JPH0333959B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a method for filling and sealing a pipe joint interposed in a pipe with a resin while keeping an existing pipe such as a gas pipe buried underground in the laid state. This invention relates to a repair device for existing pipes.

[Conventional technology]

Existing piping such as this type of gas pipeline is generally a conduit called a main pipe or branch pipe underground under the road, and a supply pipe that leads gas, etc. to each demand destination from this conduit line. Many of them have many branches.

The above-mentioned conduit (main pipe) is generally a long cast iron pipe connected with a water-type joint and installed under the road. Due to changes in the ground over time, the joint condition may change and gaps may appear in the joint, or the constituent materials of the joint may deteriorate, causing gas leaks. For the purpose of maintenance, a method of repairing the seal by filling the space between the inside of the pipe and the joint with resin while the pipe joints of existing pipes are buried is being put into practical use.

Conventionally, as a means of repairing this, in order to ensure that the space between the pipe joints is filled with resin, a method has been used to displace and fill the resin while discharging the air stagnant between the pipe joints to the outside. For example, JP-A-59-49870, JP-A-59-151690, etc. have proposed the following.

[Problem to be solved by the invention]

By the way, the existing piping to be repaired has a large number of pipe joints placed at predetermined intervals on the pipe, and some of these joints are leaking and others are not. There is a mixture of cases where no leakage phenomenon has occurred.

The conventional prior art described above targets all the pipe fittings on the pipe without distinguishing whether or not leakage is occurring among the large number of pipe fittings on the pipe. The repair is carried out by replacing and filling the space between the joints with resin.

As a result, resin is wasted and replaced even in pipe joints that do not require repair, resulting in the problem that the amount of resin required for repair is wasted and the cost of repair becomes high.

The present invention makes it possible to carry out the repair by selecting whether or not the repair is necessary in order to avoid the above-mentioned unnecessary waste of resin when sealing and repairing the pipe joint part of the existing pipe. It is an object of the present invention to provide an existing pipe repair device that can confirm the location of branch points of supply pipes and also perform airtightness tests on the branch supply pipes and pipe joints after repair.

[Means to solve the problem]

In order to achieve this object, the present invention involves inserting a leading pig, which is pulled by a tow cable and moving inside the pipe, and a replacement pig in a connected manner into an existing pipe with a required space between them, and The rear displacement pig has a groove for resin filling and an air escape passage along its outer circumference in the longitudinal direction, and a resin pumping means is communicated with the groove for resin filling, and the displacement pig is replaced during the movement inside the pipe. When the pig is positioned corresponding to the pipe joint of the existing pipe, the resin is supplied from the resin pumping means and the resin is replaced with the accumulated air between the joints through the filling groove and the air escape passage. It has a structure that can be filled with air, and is equipped with means for supplying air at a required pressure into the opposing spaces between the front and rear leading pigs and the replacement pig, and means for detecting changes in air pressure within the opposing spaces. It is characterized by becoming.

[Effect]

According to the above configuration, when the lead pig and the replacement pig are pulled and moved inside the pipe by the towing rope, if a leakage phenomenon occurs at the pipe joint interposed in the conduit of the existing pipe, the pipe When the joint is located in the space facing the leading pig and the replacement pig, the air pressure supplied into the facing space leaks from the leakage point of the pipe joint, causing the internal pressure in the facing space to drop. By detecting a drop in internal pressure using a detection means, it is possible to know whether a leak phenomenon is occurring at a pipe joint interposed in the middle of an existing pipe, and It is possible to perform repairs by selecting whether or not repairs are necessary for the joint.

In addition, during the movement process, when the opposing space between the leading pig and the replacement pig passes through a branch part of the supply pipe branched by the existing pipe, for example, if the socket provided at the end of the supply pipe is left open, Since the air supplied under pressure into the opposing space is discharged to the outside through the supply pipe, it is also possible to confirm the location of the branch point of the supply pipe.

At this time, if you close the cap on the supply pipe, if there is a leak in the supply pipe, the internal pressure in the space facing the leading pig and the replacement pig will be By detecting this drop in internal pressure, it is possible to check whether or not the supply pipe at the branch point requires repair. You can also check the airtightness test to see if the repair has been completed, and similarly, you can also check the airtightness test for the pipe joint after the repair is completed.

〔Example〕

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

First, in FIG. 1, reference numeral A indicates an existing pipe to be repaired, and inside the existing pipe A, there is a leading pig 14 on the front side that moves inside the pipe by being pulled by a towing cable 12.
A replacement pig 1 on the rear side following this is connected and inserted with a required facing space between them.

As shown in FIGS. 2 and 3, the rear replacement pig 1 has a cylindrical pig body that includes a plurality of hard rubber constituent pieces 1a and a plurality of soft rubber constituent pieces 1b. , which are arranged alternately in tandem and connected one after the other. On the outer periphery of the replacement pig 1, a plurality of (two in the illustrated embodiment) resin filling grooves 2 and 3 are formed which are located above and below the pig and extend in the longitudinal direction. In the illustrated embodiment, a pressure-resistant hose 4 for pressurizing and supplying resin is connected to the rear of the displacement pig 1 through a resin supply passage 5 communicating with the groove 3 for resin filling on the lower side. On the other hand, the upper resin filling concave groove 2 is provided with air escape passages 6 and 7 that communicate with its front and rear ends, and an air escape passage that opens to the rear side. 6 is provided with an on-off valve 9 in a conduit 8 communicating therewith, and an air escape passage 7 opened to the front side is provided with a leading pig 14, which will be described later, passed through.
Its front end communicates with a conduit 10 opened in front of the leading pig 14.

The replacement pig 1 has a magnetic sensor 11 embedded in the center corresponding to the position where the resin filling grooves 2 and 3 are formed, and the output signal can be taken out to the rear. It is set as.

A traction cable 12 is inserted through the center of the replacement pig 1, and the traction cable 12 is connected to a support plate 13 embedded within the replacement pig 1 via a knot 12a. This towing line 12 passes through the leading pig 14 placed in front and extends forward inside the existing pipe A, and by operating a winch or the like, pulls the leading pig 14, followed by the replacement pig 1. It is doing the work that will be done.

In addition, the displacement pig 1 is provided with a pressurized air supply pipe 15 that penetrates the displacement pig 1 in the front and rear directions as a means for supplying air under pressure into the space facing the leading pig 14 on the front side. The front end of the pipe 15 is opened in the space where the leading pig 14 and the replacement pig 1 face each other, and air at a predetermined pressure, which is pumped from the rear of the replacement pig 1, is passed through the pressurized air supply pipe 15 to It is designed so that it can be supplied into the opposing space. Although not shown here, a means for detecting changes in air pressure in the opposing space between the leading pig 14 and the replacement pig 1 may be used, for example, at an appropriate location on the pipe line of the pressurized air supply pipe 15 or in the opposing space. A sensor (not shown) is provided at an appropriate location inside.

Like the replacement pig 1, the leading pig 14 has a structure in which hard rubber constituent pieces 14a and soft rubber constituent pieces 14b are alternately arranged and connected in tandem, and on the outer periphery of the soft rubber constituent pieces 14b, Existing pipe A
Fins 16 are formed to ensure airtightness with the inner wall of the housing. Reference numeral 17 in the figure indicates support plates arranged on the front and rear end surfaces and inside of the lead pig 14 in order to prevent the lead pig 14 from extending in the longitudinal direction. 18, it is connected by a nut 19. Further, a sensor 20 for detecting the amount of resin is provided on the front end surface of the leading pig 14.

Next, repair work for the existing pipe A according to the embodiment configured as described above will be explained.

First, when both pigs 14, 1 are introduced into the existing pipe A, a small amount of resin is filled in front of the leading pig 14 in order to improve the sliding on the inner wall of the pipe.
In addition, when moving both pigs 14, 1 along the inside of the pipe by pulling the tow rope 12, the pressurized air supply pipe 1
5, air at a predetermined pressure is supplied from a compressor, an air cylinder, or the like.

In this state, indexing measure 12 allows the first pig to
4 and the replacement pig 1 are pulled and moved along the inside of the pipe. During this moving process, the leading pig 14 and the replacement pig 1 sequentially change the position of the pipe joint part B interposed in the conduit of the existing pipe A. Proceed as you pass.

At this time, if a leakage phenomenon occurs in the pipe joint part B etc. passing through, the pipe joint part B
and the displacement pig 1, the air pressure supplied into the opposing space through the pressurized air supply pipe 15 leaks from the leakage point of the pipe joint B, so that the air pressure in the opposing space is The internal pressure changes as it decreases. By detecting this decrease in internal pressure with a sensor (means for detecting a change in air pressure) provided at an appropriate location on the pipe path of the pressurized air supply pipe 15 or at an appropriate location in the opposing space, the existing pipe A It is possible to know whether or not a leakage phenomenon is occurring in the pipe joint part B interposed in the middle of the pipe, and to determine whether or not repair is necessary for the pipe joint part B.
It becomes possible to detect and select unnecessary items.

Then, when repair is required for the pipe joint B, the replacement pig 1
When the position corresponding to the replacement pig 1 is reached, the magnetic sensor 11 is activated and the signal stops the towing and movement by the tow rope 12, and the grooves 2 and 3 for resin filling formed on the outer periphery of the replacement pig 1 are inserted into the pipe joint. The state corresponds to the inner space C of part B. In this state, when the resin is pumped through the pressure hose 4, the resin enters one of the resin filling grooves 3 through the resin supply passage 5, and then flows into the inner space C of the pipe joint B in an annular shape. It flows and fills the space C. At this time, the air remaining in the inner space C of the pipe joint B is discharged to the pipes 8 and 10 through the air escape passages 6 and 7 that communicate with the front and rear ends of the other resin filling groove 2. The resin is then filled while replacing the air.

In this case, in order to ensure that the inner space C of the pipe joint B is filled with resin reliably and sufficiently, a slight excess of resin is pumped. This surplus pressure-fed resin flows out through the air escape passages 6 and 7 to the pipe lines 8 and 10 communicating therewith. Therefore, as in the illustrated embodiment, if an on-off valve 9 is provided in the conduit 8 that communicates with the rear side thereof, for example, the lubricating resin D interposed in front of the leading pig 14 decreases due to movement within the pipe. If the resin becomes insufficient, the sensor 20 detects this and closes the on-off valve 9 based on the signal. This cuts off the airflow to the pipe 8 and removes the excess resin along with the airflow. It is discharged in front of the leading pig 14 via the pipe line 10 and replenished as lubricating resin D.

Further, in this embodiment, when the opposing space between the leading pig 14 and the replacement pig 1 passes through the branch part F of the supply pipe E branched from the existing pipe A, the cock G provided in the supply pipe E is When it is left open, the compressed air supplied into the opposing space is discharged to the outside through the supply pipe E, making it possible to confirm the location of the branch point of the supply pipe E. Also, at this time, the supply pipe E
When the pot G prepared for this is closed, if there is a leak in the supply pipe E, the internal pressure in the opposing space between the leading pig 14 and the replacement pig 1 will decrease, as in the case where a leak in the pipe joint B is detected. Therefore, this decrease in internal pressure is detected by a sensor (means for detecting changes in air pressure), and it can also be determined whether or not the supply pipe E branched at this point requires repair. If the inner surface of the supply pipe E has been repaired in advance, it is possible to conduct an airtightness test to determine whether the repair has been completed completely, and similarly, an airtightness test of the pipe joint after the repair is completed. Can be confirmed.

[Effects of the Invention] As explained above, according to the repair device of the present invention, in the space facing the leading pig 14 on the front side, which is pulled and moved into the existing pipe A, and the replacement pig 1 on the rear side. , a means for supplying air at a required pressure and a means for detecting a change in air pressure in the opposing space are provided, and during the moving process in the pipe, the change in air pressure in the opposing space causes a change in the air pressure in the existing pipe A. It is possible to check whether or not a leakage phenomenon has occurred in the interposed pipe joint part B, etc., and it is possible to detect whether or not repair of the pipe joint part is necessary, select it, and carry out the repair.

In addition, during the above-mentioned intra-pipe movement process, if necessary, the change in internal pressure in the opposing space between the leading pig 14 and the replacement pig 1 is used to locate the branch point of the supply pipe E branched from the pipe line of the existing pipe A. It is also possible to confirm the location of the branched supply pipes and the pipe joints after repair, and the airtightness test can also be carried out.

[Brief explanation of the drawing]

Fig. 1 is a schematic longitudinal sectional side view of the entire repair device showing one embodiment of the present invention, Fig. 2 is a longitudinal sectional side view of the main parts thereof, and Fig. 3 is a side view taken along line A-A in Fig. 2. be. 1... Replacement pig, 2, 3... Groove for resin filling,
4...Pressure hose, 5...Resin supply passage, 6,7
... Air escape passage, 8 ... Pipeline, 9 ... Opening/closing valve, 10 ... Pipeline, 11 ... Magnetic sensor, 12
... Traction rope, 13 ... Support plate, 14 ... Top pig, 15 ... Pressurized air supply pipe, A ... Existing pipe, B
...Pipe joint part, C...Inner space, C...Lubricating resin, E...Supply pipe, F...Branch part, G...Kotuku.

Claims (1)

[Scope of Claims] 1. Inserting a leading pig, which is pulled by a tow rope and moving through the pipe, and a replacement pig in a connected manner into an existing pipe with a required space between them, and replacing the rear side. The pig has a groove for resin filling and an air escape passage along its outer periphery in the longitudinal direction, and a resin pressure feeding means is communicated with the groove for resin filling, so that the replacement pig can be inserted into the existing pipe during the movement inside the pipe. When positioned corresponding to the pipe joint, the resin is supplied from the resin pumping means to fill the space between the joints by replacing the accumulated air with the resin through the filling groove and the air escape passage. In addition, it is characterized by comprising means for pumping and supplying air at a required pressure into the opposing spaces between the front and rear leading pigs and the replacement pigs, and means for detecting changes in air pressure within the opposing spaces. Equipment for repairing existing pipes.