JPH0561516B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is designed to ensure sealing performance from the inner surface of the pipe while the pipe joint part of an existing gas pipe, etc., is mainly buried underground. This invention relates to a pipe joint repair device for existing pipes.

[Conventional technology]

In recent years, various methods have been proposed for repairing existing pipes such as gas pipes, water pipes, etc. buried underground for the purpose of rehabilitating and repairing the pipes from inside the pipes while the pipes are still buried. In particular, in gas pipelines laid under roads, where cast iron pipes are socket-connected with water-type joints or G-type joints, the yarn (hemp skin) interposed in the pipe joints weathers and seals. Pipe joints should be repaired for the purpose of leakage repair or preventive maintenance, as the joint condition of the joint may change due to the load of vehicles passing on the road or earthquakes, causing leakage. The need has arisen.

Conventionally, this type of pipe joint repair has been carried out by moving liquid resin inside the pipe with a towing pig, as shown in Japanese Patent Application Laid-Open No. 59-40085, and when the resin corresponds to the position of the pipe joint during the movement process. A repair method has been used to infiltrate and fill the space between the joints with resin.

The present applicant previously filed Japanese Patent Application No. 58-103403 (Japanese Unexamined Patent Publication No. 59-231290) as a towing pig used for the above-mentioned repair.
With this, two annular recesses are formed on the outer periphery of the pig body that moves inside the existing pipe, with the front annular recess serving as a negative pressure chamber and the rear annular recess serving as a resin filling chamber. In the axial direction, a groove for resin filling that opens toward the resin filling chamber on the rear side and a groove for displacing air that opens toward the negative pressure chamber on the front side are provided on the outer periphery of the intermediate pig of the two front and rear chambers. Both grooves are provided at different positions in the circumferential direction so that their opposing ends overlap so that they do not communicate with each other, and the resin filling chamber is provided with a cylindrical flexible bag capable of expanding its volume. We have proposed a structure in which filling pressure is applied to the resin by positive pressure applied to the flexible bag, so that the resin is reliably replaced and filled into the space between the pipe joints.

[Problem to be solved by the invention]

By the way, when repairing a pipe joint using the above-mentioned repair pig proposed above, there were problems as described below.

In other words, in the existing pipe to be repaired, there may be rust, accumulation of dust, accumulation of tar components, etc. on the inner wall of the pipe, and it is necessary to remove the negative pressure chamber on the front side and the resin filling chamber on the rear side. If the outer periphery of the partitioning intermediate pig rides on the airtightness between the two chambers, the filling pressure that acts on the resin will pass through to the negative pressure chamber and leak between the pipe joints. A problem arises in that the displacement and filling effect of the resin inside the tube is poor.

In addition, the existing pipe to be repaired has branch pipes branched off at various locations along the pipe line, and when the pig body passes through the branch pipe branch positions, if there is a large amount of resin stored in the resin filling chamber, the resin There is also the problem that it penetrates deeply into the branch opening of the branch pipe and blocks the branch pipe.

The present invention improves the previously proposed repair pig so that the above-mentioned problems do not arise, and thereby provides a pipe joint for existing pipes that has a high sealing effect on the pipe joint and simultaneously prevents resin from entering branch pipes. The purpose of this invention is to provide a partial repair device.

[Means to solve the problem]

In order to achieve this objective, the present invention forms two annular recesses at the front and the rear on the outer periphery of the pig body that moves in airtight contact with the piping surface of the existing pipe. Inside the side recess, a cylindrical flexible bag that can expand the volume is provided concentrically, and a pressurized chamber is formed on the inside and a resin filling chamber is formed on the outside. The air supply pipe is connected to apply positive pressure to the flexible bag to apply filling pressure to the resin in the resin filling chamber, and the pressurized chamber and the pressure fluctuation chamber are connected through a communication path to form the pressure fluctuation chamber. The resin filling chamber has a configuration in which positive pressure is applied to the resin filling chamber, and the pressure is regulated so that the internal pressure in the resin filling chamber is always maintained higher than the internal pressure in the pressure fluctuation chamber.

[Effect]

With this configuration, the intermediate outer periphery of the pig body rides on rust, ducts, tar component accumulation, etc. occurring inside the pipe to be repaired, and the airtightness between the front and rear pressure fluctuation chambers and the resin filling chamber is reduced. Even if the pipe joint collapses, the internal pressure due to the pressure fluctuation is regulated to be low relative to the resin filling chamber, so that no problem will occur that would impede the replacement and filling action of the resin in the pipe joint.

In addition, when the pig body passes through a branch point of a branch pipe branched from the existing pipe line, when the pressure fluctuation chamber corresponds to the branch opening of the branch pipe, pressurized air escapes to the outside through the branch pipe. As a result, the pressure in the pressurizing chamber is reduced and the flexible bag contracts, so that the resin passes through the pipe while being drawn to the contracted position of the flexible bag.

During this process, when the pressure fluctuation chamber passes through the branch opening of the branch pipe, the pressure fluctuation chamber is closed by the inner wall of the existing pipe, so even though the flexible bag begins to expand, the resin filling chamber is closed on the branch pipe. During the time it takes for the pipe to move to the position corresponding to the branch opening, the resin is not pressed against the inner wall of the pipe, so the resin does not enter the branch opening of the branch pipe. .

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

1 to 3, reference numeral 1 indicates a cylindrical pig body introduced into the existing pipe A to be repaired, and a traction wire 2 is passed through the center of the inside of the pig body, and The pig body 1 is fixed via disks 3, 3 provided at its front and rear ends. The pig body 1 includes a front pig 4, an intermediate pig 5
and a rear pig 6, which are connected by a small-diameter body 7, 8 to form a monolithic structure.

The first annular recess formed between the front pig 4 and the intermediate pig 5 serves as a pressure fluctuation chamber 11, and the inside of the second annular recess formed between the intermediate pig 5 and the part pig 6 is The interior thereof is partitioned into an inner and outer part by an inflatable cylindrical flexible bag 14 made of a rubber membrane or the like, with the inside being a pressurizing chamber 15 and the outside being a resin filling chamber 16.
It is becoming.

The pressure fluctuation chamber 11 and the pressurizing chamber 15 are communicated with each other by a communication passage 9 extending through the intermediate pig 5, and the pressurizing chamber 15 is connected to a positive pressure supply pipe passing through the rear pig 6. 12 is opened for communication, and this positive pressure supply pipe 12 extends rearward in the direction of movement of the pig body 1 and is connected to a compressor 13 via a flexible hose.

A restrictor 24 is provided in the communication passage 9 that communicates the pressure fluctuation chamber 11 and the pressurization chamber 15, and the pressure fluctuation chamber 11 has a passage 25 that passes through the front pig 4 and exits forward. A diaphragm 26 is provided there.
These throttles 24 and 26 provide a pressure difference between the pressurizing chamber 15 and the pressure fluctuation chamber 11, and the pressure in the pressurizing chamber 15 is P ₁ and the pressure in the resin filling chamber 16 is P ₂ .
When the pressure inside the pressure fluctuation chamber 11 is P ₃ and the atmospheric pressure in front of the pig body 1 is P ₀ , the relationship is set such that P ₀ < P ₃ < P ₂ < P ₁ , and in particular, P ₃ − The pressure difference of P ₂ is made so large that it does not affect the displacement during filling. For example, the above P ₁ = 1Kg/cm ² , P ₃ = 0.2Kg/cm ²
Set to a certain degree.

Furthermore, as shown in detail in FIG. 2, the intermediate pig 5 has a resin-filled groove 17 opening toward the rear side in the direction of movement, and a resin-filled groove 17 that opens toward the rear side in the direction of movement, with the intention of providing a replacement function to be described later. The substituted product discharge groove 18, which opens toward the front of the groove, is positioned so that the opposing ends thereof overlap in the axial direction, and the grooves 17 and 18 do not communicate with each other in the circumferential direction. It is formed as follows. The above substituted material discharge groove 18
is communicated with a passage 18a that penetrates inside the pig body 1 and opens in front of the pig, and this passage 18a
is connected to the vacuum pump 10 via a hose 10a.

Further, as shown in FIG. 3, in front of the pig body 1 introduced into the existing pipe A, a magnetic sensor block 19 is installed at a predetermined distance from the pulling wire 2.
is fixed to. Block 1 for this magnetic sensor
9 is provided with a plurality of magnetic sensors 20 at circumferentially divided positions, and a signal sending cable 21 thereof extends forward. The traction wire 2 is provided with a scale for measuring the length, and is wound around winches 22 and 23 at the front and back, respectively.

The existing pipe A buried underground to be repaired is a cast iron pipe connected to long pipe joints B and C using conventional piping methods. It is divided into repair sections, and a plurality of pipe joints B and C interposed in this section are repaired for sealing in a series of steps. Here, the pipe joint part B is
As is well known in the art, for example, a large-diameter socket B ₁ provided at one end of the pipe abuts the end B ₂ of the other pipe, and the abutting fitting part is usually provided with a "hemp skin".
It is of a connection structure in which a sealing material D called . In addition, the other pipe joint part C is formed by fitting a large diameter joint member C ₁ so as to cover the ends of the pipes facing each other,
It has a connection structure in which the fitting part is filled with sealing material D and the opening is sealed with lead material E, and this pipe joint part C also leaves some air space F at the abutting end. ing.

During repair, the pig body 1 is introduced into the existing pipe A from one opening thereof. In this introduction, the resin filling chamber 16 of the pig body 1 is divided into a first step and a second step in this construction example. In the second step, a filling putty agent Y of high viscosity resin (for example, 10,000 to 300,000 cps) is stored and moved inside the existing pipe A by pulling the wire 2.

During this movement process, when the magnetic sensor block 19 comes to the position of the pipe joint B (or C), all the magnetic sensors 20 react and output a signal, which can be captured on the ground. If only one magnetic sensor 20 reacts, it can be detected that the branch pipe is connected.

Due to the reaction of the magnetic sensor 20, the pipe joint part B
Based on confirming the location of (or C),
The pig body 1 is connected to the pipe joint part B as shown in FIG.
(or C), the movement of the pig body 1 is temporarily brought to a low speed state at this position.

In this state, first, the vacuum pump 10 is operated to apply a negative pressure suction force to the displacement air exhaust groove 18, and in this state, the pig body 1 slowly advances from the state shown in FIG. As shown in FIG. 5, when the outer periphery of the intermediate pig 5 advances to a position corresponding to the air space F of the pipe joint B, the negative pressure applied to the substitute discharge groove 18 is applied to the air space F and the pipe joint B. Dust and air that reach the sealing material D and stay there are sucked and removed in front of the pig via the passage 18a. In this state, the substituent discharge groove 18 and the resin filling groove 17 are in communication with each other via the air F, so that if air remains in the resin filling chamber 16, this is also suctioned out using negative pressure. be done.

During this process, when pressurized air is applied to the pressurizing chamber 15 from the compressor 13, the flexible bag 14
Due to the expansion of the volume, a pressing force in the direction shown by the arrow acts on the penetrant X housed in the resin filling chamber 16, and the filling pressure causes the penetrant X to flow into the air F through the resin filling groove 17. The penetrant X is pushed in and displaces and fills the air F and the sealing material D while discharging the air in the air F through the substituent exhaust groove 18.

When replacing the resin at the pipe joint part B, even if the airtightness of the intermediate pig 5 is destroyed due to rust, dust, or accumulation of tar components occurring inside the pipe, the pressure fluctuation chamber 1
As described above, the internal pressure of the chamber 1 is adjusted to be lower than that of the pressurizing chamber 15 and the resin filling chamber 16, so that no inconvenience that would impede the displacement and filling action of the resin (penetrant X) occurs.

After filling one pipe joint B (or C) with penetrant X, insert the pig body 1 again.
It is towed and moved at the required speed to the position corresponding to the next pipe joint part B (or C).

Next, a case will be described in which the pig body 1 passes through a location where a branch pipe G is branched from the existing pipe A as shown in FIG. 6 in this movement process.

The end of this branch pipe G is opened to the atmosphere in advance prior to repair work. In this state, the pig body 1 is towed and moved, and the magnetic sensor block 1 is
9, the branch of the branch pipe G is detected because only that one magnetic sensor 20 reacts. Based on the detection, the process proceeds with the compressor 13 operating, and due to its movement, the pressure fluctuation chamber 11
When the position corresponding to the branch opening of the branch pipe G is reached as shown in FIG. 6, the pressurized air given by the compressor 13 enters the pressure fluctuation chamber 11 from the pressurizing chamber 15 via the communication path 9, and Furthermore, it is discharged to the outside through the branch pipe G. As a result, the pressure in the pressurizing chamber 15 decreases and the flexible bag 14 contracts, so that no pressing force acts on the resin (penetrant X) housed in the filling chamber 16 and the flexible bag 14 contracts. It moves through the tube while being pulled into position.

When the pressure fluctuation chamber 11 passes through the branch opening of the branch pipe G during advancement, the pressure fluctuation chamber 11 becomes flexible because it is closed by the inner wall of the existing pipe A by the front pig 4 and the intermediate pig 5. Although the bag 14 begins to expand, the resin (penetrating agent Since this does not occur, the phenomenon that the resin (penetrating agent X) enters the branch opening of the branch pipe G does not occur. Therefore, the time lag can be easily achieved by setting the pulling speed of the pulling wire 2, the supply speed of compressed air by the compressor 13, etc.

Of course, a pressure sensor is installed in the pressure fluctuation chamber 11 to detect the pressure drop when passing through the branch pipe G, and then the compressor 13 is stopped for a certain period of time while the pig body 1 passes through, or the throttle valve is closed. may also be controlled.

Alternatively, pressurized air may be supplied from the part of the branch pipe G that is open to the atmosphere for a certain period of time based on the detection by the pressure sensor.

In this way, while the pig body 1 passes through the branch opening of the branch pipe G, the resin contained in the resin filling chamber 16 is prevented from entering into the pipe of the branch pipe G.

Through the above-mentioned process, the penetrant X is replaced and filled in each pipe joint part B, and the amount of the residual penetrant X decreases as the repair progresses. However, this is a flexible bag 1
4 expansion allows filling pressure to be applied to the resin until substantially the final stage.

After the filling action of penetrating agent It is moved into the pipe A, and the putty agent Y is pressurized and filled into the pipe joint part B (or C) (see FIG. 7). In this case, a surplus of the previous penetrating agent X remains in the air F, but this is suctioned and discharged to the vacuum pump 10 side via the substitute discharge groove 18, and the putty agent Y is filled with the filling pressure. is added, the putty agent Y is substituted and filled into the space between the pipe joints B in place of the excess penetrant X.

In the above-mentioned embodiment, the pig body 1 is composed of an integral structure having two chambers, but the front pig 4, middle pig 5 and rear pig 6 are constructed separately and connected to each other. Of course, a configuration may also be used.

Also, a passage 18 provided through the pig body 1
The hose 10a communicating with the pig body 1 may simply open in front of the pig body 1 without performing negative pressure suction.

〔Effect of the invention〕

As described in detail above, according to the present invention, the intermediate outer periphery of the pig body 1 rides on the accumulation of rust, dust, tar components, etc. occurring inside the pipe to be repaired, and the front and rear pressure fluctuation chambers 11 and the resin filling Even if the airtightness between the pressure fluctuation chamber 11 and the chamber 16 is broken, the internal pressure of the pressure fluctuation chamber 11 is regulated to be lower than that of the resin filling chamber 16, which is an inconvenience in that it interferes with the replacement and filling action of resin on the pipe joint. The resin is reliably filled into the gap between the pipe joints and repairs can be performed with a high sealing effect.

In addition, when the pig body 1 passes through a branch point of a branch pipe branched from the existing pipe line, when the pressure fluctuation chamber 11 corresponds to the branch opening of the branch pipe, pressurized air flows outside through the branch pipe. As a result, the pressure in the pressurizing chamber 15 decreases and the flexible bag 14 contracts, which prevents the resin from entering the branch opening of the branch pipe and prevents clogging of the branch pipe. Effects such as being able to do this can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention;
FIG. 2 is a perspective view of the same, FIG. 3 is an overall longitudinal sectional perspective view showing how it is used, and FIGS. 4 to 6 are partially enlarged longitudinal sectional views illustrating the penetration state of the penetrant in the first step.
FIGS. 7 and 8 are partially enlarged vertical cross-sectional views illustrating the state of penetration of the putty agent in the second step. 1... Pig body, 2... Traction wire, 3... Disc, 4, 5, 6... Pig part, 7, 8... Body part,
9...Communication path, 10...Vacuum pump, 10a...
Hose, 11... Pressure fluctuation chamber, 12... Positive pressure supply pipe, 13... Compressor, 14... Flexible bag, 15... Pressurization chamber, 16... Resin filling chamber, 17
...Resin filling groove, 18... Substitute discharge groove, 18a
...Aisle, 19...Block, 20...Sensor,
21... Cable, 22, 23... Winch, 2
4... Aperture, 25... Passage, 26... Aperture, A...
...Existing pipe, B...Pipe joint part, B ₁ ...Large diameter part,
B ₂ ...Pipe end, C...Pipe joint, D...Seal material,
E...Lead material, F...Empty, G...Branch pipe, C ₁ ...
Pipe joint parts.

Claims (1)

[Scope of Claims] 1. Two annular recesses are formed on the outer periphery of the pig body 1, which is towed and moved in airtight contact with the inner surface of the existing pipe. A cylindrical flexible bag 14 capable of expanding its volume is provided concentrically within the recess, and a pressurizing chamber 15 is formed on the inside thereof, and a resin filling chamber 16 is formed on the outside. A pressure air supply pipe 12 is communicated with the flexible bag 15 to apply filling pressure to the resin in the resin filling chamber 16 by the positive pressure acting on the flexible bag 14. 9 to communicate with each other to apply positive pressure to the pressure fluctuation chamber, and the internal pressure in the resin filling chamber 16 is equal to the pressure fluctuation chamber 11.
A pipe joint repair device for an existing pipe, characterized in that the pressure is regulated so that it is always maintained higher than the internal pressure of the pipe.