JP2001235087A - Gas interrupting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas interrupting device provided with a constitution capable of surely interrupting gas, by surely performing atmospheric release of passing gas also confirming an inflow of passing gas in a work interval in addition preventing a bag introduced into a pipe line from being carried away and tumbled. SOLUTION: This gas interrupting device, using a bag introduced into a pipe line buried in the ground to be made in close adhesion by expansion to an inner surface of this pipe line to interrupt circulation of gas, is characterized by a constitution comprising a first/second bag 3, 4 arranged before/behind a flow direction of gas in the above pipe line to be swell contractible, an insertion pipe 4D provided with a supply part 4E1 of gas for expansion to these first/second bags 3, 4 by respectively integrally forming the above first/second bags 3, 4 and a gas collection part 4C collecting gas from a gas take in part 4D1 formed in this bag, and a bag receiving means 5 formed with a space in the inside capable of inserting the above insertion pipe 4D to be respectively provided with an atmospheric release port 5C communicating with the inside of the space and support parts 5A, 5B of this insertion pipe.

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 shutting off a pipe to shut off gas flowing through the pipe, and more particularly to a gas shut-off apparatus for shutting off a pipe by a bag introduced into the pipe. Related to the structure.

[0002]

2. Description of the Related Art City gas produced at a gas generation plant is:
It is supplied to customers via large-diameter high-pressure lines, medium-diameter medium-pressure lines, small-diameter low-pressure lines and supply pipes. In recent years, pipeline maintenance for each line has been carried out in preparation for disasters such as large earthquakes. When such pipeline maintenance is performed, usually, after replacing the gas supply in the maintenance target section, replacement of the pipeline, repair of the pipeline, and the like are performed. Conventionally, when gas supply in an existing pipeline is cut off, a method of inserting an airbag into the pipeline and inflating the airbag is known as an example.

Conventionally, when an airbag is inflated to block gas flowing in a pipe, slugs and the like are present on the inner wall of the pipe, and if there is unevenness on the inner surface of the pipe, the outer surface of the airbag may be disturbed. Adhesion with the inner surface of the pipeline may become unstable. For this reason, it may be difficult to reliably shut off the gas, and when the close contact state is incomplete, there is a problem of generation of so-called overgas, which flows past the airbag.
Therefore, conventionally, as a countermeasure against overgas, a double airbag structure in which airbags are arranged in front and rear is used to diffuse the overgas that has entered between the airbags to the atmosphere.

[0004]

However, when the overgas is released to the atmosphere, it is necessary to check whether all the overgas is released to the atmosphere and the flow of gas into the construction section is completely cut off. It is not at present. In addition, there is no structure for replacement with an inert gas performed after the gas is cut off. Therefore, the replacement with the inert gas depends on the experience of the worker at present. Further, as a problem in the airbag shutoff structure, when introducing the airbag into the pipe, the pressure of the gas flowing through the pipe may cause the airbag to flow or fall.

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the conventional gas shut-off device, particularly in a device using a pipe line shut-off structure using a bag, it is an object of the present invention to ensure that exhaust gas can be released to the atmosphere, and that the gas can be transferred to a construction section. The gas shut-off device is provided with a configuration that can reliably check the gas without allowing the bag introduced into the pipeline to flow or fall down. To provide.

[0006]

In order to achieve this object, the invention according to claim 1 is introduced into a pipeline buried in the ground and is expanded and closely attached to the inner surface of the pipeline. In a gas shut-off device using a bag for shutting off gas flow, the first and second bags, which are arranged in front and rear of the gas flow direction in the pipe and are expandable and contractable, include the first and second bags. An insertion pipe integrated with a supply section for supplying inflation gas to the first and second bags and a gas recovery section for recovering gas from a gas intake section formed in the bags; A space through which the pipe can be inserted is formed inside, and is provided with an air vent opening communicating with the inside and a bag accommodating means provided with a support portion for the insertion pipe.

The invention according to claim 2 is characterized in that the internal space of the bag storage means communicates between the positions where the first and second bags are arranged.

According to a third aspect of the present invention, the supporting portion of the insertion tube is provided with a support piece provided to be capable of falling in the internal space of the bag housing means, and a lid for covering an upper end of the internal space of the bag housing means. And the insertion tube is inserted and supported outside the conduit.

The invention according to claim 4 is characterized in that the insertion tube has a polygonal cross-sectional shape, and is configured to be able to confirm the direction when the insertion tube is inserted and supported by the support piece.

[0010]

According to the first and second aspects of the present invention, the bag accommodating means is provided with an internal space communicating between the first and second bags, and an air vent communicating with this space. When the overgas flowing between the first bag located in the front direction and the inner surface of the pipeline reaches the position between the bags, the gas can be released to the atmosphere through the air outlet. Moreover, since the second bag located on the construction section side is provided with a gas intake port like the first bag, if the back pressure on the construction section side is detected via the insertion pipe,
The presence or absence of gas inflow into the construction section can be confirmed. further,
When the construction section is replaced with the inert gas, the inert gas can be supplied using the gas intake port on the second bag side, so that the replacement work can be reliably performed on the construction section. .

In the third and fourth aspects of the present invention, the polygonal insertion tube is inserted and supported by the support piece provided in the bag housing means, so that the polygonal shape matches the shape of the support piece. By doing so, it can be inserted and supported. Accordingly, when the facing shapes on the insertion tube side and the support piece side do not match, it can be determined that the orientation of the bag integrated with the insertion tube is not appropriate. In addition, since the support portion of the insertion tube supports the insertion tube at two places outside the channel, it prevents the bag integrated with the insertion tube from moving in the direction of falling or flowing due to the pressure of gas. it can.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration of a gas shut-off device according to an embodiment of the present invention.
Is a pipe having a large diameter of 400 mm or more (hereinafter, referred to as a pipe).
The first bag 3 and the second bag 4 are connected to the communication hole 2A formed in the communication hole 2 and are introduced from the inside of the communication hole 2A to block gas inflow, and these bags are introduced into the communication hole 2A. And a base plate 6 for installing the bag storage box 5 on the pipeline side.

The first bag 3 and the second bag 4 are respectively disposed on the front side and the rear side in the gas flow direction, one of which is shown in FIG. FIG. 3 is a view showing the second bag 4 located rearward in the gas flow direction in FIG. 1. In FIG. 3, the second bag 4 is a bag main body 4A.
And an insertion tube 4D integrated therewith. Note that, for the same configuration in the first bag 3 as well, the alphabet attached to the reference numeral “3” is indicated by the same letter. The bag body 4A is formed of a bag made of an expandable and contractible rubberized nylon base cloth. Although not shown, an inflatable holding structure is provided in the bag body 4A using a suspension band stretched between the front and back surfaces of the bag body 4A along the conduit laying direction. For example, as shown in FIG. 2, the hanging band is stretched around the bag body 4A in a circumferential direction so as to form a polygon and is integrated with the front and back surfaces. It is stretched over. The suspension band in the present embodiment forms a polygon having a similar shape, and forms a double suspension structure in which the vertexes of each polygon are stretched between the front surface and the back surface.

The bag body 4A is provided with a deformation margin 4B on the outer periphery thereof, and the center portion is formed as a recess 4C forming a passage passing through the front side to form a gas intake portion. . In the peripheral portion of the recess 4C, gas introduction ports 4A1, which are supply portions of the inflation gas, are communicated with a gas introduction pipe 4E inserted into the introduction pipe 4D at two locations on the diameter of the bag body 4A. . The deformation allowance portion 4B is a portion that can change its width in a state different from the width of the bag body 4A by expanding with respect to the width of the bag body 4A.
For this reason, as shown in FIG. 3, the deformable portion 4 </ b> B receives the shoulder 4 </ b> B 1 and the outer surface 4 </ b> B <b> 2 from the front and back surfaces of the bag body 4 </ b> A by the pressure of the inflation gas supplied into the bag body 4 </ b> A. And a case where the trapezoidal shape is collapsed and the bag body 4A is formed into a tire shape can be selected. That is, when the pressure in the bag body 4A is the maximum, the deformation margin 4B extends in the radial direction, and the shape of the entire bag becomes a tire shape. When the pressure in the bag body 4A is lower than the maximum value, , The deformation margin 4B according to the pressure difference
Approaches a trapezoidal shape. Thereby, when the deformation margin 4B has a trapezoidal shape, the width of the outer peripheral portion (indicated by L1 for convenience) is larger than the width of the bag main body 4A (indicated by L for convenience). The width is approximately equal to the width of the bag body 4A, and the outer diameter of the entire bag is increased.

In the deformation allowance portion 4B, the deformation amount in the radial direction is set so as not to be smaller than the width of the bag body 4A particularly in the case of the tire shape between the trapezoidal shape and the tire shape. This ensures a minimum necessary contact area for close contact with the inner surface of the conduit at maximum expansion. The contact area in this case is
The frictional resistance is such that the first and second bags 3 and 4 do not fall down in the conduit 2 and the outer peripheral surface 4B2 of the deformation margin 4B and the conduit 2
And the area generated between the inner surface and the inner surface. Accordingly, even if the width of the bag body 2A is reduced in design, the bags 3 and 4 do not fall due to the frictional resistance at the deformation margin 4B, that is, the inclination along the laying direction of the conduit 2 does not occur. The state in which the outer peripheral surface 4B2 of the deformation allowance 4B is in close contact with the inner surface of the conduit 2 can be maintained.

In FIG. 1, the insertion tubes 3D, 4D are formed in a polygonal shape such as a hexagonal outer diameter. The insertion pipes 3D and 4D communicate with the recess 4C through an opening 4D1 formed facing the recess 4C of the bag body 4A, and the gas introduction pipe 4E located in the insertion pipe 4D is connected to the bag body 4A. Communicates with the inside of the bag 4A via an opening 4E1 formed opposite the gas inlet 4A1. By integrating the recess 4C of the bag body 4A and the gas inlet 4A1 with the openings 4D1 and 4E1, the bag body 4A and the insertion tube 4D in a contracted state are configured in a flag shape, and the insertion tube 4D is formed. Corresponds to a pole, and the bag body 4A corresponds to a flag. As shown in FIG. 3, a support cone 10 having a shape that can slightly bite into the inner surface of the conduit 2 is integrated with the distal end of the insertion tube 4D, that is, the end on the side inserted into the conduit 2. And the movement of the bag can be prevented.

In the first and second bags 3 and 4 having the above-described structure, in FIG. 3, an inert gas such as carbon dioxide is introduced into the bag body 4A from the gas introduction pipe 4E through the opening 4E1. Depending on the pressure of the gas which expands and is introduced into the inside, the case where the outer peripheral surfaces 3B and 4B form a trapezoidal shape or a case where the outer peripheral surfaces 3B and 4B form a tire shape is selected. Further, when the gas is released from the inside of the bag body 4A, the bag can be contracted and folded. In this embodiment, although not shown, a hook is provided at a position facing the front and back sides that are folded and overlapped as a closed part in a folded state.

When the gas is introduced, the bag body 4A tends to expand in the width direction. However, since the expansion in the width direction is suppressed by the hanging band, the bag body 4A is easily expanded in the radial direction. .

The bag storage box 5 has a tubular shape, and has an insertion tube (indicated by a reference numeral 3D for the first bag) 4D in which the first and second bags 3 and 4 are integrated. A support member 5A for insertion and support is provided, and a lid 5B having holes for inserting and supporting the insertion tubes 3D and 4D is detachably provided at the upper end. Further, the bag housing box 5 is provided with an elbow 5C as an air vent that communicates with the inside between the lower end and the upper end, and recovers the overflow gas that has entered between the first and second bags 3 and 4. It can be released to the atmosphere.

The support member 5A is composed of a support piece provided to be able to be turned upside down, and has a support hole through which the insertion tubes 3D and 4D are inserted. Although not shown, the support hole has a shape corresponding to a part of a hexagon which is an outer shape of the insertion tubes 3D and 4D. When the support holes are folded down, the support holes are partially inserted into the outer peripheral surfaces of the insertion tubes 3D and 4D. The tubes 3D, 4D can be prevented from rotating, and the insertion tubes 3D, 4D
You can check the direction of the integrated bag.

The insertion pipes 3D, 4D have a bag body 3A,
Plug portions 7, 7 'communicating with recesses formed in the center of 4A are provided, and gas introduction pipes 3E, 4E are provided with:
Plug portions 8, 8 'communicating with the gas inlets 3E1, 4E1 (see FIG. 3) are provided. Among the plugs, the plugs 7, 7 'communicating with the insertion tubes 3D, 4D can detect the pressure of the gas in the conduit 2, and among them,
On the insertion tube 4D side located behind the gas flow direction, an inert gas can be supplied instead of pressure detection. The supply of the inert gas is performed from the concave portion 4C of the insertion pipe 4D located on the construction section side toward the construction section, and is performed for so-called gas replacement work in the construction section. Further, when the pressure on the front side in the gas flow direction is low,
Gas can be supplied and supplied from another system gas conduit or CNG gas cylinder to maintain a stable pressure.

The bag storage box 5 is mounted and fixed on the upper surface of a base plate 6, and the base plate 6 is formed on itself by a binding member 9 such as a chain as shown in FIG. The opening is positioned so as to face the opening 2A of the conduit 2 and then fixed. The base plate 6 is provided with a slidable shutter member 6A, which is closed until the first and second bags 3, 4 are inserted to prevent gas from leaking from the inside of the conduit 2. ing.

Since the present embodiment has the above configuration,
After the base plate 6 is mounted facing the opening 2A of the conduit 2 and the bag storage box 5 is placed on the base plate 6, the first and second bags 3, 4 are inserted into the conduit 2. can do. The first and second bags 3 and 4 include a bag storage box 5
The bag bodies 3A and 4A are positioned in the conduit 2 while being guided through the lid 5B and the support member 5A. Conduit 2
The first and second bags 3 and 4 arranged inside are held at the insertion position by the support cone 10 located at the tip of the insertion tubes 3D and 4D. When an inert gas is introduced into the bag bodies 3A and 4A of the first and second bags 3 and 4 via the gas introduction pipe 4E (see FIG. 2), the bag bodies 3A and 4A expand.

The amount of inflation is set by the pressure in the back bodies 3A, 4A, and the amount of inflation in the radial direction is set. In this embodiment, in addition to the inflation of the bag bodies 3A, 4A, deformation occurs. The conduit 2 depends on the amount of deformation at the
The state of close contact with the inner surface can be changed. In other words, the outer diameter dimension which affects the overall shape of the first and second bags 3 and 4 increases in accordance with the pressure increase in the bag bodies 3A and 4A, whereby the shape of the deformable portions 3B and 4B becomes trapezoidal. From the tire shape. Therefore, in the case of a tire shape, the outer peripheral surface 4 at the deformation allowance portions 3B, 4B
Since the width of B2 (refer to FIG. 3) is set to a width that can ensure the frictional resistance between the outer peripheral surface 4B1 and the inner surface of the conduit 2, even if the width of the bag bodies 3A, 4A is small, the width of the conduit 2 is small. No slippage occurs between the inner surface and the outer peripheral surfaces of the deformation margins 3B, 4B. As a result, the so-called overgassing is generated without the bag bodies 3A and 4A being inadvertently tilting due to the pressure of the gas flowing in the conduit 2, maintaining the close contact between the two and exceeding the outer peripheral surface. Can be prevented.

When the insertion tubes 3D, 4D are inserted into the bag housing box 5, the support members 5A are raised, and when inserted, the support members 5A fall down. Thereby, the insertion tube 3
When the support member 5A is inserted through the insertion tube 3D,
The direction of the bag integrated with the insertion tubes 3D and 4D can be confirmed by obstructing the insertion passage of the insertion tubes 3D and 4D without interfering with the insertion passage of the 4D. Thereby, the orientation of the bag is optimized, and the concave portions 3C and 4C, which are the gas intake portions on the bag side, can be directly opposed to the gas flow. When the cover 5B is covered,
By opening the cock 5D provided in the bag storage box 5, the pressure inside the internal space is prevented from rising, and the upper end opening of the bag storage box 5 can be quickly closed by the lid 5B. The cock 5D can also be used to detect the pressure of the overflow gas that enters the bag housing box 5 with the air vent 5C closed.

In the second bag 4 located on the construction section side,
By detecting the pressure on the construction section side by the concave portion 4C, it can be confirmed whether or not the overgas has entered the construction section.
In addition, when the overgas enters the construction section, the gas is replaced in the construction section. In this case, the plug on the side of the insertion pipe 4D communicating with the recess 4C is required. 7 is connected to a supply source of an inert gas, and the inert gas from this supply source is introduced into the construction section side from the concave portion 4C, thereby performing gas replacement in the construction section.

On the other hand, the first and second bags 3 and 4 in close contact with the inner surface of the conduit 2 in the conduit 2 have the insertion pipes 3D and 4D in two places with the support member 5 and the rear lid 5B in the bag storage box 5. Since it is supported, it is possible to prevent the first and second bags 3 and 4 from flowing or falling due to the pressure of the gas. Therefore, by arranging the insertion tubes 3D and 4D in a state perpendicular to the gas flow, the outer peripheral surfaces of the first and second bags 3 and 4 can be most efficiently adhered to the inner surface of the conduit 2, The gas in the conduit 2 can be sealed most efficiently.

[0028]

According to the first and second aspects of the present invention,
Since the bag housing means has an internal space communicating between the first and second bag arrangement positions and an air vent opening communicating with this space, the first bag located in front of the gas flow direction and the pipe inner surface When the overflow gas flowing between them reaches the position between the bags, it can be released to the atmosphere via the air outlet. Moreover, the second bag located on the construction section side
Since the gas intake port is provided similarly to the first bag, if the back pressure on the construction section side is detected via the insertion pipe, it is possible to confirm whether or not gas has flowed into the construction section. This makes it possible to prevent an accident at the start of construction. Further, when replacing the gas to deactivate the inside of the construction section, the inert gas can be supplied using the gas intake port on the second bag side, so that no special replacement structure is used. This can be performed by also using the shut-off structure, so that an increase in equipment cost can be suppressed.

According to the third and fourth aspects of the present invention, the polygonal insertion tube is inserted and supported by the support piece provided in the bag housing means, so that the polygonal shape and the shape of the support side are changed. By matching, it can be inserted and supported. Accordingly, when the facing shapes on the insertion tube side and the support piece side do not match, it can be determined that the orientation of the bag integrated with the insertion tube is not appropriate. In addition, since the support portion of the insertion tube supports the insertion tube at two places outside the channel, it prevents the bag integrated with the insertion tube from moving in the direction of falling or flowing due to the pressure of gas. it can. This makes it possible to optimize the state of close contact between the bag and the inner surface of the pipeline and more reliably prevent the generation of overgas.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an overall configuration of a gas cutoff device according to an embodiment of the present invention.

FIG. 2 is a view showing a state in which the gas shut-off device shown in FIG. 1 is mounted on a pipeline.

FIG. 3 is a view for explaining a configuration of a bag used in the gas shut-off device shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas shut-off device 2 Conduit forming conduit 3 First bag 3A Bag main body 3B Deformation margin 3C Depression corresponding to gas intake part 4 Second bag 4A Bag main body 4B Deformation margin 4C Depression equivalent to gas intake part 4D Insertion Pipe 4E Gas introduction pipe 5 Bag storage box corresponding to bag storage means 5A Support member which is one of the support parts 5B Lid which is another one of the support parts 5C Air vent 6 Base plate

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nori Morita 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) Inventor Akihito Mouri 2-chome Nakaike-kami, Ota-ku, Tokyo No. 6 O-Kag Precision Co., Ltd. F-term (reference) 3H025 DA02 DB18 DC02

Claims (4)

[Claims] 1. A gas shut-off device using a bag which is introduced into a pipe buried underground and is inflated so as to be in close contact with the inner surface of the pipe to block gas flow. The first and second bags, which are arranged in front of and behind the flow direction of the gas and are inflatable, are integrated with the first and second bags, respectively.
An insertion pipe including a supply section for supplying inflation gas to the second bag and a gas recovery section for recovering gas from a gas intake section formed in the bag; and a space through which the insertion pipe can be inserted is provided inside. A gas shut-off device, comprising: an air vent that is formed and communicates with the inside thereof; and a bag accommodating unit that is provided with a support portion for the insertion tube. 2. The gas shut-off device according to claim 1, wherein the internal space of the bag accommodating means communicates between the positions where the first and second bags are arranged. 3. The support portion of the insertion tube includes a support piece provided so as to be capable of being turned up and down in the internal space of the bag housing means, and a lid for covering an upper end of the internal space of the bag housing means. The gas shut-off device according to claim 1, wherein the insertion tube is inserted and supported outside. 4. The insertion tube has a polygonal cross section,
4. The gas shut-off device according to claim 3, wherein an orientation of the gas shut-off device when inserted and supported by the support piece can be confirmed.