JP3161627B2 - Inner pipe lining method using ice pig - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing a pipe buried underground for city gas or water supply with resin, and more particularly to a pipe inner lining method for applying resin to the pipe inner surface using a pig. .

[0002]

2. Description of the Related Art Conventionally, there is known a pipe inner surface lining method in which an epoxy resin is applied to an inner surface of a pipe in order to repair an old underground pipe. One of the typical pipe inner surface lining methods is, as shown in FIG. 3, excavating working holes 20 at both ends of a repair target section of the pipe 1, cutting the pipe 1, and compressing one of the pipes 1 with a compressor 21. Unit 2
2. Connect the resin hopper 8 and connect the suction pump 23 and the receiver tank 24 that receives the extra resin 3 and the pig 25 that have been ejected to the other end. The resin 3 is moved by being pushed by the rubber pig 25, and is consumed while leaving the resin film 4 in the pipe 1. This operation is repeated to form the resin film 4 on the entire repair target section of the pipe 1. There is also a construction method in which the pig 25 is moved by pulling a wire.

As shown in FIG. 4, another pipe inner surface lining method is to directly feed resin by air pressure without using a pig, and to cut both ends of a repair target section of a pipe 1 to be repaired, and to connect one end to one end. Resin hopper 27, control device 3 for controlling pressure
0, an air cylinder 26 is connected, and a resin receiver 28 for receiving surplus resin ejected to the other end is connected.

[0004]

However, in the conventional pipe inner surface lining method using a pig, the rubber pig 25 is pulled by a wire or pressure-fed by air pressure.
The used pig 25 must be collected. Therefore, since both ends of the repair section of the pipeline must be opened, it is necessary to excavate the work hole 20 and cut the pipe 1 at both ends of the pipe 1 to be repaired, which causes an increase in work cost. Moreover, if an accident that clogs the pig 25 occurs, a lot of trouble such as excavation at the clogged portion and cutting of the pipe is required.

In order to avoid the inconvenience associated with the recovery of the pig 25, there is also a method of lining the inside of the pipe without a pig in which the resin is directly fed by air pressure without using the pig 25. Although it is not necessary, it is difficult to apply the soft resin 3 to a smooth surface with a uniform thickness only by controlling the pressurized air. Then, the surface becomes uneven due to the turbulence of the air pressure. Also,
When it is farther from the tip of the pipeline, that is, farther from the air pressure source, the resin film 4 tends to be too thick. As a result, the pipeline may be narrowed or the pipeline may be blocked due to improper construction.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a resin pipe and a pig having a diameter slightly smaller than the pipe diameter at one end of a pipe such as a gas pipe or a water pipe buried underground. And, by moving the pig by gas pressure to extrude the resin, in the pipe inner surface lining method of forming a resin film in the pipe, the pig is melted or sublimated at room temperature, and the ice pig is formed. Is characterized in that it is water that is frozen in a spherical or shell-like shape, or is an clathrate hydrate having a higher melting point than pure ice in order to suppress melting.

Further, according to the present invention, the substance to be mixed with water to form an clathrate hydrate is tetra-n-butylammonium bromide ((C ₄ H ₉ ) ₄ NBr) or tetrahydrofuran (C ₄ H ₈ O). ).

[0008] Further, the present invention relates to a gas pipe,
The resin is extruded by moving the pig by gas pressure, and when forming a resin film on the inner surface of the pipe, the pipe is cut only at one end of the repair section, and the pipe to be repaired by the sonic length measuring machine from the cut location. The step of measuring the length, then injecting the resin and the pig, and then moving the pig by gas pressure is repeated a plurality of times to perform lining of the required length on the inner surface of the tube.

[0009]

According to the present invention, since the pig is an ice pig that melts or sublimes at room temperature, the pig melts or sublimates and scatters after the pipe inner surface lining method is applied.
Even though the pig method is used, pig collection is not required at all. Therefore, it is not necessary to excavate work holes and cut pipes at both ends of the pipes to be repaired, but to excavate work holes and cut pipes only at one end of the repair section of the pipeline, and repair them with a sonic length measuring machine. The process of measuring the length of the pipe, then putting the resin and the pig therefrom and moving the pig may be repeated, and the inner lining of the pipe of a required length may be performed. Of course, if there is a riser pipe on the ground, cut the riser pipe on the ground, put resin in it, then put the pig and repeat the process of moving the pig, repeat the process of moving the pig to the required length. Since the surface lining only needs to be performed, there is no need to excavate the ground. Here, the term ice refers not only to water (H ₂ O) frozen, but also to a solid phase of a liquid or gaseous substance that is solid at low temperature and liquid at normal temperature.

When the ice pig is formed by freezing water into a spherical shape or a shell shape, it acts on the resin and smoothes the lining surface at the time of work as in the case of the conventional rubber pig, and melts after work. ,Evaporate. If the ice pig is a freezing clathrate hydrate with a higher melting point than pure ice, the melting of the ice pig will be slower. That is, it is difficult to unravel and can withstand a long working time. In addition, the melting point temperature increases, and handling becomes easier.

Substances having a high melting point in water are harmless and inexpensive so that they do not cause harm even if mixed with city gas or tap water, have no corrosiveness to gas pipes or water pipes and resins, and have stable properties. tetra-n-butylammonium having _{((C 4 H 9) 4} NBr) or tetrahydrofuran (C ₄ H ₈ O) are preferred. In the gas pipeline,
If the pressurized gas that extrudes the resin by moving the pig is the same type of pressurized gas as the gas in the gas pipeline,
No danger of explosion due to mixing of air and gas.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a pipe inner surface lining method using an ice pig according to the present invention. One end of a pipe 1 to be repaired is cut, and a resin hopper 8 and a gas cylinder 5 are cut there.
Connect. A surge tank 6 is connected between the resin hopper 8 and the gas cylinder 5 via a three-way valve 7. The surge tank 6 temporarily stores, at a constant pressure, the same gas as the gas in the gas pipe, such as city gas, stored under pressure in the gas cylinder 5, and supplies a pressurized gas for ice pig propulsion while maintaining a constant pressure.

A resin hopper 8 is connected to the pipe 1 on the resin supply side. A predetermined amount of the resin 3 and the ice pig 2 are put in the resin hopper 8. Resin 3 is the temperature of ice pig 2 (described later)
In consideration of the above, an epoxy resin having a viscosity that does not affect the lining performance even when cooled to 4 to 11 degrees is preferable. Specifically, an epoxy resin having a viscosity of 20,000 to 70,000 cps at a temperature of 5 degrees is preferred. It is suitable. Since there is no need to collect the pig 2 at the other end of the section to be repaired of the pipe 1, no treatment is required. In the embodiment of FIG. 1, if the section between the pipe 1 and the pipe connection portion 9 of the main pipe 13 is a repair target section, the required resin is obtained by the thickness of the resin film 4 × the circumference of the pipe 1. Normal,
Since the resin lining of about 1 to 4 meters can be performed by one pig run, the supply of the resin 3 and the ice pig 2 and the lining work may be appropriately repeated according to the length of the pipe to be repaired.

A speaker 11 and a microphone 12 are attached to the resin hopper 8 and connected to a sonic length measuring device 10. The acoustic wave length measuring device 10 includes a transmitter for repeatedly generating a pulse sound from the speaker 11, a time measuring circuit for measuring a time from when the reflected pulse sound received by the microphone 12 is transmitted, and a reflection time obtained by multiplying the time by a sound speed. And an arithmetic circuit for calculating a distance to the object that has been made.
Since the connection portion and the bend portion of the pipe and the like emit reflected waves having their own amounts and waveforms, the distance to the bend portion 1a and the pipe connection portion 9 of the pipe 1 can be measured in the example of FIG. Also,
During the lining work, the distance to the ice pig 2 can be measured.
The sonic length measuring device 10 has been developed by the present applicant. For details, refer to Magazine Pipeline Information No. 37 (November 1991).

The ice pig 2 can be sufficiently used for practical use even if water is frozen in a freezer in a spherical shape or a shell shape. However, in order to suppress melting, an inclusion hydrate having a melting point higher than that of pure ice, that is, water molecules is used. Comprises tetra-n-butylammonium bromide ((C
₄ H ₉ ) ₄ NBr) or tetrahydrofuran (C ₄ H ₈₎
It is difficult to melt when a mixture of substances having a crystal structure of the nature into which O) enters is frozen. Ice containing these substances is called clathrate hydrate, and is much less likely to melt than ordinary ice. In addition, tetra-n-butylammonium bromide and tetrahydrofuran do not react even when mixed into city gas or tap water, have no harm to the human body, are easily available and inexpensive, and are used for gas pipes or water pipes and resins. It has no corrosive properties and has stable properties.

FIG. 2 is a table showing measured values of the melting points at various concentrations of aqueous solutions of tetra-n-butylammonium bromide and tetrahydrofuran.

The ice pig remains in the main pipe 13 after use and gradually melts, and water and tetrahydrofuran are diffused as vapor in the gas, and tetra-n-butylammonium bromide becomes a viscous fluid and becomes main fluid. 13, gradually diffuses into the gas and disappears, and eventually burns together with the gas.
The ice pig 2 can be easily made by putting it in a mold having a diameter smaller than the inner diameter of the pipe 1 to be repaired by 2 to 3 mm and freezing it in a freezer or the like, and can be easily stored and transported in an insulated box containing dry ice.

[0018]

According to the present invention, the pig is melted or sublimated at room temperature, so that the pig is melted and scattered after the pipe lining is constructed. No collection is required. Therefore, the pipe may be cut at one end of the repair section of the pipe. If there is a riser pipe that has come out on the ground, it is only necessary to cut the riser pipe on the ground, so there is no need to excavate the ground. In addition, since an ice pig is used, it has the effect of pressing the resin and smoothing the lining surface in the same manner as the conventional rubber pig, and the lining surface is better than that obtained by the conventional method without a pig.

If the ice pig is formed by freezing a clathrate hydrate having a melting point higher than that of pure ice in order to suppress the melting of ice, the melting rate is reduced. That is, it is difficult to unravel and can withstand a long working time. Also, if the melting point temperature is high, handling becomes easy. In the gas line, the pressurized gas that moves the pig to extrude the resin is a pressurized gas of the same type as the gas in the gas line, and is made of tetra-n-butylammonium bromide ((C ₄ H ₉ ) ₄ NB
r) or tetrahydrofuran (C ₄ H ₈ O), there is no danger of explosion due to the mixture of air and gas,
It is harmless and inexpensive, and has no corrosiveness to pipelines. When forming a resin film on the inner surface of the pipe, the pipe is cut only at one end of the repair section, the length of the pipe to be repaired is measured from the cut portion by a sonic length measuring machine, and then the resin and the pig are removed. The step of moving the pig by gas pressure after injection is repeated a plurality of times, and the pipe inner surface lining of a required length is performed, so that the lining resin is securely used without waste and the working time can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a pipe inner surface lining method using an ice pig according to the present invention.

FIG. 2 is a table showing the melting points of aqueous solutions of tetra-n-butylammonium bromide and tetrahydrofuran.

FIG. 3 is a sectional view showing a conventional pipe inner surface lining method using a rubber pig.

FIG. 4 is a cross-sectional view showing a pipe inner surface lining method by a conventional method without a pig.

[Description of Signs] 1 Piping 2 Ice pig 3 Resin 5 Gas cylinder 8 Resin hopper 10 Sound wave length measuring machine

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaaki Itagaki 5-28-37 Sasashita, Konan-ku, Yokohama-shi, Kanagawa (72) Inventor Kiyoshi Shinkaku 1456, Hazama-cho, Hachioji-shi, Tokyo Three Bond Co., Ltd. (72) Invention Person Takaro Ebinuma No. 1 Kumoide Kokancho, Tsu City, Mie Prefecture Nippon Kokan Co., Ltd. Applied Technology Research Laboratories (56) References JP-A-3-288576 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ B05D 1/00-7/26 B05C 7/00-21/00 F16L 55/16

Claims (3)

(57) [Claims] A resin and a pig having a diameter slightly smaller than the pipe diameter are injected into one end of a pipe such as a gas pipe or a water pipe buried underground, and the resin is extruded by moving the pig by gas pressure. in inner surface lining method of the conduit forming the resin film into conduit, the ice pig melting or sublimating the pig at room temperature, ice
Pigs are made by freezing water into balls or shells
Clathrate with a higher melting point than pure ice to prevent melting
A pipe inner surface lining method characterized by being a hydrate . 2. Mixing with water to form clathrate hydrate
Is tetra-n-butylammonium bromide ((C ₄
H ₉ ) ₄ NBr) or tetrahydrofuran (C ₄ H ₈₎
The pipe inner surface lining method according to claim 1, wherein the method is O) . 3. A pig by gas pressure in a gas pipeline.
To extrude the resin to form a resin film on the inner surface of the pipeline.
The pipe at only one end of the repair section.
Of the pipeline to be repaired by the acoustic length measuring machine from the cut point
Measure the length, then inject the resin and pig, then pressurize
Repeat the process of moving the pig several times to
The pipe inner surface lining is performed.
2. The pipe inner surface lining method according to 2.