JPH0156314B2 - - Google Patents

Description

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

[Conventional technology]

In recent years, various methods have been proposed for repairing existing pipes such as gas pipes, water pipes, etc. buried underground, from the inside so as to regenerate and reinforce the pipes against corrosion and the like while the pipes are buried. In particular, with existing gas pipes buried underground, cast iron pipes are fitted with water type fittings or G
In pipes connected by type joints, the sealing properties of the pipe joints have deteriorated, requiring repair. In other words, recently, city gas has become dry natural gas instead of the coal gas that had been used for a long time. Deterioration of sealing performance was not a particular problem because it penetrated into the sealing material called "hemp skin," but in the case of dry natural gas, the sealing material dries and shrinks, creating voids and causing the seal to deteriorate. Since this deteriorates the sealing performance of the pipe joint and causes gas leakage, it is necessary to ensure the sealing performance of the pipe joint and perform repairs to prevent seal deterioration in the future.

Therefore, it has been proposed that a filling chamber formed in the pig is filled with resin, and when the pig moves to the pipe joint, the filling pressure applied to the resin is used to fill and repair the pipe joint. .

[Problem to be solved by the invention]

However, since branch pipes are connected to the existing pipes at various places, there is a problem that when the pig passes through the branch pipe parts, the resin infiltrates into the branch pipe parts and blocks them.

The present invention has been made based on the above circumstances, and when the end of the branch pipe is left open and the pig passes through the communicating part of the branch pipe, the positive pressure applied to the pig enters the branch pipe, causing pressure. This decrease is used to detect this branch pipe communication point, and while the pig passes through the branch pipe communication point, at least the filling pressure into the resin is reduced to prevent resin from entering the branch pipe. The present invention aims to provide a pipe joint repair device for existing pipes that can repair existing pipes.

[Means to solve the problem]

In order to achieve this object, the present invention forms two chambers in the front and back in a pig that slides in airtight contact with the inner surface of the existing pipe, the front chamber is used as a pressure fluctuation chamber, and the rear chamber is used as a resin filling chamber. At the same time, the intermediate pig that partitions into two chambers, front and rear, has a resin filling groove that opens on the rear side in the moving direction, and a substitute material escape groove that extends to the vicinity of the front end, with opposite ends in the axial direction. The resin filling chamber is provided with a flexible bag that can expand its volume, and the resin filling chamber is provided with a flexible bag that can expand its volume. The resin filling chamber is configured to apply filling pressure to the resin in the resin filling chamber, and the pressure fluctuation chamber and the pressurizing part of the resin filling chamber are communicated through a communication passage to apply positive pressure to the pressure fluctuation chamber. It is characterized by having been configured.

[Effect]

With the above configuration, when the pressure fluctuation chamber of the pig passes through the branch pipe, the pressure in the pressure fluctuation chamber enters the branch pipe, the pressure in the pressurized part of the resin filling chamber decreases, and the resin enters the branch pipe. It disappears. .

〔Example〕

Hereinafter, one embodiment of the present invention will be specifically described with reference to FIGS. 1 to 8.

In the figure, reference numeral 1 denotes a cylindrical pig, and a tow rope 2 passes through the center of the inside, and is fixed to support disks 3, 3 provided at the front and rear ends of the pig 1. The pig 1 has three pig parts 4, 5 and 6, front, middle and rear, which are continuous by a small-diameter body part 7, 8 to form an integral structure. A first chamber formed between the front pig part 4 and the intermediate pig part 5 is used as a pressure fluctuation chamber 11, and a second chamber is formed in the vicinity of the body by passing through the intermediate pig part 5. It is provided with a communication path 9 communicating with.

Further, a positive pressure supply pipe 12 is opened to communicate with a second chamber that passes through the rear pig part 6 and is formed between the pig parts 5 and 6. It is composed of a flexible hose, extends rearward in the moving direction of the pig 1, and is connected to the compressor 13. An inflatable cylindrical flexible bag 14 made of a rubber membrane or the like is disposed concentrically between the pig parts 5 and 6, and partitions the second chamber into the inside and outside. The positive pressure supply pipe 12 is opened on the inside of the housing. The inside of the flexible bag 14 is used as a pressurizing chamber 15, and the outside is used as a resin filling chamber 16. Therefore, the pressurized chamber 15 is communicated with the first chamber 11 via the communication path 9 described above.

As shown in detail in FIG. 2, the intermediate pig portion 5 has, on its outer periphery, a resin filling groove 17 that opens toward the rear in the direction of movement and extends to the vicinity of the front end, with the intention of providing the function described later. In the axial direction, the opposing ends of the substituted substance escape groove 18 overlap, and in the circumferential direction, both the grooves 17 and 1
8 are formed at different positions so that they do not communicate with each other.

The substituent escape groove 18 is communicated with a passage 18a that passes through the inside of the pig 1 and opens to the front of the pig 1. This passage 18a has a hose 1
A vacuum pump 10 is connected via Oa.

In addition, as shown in Fig. 3, in front of pig 1,
Magnetic sensor block 1 is separated by a predetermined distance.
9 is fixed to the traction rope 2. This magnetic sensor block 19 is provided with a plurality of magnetic sensors 20 at divided positions in the circumferential direction.
The signal sending cable 21 extends forward. The towing rope 2 is provided with a scale for measuring its length, and is wound around winches 22 and 23 at the front and back, respectively.

The repair device having such a configuration is used for repairing the inner surface of the existing pipe A in the following manner. Here, the existing pipe A buried underground is a long cast iron pipe connected via pipe joints B and C, such as water type pipes, using a conventional piping system. This existing pipe A
When repairing the pipe joints B and C, in the present invention,
Existing pipe A is divided into length units suitable for repair. Then, a plurality of pipe joints B and C interposed within this section are repaired in a series of repair processes.
For example, the large-diameter part B ₁ provided at the end of one existing pipe A abuts the pipe end B ₂ of the other existing pipe A, and the butt-fitting part is usually called "hemp skin". It has a connection structure in which a sealing material D is filled in and the opening is sealed with a lead material E, and a slight gap F is left at the abutting ends. In addition, the pipe joint part C is fitted with a large diameter pipe joint member _C1 so as to cover the ends of the existing pipes A that face each other, and the sealing material D is packed in the fitting part with the existing pipe A. It has a connection structure in which the opening is sealed with a lead material E, and a slight gap F is left at the abutting ends.

The pig 1 is introduced into the existing pipe A to be repaired through one opening. In the present invention, the resin filling chamber 16 is filled with a thermosetting low-viscosity resin such as an epoxy resin (for example,
The pipe is filled with a penetrating agent X (10 cps to 1000 cps) or a filling putty Y made of a high viscosity resin (for example 10000 to 300000 cps), and is transported along with the pig 1 inside the existing pipe A by being pulled by a towing rope 2.

In the first stage, as shown in FIG. 4, the filling chamber 16 is filled with the penetrant X and is moved in the direction of the arrow. This movement is performed by winding the tow rope 2 in with the winch 22. 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. Based on the reaction of this sensor 20 confirming the position of the pipe joint B (or C), the pig 1 moves to the pipe joint B (or C).
(or C), the movement of the pig 1 is temporarily stopped or slowed down at this position. First, at the stage where the intermediate pig portion 5 passes through the pipe joint B (at the position where the pressure fluctuation chamber 11 passes through the pipe joint B) (see Fig. 4), negative pressure is applied to the groove 18 by the action of the vacuum pump 10. When this is applied, a negative pressure is applied to the gap F and the sealing material D of the pipe joint B, and the air is sucked together with the dust present therein. In this state, since the grooves 17 and 18 are opposed to the gap F on the outer periphery of the intermediate pig portion 5, the passage 18a is connected to the gap F and the grooves 17 and 18 in the filling chamber 16.
8, the communication is established. If air remains in the filling chamber 16, this is also removed by suction with negative pressure. The osmotic agent
By applying positive pressure from the compressor 13 through the compressor 13, the flexible bag 14 receives filling pressure due to volume expansion, and is supplied to the gap F via the groove 17, and the air in the gap F is filled with negative pressure. In the process of being drawn by the vacuum pump 10 through the passage 18a, the sealing material D is penetrated. In this case, in the pressurizing chamber 15,
For example, pressurized air of +0.5 kg/cm ² may be supplied.

At this time, if there is an air leak in the pipe joint B (or C), the penetrant X will penetrate by pushing out the residual air in the sealing material D, and
If there is no air leakage, it is expected that the residual air in the sealing material D will be trapped due to pressurized penetration of the penetrant The negative pressure suction force 10 acts on the gap F and the sealing material D through the grooves 18. Therefore, the residual air in the sealing material D is pushed out by the pressurized infiltration of the penetrant From F in the pipe circumferential direction, groove 18 and passage 1
Because it escapes to the vacuum pump 10 side through 8a,
The replacement action between air and penetrant X is reliably carried out,
The penetrant X is deeply penetrated into the entire area of the sealing material D.

When the impregnating effect of the penetrant A on the sealing material D for one pipe joint part B (or C) is completed, the pig 1 is moved within the existing pipe A again by being pulled by the pulling rope 2.

A case where the pig 1 passes through a location where a branch pipe G is opened to communicate with the existing pipe A as shown in FIG. 6 in the course of this movement will be explained. This branch pipe G
The terminal is opened to the atmosphere prior to this operation. Therefore, when the pressure fluctuation chamber 11 corresponds to the communication opening of the branch pipe G while the pig 1 is moving, the pressurized air given by the compressor 13 is transferred from the pressurization chamber 15 to the pressure fluctuation chamber via the communication path 9. 11 and further passes through the branch pipe G to the above-mentioned gap F,
Residual air in the sealing material D causes the grooves 18 and passages 1
The air flow rate is much higher than the air flow rate when escaping to the vacuum pump 10 side through 8a. Shrink. Therefore, the resin in the filling chamber 16 is pulled toward the flexible bag 14. And the pressure fluctuation chamber 11 is connected to the branch pipe G.
When the opening of the branch pipe G corresponds to the filling chamber 16 position, the outer periphery of the pressure fluctuation chamber 11 is closed by the inner wall of the existing pipe A, so the flexible bag 14
starts to expand gradually, but until the pig 1 passes through the communication opening of the branch pipe G, the resin is not pushed out into the branch pipe G, and the resin does not enter into the branch pipe G. The time lag for this can be easily achieved by setting the pulling speed of the pulling rope 2, the supply pressure of compressed air by the compressor 13, etc.

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

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. The pressure sensor may also be provided on the ground near the compressor on an extension of the hose 12.

In this way, the resin in the filling chamber 16 is prevented from entering the branch pipe G while passing through the communication opening of the branch pipe G.

Through such a process, the penetrant X permeates the sealing material D at each pipe joint A.
During this time, the amount of residual penetrant X decreases. However, it is the expansion of the flexible bag 14 that can substantially apply filling pressure to the resin until the final stage.

In this way, when the impregnation action of the penetrant X in the first stage is completed, the filling chamber 1 is
6 is filled with a high-viscosity resin putty Y, and moved within the existing pipe A in the same manner as in the first step described above, so that the pig 1 is in the specified position with respect to the pipe fitting B (or C). When moving, the movement is temporarily stopped or at a low speed, and the putty agent Y is pressurized and filled (see FIG. 7). In this case, the surplus of the penetrant X remains in the gap F, but it is sucked and discharged to the vacuum pump 10 side via the groove 18, and
Since a filling pressure is applied to the putty agent Y, instead of being pulled, the putty agent Y is filled through the groove 17 and replacement is performed.

Moreover, the surplus of the penetrating agent Filling can be achieved reliably, and even if the inner surface of the gap F of the pipe joint B (or C) is rough with unevenness, the putty Y has good adhesion and has both an airtight effect and a gap sealing effect. can be increased.

Further, in this embodiment, the pig 1 is composed of an integral structure having two chambers, including a front pig part 4, an intermediate pig part 5, and a rear pig part 6.
Of course, they may be configured separately and connected to each other.

Also, a hose 10a provided through the pig 1
may simply be opened in front of the pig 1 without performing negative pressure suction.

〔Effect of the invention〕

As described in detail above, when passing a pig into an existing pipe, the present invention first removes substitute materials from the pressure fluctuation chamber from the pressure fluctuation chamber and the sealing material in the pipe joint, and immediately after that, resin By filling the pipe with the required filling pressure using an intermediate pig, the pipe joint can be successively repaired from the inside of the pipe by moving the pig, and the pipe joint can be reliably and completely sealed. In addition, in the branch pipe communication section, a large amount of pressurized air from the pressure fluctuation chamber leaks into the branch pipe, making it possible to confirm the branch pipe position and causing the flexible bag to contract, allowing the pig to pass through the branch pipe position. During this time, resin can be prevented from entering the branch pipe, thereby preventing clogging of the branch pipe.

[Brief explanation of drawings]

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 stage.
FIGS. 7 and 8 are partially enlarged vertical cross-sectional views illustrating the state of penetration of the penetrant in the second stage. 1...Pig, 2...Tow rope, 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, 1
5... Pressurization chamber, 16... Filling chamber, 17, 18...
Groove, 18a... Passage, 19... Block, 20
...Sensor, 21...Cable, 22, 23...
Winch, A...Existing pipe, B...Pipe joint, B ₁
...Large diameter section, _B2 ...Pipe end, C...Pipe joint section,
D...Sealing material, E...Lead material, F...Void, G...
... Branch pipe, C ₁ ... Pipe joint member.

Claims (1)

[Scope of Claims] 1. A pig that slides in airtight contact with the inner surface of an existing pipe has two chambers in the front and rear, the front chamber being a pressure fluctuation chamber and the rear chamber being a resin filling chamber. The intermediate pig, which is partitioned into two front and rear chambers, has a resin filling groove that opens toward the rear in the direction of movement, and a substituent escape groove that extends to the vicinity of the front end, with their opposing ends overlapping in the axial direction. The resin filling chamber is provided with a flexible bag that can expand its volume, and positive pressure is applied to the flexible bag. The pressure fluctuation chamber is configured to be able to apply filling pressure to the resin in the resin filling chamber, and the pressure fluctuation chamber and the pressurizing part of the resin filling chamber are communicated through a communication passage to apply positive pressure to the pressure fluctuation chamber. A pipe joint repair device for existing pipes, which is characterized by: