JP2000055287A - Interrupting method for gas main and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly, surely, and safely interrupt gas in the adjacent to a leakage point by entering an exit/entrance of a gas bag charged and installed beforehand in a drilling device after drilling a hole in the upper area of the gas main interrupting position into the gas main under such a state as holding an airtight state and by feeding the gas bag therein. SOLUTION: After completing the drilling by the rotation of a shaft 7b of a drilling device 7 which is anchored and fixed to an upper area of a gas main exposed from the ground by a fitting fixing part 4, the drilling tool 7a is inserted into a position reaching the bottom of the gas main, an exit/entrance 14 formed in the bottom of the shaft 7b is entered in the gas main, and a connecting part 10 of the gas bag 8 is exposed to the outside. After that, the gas bag 8 is fed from the exit/entrance part 14 to the gas main by thrusting of the feed pipe connected to the connecting part 10 and gas (inert gas) is pressurized in the gas bag 8 through the feed pipe to inflate the gas bag 8, thereby interrupting the gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for shutting off a gas main pipe, especially when urgency is required such as when air leaks from an underground city gas main pipe (low pressure pipe). The present invention relates to a blocking method and a device useful for applying the method.

[0002]

2. Description of the Related Art As a measure to be taken when a leak from a gas main which requires an emergency shutoff is considered, it is conceivable to close a valve provided in the gas main. However, in such a method, a customer who receives supply of city gas from the main pipe between the valves is in a gas-cut state, and causes trouble to a large number of customers (usually estimated to be several thousands to tens of thousands).

[0003] Further, it is conceivable to apply a shutoff by a gas bag employed in ordinary gas construction or the like. According to this method, gas can be shut off by inserting and inflating the gas bag into the gas main pipe through the perforated portion formed in the gas main pipe in the vicinity of the leak location, thereby minimizing inconvenience to consumers. Range. However, in gas construction, it usually takes several hours to shut off gas, and the purpose of emergency shutoff cannot be achieved with this. In addition, there is a problem in terms of work safety, for example, gas is leaked when the gas bag is inserted into the gas main pipe, and it is necessary to wear a gas mask.

[0004]

SUMMARY OF THE INVENTION The present applicant previously disclosed in Japanese Patent Publication No. 1-28277, using a supply lamp outer tube extending from a city gas main to a customer. An emergency shut-off method in which the lamp outer tube is removed at the location of the gas meter installed in the customer to form a working port, and a gas bag is inserted from the working port through the lamp outer tube into the gas main pipe, and then inflated to shut off the gas by inflating. Proposed. According to this method, the time required for shutting off the gas can be shortened and the safety of work can be satisfied. However, the outer lamp of the supply lamp often has a bent portion in the middle, and the When inserting the gas bag with the guide of the wire, the bag may be supported by the bent portion of the pipe and cannot pass therethrough.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shut-off method and a device for shutting off gas quickly, reliably and safely in the vicinity of a leak location.

[0006]

According to the present invention, a piercing device having a shaft portion and a piercing tool at the lower end of the shaft portion is applied to an upper region of a shut-off position of a gas main pipe to perform piercing in a gas-tightly maintained state. After that, the lower part of the perforation device is inserted into the gas main pipe while keeping the airtight state, the entrance of the gas bag provided at the lower part of the shaft portion is advanced into the gas main pipe, and the perforated device is inserted into the shaft portion of the perforation device. The gas bag previously charged and installed in a state of being cut off from the outside air is sent into the gas main line through the above-mentioned entrance and exit under the external operation, and thereafter, the gas bag is inflated by the external operation and the gas is shut off. The present invention relates to a gas mains shutoff method.

Further, the present invention comprises a mounting portion for mounting on the upper region of the gas main pipe, a tubular portion which stands up from a center portion of the mounting portion and penetrates the mounting portion, and a mounting and fixing provided on the bottom surface of the mounting portion. A base that can be fixedly set in the upper region of the gas main pipe while maintaining a tight seal between the upper region and the upper region, and slides in the vertical direction and around the axis in the tubular portion of the base at the shaft portion. The gas main pipe can be pierced by a piercing tool provided at the lower end of the shaft part, and after piercing, the lower part of the shaft part can be inserted into the gas main pipe and the lower part of the shaft part has the following gas bag. A perforation device provided with an entrance, and c, which is previously inserted and installed in a shaft portion of the perforation device in a state of being shielded from the outside air, and is externally operated to enter and exit the gas main from the entrance and to be sent into the gas main. Inflated position Possible gas bag, according to the cut-off device for a gas mains, characterized in that it comprises a city.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings. Figures 1 and 2
Represents the entire apparatus to be adapted to the practice of the present invention interrupt method, the apparatus includes a fixed of possible base 1 mounted in an upper region a ₁ in gas mains a.

The base 1 includes a mounting portion 2 for mounting the gas main pipe a in the upper region a ₁ , and a tubular portion 3 that stands up from the center of the mounting portion 2 and passes through the mounting portion 2. Bottom 2a of the mounting portion 2 is preferably curved in the front arc-shaped (see FIG. 2) with a curvature which substantially coincides with the upper region a ₁ in order to extend along the upper region a ₁ in gas mains a.

A gas main pipe a is provided on the bottom surface 2a of the mounting portion 2.
Attaching the fixing portion 4 to the upper region a ₁ fixing airtightly fixed to the is provided.

FIGS. 1 and 2 show a type having a vacuum suction mechanism as a mounting and fixing part 4. A pair of inner and outer parts are formed on the bottom surface 2 a of the mounting part 2 so as to be substantially concentric with the tubular part 3. sealing ring 4a, 4b are mounted at intervals between each other, the seal ring 4a, and 4b in a state of being in close contact with the upper region a _1, the ring 4a, the inside cavity 5 between 4b By applying a vacuum by applying a vacuum generator (not shown) through the suction hole 6 to create a vacuum, the upper region a ₁
It can be fixed by suction. Sealing ring 4a, with crimped to the upper region a ₁ side of 4b, the seal is subjected to prevent gas leakage around the lower end opening of the tubular section 3. The seal rings 4a, 4b are formed of an elastic material, for example, rubber.

As the mounting and fixing portion 4, a suction mechanism using a magnet may be employed instead of the vacuum suction mechanism. In this case, the inner and outer seal rings 4a, 4b in the vacuum suction mechanism
One of them may be replaced with a magnet. In the case of attraction by a magnet, it is sufficient to arrange the magnet block pieces at intervals, and the remaining seal ring 4a (or 4
Airtightness is obtained by the sealing function of b). In addition, a plurality of magnets may be provided on the back surface of the installation part 2 in parallel in the tube axis direction, or a plurality of magnets may be provided in an arc shape and parallel in the direction around the tube. In addition, it may be configured to apply an adhesive fixing means of applying an adhesive material,
In this case, in order to provide a sealing function, the adhesive layer needs to be formed continuously so as to surround the lower end opening of the tubular portion 3. The adhesive layer is protected by a release paper until use. The adhesive layer can be of a replaceable type.

A drilling device 7 is freely inserted into the tubular portion 3 of the base 1 below the shaft portion 7b, and is rubbed by a bearing 12 provided on the inner peripheral portion at the upper end of the tubular portion 3. The bearing 12 is configured to be freely slidable up and down and around the axis. Bearing 12
Is made of, for example, metal, and the sliding portion forms a seal for preventing gas leakage. The bearing 12 may be provided with a sealing device, such as an O-ring (not shown), to further ensure the seal of the sliding portion.

The piercing device 7 is provided with a piercing tool 7a (for example, a hole saw) at a lower end, and is configured to be capable of piercing the gas main pipe a by rotation. In order to prevent the drilling device 7 from coming off from the base 1, the drilling tool 7 a is slightly larger in diameter than the shaft portion 7 b and has a large diameter portion 3 at the lower end of the through hole of the tubular portion 3.
a.

The shaft portion 7b of the drilling device 7 is hollow and has a hollow portion 7
The gas bag 8 is housed under the bar-shaped reduced state in c.

The gas bag 8 is provided at its upper end with a connecting portion 10 for connecting to an air supply pipe 9 (see FIG. 1). The connecting portion 10 slides through a through hole 11a of a plug portion 11 which closes an upper end opening of the shaft portion 7b. It passes under the matching condition and protrudes outward. The portion of the through hole 11a that is rubbed with the connecting portion 10 constitutes a seal for preventing gas leakage, and an O-ring (not shown) or the like is provided in the through hole 11a of the plug 11 for the purpose of improving the sealing performance. A simple sealing device.

The connecting portion 10 and the air supply pipe 9 can be coaxially connected by applying an appropriate joint means having the same outer diameter, and after the connection, the air supply pipe 9 is connected to the through hole 11a of the plug portion 11. Can be passed under the rubbing state without any trouble.

An inlet / outlet 14 for the gas bag 8 is formed at a lower side portion of the shaft portion 7b.
c is connected to the lower end side. The entrance 14 is provided with a chute-shaped guide portion 15 for changing the direction of the gas bag 8 from the vertical direction to the horizontal direction. The guide portion 15 closes the lower end of the hollow portion 7 c and forms the bottom of the entrance 14. are doing.

Various types of gas bags have already been proposed as the gas bag used for shutting off the gas main pipe a. These gas bags are
Normally, the rod-shaped reduced shape is maintained, and when the internal pressure is applied, it expands and shuts off the gas main pipe, and when the internal pressure is released, the original rod-shaped reduced shape can be automatically restored again. The parasol type described in JP-A-7-190284 is preferable because it has a frame and has excellent shape retention properties both when the rod is reduced and when it is expanded.

At the upper end of the shaft 7b of the drilling device 7, a drive socket 16 having a connection 16a to a drive device 13 (see FIG. 4) is fitted in a detented state.

3 to 7 show, in the order of steps, a situation in which the above-described apparatus is applied and the gas main is shut off in accordance with the method of the present invention.

According to the present invention, as shown in FIG. 3, first, the ground to be cut off is excavated, and the upper half of the gas main pipe a is exposed. In normal gas construction, it is necessary to expose the entire gas main pipe. However, in the present invention, it is sufficient to expose the upper half of the gas main pipe, and the time required for excavation can be shortened accordingly.

[0023] Next, the vacuum apparatus shown in FIG. 1 and 2, in the upper region a ₁ in gas mains a exposed from the ground at the installation section 2 of the base 1, with the bottom surface of the mounting portion 2 The fixing and fixing are performed by applying the mounting and fixing part 4 such as a suction method.

Next, as shown in FIG. 4, the drilling device 7 is connected to the driving device 13 via the drive socket 16 at the upper end of the shaft portion 7b, and the driving device 13 is operated to rotate. receive. As the shaft 7b rotates, the piercing tool 7a pierces the gas main pipe a, and when the piercing is completed, the shaft 7b is inserted into the gas main pipe a, for example, as shown in FIG.
a to the bottom of the gas main pipe a, the entrance 14 formed in the lower part of the shaft 7b is inserted into the gas main pipe a, the drive socket 16 and the driving device 13 are removed, and the gas bag 8 (FIG. 1) is exposed to the outside.

The operation from the drilling of the gas main pipe a to the insertion of the drilling device 7 into the gas main pipe a is performed between the installation part 2 and the gas main pipe a by the sealing function of the mounting and fixing part 4.
Further, between the shaft portion 7b of the punching device 7 and the tubular portion 3 and the plug 1
The connection between the connector 1 and the connecting portion 10 is temporarily blocked from the outside air by a mating fitting, so that the operation can be performed in a substantially gas-free state. The sealing performance of the sliding fitting portion can be further ensured by applying a sealing device such as an O-ring.

After the perforation apparatus 14 is inserted into the gas main pipe a by inserting the perforation apparatus 7 into the gas main pipe a, the air supply pipe 9 is connected to the connection portion 10 of the gas bag 8 as shown in FIG. And the gas bag 8 is inserted into the entrance 1 by pushing the air supply pipe 9.
Then, the gas is sent into the gas main pipe a through the gas supply pipe 4, and thereafter, a gas, for example, an inert gas (for example, nitrogen gas) is injected into the gas bag 8 through the air supply pipe 9 to expand the bag 8, thereby shutting off the gas. I can do it.

The operation of feeding and inflating the gas bag 8 from the perforation of the gas main pipe a into the gas main pipe a can be performed by a substantially continuous operation without the necessity of changing the setup. It is possible to shut off the gas main pipe a in several tens of minutes.

After the gas shut-off is no longer necessary, the gas bag 8 is released from the internal pressure and contracted, and then the air supply pipe 9 is pulled from the inlet / outlet 14 to the hollow portion 7c of the shaft portion 7b.
Into the tubular portion 3 together with the piercing tool 7a at the lower end of the shaft portion 7b of the piercing device 7, and thereafter,
The shut-off operation is completed by making the installation part 2 free from the gas main pipe a. Incidentally, the perforated portion of the gas main pipe a can be restored by applying restoration means similar to ordinary gas construction, for example, plugging means with a plug.

As shown in FIG. 7, by providing two devices of the present invention in parallel, gas can be shut off at two places on the left and right sides of the device. In this case, the mounting part 2 of the base 1
The mounting and fixing part 4 can be shared.

[0030]

According to the shut-off method and apparatus of the present invention, it is possible to shut off the gas main pipe safely, quickly and reliably.

[Brief description of the drawings]

FIG. 1 is a longitudinal side view of a device applied to the blocking method of the present invention.

FIG. 2 is a partial longitudinal sectional view of the same as viewed from the front side.

FIG. 3 is a partial longitudinal sectional view showing a state where the above-mentioned device is fixedly fixed to an upper region of a gas main pipe.

FIG. 4 is a partial vertical sectional view showing a state of a punching operation.

FIG. 5 is a partial longitudinal sectional view showing a state in which a lower portion of a shaft portion of the drilling device is inserted into a gas main pipe after the drilling.

FIG. 6 is a partial longitudinal sectional view showing a state where a gas bag is sent into a gas main pipe.

FIG. 7 is a partial vertical cross-sectional view showing a state in which gas is blocked by inflating a gas bag.

FIG. 8 is a longitudinal sectional view showing an example of a double-type breaking device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Installation part 2a Bottom surface 3 Tubular part 4 Attachment fixing part 4a Inner seal ring 4b Outer seal ring 5 Void 6 Suction hole 7 Drilling device 7a Drilling tool 7b Shaft 7c Hollow 8 Gas bag 9 Air supply pipe 10 Connection DESCRIPTION OF SYMBOLS 11 Plug body 11a Through-hole 12 Bearing 13 Drive device 14 Doorway 15 Guide 16 Drive socket

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuo Miyazaki 2-16-6 Oimazato Minami, Higashinari-ku, Osaka, Osaka (72) Inventor Masaaki Obinata 3-3-20, Kikyogaoka Minami, Nabari-shi, Mie (72) Invention Person Jin Miura 1-7-36 Ieharaji-cho, Sakai-shi, Osaka Maison House Hara-ji 101 F-term (reference) 3H025 DA01 DB18 DC01 DD01

Claims (7)

[Claims] 1. A piercing device provided with a shaft and a piercing tool at the lower end of the shaft in the upper region of the shut-off position of the gas main pipe, and piercing is performed in a hermetically sealed state. The lower part is inserted into the gas main pipe while maintaining the airtight state, the entrance of the gas bag provided at the lower part of the shaft part is advanced into the gas main pipe, and the gas bag is previously mounted in the shaft part of the perforation device in a state of being shielded from outside air. The gas main, wherein the gas bag which has been installed is sent into the gas main through the above-mentioned entrance and exit under the external operation, and thereafter, the gas is inflated by external operation to perform gas shut-off. Blocking law. 2. A gas main unit comprising: a mounting portion for mounting on the upper region of the gas main pipe; and a tubular portion rising from a central portion of the mounting portion and penetrating the mounting portion, and a gas fixing portion provided on a bottom surface of the mounting portion. A base which can be fixedly set in an upper region of the tube while keeping the space between the upper region and the upper region airtight; (b) a shaft portion which is slidably inserted into the tubular portion of the base in a vertical and axial direction. The gas main pipe can be pierced by a piercing tool provided at the lower end of the shaft, and after the piercing, the lower part of the shaft can be inserted into the gas main pipe and the lower part of the shaft has the following gas bag inlet / outlet. A perforation device, and c at a position that is previously inserted and installed in a shaft portion of the perforation device in a state of being shielded from the outside air, and that enters and exits the gas main pipe from the entrance and exit and is sent into the gas main pipe by an external operation. Inflatable gas bag Breaker of the gas mains, characterized in that it comprises and. 3. The shut-off device according to claim 2, wherein a bottom surface of the mounting portion of the base is curved with a curvature substantially corresponding to an upper region of the gas main pipe. 4. The shut-off device according to claim 2, wherein the fixing portion provided on the bottom surface of the mounting portion of the base has a vacuum suction mechanism. 5. The shut-off device according to claim 2, wherein the mounting and fixing portion has a magnet attraction mechanism. 6. A guide for changing the direction of a gas bag at an entrance / exit.
6. The shut-off device according to any one of 5. 7. The shut-off device according to claim 2, wherein two of the shut-off devices are installed so as to share a mounting portion of the base.