JPH0160719B2 - - 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 correction device for an existing pipe to be repaired.

[Conventional technology]

In recent years, existing pipes buried underground such as gas pipes,
Various methods have been proposed for repairing pipes from the inside so that they can be regenerated from corrosion while still buried. In particular, with existing gas pipes buried underground, where cast iron pipes are connected using water-type joints or G-type joints, the sealing performance of the pipe joints has deteriorated and there is a need for repair. . That is,
Recently, city gas has replaced the coal gas that had been used for a long time as dry natural gas. However, in the case of dry natural gas, the sealing material dries and shrinks, creating voids, which deteriorates the sealing performance. Because it deteriorates and causes gas leakage,
There is a need to ensure the sealing performance of the pipe joint and to carry out repairs to prevent future deterioration of the sealing performance.

However, with existing gas pipes that have a medium diameter or small diameter, workers cannot enter the pipe and repair the inner surface of the pipe joint like they can with large diameter pipes, so repair work is difficult. Construction is difficult, and there is a need for a construction method in which workers are outside to repair the inner surface of pipe joints while they are buried.

[Problem to be solved by the invention]

Regarding this construction method, the present inventor has a means for filling and moving resin between at least a pair of front and rear pigs that are pulled by a towing cable and slide in airtight contact with the inner surface of the pipe. However, during this movement process, when the pipe joint is located between the front and rear pigs,
In the first stage, a low viscosity resin penetrant is applied between the joints.
We developed a repair method in which the material is impregnated under pressure into the sealing material, and in the second step, a high-viscosity resin putty is filled between the joints. According to this repair method, not only is it possible for an operator to repair the inner surface of the joint of a pipe while it is buried while the worker is outside, but also the sealing material dries and shrinks due to the penetrating agent that is impregnated under pressure into the sealing material. The sealing effect is enhanced by blocking the micropores, and the penetrating agent in the first stage acts as a lubricant for filling with the putty agent in the second stage. Between the pipe fittings Even though the surface is rough and uneven, the putty fills with good adhesion.
The double airtightness of the penetrant and putty agent achieves a repair with a high sealing effect. However, the structure for adjusting the filling pressure of the penetrant or putty agent is complicated.

The present invention is a repair device used to carry out the above-mentioned repair method, and when a pair of front and rear pigs is moved within an existing pipe, no filling pressure is applied to the resin, and the pig is temporarily stopped at the position of a pipe joint. When the speed is controlled to a low speed, the rear pig is elastically pulled forward and filling pressure is automatically applied to the resin, and when moving, the rear pig is designed to reliably follow the front pig. The object of the present invention is to provide a pipe joint repair device.

[Means to solve the problem]

In order to achieve this object, the present invention provides at least a pair of front and rear pigs inside an existing pipe that is pulled by a tow cable and slides in airtight contact with the inner surface of the pipe, and fills resin between the pigs. The pair of front and rear pigs are provided with suction grooves and filling grooves on the front side of the pig in a relationship that overlaps each other in the axial direction and at different positions in the circumferential direction. The rear pig is connected to the front pig by a connecting rope and is slidably attached to the rope, and is connected to the front pig via an elastic body such as a coil spring that exerts an elastic force in the direction of approaching each other. When the pipe is temporarily stopped at the pipe joint or the speed is controlled to a low speed, the rear pig moves toward the front pig due to the tensile traction force of the elastic body, and the resin interposed between the front and rear pigs applies filling pressure. The rear pig is characterized in that the rear pig is provided with a locking mechanism such as a one-way clutch that operates to prevent the connecting rope extending from the front pig from moving backward.

[Effect]

With the above configuration, when both the front and rear pigs move inside the pipe, no filling pressure is applied to the resin, and when the front pig is located at the pipe joint, the elastic body is stretched The traction force pressurizes the resin with the rear pig, and the locking mechanism locks the rear pig in the moving position.

〔Example〕

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

FIG. 1 shows the main body of a repair device according to the present invention, and in the figure, 1 is a front pig, and 2 is a rear pig. These pigs 1 and 2 are cylindrical with an outer diameter that corresponds to the inner diameter of the existing pipe 12 to be repaired and can slide in airtight contact with the inner surface of the existing pipe 12. On the outer periphery of the front pig 1, a suction groove 3 that opens on the tip side and a filling groove 4 that opens on the rear side overlap each other in the axial direction, in order to provide the function described later. ,
In addition, they are formed at different positions in the circumferential direction. In addition, the rear pig 2 has a slightly smaller outer diameter than the front pig 1 so as to reduce the sliding resistance when moving inside the pipe, and has a fin 2a on the outer periphery of the rear end to maintain airtightness. It stands out.

Regarding the pair of front and rear pigs 1 and 2, the front side pig 1 is connected with a tow rope 5 and a connecting rope 6 that also serve as length measurements in the forward and rearward directions of movement, and the connecting rope 6 that extends rearward. passes through the center of the rear pig 2 and allows the rear pig 2 to slide on the rope 6. In the present invention, the rear pig 2 is connected to the front pig 1 via the coil spring 7 so that an elastic force acts particularly in the direction in which the rear pig 2 approaches the front pig 1, and the tensile traction force of the coil spring 7 The structure is such that the rear pig 2 is pulled forward and filling pressure is applied to the resin (penetrating agent A or putty agent B described later) interposed between the two pigs 1 and 2, and the rear pig 2 is , for the rope 6 extending rearward from the front pig 1,
They are connected via a locking mechanism 8 such as a one-way clutch, and are configured not to move backward.

The repair device configured as described above is used in the following manner for repairing the inner surface of the existing pipe 12. The existing pipe 12 buried underground is a long cast iron pipe connected via pipe joints 13 and 14, such as water pipes, using a conventional piping method. In repairing the pipe joints 13 and 14 of the existing pipe 12, the present invention divides the existing pipe 12 into units of length suitable for repair, and repairs the plurality of pipe joints 13 and 14 interposed within that section. The pipe joint part 1
3, as is conventionally known, for example, a large diameter pipe 13a provided at one end of one pipe, and a large diameter pipe 13a provided at the other end 13.
b are butted against each other, a sealing material 15 usually called "hemp skin" is filled in the butt-fitting part, and the opening is sealed with a lead material 16.

The pigs 1 and 2 are introduced into the existing pipe 12 to be repaired through one of the openings thereof, with the space in which the pigs 1 and 2 face each other being filled with resin.
Here, in the first step, the resin is a low viscosity resin with hardening properties such as epoxy resin (100 cps ~
The pigs 1 and 2 are filled with a penetrating agent A of 1,000 cps) and a putty agent B of a high viscosity resin (for example, 100,000 cps to 300,000 cps) in the second stage. It is being moved inside the existing pipe 12 in the direction of arrow X.

Now, to explain the construction example specifically, the first
At this stage, as shown in FIGS. 1 and 2, penetrant A is filled between the pigs 1 and 2 and moved in the direction of arrow X. This movement is carried out by applying a predetermined negative pressure (for example, -0.5 kg/cm ² ) from the vacuum pump 20 into the existing pipe 12 on the front side in the moving direction, and by winding up the towing rope 5 with the winch 21 to move the front pig. By towing the front pig 1, the rear pig 2 is pulled through the coil spring 7 and locked by the locking mechanism 8, and the penetrating agent A is pulled together with the pigs 1 and 2. Move within the pipe. During this movement, the tensile traction force by the coil spring 7 does not work due to the traction resistance acting on the rear pig 2, and the filling pressure from the rear pig 2 is applied to the penetrant A filled between the front and rear pigs 1 and 2. Doesn't work.

During this movement process, the position of the pipe joint 13 or 14 is confirmed by judging from the piping diagram and pulling out (length measurement) of the towing rope 5, or by installing a video camera or magnetic sensor 18 on the towing rope 5, Based on this determination, when the front pig 1 moves to the position of the pipe joint 13 (or 14) as shown in FIG. 1, the movement of the front pig 1 is temporarily stopped or the speed is controlled to a low speed state at this position. .

Due to this speed control, the rear pig 2 is rapidly drawn toward the front pig 1 by the tensile traction force of the coil spring 7, and the distance between the two pigs 1 and 2 is narrowed. Filling pressure acts strongly on the filled penetrant A from the rear pig 2.
In this state, a predetermined pressure (for example, +0.5Kg/
cm ² ) of pressurized air pressurizes the rear pig 2 in the direction of arrow Y, thereby applying sufficient filling pressure to the penetrant A. As a result, as shown in FIG.
The liquid is penetrated into the sealing material 15 through the sealing material 15.

At this time, if there is an air leak in the pipe joint 13 (or 14), the penetrant A penetrates by pushing out the residual air in the sealing material 15.
In addition, if there is no air leakage, the residual air in the sealing material 15 will be trapped due to the pressurized penetration of the penetrant A, but in this case, the front pig 1 will have an opening facing forward. As shown in FIG. 4, the residual air in the sealing material 15 is pushed out from the gap 19 in the pipe circumferential direction by the pressurized infiltration of the penetrant A, and passes through the groove 3. After escaping into the front space of the front pig 1, the penetrating agent A is reliably replaced with air, and the penetrating agent A is deeply penetrated into the entire area of the sealing material 15.

When the impregnating action of the penetrant A on one pipe joint 13 (or 14) is finished, the pigs 1 and 2 are
The existing pipe 1 is
Move within 2. During this movement, the existing pipe 12 has a curved part, and there are various protrusions inside the pipe.
There may be steps caused by differences in pipe diameter, and the rear pig 2 may get caught on these, causing local traffic obstruction. 6, the rear pig 2 is linked to the front pig 1 via a locking mechanism 8 such as a one-way clutch, and is prevented from moving backward, so that the rear pig 2 can reliably follow and move with respect to the front pig 1.

In this way, when the impregnation action of the penetrant A in the first stage is completed, the second stage is to
A high viscosity resin putty agent B is filled in the opposing space,
Move this within the existing pipe 12 as described above, and place the pigs 1 and 2 against the pipe joint 13 (or 14).
When the pipe moves to the position shown in FIG. 1, the movement is temporarily stopped or at a low speed, and the space 19 between the pipe joints 13 is filled with putty. In this case, the interval = 1
There is a surplus of the previous penetrant A remaining in 9,
As shown in FIG. 4, suction force is applied from the front of the pig 1 through the grooves 3 formed on the outer periphery of the front pig 1, and filling pressure is applied to the putty agent B, so the grooves 3 The putty agent is substituted in the space 19 through
Filled.

In this construction method, the penetrating agent A that is impregnated under pressure in the first stage acts as a lubricant for the filling of the putty agent B in the second stage. Also, even if the surface between the pipe fittings is rough, the putty agent B has good adhesion, and the double airtightness of the penetrating agent A and putty agent B can be achieved. Repairs with a high sealing effect can be achieved depending on the nature of the repair (see Figure 5).

In addition, during the work of penetrating the sealing material 15 with the penetrant A and filling the gap 19 with the putty agent B, the pigs 1 and 2 need to pass through the elbow part of the existing pipe 12, etc. Since both the pigs 1 and 2 are connected by a coil spring 7, the device can be bent and has adaptability to curved portions of the existing pipe 12. Further, by appropriately selecting the tensile force of the coil spring 7, it is possible to omit the supply of pressurized air to the rear space of the rear pig 2 when filling the penetrating agent A or the putty agent B.

In the above embodiment, pneumatic pressure and suction are used to move the pig 1 and fill the resin, but it goes without saying that the magnitude of the pneumatic pressure can be adjusted depending on the situation. Moreover, the suction action may be omitted.

〔Effect of the invention〕

As described in detail above, the present invention is to fill a pair of front and rear pigs towed by a tow rope with resin (penetrant or putty agent), pass this into an existing pipe, and place the resin at the pipe joint of the existing pipe. When applying filling pressure to repair the pipe joint, the rear pig is connected to the front pig, which has a replacement function, by a linking rope, and is slidably attached to the rope, so that it is elastically pulled by a coil spring. , when the movement of the front pig is temporarily stopped or controlled to a low speed at the pipe joint, filling pressure is automatically applied to the resin, so even a simple device can easily penetrate the resin into the pipe joint of the existing pipe. In addition to being able to carry out the filling action, the rear pig is restricted from retreating backwards, so even if there is a traffic obstruction when moving the pig, the rear pig can reliably follow the front pig. Furthermore, when the amount of resin decreases due to the progress of resin penetration and filling work, the rear pigs are sequentially moved to the front side in response to the amount of decrease and are held at the moving position. The inconvenience of having a gap in the resin filling space can also be eliminated, and the resin can penetrate into the pipe joint and the filling action can be carried out smoothly and reliably.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway longitudinal side view of an embodiment of the present invention, FIG. 2 is a perspective view of the entire longitudinal section, FIGS. 3 to 5 are action explanatory views, and FIG. is a perspective view of the front pig. 1... Front pig, 2... Rear pig, 3, 4...
Groove, 5... Towing rope, 6... Connecting rope, 7
. . . Coil spring, 8 . . . Locking mechanism, 12 .
...lead material, 18...sensor, 19...between, A...
Penetrant, B... putty agent.

Claims (1)

[Scope of Claims] 1. A means for providing at least a pair of front and rear pigs inside an existing pipe, which are pulled by a tow cable and slidingly in contact with the inner surface of the pipe, and filling resin between the pigs and moving the pigs. The pair of front and rear pigs is provided with a suction groove and a filling groove on the front pig in a relationship that overlaps each other in the axial direction and at different positions in the circumferential direction. The rear pig is connected to the pig by a connecting rope and is slidably attached to the rope.The rear pig is connected to the pig through an elastic body such as a coil spring that exerts an elastic force in the direction of approaching each other, and the front pig is connected to the pipe joint. When the speed is temporarily stopped or the speed is controlled to a low speed at the position of A pipe joint repair device for an existing pipe, characterized in that the side pig is provided with a locking mechanism such as a one-way clutch that operates to prevent the connecting rope extending from the front pig from retreating.