JPH0156315B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is mainly concerned with repairing the pipe joints of existing gas pipes buried underground so as to ensure sealing performance from the inner surface of the pipe while the pipes are still buried. 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 from the inside so as to regenerate the pipes from corrosion and the like while the pipes 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, and in the case of conventional coal gas, the tar component in the gas is removed by 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 contracts, creating voids and causing the seal to deteriorate. The sealing properties of the pipe joints should be ensured to prevent
Since then, it has become necessary to carry out repairs to prevent seal deterioration.

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 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.

Therefore, the present application has a means for filling and moving a resin between at least a pair of front and rear pigs that slide into and in airtight contact with the inner surface of the pipe in an existing pipe, and in this movement process, the pipe joint portion moves back and forth. We previously proposed a method in which suction is applied from part of the outer circumference of one of the pigs when the pig is located between the two. Here, first, a low-viscosity resin penetrant is impregnated into the sealing material under pressure through the gap in the joint, and then a high-viscosity resin putty is filled into the gap in the joint. In this case, when pressurizing the penetrant, air is removed from the gap in the joint by suction force, and the penetrant is replaced and impregnated into the sealing material through the gap. Also, when filling a putty-like filler (hereinafter referred to as putty agent) under pressure, excess penetrant is removed from the gap at the joint part using the filling pressure, and the putty agent is filled into the gap to replace it. Ru.

As a result, not only can a worker be outside repairing the inner surface of a pipe joint while it is buried, but the penetrating agent impregnated into the sealing material under pressure can eliminate micropores caused by drying and shrinkage of the sealing material. This improves the sealing effect, and the penetration of the penetrant into the gap in the first stage acts as a lubrication for the filling of the putty in the second stage. Even if the surface of the gap was uneven and rough, the filling adhesion of the putty agent was good, and the double airtightness of the penetrant and the putty agent made it possible to achieve a repair with a high sealing effect.

[Problem to be solved by the invention]

Several devices have been proposed previously for this method of repairing the inner surface of pipes, but existing pipes have curved parts such as elbows, so they must be adaptable to these curves. be. In addition, there may be slight differences in the inner diameters of the pipes that are connected to each other through the pipe joints, so pressurized air is supplied to the rear pig to fill the pipes with penetrants and putty agents. Even if you try to push it in, it may not slide smoothly, making it impossible to reduce the space between the pigs and applying filling pressure to the resin. Since the situation cannot be detected from the outside, it is difficult to be sure of repair.

The present invention has been made based on the above circumstances, and it is possible to reliably secure the filling pressure for the resin at the pipe joint part, and also to obtain flexibility at curved parts such as elbows, so that smooth movement can be achieved. The present invention aims to provide a pipe joint repair device for existing pipes.

[Means to solve the problem]

For this purpose, the present invention provides that, within the pipe of the existing pipe,
At least a pair of front and rear pigs that slide in airtight contact with the inner surface of the tube are provided, and a means for filling and moving resin between the pigs is provided, and a suction groove and a resin filling groove are provided on the outer periphery of the front pig. A rear pig is connected to the front pig via a connecting rope, and a capacity expansion mechanism is provided between the pigs. A flexible bag is provided, and the flexible bag passes through the rear pig and communicates with a pressurized air source, and when the pipe joint portion is located between the front and rear pigs during the movement of the two pigs, the pressurized air is supplied to the flexible bag. The invention is characterized in that the flexible bag is inflated by air pressure applied from a source to apply filling pressure to the resin.

[Effect]

With the above configuration, the resin can be smoothly filled into the pipe joint part, and the pig can be easily moved even in curved parts of the pipe.

〔Example〕

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

1 to 3, reference numeral 1 denotes a cylindrical front pig, which is connected to a similarly cylindrical rear pig 3 via a connecting rope 2. Both the pigs 1 and 3 have small-diameter connecting portions 1 at opposing portions.
A, 3a are formed, and a cylindrical flexible bag 4 is arranged between them, and both ends of the bag are tightened with bands 5, 5' to form a sealed inflatable space 6.

The flexible bag 4 is an airtight bag made of rubber or resin, and can maintain airtightness itself. Further, the rear pig 3 is formed with an air supply hole 7 that penetrates into the bag 4 from the rear.
Pressurized air can be applied from the rear of the rear pig 3. The rear pig 3 has an airtight fin 3b on the outer periphery of its rear end to maintain airtightness. Further, tow ropes 8 and 9, which also serve as length measurement, are connected to both the pigs 1 and 3, respectively.
On the outer periphery of the pig 1, a suction groove 10 that opens on the tip side and a filling groove 11 that opens on the rear side overlap each other in the axial direction,
They are formed at different positions in the circumferential direction.

The repair device having such a configuration is used in the following manner for repairing the inner surface of the existing pipe 12. here,
The existing pipe 12 buried underground is a cast iron pipe using a conventional piping method, and is connected to pipe fittings 13 and 14 of a water type etc.
It is something that has been connected for a long time via . When repairing the pipe joints 13 and 14 of the existing pipe 12,
In the present invention, the existing pipe 12 is divided into units of length suitable for repair, and a plurality of pipe joints 13 and 14 interposed within that section are repaired. For example, the large diameter portion 13a provided at the end of one pipe is connected to the end 1 of the other pipe.
3b are butted against each other, and a sealing material 15, which is usually referred to as "hemp skin", is stuffed into the butt-fitting part.
It has a connection structure in which the opening is sealed with a lead material 16. Further, the pipe joint part 14 is fitted with a large-diameter pipe joint member 17 so as to cover the ends of the existing pipes facing each other, and the above-mentioned sealing material is applied to the fitting part with the existing pipes. It has a connection structure in which the opening is sealed with a lead material.

The pigs 1 and 3 are introduced into the existing pipe 12 to be repaired from one opening. In the present invention, in the space facing both pigs 1 and 3 (excluding the space occupied by the bag 4), for example, a penetrating agent A of a low viscosity resin (10 cps to 1000 cps) having hardenability such as an epoxy resin, Alternatively, it is filled with a putty agent B of high viscosity resin (for example, 10,000 to 300,000 cps), and is moved within the existing pipe 12 by being pulled by the pulling rope 8 .

In the first stage, as shown in Fig. 2, penetrant A is filled between pigs 1 and 3, and arrow
be moved in the direction. This movement causes a predetermined negative pressure (for example, -0.5
Kg/cm ² ), the pigs 1 and 3 are moved together with the penetrant A by the tow rope 8. During this moving process, the piping diagram and pulling out (length measurement) of the towing rope 8 are carried out.
Alternatively, the position of the pipe joint 13 or 14 can be confirmed by installing a video camera or a magnetic sensor 18 on the tow rope 8, and based on that determination, the pig 1 can locate the pipe joint 13 (or 14). When the pigs 1 and 3 move to this position, the movement of the pigs 1 and 3 is temporarily stopped or at a low speed, and in this state, the predetermined pressure (for example, +0.5Kg/
cm ² ) of pressurized air pressurizes the pig 3 in the direction of the arrow Y, and at the same time pressurized air is filled into the bag 4 through the air supply hole 7, and the expansion of the bag 4 increases the pressure in the direction of the arrow Z. and apply filling pressure to osmotic agent A.
As a result, the penetrating agent A is forced into the pipe joint part 13 through the groove 11 and permeates into the sealing material 15 through the gap 19 of the pipe joint part 13.

At this time, if there is an air leak in the pipe joint 13 or 14, the penetrant A will penetrate by pushing out the residual air in the sealing material 15, and if there is no air leak, the penetrant A will penetrate. The residual air in the sealing material 15 is trapped due to the pressurized penetration of the agent A, but in this case, the leading pig 1 has a groove 10, and the sealing material 1
The residual air in 5 circulates in the pipe circumferential direction from the gap 19 due to the push-out action caused by the pressurized infiltration of the penetrant A, and flows through the groove 1.
Because it escapes to the space in front of pig 1 through 0,
The effect of replacing air with the penetrant A is reliably performed, and the penetrant A is deeply penetrated into the entire area of the sealing material 15.

When the impregnating action of the penetrating agent A on one pipe joint 13 or 14 is completed, the pigs 1 and 3 are moved within the existing pipe 12 again by the negative pressure in front of the pig 1 and the pulling of the rope 8.

Through this process, the sealing material 15 is filled with penetrant A for each pipe joint. During this time, the amount of residual penetrant A decreases, but due to the expansion of bag 4, the sealing material 15 is filled with penetrant A. In particular, filling pressure can be applied to the resin until the final stage.

In this way, when the impregnation action of the penetrant A in the first stage is completed, in the second stage, as shown in FIG. Then connect this to the existing pipe 1 as described above.
2, and when the pigs 1 and 3 move to the relative position shown in FIG. Filling pressure is applied to the putty agent B through the pig 3 and bag 4 using compressed air. In this case, a surplus of the previous penetrant A remains in the gap 19, but suction force is applied from the front of the pig 1 via the groove 10, and filling pressure is applied to the putty agent B. Therefore, the putty agent B is filled through the grooves 11, and replacement can be realized.

Moreover, the penetrating agent impregnated under pressure in the first stage is
Since it acts as a lubricant for the filling of the putty agent in the second stage, even if the putty agent is a high-viscosity resin, resin filling can be achieved reliably. Even on a rough surface, the putty agent has good adhesion, and the effect of increasing both the airtight effect and the gap sealing effect of the putty agent can be obtained.

In addition, when penetrating the sealing material 15 with the penetrant A and filling the gap 19 with the putty agent B,
The pigs 1, 3 must pass through the elbow portion, as can be seen in FIG. 4, for example. At this time, the connecting rope 2 connecting the two pigs 1 and 3 is activated, allowing the device to bend and adapt to curved portions. This adaptability can be improved by reducing the length of each pig 1, 3 in the direction of movement. Therefore, it is best to select an appropriate length in consideration of airtightness with the inner wall of the pipe.

In the embodiment shown in FIG. 5, the air supply hole 7 of the pig 3 is connected to a pressurized air supply pipe 20 to effect the inflation of the bag 4. For this,
It is not necessary to supply pressurized air to the pig 3 from behind. Note that the pressurized air supply pipe 20 is opened to the outside, and the air inside the bag 4 can be discharged to reduce the size of the bag 4.

In the above embodiment, pressurization and suction are performed using air pressure, but it goes without saying that the magnitude of the air pressure can be adjusted depending on the situation. Moreover, the suction action may be omitted. Further, in the above embodiment, the movement of the pigs 1 and 3 was stopped or moved at a low speed at the pipe joint part 13 or 14, but as long as the above-mentioned infiltration and filling are performed reliably, The above-mentioned infiltration and filling actions may be performed while continuously moving at high speed within the existing pipe.

〔Effect of the invention〕

As described in detail above, the present invention connects a pair of front and rear pigs with a connecting rope, the front pig has a replacement function, and a bag is provided between the front and rear pigs, and the resin is inflated by expanding the bag. Because the filling pressure sent to the pipe joint is obtained through the front pig, for example, the pipe diameters are slightly different before and after the pipe joint, and the resistance is so strong that the rear pig cannot be moved forward by air pressure. Even if the resin filling space between the pigs is expanded, the required filling pressure can be reliably received by the expansion of the bag, and repair work to the pipe joint can be performed with certainty. In addition, the bag is flexible and can be adapted to pass through curved elbows, etc.
Facilitates passage of pigs.

[Brief explanation of drawings]

Fig. 1 is a partially longitudinal side view showing an embodiment of the present invention, Fig. 2 is a longitudinal sectional view showing the state of pressurized impregnation with the penetrant in the first stage, and Fig. 3 is a longitudinal sectional view showing the pressurized impregnation of the putty agent in the second stage. FIG. 4 is a longitudinal sectional view showing the state of filling, FIG. 4 is a longitudinal sectional view showing the state of passage through the elbow portion, and FIG. 5 is a side view of another embodiment. 1... Pig, 1a, 3a... Connection part, 2... Interlocking rope, 3... Pig, 3b... Fin, 4... Flexible tag, 5, 5'... Band, 6... Space, 7
... Space supply hole, 8, 9 ... Traction rope, 10,
11...Mizojo, 12...Existing pipe, 13, 14...
Pipe joint part, 13a...Large diameter part, 13b...Pipe end, 15...Sealing material, 16...Lead material, 17...
Pipe joint member, 18...Sensor, 19...Gap, 2
0... Pressurized air supply pipe, A... Penetrant, B... Putty agent.

Claims (1)

[Scope of Claims] 1. At least a pair of front and rear pigs that slide and move in airtight contact with the inner surface of the pipe are provided in the pipe of the existing pipe, and a means is provided for filling and moving a resin between the two pigs, and the front side A suction groove and a resin filling groove are provided on the outer circumference of the pig, overlapping each other in the axial direction, and at different positions in the circumferential direction. A flexible bag capable of expanding the volume is provided between the two pigs, and the flexible bag passes through the rear pig and communicates with a pressurized air source, and during the movement of the two pigs, the pipe is connected. A pipe joint for an existing pipe, characterized in that when the joint part is located between the front and rear pigs, the flexible bag is expanded by air pressure applied from the pressurized air source to apply filling pressure to the resin. Part repair equipment.