JPH0771685A - Gas shutoff device for pipe unit - Google Patents

Abstract

PURPOSE:To improve reliability of pipe line shutoff by providing the first seal means removably mounted on a pipe unit internal wall and the second seal means formed of a seal bag unit provided in the front in a pipe unit from the first seal means and inflated by introducing gas to shut off inside the pipe unit. CONSTITUTION:In the case of mounting a shutoff device 18, first into a pipe unit 15 from its opening end, a total unit of the shutoff device 18 is inserted and fixed by tightening stopper bolts 23.... Next, a gas introducing pipe 26 is pressed in by a some degree to separate a closing plate 21 from a seal bag unit 27, and by feeding inflating gas from a base end side of the gas introducing pipe 26, the seal bag unit 27 is inflated to close the inside of the pipe unit 15. This shutoff device 18 has a closing member 19 inserted into the pipe unit 15 from its opening end and removably mounted, and this closing member is formed by providing a pipe seal unit 24 in a closing plate 21 provided in the point end part of a tube part 20 extended in the pipe unit 15, to constitute the first seal means B for performing a seal by hitting an internal peripheral surface of the pipe unit 15 to collapse a peripheral edge part of the pipe seal unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas shut-off device for pipes, and in particular, when remodeling a pipeline system through which flammable gas flows, temporarily shut off the flammable gas to perform a fire work such as welding. The present invention relates to a gas shutoff device for a pipe body that enables the above.

[0002]

2. Description of the Related Art In recent years, there has been a tendency for repair and remodeling work, which also serves as inspection, to increase with the deterioration of a pipeline system through which combustible gas flows. In this case, it is desirable to carry out the work only on the aged part while the combustible gas of a predetermined pressure or a reduced pressure is allowed to flow through the pipeline without stopping the facility. The actual work of this work is to cut the aged pipe part and replace it by welding a new pipe, but this welding work is a fire work, and on the other hand flammable gas is in the pipe work. Since it is sent, apart from the case where a shut-off valve or the like having a high shut-off property is provided, a device for surely and completely shutting off the combustible gas is required before the welding site in the case of remodeling work.

As a device for shutting off the flammable gas in the pipe, it is possible to apply the device shown in FIGS. 3 and 4, for example (Japanese Patent Application No. 5-18321).

These devices are accompanied by the replacement of the flange portion 4 provided on the side nozzle 2 of the storage tank 1 and having the valve 3 attached thereto.
This is an apparatus for performing a pressure resistance / airtightness test of a new welded portion 5 indicated by a dotted line in the figure.

First, in the apparatus shown in FIG. 3, a closing plate 6 attached to an open end of a valve 3 and a side nozzle 2 penetrating the closing plate 6 are provided.
A gas inlet pipe 7 inserted therein, a bag body 8 provided at the tip of the gas inlet pipe 7 and swelling by gas feed to close the inside of the side nozzle 2, a bag body 8 and a closing plate 6. It is mainly composed of a gas injection nozzle 9 provided in the closing plate 6 in order to perform a pressure resistance and airtightness test of the new welded part 5 by enclosing a gas between them. With this configuration, when the inflation gas such as nitrogen gas is fed into the bag body 8 through the gas feed pipe 7 after welding the new flange portion 4, the bag body 8 swells and the inside of the side nozzle 2 is closed, and further gas filling is performed. If a test gas such as nitrogen gas is sealed between the nozzle 9 and the bag body 8 and the closing plate 6 up to a predetermined pressure, the pressure gauge 13 measures the pressure to test the pressure resistance and airtightness of the new welded portion 5. It can be carried out.

Next, in the apparatus shown in FIG. 4, a closing plate 6 attached to the open end of the valve 3 and a through pipe 10 penetrating the closing plate 6 are provided.
And a rod body 1 inserted into the side nozzle 2 via
The closure body 12 is provided at the tip of the first nozzle 1 and has an umbrella structure that is opened and closed by relative movement with the through tube 10 to close the inside of the side nozzle 2.
And a gas sealing nozzle 9 provided in the closing plate 6 for sealing gas between the closing body 12 and the closing plate 6 to perform a pressure-proof / airtight test of the new welded portion 5. This device replaces the bag body 8 of the above-described device with an umbrella-shaped closure 1
Since the inside of the side nozzle 2 is closed by 2, the pressure resistance and airtightness test of the new welded portion 5 can be performed even by using this apparatus.

In the illustrated example, a butterfly valve is used as the valve 3, but any of the above devices can be inserted into the side nozzle 2 through the valve body 14 regardless of the type of the valve 3. Has become.

[0008]

By the way, the above-mentioned device is only for carrying out a pressure resistance / airtightness test on the welded portion 5 after the welding is completed, and the bag body 8 or the closure body 12 is somewhat insufficiently sealed. Also, by forcibly sending the test gas from the gas charging nozzle 9, the new welded portion 5
Can be maintained at a predetermined test pressure. Conversely, the above-mentioned device cannot be expected to have a high gas-blocking performance, and the above-mentioned device cannot be used in consideration of a burning work such as welding performed by closing the pipe body where flammable gas exists. There's a problem.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above problems and to reliably and completely shut off flammable gas and the like in the pipe body, and to perform a fire work such as welding in a safe manner. To provide.

[0010]

In order to achieve the above object, the present invention provides a gas inside the pipe body in the insertion direction in front of the working area of the pipe body where the pipe body is inserted from its open end and welded. A first sealing means that is inserted into the tubular body from the open end, is positioned in front of the tubular body working area, is detachably attached to the inner wall of the tubular body, and shuts off the tubular body. Second sealing means, which is provided in front of the first sealing means in the inside of the tubular body and is expanded by the introduction of gas to shut off the inside of the tubular body, and introduces gas into the second sealing means and A gas introducing pipe for supporting and supporting the second sealing means in front of the first sealing means in the tubular body; and a second sealing means and a first sealing means provided in the first sealing means. Gas leaks between the pipe It is obtained by a leak gas exhaust pipe for exhausting the.

[0011]

When the flammable gas is present in the pipe, the flammable gas is first blocked by the expanded seal bag body or the second sealing means. Further, even if a leak gas is generated from the first sealing means, the leak gas is blocked by the first sealing means this time and is exhausted to the outside through the leak gas exhaust pipe. Therefore, in the above-mentioned device, the exhaust structure is added to the double blocking structure, whereby the combustible gas in the pipe can be reliably and completely blocked.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, in this embodiment, the tube body 15 is the side nozzle 2 (see FIGS. 2 and 3) of the tank body 1 in which the combustible gas 17 is stored, and it has a relatively large diameter. It was formed. A flange 16 is welded to the pipe body 15 at the welded portion 5 which is the work area A. During replacement work due to the deterioration of the flange 16, the flammable gas 17 inside the pipe body 15 leaks to the outside of the pipe body 15. A shutoff device 18 for shutting off is attached to the pipe body 15.

The shutoff device 18 has a closing member 19 which is inserted into the tubular body 15 from its open end, that is, the open end of the flange 16, and is detachably attached. Closing member 1
Reference numeral 9 denotes a tubular portion 20 extending from the open end of the tubular body 15 into the tubular body 15 along the axis thereof, and a flange portion provided at the tip of the tubular portion 20 and having an outer diameter substantially equal to the inner diameter of the tubular body 15. A closing plate 21 having a diameter, and a plurality of (three or more) locking members 22 provided at a substantially intermediate position of the tubular portion 20 so as to project radially outward.
And a stopper bolt 23 screwed to the locking member 22 to fix the closing member 19 by pressing the inner wall of the tubular body 15.

The closing plate 21 of the closing member 19 is provided with a seal body 24 for sealing a gap between the closing plate 21 and the inner peripheral surface of the tube body 15. Specifically, the seal body 24 is a plate material such as rubber formed to have a diameter slightly larger than the inner diameter of the pipe body 15, and the peripheral portion of the seal body 24 abuts against the inner peripheral surface of the pipe body 15 to be crushed to perform sealing. It is a thing. These closing member 19 and sealing body 24
The first sealing means B is constituted by and the inside of the pipe body 15 is shut off by the first sealing means B.

The tubular portion 20 of the closing member 19 has a squeezed proximal end portion, and at the same time, an insertion portion 25 for a gas introduction pipe 26 is formed at the proximal end portion. A seal member 25a is provided on the inner peripheral portion of the insertion portion 25, and the gas introduction pipe 26 is slidably and airtightly inserted. The distal end of the gas introduction pipe 26 is located further forward than the closing plate 21 in the insertion direction, and the distal end of the gas introduction pipe 26 expands due to the introduction of the inflation gas to close the inside of the pipe body 15, which is a seal bag. A body 27 is provided. The seal bag body 27 is specifically a balloon body formed of an elastic body such as rubber, and is deflated as shown by the dotted line in the figure when not filled with inflation gas. Further, the sealing bag 27 is attached to the tubular portion 20 of the closing member 19.
A leak gas exhaust pipe 28 for connecting the leak gas R to the outside of the pipe 15 when the leak gas R is generated is connected. Although not shown, the end portion of the leak gas exhaust pipe 28 is extended to some extent and left outside so that the leak gas R is released by opening to the atmosphere.

In the shut-off device 18 thus constructed, the stopper bolt 23 is located further forward of the welded portion 5 in the tubular body 15.
It is positioned and fixed to the inner wall, and is arranged so as not to interfere with the cutting and re-welding work of the flange 16 in the work area A. Further, in the present embodiment, the tubular portion 20 includes a first tubular portion 20a on the distal end side having a closing plate 21 and a locking member 22 provided at both ends, and a second tubular portion on the proximal end side to which the leak gas exhaust pipe 28 is connected. It is formed by integrally flange joining with 20b. In addition, if a structure is used in which these are bolted and flanged together, various pipe bodies 15 can be handled by exchanging the first cylindrical portion 20a according to the inner diameter of the pipe body 15.

Next, the operation of the embodiment will be described.

As a method of mounting the breaking device 18, first, the whole breaking device 18 is inserted into the tubular body 15 from its open end,
Closing member 1 by uniformly tightening all stopper bolts 23
Fix 9 Then, the gas introducing pipe 26 is pushed to some extent to separate the closing plate 21 from the seal bag body 27, and when inflation gas is fed from the base end side of the gas introducing pipe 26, the seal bag body 27 is inflated and the pipe body 15 The inside will be blocked.

As a result, the combustible gas 17 in the pipe body 15 is
Is first blocked by the inflated seal bag 27. Further, even if a slight leak gas R is generated from the seal bag 27 for some reason, the leak gas R is blocked by the first seal means B without leakage and is released to the outside through the leak gas exhaust pipe 28. Be done.

In particular, the seal bag 27 is deformed according to the shape of the inner wall of the tube 15 and presses it, and the friction resistance generated thereby holds the gas introduction tube 26 in place without supporting it. Further, even if the friction resistance cannot withstand the internal pressure of the flammable gas 17 and the seal bag 27 is pushed, it is restricted by hitting the closing plate 21 fixed by the stopper bolt 23, so that it is pushed out of the pipe body 15. There is no such thing. Therefore, after inflating the seal bag 27, the work can be performed without supporting the gas introduction pipe 26.

Further, since the space between the seal bag 27 and the closing member 19 has the same atmospheric pressure as the outside due to the leak gas exhaust pipe 28, the leak gas R passes through the first seal member 24 and the seal member 25a. There is no leakage to the outside.

Next, a modified embodiment will be described.

As shown in FIG. 2, in this embodiment, the closing plate 21 of the closing member 19 which is the first sealing means B is
The gas introduction pipe 26 is slidably and airtightly penetrates. A packing member 30 made of an O-ring is provided in the through hole 21 a of the closing plate 21. The leak gas exhaust pipe 28 is connected to an exhaust means 31 installed outside. This exhaust means 31 is specifically a blower 32,
As a result, the inside of the tubular portion 20 is slightly sucked and the leak gas R
Is designed to be exhausted. As a result, the leak gas R leaking from the seal bag 27 is blocked before the closing plate 21, and even if it passes through the through hole 21a, it is completely sucked by the exhaust means 31. Thus, the shutoff device 18
By configuring the above, the gas blocking performance can be further improved. On the contrary, the blower 32 sends air to the cylinder 2
The inside of 0 may be slightly pressurized so that the leak gas R does not easily leak from the through hole 21a.

As described above, the shut-off device 18 has a double shut-off structure and an exhaust structure, so that the combustible gas 17 in the pipe body 15 is transferred to the work area A. It is possible to surely and completely shut off before this without leaking. Therefore, it is possible to safely perform a fire work such as welding in the work area A.

In the present embodiment, the gas introduction pipe 26
Although it is slidable, it may be fixed completely. Further, even if the gas introducing pipe 26 is provided with a piston (not shown) that slides in the tubular portion 20, the gas blocking performance can be improved.

[0027]

The present invention exhibits the following excellent effects.

(1) Combustible gas and the like in the tube can be reliably and completely shut off before the work area, and the fire work such as welding can be performed safely.

(2) In addition to the double blocking structure by the first sealing means and the second sealing means, since it has the exhaust structure by the leak gas exhaust pipe, the gas blocking performance can be further improved.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a gas shutoff device according to the present invention.

FIG. 2 is a side sectional view showing a modified example.

FIG. 3 is a side sectional view showing a conventional example.

FIG. 4 is a side sectional view showing a conventional example.

[Explanation of symbols]

 15 Pipe 17 Gas 18 Breaker 26 Gas Inlet 27 Seal Bag 28 Leak Gas Exhaust Pipe A Working Area B First Seal Means C Second Seal Means R Leak Gas

Claims (1)

[Claims] 1. A device for shutting off gas in the pipe body in the insertion direction forward of the working area of the pipe body where the pipe body is inserted from its open end to perform welding or the like, and is inserted into the pipe body from the open end. And a first sealing means that is located in front of the tubular body working area and is detachably attached to the inner wall of the tubular body and that shuts off the inside of the tubular body; A second sealing means, which is a sealing bag body that expands by the introduction and shuts off the inside of the tube, and a gas is introduced into the second sealing means, and the second sealing means is located forward of the first sealing means in the tube. A gas introduction pipe for positioning and supporting, and a leak gas exhaust pipe provided in the first sealing means for exhausting a gas leaking between the second sealing means and the first sealing means to the outside of the tubular body. Is equipped with A gas shutoff device for the pipe.