JPH0356360B2 - - 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 (hemp skin) used as a sealing material has weathered and its sealing performance has deteriorated, but the load of vehicles passing on the road and earthquakes can change the joint condition of pipe joints, causing 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 seen in, for example, Japanese Patent Application Laid-open No. 59-40088. Repairs such as filling are being carried out.

The above-mentioned repair pig is equipped with a replacement function that allows the resin to replace air and fill the space between the joints while discharging the air stagnant between the joints. In addition, a conventional technique in which a replacement groove and a filling groove are formed is known, for example, in the prior art described in Japanese Patent Publication No. 58-53584.

The present applicant previously proposed a device as shown in FIG. 1 as a pipe joint repair device using the above-mentioned replacement pig. That is, two first and second pigs 1 and 2, front and rear, are inserted into the existing pipe A, a resin is interposed between the two pigs, and the first pig 1 is penetrated and connected to the second pig 2. By pulling the pulling rope 3, pressure (filling pressure) is applied to the resin and the resin is moved inside the pipe. A filling groove 5 is provided, and when the first pig 1 corresponds to the position of the pipe joint part B during the movement process, the air remaining between the pipe joint parts B is discharged through the displacement groove 4. At the same time, the resin interposed between both the pigs 1 and 2 is substituted and filled into the space between the pipe joint part B from the filling groove 5.

[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.

In other words, when the resin interposed between both pigs 1 and 2 is moved inside the pipe by the movement of the pigs, the resin has viscous resistance between it and the inner wall surface of the pipe, and this viscous resistance results in loss of traction force, etc., and work efficiency is taken into consideration. When the traction speed is increased, the viscous resistance becomes larger and the loss of traction force increases. 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.

A possible solution to the above problem is to surround the resin with a bag, but the inner wall of the pipe has a part that protrudes into the pipe at the branch part of the branch pipe to connect the pipe. There is a problem in that this protruding portion gets caught on the bag when passing through, damaging the bag and causing the resin to unexpectedly flow out.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pipe joint repair device for an existing pipe that eliminates all of the above-mentioned problems.

[Means to solve the problem]

In order to achieve this object, 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,
The first pig has a replacement groove communicating with the front and a filling groove communicating with the rear on its outer periphery, and the second pig has a replacement groove communicating with the front and a filling groove communicating with the rear.
When the pig is pulled to the first pig side and the first pig corresponds to the position of the pipe joint part, the resin is replaced with air and filled into the space between the joint parts via the above-mentioned replacement groove and filling groove. A flexible bag is provided between the first pig and the second pig to surround the resin interposed between the two pigs, and a flexible bag is provided between the bag and the inner wall surface of the pipe. The bag is characterized by being provided with a skirt that protects the bag.

[Function] With this configuration, the resin moved into the pipe by the movement of the pig 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. Furthermore, since the resin moves within the pipe while being surrounded by the bag, the resin does not enter the branch pipe even when passing the position of the branch pipe.

Furthermore, even if the connection point of the branch pipe protrudes from the inner wall of the pipe, the bag body is protected by the skirt around it, so there is no problem of the bag body being damaged and the resin accidentally flowing out.

〔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. The 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. is open. The material is made of a soft sponge-like resin material, and the outer periphery has a replacement groove 12 and a filling groove 13.
are alternately arranged at equal intervals in the circumferential direction. The replacement groove 12 is open to the front end through a passage (for example, a pipe) 14 penetrating inside the pig 11, and the filling groove 13 is connected to the communication hole 1.
It communicates with the internal hollow part 16 via 5.

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, from the rear end of the first pig 11 to the front end of the second pig 18, for example,
Bag body 1 made of flexible material such as a fire hose
A bag 9 is installed between both pigs, and a resin is housed inside this bag body 19. Further, a cylindrical protective skirt 20 is disposed around the bag 19 so as to be located between the bag 19 and the inner wall surface of the tube and cover the bag 19, and the front end of this skirt 20 is connected to the first pig. 1
The rear end of the skirt 20 becomes a free end and extends rearward from the periphery of 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 repairing the pipe joint B of the existing pipe A, here, the pipe is divided into length units suitable for repairing the existing pipe A, and a plurality of pipe joints 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 pipe end and an insertion port B ₂ at the other pipe end, and the butt-fitting is performed. It has a connection structure in which the opening is filled with a sealing material C, which is usually called hemp skin, and the opening is plugged 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.
The resin is introduced into a bag 19 installed between the two pigs 11 and 18 with the resin contained therein. This resin is the first
In the process, for example, a penetrating agent
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, a compressive force is applied between the resin (X or Y) pigs 11 and 18, increasing the internal pressure. This internal pressure pushes the first pig 11 forward.

To explain the construction example specifically, in the first step, the bag body 19 is filled with the penetrant X, and when the first pig 11 reaches the position of the pipe joint B, the penetrant The air remaining in the space between the pipe joint B and the sealing material C is discharged, and the penetrating agent X is replaced and filled into the space from the filling groove 13. This situation is illustrated in FIG. In short, in the pipe joint B, since the space communicates in the circumferential direction, air and resin are substituted and filled through the space, and the sealing material C is filled with the penetrant X.

After a series of filling operations have been performed on several pipe joints B in the first step, putty agent Y is then filled between the pigs 11 and 18 in the second step, and the existing pipe A is filled in the same manner as above. be introduced within. Then, the surplus of the penetrant is discharged from the replacement groove 12 in the pipe joint part B, and the space between the pipe joint part B is filled with putty agent Y via the filling groove 13.

In this way, the pipe joint part B is replaced with resin during the moving stroke of the pigs 11 and 18.
At this time, pressure (filling pressure) is applied to the resin interposed between the pigs 11 and 18 and moving in the pipe. However, since the resin is surrounded by the bag 19 and its outflow to the outside is blocked, it does not come into contact with the inner wall surface of the pipe, and the contact resistance of only the first pig 11 and the second pig 18 is the traction force. The viscous resistance that occurs when the resin contacts the inner wall surface of the pipe can be completely eliminated.

Furthermore, a cylindrical skirt 2 is provided on the outside of the bag body 19.
0 is arranged, for example, even if the connecting part of the branch pipe slightly protrudes into the existing pipe A, it will not directly touch the bag body 19 and will not damage the bag body 19.
Inconveniences such as resin outflow can be avoided.

FIG. 6 shows another embodiment. In this embodiment, the bag body 19 is made of a flexible material used for fire hoses, etc., and has a shape in which the rear end is folded back and The distance between the pigs 11 and 18 can be shortened without the need for expansion. Also, the first pig 11
A ring 21 is attached to the outer periphery of the bag body 19 at a predetermined distance rearward, and this ring 21 is configured to be able to come into elastic contact with the inner wall of the existing pipe A. In between, the bag body 19 is provided with a passage 2. A skirt 20 is attached to the ring 21.

Therefore, the resin comes into contact with the inner wall of the pipe between the first pig 11 and the ring 21.
Even if there is a shortage of resin filling into the pipe joint part B during the passage of the pig 1, this can be compensated for, and even if the connection point of the branch pipe protrudes into the pipe, the inside of the pipe after the ring 21 The skirt 20 can protect the portion of the bag 19 that may come into direct contact with the wall.

〔Effect of the invention〕

As detailed above, the present invention provides the pig 11,1
The resin that is interposed between the pipes 8 and 8 and moves inside the pipe is surrounded by the bag 19 and the resin does not substantially come into contact with the inner surface of the pipe, so there is no loss of traction force due to the viscosity of the resin during the movement of the pig and the resin. Therefore, efficient traction can be achieved with only the sliding resistance of the pig, regardless of changes in traction speed.

Further, since the resin moves inside the pipe while being surrounded by the bag body 19, it is possible to prevent the resin from penetrating into the branch pipe when passing through the position of the branch pipe.

Furthermore, even if the connection point of the branch pipe protrudes from the inner wall of the pipe, the bag body 19 is protected by the skirt 20 around it, so damage to the bag body 19 is prevented and accidental leakage of resin can be avoided. can be obtained at the same time.

[Brief explanation of drawings]

FIG. 1 is a longitudinal side view showing how the repair device that has already been proposed is used, FIG. 2 is an enlarged perspective view of the main parts showing an embodiment of the present invention, and FIG. 3 is a longitudinal side view showing the same way of use. , FIG. 4 and FIG. 5 are enlarged longitudinal sectional side views showing each aspect of the construction state, and FIG. 6 is a longitudinal sectional side view of the usage mode showing another embodiment. 11...First pig, 12...Replacement groove, 13...
... Filling groove, 14 ... Passage, 15 ... Communication hole, 1
6... Internal hollow part, 17... Traction rope, 18...
...Second pig, 19...Bag body, 20...Skirt,
A... Existing pipe, B... Pipe joint, X... Penetrant,
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 first pig is pulled to the side of the second pig and the first pig and corresponds to the position of the pipe joint, the resin is replaced with air between the joint through the replacement groove and the filling groove. A flexible bag is provided between the first pig and the second pig to surround the resin interposed between the two pigs, and a flexible bag is provided between the bag and the inner wall surface of the pipe. 1. A pipe joint repair device for an existing pipe, characterized in that a skirt is provided to protect the bag body.