JPS6249848B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a method for inserting a flexible cylindrical body into pipes mainly buried underground, such as underground pipes such as gas pipes, water pipes, power lines, and communication lines. It concerns a method for doing so. The flexible cylindrical body inserted here can be adhered to the inner surface of the tube to serve as a lining, or can be used temporarily to perform some kind of treatment inside the tube.

As a method for inserting a flexible cylindrical body into a pipe, the tip of the flexible cylindrical body is fixed in a tubular shape at one end of the pipe, and fluid pressure is applied to the rear part of the annular fixed part. By turning the flexible cylindrical body over so that the inside becomes the outside at the folded part formed on the annular fixed part, and moving the folded part forward inside the pipe from the one end to the other end of the pipe, the entire length of the pipe can be adjusted. A method is known in which a flexible cylindrical body is inserted through the body. This method allows long pipes to be inserted easily and in a short time, and in the case of underground pipes, construction can be carried out with most of the pipe remaining underground by simply digging up both ends. In recent years, this method has attracted particular attention as an extremely excellent method that can be applied even if the pipe is bent.

In addition, in the case of the above method, high pressure is required to turn over the flexible cylindrical body in the case of a relatively small diameter tube. A method is known in which a string-like elongated object is inserted through the tube and the string-like elongate object is pulled from the other end of the tube to advance the inside-out of the flexible cylindrical body. This method allows the flexible cylindrical body to be inserted through even a fairly small diameter tube, and requires less fluid pressure.
It has the advantage of being less dangerous.

However, in the case of gas conduit pipes, small diameter pipes are the terminal pipes that supply gas to each household, and such pipes are usually severely bent. When the above-mentioned method is applied here, as shown in FIG.
is pulled forward while being rubbed against the inside of the bent portion of the tube 3, and if the inner surface of the tube 3 is uneven and rough, the string-like long object 2 is extremely susceptible to damage and often It may break. When the string-like elongated object 2 breaks, it is no longer possible to turn the flexible cylindrical body 1 inside out, and after the rear end of the flexible cylindrical body 1 has already been drawn into the tube 3. There is no way to reverse this, and there is nothing that can be done about it.

The present invention has been made in view of the above circumstances, and is capable of preventing the breakage of the string-like long object in the above method and safely and reliably inserting the flexible cylindrical body over its entire length. The purpose is to provide a method.

FIG. 2 shows a flexible cylindrical body 1 produced by the method of the present invention.
This provides a method for inserting the tube into the tube 3.
Reference numeral 4 is a flexible sheath tube that is thinner than the tube 3, and is inserted halfway into the tube 3 from the other end side. The flexible cylindrical body 1 has its tip fixed to one end of the tube 3 in an annular shape. The string-like elongated object 2 is inserted through the flexible cylindrical body 1 and the tube 3, and inside the tube 3, it is inserted into the sheath tube 4. The sheath tube 4 needs to have enough flexibility to bend along the curve of the tube 3, but preferably has enough rigidity to prevent it from being easily flattened by external force. Further, the inner surface of the sheath tube 4 preferably has low frictional resistance with the string-like elongated object 2 and does not have irregularities that may damage the string-like elongated object 2. Further, the sheath tube 4 does not need to be airtight at all. A specific example of the sheath tube used in the present invention is, for example, a tight helical spring. The tight helical spring has enough flexibility to be easily bent due to its own elasticity, and will not be crushed by external force. In addition, the inner surface is smooth although there are irregularities due to the winding, and the frictional resistance with the string-like long object 2 is small so that it will not be damaged.
It is extremely excellent.

In the present invention, fluid pressure is applied to the rear part of the annular fixed portion of the flexible cylindrical body 1 while the sheath tube 4 is fixedly supported with respect to the tube 3 while only the string-like elongated object 2 is attached. pull forward. As a result, as described in the previous conventional example, the flexible cylindrical body 1 is turned over at the folded portion 1a so that the inside becomes the outside, and the folded portion 1a advances inside the tube 3 from one end to the other end. do. At this time, the sheath tube 4 is inserted halfway from the other end into the tube 3, and the string-like long object 2
is inserted into the sheath tube 4, so the frictional resistance between the string-like long object 2 and the sheath tube 4 in this part is significantly reduced, and the load applied to the string-like long object 2 is small. I'm done. Therefore, even if there is a part where the tube 3 and the string-like long object 2 come into direct contact and cause friction, the load applied to the string-like long object is small.
It is hard to get scratched and will not break.

When the flexible cylindrical body 1 is turned inside out and the folded portion 1a moves forward, the folded portion 1a moves toward the sheath tube 4.
I hit the terminal and can't proceed any further.
This can be recognized by the sudden increase in the tensile load on the string-like elongated object 2. Once this state is reached, the sheath tube 4 is pulled together with the string-like elongated object 2. Then, since the forward speed of the folded portion 1a of the flexible cylindrical body 1 is half the pulling speed of the string-like elongated object 2, the sheath tube 4 advances and the folded portion 1a moves forward.
a can move further forward, and the distance between the end of the sheath tube 4 and the folded portion 1a increases. When the gap has opened to a certain extent, the forward movement of the sheath tube 4 is stopped again, and only the string-like long object 2 is pulled, and the folded part 1
Move a forward. By repeating this process, the sheath tube 4 is intermittently pulled out and removed from the other end of the tube 3, and the flexible cylindrical body 1 is removed from the folded portion 1.
a moves forward while following the end of the sheath tube 4 and is turned over over its entire length, allowing the tube 3 to pass through the turned over flexible cylindrical body over its entire length.

In the present invention, the range through which the sheath tube 4 is inserted is such that excessive resistance to the advancement of the string-like elongated object 2 does not occur due to friction with the inner surface of the tube 3 between its terminal and one end of the tube 3. It is only necessary to insert it within the range of , and there is no need to insert it closer to one end than necessary.
Further, in the previous explanation, the sheath tube 4 was advanced after the folded portion 1a hit the end of the sheath tube 4, but this does not necessarily have to happen, and the folded portion 1a hits the end of the sheath tube 4. The sheath tube 4 may be advanced after approaching to a certain extent. Folded part 1
The distance between a and the end of the sheath tube 4 can be calculated from the length of the string-like elongated object 2 pulled out and the length of the flexible cylindrical body 1 pulled into the tube 3. Also, sheath tube 4
When moving the string-like long object 2 forward, it may be moved forward together with the string-like long object 2, but the tension on the string-like long object 2 is temporarily stopped and only the sheath tube 4 is advanced, and then the sheath tube 4 is stopped again. The string-like elongated object 2 can also be pulled.

In the present invention, the folded portion 1a is the sheath tube 4.
The same effect can be obtained by simultaneously advancing the string-like elongated object 2 and the sheath tube 4 at twice the speed of the latter after reaching or approaching the end of the string. , the flexible cylindrical body 1, the string-like elongated object 2, and the sheath tube 4 partially expand and contract, and the tube 3
Since the inside cannot be visually observed from the outside, it is not possible to accurately know the position of the folded portion 1a or the end of the sheath tube 4, and furthermore, the flexible cylindrical body 1 and the sheath tube 4 cannot be accurately located.
Since it is difficult to make the sheath tube 4 advance at different speeds, it is better to advance the sheath tube 4 intermittently as in the present invention.

According to the present invention, it is possible to insert the flexible cylindrical body 2 even through a small-diameter and complicatedly bent tube, and the load applied to the string-like long object during insertion is small, making it possible to inadvertently The long cord-like object will not break and can be inserted smoothly. The flexible cylindrical body 2 inserted by the method of the present invention is adhered to the inner surface of the tube 3 by fluid pressure after being turned over by applying an adhesive to its inner surface in advance.
It can be the lining of the tube 3. Further, by pulling out the inserted flexible cylindrical body, other articles connected to the end thereof can be inserted into or passed through the tube 3. It is also possible to perform various treatments on the tube 3 using this flexible cylindrical body.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a state in which a flexible cylindrical body is inserted into a tube by a conventional method, and FIG. FIG. DESCRIPTION OF SYMBOLS 1... Flexible cylindrical body, 1a... Folded part, 2... String-like long object, 3... Tube, 4... Sheath tube.

Claims (1)

[Claims] 1 Annularly fixing the tip of the flexible cylindrical body at one end of the tube, and inserting a string-like elongated object through the flexible cylindrical body and the tube to apply fluid pressure to the rear part of the annular fixed part. By pulling the string-like elongated object from the other end of the tube while applying the action, the flexible cylindrical body is turned so that the inner side is the outer side at the folded part of the flexible cylindrical body formed in the annular fixed part. A method of inserting a flexible cylindrical body that has been turned inside out over the entire length of the tube by advancing the folded part inside the tube from one end of the tube toward the other end while turning it inside out. A thin and flexible sheath tube is inserted, and the string-like elongated object is inserted into the sheath tube, and the string-like elongate object is pulled while firmly supporting the sheath tube to the tube to form a flexible cylindrical tube. The folded part is advanced while turning the body over, and when the folded part reaches or approaches the end of the sheath tube, the sheath tube is advanced alone or together with a string-like elongated object to remove the sheath tube. A flexible cylindrical tube is inserted into the tube, which is characterized by repeating the steps of opening the gap between the end and the folded part, stopping the forward movement of the sheath pipe, and pulling only the string-like long object to advance the folded part. How to insert the body inverted.