JPH0469318B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention repairs a pipe joint of an existing pipe that is buried underground so as to ensure sealing performance from the inner surface of the pipe while the pipe is buried underground. This invention relates to a pipe joint repair device for existing pipes.

[Conventional technology]

In recent years, existing pipes such as gas pipes and water pipes, especially those in which cast iron pipes are socket-joined with water-type joints or G-type joints, such as conduits buried under roads, have been found to have an intervening part at the pipe joint. The yarn used as a sealing material (hemp skin) weathers and the sealing performance deteriorates, and the joint condition of pipe joints changes due to the load of vehicles passing on the road or earthquakes, which can cause leakage. There is a need to repair pipe joints for leakage repair or preventive maintenance.

Conventionally, in order to repair this pipe joint, a pig is used to move resin along the inside of the pipe, as shown in, for example, Japanese Patent Application Laid-Open No. 59-40088, and during this movement, the resin is deposited into the gap of the pipe joint. Repairs such as filling are being carried out.

As the above-mentioned repair pig, the pig has a replacement function so that the air remaining in the joint gap can be discharged and the resin can be replaced with air and filled into the joint gap. Conventionally, the prior art described in Japanese Patent Publication No. 58-53584, for example, is known as a device in which a replacement groove and a filling groove are formed.

The present applicant previously proposed a device as shown in FIG. 1 as a pipe joint repair device using the above-mentioned replacement pig. In other words, inside the existing pipe A, there are two
A first pig 1 and a second pig 2 are inserted, a resin is interposed between both the pigs, and the tow rope 3 which passes through the first pig 1 and is connected to the second pig 2 is pulled. The first pig 1 is moved in the pipe while applying pressure (filling pressure), and the first pig 1 is provided with a replacement groove 4 communicating with the front and a filling groove 5 communicating with the rear on its outer circumference. First on the journey
When the pig 1 corresponds to the position of the pipe joint part B, the air remaining in the gap of the pipe joint part B is discharged through the replacement groove 4, and the air is discharged from the filling groove 5 between both pigs 1 and 2. The intervening resin is substituted and filled into the gap of the pipe joint part B.

[Problem to be solved by the invention]

However, when repairing the seal of a pipe joint using the apparatus shown in FIG. 1, the following problem occurred.

That is, between the two pigs 1 and 2, the resin subjected to the filling pressure during movement within the pipe generates viscous resistance with the inner wall of the pipe, and this viscous resistance results in loss of traction force and the like. Furthermore, when the traction speed is increased, the viscous resistance becomes larger and there is a problem in that losses such as traction force also increase. Furthermore, if there is a branch pipe that communicates with the existing pipe A, there is also the problem that resin may enter the branch pipe and solidify, blocking the flow of the branch pipe.

Therefore, when moving inside the pipe, measures have been taken to prevent the resin from coming into contact with the inner wall surface of the pipe between the two pigs, except that the first pig corresponds to the pipe joint.

However, if the pulling speed is increased for the purpose of shortening the repair work time, etc., the resin filled into the joint gap through the filling groove becomes insufficient, making it difficult to ensure sealing performance.

The present invention was proposed based on the above-mentioned circumstances, and after the first pig passes, the filling action of the resin on the pipe joint part is continued for the required time, and after that, the inner wall surface of the pipe and the resin are kept in contact with each other. To provide a pipe joint repair device for an existing pipe, which achieves efficient traction without causing viscous resistance due to the movement of the pig between the pipes, and prevents resin from entering the branch pipe.

[Means to solve the problem]

In order to achieve this objective, the present invention introduces a first pig and a second pig into an existing pipe to be repaired with a required amount of resin interposed between the two pigs, and
The pig has a replacement groove communicating to the front and a filling groove communicating to the rear on its outer periphery, and when the second pig is pulled toward the first pig, the first pig is positioned at the pipe joint. When responding to this, in a device that replaces resin with air and fills the joint gap through the replacement groove and the filling groove, the periphery of the resin is placed between the first pig and the second pig. A flexible bag body surrounding the first pig is provided, a ring that comes into elastic contact with the inner wall of the pipe is attached to the outer periphery of the bag body within a predetermined distance immediately behind the first pig, and a ring is placed between the rear part of the first pig and the ring. A resin passage is opened in the body, and the resin flowing out from the passage is brought into contact with the inner wall surface of the pipe.

[Effect]

In such a configuration, the resin that is interposed between the first pig and the second pig and moves inside the pipe is surrounded by the bag and does not come into contact with the inner wall surface of the pipe, so loss of traction force due to viscous resistance of the resin can be avoided. Also, the phenomenon of resin intruding into the branch pipes does not occur.

In addition, within a predetermined distance to the ring immediately after the first pig, some resin comes into contact with the inner wall surface of the pipe through the passage provided in the bag, and the resin does not reach the pipe joint immediately after the first pig passes. Since the filling is compensated, even if the pig is moved at a relatively fast speed to improve work efficiency, the resin filling in the pipe joint can be completely compensated immediately after the first pig passes, ensuring reliable sealing. become achievable.

In addition, some of the resin that comes into contact with the inner wall surface of the pipe through the above-mentioned passage is reduced in pressure as it passes through the passage, reducing the filling pressure, so it is possible to prevent the resin from entering the branch pipe during the pig movement process. This function will not be affected.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 2 to 7.

In FIGS. 2 to 7, reference numeral 11 denotes a first pig, and this first pig 11 has a cylindrical shape with a U-shaped cross section with a closed front end, a hollow interior, and a rear end. The ends are open. Further, the material is made of a soft sponge-like resin material, and on the outer periphery thereof, replacement grooves 12 and filling grooves 13 are arranged alternately at equal intervals in the circumferential direction. The replacement groove 12 communicates with the front end of the pig via a passage (for example, a pipe) 14 penetrating inside the pig 11, and the filling groove 13
communicates with the internal hollow part 16 via the communication hole 15.

A towing rope 17 is slidably inserted through the center of the first pig 11, and a second pig 18 is connected to the rear end of the towing rope. This second pig 18 is also made of the same material as the first pig 11, and has a solid cylindrical shape.

In the present invention, the first pig 11
A bag 19 made of a flexible material such as a fire hose is disposed behind the second pig 18 at a certain distance to the front end of the second pig 18 . The front end of this bag body 19 is connected to the rear part of the first pig 11, and the rear end is folded back so that the distance between the first pig 11 and the second pig 18 can be shortened without expanding in the radial direction. I'm starting to be able to do it. In addition, the first pig 11
A ring 20 is attached to the outer periphery of the bag body 19 at a predetermined distance rearwardly, and this ring 20 can be brought into elastic contact with the inner wall of the existing pipe A.
A passage 21 is provided in the bag 19 between the pig 11 and the ring 20. Note that the inside of the bag body 19 is filled with resin between the first pig 11 and the second pig 18.

Next, a situation in which the pipe joint of the existing pipe A is repaired using the above-mentioned repair device will be explained.

Here, the existing pipe A buried underground is connected to a cast iron pipe using the conventional piping method, and the pipe joint B
It has been connected for a long time via . In order to repair the pipe joint part B of the existing pipe A, here, the pipe is divided into length units suitable for repairing the existing pipe A, and the plural pipe joint parts B interposed within that section are repaired. As is well known in the art, for example, the pipe joint part B has a large-diameter socket B ₁ provided at one end of the pipe, and an insertion port B ₂ at the other end of the pipe butt against each other. It has a connection structure in which a sealing material C, usually called hemp skin, is filled in the joint, and the opening is sealed with a lead material D.

The first pig 11 and the second pig 18 are inserted into the existing pipe A to be repaired from one opening thereof.
A bag 19 between both pigs 11 and 18 is filled with resin and introduced. In the first step, this resin is used as a penetrant X
However, in the second step, high viscosity resin (for example, 10,000
cps to 300,000 cps) is filled and moved inside the existing pipe A in the direction of the arrow by being pulled by the pulling rope 17. During this movement, it is preferable that negative suction pressure be applied to the front of the first pig 11. As the second pig 18 is pulled forward by the rope 17, the resin (X or Y) is subjected to compressive force between the pigs 11 and 18, increasing the internal pressure. The first pig 11 is pushed forward by this internal pressure.

To explain a construction example specifically, in the first step, the bag body 19 between the first pig 11 and the second pig 18 is
When the first pig 11 reaches the position of the pipe fitting B, the air remaining in the gap space of the pipe fitting B and the sealing material C is removed through the displacement groove 12. is discharged, and there is a filling groove 13.
Penetrant X is displace-filled from there. This situation is illustrated in FIG. In short, in the pipe joint part B, a gap space is created in the circumferential direction and communicates with each other, so air and resin are replaced through the gap space, and the sealing material C is filled with the penetrant X. .

At this time, the pulling speed of the towing rope 17 is too fast, the passing speed of the first pig 11 passing through the position of the pipe joint part B is too fast, and even if the time for replacing and filling the above-mentioned penetrant X (resin) is short. , immediately after the first pig 11,
Some of the resin that passes through the passage 21 and flows between the first pig 11 and the ring 20 comes into contact with the inner wall surface of the pipe,
The resin whose pressure is lowered when passing through this passage 21,
Since the filling action is compensated for the pipe joint part B immediately after the first pig 11 passes, insufficient filling of the gap space of the pipe joint part B will not occur.

Note that the first pig 11 passes through the passage 21 described above.
A part of the resin flowing between the ring 20 and the ring 20 is reduced in pressure when passing through the passage 21, and the filling pressure is lowered, so that the resin does not enter the branch pipe.

After a series of filling operations have been performed on several pipe joints B, next, as a second step, the pigs 11, 1
8 is filled with putty agent Y, and the existing pipe A is filled in the same way as above.
be introduced within. This time, the surplus of the penetrant is discharged from the replacement groove 12 in the pipe joint part B, and the putty agent Y is filled into the gap space of the pipe joint part B via the filling groove 13. If there is insufficient filling, when the space between the first pig 11 and the ring 20 passes through the pipe joint B, the putty Y is filled to compensate for this, ensuring complete sealing.

Moreover, due to the function of the bag body 19, the resin does not come into direct contact with the inner wall surface of the existing pipe A except between the first pig 11 and the ring 20. In addition, the resin pressure is slightly lowered between the first pig 11 and the ring 20 (pressure drop due to passing through the passage 21), and resin intrusion into the branch pipe is substantially prevented. is prevented.

In the embodiment shown in FIG. 7, the bag body 19 is made of a flexible material used for fire hoses, etc., and the rear second pig 18 has an air hole 22 in the center. The rear end of the towing rope 17 is connected to a piston pig 23 which is slidably movable into the bag body 19. Therefore, in this type, the distance between the first pig 11 and the second pig 18 is constant, and as the piston pig 23 moves, the resin in the bag body 19 receives filling pressure.

Further, in this embodiment, the ring 20 is used as the sealing member, but it is of course possible to use a ring 20 of other shapes.
Any configuration is sufficient as long as the filling pressure of the resin in contact with the pipe wall surface between the ring 1 and the ring 20 can be reduced to an extent that can prevent large intrusion into the branch pipe.

〔Effect of the invention〕

As described in detail above, the present invention provides the first pig 1
Since the resin that is interposed between the first and second pigs 18 and moved inside the pipe is surrounded by the bag 19 so that most of it does not come into contact with the inner wall surface of the pipe, loss of traction force due to viscous resistance of the resin is avoided. Further, it is possible to prevent the resin from entering the branch pipe.

Moreover, within a predetermined distance to the ring 20 immediately after the first pig, some of the resin comes into contact with the inner wall surface of the pipe through the passage 21 provided in the bag body 19, and the resin contacts the pipe joint immediately after the first pig 11 passes through. However, since the resin filling is compensated, even if the pig is moved at a relatively fast speed to improve workability, the resin filling in the pipe joint will not be insufficient, and the pipe fitting will not be filled with resin immediately after the first pig passes. can be completely compensated for and achieve reliable sealing performance.

Note that some of the resin that comes into contact with the inner wall surface of the pipe through the above-mentioned passage 21 is lowered in pressure when passing through the passage 21 and the filling pressure is lowered, so the resin may not enter the branch pipe during the movement of the pig. It does not interfere with the effect of preventing.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal side view showing how the compensation device that has already been proposed is used, FIG. 2 is an enlarged perspective view of the main part showing one embodiment of the present invention, and FIG. 3 is a longitudinal side view showing the same way of use. , FIGS. 4 to 6 are enlarged vertical side views showing various aspects of the construction state, and FIG. 7 is a vertical side view of another embodiment. DESCRIPTION OF SYMBOLS 11... First pig, 12... Replacement groove, 13... Filling groove, 14... Passage, 15... Communication hole, 16... Internal hollow part, 17... Traction rope, 18... Second pig, 19
... Bag body, 20 ... Ring, 21 ... Passage, 22 ... Air hole, 23 ... Piston pig, A ... Existing pipe, B ... Pipe joint part, B ₁ ... Large diameter socket, B ₂ ... Insertion port, C...
Sealing material, D...lead material, X...penetrating agent, Y...putty agent.

Claims (1)

[Claims] 1. A first pig and a second pig are installed in the existing pipe to be repaired.
A pig is introduced with a required amount of resin interposed between both pigs, and the first pig has a replacement groove communicating to the front and a filling groove communicating to the rear on its outer periphery, When the second pig is pulled toward the first pig side and the first pig corresponds to the position of the pipe joint, the resin is replaced with air in the joint gap through the replacement groove and the filling groove. In the filling device, a flexible bag surrounding the resin is provided between the first pig and the second pig, and the inner wall of the tube and the elastic The existing construction is characterized in that a contacting ring is attached, a resin passage is opened in the bag body between the rear part of the first pig and the ring, and the resin flowing out from the passage is brought into contact with the inner wall surface of the pipe. Pipe joint repair equipment.