JPS5986787A - Method of inserting stringy material in pipe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wiring method for pipes mainly buried underground, such as gas pipes and water pipes, and is particularly applicable to small-diameter pipes with many bends. It was made for the purpose of

In city gas piping, the supply gas conduit for supplying all the city gas to each household from a branch pipe buried in a public road or the like is a complicated pipe as shown in FIG. That is, the service pipe 21L is connected to the branch pipe 1, and the pipe branched from the service pipe 2a passes through the bend part J3a to the horizontal part 4.
af is formed, and further reaches the T-shaped tube portion 5 via the bend portion 8b. The pipe branching upward from the T-shaped pipe section 5 is connected to the service channel 2b through the rising section 9 (5a f), and the pipe branching downward is connected to the water intake tank 7. The pipe branching from the service channel 2b is again exposed on the ground at the rising part 6b through the bend part 3c, the horizontal part 4b, the pend part 811.:1lle'z, and is connected to a meter (not shown). In this case, as shown by the chain line in FIG.
Since eight 4-bi elbows are used to bend the pipe to avoid obstacles, the piping is extremely complicated with many bends.

By the way, since the above-mentioned supply waste conduit is used to convey city gas for use in a single household, it is generally of a small [J diameter, and usually has a nominal diameter of about 1 inch. This conduit has an inner diameter a of 27 I in the straight pipe section.
I, and the inner diameter hardly changes at the bend portion, as shown in FIG. However, elbow 8 and service chi 2. In the T-tube portion 5, the inner diameter 0 is enlarged as shown in FIGS.
It is about R.

Now, in general, as a method of completely inserting a string-like object into a pipe and running the wire, the tip of the string-like object is connected to a running body called a vig, and the pressure of fluid (usually air) is applied to the rear of the vig. A method is known and widely used in which the V-vig is caused to travel all the way through the pipe using the pressure, and the string-like object is drawn into the entire pipe and inserted.

However, this method is extremely difficult to apply to small-diameter pipes with many bends, such as the supply gas conduit mentioned above. This is because the diameter of the pipe is small, so the pressure-receiving area of the vig is small, and the force with which the vig pulls the string is small. Moreover, if there are many bends, the frictional resistance between the string-like object and the inner surface of the tube will be large, and it will take a force of 1 for insertion. Furthermore, the rate of variation in the pipe diameter is large relative to the pipe diameter, and the pig cannot follow the variation. Even if a tube with an inner diameter of 100 ff had a maximum diameter variation of 12π, the ratio would be only 12%, and the elasticity of the VIG would allow the light to follow the diameter variation.
As mentioned above, if a pipe with an inner diameter of only 27 inches has a maximum diameter variation of 8 inches, the ratio would reach 30 inches, and the shape of the big pipe would be impossible to follow. Therefore, if the big is thick, it can pass through the bend, and the more it can pass through the bend, the IW
If it is a small piggy, elbow, service chi, T'
A large amount of air leaks from between the vig and the inner surface of the pipe in the f-pipe section, etc., making it impossible to pump the pipe.

The present invention has been developed in view of the above circumstances, and involves intermittently generating rapid airflow within the tube, and inserting a string-like object into the tube as the traveling body travels through the tube due to the airflow.

FIG. 6 shows the state in which the string-like elongated object 10 is inserted and twisted into the supply gas conduit 9 by the method of the present invention. The meter mounting portion of the rising portion 6b of the conduit 9 is completely removed, and this is the end on the starting side of the entire traveling body. A starting fitting 11 is attached to the starting tube end, and an air feed pipe 12 and a pressure gauge 13 are attached to the starting fitting 11. Reference numeral 14 denotes a running body, to which the tip of a string-like object 10 is connected, and is inserted into the conduit 9 from the starting fitting 11. The running body 14 has the diameter of the smallest diameter part of the conduit 9! 7%, has a small head 15, and behind the head 15 is provided a non-expanding skirt 16 made of extremely flexible material, the diameter of the tip of the skirt 16 being 4 tubes. The diameter of the thickest part of the pipe in 9 is equal to y.

The upper end of the starting metal fitting 11 is a gasket 17. washer 1
8 and the cage 19, and the string-like object 10 is removed from the hole 20 of the packing 17 and washer 18,
The bottom is closed with a stopper 21 to prevent leakage of city gas from the branch pipe 1 and prevention of air inflow into the branch pipe 1. A transparent tube 24 is connected to the upper part of the service tee 2a via a reducer 22 and a fitting 23, and a valve 26 is further attached via a fitting 25. Further, a pressure gauge 27 is attached to the lower part of the valve 26.

Now, when compressed air is sent in from the air supply pipe 12, air pressure acts on the rear part of the traveling body 14, and this pressure causes the traveling body to move to f81. It is fed under pressure toward the end of the tube 9 on the reaching side. At the beginning of the pumping, the frictional resistance between the string-like material 10 and the inner surface of the conduit 9 is small, and the traveling body 14 runs entirely within the conduit 9 while pulling the string-like material 10. However, the traveling body 14 advances to a certain extent),
The resistance of the string-like object 10 increases, and it becomes impossible to proceed with air pressure alone. Furthermore, even if the air pressure is fully increased, it will not leak from between the traveling body 14 and the inner wall of the conduit 9, increasing the pressure difference between the front and rear of the traveling body 14, and the 14 traveling bodies will not be able to run. I don't.

Therefore, in the present invention, the valve 26 is closed and compressed air is supplied from the air supply pipe 12. Press fit and pressurize the entire inside of the conduit 9. When the valve 26 is then suddenly opened, the compressed air in the conduit 9 is rapidly reduced and released from the valve 26, and a rapid airflow is generated in the conduit 9 from the departure side to the arrival side. The traveling body 14 is carried away by this rapid airflow and travels toward the end of the conduit 9. When the traveling body 14 has stopped again, the process of closing the reproducing valve 26 to pressurize the inside of the guide α9, fully opening the valve 26, and pushing away the traveling body 14'a with the airflow is repeated.
4 to reach the end of the reach side. Whether or not the insertion has been completed can be confirmed by checking whether the string-like object 14 has passed through the transparent tube 24 or not.

According to the present invention, the airflow generated in the conduit 9 causes the traveling body 1 to
4′! ! Since the pipe is made to travel 1", a large pressure difference is generated locally before and after the traveling body 14, and the traveling body 14 is made to travel with a large force. Even if the pipe is small in diameter and has 181 curves,
A because the string-like object IO can be inserted through it. Moreover, the airflow not only causes the traveling body 14 to run, but also acts to wrap around the string-like object 10 extending behind the traveling object 14 in the airflow, and to also try to sweep away the string-like object 10'z. ,
Frictional resistance between the string-like object 10 and the inner wall of the tube is reduced, making it easier to twist the tube. Furthermore, in the case of the conventional method, T
In the cross section 5, the traveling body tries to move forward, so
However, according to the method of the present invention, the traveling body is swept away by the air current, so it can travel along the original route of the pipe 24. be.

Furthermore, even in the conventional method, if the entire compressed air is supplied by a compressor with a large discharge volume, it is possible to carry the traveling object along with the airflow and sweep it away, but depending on the location, such a large-capacity compressor may not be fully used. In the present invention, airflow noise is generated by intermittently injecting compressed air into the pipe and then releasing it suddenly, so a small compressor with a small volume of ft is sufficient. can reach the goal.

Claims (1)

[Claims] 1. A method in which a running body to which the tip of a string-like object is later joined is inserted into a pipe, and the running body is caused to travel inside the pipe by gas pressure, so that the string-like object is inserted over the entire length of the pipe. Close the end of the tube on the side where the traveling body reaches, and pressurize the inside of the tube by feeding a gas into the tube from the end of the tube. A method in which a string-like object is inserted into a pipe in which a sudden airflow is generated in the pipe by rapidly opening the 'r'Ft sign.