JPS6156033B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is useful for repairing leaks in indoor piping or underground pipes for passing gas, water, cable lines, etc., or for preventing leakage in cases where there is a risk of leakage. This invention relates to a coating method that prepares for future leakage by forming a film with a sealant on the inner surface of a pipe.

In conventional construction methods of this type, for example, the leakage location was detected and the leakage location was locally coated with sealant from the outside, the blockage repaired, or the local pipe replaced, but in this case, Not only is it difficult to search for the leakage point and requires a great deal of time and expense, but if the leakage point is not exposed to the outside, the leakage point must be exposed and restored to its original state after repairs. For example, in the case of pipes buried in concrete, the concrete must be destroyed and concrete poured after repairs, and in the case of pipes buried underground, the soil must be excavated and then backfilled and roads restored after repairs. This required extensive construction work, leading to further deterioration in latheability.

Therefore, a method has been developed in which a liquid sealant is injected into the leaking pipe to cover the leakage point from inside the pipe, but since the sealant is in liquid form, the injection and discharge itself is relatively difficult. In addition, it takes a long time to dry and solidify due to the small contact area with the air inside the piping.
The runner-up is that due to its own weight, air accumulates at the lower end of the pipe cross section, or air pockets form locally, making it difficult to form a homogeneous film around the entire circumference, or when the pipe bends in the vertical direction. If the sealant is bent or branched, it is more difficult to pump the liquid sealant from the lower part of the bend to the upper part, which makes it impossible to reliably cover the leakage area, and it is even more difficult to drain excess sealant. Additionally, there are drawbacks such as requiring a large amount of sealant and inhibiting internal fluid flow.

In both of the above cases, since the piping is partially coated, there is the inconvenience that if a leak occurs later in another part of the same piping, the same treatment will have to be applied again. Ta. In other words, in a pipe that has leaked even once, corrosion and internal stress distortion due to external forces have progressed on average over its entire length and circumference.Therefore, even if only the leaking area is temporarily coated, There is a high possibility that the leakage will repeat in the future.

The present invention has been developed to address the leakage tendency and problems with conventional construction methods, and allows the amount of sealant used to be reduced, and the sealant to be injected easily and quickly. Even if the pipe is covered, it is possible to reliably inject the sealant, and once the pipe has been coated, it can be kept in a safe state without leakage for a long period of time over its entire length and circumference. The purpose is to propose a treatment method.

That is, the piping inner surface coating treatment method according to the present invention is as follows:
After injecting and filling the liquid sealant in the form of foam into the piping, air is supplied into the piping to discharge the excess sealant from the piping, thereby discharging the residual sealant entirely onto the inner wall surface of the piping. The remaining sealant is dried and solidified.

In other words, instead of injecting the sealant into the piping as a liquid, it is injected in the form of a foam,
Easy injection, with low injection resistance from the inner wall of the pipe.
Can be injected quickly.

Furthermore, by injecting the sealant in the form of a foam instead of liquid as described above, and by discharging the excess sealant outside the pipe by supplying air into the pipe, and reusing this discharged sealant. , the amount of sealant to be used can be reduced.

Furthermore, since the sealant is in the form of a foam, excess sealant can be discharged easily and quickly, and therefore, the sealant can be injected and discharged even if the pipe is bent in the vertical direction. In addition, the sealant does not accumulate on the lower end of the cross section of the inner wall of the pipe due to its own weight, and since the bubbles contain air, they dry and solidify quickly. It can be firmly attached to the entire surface and quickly solidified and dried.

The synergy of the above effects has made it possible to coat the inner surface of piping efficiently and economically.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a small diameter gas pipe installed indoors, part of which is buried within a concrete wall. Here, 1 is a gas pipe, 2 is a tip, 3 is a valve, and M is a flow meter.
is refracted relatively significantly in the vertical direction depending on the surrounding conditions.

When a gas leak occurs somewhere in the gas pipe 1, close the valve 3, open the tank 2, purge the gas, remove the meter M, and install the bubble generator 4 shown in FIG. Connecting. This bubble generator 4 consists of a storage tank 4A for liquid sealant s and a blower 4B for supplying air under pressure, and an air supply pipe 5 taken out from the blower 4B is branched into two parts, one of which is connected to the gas pipe 1. The other is connected to the bottom of the storage tank 4A through a valve 6C through valves 6a and 6b. 7 is a pipe connected to the pot 2, and 8 is a discharge sealant receiving container.

The procedure for repairing a leak in the gas pipe 1 is as follows.

When the valve 6a is closed and the valves 6b and 6c are opened to operate the blower 4B, air is blown into the bottom of the storage tank 4A, preferably through a large number of small holes, and the storage tank 4A is made of latex with a viscosity of 10 to 100 centipoise. The liquid sealant inside bubbles as air is blown into the inside, and the foamy sealant s produced in the storage tank 4A is injected into the gas pipe 1 from the air supply pipe 5.

When the foam sealant S reaches the container 8, the blower 4B is stopped. In this state, the gas pipe 1 is filled with the foam sealant S over its entire length. In this state, the valve 6C is closed, the valve 6a is opened, and the blower 4B is operated again. Then, the foam sealant S filled in the gas pipe 1
As shown in FIG. 3A, the air is continuously pumped by compressed air to form a diaphragm that is intermittent in the axial direction of the gas pipe 1 and is in contact with the entire inner wall surface of the gas pipe 1. It ends up being discharged to the container 8 side.

When the amount of excess sealant flowing into the container 8 reaches a predetermined amount, the blower 4B is stopped. In this state, a ring-shaped sealant S' of a uniform thickness remains attached over the entire circumference of the inner wall surface of the gas pipe 1 and over its entire length in the axial direction. This residual sealant S' is in the form of foam, and is dried and solidified for a predetermined period of time. In this case, the residual sealant S' gradually liquefies from the inner surface side to the outer side, and finally becomes a thin film-like ring shape with no or few internal bubbles (Figure 3 B), and gas The tube 1 is now completely coated over its entire length and circumference.
If necessary, the sealant S' can be forcibly dried in a foamy state, that is, in a state in which it contains many closed cells, by blowing drying hot air into the gas pipe 1. It is also possible to solidify.

FIG. 4 shows another embodiment, which relates to leak repair in a large-diameter gas main pipe 1 buried underground. In this case, since the gas main pipe 1 has a large diameter, the pipe 9 having an outer diameter slightly smaller than the inner diameter of the gas main pipe 1 is arranged concentrically or almost concentrically within the gas main pipe 1. After injecting the foam sealant S into the ring-shaped space 10 of both tubes 1 and 9 using the same bubble generator 4 as described above, air is introduced to remove the excess sealant. While removing and cleaning the pipe 9, the ring-shaped residual sealant S in the gas main pipe 1 is removed.
Dry and solidify. In this case, the pipe 9 may be flexible, simplifying the construction work, and
The amount of sealant S used can be reduced, and drying and solidification can be speeded up, resulting in efficiency and economy. Further, after the sealant S is made into a foam and is injected and filled into the gas main pipe 1, a pipe 9 having an outer diameter slightly smaller than the inner diameter of the main pipe 1 is inserted concentrically or almost concentrically. It is also possible to implement it by

The construction method of the present invention can be applied not only to gas main pipes, but also to branch pipes, water pipes, and cable line pipes derived from these pipes, and is not limited to repairing leaky pipes, but also to new or corroded pipes. This may be carried out for the purpose of preventing leakage in pipes where leakage is progressing.

Further, as the sealant S, the following can be used.

That is, latexes such as butyl rubber, polysulfide rubber, and natural rubber, vinyl acetate. Ethylene copolymer latex, styrene-butadiene polymer latex,
Acrylonitrile butadiene polymer latex, methyl methacrylate butadiene copolymer latex, vinylpyridine copolymer latex, chloroprene latex, vinyl chloride polymer, vinyl acetate polymer, vinylidene chloride copolymer, Examples include latexes such as 1,4 polyisoprene, polyurethane, polybutene, polyacrylate, and polyethylene.

[Brief explanation of the drawing]

The drawings show an embodiment of the piping inner surface coating method according to the present invention, and Fig. 1 is a schematic side view showing a gas pipe installed indoors, and Fig. 2 is a schematic side view showing a means for repairing leakage of the gas pipe shown in Fig. 1. 3A and 3B are sectional views showing the state of the sealant, and FIG. 4 is a schematic vertical sectional side view showing leakage repair means for underground gas pipes. 1...Piping, 9...Pipe, S...Sealant, S'...
...Residual sealant.

Claims (1)

[Claims] 1 After injecting and filling the liquid sealant s in the form of a foam into the pipe 1, air is supplied into the pipe 1 to discharge the excess sealant in the pipe 1, thereby removing the residual sealant s'. A method for coating the inner surface of a pipe, which is characterized in that the sealant s' is completely adhered to the inner wall surface of the pipe 1 and the remaining sealant s' is dried and solidified.