JP2002086296A - Sealing device used for welding of tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device capable of completely preventing gas leakage from an existing pipe by its high gastightness, and being easily inserted in or drawn out of the pipe. SOLUTION: This sealing device used for welding pipes for preventing leakage of gas or the like from the existing pipe 2 when connecting and welding a new pipe 3 to the existing pipe 2 comprises a wheel 12 in which the outside diameter thereof is smaller than the inside diameter of the pipes 2 and 3, two wheels 12 formed of airtight, substantially circular plates are continuously arranged with predetermined spaces, and the wheels 12 are connected to each other in the axial direction thereof via a connection bar 13, a tube 15 fitted to the circumference of each wheel 12 of the device body 14, and a feed/exhaust pipe 16 for feeding/exhausting the gas in/from each tube 15. Each tube 15 is fed with the gas and inflated to allow the surface of the tube 15 to be tightly fitted to inner wall surfaces of the pipes 2 and 3 so as to heighten gastightness of the pipes 2 and 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding technique for pipes, and more particularly, to preventing a gas leak in a pipe when connecting a new pipe to an existing pipe by connecting the pipe to the existing pipe, thereby enabling easy handling. The present invention relates to a sealing device used for pipe welding.

[0002]

2. Description of the Related Art Conventionally, in a plant having a large number of pipes, a new pipe may be connected to an existing pipe when performing an extension work. Existing pipes and new pipes are arranged and welded at intervals of several millimeters inside the pipes. Since the welding of the joint of the pipe is usually performed only from the outer surface, in order to prevent the occurrence of a welding defect on the inner surface of the pipe, a backwash is formed such that the weld metal swells from the inner surface of the pipe.

At the time of such welding, a valve in the middle of the existing pipe has been closed so that the gas or liquid currently being transported does not flow out. However, when high-pressure gases are being transported, these gases may leak, though only slightly, by closing this valve. If this gas is a flammable substance, when the pipes are welded at intervals of several millimeters as described above, the sparks may ignite and explode, which is very dangerous. In addition, even if it is not a flammable gas, there is a possibility that a dust explosion may be caused when the granular material is transported.

Therefore, when a new pipe is welded to an existing pipe, a so-called rubber balloon having a spherical rubber film filled with air is inflated and packed, so that flammable gas or the like does not leak from the existing pipe. Had been welded. When this connection welding is completed, bleed air from the inside of the rubber balloon,
A balloon-type sealing device that draws out from inside a pipe has been proposed.

Further, as shown in FIG. 4, a sponge-type sealing device 1 using a sponge material instead of a rubber balloon has been proposed. The sponge-type sealing device 1 includes a pipe 2,
A circular or spherical sponge material 4 having an outer diameter longer than the inner diameter of 3 is sandwiched between two circular sandwich plates 5 having an outer diameter shorter than the inner diameter of the pipes 2 and 3 to form a substantially disc-shaped. The sponge material 4 protrudes from the periphery of the two sandwich plates 5 in a ring shape. Two sets of these were arranged in parallel, and were connected by connecting rods 6 at predetermined intervals. The sponge-type sealing device 1 is disposed at a joint between the existing pipe 2 and the new pipe 3 so that the periphery of each sponge material 4 is in close contact with the inner wall of the existing pipe 2 and the new pipe 3. Then, the ring-shaped sponge material 4 portion increases the airtightness in each of the pipes 2 and 3 so that the flammable gas or the like does not leak from the existing pipe 2 to the welded portion.

Further, a gas supply pipe 7 for supplying an inert gas such as argon Ar is penetrated and fixed to the sandwiching plate 5 on the new pipe 3 side. By supplying an inert gas from the gas supply pipe 7 to the joint between the pipes 2 and 3, it is possible to prevent the inner wall surfaces of the pipes 2 and 3 from being carbonized when welding the low-temperature pipe, and to safely secure this joint. We had to be able to weld.

[0007]

However, in the above-mentioned conventional method of inflating and filling a rubber balloon into an existing pipe, about 3
Since the rubber balloon can only be inflated at about the atmospheric pressure, sufficient airtightness cannot be maintained, and there has been a problem that gas leakage from the existing piping cannot be completely prevented.

Further, in the sponge-type sealing device 1, since the air bubbles of the sponge material 4 are not completely independent air bubbles, sufficient airtightness cannot be maintained, and gas leakage from the existing pipe 2 is completely prevented. There was a problem that it was not possible. Furthermore, in the sponge-type sealing device 1, unlike the balloon-type sealing device, the outer diameter of the sponge material 4 cannot be expanded or contracted, so that the sponge-type sealing device 1 can be easily inserted into the pipes 2 and 3. Can not be inserted into
It could not be easily pulled out after the end of welding.

Further, in the sponge-type sealing device 1, when the sponge material 4 is inserted into or pulled out of the pipes 2, 3, a part of the sponge material 4 may be chipped. There is a problem that various inconveniences occur in the subsequent use of the pipes 2 and 3, such as remaining in the pipe and the foreign matter clogging the valve.

The present invention has been made to solve such a problem. That is, an object of the present invention is to provide a sealing device used for pipe welding that can completely prevent gas leakage from an existing pipe due to high airtightness and can easily insert and withdraw a sealing device into a pipe. Is to provide.

[0011]

According to the present invention, when connecting and welding a new pipe (3) to an existing pipe (2), leakage of gas or the like from the existing pipe (2) is prevented. Sealing device used for welding pipes, the pipe (2,
Two wheels (12) made of a substantially circular plate material having an outer diameter shorter than the inner diameter of (3) and having airtightness are arranged side by side at predetermined intervals, and the wheels (12) are connected to the connecting rod in the axial direction thereof. The apparatus body (14) connected by (13), the tubes (15) attached around each wheel (12) of the apparatus body (14), and the supply and exhaust of gas into and from each tube (15). An exhaust pipe (16), a gas is supplied into each of the tubes (15) to expand the tubes, and the surfaces of the tubes (15) are brought into close contact with the inner walls of the pipes (2, 3). A sealing device used for pipe welding, characterized in that the airtightness in (2) and (3) is enhanced.

A gas exhaust pipe (17) for exhausting gas leaking from the existing pipe (2) can be provided on a side surface of a wheel (12) constituting the apparatus body (14) so as to penetrate therethrough. .

A gas supply pipe (18) for supplying an inert gas between the two wheels (12) is provided on a side surface of the wheel (12) constituting the apparatus body (14) so as to penetrate therethrough. be able to.

Further, a tire (1) is attached to the tube (15).
It is also possible to cover 9).

In the construction of the invention described above, the sealing device (11)
Are inserted into the existing pipe (2) and the new pipe (3) so as to connect them, and each tube (15) mounted around the wheel (12) on the inner wall surface of the pipe (2, 3). Existing pipes (2) and new pipes (3)
Installed so that it touches the inner wall. At this position, air or the like is supplied from a supply / exhaust pipe (16) into each tube (15) to expand the tube (15), and the two pipes (2,
The surface of the tube (15) is brought into close contact with the inner wall surface of (3), and the airtightness in the pipe (2, 3) can be increased. It is possible to prevent flammable gas and the like from leaking from the existing pipe 2 to the welded portion. Therefore, when a new pipe (3) is welded and connected to the existing pipe (2), a welding operation can be performed safely without igniting even if a spark comes out.

When the welding operation is completed, the tube (15)
Air or the like is extracted from the inside, the diameter of the tube (15) is reduced, and a gap is formed between the inner wall surface of each pipe (2, 3) and the surface of the tube (15). The sealing device (11) can be smoothly pulled out from both pipes (2, 3). Then, the surface of the tube (15) is caught on the inner wall surface of the pipe (2, 3), and fragments of the tube (15) are
The problem of remaining in 3) does not occur.

Further, a sealing device (1) is provided in the pipe (2, 3).
Even when 1) is fixed, flammable gas leaking from the gas exhaust pipe (17) to the existing pipe (2) can be exhausted to the outside of the new pipe (3). Even when it takes a long time, it is possible to work safely.

Further, an inert gas such as argon (Ar) can be supplied from a gas supply pipe (18) penetrating the wheel (12) on the side of the new pipe (3). Can prevent carbonization of the inner wall surface of the pipe (2, 3).

Further, a tire (19) is attached to the tube (15).
In the case of the tire (19), the so-called tread surface (19a) of the tire (19) closely adheres to the inner wall surface of the pipe (2, 3) in a wide range, so that the airtightness can be further improved. Further, since the inside of the tire (19) is protected by the carcass (19d), even if the tube (15) is filled with high-pressure air,
It does not break easily.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the drawings, common members are denoted by the same reference numerals, and redundant description is omitted. FIG.
1 is a sectional view showing an embodiment in which a sealing device used for pipe welding according to the present invention is inserted into a pipe. FIG. 2 is an enlarged sectional view showing an expanded state of the tube. The sealing device 11 used for pipe welding according to the present invention is used to prevent leakage of flammable gas and the like from the existing pipe 2 when connecting and welding a new pipe 3 to the existing pipe 2. . The sealing device 11 includes a device main body 14 in which two wheels 12 are arranged side by side at predetermined intervals and connected by a connecting rod 13 in the axial direction of the wheels 12, a tube 15 attached around each wheel 12, A supply / exhaust pipe 16 is provided.

The apparatus main body 14 is used for connecting each of the pipes 2 and 3 when performing an extension work for connecting a new pipe 3 to the existing pipe 2.
Two wheels 12 made of a substantially circular plate material 12a having an outer diameter shorter than the inner diameter and having airtightness are arranged in parallel like a vehicle wheel at a predetermined interval. Both wheels 12 are connected by a connecting rod 13 in the axial direction. If there are three connecting rods 13, for example, the wheel 12
Can be maintained in a parallel state. The reason why the two wheels 12 are arranged in parallel in the present invention is that when the sealing device 11 is inserted into the pipes 2 and 3, the surface of the tube 15 is perpendicular to the inner wall surfaces of the pipes 2 and 3. This is to increase the airtightness. For example, if the number of wheels is one, it may be inclined in the pipes 2 and 3 so that the entire circumference of the tube 15 may not evenly hit the inner wall surfaces of the pipes 2 and 3.

The tube 15 is, for example, a rubber ring. A gas such as air is supplied to and exhausted from the outside of each tube 15 via a supply / exhaust pipe 16.

On the side surface of the wheel 12 constituting the apparatus main body 14, a gas exhaust pipe 17 for exhausting flammable gas leaking from the existing pipe 2 is provided so as to penetrate therethrough. The gas exhaust pipe 17 discharges flammable gas and the like leaking from the existing pipe 2 to the outside of the new pipe 3 so as to enable safe operation even when a long time is required for welding. is there.

Further, the wheel 1 constituting the apparatus body 14
The two side surfaces are provided so as to pass through a gas supply pipe 18 for supplying an inert gas toward between the two wheels 12. The gas supply pipe 18 is for preventing the inner wall surfaces of the pipes 2 and 3 from being oxidized, for example, when welding a low-temperature pipe.

The sealing device 11 of the present invention is designed to
And the new pipe 3 are inserted so as to connect them, and the surfaces of the tubes 15 attached around the wheel 12 to the inner wall surfaces of the pipes 2 and 3 are respectively connected to the existing pipe 2 and the new pipe 3. Install so that it is perpendicular to the wall. At this position, air or the like is supplied from the supply / exhaust pipe 16 into each tube 15 to expand the tube 15 and
The surface of the tube 15 is brought into close contact with the inner wall surface. At this time, as shown in FIG.
As shown in the arrow, the pressure of
2, the airtightness of the existing pipe 2 can be enhanced.

As described above, the sealing device 11 of the present invention
The airtightness in the pipes 2 and 3 can be improved, and the leakage of combustible gas and the like from the existing pipe 2 to the welded portion can be prevented. Further, since flammable gas and the like leaking from the gas exhaust pipe 17 to the existing pipe 2 can be exhausted to the outside of the new pipe 3, when welding the existing pipe 2 and the new pipe 3, a spark is generated. Even if it comes out, welding work can be performed safely without ignition.

After the welding operation is completed, air or the like is extracted from the tube 15, the diameter of the tube 15 is reduced,
A gap is formed between the inner wall surface of each of the pipes 2 and 3 and the surface of the tube 15. The sealing device 11 can be smoothly pulled out from both the pipes 2 and 3. Therefore, the problem that the surface of the tube 15 is caught on the inner wall surfaces of the pipes 2 and 3 and pieces of the tube 15 remain in the pipes 2 and 3 does not occur.

When the inner wall surface of the pipe is easily oxidized during welding, such as a low-temperature pipe, an inert gas such as argon (Ar) is supplied from the gas supply pipe 18 to the joint between the pipes 2 and 3. Thereby, carbonization of the inner wall surfaces of the pipes 2 and 3 can be prevented.

FIG. 3 is a cross-sectional view showing another embodiment of the invention in which a tube is covered with a tire. Tube 15 contains
The tire 19 can be covered. The tire 19 has a structure similar to that used for, for example, an automobile or a bicycle. The tire 19 has a tread surface 19a on the grounding surface (in the present invention, the inner wall surface of the pipe), and a side portion 19b and a wheel 1
2 and a bead portion 19c that fits in the second portion. In addition, the tire 19 made of rubber is provided with a carcass 19d for enhancing the reinforcing effect inside.

By covering the tube 15 with the tire 19 thus configured, its tread surface 19a
The airtightness can be further improved by closely adhering to the inner wall surfaces of the pipes 2 and 3 over a wide range. Further, since the inside of the tire 19 is protected by the carcass 19d, even if the tube 15 is filled with high-pressure air, it is not easily damaged.

Even if the tire 19 is a so-called tubeless type, there is no problem as long as the adhesion between the tread surface 19a and the inner wall surfaces of the pipes 2 and 3 is good.

It should be noted that the present invention is not limited to the above embodiment, but has been described with reference to an embodiment in which two wheels 12 are configured as one set. If the surface of the tube 15 or the tire 19 is brought into close contact with the inner wall surfaces of the pipes 2 and 3 to increase the airtightness in the pipes 2 and 3, the two wheels 12 described above are used.
Is not limited to a single set, and the wheel 12 may be formed into various shapes by combining only one wheel or three or more wheels. Therefore, various changes may be made without departing from the gist of the present invention. Obviously you can get it.

[0033]

As described above, the sealing device used for welding pipes according to the present invention is inserted into existing pipes and new pipes, and supplies air or the like from supply / exhaust pipes to expand the surface of each expanded tube. By adhering to the inner wall surfaces of both pipes, the airtightness inside the pipes is increased, and flammable gas and the like can be prevented from leaking from the existing pipes to the welded parts, and sparks appear during welding. Work can be performed safely without ignition. When the welding work is completed, if the air or the like is extracted from the inside of the tube, this sealing device can be smoothly pulled out from both pipes, and the surface of the tube or tire is caught on the inner wall of the pipe, and fragments thereof remain in the pipe. This does not occur.

Further, since flammable gas or the like leaking from the gas exhaust pipe to the existing pipe can be exhausted, it is possible to work safely even when welding requires a long time. When the low-temperature pipe is connected, the inert gas can be supplied from the gas supply pipe, so that it is possible to prevent the inner wall surface of the pipe from being carbonized during welding.

Further, when the tube is covered with a tire,
The tread surface adheres widely to the inner wall surface of the pipe, and even if the tube in the tire is filled with high-pressure air, it does not break easily, so it can be filled with high-pressure air, so the gas leaking from the existing pipe Can be reliably prevented.

Also, if air or the like is extracted from the inside of the tube, the sealing device can be smoothly pulled out from both pipes, and the surface of the tube does not get caught on the inner wall surface of the pipe. And other excellent effects.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment in which a sealing device used for welding a pipe according to the present invention is inserted into a pipe.

FIG. 2 is an enlarged sectional view showing an expanded state of a tube.

FIG. 3 is a sectional view showing another embodiment of the invention in which a tube is covered with a tire.

FIG. 4 is a cross-sectional view showing a state where a conventional sponge-type sealing device is inserted into a pipe.

[Explanation of symbols]

 2 Existing piping 3 New piping 11 Sealing device 12 Wheel 12a Bead portion 13 Connecting rod 14 Device body 15 Tube 16 Supply / exhaust pipe 17 Gas exhaust pipe 18 Gas supply pipe 19 Tire

Continued on the front page (72) Inventor Norihiko Suzuki 3-2-16-1 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries, Ltd. Tokyo Engineering Center (72) Inventor Hiroto Ikeda 3-2-16-1 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries, Ltd. Tokyo Engineering Center (72) Inventor Naoki Yasuda 3-2-1, Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries, Ltd. Tokyo Engineering Center F-term (reference) 4E081 YX02 YX13 YY11

Claims (4)

[Claims] When a new pipe (3) is connected and welded to an existing pipe (2), the sealing apparatus is used for pipe welding for preventing leakage of gas and the like from the existing pipe (2). In addition, two wheels (12) made of a substantially circular plate material having an outer diameter shorter than the inner diameter of the pipe (2, 3) and having airtightness are arranged in parallel at a predetermined interval, and the wheels (1) are arranged in parallel.
2) The main body (14) of the main body (14), which is connected with the connecting rod (13) in the axial direction, and each wheel (12) of the main body (14).
And a supply / exhaust pipe (16) for supplying and exhausting gas into and from each tube (15), and supplying and expanding gas into each of the tubes (15). ,
A seal used for pipe welding, characterized in that the surface of the tube (15) is brought into close contact with the inner wall surface of the pipe (2, 3) so as to increase the airtightness in the pipe (2, 3). apparatus. 2. A gas exhaust pipe (17) for exhausting gas leaking from the existing pipe (2) is provided on a side surface of a wheel (12) constituting the apparatus body (14) so as to penetrate therethrough. The seal device used for pipe welding according to claim 1, characterized in that: 3. A gas supply pipe (18) for supplying an inert gas between two wheels (12) so as to pass through a side surface of a wheel (12) constituting the apparatus body (14). The sealing device used for welding pipes according to claim 1 or 2, wherein 4. A tire (19) in said tube (15).
The sealing device used for pipe welding according to claim 1, 2 or 3, wherein