A welding device for large-diameter pipes
Patent Information
- Application Number
- CN202522382760.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-10
- Publication Date
- 2026-10-30
- Estimated Expiration
- 2035-11-10
AI Technical Summary
[0004]本实用新型要解决的技术问题是提供一种大口径管道的焊接装置，通过设置若干第二限位板组成漏斗状，便于第二管道进入第二限位板内，之后与第一管道进行对接，通过以上的设置可以解决管道对接时间较差，影响管道焊接效率的问题
[0016]上述方案中，通过设置第一固定板与第一管道进行相对固定后，移动第一限位板即可带动第二限位板和第三限位板绕着第四限位板的一端转动，使得若干第二限位板组成漏斗状，便于第二管道进入第二限位板内，之后与第一管道进行对接，提高第二管道和第一管道的对接效率，在第一管道和第二管道对接后启动管道内焊机即可将第一管道和第二管道进行焊接。
Smart Images
Figure CN224913861U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of pipeline welding technology, and in particular to a welding device for large-diameter pipelines. Background Technology
[0002] Large-diameter alloy pipes are industrial alloy steel pipes used for transporting oil, natural gas, coal gas, and water. They are characterized by being environmentally friendly, energy-saving, and resource-saving. According to the manufacturing process, these products are divided into hot-rolled (extruded) seamless steel pipes and cold-drawn (rolled) seamless steel pipes. Cold-drawn pipes include both round and shaped pipes.
[0003] Existing methods for using large-diameter alloy pipes involve transporting the pipes to the side of the pipe trench where outdoor pipes need to be laid, and then using a hoisting machine to lift the pipes into the trench. When welding two pipes together, a large-diameter pipe welding machine is first installed inside one pipe, and then workers pull the other hoisted pipe to move and connect it. During the connection process, due to the large size and weight of the large-diameter pipes, and the fact that the bottom of the pipe laying trench is often uneven and has water accumulation, it is difficult for workers to pull the pipes to connect, and the connection time is long, affecting the efficiency of pipe welding. Therefore, this utility model provides a welding device for large-diameter pipes to meet the requirements. Utility Model Content
[0004] The technical problem to be solved by this utility model is to provide a welding device for large-diameter pipes. By setting several second limiting plates to form a funnel shape, it is easy for the second pipe to enter the second limiting plate and then dock with the first pipe. The above setting can solve the problem of poor pipe docking time, which affects the pipe welding efficiency.
[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution:
[0006] A welding device for large-diameter pipes.
[0007] Two first fixed plates are rotatably connected at one end, and a first connecting plate is fixedly connected to the other end of each of the two first fixed plates. A second fixed plate is fixedly connected to one end of each of the two first connecting plates. A screw is movably sleeved in the middle of the two first connecting plates, and a nut is threaded to one end of the screw. Several annularly distributed movable frames are fixedly connected to the outer walls of the second fixed plate and the first fixed plate. A fourth limiting plate is fixedly connected to one end of the movable frame. A third limiting plate is rotatably connected to one end of the fourth limiting plate. A second limiting plate is fixedly connected to the other end of the third limiting plate. A first limiting plate is rotatably connected to one side of the second limiting plate. The first limiting plate slides through the third limiting plate and the fourth limiting plate and is slidably connected to the middle of the movable frame. A pipe welding machine is fixedly connected to one end of the inner cavity of the first pipe. The first pipe is connected to a second pipe. A positioning component is provided at the end of the first limiting plate, and the positioning component fixes the position of the first limiting plate.
[0008] Optionally, the positioning component includes a rotating shaft rotatably connected to the end of the first limiting plate, with two ends of the rotating shaft passing through the movable frame and fixedly connected to the outside of the movable frame via a second connecting plate. A third connecting plate is fixedly connected to the end of the second connecting plate, with one end of a spring fixedly connected to the third connecting plate, and the other end of the spring fixedly connected to a limiting rod. Limiting holes are provided in the middle of both the second and first fixed plates, and the end of the limiting rod passes through the third connecting plate and is movably engaged with the limiting hole.
[0009] Optionally, the first fixing plate and the second fixing plate have the same shape, the first fixing plate is an arc-shaped plate, and the two first fixing plates form a C-shape.
[0010] Optionally, both the fourth limiting plate and the third limiting plate are arc-shaped plates, and the third limiting plate and the fourth limiting plate form a C-shape, with the second limiting plate fitting against the outer wall of the second pipe.
[0011] Optionally, both the third limiting plate and the fourth limiting plate have holes in their middle portions, and the first limiting plate is disposed within the holes.
[0012] Optionally, the movable frame includes a fixed frame and two movable tracks, the two movable tracks being fixedly connected to both sides of the fixed frame, and the rotating shaft being slidably connected within the movable tracks.
[0013] Optionally, the third connecting plate is an arc-shaped plate, and there are two third connecting plates, which correspond to the first fixing plate.
[0014] Optionally, a plurality of anti-slip blocks are fixedly connected to the inner wall of the first fixing plate, and the anti-slip blocks are in contact with the outer wall of the first pipe.
[0015] Compared with the prior art, this utility model has at least the following beneficial effects:
[0016] In the above scheme, after the first fixed plate is relatively fixed to the first pipe, moving the first limiting plate can drive the second and third limiting plates to rotate around one end of the fourth limiting plate, so that several second limiting plates form a funnel shape, which facilitates the second pipe to enter the second limiting plate and then dock with the first pipe, thereby improving the docking efficiency of the second pipe and the first pipe. After the first pipe and the second pipe are docked, the pipe welding machine can be started to weld the first pipe and the second pipe.
[0017] The movable frame restricts the movement direction of the first limiting plate via a rotating shaft, allowing the third connecting plate to move the first limiting plate via the second connecting plate and the rotating shaft, which in turn causes the second limiting plate to rotate. The third connecting plate restricts the movement position of the limiting rod via a spring, allowing both the second and first fixed plates to limit the position of the limiting rod through limiting holes. This, in turn, restricts the position of the third connecting plate after it has moved, thus fixing the positions of the first and second limiting plates. Consequently, the position of the second limiting plate when it is open or closed is effectively fixed. When the second limiting plate is closed, it restricts the movement of the second pipe, facilitating the welding of the first and second pipes and improving the welding effect. Attached Figure Description
[0018] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments of the present invention and, together with the specification, further serve to explain the principles of the present invention and enable those skilled in the art to implement and use the present invention.
[0019] Figure 1 A three-dimensional structural diagram of a welding device for large-diameter pipelines;
[0020] Figure 2 A three-dimensional structural diagram showing the connection between the first fixed plate, the second fixed plate, and the movable frame;
[0021] Figure 3 for Figure 2 A magnified three-dimensional structural diagram at point A.
[0022] Figure label:
[0023] 1. First pipe; 2. First fixing plate; 3. Anti-slip block; 4. First connecting plate; 5. Screw; 6. Nut; 7. Second fixing plate; 8. Moving frame; 81. Fixing frame; 82. Moving track; 9. First limiting plate; 10. Second limiting plate; 11. Third limiting plate; 12. Fourth limiting plate; 13. Rotating shaft; 14. Second connecting plate; 15. Third connecting plate; 16. Spring; 17. Limiting rod; 18. Limiting hole; 19. Second pipe.
[0024] As shown in the figure, specific structures and devices are marked in the figure to clearly illustrate the structure of the embodiment of this utility model. However, this is only for illustrative purposes and is not intended to limit this utility model to this specific structure, device and environment. Those skilled in the art can adjust or modify these devices and environments according to specific needs. Detailed Implementation
[0025] The welding device for large-diameter pipes provided by this utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, to make the embodiments more detailed, the following embodiments are the best and preferred embodiments. For some known technologies, those skilled in the art can also use other alternative methods to implement the invention. Furthermore, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit this utility model.
[0026] It should be noted that the use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.
[0027] Generally, terms can be understood at least partly from their use in context. For example, depending at least partly on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood not necessarily to convey an exclusive set of factors, but rather, alternatively, depending at least partly on the context, to allow for the presence of other factors that are not necessarily explicitly described.
[0028] It is understood that the meanings of “on”, “above”, and “above” in this utility model should be interpreted in the broadest manner, such that “on” not only means “directly on” something, but also includes the meaning of being “on” something with an intervening feature or layer, and that “above” or “above” not only means “on” something, but also includes the meaning of being “on” something without an intervening feature or layer.
[0029] Furthermore, spatially related terms such as “below,” “under,” “lower,” “above,” and “upper” are used herein for convenience to describe the relationship of one element or feature to one or more other elements or features, as illustrated in the accompanying drawings. Spatially related terms are intended to cover different orientations in the use or operation of the device other than those depicted in the accompanying drawings. The device may be oriented in other ways, and the spatially related descriptive terms used herein can be interpreted similarly.
[0030] like Figures 1 to 3 As shown, an embodiment of this utility model provides a welding device for a large-diameter pipe, including two first fixing plates 2 installed on the outer wall of a first pipe 1. One end of the two first fixing plates 2 is rotatably connected, and the other end of each of the two first fixing plates 2 is fixedly connected to a first connecting plate 4. One end of each of the two first connecting plates 4 is fixedly connected to a second fixing plate 7. A screw 5 is movably sleeved in the middle of the two first connecting plates 4, and a nut 6 is threadedly connected to one end of the screw 5. Several annularly distributed movable frames 8 are fixedly connected to the outer walls of the second fixing plates 7 and the first fixing plates 2. One end of each movable frame 8 is fixedly connected to one end of a fourth limiting plate 12. The other end of the fourth limiting plate 12 is rotatably connected to one end of a third limiting plate 11. The other end of the third limiting plate 11 is fixedly connected to a second limiting plate 10. One side of the second limiting plate 10 is rotatably connected to a first limiting plate 9. The first limiting plate 9 slides through the third limiting plate 11 and the fourth limiting plate 12 and is slidably connected to the middle of the movable frame 8.
[0031] A pipe welding machine is fixedly connected to one end of the inner cavity of the first pipe 1, and a second pipe 19 is connected to one end of the first pipe 1. In use, two first fixing plates 2 are installed on the outer wall of the first pipe 1. One end of the two first fixing plates 2 is rotatably connected, and the other end of each of the two first fixing plates 2 is fixedly connected to a first connecting plate 4. One end of each of the two first connecting plates 4 is fixedly connected to a second fixing plate 7. A screw 5 is movably sleeved in the middle of the two first connecting plates 4, and a nut 6 is threaded to one end of the screw 5. This allows the first fixing plate 2 to be fixed relative to the second fixing plate 7 through the first connecting plate 4. The positions of the two first connecting plates 4 are fixed by the screw 5 and the nut 6, thereby fixing the position of the first fixing plate 2 after it is attached to the first pipe 1, and also fixing the position of the second fixing plate 7, which facilitates the use of the device. Several annularly distributed movable frames 8 are fixedly connected to the outer walls of the second fixed plate 7 and the first fixed plate 2, so that the two ends of the movable frames 8 are respectively fixed to the first fixed plate 2 and the second fixed plate 7, thereby fixing the relative positions of the first fixed plate 2, the second fixed plate 7 and the movable frames 8 and making the connection tight. A fourth limiting plate 12 is fixedly connected to one end of the movable frame 8, a third limiting plate 11 is rotatably connected to one end of the fourth limiting plate 12, a second limiting plate 10 is fixedly connected to one end of the third limiting plate 11, and a first limiting plate 9 is rotatably connected to one side of the second limiting plate 10. The first limiting plate 9 slides through the third limiting plate 11 and the fourth limiting plate 12 and is slidably connected to the middle of the movable frame 8, so that the movable frame 8 fixes the position of the fourth limiting plate 12, so that the fourth limiting plate 12 restricts the rotation position of the third limiting plate 11 and the second limiting plate 10, thereby restricting the movement position of the first limiting plate 9. In use, after the first fixing plate 2 is relatively fixed to the first pipe 1, moving the first limiting plate 9 will drive the second limiting plate 10 and the third limiting plate 11 to rotate around one end of the fourth limiting plate 12, thereby making several second limiting plates 10 form a funnel shape, which facilitates the second pipe 19 to enter the second limiting plate 10 and then dock with the first pipe 1, improving the docking efficiency of the second pipe 19 and the first pipe 1. A pipe welding machine is fixedly connected to one end of the inner cavity of the first pipe 1, and the second pipe 19 is docked at one end of the first pipe 1, so that after the first pipe 1 and the second pipe 19 are docked, the pipe welding machine can be started to weld the first pipe 1 and the second pipe 19. A positioning component is provided at one end of the first limiting plate 9, which is used to fix the position of the first limiting plate 9, so that the position after the first limiting plate 9 drives the second limiting plate 10 and the third limiting plate 11 to move is fixed, thereby allowing the second limiting plate 10 to remain open, which facilitates the docking of the first pipe 1 and the second pipe 19.
[0032] As one implementation method in this embodiment, such as Figures 1 to 3As shown, a positioning component is provided at one end of the first limiting plate 9. The positioning component is used to fix the position of the first limiting plate 9. The positioning component includes a rotating shaft 13 rotatably connected to the end of the first limiting plate 9 located at the movable frame 8. Both ends of the rotating shaft 13 pass through the movable frame 8 and are fixedly connected to one end of the second connecting plate 14. The other end of the second connecting plate 14 is fixedly connected to a third connecting plate 15. One end of the spring 16 is fixedly connected to the third connecting plate 15. The other end of the spring 16 is fixedly connected to a limiting rod 17. Limiting holes 18 are opened in the middle of the second fixing plate 7 and the first fixing plate 2. One end of the limiting rod 17 passes through the third connecting plate 15 and is movably engaged with the limiting hole 18. The first fixing plate 2 and the second fixing plate 7 have the same shape. The first fixing plate 2 is an arc-shaped plate. The two first fixing plates 2 form a C-shape. The fourth limiting plate 12 and the third limiting plate 11 are both arc-shaped plates. The third limiting plate 11 and the fourth limiting plate 12 form a C-shape. The second limiting plate 10 is fitted to the outer wall of the second pipe 19. The third limiting plate 11 and the fourth limiting plate 12 are both provided with holes in the middle, and the first limiting plate 9 is disposed in the hole. The movable frame 8 includes a fixed frame 81 and two movable rails 82. The two movable rails 82 are respectively fixedly connected to both sides of the fixed frame 81, and the rotating shaft 13 is slidably connected in the movable rails 82.
[0033] The third connecting plate 15 is an arc-shaped plate. There are two third connecting plates 15, which correspond to the first fixed plate 2. Several anti-slip blocks 3 are fixedly connected to the inner wall of the first fixed plate 2. The anti-slip blocks 3 are in contact with the outer wall of the first pipe 1. The positioning assembly includes a rotating shaft 13 rotatably connected to one end of the first limiting plate 9. The two ends of the rotating shaft 13 pass through the movable frame 8 and are fixedly connected to the outside of the movable frame 8. The third connecting plate 15 is fixedly connected to one end of the second connecting plate 14. This allows the movable frame 8 to restrict the movement direction of the first limiting plate 9 through the rotating shaft 13. The third connecting plate 15 drives the first limiting plate 9 to move through the second connecting plate 14 and the rotating shaft 13, thereby driving the second limiting plate 10 to rotate. One end of a spring 16 is fixedly connected to one end of the third connecting plate 15, and the other end of the spring 16 is fixedly connected to a limiting rod 17. Limiting holes 18 are opened in the middle of the second fixing plate 7 and the first fixing plate 2. One end of the limiting rod 17 passes through the third connecting plate 15 and is movably engaged with the limiting hole 18, so that the third connecting plate 15 restricts the movement of the limiting rod 17 through the spring 16, and the second fixing plate 7 and the first fixing plate 2 can both restrict the position of the limiting rod 17 through the limiting hole 18, thereby restricting the position of the third connecting plate 15 after movement, so that the positions of the first limiting plate 9 and the second limiting plate 10 after movement are fixed, and thus the positions of the second limiting plate 10 when opening and closing can be effectively fixed, which facilitates the use of the device.
[0034] The first fixing plate 2 and the second fixing plate 7 have the same shape. The first fixing plate 2 is an arc-shaped plate, and the two first fixing plates 2 form a C-shape, which makes the first fixing plate 2 fit the first pipe 1 better. This allows the first fixing plate 2 to be adapted to multiple sizes of first pipe 1, thereby improving the practicality of the device. The fourth limiting plate 12 and the third limiting plate 11 are both arc-shaped plates, and the third limiting plate 11 and the fourth limiting plate 12 form a C-shape. This ensures that when the second pipe 19 enters the second limiting plate 10 and moves towards the first pipe 1 to dock, it will not collide with the rotating shaft of the third limiting plate 11 and the fourth limiting plate 12. This ensures that the rotating shaft of the third limiting plate 11 and the fourth limiting plate 12 can be used for a long time and is not easily damaged.
[0035] The second limiting plate 10 is attached to the outer wall of the second pipe 19. Holes are provided in the middle of the third limiting plate 11 and the fourth limiting plate 12, and the first limiting plate 9 is placed inside the holes. This allows the second limiting plate 10 to be retracted and attached to the second pipe 19 after the second pipe 19 and the first pipe 1 are connected, thus restricting the movement of the second pipe 19. This facilitates welding of the first pipe 1 and the second pipe 19 and improves the welding effect. The movable frame 8 includes a fixed frame and two movable rails, which are fixedly connected to both sides of the fixed frame. The rotating shaft 13 is slidably connected within the movable rails. The movable frame 8 provides a good limiting effect on the rotating shaft 13. The third connecting plate 15 is an arc-shaped plate, and there are two third connecting plates 15. The third connecting plate 15 corresponds to the first fixed plate 2, so that when the third connecting plate 15 moves, it drives several first limiting plates 9 through the second connecting plate 14 to facilitate the operation of the moving device. Several anti-slip blocks 3 are fixedly connected to the inner wall of the first fixed plate 2. The anti-slip blocks 3 are attached to the outer wall of the first pipe 1, so that the first fixed plate 2 and the first pipe 1 are better attached and fastened through the anti-slip blocks 3, thereby improving the relative positional stability of the first fixed plate 2 and the first pipe 1.
[0036] The working principle of the technical solution provided by this utility model is as follows:
[0037] In use, the first fixing plate 2 is connected to the first pipe 1. The first fixing plate 2, the first connecting plate 4, and the second fixing plate 7 are fixed relative to each other. The positions of the two first connecting plates 4 are fixed by screws 5 and nuts 6, thereby fixing the position of the first fixing plate 2 after it is attached to the first pipe 1, fixing the position of the second fixing plate 7, and making it easy to disconnect the connection between the first fixing plate 2 and the first pipe 1 for convenient use. The two ends of the movable frame 8 are respectively fixed relative to the first fixing plate 2 and the second fixing plate 7, fixing the relative positions of the first fixing plate 2, the second fixing plate 7, and the movable frame 8 and making the connection tight. The position of the fourth limiting plate 12 is fixed by the movable frame 8. The fourth limiting plate 12 restricts the rotational position of the third limiting plate 11 and the second limiting plate 10, thereby restricting the movement position of the first limiting plate 9 by the moving frame 8. After the first fixing plate 2 is relatively fixed to the first pipe 1, moving the first limiting plate 9 can drive the second limiting plate 10 and the third limiting plate 11 to rotate around one end of the fourth limiting plate 12, so that several second limiting plates 10 form a funnel shape, which facilitates the second pipe 19 to enter the second limiting plate 10 and then dock with the first pipe 1, improving the docking efficiency of the second pipe 19 and the first pipe 1. After the first pipe 1 and the second pipe 19 are docked, the pipe welding machine can be started to weld the first pipe 1 and the second pipe 19.
[0038] The movable frame 8 restricts the movement direction of the first limiting plate 9 through the rotating shaft 13, so that the third connecting plate 15 drives the first limiting plate 9 to move through the second connecting plate 14 and the rotating shaft 13, and drives the second limiting plate 10 to rotate. The third connecting plate 15 restricts the movement position of the limiting rod 17 through the spring 16, so that the second fixing plate 7 and the first fixing plate 2 can both restrict the position of the limiting rod 17 through the limiting hole 18, thereby restricting the position of the third connecting plate 15 after movement, so that the positions of the first limiting plate 9 and the second limiting plate 10 after movement are fixed, and thus the position of the second limiting plate 10 when it is open and closed can be effectively fixed. Therefore, when the second limiting plate 10 is closed, the second limiting plate 10 restricts the movement of the second pipe 19, which facilitates the welding of the first pipe 1 and the second pipe 19 and improves the welding effect.
[0039] This utility model encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this utility model. To provide the public with a thorough understanding of this utility model, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand this utility model even without these detailed descriptions. Furthermore, to avoid unnecessary confusion regarding the essence of this utility model, well-known methods, processes, procedures, components, and circuits are not described in detail.
[0040] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.
Claims
1. A welding device for a large-diameter pipe, comprising two first fixing plates installed on the outer wall of a first pipe, characterized in that, Two first fixed plates are rotatably connected at one end, and a first connecting plate is fixedly connected to the other end of each of the two first fixed plates. A second fixed plate is fixedly connected to one end of each of the two first connecting plates. A screw is movably sleeved in the middle of the two first connecting plates, and a nut is threaded to one end of the screw. Several annularly distributed movable frames are fixedly connected to the outer walls of the second fixed plate and the first fixed plate. A fourth limiting plate is fixedly connected to one end of the movable frame. A third limiting plate is rotatably connected to one end of the fourth limiting plate. A second limiting plate is fixedly connected to the other end of the third limiting plate. A first limiting plate is rotatably connected to one side of the second limiting plate. The first limiting plate slides through the third limiting plate and the fourth limiting plate and is slidably connected to the middle of the movable frame. A pipe welding machine is fixedly connected to one end of the inner cavity of the first pipe. The first pipe is connected to a second pipe. A positioning component is provided at the end of the first limiting plate, and the positioning component fixes the position of the first limiting plate.
2. The welding apparatus for large-diameter pipes according to claim 1, characterized in that, The positioning assembly includes a rotating shaft rotatably connected to the end of the first limiting plate. The two ends of the rotating shaft pass through the movable frame and are fixedly connected to the outside of the movable frame. A third connecting plate is fixedly connected to the end of the second connecting plate. One end of a spring is fixedly connected to the third connecting plate. The other end of the spring is fixedly connected to a limiting rod. Limiting holes are opened in the middle of both the second and first fixed plates. The end of the limiting rod passes through the third connecting plate and is movably engaged with the limiting hole.
3. The welding apparatus for large-diameter pipes according to claim 1, characterized in that, The first fixing plate and the second fixing plate have the same shape. The first fixing plate is an arc-shaped plate, and the two first fixing plates form a C-shape.
4. The welding apparatus for large-diameter pipes according to claim 1, characterized in that, Both the fourth limiting plate and the third limiting plate are arc-shaped plates, and the third limiting plate and the fourth limiting plate form a C-shape. The second limiting plate is in contact with the outer wall of the second pipe.
5. The welding apparatus for large-diameter pipes according to claim 1, characterized in that, Both the third limiting plate and the fourth limiting plate have holes in their middle portions, and the first limiting plate is disposed within the holes.
6. The welding apparatus for large-diameter pipes according to claim 2, characterized in that, The mobile frame includes a fixed frame and two moving tracks. The two moving tracks are respectively fixedly connected to both sides of the fixed frame, and the rotating shaft is slidably connected within the moving tracks.
7. The welding apparatus for large-diameter pipes according to claim 2, characterized in that, The third connecting plate is an arc-shaped plate, and there are two third connecting plates, which correspond to the first fixing plate.
8. The welding apparatus for large-diameter pipes according to claim 1, characterized in that, The inner wall of the first fixing plate is fixedly connected with a plurality of anti-slip blocks, which are in contact with the outer wall of the first pipe.