Pipeline welding inner wall anti-oxidation gas blocking control device

Abstract

The invention provides a pipeline welding inner wall anti-oxidation gas blocking control device, and relates to the technical field of electric arc welding, the pipeline welding inner wall anti-oxidation gas blocking control device comprises two traction seats, a gas conveying pipe is concentrically and fixedly inserted in the traction seats, a pipe core is fixedly inserted in the gas conveying pipe, and a plurality of gas conveying channels are formed in the outer circular surface of the pipe core and the inner circular surface of the gas conveying pipe; the device comprises two traction seats, and further comprises a plurality of supporting assemblies installed at the outer ends of the traction seats, plugging assemblies installed at the ends, close to each other, of the two traction seats, and a follow-up gas conveying assembly installed between the two gas conveying pipes. The inert gas consumption is remarkably reduced while the welding quality is guaranteed, the plugging assembly and the supporting assembly are additionally arranged, the device adapts to pipelines with different diameters, the inflation space is reduced, meanwhile, the inert gas can be preheated through the special gas conveying channel in the traction base, and the temperature of a molten pool is prevented from being affected.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of arc welding, in particular to a kind of pipe welding inner wall anti-oxidation gas plugging control device. BACKGROUND

[0002] In the process of arc welding of large-diameter pipeline, in order to protect the internal welding joint from oxidation, inert gas is generally filled into the pipeline to block oxygen, so as to avoid the oxidation of the root metal of the weld and the occurrence of slag overflow phenomenon, thereby ensuring the welding quality.

[0003] At present, when the pipeline is plugged, the two ends of the pipeline are plugged by plugging members, and then inert gas is filled into the pipeline to isolate oxygen. This plugging method causes a large space between the pipeline and the two plugging members, so that more inert gas is filled, and when the gas is ventilated, the welder sets the gas flow to the maximum value suitable for the workpiece welding according to experience, or directly adjusts the gas supply to the limit value of gas input. Not only does it cause waste of inert gas, but also increases the inflation time, affecting the overall welding efficiency. SUMMARY

[0004] The purpose of the present application is to solve the problem that in the prior art, when the pipeline is plugged, the two ends of the pipeline are plugged by plugging members, and the amount of gas filled needs to be adjusted manually, which not only reduces the inflation efficiency, but also wastes the amount of inert gas used.

[0005] In order to achieve the above purpose, the present application adopts the following technical scheme: a kind of pipe welding inner wall anti-oxidation gas plugging control device, including traction seat, the traction seat is equipped with two and the concentric fixed plug-in gas pipe in the traction seat, the gas pipe is fixedly inserted with pipe core, the outer circular surface of the pipe core and the inner circular surface of the gas pipe are provided with a plurality of gas passages, and further comprising: A plurality of support assemblies are installed on the outer end of the traction seat, which can center the traction seat when welding pipes of different diameters; A plugging assembly is installed on the end of the two traction seats close to each other to form a protective gas cavity in the weld area of the pipeline to be welded; A follow-up gas assembly is installed between the two gas pipes to deliver protective gas in real time according to the weld position of the pipeline to be welded.

[0006] In at least some embodiments, the plurality of gas passages are arranged in a ring array and the gas passages are spiral, the outer end of the gas pipe is provided with a plurality of axial strip grooves and a heating tape is installed in the strip groove, a heat preservation tube is provided between the gas pipe and the inner wall of the traction seat, one end of the gas pipe is fixedly connected with a buffer gas disc, and an electromagnetic valve is installed on the gas inlet of the buffer gas disc.

[0007] In at least some embodiments, the support assembly includes a spring telescopic rod and a crawler wheel, the outer end of the traction seat is integrally formed with a plurality of convex edges in an annular array, the spring telescopic rod is installed at one end of the convex edge and a sliding block is fixedly connected to the telescopic end, a sliding groove is formed in the convex edge in the same telescopic direction as the spring telescopic rod and the sliding block is slidingly installed in the sliding groove, two support rods are rotatably connected between the crawler wheel and the convex edge, and a transmission rod is rotatably connected between the crawler wheel and the sliding block. Under the elastic force of the spring telescopic rod, the sliding block is pushed and the crawler wheel is unfolded outward to fit the inner wall of the pipeline to be welded.

[0008] In at least some embodiments, the plugging assembly includes a mounting seat and a plugging air bag, the mounting seat is fixedly installed at one end of the traction seat and the gas delivery pipe penetrates the mounting seat, a top ring rotatably connected with the umbrella frame is slidingly sleeved on the mounting seat, a plurality of guide rods movably inserted into the mounting seat are fixedly installed on the top ring, and an electric push rod for driving the top ring to slide is fixedly installed on the mounting seat to control the expansion and contraction of the umbrella frame.

[0009] In at least some embodiments, the mounting seat is installed with an umbrella frame and the umbrella frame is provided with an elastic skin, the plugging air bag is fixedly installed at the outer circular end of the umbrella frame and the plugging air bag is fixedly sewn with the skin, and a gas pressure sensor is arranged in the plugging air bag.

[0010] In at least some embodiments, the plugging air bag is in the form of a circular ring and an anti-skid rubber strip is fixedly bonded to the outer circular edge, the anti-skid rubber strip is in the form of an annular wave shape to improve the friction between the plugging air bag and the inner wall of the pipeline to be welded without affecting the sealing effect.

[0011] In at least some embodiments, the follow-up gas delivery assembly includes an air outlet pipe and a plugging block, the two ends of the air outlet pipe are rotatably communicated with the air outlet ends of the two gas delivery pipes, the air outlet pipe is designed in a four-way manner and is provided with an inclined partition in the middle, a horn cover is fixedly installed at one of the air outlets of the air outlet pipe to improve the gas diffusion range, a sleeve is fixedly installed at the other air outlet of the air outlet pipe, a telescopic pipe is movably inserted into the sleeve, a flow distribution disc is fixedly communicated with the top end of the telescopic pipe, a pre-tightening spring is sleeved between the flow distribution disc and the periphery of the sleeve, and two connecting pipes are fixedly communicated between the plugging block and the flow distribution disc. Under the elastic force of the pre-tightening spring, the plugging block tightly abuts against the weld.

[0012] In at least some embodiments, the plugging block is in the form of an arc and is internally provided with two opposite convection air channels and an open air groove, the two convection air channels are fixedly communicated with the two connecting pipes, respectively, a plurality of air holes are formed in the walls adjacent to the air bag of the two convection air channels to prevent the airflow from directly blowing the molten pool, and a plurality of ball bearings are installed at the arc end of the plugging block.

[0013] In at least some embodiments, one end of the air outlet pipe is fixedly sleeved with a driven gear, a motor for driving the driven gear to rotate is fixedly installed on the blocking assembly, and a heat sensor is installed in the air groove of the blocking block to control the motor to drive the blocking block to follow the gas supply.

[0014] Compared with the prior art, the advantages and positive effects of the present application are that: 1、In the present application, through the double gas protection design of "overall atmosphere protection plus local follow-up protection of the welding seam", the welding quality is ensured while the inert gas consumption is significantly reduced. On the one hand, a large range of protective atmosphere is formed in the welding area through the diffusion port (horn cover) of the air outlet pipe, and on the other hand, the back of the welding seam is locally and highly concentratedly protected through the blocking block which can move with the welding position. This double mechanism can not only avoid the gas waste of the traditional overall gas filling mode, but also ensure the stability of the gas concentration in the molten pool area, thereby improving the protection effect and economy.

[0015] 2、In the present application, two blocking air bags which can be independently controlled and are arranged close to the welding seam are adopted, and a compact "protective gas cavity" is directly formed on both sides of the welding seam. This design minimizes the closed space to be filled, thereby greatly reducing the inert gas filling amount and filling time, improving the welding efficiency, and reducing the gas cost. In addition, through the linkage design of the spring telescopic rod and the track wheel in the supporting assembly, the traction seat can self-adapt to the inner wall of the pipeline with different diameters to realize automatic centering and stable movement, so that the device can be flexibly applied to pipelines with various specifications, and the overall process adaptability is improved.

[0016] 3、In the present application, the heat tracing band and the heat preservation pipe are arranged in the gas conveying pipe, so that the protective gas can be preheated in a low-temperature environment to avoid the influence of cold gas on the molten pool temperature, thereby ensuring the thermal stability during the welding process. In addition, the internal part of the blocking block is designed with a convection air duct and a porous air outlet, so that the gas flows out uniformly and slowly from the side to avoid the oxidation of the welding seam or the temperature fluctuation caused by direct blowing of the molten pool. This "preheating and buffering" gas flow control mode further improves the reliability and consistency of the welding seam formation. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 A whole three-dimensional schematic view of a pipeline welding inner wall anti-oxidation gas blocking control device is provided for the present application. Figure 2 A structure schematic view of a traction seat in a pipeline welding inner wall anti-oxidation gas blocking control device is provided for the present application. Figure 3 An internal structure schematic view of a traction seat in a pipeline welding inner wall anti-oxidation gas blocking control device is provided for the present application. Figure 4 A structure schematic view of a gas conveying pipe in a pipeline welding inner wall anti-oxidation gas blocking control device is provided for the present application. Figure 5 A structure diagram of a plugging assembly in a pipeline welding inner wall anti-oxidation gas plugging control device is provided for the present application. Figure 6 A structure diagram of a plugging air bag in a pipeline welding inner wall anti-oxidation gas plugging control device is provided for the present application. Figure 7 A structure diagram of a tunnel gas conveying assembly in a pipeline welding inner wall anti-oxidation gas plugging control device is provided for the present application. Figure 8 A structure diagram of a plugging block in a pipeline welding inner wall anti-oxidation gas plugging control device is provided for the present application.

[0018] Legend: 1, traction seat; 101, convex rib; 2, support assembly; 201, spring telescopic rod; 202, sliding block; 203, track wheel; 204, support rod; 205, transmission rod; 3, gas conveying pipe; 301, pipe core; 302, gas conveying channel; 303, heat tracing band; 304, heat preservation pipe; 305, buffer gas disc; 4, plugging assembly; 401, mounting seat; 402, plugging air bag; 403, umbrella frame; 404, top ring; 405, guide rod; 406, electric push rod; 407, anti-skid rubber strip; 5, follow-up gas conveying assembly; 501, gas outlet pipe; 502, spacer; 503, horn cover; 504, sleeve; 505, telescopic pipe; 506, shunt disc; 507, pre-tightening spring; 508, plugging block; 509, connecting pipe; 510, driven gear. DETAILED DESCRIPTION

[0019] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application will be further described below in conjunction with the drawings and examples. It should be noted that the examples of the present application and the features in the examples can be combined with each other without conflict.

[0020] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, however, the present application can also be implemented in other ways different from those described herein, therefore, the present application is not limited to the specific examples disclosed in the following description.

[0021] Embodiment, according to Figures 1-8 The pipeline welding inner wall anti-oxidation gas plugging control device provided by the embodiment of the present application comprises a traction seat 1, such as Figure 1As shown, the traction seat 1 is provided with two and the traction seat 1 is concentrically fixed with the gas conveying pipe 3, the gas conveying pipe 3 is fixed with the pipe core 301, the outer circular surface of the pipe core 301 and the inner circular surface of the gas conveying pipe 3 are provided with a plurality of gas conveying channels 302, further comprising a plurality of support assemblies 2 installed at the outer end of the traction seat 1, which can center the traction seat 1 when welding different diameter pipes, a sealing assembly 4 installed at the end of the two traction seats 1 close to each other to form a protective gas cavity in the weld area of the pipe to be welded, and a follow-up gas conveying assembly 5 installed between the two gas conveying pipes 3 to real-time follow-up conveying protective gas for the weld position of the pipe to be welded.

[0022] As shown in Figure 2 The support assembly 2 includes a spring telescopic rod 201 and a track wheel 203, the outer end of the traction seat 1 is integrally formed with a plurality of convex edges 101 in a ring array, the spring telescopic rod 201 is installed at one end of the convex edge 101 and the telescopic end is fixedly connected with a sliding block 202, the convex edge 101 is provided with a sliding groove in the same telescopic direction as the spring telescopic rod 201, and the sliding block 202 is slidingly installed in the sliding groove, two support rods 204 are rotatably connected between the track wheel 203 and the convex edge 101, and a transmission rod 205 is rotatably connected between the track wheel 203 and the sliding block 202, under the elastic force of the spring telescopic rod 201, the sliding block 202 is pushed and the track wheel 203 is unfolded outward to fit the inner wall of the pipe to be welded, wherein the sliding block 202 is continuously pushed along the sliding groove by the pre-tightening elastic force of the spring telescopic rod 201, the track wheel 203 is pushed outward by the sliding block 202 through the transmission rod 205, until the track surface of the track wheel 203 contacts and is pressed against the inner wall of the pipe, and at the same time the support rod 204 provides auxiliary support for the track wheel 203, so that the track wheel 203 remains stable when rolling in the pipe, this structure can adapt to pipes of different diameters within a certain range, ensure that the traction seat 1 is centered in the pipe, and can move axially along the pipe during welding.

[0023] As shown in Figure 3 and Figure 4As shown, the plurality of gas conveying channels 302 are arranged in a ring array and the gas conveying channels 302 are spiral, the outer end of the gas conveying pipe 3 is provided with a plurality of axial strip-shaped grooves and the strip-shaped grooves are provided with heating tapes 303, the gas conveying pipe 3 and the inner wall of the traction seat 1 are provided with heat preservation pipes 304, one end of the gas conveying pipe 3 is fixedly connected with a buffer gas disc 305, and the gas inlet of the buffer gas disc 305 is provided with an electromagnetic valve, wherein the spiral gas conveying channel 302 can prolong the gas flow path, so that the gas is buffered and homogenized during conveying, and the gas flow impact is avoided; the heating tape 303 can be started when welding in a low temperature environment, so as to heat the gas conveying pipe 3 and prevent the inert gas from affecting the temperature of the molten pool due to the low temperature; the heat preservation pipe 304 is wrapped outside the gas conveying pipe 3, further reducing heat loss; the buffer gas disc 305 is provided with a cavity inside, which can temporarily store and stabilize the pressure of the gas, and the electromagnetic valve controls the on-off and flow of the gas (the electromagnetic valve is electrically connected with the gas pressure sensor), so as to realize adjustable supply of the gas.

[0024] As shown in 5 and Figure 6 As shown, the plugging assembly 4 comprises a mounting seat 401 and a plugging air bag 402, the mounting seat 401 is fixedly installed at one end of the traction seat 1 and the gas conveying pipe 3 penetrates through the mounting seat 401, a top ring 404 rotationally connected with a rib frame 403 is slidably sleeved on the mounting seat 401, a plurality of guide rods 405 movably inserted with the mounting seat 401 are fixedly installed on the top ring 404, an electric push rod 406 for driving the top ring 404 to slide is fixedly installed on the mounting seat 401, so as to control the expansion and contraction of the rib frame 403, wherein the electric push rod 406 drives the top ring 404 to move axially along the mounting seat 401, the top ring 404 drives the rib frame 403 to rotate around the hinge point between the rib frame 403 and the mounting seat 401 through the connecting rod, so as to realize the unfolding and folding of the rib frame 403, and the guide rods 405 ensure the smooth movement of the top ring 404 and improve the control accuracy; The rib frame 403 is installed on the mounting seat 401 and the rib frame 403 is provided with an elastic skin, the plugging air bag 402 is fixedly installed at the outer circular end of the rib frame 403 and the plugging air bag 402 is fixedly sewn with the skin, and a gas pressure sensor is arranged in the plugging air bag 402, wherein the rib frame 403 drives the skin and the plugging air bag 402 to open after being unfolded, the plugging air bag 402 can be inflated with a certain pressure to make it expand and tightly contact with the inner wall of the pipeline, so as to form a ring-shaped seal, the gas pressure sensor monitors the internal pressure of the plugging air bag 402 in real time and controls the opening and closing degree of the electromagnetic valve, so as to ensure the reliability of the sealing under the premise of not wasting the amount of gas; The blocking air bag 402 is in the shape of a ring, and an anti-skid rubber strip 407 is fixedly bonded to the outer circular edge of the blocking air bag 402. The anti-skid rubber strip 407 is in the shape of a ring wave, so as to improve the friction between the blocking air bag 402 and the inner wall of the pipeline to be welded without affecting the sealing effect. The wave-shaped design of the anti-skid rubber strip 407 increases the contact area and the friction coefficient with the inner wall of the pipeline, so that the device can be effectively prevented from slipping in the pipeline due to the gas pressure or the moving inertia, and the elastic deformation capability of the anti-skid rubber strip 407 does not affect the sealing fit of the air bag.

[0025] As shown in Figure 7 and Figure 8 , the follow-up gas delivery assembly 5 includes a gas outlet pipe 501 and a blocking block 508. The two ends of the gas outlet pipe 501 are in rotational communication with the gas outlet ends of the two gas delivery pipes 3, respectively. The gas outlet pipe 501 adopts a four-way design and is provided with an inclined partition plate 502 in the middle. A horn cover 503 is fixedly installed at one of the gas outlets of the gas outlet pipe 501 to improve the gas diffusion range. A sleeve 504 is fixedly installed at the other gas outlet of the gas outlet pipe 501. A telescopic pipe 505 is movably inserted into the sleeve 504. A flow distribution disc 506 is fixedly communicated with the top end of the telescopic pipe 505. A pre-tightening spring 507 is sleeved between the flow distribution disc 506 and the outer periphery of the sleeve 504. Two connecting pipes 509 are fixedly communicated between the flow distribution disc 506 and the blocking block 508. The blocking block 508 is tightly attached to the weld under the elastic force of the pre-tightening spring 507. The gas outlet pipe 501 converges the protective gas from the two gas delivery pipes 3. The partition plate 502 separates and guides the gas flow to different outlets. The horn cover 503 sprays a part of the gas to diffuse, which is used to protect the welding area in advance. The sleeve 504 and the telescopic pipe 505 constitute a telescopic gas path. The pre-tightening spring 507 pushes the flow distribution disc 506 downward, so that the blocking block 508 connected with the flow distribution disc 506 is always pressed against the weld position with a certain pressure, and follows the weld shape. The flow distribution disc 506 divides the gas into two paths to be delivered to the blocking block 508 through the connecting pipes 509. The blocking block 508 is in the shape of an arc and is internally provided with two opposite convection air channels and an open air groove. The two convection air channels are fixedly communicated with the two connecting pipes 509, respectively. A plurality of air holes are formed in the wall adjacent to the air bag of the two convection air channels, so that the gas flow does not blow directly to the molten pool. A plurality of balls are installed at the arc end of the blocking block 508. The gas entering from the connecting pipes 509 flows in the convection air channels and is evenly and gently discharged to the air groove area through the air holes, so as to avoid the welding defects caused by the direct blowing of high-speed gas flow to the molten pool. The open air groove is opposite to the back of the weld, forming a local high-concentration gas protection area (under the condition that the amount of inert gas is not wasted, the double protection mechanism of the overall atmosphere protection and the specific key protection is realized). The balls reduce the sliding friction between the blocking block 508 and the weld area, so that the blocking block 508 can smoothly move along the weld. One end of the air outlet pipe 501 is fixedly sleeved with a driven gear 510, the blocking assembly 4 is fixedly installed with a motor for driving the driven gear 510 to rotate, and a heat sensor is installed in the air groove of the blocking block 508 to control the motor to drive the blocking block 508 to follow the air supply, wherein the heat sensor detects the heat distribution of the welding seam position (corresponding to the movement of the welding arc) in real time, transmits the signal to the control system, and the control system instructs the motor to drive the driven gear 510 to rotate, thereby driving the air outlet pipe 501 and the blocking block 508 below to rotate around the air outlet pipe 3 axis, so that the air groove of the blocking block 508 is always aligned with the back of the molten pool being welded, and the precise and follow-up supply of the protective gas is realized.

[0026] The above is only a preferred embodiment of the present application, and is not intended to limit the present application in other forms. Any person skilled in the art can modify or change the above disclosed technical content to equivalent embodiments applied to other fields, but any simple modification, equivalent change and modification made to the above embodiments without departing from the technical solution content of the present application, according to the technical essence of the present application, still belongs to the protection scope of the technical solution of the present application.

Claims

1. A pipeline welding inner wall anti-oxidation gas plugging control device, comprising a traction seat (1), characterized in that: The traction seat (1) is provided with two and the traction seat (1) is fixedly inserted with the gas conveying pipe (3) concentrically, the gas conveying pipe (3) is fixedly inserted with the pipe core (301), the outer circular surface of the pipe core (301) and the inner circular surface of the gas conveying pipe (3) are provided with a plurality of gas conveying channels (302), and further comprising: A plurality of support assemblies (2) are mounted on the outer end of the traction seat (1), which can center the traction seat (1) when welding different diameter pipes; A sealing assembly (4) is mounted on the end of the two traction seats (1) close to each other to form a protective gas cavity in the weld area of the pipe to be welded; A follow-up gas conveying assembly (5) is installed between the two gas conveying pipes (3) to real-time follow-up the welding position of the weld of the pipe to be welded to convey protective gas.

2. A device for preventing the oxidation of the inner wall of a pipe during welding, according to claim 1, characterized in that: A plurality of the gas conveying channels (302) are arranged in a ring array and the gas conveying channel (302) is in a spiral type, the outer end of the gas conveying pipe (3) is provided with a plurality of axial strip grooves and a heating tape (303) is installed in the strip groove, the gas conveying pipe (3) and the inner wall of the traction seat (1) are provided with a heat preservation pipe (304), one end of the gas conveying pipe (3) is fixedly connected with a buffer gas disc (305), and the gas inlet of the buffer gas disc (305) is provided with an electromagnetic valve.

3. The apparatus according to claim 1, wherein: The support assembly (2) comprises a spring telescopic rod (201) and a crawler wheel (203), the outer end of the traction seat (1) is integrally formed with a plurality of convex edges (101) in a ring array, the spring telescopic rod (201) is mounted on one end of the convex edge (101) and the telescopic end is fixedly connected with a sliding block (202), the convex edge (101) is provided with a sliding groove in the same telescopic direction as the spring telescopic rod (201) and the sliding block (202) is slidingly installed in the sliding groove, two support rods (204) are rotatably connected between the crawler wheel (203) and the convex edge (101), and a transmission rod (205) is rotatably connected between the crawler wheel (203) and the sliding block (202), under the elastic force of the spring telescopic rod (201), the sliding block (202) is pushed and the crawler wheel (203) is driven to expand outward to fit the inner wall of the pipe to be welded.

4. The apparatus for preventing the oxidation of the inner wall of a pipe during welding according to claim 1, wherein: The sealing assembly (4) comprises a mounting seat (401) and a sealing air bag (402), the mounting seat (401) is fixedly installed on one end of the traction seat (1) and the gas conveying pipe (3) penetrates the mounting seat (401), the mounting seat (401) is slidingly sleeved with a top ring (404) rotatably connected with an umbrella frame (403), a plurality of guide rods (405) are fixedly installed on the mounting seat (401) and movably inserted into the mounting seat (401), an electric push rod (406) is fixedly installed on the mounting seat (401) for driving the top ring (404) to slide, so as to control the umbrella frame (403) to be expanded and contracted.

5. A device for preventing the ingress of oxidizing gas into a weld in a pipe according to claim 4, wherein: The mounting seat (401) is provided with the umbrella frame (403) and the umbrella frame (403) is provided with an elastic skin, the sealing air bag (402) is fixedly installed on the outer circular end of the umbrella frame (403) and the sealing air bag (402) is fixedly sewn with the skin, and the sealing air bag (402) is provided with a gas pressure sensor.

6. A device for controlling the flow of an inert gas to the inside of a pipe to be welded according to claim 5, characterized in that: The blocking air bag (402) is in the shape of a ring, and an anti-skid rubber strip (407) is fixedly bonded to the outer circular edge of the blocking air bag (402), and the anti-skid rubber strip (407) is in the shape of a ring-shaped wave, so as to improve the friction between the blocking air bag (402) and the inner wall of the pipeline to be welded without affecting the sealing effect.

7. A device for preventing the oxidation of the inner wall of a pipe during welding, according to claim 1, characterized in that: The follow-up gas supply assembly (5) comprises a gas outlet pipe (501) and a blocking block (508), two ends of the gas outlet pipe (501) are in rotational communication with the gas outlet ends of two gas supply pipes (3) respectively, the gas outlet pipe (501) is designed in a four-way manner and is provided with an inclined partition (502) in the middle part, a horn cover (503) is fixedly installed at one of the gas outlets of the gas outlet pipe (501) so as to improve the gas diffusion range, a sleeve pipe (504) is fixedly installed at the other gas outlet of the gas outlet pipe (501), a telescopic pipe (505) is movably installed in the sleeve pipe (504), a flow distribution disc (506) is fixedly communicated with the top end of the telescopic pipe (505), a pre-tightening spring (507) is sleeved between the flow distribution disc (506) and the periphery of the sleeve pipe (504), and two connecting pipes (509) are fixedly communicated between the blocking block (508) and the flow distribution disc (506), so that the blocking block (508) is tightly attached to the weld under the elastic force of the pre-tightening spring (507).

8. A device for controlling the flow of an inert gas to the inside of a pipe to be welded according to claim 7, characterized in that: The blocking block (508) is in the shape of an arc and is internally provided with two opposite convection air channels and an open air groove, the two convection air channels are fixedly communicated with the two connecting pipes (509) respectively, a plurality of air holes are formed in the wall adjacent to the air bag of the two convection air channels, so that the airflow cannot directly blow on the molten pool, and a plurality of balls are installed at the arc end of the blocking block (508).

9. A device for controlling the flow of an inert gas to the inside of a pipe to be welded according to claim 8, characterized in that: One end of the gas outlet pipe (501) is fixedly sleeved with a driven gear (510), the blocking assembly (4) is fixedly installed with a motor for driving the rotation of the driven gear (510), and a heat sensor is installed in the air groove of the blocking block (508) to control the motor to drive the follow-up gas supply of the blocking block (508).

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