A valve flange-pipeline welding device and welding method

Abstract

The present invention relates to the technical field of valve flange welding, and discloses a valve flange-pipe welding device and a welding method. It includes a welding platform, and also includes a distance adjusting piece and a welding machine. The distance adjusting piece and the welding machine are both installed on the welding platform. The distance adjusting piece is connected to two mirror-imaged pipe clamp modules, and the two pipe clamp modules are fixed on the pipeline body. The locking and guiding components are used to change the layout position of the welding platform on the pipeline body and lock the position of the welding platform. The lifting screw is installed on the welding platform. The lifting screw is connected to the lifting platform. The lifting platform is hinged with a cradle. An angle adjustment push rod is hinged between the cradle and the lifting platform. The guide arc groove is provided on the cradle. When the present invention is working, the device can automatically complete the welding operation of the flange on the pipeline through the arrangement of the arc frame, the slider, and the two welding gun bodies. Through the realization of the above-mentioned automatic welding effect, the automation degree, welding precision and welding efficiency of the device can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of valve flange welding, in particular to a valve flange-pipeline welding device and a welding method. Background Art

[0002] The following problems often occur during manual welding of flanges and steel pipes: 1. Low welding efficiency; 2. The flanges and steel pipes need to be fixed before welding, and manual alignment is required. In response to the problem of low manual welding efficiency, automatic welding equipment has been proposed to increase the efficiency of flange welding. However, before welding, the automatic welding equipment also requires manual alignment and fixing of the flanges and steel pipes. This process is generally achieved with the help of auxiliary structures for welding, and can be fixed by brackets, etc. However, because mechanical structures are generally used for fixing, there are many structures for fixing.

[0003] In the prior art, a patent document with publication number CN114799707A discloses a portable flange welding device for chemical pipeline installation engineering, comprising: a main body, which is constructed as a sealed cylindrical shape with a cylindrical cavity arranged inside, a flange fixing part and a steel pipe fixing part arranged on the main body, the flange fixing part comprises a cross frame fixedly sleeved on the main body, and moving rods are slidably arranged on the end faces of the four legs of the cross frame, and limited short columns are fixedly arranged on the end faces of the four moving rods away from the cross frame and close to the main body. The above device can realize the rapid fixation of the flange and the steel pipe; and it is faster and more effective and suitable for different specifications and is easy to carry as a whole. However, when using the above device, on the one hand, it cannot realize the automatic welding operation of the flange on the pipeline, and on the other hand, it is not convenient to realize the multi-angle fixing and multi-angle connection operation of the flange on the pipeline body, and then it is not convenient for the precise positioning welding of the flange. Based on this, the present invention provides a valve flange-pipeline welding device and a welding method to solve the technical problems raised in the above background technology. Summary of the invention

[0004] The object of the present invention is to provide a valve flange-pipe welding device and a welding method, which solves the problem that the existing device proposed in the background technology cannot realize the automatic welding operation of the flange on the pipeline when in use, and is not convenient for realizing the multi-angle fixing and multi-angle connection operation of the flange on the pipeline body, and then is not convenient for the precise positioning welding of the flange. When the present invention is working, through the arrangement of the arc frame, the slider, and the two welding gun bodies, the device can automatically complete the welding operation of the flange on the pipeline. Through the realization of the above-mentioned automatic welding effect, the automation degree, welding precision and welding efficiency of the device are effectively improved. Through the arrangement of structures such as the cradle and the clamping parts, the multi-angle fixing of the flange on the pipeline body can be realized, and then the precise positioning welding of the flange is convenient. Moreover, through the structural arrangement of the device, the device is suitable for the connection and welding operations of multi-specification pipelines and multi-specification flanges. In order to solve the above-mentioned technical problems, the present invention provides the following technical solutions:

[0005] A valve flange-pipe welding device, comprising a welding platform, and also comprising:

[0006] A distance adjusting member and a welding machine, both of which are installed on a welding platform, and the distance adjusting member is drivingly connected to two mirror-imaged pipe clamp modules, and the two pipe clamp modules are fixed on the pipeline body;

[0007] The locking and guiding component is used to change the layout position of the welding station on the pipeline body and lock the position of the welding station;

[0008] A lifting screw rod is installed on the welding platform, the lifting screw rod is connected to the lifting platform in a transmission manner, a cradle is hinged on the lifting platform, and an angle adjustment push rod is hinged between the cradle and the lifting platform;

[0009] A guide arc groove is provided on the cradle, the inner wall of the guide arc groove is slidably connected with a slide, an arc frame driven by a motor c is mounted on the slide, the motor c is mounted on the cradle, and a transfer seat driven by a transmission worm is rotatably connected to the arc frame;

[0010] A clamping component is installed on the transfer seat and clamps the valve flange body;

[0011] Two welding gun assemblies are installed at both ends of the arc frame and connected to the welding machine.

[0012] Preferably, the pipe clamp module includes an outer clamp seat and an inner clamp seat, both of which are slidably connected to the welding table, a group of pressure sensors are installed between the relative surfaces of the outer clamp seat and the inner clamp seat, the outer clamp seat is driven by a distance adjusting piece, and four regularly distributed universal clamp beads are embedded on the inner clamp seat.

[0013] Preferably, the distance adjusting member includes a clamping screw a which is rotatably connected between the inner surfaces of the welding platform and driven by a motor, and the clamping screw a is mirror-arranged with a positive thread portion a and a negative thread portion a, and the positive thread portion a and the negative thread portion a are respectively transmission-connected to the outer clamping seats in the two pipe clamp modules.

[0014] Preferably, the locking and guiding components include a motor a installed on the welding table, a sleeve rotatably connected to the welding table, and a transmission seat slidably connected to the welding table, the output shaft end and the sleeve of the motor a are fixedly mounted with driven bevel gears, the two driven bevel gears are meshed with each other, a rotating shaft is fixedly mounted on the top surface of the transmission seat, the rotating shaft is transmission-connected to the sleeve, a pressure spring is provided on the rotating shaft and the position corresponding to the sleeve and the transmission seat, and the inner wall of the transmission seat is rotationally connected with a transmission wheel driven by the motor b.

[0015] Preferably, an axis groove with openings at both ends and slidably connected to the rotating shaft is fixedly provided inside the sleeve, the cross-sections of the axis groove and the rotating shaft are both regular polygons, and the axial direction of the rotating shaft is perpendicular to the axial direction of the pipe body.

[0016] Preferably, a toothed ring is fixedly mounted on the arc frame, a driving gear is fixedly mounted on the output shaft end of the motor c, the driving gear is transmission-connected with the toothed ring, the full arc of the toothed ring is 190°, the full arc of the guide arc groove is 250°, and the axis of the toothed ring is in the same straight line as the rotation axis of the guide arc groove and the transfer seat.

[0017] Preferably, the clamping component includes a clamping screw b rotatably connected to the indexing seat and a group of guide rods fixed to the bottom surface of the indexing seat, the clamping screw b is symmetrically provided with a positive thread portion b and a negative thread portion b, the positive thread portion b and the negative thread portion are both transmission-connected with a clamping seat, the clamping seat is slidably connected to the guide rod, and a group of clamps for clamping the valve flange body are provided on the outer side of the clamping seat, a connecting rod is hinged between each of the clamps and the relative surfaces of the two clamping seats, and a pressure block is installed on each clamp.

[0018] Preferably, the welding gun assembly includes a universal rocker ball embedded in an arc frame, a connecting tube is installed at the bottom end of the universal rocker ball, a welding gun body is clamped on the inner wall of the connecting tube, the welding gun body is connected to the welding machine through a pipeline, and a locking corner piece for limiting the angle of the universal rocker ball is threadedly installed on the arc frame.

[0019] Preferably, a driven gear connected to the transmission worm is installed on the indexing seat.

[0020] The present invention also proposes a welding method for a valve flange-pipeline welding device, comprising the following steps:

[0021] SS01, preset, before welding, the welding platform is mounted on the pipeline body, after the welding platform is arranged, the position of the welding platform on the pipeline body is adjusted according to the position of the welding port of the valve flange body, and finally the axis of the arc frame and the axis of the welding port of the valve flange body are in the same straight line, after the arc frame position is adjusted, the position of the welding platform is locked by the transmission wheel;

[0022] SS02, fixation, after step SS01, fix the valve flange body on the transfer seat by means of the clamping component. After the valve flange body is fixed, adjust the layout height and layout angle of the arc frame so that the valve flange body is aligned with the welding port and the bottom end of the valve flange body is tightly fitted with the welding port;

[0023] SS03, welding, after step SS02, the motor c drives the two welding gun bodies to rotate 185 degrees counterclockwise along the axis where the axis of the indexing seat is located, and then completes the welding operation of the valve flange body on the pipeline body.

[0024] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0025] 1. When the present invention is working, the arc frame, the slider, and the two welding gun bodies are arranged so that the device can automatically complete the welding operation of the flange on the pipeline. By realizing the above-mentioned automatic welding effect, the automation degree, welding precision and welding efficiency of the device can be effectively improved. By arranging structures such as the cradle and the clamping parts, the multi-angle fixation of the flange on the pipeline body can be realized, which is convenient for the precise positioning welding of the flange. Moreover, through the structural arrangement of the device, the device is suitable for the connection and welding operations of pipelines of multiple specifications and flanges of multiple specifications.

[0026] 2. Before the welding operation of the present invention, the welding platform is mounted on the pipeline body. After the welding platform is arranged, the position of the welding platform on the pipeline body is adjusted according to the position of the welding port of the valve flange body, and finally the axis of the arc frame and the axis of the welding port of the valve flange body are made to be in the same straight line. After the position of the arc frame is adjusted, the position of the welding platform is locked by the transmission wheel. After locking, the valve flange body is fixed on the transfer seat by the clamping component. After the valve flange body is fixed, the arrangement height and arrangement angle of the arc frame are adjusted to align the valve flange body with the welding port and make the bottom end of the valve flange body fit tightly with the welding port. During welding, the motor C drives the two welding gun bodies to rotate 185° counterclockwise along the axis where the axis of the transfer seat is located, and then completes the welding operation of the valve flange body on the pipeline body. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of a valve flange-pipeline welding device;

[0028] Figure 2 It is a schematic diagram of the structure of the soldering station and the motor;

[0029] Figure 3 for Figure 2 A schematic diagram of the local enlarged structure at point A in the middle;

[0030] Figure 4 It is a schematic diagram of the structure of the welding machine and the universal clamp;

[0031] Figure 5 for Figure 4 A schematic diagram of the local enlarged structure at B in the middle;

[0032] Figure 6 It is a structural diagram of the slide and the cradle;

[0033] Figure 7 for Figure 6 A schematic diagram of the local enlarged structure at C in the middle;

[0034] Figure 8 It is a structural schematic diagram of the arc frame and the clamp;

[0035] Fig. 9 for Figure 8 A schematic diagram of the local enlarged structure at D in the middle;

[0036] Fig.10 It is a structural diagram of the universal rocking ball and arc frame;

[0037] Fig.11 It is a structural diagram of the valve flange body.

[0038] Among them: 1. welding table; 2. motor; 3. welding machine; 4. pipeline body; 5. lifting screw; 6. lifting platform; 7. cradle; 8. angle adjustment push rod; 9. guide arc groove; 10. slide; 11. motor c; 12. arc frame; 13. transmission worm; 14. indexing seat; 15. valve flange body; 16. outer clamp seat; 17. inner clamp seat; 18. pressure sensor; 19. universal clamp ball; 20. clamping screw a; 21. motor a; 22. bushing; 23. transmission seat; 24. rotating shaft; 25. pressure spring; 26. motor b; 27. transmission wheel; 28. missing gear ring; 29. ​​clamping screw b; 30. guide rod; 31. clamping seat; 32. clamp; 33. connecting rod; 34. universal rocking ball; 35. connecting pipe; 36. welding gun body; 37. locking angle piece; 38. pressure block. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] See also Figure 1-11 , a valve flange-pipe welding device, comprising a welding platform 1, and also comprising:

[0041] The distance adjusting member and the welding machine 3 are both installed on the welding platform 1. The distance adjusting member is transmission-connected to two mirror-image-arranged pipe clamp modules, and the two pipe clamp modules are fixed on the pipeline body 4.

[0042] The distance adjusting member includes a clamping screw a20 which is rotatably connected between the inner surfaces of the welding platform 1 and driven by the motor 2. The clamping screw a20 is mirror-imaged with a positive thread portion a and a negative thread portion a. The positive thread portion a and the negative thread portion a are respectively connected to the outer clamping seats 16 in the two pipe clamp modules.

[0043] By setting the positive thread portion a and the negative thread portion a, the two outer clamping seats 16 can be synchronously moved closer to each other or moved away from each other, and the distance between the two outer clamping seats 16 can be quickly changed by moving the two outer clamping seats 16 closer to each other or away from each other.

[0044] By changing the distance between the two outer clamping seats 16, the pipe body 4 to be welded can be effectively clamped.

[0045] By setting the two pipe clamp modules, the layout position of the welding platform 1 on the pipe body 4 is effectively limited;

[0046] The pipe clamp module includes an outer clamp seat 16 and an inner clamp seat 17, both of which are slidably connected to the welding platform 1, and a group of pressure sensors 18 are installed between the opposite surfaces of the outer clamp seat 16 and the inner clamp seat 17. The outer clamp seat 16 is driven by a distance adjusting member, and four regularly distributed universal clamp beads 19 are embedded on the inner clamp seat 17;

[0047] The universal clamp bead 19 is made of steel. Through the setting of the universal clamp bead 19, on the one hand, the welding platform 1 can be displaced left and right along the axis direction of the pipeline body 4, and the distance between the welding port of the welding platform 1 and the valve flange body 15 can be changed through the displacement of the welding platform 1. On the other hand, through the setting of the universal clamp bead 19, the welding platform 1 can be rotated at a set angle with the axis of the pipeline body 4 as the axis, thereby changing the layout position of the welding platform 1 on the pipeline body 4;

[0048] By setting the universal clamp bead 19, the valve flange body 15 can finally be quickly coaxial with the welding port of the valve flange body 15;

[0049] The locking and guiding component is used to change the layout position of the welding platform 1 on the pipeline body 4 and lock the position of the welding platform 1;

[0050] The locking and guiding components include a motor a21 mounted on the welding platform 1, a sleeve 22 rotatably connected to the welding platform 1, and a transmission seat 23 slidably connected to the welding platform 1. Driven bevel gears are fixedly mounted on the output shaft end of the motor a21 and the sleeve 22, and the two driven bevel gears are meshed with each other. A rotating shaft 24 is fixedly mounted on the top surface of the transmission seat 23, and the rotating shaft 24 is transmission-connected to the sleeve 22.

[0051] The shaft sleeve 22 is fixedly provided with a shaft groove with both ends opened and slidably connected to the shaft 24. The cross sections of the shaft groove and the shaft 24 are both regular polygons. The axis direction of the shaft 24 is perpendicular to the axis direction of the pipe body 4.

[0052] The shaft groove and the regular polygonal cross section of the shaft 24 are arranged so that when the shaft 24 moves up and down, the shaft sleeve 22 can continuously drive the shaft 24;

[0053] By setting the transmission wheel 27, the layout position of the welding station 1 on the pipeline body 4 can be electrically switched;

[0054] When the welding platform 1 needs to be rotated along the axis direction of the pipe body 4, the axis of the transmission wheel 27 is in the same direction as the axis direction of the pipe body 4; when the welding platform 1 needs to be moved along the axis direction of the pipe body 4, the axis of the transmission wheel 27 is perpendicular to the axis direction of the pipe body 4;

[0055] A pressure spring 25 is sleeved on the rotating shaft 24 and corresponds to the position between the shaft sleeve 22 and the transmission seat 23. The inner wall of the transmission seat 23 is rotatably connected to a transmission wheel 27 driven by a motor b26.

[0056] By setting the pressure spring 25, the transmission wheel 27 is in close contact with the pipeline body 4;

[0057] A lifting screw rod 5 is installed on the welding platform 1, and a lifting platform 6 is connected to the lifting screw rod 5 in a transmission manner. A cradle 7 is hinged on the lifting platform 6, and an angle adjustment push rod 8 is hinged between the cradle 7 and the lifting platform 6;

[0058] By setting the angle of the cradle 7 to be adjustable, the valve flange body 15 can be welded on the outer wall surface of the pipe body 4 and on the axial port of the pipe body 4, thereby improving the versatility and applicable scenarios of the welding device;

[0059] The guide arc groove 9 is provided on the cradle 7. The inner wall of the guide arc groove 9 is slidably connected with a slide 10. The slide 10 is provided with an arc frame 12 driven by a motor c11. The motor c11 is installed on the cradle 7. The arc frame 12 is rotatably connected with an indexing seat 14 driven by a transmission worm 13.

[0060] A driven gear connected to the transmission worm 13 is mounted on the indexing seat 14;

[0061] A toothed ring 28 is fixedly mounted on the arc frame 12, and a driving gear is fixedly mounted on the output shaft end of the motor c11, and the driving gear is transmission-connected with the toothed ring 28. The full arc of the toothed ring 28 is 190°, and the full arc of the guide arc groove 9 is 250°. The axis of the toothed ring 28 is in the same straight line as the rotation axis of the guide arc groove 9 and the indexing seat 14.

[0062] A clamping component is installed on the indexing seat 14 and clamps the valve flange body 15;

[0063] Two welding gun assemblies are mounted at both ends of the arc frame 12 and connected to the welding machine 3;

[0064] The clamping component includes a clamping screw b29 rotatably connected to the indexing seat 14 and a group of guide rods 30 fixed to the bottom surface of the indexing seat 14. The clamping screw b29 is symmetrically provided with a positive thread portion b and a negative thread portion b. The positive thread portion b and the negative thread portion are both transmission-connected with a clamping seat 31. The clamping seat 31 is slidably connected to the guide rod 30. A group of clamps 32 for clamping the valve flange body 15 are provided on the outer side of the clamping seat 31. A connecting rod 33 is hinged between each clamp 32 and the relative surfaces of the two clamping seats 31, and a pressure block 38 is installed on each clamp 32.

[0065] The welding gun assembly includes a universal rocking ball 34 embedded in the arc frame 12, a connecting tube 35 is installed at the bottom end of the universal rocking ball 34, a welding gun body 36 is clamped on the inner wall of the connecting tube 35, and the welding gun body 36 is connected to the welding machine 3 through a pipeline. A locking angle piece 37 for limiting the angle of the universal rocking ball 34 is threadedly installed on the arc frame 12.

[0066] By setting the universal rocker ball 34, the welding angle of the welding gun body 36 is precisely limited;

[0067] The clamping structure of the welding gun body 36 and the connecting pipe 35 is set to accurately define the distance between the welding port of the welding gun body 36 and the valve flange body 15;

[0068] The present invention also proposes a welding method for a valve flange-pipeline welding device, comprising the following steps:

[0069] SS01. Default: Before welding, the welding platform 1 is mounted on the pipeline body 4. After the welding platform 1 is arranged, the position of the welding platform 1 on the pipeline body 4 is adjusted according to the position of the welding port of the valve flange body 15, and finally the axis of the arc frame 12 and the axis of the welding port of the valve flange body 15 are aligned in the same straight line. After the position of the arc frame 12 is adjusted, the position of the welding platform 1 is locked by the transmission wheel 27.

[0070] SS02, fixation, after step SS01, the valve flange body 15 is fixed on the transfer seat 14 by means of a clamping component. After the valve flange body 15 is fixed, the layout height and layout angle of the arc frame 12 are adjusted so that the valve flange body 15 is aligned with the welding port and the bottom end of the valve flange body 15 is closely fitted with the welding port;

[0071] SS03, welding, after step SS02, the motor c11 drives the two welding gun bodies 36 to rotate 185° counterclockwise along the axis of the axis of the indexing seat 14, thereby completing the welding operation of the valve flange body 15 on the pipeline body 4.

[0072] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit thereof, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A valve flange-pipe welding device, comprising a welding station (1), characterized in that: Also includes: A distance adjusting member and a welding machine (3), wherein the distance adjusting member and the welding machine (3) are both mounted on a welding platform (1), and the distance adjusting member is drivingly connected to two mirror-image-arranged pipe clamping modules, and the two pipe clamping modules are fixed on a pipe body (4); The pipe clamp module comprises an outer clamp seat (16) and an inner clamp seat (17), the outer clamp seat (16) and the inner clamp seat (17) are both slidably connected to the welding platform (1), a group of pressure sensors (18) are installed between the opposing surfaces of the outer clamp seat (16) and the inner clamp seat (17), the outer clamp seat (16) is driven by a distance adjusting member, and four regularly distributed universal clamp beads (19) are embedded on the inner clamp seat (17); The distance adjusting member comprises a clamping screw a (20) which is rotatably connected between the inner surfaces of the welding platform (1) and driven by a motor (2), wherein the clamping screw a (20) is provided with a positive thread portion a and a negative thread portion a in a mirror-image manner, and the positive thread portion a and the negative thread portion a are respectively transmission-connected to the outer clamping seats (16) in the two pipe clamping modules; A locking and guiding component, used to change the layout position of the welding platform (1) on the pipeline body (4) and to lock the position of the welding platform (1); The locking and guiding component comprises a motor a (21) mounted on the welding table (1), a shaft sleeve (22) rotatably connected to the welding table (1), and a transmission seat (23) slidably connected to the welding table (1), the output shaft end of the motor a (21) and the shaft sleeve (22) are both fixedly mounted with driven bevel gears, the two driven bevel gears are meshed with each other, a rotating shaft (24) is fixedly mounted on the top surface of the transmission seat (23), the rotating shaft (24) is transmission-connected to the shaft sleeve (22), a pressure spring (25) is sleeved on the rotating shaft (24) and corresponds to the position between the shaft sleeve (22) and the transmission seat (23), and the inner wall of the transmission seat (23) is rotationally connected with a transmission wheel (27) driven by the motor b (26); A lifting screw rod (5) is mounted on the welding platform (1); the lifting screw rod (5) is drivingly connected to a lifting platform (6); a cradle (7) is hingedly connected to the lifting platform (6); an angle adjustment push rod (8) is hingedly connected between the cradle (7) and the lifting platform (6); A guide arc groove (9) is formed on the cradle (7); the inner wall of the guide arc groove (9) is slidably connected to a slide table (10); an arc frame (12) driven by a motor c (11) is mounted on the slide table (10); the motor c (11) is mounted on the cradle (7); and a transfer seat (14) driven by a transmission worm (13) is rotatably connected to the arc frame (12); A clamping member is mounted on the transfer seat (14) and clamps the valve flange body (15); The clamping component comprises a clamping screw b (29) rotatably connected to the indexing seat (14) and a group of guide rods (30) fixed to the bottom surface of the indexing seat (14); the clamping screw b (29) is symmetrically provided with a positive thread portion b and a negative thread portion b; the positive thread portion b and the negative thread portion are both transmission-connected with a clamping seat (31); the clamping seat (31) is slidably connected to the guide rod (30); a group of clamps (32) for clamping the valve flange body (15) are provided on the outer side of the clamping seat (31); a connecting rod (33) is hinged between each clamp (32) and the opposite surface of the two clamping seats (31); and a pressure block (38) is installed on each clamp (32); Two welding gun assemblies are mounted on both ends of the arc frame (12) and connected to the welding machine (3).

2. A valve flange-pipe welding device according to claim 1, characterized in that: The shaft sleeve (22) is fixedly provided with a shaft groove with two ends open and slidably connected to the rotating shaft (24); the cross-sections of the shaft groove and the rotating shaft (24) are both regular polygons; and the axial direction of the rotating shaft (24) is perpendicular to the axial direction of the pipe body (4).

3. A valve flange-pipe welding device according to claim 2, characterized in that: A toothed ring (28) is fixedly mounted on the arc frame (12), a driving gear is fixedly mounted on the output shaft end of the motor C (11), the driving gear is drivingly connected to the toothed ring (28), the full arc of the toothed ring (28) is 190°, the full arc of the guide arc groove (9) is 250°, and the axis of the toothed ring (28) is on the same straight line as the rotation axis of the guide arc groove (9) and the indexing seat (14).

4. A valve flange-pipe welding device according to claim 3, characterized in that: The welding gun assembly comprises a universal rocking ball (34) embedded in an arc frame (12); a connecting pipe (35) is installed at the bottom end of the universal rocking ball (34); a welding gun body (36) is clamped on the inner wall of the connecting pipe (35); the welding gun body (36) is connected to the welding machine (3) through a pipeline; and a locking angle piece (37) for limiting the angle of the universal rocking ball (34) is threadedly installed on the arc frame (12).

5. A valve flange-pipe welding device according to claim 4, characterized in that: A driven gear which is drivingly connected to the driving worm (13) is mounted on the indexing seat (14).

6. A welding method for a valve flange-pipe welding device as claimed in claim 5, characterized in that: The following steps are involved: SS01. It is assumed that before welding, the welding platform (1) is mounted on the pipeline body (4). After the welding platform (1) is arranged, the position of the welding platform (1) on the pipeline body (4) is adjusted according to the position of the welding port of the valve flange body (15), and finally the axis of the arc frame (12) and the axis of the welding port of the valve flange body (15) are aligned in the same straight line. After the position of the arc frame (12) is adjusted, the position of the welding platform (1) is locked by the transmission wheel (27); SS02, fixation, after step SS01, fix the valve flange body (15) on the transfer seat (14) by means of a clamping component. After the valve flange body (15) is fixed, adjust the layout height and layout angle of the arc frame (12) so that the valve flange body (15) is aligned with the welding port and the bottom end of the valve flange body (15) is tightly fitted with the welding port; SS03, welding, after step SS02, the motor c (11) drives the two welding gun bodies (36) to rotate 185 degrees counterclockwise along the axis of the axis of the indexing seat (14), thereby completing the welding operation of the valve flange body (15) on the pipe body (4).

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