JPH0128278B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an emergency shutoff method for gas mains, more specifically, a method for quickly shutting off gas mains (low pressure pipes) when air leaks from underground city gas mains (low pressure pipes). Concerning an emergency shutoff method for performing crab gas shutoff treatment.

Prior Art and its Problems When a leak from a gas main pipe that requires emergency shutoff is discovered, closing a valve provided in the gas main pipe may be considered as a countermeasure. However, with this method, customers who are supplied with city gas from the main pipe between the valves are cut off, causing inconvenience to a large number of customers (usually estimated to be several thousand to tens of thousands of people). Another possibility is to use a gas bag to shut off the gas, which is used in normal gas construction, but this method requires time to excavate the ground and drill holes in the main pipe (for inserting the gas bag). It takes several hours to shut off, and the purpose of emergency shutoff cannot be achieved.

The object of the present invention is to provide an emergency shutoff method that can shut off a gas main pipe as quickly as possible at a location as close to the leakage point as possible.

Means for Solving the Problems The present invention provides for removing the supply light pipe that extends from the city gas main pipe buried underground to the consumer at the gas meter installed at the consumer; While inverting and inserting the flexible rubber tube from the tube opening of the togai tube into the pipe by applying a tube reversal insertion means using fluid pressure, the flexible rubber tube is introduced into the gas main pipe connected to the togai tube, and into the gas main pipe. This invention relates to an emergency shutoff method for a gas main pipe, which is characterized by inflating the inverted insertion portion of the rubber tube that has been reached under the action of fluid pressure to shut off the inside of the main pipe.

Effects According to the present invention, the supply light tube is removed at the meter installed at the consumer, and the meter side pipe opening of the removed light bulb is used as a work opening, so that most of the work opening can be formed. It doesn't take much time. In addition, the length from the outlet of the supply light outer tube used as a work opening to the gas main pipe is approximately 5 to 7 mm at most, depending on the conditions at the construction site. Insertion of the flexible rubber tube into the main pipe also does not require much time. Therefore, it only takes about 10 minutes, or at most 20 to 30 minutes, from the start of work to shut off, and the time required to shut off the gas is significantly shortened compared to, for example, the several hours it takes to shut off the gas in gas construction. can.

Furthermore, since the gas main pipe can be shut off using the supply light pipe, the gas main can be shut off at a customer near the leak point, and the range of customers who would be inconvenienced by the gas outage can be isolated. It can be kept in a narrow range very close to the air.

Embodiment An embodiment of the present invention will be described below based on the accompanying drawings.

When carrying out the method of the present invention, the first step is to
After closing the iron pot 3a from the state shown in the figure, remove the upper light tube 2' above the pot 3a from the gas meter 3. This situation is shown in FIG. Next, as shown in FIGS. 3 to 5, the flexible rubber tube 4 is reversely inserted into the tube 2 from the tube opening 2a of the supply lamp outer tube 2 by applying a tube reverse insertion means using fluid pressure. During this reverse insertion operation, the iron cock 3 remains open.

The tube reversal insertion means itself that utilizes fluid pressure is applied to the reversal insertion of the flexible rubber tube 4.
BACKGROUND OF THE INVENTION Various inverted insertion means are known in the art and have already been developed, for example, for carrying out tube lining on the inner surface of a buried pipe. In the present invention, such various known reversal insertion means can be employed as they are. Examples of the fluid used for such reverse insertion of the tube include air and water, which may be used alone or in combination, and a combination of air and water is particularly preferred.

An example of this reversal insertion means will be explained based on FIGS. 3 to 5. First, as shown in FIG. Pull it out to the outside,
It is connected to the tube port 2a of the supply lamp tube 2, and also connects the inside of the pressure chamber 6 and the interior of the lamp tube 2 through an elastic conduit 8. In FIG. 3, reference numeral 9 denotes a connecting fitting having an H-shaped cross section and inserted into the pipe port 2a. Next, open the iron pot 3a from the state shown in FIG.
When the compressed air is supplied to the light tube 2 through the conduit 8, the tube 4 is reversely inserted into the light tube 2 by this compressed air supply, and this reverse insertion of the tube 4 advances inside the tube together with the compressed air. This state is shown in FIG. If the pressure of this compressed air is too high, there is a risk that the tube 4 will stretch unnecessarily within the tube or the tip of the inverted insertion section will bulge and burst. The operating pressure during insertion is preferably greater than the gas pressure within the tube and within a pressure range such that the tube does not begin to expand. When the tube 4 is reversely inserted, braking is normally applied to the feeding of the tube.

When the reverse insertion part 4a of the tube 4 reaches the inside of the gas main pipe 1, feeding of the tube 4 is stopped, and then the operating pressure is changed to such that the tube 4 starts expanding.
As shown in FIG. 5, the reverse insertion portion 4a of the tube 4 bulges within the gas main pipe 1, thereby achieving the purpose of shutting off the main pipe 1.

When the air leak has been repaired and there is no longer a need to shut it off, the system is returned to atmospheric pressure, the tube 4 is reeled back onto the reel 7, and the tube 4 is removed from the inside of the light tube 2.
, and then reconnecting the pipe port 2a of the light tube 2 and the gas meter through the upper light tube 2', the current situation can be immediately restored.

Effects In the present invention, a flexible rubber tube is reversely inserted into the gas main pipe from the supply light bulb and inflated to shut off the inside of the main pipe, so there is no need for complicated work such as excavating the ground or perforating the gas main pipe. This eliminates the need for any additional work, making it possible to achieve the purpose of emergency shutoff easily, quickly and reliably, and since the method uses a light tube, it is possible to shut off at a position close to the leakage point. Shutdown can be accomplished without causing any inconvenience to anyone other than the nearest customer, and both emergency shutoff performance and customer considerations can be satisfied.

Furthermore, if there is no longer a need for shutoff, the current situation can be immediately restored by releasing the pressure from inside the tube, pulling out the tube from the inside of the togai tube, and then connecting the togai tube to the gas meter again.
It has the characteristic that complete recovery can be achieved quickly and easily.

[Brief explanation of drawings]

The drawings show one implementation state of the present invention, and FIG.
Figure 2 is a vertical cross-sectional view showing the state in which the light tube has been removed from the gas meter, Figure 3 is a vertical cross-sectional view showing the state in which a flexible rubber tube is connected to the tube opening of the light tube, and Figure 4 is a vertical cross-sectional view showing the state in which the light tube is removed from the gas meter. FIG. 5 is a vertical cross-sectional view showing a state in which the flexible rubber tube is being reversely inserted into a pipe, and FIG. 5 is a vertical cross-sectional view showing a state in which the main pipe is blocked. In the figure, 1 is the gas main pipe, 2 is the supply light pipe, and 3 is the gas main pipe.
4 is a gas meter, 4 is a flexible rubber tube, and 5 is a tube reversal insertion device.

Claims (1)

[Claims] 1. Remove the supply light pipe that extends from the city gas main pipe buried underground to the consumer at the gas meter installed at the consumer, and flexibly insert the supply light pipe from the pipe opening of the supply light pipe into the pipe. applying a tube reversing and inserting means using fluid pressure to reversely insert the rubber tube into the gas main pipe connected to the light tube;
An emergency shutoff method for a gas main pipe, which is characterized by inflating the inverted insertion portion of the rubber tube that has entered the gas main pipe under the action of fluid pressure to shut off the inside of the main pipe.