diagram of the overall structure of the present invention; Figure 5 This is a schematic diagram of the built-in control module in this invention; Figure 6 This is a schematic diagram of the structure of the built-in control module in this invention after being cut open; Figure 7 for Figure 6Schematic diagram of the structure at point A in the middle; Figure 8 This is a schematic diagram of the structure of the built-in control module after the sealing gasket is hidden. Figure 9 This is a schematic diagram showing the connection relationship between the rigid substrate, the mounting groove, and the sealing plug in this invention. Figure 10 This is a schematic diagram of the auxiliary placement component in this invention; Figure 11 for Figure 10 Schematic diagram of the structure at point B; Figure 12 This is a schematic diagram of the structure of the auxiliary insertion component after it has been cut open in this invention; Figure 13 This is a schematic diagram of the structure in which the built-in control module is placed inside the auxiliary component in this invention; Figure 14 This is a schematic diagram showing the structural relationship between the positioning plate and the built-in control module in the auxiliary placement component of the present invention.

[0021] The attached diagram lists the components represented by each number as follows: 1-Vacuum chamber, 2-Protective shell, 3-Welding head, 4-Rigid base, 5-Support rod, 6-Arc plate, 7-Telescopic component, 8-Pushing block, 9-Connecting rod, 10-Telescopic rod, 11-Sealing gasket, 12-Mounting groove, 13-Sealing plug, 14-Pressure relief groove, 15-Fixing cylinder, 16-Push rod, 17-Limiting plate, 18-Push rod, 19-Rotating cylinder, 20-Limiting rod, 21-Annular protrusion. Detailed Implementation

[0022] Please see Figures 1-14 The present invention provides a technical solution: a welding device for thin-walled tubes for pipeline systems, including a vacuum chamber 1, which is composed of two arc-shaped protective shells 2 joined together and connected to an external vacuum generator. The protective shells 2 are provided with clamping components for clamping two sections of thin-walled tubes and welding heads 3 inside. On both sides of the thin-walled tube welding joint, inside the tube segment corresponding to the clamping assembly, at least one built-in control module that can be inserted into the end of the thin-walled tube is respectively provided. The built-in control module includes: Rigid substrate 4, whose outer diameter is smaller than the inner diameter of the thin-walled tube, is used to insert the thin-walled tube; The support assembly, set on the rigid base 4, is used for radial expansion to support the thin-walled tube wall from the inside on both sides of the welded joint. It works with the clamping assembly to stably clamp the thin-walled tube and prevent the thin-walled tube from being deformed by clamping. The drive mechanism, mounted on the rigid base 4, is connected to an external controller and is used to control the extension and retraction of the drive support assembly. A sealing assembly, mounted on a rigid substrate 4, is used to seal the inside of the thin-walled tube when the support assembly extends radially, forming a local seal at the welding position; The pressure control unit, located inside the rigid substrate 4, is used to maintain the gas pressure in the local isolation space formed by the sealing assembly within a preset range. During the welding process of thin-walled tubes, the built-in control module needs to be moved to a preset position inside the thin-walled tube. Then, the controller commands the drive mechanism to drive the support component to extend radially to support the inner wall of the thin-walled tube. At the same time, the sealing component contacts the tube wall to form a seal. Then, the two sections of thin-walled tubes are moved into the protective shell 2 and their ends are aligned. The clamping component is used to clamp and secure the two sections of thin-walled tubes. The clamping component, together with the support component, can apply a greater clamping force to the thin-walled tubes to prevent them from being deformed by clamping and to prevent the thin-walled tubes from moving axially under the push of the gas when high-pressure gas is introduced later. After clamping, the welding position of the thin-walled tube forms a sealed space. Then, high-pressure protective gas is introduced into it from one end of the thin-walled tube. The pressure control unit can make the gas reach the predetermined pressure and enter the sealed space, thereby ensuring the shape of the weld and the welding quality during the welding of the thin-walled tube.

[0023] As a further embodiment of the present invention, the support assembly includes a plurality of support rods 5 that slide elastically on the rigid base 4, the support rods 5 passing through the rigid base 4, and an arc-shaped plate 6 fixedly connected to the end of the support rods 5; During the welding process of the thin-walled tube, multiple support rods 5 can extend from the rigid base 4 to push the arc plate 6 to support the inside of the thin-walled tube. The multi-directional support from the inside of the thin-walled tube ensures the stability and structural strength of the thin-walled tube when it is clamped later, so that the thin-walled tube can remain stable when high-pressure gas is introduced. The mechanical support rods 5 and arc plate 6 structure provides the thin-walled tube with strong rigidity and high reliability internal support. The surface contact method disperses the support stress and protects the inner wall of the thin-walled tube from damage.

[0024] As a further embodiment of the present invention, the driving mechanism includes a telescopic member 7 fixedly installed inside the rigid base 4, and a trapezoidal jacking block 8 is fixedly connected to the surface of the telescopic member 7 at the position corresponding to the support rod 5. The jacking block 8 is used to push the support rod 5 to extend radially when the telescopic member 7 extends. When the external controller activates the telescopic component 7 to extend it, the jacking block 8 moves, and its inclined surface pushes multiple support rods 5 outwards to achieve radial extension of the support assembly. When the push rod retracts, the support rods 5 are reset under the action of the internal spring. The trapezoidal jacking block 8 drive mechanism efficiently converts the single axial motion into the synchronous radial motion of multiple support rods 5 through the inclined surface principle, realizing the synchronous, equidistant, and stable extension of the support assembly, ensuring uniform support and avoiding local stress concentration.

[0025] As a further embodiment of the present invention, the sealing assembly includes a telescopic connecting rod 9 hinged between adjacent arc-shaped plates 6. The connecting rod 9 and both ends of the arc-shaped plates 6 near the rigid base 4 are connected to the rigid base 4 by telescopic rods 10. A soft and annular sealing gasket 11 is provided on the surface of the rigid base 4, and the edge of the sealing gasket 11 is connected to the arc-shaped plates 6 and the connecting rod 9. The sealing gasket 11 can expand or contract with the radial movement of the arc-shaped plates 6 and the connecting rod 9. During the welding process of the thin-walled tube, when the support rod 5 is pushed out, the arc plate 6 moves outward. Through the linkage of the connecting rod 9 and the telescopic rod 10, the edge of the sealing gasket 11 expands outward synchronously and finally adheres to the inner wall of the thin-walled tube. When high-pressure gas is subsequently introduced, the sealing gasket 11 is pushed by the high-pressure gas to fit tightly with the connecting rod 9, the telescopic rod 10, the support rod 5 and the arc plate 6. The soft sealing gasket 11 is squeezed by the wind force to fit tightly with the inner wall of the thin-walled tube, forming a seal inside the thin-walled tube. This creates a closed space at the welding position, ensuring the welding quality of the weld.

[0026] As a further embodiment of the present invention, the pressure control unit includes an annular mounting groove 12 fixedly installed inside the rigid substrate 4. A sealing plug 13 is elastically and slidably connected inside the mounting groove 12. A pressure relief groove 14 is provided on the surface of the sealing plug 13 near the inside of the rigid substrate 4. The pressure relief groove 14 extends to the middle of the sealing plug 13 and then penetrates the side wall of the sealing plug 13. When the air pressure on the sealing plug 13 is greater than the set pressure, the pressure relief groove 14 is pushed out of the range of the mounting groove 12, and the gas can pass through the pressure relief groove 14 and pass through the sealing plug 13. During the process of introducing high-pressure protective gas into the thin-walled tube, when installing the rigid base 4, the pressure relief grooves 14 need to be aligned in the same direction inside both thin-walled tubes. Gas is then introduced from the end of the thin-walled tube facing the pressure relief groove 14. When no gas is introduced into the pressure relief groove 14, the outlet of the pressure relief groove 14 on the side of the sealing plug 13 is sealed within the side wall of the mounting groove 12 and not connected to the outside. Subsequently, when the pressure exerted by the high-pressure gas on the sealing plug 13 exceeds a preset value, the pressure pushes the sealing plug 13 to compress the spring and move it into the sealing space. After the outlet of the pressure relief groove 14 moves out of the mounting groove 12, the high-pressure gas can enter the sealing space through the pressure relief groove 14 and ventilate the sealing space. As the gas is compressed and the pressure in the sealed space gradually increases, the sealing plug 13 on the other side is pushed by the gas pressure, allowing the gas in the sealed space to be discharged from the other end of the thin-walled tube. At this time, the pressure in the sealed space reaches the preset range, which can ensure the stable welding of the thin-walled tube. During the welding process, the local high temperature at the welding position will cause the gas inside the sealed space to expand, thereby changing the pressure inside the sealed space. At this time, the sealing plug 13 can be pushed to release some gas, so that the pressure inside the sealed space can be kept stable, avoiding the pressure after the gas is filled changing during the welding process, which would affect the welding effect and cause quality problems at the weld point.

[0027] When placing the built-in control module inside the thin-walled tube, the rigid substrate 4 is difficult to maintain stability inside the thin-walled tube. As a further solution of the present invention, an auxiliary placement component is also included, which is used to clamp and move the built-in control module to a preset position inside the thin-walled tube. The auxiliary insertion component includes multiple push rods 16 mounted via a fixed cylinder 15. The bottom of the multiple push rods 16 is elastically hinged to a limit plate 17. The rigid base 4, the support component in the retracted state, and the sealing gasket 11 are movable between the multiple push rods 16. Push rods 18 are slidably connected between the push rods 16. When placing the built-in control module inside the thin-walled tube, the retracted built-in control module needs to be pushed in the same direction as the pressure relief groove 14 between multiple push rods 16. The limiting plate 17 can be pushed to rotate inward. After the rigid base 4 passes through the limiting plate 17, the multiple rigid bases 4 are put into a close fit with the push rod 18. Then, the push rod 18 and the rigid base 4 are moved to a preset position inside the thin-walled tube. Then, the drive mechanism is controlled to move the support rod 5 and the arc plate 6 a certain distance away to ensure that the rigid base 4 will not overturn or tip over. By pressing the push rod 18, the entire rigid base 4 can be pushed into the thin-walled tube to separate it from the push rod 18. The limiting plate 17 can be pushed to flip outward, so that the rigid base 4 can be moved stably into the thin-walled tube to ensure stable support for the thin-walled tube.

[0028] When placing the built-in control module inside the thin-walled tube, the limiting plate 17 is prone to flipping under the weight of the built-in control module or due to misoperation during human movement, which causes the built-in control module to move out of the range of the push rod 18 and damage the built-in control module. As a further solution of the present invention, a rotating cylinder 19 is rotatably connected inside the fixed cylinder 15, and a plurality of L-shaped limiting rods 20 are fixedly connected to the surface of the rotating cylinder 19. The limiting rods 20 extend to the position of the limiting plate 17 to limit it. Before pushing the rigid base 4 into the push rod 16, the limiting rod 20 is rotated outside the range of the limiting plate 17 by the rotating cylinder 19. The limiting plate 17 can be pushed and flipped by the rigid base 4. After the rigid base 4 moves between the push rods 18, the limiting plate 17 returns to its original position. The limiting rod 20 is then rotated to the surface of the limiting plate 17 by the rotating cylinder 19, thereby blocking the limiting plate 17 and preventing it from flipping. This ensures that the rigid base 4 remains fixed during the transfer process. After moving into the thin-walled tube, when it is necessary to release the rigid base 4, the limiting rod 20 is rotated again by the rotating cylinder 19, and the limiting plate 17 can be opened under the push of the rigid base 4 and the push rod 18.

[0029] After the thin-walled tube is welded, the built-in control module inside the thin-walled tube needs to be moved out of the thin-walled tube under the push of gas. However, some thin-walled tubes have a certain bend in the middle, and the rigid base 4 is too long to pass through. As a further solution of the present invention, the rigid base 4 is shorter to accommodate the bend of the pipeline. The rigid base 4 is designed as a short cylindrical shape. This design ensures that the module can pass smoothly through the bends in the pipeline system, guaranteeing the installation space for internal functional components, and greatly facilitating the insertion of the pre-welding built-in control module and its removal after welding.

[0030] As a further embodiment of the present invention, the sealing gasket 11 is provided with an annular protrusion 21 at the edge; When the sealing gasket 11 flattens out under air pressure and fits against the inner wall of the thin-walled tube, the annular protrusion 21 will generate additional elastic deformation, thereby significantly increasing the sealing contact pressure, effectively preventing gas from leaking from the edge of the sealing gasket 11, and improving the sealing reliability of the local sealing space.

[0031] A welding process for thin-walled tubes used in piping systems, the specific steps of which are as follows: Step 1: First, use the auxiliary insertion component to clamp and move the built-in control module to the preset position inside the thin-walled tube; Step 2: Then control the drive mechanism to drive the support component to extend radially. Then, as the support component gradually comes into contact with the inner wall of the thin-walled tube, take out the auxiliary insertion component. The support component can support it from the inner wall of the thin-walled tube. Step 3: During the extension of the support component, the sealing component seals the inside of the thin-walled tube. Then, after the ends of the two thin-walled tubes are joined together, a closed space is formed at the welding position. Step 4: Then move the two thin-walled tubes into the protective shell 2 and align their ends. Then clamp and fix them by the clamping assembly. The clamping assembly, together with the support assembly, can apply sufficient clamping force to the thin-walled tubes. Step 5: Then, high-pressure gas is introduced from one end of the thin-walled tube. When the gas pressure is greater than that of the pressure control unit, it can pass through into the sealed space. When gas is discharged from the other end of the thin-walled tube, the gas pressure in the sealed space reaches the preset range. At this time, the vacuum generator is started to make the vacuum chamber 1 reach the preset low pressure. Step 6: Then start welding head 3 to perform welding. During the welding process, the pressure control unit can dynamically maintain the pressure stability in the local sealed space. Step 7: After welding is completed, the support and sealing components are contracted and the vacuum is released in sequence. The built-in control module can then be moved out of the thin-walled tube under the push of the gas.

Claims

1. A welding device for thin-walled tubes in a piping system, comprising a vacuum chamber (1), wherein the vacuum chamber (1) is composed of two arc-shaped protective shells (2) joined together and connected to an external vacuum generator, wherein the protective shells (2) are provided with clamping components for clamping two sections of thin-walled tubes and a welding head (3); characterized in that: On both sides of the thin-walled tube welding joint, inside the tube segment corresponding to the clamping assembly, at least one built-in control module that can be inserted into the end of the thin-walled tube is respectively provided. The built-in control module includes: A rigid substrate (4) with an outer diameter smaller than the inner diameter of the thin-walled tube is used to insert the thin-walled tube. The support assembly is disposed on the rigid base (4) for radial expansion to support the thin-walled tube wall from the inside on both sides of the welded joint, and works with the clamping assembly to stably clamp the thin-walled tube to prevent the thin-walled tube from being deformed by clamping. A drive mechanism is mounted on the rigid base (4) and connected to an external controller to control the extension and retraction of the support assembly; A sealing assembly is disposed on the rigid substrate (4) and is used to seal the inside of the thin-walled tube when the support assembly extends radially, forming a local seal at the welding position; A pressure control unit is disposed inside the rigid substrate (4) for maintaining the gas pressure in the local isolation space formed by the sealing assembly within a preset range.

2. The welding equipment for thin-walled tubes for pipeline systems according to claim 1, characterized in that: The support assembly includes multiple support rods (5) that slide elastically on the rigid base (4), the support rods (5) penetrate the rigid base (4), and the ends of the support rods (5) are fixedly connected to arc plates (6).

3. The welding equipment for thin-walled tubes for pipeline systems according to claim 2, characterized in that: The driving mechanism includes a telescopic component (7) fixedly installed inside a rigid base (4). A trapezoidal jacking block (8) is fixedly connected to the surface of the telescopic component (7) at the position corresponding to the support rod (5). The jacking block (8) is used to push the support rod (5) to extend radially when the telescopic component (7) extends.

4. The welding equipment for thin-walled tubes for pipeline systems according to claim 2, characterized in that: The sealing assembly includes a telescopic connecting rod (9) hinged between adjacent arc plates (6), and telescopic rods (10) connecting the connecting rod (9) and the arc plates (6) near the rigid base (4) at both ends. A soft and annular sealing gasket (11) is provided on the surface of the rigid base (4), and the edge of the sealing gasket (11) is connected to the arc plates (6) and the connecting rod (9). The sealing gasket (11) can expand or retract with the radial movement of the arc plates (6) and the connecting rod (9).

5. The welding equipment for thin-walled tubes for pipeline systems according to claim 1, characterized in that: The pressure control unit includes an annular mounting groove (12) fixedly installed inside the rigid substrate (4). A sealing plug (13) is elastically and slidably connected inside the mounting groove (12). A pressure relief groove (14) is provided on the surface of the sealing plug (13) near the inside of the rigid substrate (4). The pressure relief groove (14) extends to the middle of the sealing plug (13) and then penetrates the side wall of the sealing plug (13). When the air pressure on the sealing plug (13) is greater than the set pressure, the pressure relief groove (14) is pushed out of the mounting groove (12) and the gas can pass through the pressure relief groove (14) and pass through the sealing plug (13).

6. The welding equipment for thin-walled tubes for pipeline systems according to claim 4, characterized in that: It also includes an auxiliary insertion component for clamping and moving the built-in control module to a preset position inside the thin-walled tube; The auxiliary insertion assembly includes multiple push rods (16) mounted by a fixed cylinder (15), with a limit plate (17) elastically hinged at the bottom of the multiple push rods (16), the rigid base (4), the support assembly in the contracted state, and the sealing gasket (11) being movable between the multiple push rods (16), and a push rod (18) slidably connected between the push rods (16).

7. The welding equipment for thin-walled tubes for pipeline systems according to claim 6, characterized in that: The fixed cylinder (15) is rotatably connected to a rotating cylinder (19), and a plurality of L-shaped limiting rods (20) are fixedly connected to the surface of the rotating cylinder (19). The limiting rods (20) extend to the position of the limiting plate (17) to limit it.

8. The welding equipment for thin-walled tubes for pipeline systems according to claim 1, characterized in that: The rigid substrate (4) is relatively short to accommodate the bends in the pipeline.

9. The welding equipment for thin-walled tubes for pipeline systems according to claim 4, characterized in that: The sealing gasket (11) has an annular protrusion (21) at its edge.

10. A welding process for thin-walled tubes for piping systems, applicable to the welding equipment for thin-walled tubes for piping systems as described in any one of claims 1-9, characterized in that: The specific steps of this process are as follows: Step 1: First, use the auxiliary insertion component to clamp and move the built-in control module to the preset position inside the thin-walled tube; Step 2: Then control the drive mechanism to drive the support component to extend radially. Then, as the support component gradually comes into contact with the inner wall of the thin-walled tube, take out the auxiliary insertion component. The support component can support it from the inner wall of the thin-walled tube. Step 3: During the extension of the support component, the sealing component seals the inside of the thin-walled tube. Then, after the ends of the two thin-walled tubes are joined together, a closed space is formed at the welding position. Step 4: Then move the two thin-walled tubes into the protective shell (2) and align their ends. Then clamp and fix them by the clamping assembly. The clamping assembly, together with the support assembly, can apply sufficient clamping force to the thin-walled tubes. Step 5: Then high pressure gas is introduced from one end of the thin-walled tube. When the gas pressure is greater than that of the pressure control unit, it can enter the sealed space. When gas is discharged from the other end of the thin-walled tube, the gas pressure in the sealed space reaches the preset range. At this time, the vacuum generator is started to make the vacuum chamber (1) reach the preset low pressure. Step 6: Then start the welding head (3) to perform welding. During the welding process, the pressure control unit can dynamically maintain the pressure stability in the local sealed space. Step 7: After welding is completed, the support and sealing components are contracted and the vacuum is released in sequence. The built-in control module can then be moved out of the thin-walled tube under the push of the gas.

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