JPH0155717B2 - - 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 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 the pipes from corrosion and the like while they are 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. .
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, causing voids. Since the sealing performance deteriorates and causes gas leakage, it is necessary to ensure the sealing performance of the pipe joint.
Since then, it has become necessary to carry out repairs to prevent deterioration of sealing properties.

However, for 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 for large diameter pipes, so it is difficult to carry out repair work. Therefore, 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 provided a means for moving the resin into the existing pipe through a pig that is pulled by a towing cable and slides in airtight contact with the inner surface of the pipe, and this movement process When the pig passes through the pipe joint, in the first step, a low-viscosity resin penetrant is impregnated into the sealing material from between the joints under pressure.
In the second step, we developed a repair method that involves filling the space between the joints with a high-viscosity resin putty. 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. Even if the surface between the pipe joints is rough and uneven, the putty fills with good adhesion, and the double airtightness of the penetrating agent and the putty allows for highly effective repairs. However, the resin pressurizing means used to infiltrate or fill the pipe joint with resin is complicated.

The present invention is a repair device used to carry out the above-mentioned repair method, in which a penetrating agent or a resin such as a putty material moved by a pair of front and rear pigs can reliably penetrate into the sealing material of a pipe joint. It is an object of the present invention to provide a pipe joint repair device for an existing pipe that is devised so that it can be filled with putty.

[Means to solve the problem]

In order to achieve this object, the present invention has a main pig that is pulled by a towing rope and slides in airtight contact with the inner surface of the pipe inside the existing pipe. The main pig has means for moving the resin under pressure by interposing a resin between it and a movable pig that is slidably provided on the rope. The escape groove that opens to the rear and the resin distribution groove that opens to the front are shifted in the circumferential direction so that they do not communicate with each other, and the opposing ends of both grooves are aligned in the direction of movement. The pipes are formed so as to overlap each other, and when the main pig passes through the pipe joint, the main pig penetrates into and fills the sealing material of the pipe joint.

[Effect]

With the above configuration, the resin interposed on the front side of the main pig is pressurized by the movement of both pigs, and when the main pig is located at the pipe joint, the resin infiltrates or fills the pipe joint.

〔Example〕

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

In the figure, 1 is a pig which is the main body of the repair apparatus according to the present invention, and 2 is a movable pig placed in front of the pig 1 at a predetermined distance from each other.
These pigs 1 and 2 are cylindrical in shape and have an outer diameter that corresponds to the inner diameter of the existing pipe 12 to be repaired so that they can slide in airtight contact with the inner surface of the existing pipe. On the outer periphery of the side main pig 1, there are resin filling grooves 3 that open on the front side in the moving direction and grooves 4 for substitute material escape that open on the rear side in the axial direction. The grooves 3 and 4 are formed so that their opposing ends overlap each other, and the positions of the grooves 3 and 4 are changed so that they do not communicate with each other in the circumferential direction (see FIG. 6). The main pig 1 above has the following:
Tow ropes 5 and 6 that also serve as length measurements are connected in the forward and backward directions of movement, and the tow rope 5 extending forward passes through the center of the movable pig 2 and is movable with respect to the tow rope 5. Pig 2 is slidable. This movable pig 2 utilizes the resistance generated by sliding contact with the inner surface of the pipe when moving inside the pipe to apply the required amount to the resin (penetrating agent A or putty agent B described later) interposed between the two pigs 1 and 2. It applies pressing force.

The repair device having such a configuration 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 conventional piping construction methods. 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 well known in the art, for example, a large diameter portion 13a provided at the end of one pipe is connected to the end 13 of the other pipe.
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 ~
Penetrant A (1,000 cps) is filled with a putty agent B of high viscosity resin (for example, 100,000 cps to 300,000 cps) in the second stage, and the existing pipe 1 is pulled by a towing rope 5.
2 in the direction of arrow X. During this movement, pressurized air may be sent into the existing pipe 12 behind the main pig 1, and the pig may be moved by a combination of the traction action by the rope 5 and the pneumatic action.
In FIG. 2, 21 is a winch that winds up the tow rope 5, and 22 is a compressor that supplies pressurized air.

Next, to explain a construction example in detail, in the first stage, as shown in Figures 1 and 2, penetrant A is filled between pigs 1 and 2 and moved in the direction of arrow X. . During this movement, the movable pig 2 generates movement resistance due to sliding contact with the inner surface of the tube, so a backward pressing force acts on the penetrant A.
On the other hand, the penetrant A is pushed from the rear toward the front by the main pig 1, so that high pressure is generated on the rear side of the penetrant A.

When the pig 1 moves within the pipe to the position of the pipe joint part 13 (or 14) as shown in FIG. , the penetrant A passes through the groove 3 to the pipe joint 13.
The sealing material 1 is fed under pressure through the joint part 19.
It is penetrated into 5.

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 outer periphery of the pig 1 will be There is a groove 4 that opens, and the residual air in the sealing material 15 is pushed out by the pressurized infiltration of the penetrant A, as shown in FIG. Since the penetrating agent A is released into the rear space of the pig 1, the substitution effect between the air and the penetrating agent A is reliably performed, and the penetrating agent A is deeply penetrated into the entire area of the sealing material 15. During this infiltration, if the movement of the main pig 1 is temporarily stopped or the speed is controlled to a low speed state, the infiltration action can be performed more reliably.

When the impregnating action of the penetrant A on one pipe joint 13 (or 14) is finished, the pigs 1 and 2 are
is moved within the existing pipe 12 by being pulled by the aforementioned rope 5.

When the impregnating action of the penetrant A in the first stage is completed in this way, the second stage is to fill the opposing space between the main pig 1 and the movable pig 2 with a high-viscosity resin putty B. When the main pig 1 moves within the existing pipe 12 as described above and moves to the position shown in Figure 1 with respect to the pipe joint 13 (or 14), the movement is temporarily stopped or at a low speed and the pipe is moved. Fill the space 19 between the joints with putty agent B. In this case, a surplus of the previous penetrant A remains in the space 19, but as shown in FIG. Since filling pressure is applied to the agent B, the putty agent B is substituted and filled into the space 19 via the groove 3.

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. Even if the surface between the pipe joint part 13 (or 14) is rough, the putty agent B has good adhesion, and the penetration agent A and the putty agent The double airtightness of B allows a highly effective repair to be achieved (see Figure 5). Even when the movable pig 2 is omitted, the resin is pressurized by the movement of the main pig 1, and the pig 1 causes the resin to permeate or fill the pipe joint.

In addition, during the above construction, if a branch pipe branches from the existing pipe 12, the tip side of this branch pipe is closed, or pressurized air is sent from the tip side to the branch pipe. It is possible to prevent the resin from entering.

〔Effect of the invention〕

As described in detail above, the present invention involves introducing a main pig having a resin filling groove and a substitute material escape groove on the outer periphery into an existing pipe by pulling it with a towing rope, and introducing the main pig into an existing pipe. A movable pig is arranged on the front side in the direction of movement of the movable pig, and the resin is interposed between them so that the required filling pressure is generated in the resin by the movement of the two pigs, so that the following effects can be obtained.

(1) First, when applying pressure to infiltrate the inside of the sealing material of the pipe joint with resin in the pipe or filling and sealing between the joints, a special means is used to apply a predetermined filling pressure to the resin, such as applying pressure to fill the resin. A means for supplying compressed air, etc. can be made unnecessary, and the apparatus can be simplified.

(2) In addition, when transferring resin into the pipe via both pigs, if the groove on the outer circumference of the main pig matches the groove between the fittings at the position of the pipe joint, the resin will automatically move through the grooves. Since the sealing material is infiltrated under pressure or filled and sealed between the joints, there is no repair error (falling off) of the pipe joints, and a means for detecting the position of the pipe joints can be omitted.

(3) In addition, the main pig has an escape function for air, etc. that stays inside or between the sealing material during resin penetration and filling, so that the resin and air are effectively replaced and the resin penetrates and fills. The filling action can be performed accurately.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view partially cut away and showing one embodiment of the present invention, FIG. 2 is a perspective view showing the entire longitudinal section, FIGS. The figure is a perspective view of the pig. 1... Front pig, 2... Rear pig, 3, 4...
Groove, 5, 6... Towing rope, 12... Existing pipe,
13, 14...Pipe joint part, 13a...Large diameter part,
13b...tube end, 15...sealing material, 16...lead material, 18...sensor, 19...between, A...penetrating agent, B...putty agent.

Claims (1)

[Scope of Claims] 1. A main pig that is pulled by a towing rope inside the existing pipe and slides in airtight contact with the inner surface of the pipe, and on the front side in the moving direction, the main pig is in airtight contact with the inner surface of the pipe and slides against the towing rope. The main pig has a means for moving the resin under pressure by interposing a resin between the movable pig and the movable pig. The escape groove and the resin distribution groove that opens forward are shifted in position in the circumferential direction so that they do not communicate with each other, and are formed so that the opposing ends of both grooves overlap in the direction of movement. When the main pig passes through the pipe joint, the sealing material of the pipe joint and substitute substances such as air stagnant between the pipes are allowed to escape backward in the direction of movement through the escape groove, while the resin flows. A pipe joint repair device for an existing pipe, which is configured so that resin permeates and fills the sealing material of the pipe joint through the groove.