JPH0131077B2 - - 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 portion of an existing gas pipe is mainly buried underground. The present invention relates to a method for repairing a pipe joint of an existing pipe to be repaired.

[Conventional technology]

In recent years, various methods have been proposed for repairing existing pipes buried underground, such as gas pipes and water pipes, from the inside of the pipes while remaining buried so as to restore the pipes from corrosion and the like. In particular, in the case of existing gas pipes buried underground, in which cast iron pipes are connected by water-type joints, there is a need to repair the sealing properties of the pipe joints. For this reason, a construction method has been proposed in which the pipe joint part is first impregnated with a low-viscosity resin for penetration and then filled with a putty-like high-viscosity resin.

[Problem to be solved by the invention]

In other words, recently, city gas has become dry natural gas instead of the coal gas that had been used for a long time. However, in the case of dry natural gas, the sealing material dries and shrinks, causing deterioration of the sealing properties. This causes the sealing performance to deteriorate and cause gas leakage, so we ensure the sealing performance of the pipe joint and repair it using the above two steps to prevent sealing deterioration in the future. There were problems in that the two-step process took a long time and the work was complicated.

The present invention was proposed based on the above-mentioned circumstances, and in order to ensure the sealing of the pipe joint, a low-viscosity resin for penetration is impregnated into the sealing material interposed in the joint, and the air is removed. In addition, putty-like high-viscosity resin is filled between the pipe joint parts to seal the gap.In particular, the penetration of these resins and the putty-like high-viscosity resin filling are It is an object of the present invention to provide a method for repairing a pipe joint of an existing pipe, which can be reliably and quickly accomplished in one continuous operation in the process of passing a triple pig into the pipe of the existing pipe.

[Means to solve the problem]

For this purpose, the present invention provides that, within the pipe of the existing pipe,
Three pigs at the front and rear that slide in airtight contact with the inner surface of the pipe are installed inside the tube, and air escape grooves are provided on the outer periphery of the two front pigs among these three pigs, and the two pigs at the front A low-viscosity resin for penetration is filled between the two pigs on the rear side, and a high-viscosity resin in the form of putty is filled between the two pigs on the rear side, and the joint part of the existing pipe is located at a position corresponding to between the two pigs on the front side. At the same time, the low-viscosity resin is impregnated into the sealing material while allowing the air inside the joint to escape from the air escape groove of the pig, and the joint is connected at a position corresponding to between the two pigs on the rear side. It is characterized in that the space between the parts is filled with a putty-like high viscosity resin while allowing the air in the space to escape through the air escape grooves of the pig.

[Effect]

With the above configuration, the two front pigs infiltrate the pipe joint with low viscosity resin, and then the two rear pigs fill it with high viscosity resin, completing two tasks in one stroke. .

〔Example〕

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

In the figure, reference numerals 1, 2, and 3 indicate first to third pigs to be inserted into an existing pipe A buried underground, with the first pig 1 being the first to be introduced.
between the first pig 1 and the second pig 2, and the second pig
Connecting ropes 4 and 5 are connected between the pig 2 and the third pig 3, respectively, and a towing rope 6 that also serves as a length measurement is connected to the tip of the first pig 1. The first pig 1 and the second pig
As seen in the figure, the rear end has a cylindrical appearance with an oblique cutting surface cut from the top and bottom.
Air escape grooves 7 and 8 extending in the front-rear direction beyond the vertical section including the cut surface are formed on the circumferential surfaces on both sides of the pigs 1 and 2.
and 2 are open in front of each other. The above pigs 1 to 3 all have elasticity, and have a structure that allows them to be pulled forward by traction (or by combined use with air suction negative pressure) while coming into close contact with the inner peripheral surface of the existing pipe A. ing.

In the present invention, the space between the first pig 1 and the second pig 2 is filled with a low-viscosity resin for penetration, such as a low-viscosity epoxy resin, and the space between the second pig 2 and the third pig 3 is filled with a low-viscosity resin for penetration, such as a low-viscosity epoxy resin. is filled with a putty-like high-viscosity resin, such as a high-viscosity epoxy resin. Then, insert the three pigs 1, 2, and 3 filled with resin into the existing pipe A, and apply a predetermined negative pressure (for example, -0.5 Kg/cm ² ) inside the front pipe of the first pig 1. , it is moved within the existing pipe A by being pulled by the rope 6. During this process, even if air is trapped in the sealing material C of the pipe joint B, this air is sucked out from the sealing material C by negative pressure.

Then, as the pigs 1, 2, and 3 move, the first pig 1 at the head moves to the position shown in FIG. Pressurized air (for example, 0.5 Kg/cm ² ) is applied from behind the pig 3 to press the pig 3. As a result, the pig 2 is further pressed through the filler, and pressure is applied to the filler between the first pig 1 and the second pig 2, so that the low viscosity resin is inside the sealing material C at the joint. be penetrated. At this time, the air remaining in the sealing material C is replaced and moves from the gap D in the pipe circumferential direction, and escapes to the space in front of the pig 1 via the grooves 7 and 8, so that the resin is transferred to the sealing material. It does not prevent it from being impregnated into C.

Next, by pulling the towing rope 6, when the pigs 1, 2, and 3 move as shown in FIG.
The rear ends of the grooves 7 and 8 are in contact with the inner peripheral surface of the existing pipe A, and the space between the first pig 1 and the second pig 2 is airtight, and the internal space is expanded by the tension of the connecting rope 4. The filling pressure to the resin is lost. and the fourth
As shown in the figure, when the second pig 2 comes to a predetermined position with respect to the pipe joint part B, pressurized air is again applied from the rear of the third pig 3, causing the space between the second pig and the third pig to contract. The high viscosity resin is filled into the space D under pressure. In this case, since the rear ends of the grooves 7 and 8 of the second pig 2 face the gap D, the low viscosity resin remaining in the gap D from here will be absorbed by the grooves 7 and 8 of the second pig 2. Escape between the 1st Pig 1 and the 1st Pig.
This does not prevent the resin in D from being replaced and filling the space D with a high viscosity putty-like resin.

In this way, the first
In the first step, the sealing material is impregnated with the low-viscosity resin, and then in the second step, the high-viscosity resin is filled as putty into the space D inside the pipe joint part B. By impregnating the sealing material C with the low viscosity resin under pressure, even if the sealing material C in the pipe joint part B dries and shrinks to form a void, the void is filled by the impregnation with the penetrating agent A and is sealed.

In addition, in the second step, high viscosity resin is pressurized and filled into the butt gap D in the pipe joint B, so that the high viscosity resin replaces the low viscosity resin in the space D between the pipe joint B. Since it is replaced and filled, the interval is
D can be completely sealed.

In addition, even if there is a branch pipe E as shown in Figure 5 during the movement of the triple pig, since no pressurizing force is applied to the filler during the towing movement, the resin will not flow into the branch pipe E. There is no inflow of water, and there is no risk of blockage.

In addition, in the above embodiment, the first and second pigs 1 and 2 have a special shape with grooves 7 and 8, but in short, when pressure is applied to fill the pipe joint with resin, the joint Of course, other shapes may be used as long as the structure allows air or resin to escape in the circumferential direction from D between the parts.
Furthermore, pressurized air from behind the pig 3 is not necessarily required.

〔Effect of the invention〕

As described in detail above, in one continuous operation, the present invention first impregnates a low-viscosity resin into the sealing material of a pipe joint, and then injects a putty-like high-viscosity resin into the recess of the pipe joint. As a result, the pipe joints of existing pipes have a sealing effect by impregnating the sealing material with low-viscosity resin, and a sealing effect by filling the abutment gap of the pipe joint with high-viscosity resin. Since a double sealing effect is obtained, the pipe joint of the existing pipe can be reliably repaired to prevent seal deterioration in the future.Moreover, this can be done by simply inserting the pig into the existing pipe once. Since it can be carried out continuously by moving, it is possible to repair pipe joints with high work efficiency and high efficiency.

In addition, in the case where impregnation with a low viscosity resin and filling with a putty-like high viscosity resin are performed simultaneously in one continuous operation as in the present invention, the low viscosity resin impregnated in the first step is Since it also serves as a lubricant for the filling with the high-viscosity resin in the second stage, the putty-like resin has good filling properties even if it is highly viscous, and the surface between the pipe joints is uneven. Even on rough surfaces, the putty-like resin filling has good adhesion and can enhance the repair effect.

[Brief explanation of drawings]

FIG. 1 is a longitudinal side view showing an embodiment of the present invention, FIG. 2 is a perspective view showing an example of a pig shape, and FIGS. 3 to 5 are progress of work in an embodiment of the method of the present invention. FIG. 2 is a vertical cross-sectional side view showing the embodiment of FIG. 1; 1~3...Pig, 4,5...Connecting rope, 6...
...Towing rope, 7, 8...Groove, A...Existing pipe, B...Pipe joint, C...Sealing material, D...Between, E...Branch pipe.

Claims (1)

[Claims] 1 Inside the existing pipe, three pigs at the front and rear that slide in airtight contact with the inner surface of the pipe are installed, and grooves for air escape are provided on the outer periphery of the two front pigs among these three pigs. The space between the two front pigs is filled with a low-viscosity resin for penetration, and the space between the two rear pigs is filled with a high-viscosity resin in the form of putty. The low viscosity resin is impregnated into the sealing material while allowing the air inside the joint to escape from the air escape grooves of the pigs at positions corresponding to between the two pigs on the rear side. A pipe joint for existing pipes characterized in that a putty-like high-viscosity resin is filled between the joint parts at positions corresponding to each other, while allowing the air within the space to escape through the air escape grooves of the pig. Part repair method.