KR102332633B1 - Anti-leakage device of purge gas for welding - Google Patents

Abstract

The present invention relates to a method for preventing leakage of purge gas of a welding device for connecting one end of a pipe with one end of another pipe by butt welding. A device for preventing leakage of purge gas for welding according to the present invention is a device for preventing leakage of purge gas for welding, which is supplied in a process of root-pass welding of a butt-joint part of pipes using a welding torch of the welding device including a pipe rotating device. The device for preventing leakage of purge gas for welding comprises: a belt having a width and fastened in a circular shape along the joint part; an opening formed in the belt to allow the torch to access the joint part; an elastic part for contracting the belt fastened in the circular shape; and a holding part extending from the belt and fixing the belt to a surrounding fixed object. The elastic part maintains close contact between the pipe and the belt along the joint part, and the holding part maintains the position of the opening by applying tension in a direction opposed to the rotation direction of the pipe. The device for preventing leakage of purge gas according to the present invention eliminates the need to dispatch an operator to remove purge paper in a process of pipe butt-joint part welding (super-layer MIG welding) and is capable of automatically closing a welding part gap according to the movement path of the torch.

Description

Anti-leakage device of purge gas for welding

The present invention relates to a method of preventing leakage of purge gas of a welding apparatus for connecting one end of a pipe and another end of a pipe by welding.

When the molten metal is exposed to the air during TIG or MIG super-layer welding in the butt joint of a pipe such as a stainless pipe or a titanium pipe, the molten metal is oxidized (refer to FIG. 1) and the original properties of the metal are lost. In this case, in order to prevent oxidation of molten metal, the spaces inside the pipe butt joint are sealed with a sponge or purge paper, etc., as shown in the purge operation conceptual diagram shown in FIG. 2, and the outside of the joint is sealed with a purge tape. Do not attach the purge tape so that about 50mm is a space where the inside air can be released. By supplying an inert gas (argon, nitrogen) into the sealing space of the butt joint and expelling the air (oxygen) of the sealing space to the outside, the oxygen concentration in the inner space of the butt joint is adjusted to be below the working standard value (eg 100ppm).

Check that the oxygen concentration in the space inside the butt joint of the pipe is less than or equal to the working standard value (example: 100 ppm), start TIG or MIG super-layer welding at the position where the purge tape is not attached on the outside of the butt joint, and proceed with welding. If the tape in the front part interferes with the welding process, stop TIG super layer welding, peel off about 50mm of the tape attached to the front part, and then complete the pipe butt joint welding by performing the connecting super layer welding. By performing pipe butt joint TIG or MIG super-layer welding in this way, it is possible to produce a healthy, non-oxidized backside bead that forms inside the pipe.

As shown in Figure 3, in manual TIG or semi-automatic MIG welding, the welder stops welding during welding, removes a part of the purge tape attached to the outside of the butt joint, and performs super-layer welding by connecting welding, but automatic TIG Alternatively, in MIG pipe super-layer welding, it is necessary to continuously remove the purge tape attached to the outside of the pipe butt joint at a certain distance (about 50mm) from the arc generation point in accordance with the welding speed. There is a problem in that the labor cost increases by separately disposing this work.

The apparatus for preventing leakage of purge gas for welding of the present invention is a device for preventing leakage for welding supplied in the process of root path welding of a pipe butt joint using a welding torch of a welding apparatus including a pipe rotating device, a belt that has a circular shape and is fastened along the joint; an opening formed in the belt to allow the torch to access the joint for root pass welding; an elastic part for contracting the belt fastened in a circle; and a holding part extending from the belt to fix the belt to a fixed object above, below, or around the pipe; and maintaining close contact with the belt, and the holding part maintains the position of the opening by applying tension in the opposite direction to the rotational direction of the pipe.

In the present invention, the opening may be a space formed between both ends of the cut surface of the belt or the elastic part connecting both ends by one or more elastic bodies.

In the present invention, the opening may be formed by cutting a portion of the belt, and the elastic portion may be formed by connecting both ends or both ends of the cut surface of the belt with one or more elastic members.

Conventionally, there is a problem in that the welding total labor cost increases because it is necessary to separately arrange a worker to remove the purge paper during pipe butt joint welding (super-layer TIG welding or MIG welding). By the purge gas leakage prevention device of the present invention, it is possible to automatically close the welding gap according to the movement path of the torch without disposing such a purge paper removal worker.

1 is a photograph of the appearance of oxidation of the back side bead of a stainless welded part;
2 is a conceptual diagram of a purge operation
3 is a purge using manual TIG welding and tape
Figure 4 is a purge device for the conventional automatic MIG super-layer welding
5 is an automatic MIG super-layer welding part and the appearance of the back bead
6 is a photograph of the back side of the automatic MIG super-layer welding and purge gas leakage prevention device
7 is a front view of automatic GMAW welding and purge device
8 is a conceptual diagram of a purge gas leakage prevention device for automatic MIG super-layer welding (front)
9 is a schematic diagram of a purge gas leakage prevention device for automatic MIG and super-layer welding (side)
10 is a belt connection device;
11 is a belt length adjustment device
12 is a binner image
13 is a belt (eg, made of fiberglass)
14 is a case of semi-automatic MIG welding using a pipe rotating device
15 is an example of a belt connection device and a welding space

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, these descriptions are merely exemplary or functional descriptions of the present invention, and since the embodiments may have various modifications and take various forms, the scope of the present invention should not be construed as being limited by these descriptions and embodiments. Can not be done. In addition, it should be understood that the scope of the present invention is not limited by this interpretation, since the object or effect presented in the present invention does not mean that a specific embodiment should include all of them or only such effects. That is, the scope of the present invention extends to equivalents that can realize the technical idea described in the claims.

In order to perform super-layer welding of stainless pipe butt joint by automatic TIG welding or automatic MIG welding, purging is performed with inert gas (argon, nitrogen, etc.) inside the pipe to prevent oxidation of the back bead during super-thickness welding. In order to prevent the purge gas from leaking between the gaps, conventionally, both ends of the pipe are sealed using a sponge membrane as shown in FIG. 4, and the weld gap is sealed by attaching a purge tape to the outer surface of the pipe. In the 50mm section, no purge tape is attached so that the gas inside the pipe can be discharged.

When the sealing work of the pipe weld is completed, the inert gas is supplied to the inside of the sealed pipe weld through the inert gas hose, and when the internal oxygen concentration is below the work instruction value, the super-layer welding work is started. When the automatic super-layer welding starts, the super-layer welding operation is continuously performed while the pipe is rotated by the rotator ( 1404 in FIG. 14 ), and the operator who removes the pre-arranged purge paper removes the purge paper at a point about 50 mm in front of the arc generation point. will be removed 5 shows the appearance of a back bead welded to a stainless pipe butt joint by automatic MIG welding.

1 is a photograph showing the appearance of oxidation of the bead on the back side of a stainless welded part, in which the welding part numbers 1, 2, and 3 are passed, and 4 to 10 are rejected due to excessive oxidation. In order to prevent this situation, a purge operation as shown in FIG. 2 is performed, and in the case of manual TIG welding, an inert gas hose 31 is inserted into the pipe 34 to be welded as shown in FIG. 3 in the prior art, and the purge paper 32 and Purge was performed using a purge tape (33). 4 is a purge device for automatic MIG super-layer welding according to the related art. A purge gas is filled in a pipe using a stopper (eg, a sponge) 42 and a purge tape, and a part of the butt joint gap 43 is opened and welded. The torch 41 shows a situation in which welding is performed in a purge gas atmosphere. 5 shows the super-layer welded part 51 and the back bead exterior 52 formed by such automatic MIG welding.

6 and 7 show the purge gas leakage prevention device of the present invention from various angles. 6 is a photograph of the back side of the device of the present invention for preventing purge gas leakage during automatic MIG super-layer welding, and while surrounding the butt joint of the pipe, the weld is opened and the belt connected to the device for maintaining the tension for close contact with the pipe (example : Glass fiber) 66, a belt support device 61 that prevents the belt from rotating in the same direction along the rotational direction of the pipe, and a wire rope connecting the belt support device and the belt (eg, stainless steel 3.0 ø) ( 64), a wire length adjusting device 63 for maintaining an appropriate tension so that the belt does not rotate along the rotational direction of the pipe, and the binner 65 connecting the wire and the belt and moving the belt left and right according to the left and right movement of the welding position It shows the state in which the belt left and right movement device 62 that can be made is coupled.

The belt, which is a component of the present invention, is used during welding and therefore must be non-combustible at high temperatures. In addition, in order to seal the purge gas leaking in the circumferential direction of the pipe from the gap of the butt welded part of the pipe, tension (tension) is applied to the belt to surround the pipe joint from the outside, so flexibility is required. As an example of such a material, a glass fiber belt or a steel band may be used, and various materials other than the illustrated material may be used. In order to improve the sealing efficiency against the purge gas leaking from the gap of the welding part by the belt made of this material, a coil spring was arranged in the belt connection part to give tension (tension) to the belt. The belt of the present invention, which performs this action, functions as a sealing device for the rotating pipe during welding.

The welding technique applied to the present invention includes TIG, MIG, and plasma welding, and can be applied to any welding that requires purging of inert gas inside the pipe. In addition, the welding equipment to which the present invention is applied includes all welding equipment that performs super-layer welding work while rotating the pipe to be welded by using a pipe rotating equipment such as a turning roller or a positioner in addition to the automatic welding equipment mentioned in the embodiment of the present invention. do. Such welding equipment includes manual TIG welding equipment or semi-automatic MIG welding equipment.

7 is a front image and an enlarged image of a purge gas leakage prevention device applied for automatic MIG welding. Two coil springs 72 are connected to the spring hooks 74 installed at both ends of the cut-off part of the belt, and tension (tension) is applied to the belt by pulling the belt. A welding torch 71 is disposed at the pipe butt joint exposed in the empty space formed between the two coil springs to perform super-layer welding. At this time, the gas inside the pipe is discharged into the space formed by the spring while preventing the overall leakage of the purge gas. The belt length adjusting device 73 functions to adjust the belt length according to the outer diameter of the pipe, and allows one long belt to be used for welding pipes of various outer diameters. In addition, by adjusting the length of the belt in the form of reducing or increasing the length of the coil spring, the tension of the belt for maintaining close contact between the outer surface of the pipe weld and the belt is adjusted.

The device of the present invention will be described with reference to FIGS. 8 and 9 showing the concept of a purge gas leakage prevention device for automatic MIG super-layer welding. 8 and 9 are schematic views showing the front and side of the purge gas leakage prevention device for automatic MIG super-layer welding. To fill the inside of the pipe butt joint with an inert gas, one end of the pipe is sealed with a sponge stopper, and the other end is closed with a sponge stopper assembled with an inert gas hose. The butt joint gap is wrapped using a belt made of glass fiber (a flexible, high-temperature, non-combustible material of non-metallic or metallic material) that can withstand the high temperature of the weld, and about 50 mm near the arcing point where the welding torch is placed is left open. and attach spring hooks to each end of the belt and connect them with coil springs. The length of the belt can be adjusted at both ends of the belt, and is adjusted from both sides using the belt length adjusting device 84 shown in FIGS. 8 and 9 . When the pipe super-layer welding starts, the pipe rotates in the direction of the arrow 94. At this time, a belt loop 92 is attached to the extension part 93 of the belt to hold the belt from rotating together. A connecting binner 91 is assembled to the belt loop, a wire rope is connected to the other end of the binner (see FIG. 12 ), and the other end of the wire rope is connected to a wire rope length adjusting device 81 . The wire rope length adjustment device 81 is attached to the belt left and right movement device 83, and consists of a hole through which the wire rope passes and a thread (tab) and a butterfly bolt that can fix the wire rope passing through the hole. . The belt moving device 83 is assembled to the belt support device 61 and used to position the wire rope and the belt directly above the butt joint gap in the left and right longitudinal direction 85 of the welded pipe. The belt position fixing device 81 may be fixedly installed on the welding head body in which the welding torch is installed, but is not limited to this position and may be installed in the form shown in FIG. 14 . This device is a device that supports the belt enclosing the outside of the welded part so that it does not rotate as one body with the pipe when the pipe to be welded rotates during super-layer welding.

10 shows a belt connection device. The belt connecting device vertically sets the belt fixing lever of the belt length adjusting device 73 (7311, open), inserts the end of the belt under it, passes it, wraps the spring hook 74 connected to the coil spring, and then returns the belt After double passing under the belt fixing lever 731 of the length adjusting device, pull the belt end to adjust the belt length, and then press the belt fixing lever in the horizontal direction (7312, closed) so that the fixing lever teeth 1102 hold the belt in the case. It is used by pressing it on the upper surface and fixing it so that it does not move. As a component of the belt length adjusting device shown in FIG. 11 , the length adjusting device case 1101 further includes fixed lever teeth 1102 for holding the belt and a fixed lever pin 1103 that is a rotation shaft of the belt fixing lever. After the primary length adjustment by the belt length adjustment device of FIG. 10 is made, a turnbuckle (a screw-type part with rings on both sides and rotating to adjust the length) is connected to the coil spring for finer length adjustment to increase and decrease tension can be adjusted. Since the pipe is standardized on the basis of the outer diameter, the outer surface of the belt to be wound on the pipe is marked with the outer diameter of the pipe in the longitudinal direction, and when the belt is installed on the outer surface of the pipe, it can be fixed to the belt length adjusting device according to the marking scale.

The biner illustrated in FIG. 12 is connected to a ring 92 that extends to the belt (eg, fiberglass material) illustrated in FIG. 13 . A wire rope 64 is fastened to the binner so that the belt does not follow the rotation direction of the pipe. 9 shows a state in which the wire rope 64 is extended upward and fixed. By adjusting the length of the wire rope (eg stainless steel, 3.0 ø) by the length adjusting device, it is possible to cope with the change in the welding arc generation position. In other words, if the wire rope length is shortened, the belt opening (the welding arc generation position; the coil spring installation position) moves clockwise (3 o'clock). will move to In actual work, the arcing point is first determined, and the position of the belt opening is aligned with the arcing point.

On the other hand, the example shown in FIG. 14 is a semi-automatic MIG welding case so that the belt does not rotate in the direction 1405 in which the pipe is rotated by the rotator 1404 including the pressure roller 1402 and the pipe rotation driving roller 1403 A wire retaining ring 1406 is shown extending downward of the device and fixed to the device. The device that breaks the belt can be fixed without limitation in the fixing direction (upper, lower, front, rear) and position so that tension is applied in the opposite direction to the pipe rotation direction to maintain the belt.

15 is an embodiment showing the belt connection device and the welding space, and the welding space 1505 necessary for the welding torch to access the pipe butt joint is formed by cutting off a part of the belt in a state where the belt is not cut. are giving In addition, as a structure for forming an elastic part for maintaining close contact with the outer circumferential surface of the pipe by adjusting the length of the belt, a part of the belt is sewn in a circle (eg) to make a cylindrical ring 1504, and a mechanical element to which the elastic body is connected (eg, for example) : The spring hook 74) can be installed in the cylindrical ring. On the other hand, when a part of the cut portion overlaps with the lower end of the belt, the purge gas flows out through the welding space 1505 inside the belt to create a welding atmosphere.

Hereinafter, a method of performing super-layer welding of a stainless pipe butt joint using an automatic MIG welding device and a purge gas leakage prevention device will be described. For pipe butt welding, the pipe to be welded is placed on the automatic MIG welding device and rotator, and fixed by pressing with a pressure roller. Place the MIG welding torch over the weld. A belt moving device, a wire rope length adjusting device, a wire rope, a connecting binner, a glass fiber belt including a belt loop, and a belt length adjusting device are assembled at both ends of the glass fiber belt, respectively, assembled in the belt support device installed in the welding head A spring hook is installed at both ends of the belt, and the hooks on both sides are connected by two coil springs, so that the belt is in close contact with the upper outer surface of the weld gap to maintain airtightness.

The belt length is primarily adjusted by the belt length adjusting device on both sides so that the belt is not placed in the welding length direction of about 50 mm (example) near the arc generation point where the welding torch is placed and the belt is in close contact with the upper surface of the weld gap with appropriate spring tension. and secondarily adjust the wire length in the wire rope length adjusting device to adjust the position of the belt opening to the arcing point.

Inert gas is supplied to the inside of the welding pipe through the inert gas hose assembled on the sponge stopper so that the internal oxygen concentration is below the working standard value.

After setting the super layer MIG welding conditions, start super layer welding.

At the same time as the arc is generated, the pipe starts to rotate at a circumferential speed corresponding to the welding speed in the direction of the arrow shown in FIG. Even during welding, the inert gas is continuously supplied in a certain amount, and the supplied amount is released between the gaps in which the belt near the arcing point is opened.

When the pipe circumferential butt joint super-layer welding construction is completed, stop the gas supply by locking the inert gas supply valve, remove the coil spring from the spring hook, and remove the belt from the outer surface of the pipe. If the belt does not interfere with pipe rotation while suspended from the belt support device, it may remain suspended until the next superlayer welding. Wait until the temperature of the super-layer weld inside the pipe is below about 200°C, and then remove the sponge stoppers assembled on both sides of the pipe and inspect the back bead appearance. Since the thickness of the first layer is formed by about 5mm by MIG welding of the first layer, it is unnecessary to purge the inert gas inside the pipe during pass welding after the first layer. Set the welding conditions for the next layer and repeat the welding of the remaining layers.

The meaning of the terms used to describe the present invention should be understood as follows. It should be understood that when an element is referred to as being “connected to” another element, it may be directly connected to the other element, but another element may exist in between. The singular expression is to be understood as including the plural expression unless the context clearly dictates otherwise, and terms such as "comprises" or "have" refer to the described feature, number, step, action, component, part or these It is intended to indicate that a combination exists, and it should be understood that it does not preclude the possibility of the existence or addition of one or more other features or numbers, steps, operations, components, parts, or combinations thereof. All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Terms defined in the dictionary should be interpreted as being consistent with the meaning of the context of the related art, and cannot be interpreted as having an ideal or excessively formal meaning unless explicitly defined in the present invention.

31 Inert Gas Hose
32 Purge Paper
33 Purge Tape
34 pipe to be welded
41 welding torch
42 stoppers (e.g. sponges)
43 Butt joint gap
51 Super layer welding
52 Back Bead Appearance
61 Belt support
62 Belt left and right movement device
63 wire length adjuster
64 wire rope (e.g. stainless 3.0ø)
65 binner
66 belts (e.g. fiberglass)
71 Welding Torch
72 coil spring
73 Belt length adjuster
74 spring hook
731 Belt Fixing Lever
7311 open direction
7312 closing direction
81 Belt positioning device
82 Nuts
83 Belt shifting device
84 Wire rope length adjustment device (Example: Butterfly bolt)
85 Belt movement direction
91 Wiener for connection (eg 6mm)
92 belt loop
93 Belt extension
94 Pipe rotation direction
1101 Length Adjuster Case
1102 Retaining Lever Teeth
1103 Retaining Lever Pin
1104 plane
1105 side
1106 front
1301 floor plan
1302 side view
1401 wire feeder
1402 pressure roller
1403 Pipe Rotation Drive Roller
1404 Rotator (4-40”)
1405 Pipe rotation direction
1406 wire fixing hook
1501 connector plane
1502 connector side
Belt covering 1503 pipe butt joints
1504 Elastomer Connection
1505 Welding space inside the belt

Claims (3)

In an apparatus for preventing leakage of purge gas for welding, which is supplied in the process of root path welding of a pipe butt joint by a welding apparatus including a pipe rotating device and a welding torch,
Belts having a width and fastened in a circular shape along the joint;
an opening formed in the belt to allow the torch to access the seam;
An elastic part for contracting the belt fastened in a circle; and
and a holding part extending from the belt and fixing the belt to a surrounding fixed object.
The elastic part maintains close contact between the pipe and the belt along the joint,
The holding part is an apparatus for preventing leakage of purge gas for welding to maintain the position of the opening by applying tension in the opposite direction to the rotational direction of the pipe. According to claim 1,
The opening is a purge gas leakage prevention device for welding, characterized in that the space formed between the elastic portion connecting both ends of the belt by two elastic bodies. According to claim 1,
The opening is formed by cutting a part of the belt,
The elastic part is an apparatus for preventing leakage of purge gas for welding, characterized in that it is formed by connecting both ends of the belt with an elastic body.

Images