JPH08309529A - Piping welding back shield device - Google Patents

Abstract

PURPOSE: To provide a piping welding back shield device capable of forming a back shield inside a piping by inserting an integrated balloon and facilitating the pressure control in the back shield. CONSTITUTION: This piping welding back shield device is the integrated balloon 4 in which a front balloon 4a to open a diffuser 5 at the rear side and a rear balloon 4b to open an exhaust tube 6 at the front side, to penetrate the inside an to connect the blast tube 10 at the rear side are joined a the necking part, in a back shield device to form a space 12 nearby the welding line 3 inside the piping in a time of welding pipings 1, 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe welding operation,
In particular, the present invention relates to a pipe welding back shield device for forming an appropriate back shield in a welded portion.

[0002]

2. Description of the Related Art Conventionally, when connecting pipes by welding, there is a method in which an inert gas is filled in the pipes in advance in order to improve the reliability of the welding and then the welding work is performed from the outer periphery. In this way, when it is necessary to fill the inside of the pipe with an inert gas, one or both sides of the pipe to be welded is closed with a film or balloon, and a space is formed on the back side of the welded portion to prevent the inert gas from flowing. It was filling.

[0003]

However, the work of forming the space is troublesome, and it is difficult to control and control the internal pressure in the space formed inside the pipe during the welding of the pipe. Also, if the contained fluid remains in the pipe, welding work cannot be performed as it is.
There is a problem that it takes time to eliminate this.

Further, in order to form a space for back shield inside the pipe, it is necessary to seal the welding line at two places. Especially, when the pipe to be welded is long, the state of the seal portion is confirmed. It was extremely difficult.

An object of the present invention is to form a back shield in a pipe by inserting an integrated balloon, and
An object of the present invention is to provide a back shield device for pipe welding, which facilitates pressure management in the back shield.

[0006]

In order to achieve the above object, a back welding apparatus for pipe welding according to the invention of claim 1 forms a space in the vicinity of a welding line inside the pipe when welding the pipe. In the device, a front balloon with an outlet opening on the rear side and a balloon with an exhaust pipe opening on the front side that penetrates the inside and an air supply pipe is connected to the rear side are connected together at the constricted part with a constricted balloon. It is characterized by being.

A pipe welding back seal device according to a second aspect of the present invention is characterized in that the constricted portion of the balloon is covered with a heat-resistant cover. A back welding device for pipe welding according to a third aspect of the present invention is characterized in that the constricted portion of the balloon is formed of a heat resistant tube.

A back welding device for pipe welding according to a fourth aspect of the present invention is characterized in that the outer circumferences of the front balloons and the rear balloons of the balloons are subjected to slipping processing. A back welding device for pipe welding according to a fifth aspect of the present invention includes a drain pipe which is opened in front of the balloon in front of the balloon and penetrates the inside of the balloon.

According to a sixth aspect of the present invention, there is provided a pipe welding back seal device characterized in that an endoscope is provided outside a constricted portion of a balloon. According to a seventh aspect of the present invention, there is provided a pipe welding back seal device, which is an integrated balloon in which a blowout port and an exhaust pipe penetrating the inside are opened on the front side and an air supply pipe is connected on the rear side. To do.

In the back welding device for pipe welding according to the present invention, the oxygen concentration measuring device, the pressure measuring device and the pressure adjusting device are connected to the exhaust pipe penetrating the balloon after the balloon, and the pressure in the internal space of the pipe is connected. It is characterized by controlling both and / or oxygen concentration.

[0011]

According to the first aspect of the present invention, the constricted portion of the balloon integrated with the welding line of the pipe is located, and the front balloon and the rear balloon on both sides are inflated to seal the inside of the pipe and to the back side of the welding line. A space inside the pipe is formed.

According to the second aspect of the present invention, since the constricted portion of the balloon facing the welding line is covered with the heat-resistant cover, the balloon is not damaged by the welding heat. The invention according to claim 3 is
Since the constricted part of the balloon is a heat resistant tube, it will not be damaged by welding heat.

According to the fourth aspect of the present invention, since the balloons do not slip in the pipe due to the slip-on processing applied to the outer circumferences of the front balloon and the rear balloon, it is easy to maintain the space in the pipe and the state. According to the fifth aspect of the invention, even if the fluid remains on the front surface of the front balloon, the fluid can be discharged by the drain pipe, so that the fluid can be removed, and welding can be performed while removing the fluid.

According to the sixth aspect of the present invention, the state of the space inside the pipe can be monitored by the endoscope even during the welding operation. In the invention according to claim 7, when one of the pipes is first stopped, an integrated balloon is inserted into the pipe on the open side, the inside of the pipe is sealed before the welding line, and the back side of the welding line is easily formed. A space inside the pipe can be formed.

According to an eighth aspect of the present invention, the oxygen concentration measuring instrument connected to the exhaust pipe detects the oxygen concentration and the pressure measuring instrument detects the pressure, and the pressure regulator adjusts the pressure in the space inside the pipe and the oxygen concentration. Highly reliable welding can be performed by controlling both conditions or both conditions.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. In the first embodiment, as shown in the vertical cross-sectional view of FIG. 1A, one end of each of two pipes 1 and 2 whose both ends are open is abutted against each other. The rubber-made integral balloon 4 including the two front balloons 4a, the rear balloons 4b, and the constricted portion 4c is inserted with the welding line 3 interposed therebetween.

In this balloon 4, the front balloon 4a has a plurality of outlets 5 open to the rear side, the rear balloon 4b has an exhaust pipe 6 open to the front, and the exhaust pipe 6 has a rear balloon 4b. An oxygen concentration measuring device 7, a pressure measuring device 8 and a pressure adjusting device 9 are connected to the rear outside through the inside.

Further, after this, an air supply pipe is provided on the rear side of the balloon 4b.
10 is connected and externally coupled to the inert gas supply device 11 to form a pipe welding back shield device. 1 (b) is a sectional view taken along the line AA of FIG. 1 (a) showing the arrangement of the outlets 5, and FIG. 1 (c) is a sectional view taken along the line BB of FIG. 1 (a) showing the exhaust pipe 6. The open state is shown.

Next, the operation of the above configuration will be described. The balloon 4 is inserted into the inside of the two pipes 1 and 2 arranged at one end of each other, and the welding line 3 is sandwiched between the front balloon 4a and the rear balloon 4b, so that the constricted portion 4c faces the welding line 3. To do.

When the inert gas is supplied from the inert gas supply device 11 through the air supply pipe 10, the inert gas is supplied to the rear balloon 4.
b, the constricted portion 4c, and the front balloon 4a are sent in this order to inflate the entire balloon 4 including the front balloon 4a, the constricted portion 4c, and the rear balloon 4b.

As a result, the outer circumference of the front balloon 4a presses against the inner circumference of the pipe 1 and the outer circumference of the rear balloon 4b presses against the inner circumference of the pipe 2 to seal them, thereby forming the constricted portion 4c and the welding line 3. A pipe inner space 12 which is a back shield is formed between them.

Inert gas is blown into the pipe inner space 12 from the outlet 5 of the front balloon 4a, and the air in the pipe inner space 12 is discharged to the outside through the exhaust pipe 6,
It is replaced with an inert gas.

During ventilation by the exhaust pipe 6, the oxygen concentration is measured by the oxygen concentration measuring device 7 and the pressure is measured by the pressure measuring device 8. According to the pressure measured by the pressure measuring device 8, the pressure is measured. By controlling the exhaust gas amount or the supply amount of the inert gas from the inert gas supply device 11 by the adjuster 9, the pressure and oxygen concentration of the inert gas in the pipe internal space 12 are suitable for welding from the outer circumference. Maintained in a state.

In this state, welding work is performed from the outer circumferences of the pipes 1 and 2 to the welding line 3, so that highly reliable pipe connection can be achieved. In addition, here front balloon 4
a and the outer circumference of the rear balloon 4b are non-slip by rough surface processing
By applying 13, the balloon 4 is prevented from moving in the axial direction.

In the second embodiment, as shown in the longitudinal sectional view of FIG. 2, the outer periphery of the constricted portion 4c of the balloon 4 is covered with a heat resistant cover 14 to form a pipe welding back shield device. The other components are the same as those in the first embodiment.

The operation of the above construction is as follows:
When performing a welding operation from the outer periphery along the welding line 3 with respect to 2, the heat transferred from the welding line 3 to the pipe inner space 12 is shielded by the heat resistant cover 14, so that the balloon 4 may be damaged. It can be prevented. The other functions and operating methods are the same as those in the first embodiment.

As shown in the longitudinal sectional view of FIG. 3, the third embodiment is a modification of the second embodiment described above, in which the balloon 15 is located at the constricted portion between the two balloons, the front balloon 15a and the rear balloon 15b. It is configured by connecting a heat resistant pipe 16 of iron or ceramics.

With respect to the operation and effect of this structure, the same thing as the second embodiment can be obtained, but the heat resistance of the constricted part by the heat resistant pipe 16 is determined by selecting the material of the heat resistant pipe 16. Higher heat resistance can be obtained than in the examples.

In the fourth embodiment, as shown in the longitudinal sectional view of FIG. 4A and the sectional view taken along the line CC of FIG. 4B, the fluid remains in one of the pipes 2. It applies when there is
The balloon 17 is opened to the front of the front balloon 17a, and a drain pipe 18 penetrating the front balloon 17a, the constricted portion 17c, and the rear balloon 17b is provided to form a back welding device for pipe welding. The other components are the same as those in the first embodiment.

As a function of this structure, the fluid contained in the pipe 2 and sealed by the front balloon 17a and remaining at the time of welding passes through the front balloon 17a and the rear balloon 17b as shown by the dotted arrow 19, and the drain pipe. It is discharged to the outside via 18.

Thus, the pipe 1 and the pipe 2 can be welded with a slight amount of fluid remaining in the pipe 2. The other functions and operating methods are the same as those in the first embodiment.

In the fifth embodiment, as shown in the longitudinal sectional view of FIG. 5, the endoscope 20 is provided outside the constricted portion 4c of the balloon 4 arranged in the pipes 1 and 2, and the pipe is a back shield. A back shield device for pipe welding is constructed, which allows the condition inside the internal space 12 to be confirmed from the outside via the exhaust pipe 6. In addition,
The other components are the same as those in the first embodiment.

The operation of this structure is as follows: the state of the back shield in the pipe inner space 12, that is, the balloon 4
The welding operation can be performed while the arrangement state in the pipes 1 and 2 and the state on the back side of the welding line 3 at the time of welding are monitored from the outside by the endoscope 20 via the exhaust pipe 6. The other operations and operating methods are the same as those in the first embodiment.

As shown in the longitudinal sectional view of FIG. 6, the sixth embodiment is a modification of the fifth embodiment, in which the endoscope 20 is installed on a support ring 21 provided on the outer circumference of the constricted portion 4c of the balloon 4. And constitutes a back shield device for pipe welding. The other components are the same as those in the first embodiment.

With the above structure, the endoscope 20 can be installed firmly, so that the inside of the pipe 12, which is the back shield, including the surface of the balloon 4 can be monitored more satisfactorily. The other actions and operating methods are the same as those in the first embodiment.

In the seventh embodiment, as shown in the vertical sectional view of FIG. 7A, the balloon 22 is a front balloon 4a similar to that of the first embodiment.
This is a back shield device for pipe welding, which is composed of a front balloon 22a having the same shape as the above, a rear balloon 23b provided with an exhaust pipe 23 and an air supply pipe 10 penetrating therethrough, and a constricted portion 22c.

7 (b) is a sectional view taken along the line DD of FIG. 7 (a), and FIG. 7 (c) is a sectional view taken along the line EE of FIG. 7 (a).
The function of the above configuration is that the diameter of the exhaust pipe 23 of the rear balloon 23b,
By adjusting the amount of the inert gas supplied from the inert gas supply device 11 through the air supply pipe 10, the oxygen concentration measuring device 7 and the pressure measuring device 8 and the pressure adjusting device shown in the first embodiment and the like. It has a simple structure without using 9 or the like, and can manage the pipe internal space 12 which is a back shield in a good state at the time of welding work on the welding line 3.

The eighth embodiment, as shown in the longitudinal sectional view of FIG. 8, is a back shield for pipe welding suitable for the case where one pipe 24 is first stopped or is closed by a not-shown closing lid or the like. It is a device.

Balloon to be inserted in the pipe 1 before the welding line 3
25 is a single body, and is provided with a plurality of air outlets 5 that are open to the front side, and an exhaust pipe 6 that is also open to the front side and penetrates the inside of the balloon 25. Furthermore, an air supply pipe 10 is connected to the rear side of the balloon 25, and an inert gas supply device 11 is connected to the outside.

An oxygen concentration measuring instrument 7, a pressure measuring instrument 8 and a pressure regulator 9 are connected to the exhaust pipe 6 outside. Next, the operation of the above configuration is that the balloon 25 is inserted into the pipe 1 from the open end of the pipe 1 and is arranged in front of the welding line 3 between the pipe 1 and the stopper pipe 24,
The inside of the pipe 1 is sealed by supplying an inert gas from the inert gas supply device 11 and expanding the same.

As a result, the pipe inner space 12 which is the back shield by the stopper pipe 24, the inside of the pipe 1 and the balloon 25.
To form. According to the eighth embodiment, the pipe inner space 12
Since only one balloon 25 having a simple shape is required to form, and by arranging the balloon 25 slightly apart from the welding line 3, the balloon 25 is not damaged by the heat generated by the welding operation.

Further, there is a large margin in the accuracy of the installation position, and therefore the installation work is easy. The effect of forming the back shield is similar to that of the first embodiment.

[0043]

As described above, according to the present invention, the inside space of the pipe, which is the back shield, is formed in the pipe at the time of welding the pipe with a simple device, and the inert gas pressure and the oxygen concentration in the inside can be easily adjusted and monitored. Thus, highly reliable pipe welding can be performed.

[Brief description of drawings]

FIG. 1 is a back shield device for pipe welding according to a first embodiment of the present invention, in which (a) is a vertical sectional view, (b) is a sectional view taken along the line AA, and (c) is B of (a). -B arrow sectional drawing.

FIG. 2 is a vertical sectional view of a second embodiment according to the present invention.

FIG. 3 is a vertical sectional view of a third embodiment according to the present invention.

FIG. 4 is a longitudinal sectional view of the fourth embodiment according to the present invention, and FIG. 4B is a sectional view taken along line CC of FIG.

FIG. 5 is a vertical sectional view of a fifth embodiment according to the present invention.

FIG. 6 is a vertical sectional view of a sixth embodiment according to the present invention.

7 (a) is a longitudinal sectional view, FIG. 7 (b) is a sectional view taken along the line DD of FIG. 7 (a), and FIG. 7 (c) is an arrow E-E of FIG. 7 (a). Sectional view.

FIG. 8 is a vertical sectional view of an eighth embodiment according to the present invention.

[Explanation of symbols]

1, 2 ... Piping, 3 ... Welding line, 4, 15, 17, 22, 25 ... Balloons, 4a, 15a, 17a, 22a ... Front balloons, 4b, 15b, 17
b, 22b ... rear balloon, 4c, 17c, 22c ... constricted portion, 5 ...
Air outlets, 6, 23 ... Exhaust pipes, 7 ... Oxygen concentration measuring device, 8 ... Pressure measuring device, 9 ... Pressure adjusting device, 10 ... Air feeding pipe, 11 ... Inert gas supply device, 12 ... Pipe inner space, 13 ... Anti-slip, 14 ...
Heat-resistant cover, 16-heat-resistant pipe, 18-drainage pipe, 19-dotted arrow (fluid), 20 endoscope, 21-support ring, 24-stop pipe.

Claims (8)

[Claims] 1. A back shield device for welding a pipe, wherein a space is formed in the vicinity of a welding line inside the pipe during welding of the pipe, in which a front balloon having a blowout opening on the rear side and an exhaust pipe on the front side are opened. A back shield device for pipe welding, characterized in that it is an integrated balloon in which a balloon is penetrated through and an air supply pipe is connected to the rear side, and the balloon is connected at a constricted portion. 2. The back shield apparatus for pipe welding according to claim 1, wherein the constricted portion of the balloon is covered with a heat resistant cover. 3. The back shield apparatus for pipe welding according to claim 1, wherein the constricted part of the balloon is formed of a heat-resistant tube. 4. The back shield apparatus for pipe welding according to claim 1, wherein the outer circumferences of the front balloon and the rear balloon of the balloon are subjected to slip fitting processing. 5. The back shield apparatus for pipe welding according to claim 1, further comprising a drainage pipe which is opened on the front side of the balloon in front of the balloon and penetrates the inside of the balloon. 6. The pipe welding back shield apparatus according to claim 1, further comprising an endoscope provided outside the constricted portion of the balloon. 7. A back shield device for pipe welding, comprising a blow-out port on the front side, an exhaust pipe penetrating the inside thereof, and an air balloon connected to the rear side, which is an integral balloon. 8. An oxygen concentration measuring device, a pressure measuring device and a pressure adjusting device are connected to an exhaust pipe penetrating the balloon after the balloon,
The pipe welding back shield device according to any one of claims 1 to 7, wherein both the pressure and the oxygen concentration in the pipe inner space are controlled, or both of them are controlled.