A butt welding device and method for a raised face flange with a neck

Abstract

The present application belongs to the technical field of pipeline welding, in particular to a butt welding device and method for butt welding flanges with necks, aiming to solve the problems of large gas consumption, slow air replacement, metal particle splashing and inaccurate butt joint of flange pipelines in traditional methods. The device comprises two semi-ring clamps hinged to each other, which form a sleeve ring after being combined. A clamping mechanism for installing the sleeve ring on the outer wall of the pipeline is arranged in the sleeve ring. An abutting mechanism is arranged in the sleeve ring. The device further comprises an isolation mechanism. The abutting mechanism comprises a fixed ring seat and two latch rods fixed to one side of the fixed ring seat. The isolation mechanism comprises a mandrel, a moving seat I, a moving seat II and a connecting rod. A silica glass fiber ring belt is arranged between the two rubber sealing rings. A dust collecting cover is arranged on the outer wall of the welding gun. A spiral guide groove is arranged on the inner wall of the dust collecting cover. A barb is arranged in the spiral guide groove. The device can reduce argon consumption, improve gas replacement efficiency and effectively capture welding splashes.

Description

Technical Field

[0001] This invention relates to the field of pipeline welding technology, and in particular to a butt welding device and method for a raised-face neck butt welding flange. Background Technology

[0002] Raised-face weld neck flanges are a common pipe connection component, typically connected to pipes using a butt-welding process. During butt welding, it is crucial to ensure precise alignment of the flange's end face with the pipe's end face to guarantee weld quality.

[0003] Existing flange welding devices or methods mostly rely on manual positioning and alignment of flanges, which is cumbersome and difficult to guarantee accuracy. Especially in large-diameter pipelines or in situations where the working environment is restricted, manual operation is difficult and requires high skills from welders. During butt welding, in order to prevent the weld area from being oxidized at high temperatures, it is usually necessary to fill the pipe with a protective gas, such as argon, to replace the air near the weld. However, since the internal space of the pipe is usually large, directly filling the pipe with gas not only consumes a lot of gas, but also has low replacement efficiency, making it difficult to obtain a high-purity protective atmosphere in a short time, which affects the welding quality.

[0004] Therefore, there is a need for a device that can automatically and accurately align flanges and pipes, and efficiently and economically provide gas protection for the weld area. Summary of the Invention

[0005] This invention focuses on achieving high precision, high efficiency, and low loss in flange butt welding. Firstly, addressing the issue of coaxiality deviation in flange butt welding, an automatic flange centering and butt welding structure with a positioning pin as its core was designed to ensure precise coaxial butt welding between the flange and the pipeline. Secondly, addressing the problems of low efficiency and high gas consumption in argon purging protection, a locally isolated argon purging structure with synchronous linkage of dual moving seats was developed, forming a closed isolation chamber in the weld area and significantly reducing protective gas consumption. All structures are adaptable to the conventional working conditions and common flange specifications in pipeline engineering field construction, thus proposing a butt welding device and method for raised-face neck butt welding flanges.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A butt-welding device for a raised-face weld neck flange, comprising: Two semi-circular clamps are hinged together, and the movable ends of the two semi-circular clamps are fixedly connected by bolts. The two semi-circular clamps are combined to form a collar. A clamping mechanism, located inside the collar, is used to install the collar onto the outer wall of the pipe; An abutment mechanism, located inside the collar, is used to align the end face of the flange with the end face of the pipe. The abutment mechanism includes a fixed ring seat and two pins fixed to one side of the fixed ring seat. An isolation mechanism is used to isolate the inner wall of the pipe and flange docking area. The isolation mechanism includes a mandrel and movable seats I and II that are slidably disposed on the outer wall of the mandrel. The clamping mechanism fixes the collar to the outer wall of the pipe, the abutting mechanism aligns the flange with the pipe end face, and the isolation mechanism forms an isolation chamber between the inner walls of the pipe and the flange.

[0007] In one possible design, the clamping mechanism includes a plurality of electric push rods I fixedly passing through the collar, and a clamping plate is fixed to the end of the piston rod of each of the plurality of electric push rods I near the pipe, and a rolling wheel is rotatably provided on the side of each of the plurality of clamping plates near the pipe. The piston rod of the electric push rod I pushes the clamping plate closer to the pipe, fixing the collar to the outer wall of the pipe, and the rolling wheel enables the collar to rotate on the outer wall of the pipe.

[0008] In one possible design, the abutting mechanism further includes two limiting blocks, which are respectively fixed to the inner walls of the two semi-annular clamps. One end of each of the two pin rods slides through the corresponding limiting blocks, and the limiting blocks are bolted with bolts I for abutting against the outer wall of the pin rod. Both of the aforementioned pins are fitted with sliding plates on their outer walls. Each sliding plate has a strip-shaped guide groove, and a sliding seat is slidably connected within the strip-shaped guide groove. The sliding seat is slidably fitted onto the outer wall of the pin via a sliding groove and a slider. An electric push rod II is fixed to the inner wall of the strip-shaped guide groove near the pipe. One end of the piston rod of the electric push rod II is fixedly connected to the sliding seat. A positioning pin for insertion into the flange hole of the flange is fixed to the side of the sliding plate near the semi-annular clamp. The sliding plate is displaced relative to the pin rod by extending and retracting the electric push rod II until the positioning pin is aligned with the flange hole of the flange. The flange is then installed on one side of the sliding plate, the fixing ring seat is pushed to align the end face of the flange with the end face of the pipe, and the bolt I is tightened to position the pin rod.

[0009] In one possible design, a movable platform is slidably sleeved on the outer wall of the pin rod, and a welding gun is fixedly installed on the end of the movable platform near the pipe. A threaded hole is opened on the end of the movable platform away from the welding gun, and a bolt II for abutting against the outer wall of the pin rod is screwed into the threaded hole. By adjusting the position of the moving platform, the welding gun is moved to the weld seam between the pipe and the flange. The bolt II is tightened to fix the position of the moving platform. The fixed ring seat is rotated to drive the collar to rotate, so that the welding gun can weld around the weld seam.

[0010] In one possible design, the isolation mechanism further includes two rubber sealing rings and a silicone fiberglass annular strip fixed between the two rubber sealing rings; Both the outer walls of the movable seat I and the movable seat II are rotatably connected to connecting rod I. The ends of multiple connecting rods I located on the same side away from the spindle are fixedly connected to the corresponding rubber sealing rings. The side of the connecting rod I close to the spindle is rotatably connected to connecting rod II. The end of the connecting rod II away from the connecting rod I is rotatably connected to a hinge seat fixed to the outer wall of the spindle. The outer wall of the mandrel is rotatably connected to a base with multiple transmission gears. Multiple racks II and rack I are fixed on the side of the moving seat I and the moving seat II that are close to each other. The side of the rack I and the rack II that are close to each other are engaged with the corresponding transmission gears. The moving seat II is driven to move towards the moving seat I. Through the transmission of the rack I, the transmission gear and the rack II, the moving seat I and the moving seat II move towards each other. Then, through the rotation of the connecting rod I and the connecting rod II, the two rubber sealing rings abut against the inner wall of the pipe and the inner wall of the flange respectively. The silicone fiberglass annular belt forms an isolation chamber between itself, the two rubber sealing rings and the inner wall of the pipe and the inner wall of the flange.

[0011] In one possible design, the isolation mechanism further includes an exhaust channel and an injection channel disposed within the mandrel; Two flexible hoses are fixed to the outer wall of the mandrel. The ends of the two flexible hoses that are close to each other are connected to the exhaust channel and the gas injection channel, respectively. The ends of the two flexible hoses that are far apart from each other are fixed through the silicone fiberglass annular belt and connected to the isolation chamber. One end of the gas injection channel is used to connect to an external argon gas source. Argon gas is injected into the isolation chamber through the gas injection channel and the corresponding flexible hose, and the original gas in the isolation chamber is discharged through the exhaust channel and the corresponding flexible hose.

[0012] In one possible design, the outer wall of the mandrel is provided with a threaded section, and the mandrel is threadedly fitted with a nut seat through the threaded section. A rotating ring is rotatably connected to one side of the nut seat, and a plurality of support columns are fixed to one side of the rotating ring. One end of each of the plurality of support columns is fixedly connected to one end of the movable seat II. By rotating the nut seat, the nut seat moves axially along the mandrel, and pushes the movable seat II to move via the support column.

[0013] In one possible design, a dust collection hood is also included, which is fixedly fitted onto the outer wall of the welding gun and close to one end of the welding gun head, wherein the top diameter of the dust collection hood is smaller than the bottom diameter. The bottom of the dust collection hood is fixed with an annular pipe, and an air injection pipe connected to the annular pipe is fixedly passed through the dust collection hood. The inner wall of the dust collection hood is provided with a spiral guide groove. The top of the annular pipe is provided with multiple oblique holes, and the orientation of the oblique holes is the same as the spiral direction of the spiral guide groove. Multiple barbs are fixed in the spiral guide groove. The top of the dust collection hood is fixedly connected with an exhaust pipe. Gas is injected into the annular pipe through the gas injection pipe. The gas is ejected obliquely through the inclined hole and forms a rotating airflow under the action of the spiral guide groove. This creates a low pressure at the bottom of the dust collection hood. Under the action of the rotating airflow, the metal droplets hit the inner wall and barbs of the spiral guide groove, rapidly cool and solidify, and adhere to the molten metal, thus being captured.

[0014] In one possible design, an abutment baffle is slidably fitted on the outer wall of the positioning pin, and a helical spring is fitted on the outer wall of the positioning pin. The two ends of the helical spring are respectively fixedly connected to the abutment baffle and the sliding plate on their respective sides by spring seats. When the flange abuts against the end face of the pipe, the compression of the helical spring causes the abutment baffle to slide along the positioning pin to provide clearance.

[0015] The device integrates flange coaxial butt welding, local argon purging protection, circumferential continuous welding, and active spatter capture. The entire flange butt welding process can be completed in one clamping, without the need for multiple clamping and adjustments.

[0016] A method for using a butt-welding device for a raised-face weld neck flange includes the following steps: Two interlocking semi-circular clamps are fitted onto the outer wall of the pipe and the movable end is locked to form a collar. The electric push rod I is activated to push the clamping plate so that the rolling wheel presses against the outer wall of the pipe, allowing the collar to rotate circumferentially. Slide the two pins through the limit block, and drive the sliding seat frame to move in the strip guide groove of the sliding plate through the electric push rod II, so that the positioning pin on the sliding plate is aligned with the flange hole. After the flange is put on, push the fixing ring seat to make the flange end face contact the pipe end face, and press the baffle to compress the spiral spring to absorb the impact. Tighten the bolt I to fix the pins. Insert the mandrel into the pipe and flange, rotate the nut seat to move the moving seat II towards the moving seat I, and drive the two to move in opposite directions through rack I, transmission gear and rack II. Connecting rod I and connecting rod II push the rubber sealing ring to fit the inner wall of the pipe and flange. The silicone fiberglass annular strip covers the gap to form an isolation chamber. Argon gas is injected through the gas injection channel and flexible hose, and impurity gas is discharged through the exhaust channel. Slide the platform along the pin rod to adjust the welding gun to the joint and fix it with bolt II. Rotate the fixing ring seat to drive the sleeve to rotate around the pipe axis and use the welding gun to complete the continuous welding of the annular weld. Compressed air is injected into the annular pipe through the air injection pipe. The gas is ejected through the oblique hole and formed into a rotating airflow under the guidance of the spiral guide groove. The splashing metal droplets are sucked into the dust collection hood, impacted, cooled and solidified, and the gas is discharged through the exhaust pipe.

[0017] Beneficial effects: In this invention, the automatic positioning and axial movement of the flange can be achieved through the cooperation of the pin rod, sliding plate, positioning pin and electric push rod II in the abutment mechanism. The positioning pin is inserted into the flange hole to ensure the consistency between the flange axis and the pipe axis. The electric push rod II provides precise axial displacement control, making the connection process between the flange end face and the pipe end face smooth and accurate. Compared with the traditional manual alignment method, the accuracy and efficiency of the connection are greatly improved. In this invention, the isolation mechanism, through the cooperation of a movable seat, connecting rod, rubber sealing ring, and silicone fiberglass ring belt, forms a small-volume closed isolation chamber in the weld area between the pipe and the flange. Compared to filling the entire pipe with gas for protection, this device only replaces the gas in the extremely small space of the welding area, which greatly reduces the consumption of protective gases such as argon. Due to the small volume of the isolation chamber, the air inside is replaced faster, and a high-purity protective atmosphere can be obtained in a short time, effectively improving welding quality and production efficiency. In this invention, the dust collection hood generates a high-speed rotating airflow through a spiral guide groove and an oblique hole, forming a local negative pressure above the welding area. This actively captures the splashed metal droplets generated during the welding process. Under the action of centrifugal force, the metal droplets impact and cool on the barbs in the spiral guide groove, effectively trapping them and preventing the splashes from falling onto precision parts or equipment. This ensures the cleanliness of the welding operation area, reduces the workload of subsequent cleaning, and protects surrounding equipment.

[0018] In this invention, the combined action of the clamping mechanism, the abutment mechanism, the isolation mechanism, and the dust collection hood solves the problems of low welding accuracy, poor gas replacement efficiency, and difficulty in controlling welding spatter in the prior art during flange welding. It enables precise and automatic welding of flanges and pipelines and facilitates stable circumferential welding. By forming a local isolation chamber, the replacement efficiency of the protective gas is improved and the gas consumption is reduced. At the same time, the rotating airflow captures the splashed metal droplets, effectively ensuring the cleanliness of the welding environment. Attached Figure Description

[0019] Figure 1 A three-dimensional structural schematic diagram of a butt welding device for a raised-face necked butt welding flange provided by the present invention; Figure 2 This is a three-dimensional cross-sectional structural schematic diagram of a butt welding device for a raised-face necked butt welding flange provided by the present invention; Figure 3 A three-dimensional structural schematic diagram of the semi-annular clamp and electric push rod I of a butt welding device for a raised-face necked butt welding flange provided by the present invention; Figure 4 A three-dimensional structural diagram of the electric push rod I and the clamping plate of the butt welding device for a raised-face neck butt welding flange provided by the present invention; Figure 5 A three-dimensional structural diagram of the fixing ring seat, sliding plate and pin rod of the butt welding device for a raised-face neck butt welding flange provided by the present invention; Figure 6 This is a three-dimensional exploded view of the pin rod, sliding seat, and sliding plate of the butt welding device for a raised-face neck butt welding flange provided by the present invention. Figure 7 A cross-sectional view of the silicone fiberglass annular strip and rubber sealing ring of the butt welding device for a raised-face necked butt welding flange provided by the present invention; Figure 8 A three-dimensional structural schematic diagram of the mandrel, silicone fiberglass annular belt and rubber sealing ring of a welding device for a raised-face neck welding flange provided by the present invention; Figure 9 A three-dimensional structural schematic diagram of the connecting rod I, connecting rod II, and rubber sealing ring of a welding device for a raised-face neck welding flange provided by the present invention; Figure 10 This is a three-dimensional exploded view of the rack I, rack II, and transmission gear of the butt welding device for a raised-face necked butt welding flange provided by the present invention; Figure 11 A cross-sectional view of the mandrel of a welding device for a butt-welding flange with a raised face and neck provided by the present invention. Figure 12A three-dimensional structural schematic diagram of the dust collection cover of a welding device for a weld neck flange with a raised face provided by the present invention; Figure 13 This is a three-dimensional cross-sectional view of the dust collection cover of a welding device for a weld neck flange provided by the present invention.

[0020] In the diagram: 1. Semi-circular clamp; 2. Electric push rod I; 3. Clamping plate; 4. Rolling wheel; 5. Limiting block; 6. Pin rod; 7. Bolt I; 8. Fixing ring seat; 9. Bearing seat; 10. Sliding plate; 11. Strip guide groove; 12. Sliding seat frame; 13. Electric push rod II; 14. Positioning pin; 15. Abutment baffle; 16. Helical spring; 17. Moving platform; 18. Welding gun; 19. Mandrel; 20. Moving seat I; 21. Moving seat II; 22. 23. Connecting rod I; 24. Connecting rod II; 25. Rubber sealing ring; 26. Silicone fiberglass ring belt; 27. Nut seat; 28. Support column; 29. ​​Rack I; 20. Rack II; 31. Transmission gear; 32. Flexible hose; 33. Isolation chamber; 34. Exhaust passage; 35. Air injection passage; 36. Bolt II; 37. Dust collection hood; 38. Spiral guide groove; 39. Annular pipe; 40. Angled hole; 41. Air injection pipe; 42. Exhaust pipe; 43. Rotating ring. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] In one embodiment: Refer to Figure 1 and Figure 2 A butt welding device for a raised-face neck butt welding flange, relating to the field of pipeline welding technology, mainly includes two semi-annular clamps 1 that are hinged to each other. The movable ends of the two semi-annular clamps 1 are fixedly connected by bolts. When the movable ends of the two semi-annular clamps 1 are locked by bolts, the two semi-annular clamps 1 merge to form a complete collar. The inner diameter of the collar is larger than the outer diameter of the pipeline to be welded, so that the collar can be fitted onto the outer wall of the pipeline.

[0023] Reference Figures 2-4A clamping mechanism is provided inside the collar to stably install the collar on the outer wall of the pipe. Specifically, the clamping mechanism includes multiple electric push rods I2, which are fixedly inserted through the wall thickness of the collar. The multiple electric push rods I2 are evenly distributed in the circumferential direction of the collar. The piston rod of each electric push rod I2 extends towards the center of the collar. A clamping plate 3 is fixedly connected to the end of the piston rod near the pipe. The clamping plate 3 is arc-shaped, and its curvature matches the curvature of the outer wall of the pipe to increase the contact area. On the side of the clamping plate 3 near the pipe, that is, on the inner arc surface of the clamping plate 3, a rolling wheel 4 is rotatably arranged. The axis of the rolling wheel 4 is parallel to the axis of the pipe.

[0024] By extending the piston rod of the electric push rod I2, the clamping plate 3 is pushed closer to the outer wall of the pipe until the rolling wheel 4 on the clamping plate 3 is in close contact with the outer wall of the pipe, thereby clamping and fixing the collar to the outer wall of the pipe. Since the clamping plate 3 and the outer wall of the pipe are in point contact with the rolling wheel 4, the entire collar can still rotate circumferentially relative to the outer wall of the pipe by the rolling wheel 4, provided that the clamping plate 3 provides sufficient clamping force.

[0025] Reference Figure 2 and Figure 5 The collar is also equipped with an abutment mechanism, which is used to align the end face of the flange with the end face of the pipe. The abutment mechanism includes a fixed ring seat 8 and two pins 6 fixed on one side of the fixed ring seat 8. The fixed ring seat 8 is a ring structure with an inner diameter larger than the outer diameter of the collar. The two pins 6 are parallel to each other, and one end of each pin is fixed on the same side of the fixed ring seat 8. The axial direction of the pins 6 is parallel to the axial direction of the pipe.

[0026] Reference Figure 3 and Figure 5 The abutment mechanism also includes two limiting blocks 5, which are fixed on the inner walls of the two semi-annular clamps 1 respectively. Each limiting block 5 has a through guide hole. The ends of the two pins 6 away from the fixed ring seat 8 slide through the guide holes on the corresponding limiting blocks 5. Each limiting block 5 is also threaded with a bolt I7. The end of the bolt I7 extends into the guide hole. After the pins 6 are adjusted to the position, the bolt I7 is tightened so that its end abuts against the outer wall of the pins 6, thereby fixing the position of the pins 6.

[0027] Reference Figure 5 and Figure 6A sliding plate 10 is slidably fitted on the outer wall of each of the two pin rods 6. Each sliding plate 10 has a strip-shaped guide groove 11, the length of which is parallel to the axial direction of the pin rod 6. A sliding seat 12 is slidably connected in each strip-shaped guide groove 11. The sliding seat 12 is slidably fitted on the outer wall of the pin rod 6 through a sliding groove and slider cooperation structure. An electric push rod II 13 is fixed on the inner wall of the strip-shaped guide groove 11 near the pipe. One end of the piston rod of the electric push rod II 13 is connected to the sliding groove. The movable seat 12 is fixedly connected. Therefore, when the piston rod of the electric push rod II 13 extends or retracts, it can drive the sliding seat 12 to slide in the strip guide groove 11. Since the sliding seat 12 is slidably engaged with the pin rod 6, and the sliding plate 10 is connected to the sliding seat 12 through the strip guide groove 11, the axial movement of the sliding plate 10 relative to the pin rod 6 is realized. A positioning pin 14 is fixed on the side of each sliding plate 10 near the semi-annular clamp 1. The positioning pin 14 is used to insert into the flange hole of the flange to realize the positioning and fixing of the flange.

[0028] Reference Figure 1 and Figure 5 In order to balance the weight of the two ends of the pin rod 6 and prevent the pin rod 6 from tilting after the sliding plate 10 is connected to the flange, a bearing seat 9 is slidably sleeved on the outer wall of the two pin rods 6. The bearing seat 9 is located at the end of the pin rod 6 away from the fixed ring seat 8. The bearing seat 9 can be designed as a counterweight with a certain weight, or as a support structure that can slide along the pin rod 6 to balance the weight of the fixed ring seat 8 and the sliding plate 10.

[0029] When the welding device is in operation, firstly, two semi-circular clamps 1 are placed on the outer wall of the pipe to be welded. The movable ends of the two semi-circular clamps 1 are fixed with bolts to form a collar. Then, multiple electric push rods I2 are activated. The piston rods of the electric push rods I2 push the clamping plate 3 to move towards the pipe until the rolling wheel 4 on the clamping plate 3 is in close contact with the outer wall of the pipe, fixing the collar to the outer wall of the pipe. At this time, the collar can rotate on the outer wall of the pipe through the rolling wheel 4. Next, the two pins 6 of the abutment mechanism are passed through the guide holes of the two limit blocks 5 from the outside of the pipe. Then, by controlling the extension and retraction of the piston rod of the electric push rod II 13, the sliding plate 10 is moved along the axial direction of the pins 6 until the positioning pin 14 on the sliding plate 10 is aligned with the flange hole on the flange to be welded. The flange is then fitted onto the positioning pin 14 through its flange hole, thereby installing the flange on one side of the sliding plate 10. At this time, the axis of the flange is aligned with the axis of the pipe. Then, the operator pushes the fixed ring seat 8, which drives the two pin rods 6, the sliding plate 10, and the flange fixed on the sliding plate 10 to move together toward the pipeline until the end face of the flange and the end face of the pipeline come into contact and align. After the flange and the end face of the pipeline come into contact, the bolt I7 is tightened so that its end abuts against the pin rod 6, fixing the position of the pin rod 6 and the entire abutment mechanism, thereby completing the precise alignment and positioning of the flange and the pipeline.

[0030] Reference Figure 5 The outer wall of the pin rod 6 is also slidably fitted with a moving platform 17. The welding gun 18 is fixedly installed on the end of the moving platform 17 near the pipe, or the welding gun 18 is fixedly installed on the end of the moving platform 17 near the pipe through an angle adjustment seat. The angle adjustment seat can realize the ±15° adjustment of the welding angle of the welding gun 18 to adapt to the welding requirements of flanges with different pipe diameters. A bolt II 35 is threadedly connected to the end of the moving platform 17 away from the welding gun 18. The end of the bolt II 35 is used to contact the outer wall of the pin rod 6 to fix the position of the moving platform 17 on the pin rod 6.

[0031] After the flange and pipe end face are aligned, the operator slides the moving platform 17 along the pin rod 6 to adjust the nozzle of the welding gun 18 to the joint between the pipe and the flange. Then, the bolt II 35 is tightened to fix the position of the moving platform 17. After that, the operator rotates the fixing ring seat 8 by hand or through the motor. The rotation of the fixing ring seat 8 will drive the pin rod 6 to rotate. The pin rod 6 drives the entire sleeve to rotate around the outer wall of the pipe through the limit stop 5. Since the sleeve contacts the pipe through the rolling wheel 4, the rotation resistance is very small. As the sleeve rotates, the welding gun 18 fixed on the moving platform 17 makes a circular motion around the weld, thereby performing circumferential welding on the joint between the pipe and the flange.

[0032] Reference Figure 6 A contact baffle 15 is slidably fitted on the outer wall of the positioning pin 14, and a helical spring 16 is fitted on the outer wall of the positioning pin 14. The two ends of the helical spring 16 are fixedly connected to the contact baffle 15 and the side of the sliding plate 10 that are close to each other through spring seats. The helical spring 16 is used to provide buffer when the flange abuts with the pipe end face to avoid the pipe or flange end face being squeezed and damaged due to excessive abutment force. Multiple auxiliary guide rods are also slidably provided on the sliding plate 10 around the positioning pin 14. One end of the auxiliary guide rod is fixedly connected to the contact baffle 15 to ensure that the flange end face is parallel and fits during abutment.

[0033] Reference Figure 2 , Figure 7 and Figure 8The welding device also includes an isolation mechanism for isolating the inner wall of the pipe and flange docking area, thereby improving the efficiency of air replacement. The isolation mechanism includes a mandrel 19 and movable seats I 20 and II 21 that slide on the outer wall of the mandrel 19. Movable seats I 20 and II 21 are both sleeved on the outer wall of the mandrel 19 and can slide along the axial direction of the mandrel 19.

[0034] Reference Figure 2 and Figures 7-11 The isolation mechanism also includes two rubber sealing rings 24, with a silicone fiberglass annular belt 25 fixedly connected between them. Multiple connecting rods 122 are rotatably connected to the outer walls of both the movable seat I 20 and the movable seat II 21. The connecting rods 122 on the movable seat I 20 and the movable seat II 21 are also evenly distributed circumferentially. The ends of the connecting rods 122 on the same side away from the spindle 19 are fixedly connected to the corresponding rubber sealing rings 24. Specifically, the connecting rod 122 connected to the movable seat I 20 is connected to one rubber sealing ring 24, and the connecting rod 122 connected to the movable seat II 21 is connected to another rubber sealing ring 24. A connecting rod II 23 is rotatably connected to the side of the connecting rod 122 closest to the spindle 19, and the other end of the connecting rod II 23 is rotatably connected to the outer wall of the spindle 19. Above, a protective shell is fixed to the outer wall of the mandrel 19. Multiple transmission gears 30 are rotatably connected to the protective shell via a base. Multiple racks 29 and 128 are fixed to the sides of the moving seats I 20 and II 21 that are close to each other. Both racks 29 and 128 extend into the protective shell and mesh with the transmission gears 30. The protective shell is used to shield welding spatter. Specifically, rack 128 is fixed on the moving seat II 21 and rack 29 is fixed on the moving seat I 20. The two are arranged opposite each other and mesh with the transmission gear 30 located between them. When the moving seat II 21 moves toward the moving seat I 20, rack 128 on the moving seat II 21 drives the transmission gear 30 to rotate. The transmission gear 30 then drives rack 229 to move toward the moving seat II 21, thereby realizing the opposite movement of the moving seats I 20 and II 21.

[0035] Reference Figures 7-11 The silicone fiberglass annular strip 25, together with the two rubber sealing rings 24 and the inner wall of the pipe and the inner wall of the flange, form a closed isolation chamber 32, which is located in the weld area between the pipe and the flange.

[0036] After the pipe and flange are connected, the mandrel 19 is inserted into the inside of the pipe and flange, so that the moving seat I 20 is located inside the pipe and the moving seat II 21 is located inside the flange. By driving the moving seat II 21 to move towards the moving seat I 20, the moving seats I 20 and II 21 move towards each other. During the movement, under the support and limiting action of the connecting rod II 23, the end of the connecting rod I 22 away from the mandrel 19 opens towards the inner wall of the pipe or flange until the two rubber sealing rings 24 are tightly abutted against the inner wall of the pipe and the inner wall of the flange, respectively. At this time, the silicone fiberglass ring 25 covers the gap between the pipe and the flange, thereby forming a sealed isolation chamber 32 in the weld area.

[0037] Reference Figure 11 To facilitate the replacement of gas in the isolation chamber 32, the mandrel 19 is provided with an exhaust channel 33 and an injection channel 34. Two flexible hoses 31 are fixed to the outer wall of the mandrel 19. The ends of the two flexible hoses 31 that are close to each other are connected to the exhaust channel 33 and the injection channel 34, respectively. The ends of the two flexible hoses 31 that are far from each other are fixed through a silicone fiberglass annular strip 25 and are connected to the isolation chamber 32. One end of the injection channel 34 is connected to an external gas source, such as an argon source. The end of the exhaust channel 33 that is far from the flexible hoses 31 is connected to the outside atmosphere to discharge the original gas in the isolation chamber 32.

[0038] When gas replacement is required, argon gas is injected into the isolation chamber 32 through the gas injection channel 34 and the corresponding flexible hose 31. As argon gas is continuously injected, the original air and other impurities in the isolation chamber 32 are discharged through the exhaust channel 33 and the corresponding flexible hose 31, thereby forming a high-purity argon gas protective environment in the weld area.

[0039] Reference Figure 7 and Figure 8 In order to achieve precise driving of the moving seat II 21, the outer wall of the spindle 19 is provided with a threaded section. A nut seat 26 is threaded on the threaded section of the spindle 19. A rotating ring 42 is rotatably connected to one side of the nut seat 26. Multiple support columns 27 are fixed to one side of the rotating ring 42. One end of each of the multiple support columns 27 is fixedly connected to one end of the moving seat II 21.

[0040] By rotating the nut seat 26, the nut seat 26 moves along the axial direction of the spindle 19 under the engagement of the threaded section on the outer wall of the spindle 19. The nut seat 26 pushes the moving seat II 21 to move through the support column 27. In order to ensure the smooth sliding of rack I 28 and rack II 29, multiple protrusions are fixed on the outer wall of the spindle 19. Rack I 28 is slidably connected to these protrusions, while rack II 29 is slidably connected to the outer wall of the spindle 19.

[0041] The device also includes a controller (not shown in the figure), which is electrically connected to the electric push rod I2, the electric push rod II13 and the external argon gas source control valve respectively. Through the preset program of the controller, the synchronous extension and retraction of the electric push rod I2 can be automatically controlled to clamp the pipeline, and the precise extension and retraction of the electric push rod II13 can be controlled to complete the flange positioning. At the same time, the argon gas source is controlled to fill the isolation chamber according to the set time sequence.

[0042] In another embodiment: Refer to Figure 12 and Figure 13 The welding device also includes a dust collection hood 36, which is fixedly sleeved on the outer wall of the welding gun 18 and close to one end of the welding gun 18. The top diameter of the dust collection hood 36 is smaller than the bottom diameter, and the whole is shaped like a trumpet with a smaller top and a larger bottom. An annular pipe 38 is fixedly fixed at the bottom of the dust collection hood 36, and a gas injection pipe 40 is fixedly inserted through the dust collection hood 36. The gas injection pipe 40 is connected to the annular pipe 38 and is used to inject gas into the annular pipe 38. The inner wall of the dust collection hood 36 is provided with a spiral guide groove 37, and the top of the annular pipe 38 is provided with multiple oblique holes 39. The orientation of these oblique holes 39 is the same as the spiral direction of the spiral guide groove 37. An exhaust pipe 41 is fixedly connected to the top of the dust collection hood 36 for exhausting gas. Multiple barbs are fixed in the spiral guide groove 37.

[0043] When the welding torch 18 is welding, compressed air or other cooling gas is injected into the annular pipe 38 through the gas injection pipe 40. The gas is ejected at a certain angle through the inclined hole 39 at the top of the annular pipe 38. Under the guidance of the spiral guide groove 37 on the inner wall of the dust collection hood 36, a high-speed rotating spiral airflow is formed. This rotating airflow creates a low-pressure zone in the central area at the bottom of the dust collection hood 36. The splashed metal droplets generated during the welding process are sucked into the dust collection hood 36 under the action of inertia and low pressure. The high-speed rotating airflow carries the metal droplets in centrifugal motion, causing them to collide with the inner wall of the spiral guide groove 37. Since the spiral guide groove 37 is provided with barbs, the metal droplets collide with the inner wall of the spiral guide groove 37 and the barbs. Due to the impact and cooling, the metal droplets quickly solidify and adhere to the barbs and the groove wall, thus being effectively captured.

[0044] A method for using a butt-welding device for a raised-face weld neck flange includes the following steps: S1. The operator places two interlocking semi-circular clamps 1 onto the outer wall of the pipe to be welded, and locks the movable ends of the two semi-circular clamps 1 with bolts, so that the two semi-circular clamps 1 merge to form a complete collar. Then, multiple electric push rods I2 are activated. The piston rods of the electric push rods I2 extend and push the clamping plate 3 fixed at its end toward the outer wall of the pipe until the rolling wheel 4 rotatably installed on the clamping plate 3 is tightly abutted against the outer wall of the pipe. Through the clamping force continuously applied by the electric push rods I2, the entire collar is stably fixed to the outer wall of the pipe. At the same time, since the rolling wheel 4 is in rolling contact with the outer wall of the pipe, the collar can still rotate circumferentially relative to the pipe when subjected to external force. S2. After the installation and fixing of the device are completed, the flange positioning and docking operation is performed. The operator passes the two pins 6 of the abutment mechanism through the outside of the pipe and through the limiting blocks 5 fixed on the inner wall of the two semi-annular clamps 1, so that the pins 6 can slide freely in the guide holes of the limiting blocks 5. At this time, the operator controls the extension and retraction of the piston rod of the electric push rod II 13. The electric push rod II 13 drives the sliding seat 12 to move in the strip guide groove 11 of the sliding plate 10. Since the sliding seat 12 is simultaneously slidingly engaged with the pins 6, the sliding plate 10 will generate axial displacement relative to the pins 6. Through this displacement, the positioning pin 14, which is integrally fixed on the sliding plate 10, moves to a position aligned with the flange hole on the flange to be welded. The operator puts the flange hole of the flange onto the positioning pin 14, so that the flange is accurately installed on one side of the sliding plate 10. The piston rods extend and retract at the same distance. At this time, the axis of the flange and the axis of the pipe are automatically in a coaxial state. Then, the operator pushes the fixed ring seat 8. The fixed ring seat 8 drives the two pin rods 6, the sliding plate 10 and the flange installed on the sliding plate 10 to move towards the pipe until the end face of the flange and the end face of the pipe come into contact with each other and achieve complete docking. During the process of the flange and the end face of the pipe coming into contact, the abutment baffle 15 sleeved on the positioning pin 14 compresses the helical spring 16. The helical spring 16 absorbs the impact force generated during docking through its own elastic deformation, avoiding damage to the end face of the flange and the pipe due to hard contact. After the end face of the flange and the end face of the pipe are docked, the operator tightens the bolt I7 on the limit block 5 so that the end of the bolt I7 abuts tightly against the outer wall of the pin rod 6, thereby fixing the position of the pin rod 6 and the entire abutment mechanism, and completing the precise docking and positioning of the flange and the pipe. S3. After the flange and pipeline are connected, gas isolation and protection are performed in the welding area. The operator inserts the mandrel 19 of the isolation mechanism into the pipeline or flange from the port, so that the movable seat I 20 on the mandrel 19 is located inside the pipeline and the movable seat II 21 is located inside the flange. The operator rotates the nut seat 26 on the threaded section of the mandrel 19. Under the action of the threaded engagement, the nut seat 26 moves axially along the mandrel 19. The nut seat 26 is rotatably connected to the rotating ring 42 and multiple support columns 27 fixed on the rotating ring 42. The moving seat II 21 is pushed to move towards the moving seat I 20. The rack I 28 on the moving seat II 21 moves together with the moving seat II 21. The rack I 28 drives the transmission gear 30 meshing with it to rotate. The transmission gear 30 then drives the rack II 29 meshing with it to move in the opposite direction. The rack II 29 drives the moving seat I 20 to move towards the moving seat II 21, thus realizing the opposite movement of the moving seats I 20 and II 21. During the opposite movement, the moving seats I 20 and II 21 respectively push the connecting rod I 22 that is rotatably connected to them. Supported and limited by the connecting rod II 23, which is rotatably connected to it, the end of connecting rod I 22 away from the spindle 19 gradually opens towards the inner wall of the pipe and the inner wall of the flange. As the moving seats I 20 and II 21 continue to move towards each other, the two rubber sealing rings 24 are pushed by connecting rod I 22 to fit tightly against the inner wall of the pipe and the inner wall of the flange, respectively. The silicone fiberglass annular strip 25 connected between the two rubber sealing rings 24 covers the gap between the pipe and the flange. At this time, the two rubber sealing rings 24, the silicone fiberglass annular strip 25, and... The inner wall of the pipe and the inner wall of the flange together form a closed isolation chamber 32. This isolation chamber 32 is located exactly in the weld area between the pipe and the flange. The operator connects the gas injection channel 34 in the mandrel 19 to the external argon gas source. The argon gas flows through the gas injection channel 34 and a flexible hose 31 into the isolation chamber 32. As the argon gas is continuously injected, the original air and other impurities in the isolation chamber 32 are discharged through another flexible hose 31 and the exhaust channel 33 in the mandrel 19, thereby forming a high-purity argon gas protective environment in the weld area. S4. After establishing the gas protection environment, welding operations are carried out. The operator slides the moving platform 17 along the pin rod 6, adjusts the nozzle of the welding gun 18 fixed on the moving platform 17 to the joint between the pipe and the flange, and then tightens the bolt II 35 on the moving platform 17 so that the end of the bolt II 35 abuts against the outer wall of the pin rod 6, fixing the position of the moving platform 17 on the pin rod 6. The operator starts the welding gun 18 to carry out the welding operation, and at the same time rotates the fixed ring seat 8 by hand. The fixed ring seat 8 drives the two pin rods 6 to rotate. The pin rods 6 drive the entire sleeve to rotate around the axis of the outer wall of the pipe through the limit stop 5. Since the sleeve contacts the outer wall of the pipe through the rolling wheel 4 on the clamping plate 3, and the rolling wheel 4 can rotate freely, the frictional resistance experienced by the sleeve during the rotation is small, and the rotation process is smooth and stable. As the sleeve rotates at a uniform speed, the welding gun 18 fixed on the moving platform 17 makes a circular motion around the weld between the pipe and the flange, thereby completing the continuous welding of the entire annular weld. S5. During the welding process, the dust collection hood 36 simultaneously collects spatter. The operator injects compressed air into the annular pipe 38 at the bottom of the dust collection hood 36 through the air injection pipe 40. The gas is ejected at a certain angle from multiple oblique holes 39 at the top of the annular pipe 38. The ejected gas forms a high-speed rotating spiral airflow under the guidance of the spiral guide groove 37 set in the inner wall of the dust collection hood 36. This rotating airflow creates a local low-pressure zone in the central area at the bottom of the dust collection hood 36. The spattered metal droplets generated during the welding process are attracted by inertia and the low-pressure zone. The metal droplets are drawn into the dust collection hood 36 and centrifugally propelled by the high-speed rotating airflow. The droplets impact the inner wall of the spiral guide groove 37, where they rapidly cool and solidify. They are then mechanically locked in place by the barbs fixed within the spiral guide groove 37, preventing them from escaping the dust collection hood 36. The gas inside the dust collection hood 36 is then discharged through the exhaust pipe 41 connected to its top. Through this process, the device completes the entire butt welding workflow, from the installation and fixing of pipes and flanges, precise docking, local gas protection, to welding operations and spatter collection.

[0045] However, as is well known to those skilled in the art, the working principles and wiring methods of electric actuators II13 and I2 are conventional methods or common knowledge, and will not be elaborated here. Those skilled in the art can make any selections according to their needs or convenience.

[0046] The accompanying drawings in this application are for illustrative purposes only. The dimensions and shapes of the components shown are not actual limitations but are merely schematic representations. In actual implementation, the components can be reasonably configured and adjusted according to specific needs and actual conditions.

[0047] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A butt-welding device for a raised-face weld neck flange, comprising: Two semi-annular clamps (1), the two semi-annular clamps (1) are hinged to each other, the movable ends of the two semi-annular clamps (1) are fixedly connected by bolts, and the two semi-annular clamps (1) form a collar after being combined, characterized in that it further includes: A clamping mechanism, located inside the collar, is used to install the collar onto the outer wall of the pipe; The abutting mechanism is located inside the collar and is used to align the end face of the flange with the end face of the pipe. The abutting mechanism includes a fixed ring seat (8) and two pins (6) fixed on one side of the fixed ring seat (8). An isolation mechanism is used to isolate the inner wall of the pipe and flange docking area. The isolation mechanism includes a mandrel (19) and movable seats I (20) and II (21) that are slidably disposed on the outer wall of the mandrel (19). The clamping mechanism fixes the collar to the outer wall of the pipe, the abutting mechanism aligns the flange with the end face of the pipe, and the isolation mechanism forms an isolation chamber (32) between the inner walls of the pipe and the flange.

2. The butt welding device for a raised-face necked butt welding flange according to claim 1, characterized in that, The clamping mechanism includes multiple electric push rods I (2) that are fixedly inserted through the collar. Each of the piston rods of the multiple electric push rods I (2) has a clamping plate (3) fixed at one end near the pipe. Each of the clamping plates (3) has a rolling wheel (4) rotatably mounted on one side near the pipe. The piston rod of the electric push rod I (2) pushes the clamping plate (3) close to the pipe, fixes the collar to the outer wall of the pipe, and enables the collar to rotate on the outer wall of the pipe through the rolling wheel (4).

3. The butt welding device for a raised-face necked butt welding flange according to claim 2, characterized in that, The abutting mechanism also includes two limiting blocks (5), which are fixed to the inner walls of the two semi-annular clamps (1) respectively. One end of each of the two pin rods (6) slides through the corresponding limiting blocks (5), and the limiting blocks (5) are bolted with bolts I (7) for abutting against the outer wall of the pin rods (6). The outer walls of both pins (6) are fitted with sliding plates (10), and the sliding plates (10) are provided with strip guide grooves (11). A sliding seat (12) is slidably connected in the strip guide grooves (11). The sliding seat (12) is slidably fitted on the outer wall of the pins (6) through the sliding groove and the slider. An electric push rod II (13) is fixed on the inner wall of the strip guide groove (11) near the pipe. One end of the piston rod of the electric push rod II (13) is fixedly connected to the sliding seat (12). A positioning pin (14) for inserting into the flange hole of the flange is fixed on the side of the sliding plate (10) near the semi-annular clamp (1). The sliding plate (10) is displaced relative to the pin rod (6) by the extension and retraction of the electric push rod II (13) until the positioning pin (14) is aligned with the flange hole of the flange. The flange is then installed on one side of the sliding plate (10), the fixing ring seat (8) is pushed to make the end face of the flange align with the end face of the pipe, and the bolt I (7) is tightened to position the pin rod (6).

4. The butt welding device for a raised-face necked butt welding flange according to claim 3, characterized in that, The outer wall of the pin rod (6) is slidably fitted with a moving platform (17), and the welding gun (18) is fixedly installed on the end of the moving platform (17) near the pipe. The end of the moving platform (17) away from the welding gun (18) is provided with a threaded hole, and a bolt II (35) for abutting against the outer wall of the pin rod (6) is screwed into the threaded hole. By adjusting the position of the moving platform (17), the welding gun (18) is moved to the weld seam between the pipe and the flange. The bolt II (35) is tightened to fix the position of the moving platform (17). The fixed ring seat (8) is rotated to drive the collar to rotate, so that the welding gun (18) can weld around the weld seam.

5. The butt welding device for a raised-face necked butt welding flange according to claim 4, characterized in that, The isolation mechanism also includes two rubber sealing rings (24) and a silicone fiberglass annular strip (25) fixed between the two rubber sealing rings (24). The outer walls of both the movable seat I (20) and the movable seat II (21) are rotatably connected to connecting rod I (22). The ends of multiple connecting rods I (22) located on the same side away from the spindle (19) are fixedly connected to the corresponding rubber sealing rings (24). The side of the connecting rod I (22) close to the spindle (19) is rotatably connected to connecting rod II (23). The end of the connecting rod II (23) away from the connecting rod I (22) is rotatably connected to the hinge seat fixed to the outer wall of the spindle (19). The outer wall of the spindle (19) is rotatably connected to a plurality of transmission gears (30) via a base. A plurality of racks II (29) and rack I (28) are fixed on the side of the moving seat I (20) and the moving seat II (21) that are close to each other. The side of the rack I (28) and the rack II (29) that are close to each other are meshed with the corresponding transmission gears (30).

6. The butt welding device for a raised-face necked butt welding flange according to claim 5, characterized in that, The isolation mechanism also includes an exhaust channel (33) and an injection channel (34) disposed within the spindle (19). Two flexible hoses (31) are fixed to the outer wall of the mandrel (19). The ends of the two flexible hoses (31) that are close to each other are connected to the exhaust channel (33) and the gas injection channel (34) respectively. The ends of the two flexible hoses (31) that are far apart from each other are fixed through the silicone fiberglass ring belt (25) and connected to the isolation chamber (32). One end of the gas injection channel (34) is used to connect to an external argon gas source. Argon gas is injected into the isolation chamber (32) through the gas injection channel (34) and the corresponding flexible hose (31), and the original gas in the isolation chamber (32) is discharged through the exhaust channel (33) and the corresponding flexible hose (31).

7. The butt welding device for a raised-face necked butt welding flange according to claim 6, characterized in that, The outer wall of the mandrel (19) is provided with a threaded section. The mandrel (19) is threaded with a nut seat (26) through the threaded section. A rotating ring (42) is rotatably connected to one side of the nut seat (26). A plurality of support columns (27) are fixed to one side of the rotating ring (42). One end of each of the support columns (27) is fixedly connected to one end of the movable seat II (21). By rotating the nut seat (26), the nut seat (26) moves axially along the spindle (19) and pushes the movable seat II (21) to move via the support column (27).

8. The butt welding device for a raised-face necked butt welding flange according to claim 7, characterized in that, It also includes a dust collection hood (36), which is fixedly sleeved on the outer wall of the welding gun (18) and close to one end of the welding gun (18) head. The top diameter of the dust collection hood (36) is smaller than the bottom diameter. The bottom of the dust collection hood (36) is fixed with an annular pipe (38), and an air injection pipe (40) connected to the annular pipe (38) is fixedly passed through the dust collection hood (36). The inner wall of the dust collection hood (36) is provided with a spiral guide groove (37). The top of the annular pipe (38) is provided with multiple oblique holes (39), and the orientation of the oblique holes (39) is the same as the spiral direction of the spiral guide groove (37). Multiple barbs are fixed in the spiral guide groove (37). The top of the dust collection hood (36) is fixedly connected with an exhaust pipe (41). Gas is injected into the annular pipe (38) through the gas injection pipe (40). The gas is ejected obliquely through the oblique hole (39) and forms a rotating airflow under the action of the spiral guide groove (37), which creates a low pressure at the bottom of the dust collection hood (36). Under the action of the rotating airflow, the metal droplets hit the inner wall and barbs of the spiral guide groove (37), cool and solidify rapidly, and adhere to the metal, thus being captured.

9. A butt welding device for a raised-face necked butt welding flange according to claim 8, characterized in that, The outer wall of the positioning pin (14) is slidably fitted with an abutment baffle (15), and the outer wall of the positioning pin (14) is fitted with a helical spring (16). The two ends of the helical spring (16) are respectively fixedly connected to the abutment baffle (15) and the sliding plate (10) on the side close to each other through spring seats. When the flange abuts against the end face of the pipe, the compression of the helical spring (16) causes the abutment baffle (15) to slide along the positioning pin (14) to provide clearance.

10. A method of using a welding apparatus for a raised-face weld neck flange, applied to the welding apparatus for a raised-face weld neck flange as described in claim 9, characterized in that... Includes the following steps: Two interlocking semi-circular clamps (1) are fitted onto the outer wall of the pipe and the movable end is locked to form a collar. The electric push rod I (2) is started to push the clamping plate (3) so that the rolling wheel (4) presses against the outer wall of the pipe, so that the collar can rotate circumferentially. Slide the two pins (6) through the limit block (5), and drive the sliding seat (12) to move in the strip guide groove (11) of the sliding plate (10) through the electric push rod II (13), so that the positioning pin (14) on the sliding plate (10) is aligned with the flange hole. After the flange is put on, push the fixing ring seat (8) to make the flange end face contact the pipe end face, abut the baffle (15) to compress the helical spring (16) to absorb the impact, and tighten the bolt I (7) to fix the pins (6). Insert the mandrel (19) into the pipe and flange, rotate the nut seat (26) to move the moving seat II (21) towards the moving seat I (20), drive the two to move towards each other through rack I (28), transmission gear (30) and rack II (29), push the rubber sealing ring (24) to fit against the inner wall of the pipe and flange, cover the gap with the silicone fiberglass ring belt (25) to form an isolation chamber (32), inject argon gas through the gas injection channel (34) and flexible hose (31), and exhaust the impurity gas through the exhaust channel (33); Slide the moving platform (17) along the pin rod (6) to adjust the welding gun (18) to the joint and fix it with bolt II (35). Rotate the fixed ring seat (8) to drive the sleeve to rotate around the pipeline axis and use the welding gun (18) to complete the continuous welding of the annular weld. Compressed air is injected into the annular pipe (38) through the air injection pipe (40). The gas is ejected through the inclined hole (39) and forms a rotating airflow under the guidance of the spiral guide groove (37). The splashed metal droplets are sucked into the dust collection hood (36) and cooled and solidified by impact. The gas is discharged through the exhaust pipe (41).

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