JPH03288576A - Method for treating inner surface of pipe - Google Patents

Abstract

PURPOSE:To carry out work without requiring the digging-up of piping and excavation and stopping gas by forming a pig from a composition whose shape is deformed or not left by liquification or gasification after the completion of lining. CONSTITUTION:A pig 6 formed from a composition gasified to disappear or liquefied to deform after the completion of a lining process to beome a state not bringing about any trouble in the flow of gas is used. By this method, the lining seal due to a resin can be simply and uniformly applied to the inner surface of gas piping without cutting a gas pipe or digging up an embedded part.

Description

[Detailed description of the invention] <Prior art> Buried underground or inside a building. In recent years, anti-corrosion methods have been developed to line and seal the inner surfaces of gas and water pipes with synthetic wood, etc., for the purpose of safety and maintenance.

Many have been developed.

Especially since the buried gas pipes in IB City have been in existence for 10 years, it is necessary to take even greater precautions for safety.

However, the above-mentioned method of lining the inner surface of the gas pipe involves digging up and cutting the buried pipe when lining is carried out, which has the disadvantage that the lining must be carried out with the gas supply turned off. In other words, in order to line the inner surface of the gas pipe with resin, either (a) force the resin using a large amount of air, or (CI) yellow the resin before the pig.
Pump the pig with low-pressure air and line it with resin, or
There are two methods: (c) applying a film to the inner surface of the pipe, and (d) mechanically introducing a lining robot into the pipe, but both of these methods are As it required cutting and excavating pipes at more than 9 locations,
The disadvantage is that the gas supply has to be stopped during the construction period.

Furthermore, due to the recent high-density urbanization and labor shortages, digging up roads and grounds as mentioned above increases costs and causes traffic congestion.

It is extremely uneconomical, and the situation is such that repair work cannot actually be carried out.

<Problems to be Solved by the Present Invention> As a result of research on lead content in view of the various drawbacks of the conventional lining method, the present invention solves the following problems: The present invention provides a method for uniformly lining and sealing the inner surface of a gas pipe with a resin, which is simple and easy to do (cutting the gas pipe or excavating the buried part).

Measures to Solve the Problems Generally, the resin transfer pigs used for lining are spherical or bullet-shaped, and more than one pig is used, and their composition is natural or synthetic rubber.

Constructed of various synthetic resins, they are devised to uniformly line the inside of the pipe, and pressure feeding is usually done using compressed air.

The present invention pays particular attention to the reasons behind these pigs.

Used for these linings. If you use a pig with a composition that will gasify and disappear after the lining process, or liquefy and deform, and will not cause any hindrance to the gas flow, it will be possible to cut the buried pipe at the outlet or dig into the trench. I came up with an idea that doesn't require resetting.

In other words, the lining pig has a composition that maintains a spherical insulator shape during lining, and gasifies or liquefies and loses its shape after a certain period of time after falling into the discharge pipe after lining is completed. We have come up with an invention that can solve various problems by using the .

The present invention is a method for construction without stopping the gas supply.

For the pumping of the pig of the above invention, instead of conventional air, gases such as city gas, LPG,
Propane or butane gas is used, and the pressure is slightly higher than the gas pressure. Further, the gas component for pressure feeding is not limited to the above, as long as there is no problem even if it is mixed and dispersed in the gas.

Further, the lining resin may be any resin as long as it has good lining properties.

The composition of the pig of the present invention may be any composition as long as it has a certain shape at the initial stage and disappears through gasification or liquefaction over time after lining is completed.Specifically, dry ice, There are ice, camphor, etc., but silicone resin is preferable because of the workability of lining! A composition called bouncing putty, which has an initial shape and liquefies and flows down over time, is suitable.

4 Example Next, specific examples of the present invention will be described.

[Example] Three ice pigs were used which were previously formed into spherical shapes in a freezer.

The piping shown in Figure 1 was installed and a lining experiment was conducted.

Using FIO, 5% propane gas for pressure feeding, place a relatively low viscosity epoxy resin mixture in front of the ice pig, and first move one ice pig from the direction of section a to the direction of section C in Figure 1. When pressure-feed lining was performed, the lining was completed in about 5 minutes. There was a small amount of resin discharged from CS, and the ice pig was a little smaller and chipped, so I put the remaining 2 pigs in part 3 and pumped it in the same way, and drained it to part 0. The ice pig turned into water in the piping in about 30 minutes, and there was no problem with gas flow.

Example 2 After the lining was completed, the putty gradually lost its shape in the discharge pipe and flowed down onto the inner surface of the pipe, causing no hindrance to the gas flow in the branch pipe, and the lining work was successfully completed.

Example 3 As in Example 1, a dry ice spherical pig was used for lining the ice pig.

The inner surface of the tube was well and uniformly lined. or.

After lining, the discharged pig was gasified into a layer for about 20 minutes and disappeared.

Comparative Example J I tried lining it using a double-barreled urethane sponge comb pig, which has been conventionally used.

Since the pig remained on the inner surface of the branch pipe and caused an obstruction to gas flow, the branch pipes and supply pipe branch points of parts 0 and 07 in Figure 1 were excavated, the pipes were cut, and the pigs were removed. At this time, the gas supply was cut off and the earth was excavated and rebuilt, causing a huge amount of time and economic loss.

Comparative Example 2 An attempt was made to simply inject one part of a low-viscosity lining resin while the gas was flowing and line the pipe with the resin itself under a pressure of 05 to 2 kA of propane gas, but the resin did not uniformly line the pipe. It was a close call. Furthermore, with a small amount of propane gas below the above pressure, most of the lining material only partially flows to the bottom of the tube, making lining impossible.

Effects of the Invention From the above explanation, the resin lining method for the inner surface of a pipe according to the present invention does not require excavation or cutting of the pipe, and the work can be done without stopping the gas supply, so the resin lining can be easily done. Because it is possible, the construction method is simple, and the construction period is shortened.

The economic effects are huge.

Procedural amendment (method) 1. Indication of the case Patent Application No. 87425 of 1990 2. Name of the invention Method for lining the inner surface of pipes 3. Person making the amendment Relationship with the case Patent applicant Co., Ltd. Zaiken Sagamihara, Kanagawa Prefecture Ichihoshigaoka 3-chome July 31, 1990 (starting gate) 5. Subject of amendment (1. Name of invention 6. Contents of amendment (1. Name of invention is corrected to "Method for lining the inner surface of a pipe."

(2) The entire specification shall be corrected as shown in the attached sheet.

(3) Correct the drawing as shown in the attached sheet.

Description 1. Title of the invention: Method for lining the inner surface of a tube. Lining Treatment Method 3, Detailed Description of the Invention [Purpose of the Invention (Industrial Application Field) The present invention relates to a method for lining the inner surface of a pipe, such as a gas pipe or a water pipe, for lining and sealing the inside of the pipe.

(Prior Art) Many anti-corrosion methods have been developed in recent years for the purpose of protecting and preserving gas pipes and water pipes buried underground or inside buildings, in which the inner surfaces of the pipes are lined and sealed with synthetic resin or the like.

In particular, underground gas pipes in cities are now several thousand years old, so it is necessary to pay even greater attention to safety. Generally, resin conveying bigs used for lining treatment are spherical or bullet-shaped, and more than one piece is used, and their composition is made of natural or synthetic rubber or various synthetic resins, and they can uniformly line the inside of the pipe. It is devised as follows, and the pressure feeding is usually done by compressed air.

However, the above-mentioned method for lining the inner surface of gas piping involves digging up and cutting the buried pipe during lining construction, which has the disadvantage that the gas must be shut off before construction. In other words, in order to line the gas pipe by pouring resin into the inner surface of the gas pipe, either (a) force the resin using a large amount of air, or (b) place the resin in front of the VIG, force-feed the VIG with low-pressure air, and remove the resin. Lining or
There are two methods: (1) pasting a film on the inner surface of the pipe, and (d) mechanically introducing a lining robot into the pipe, but both of these methods require that the piping be placed at two or more locations, the inlet and outlet. Since cutting and excavation were required, the gas supply had to be stopped during the construction period, which was a drawback.

Furthermore, due to the increasing densification of cities and labor shortages in recent years, digging up roads and sites as described above increases costs and causes traffic congestion, making it extremely uneconomical.
In reality, the situation is such that repair work cannot be done.

FIG. 1 is a side view schematically showing a gas pipe that undergoes a general lining treatment on the inner surface of the pipe. It flows into the piping section (5). If a crack or the like occurs on the inner surface of the pipe (1), resin and VIG are inserted from the injection port (3) side. When lining is performed using conventionally used double-barreled urethane sponge rubber pigs, the pipes remain inside the branch pipes and impede gas flow.
5), it was necessary to dig up the pipe, cut the pipe, and take out the VIG. At this time, the gas supply was stopped and the soil had to be excavated and backfilled, resulting in significant time and economic losses.

In addition, you can simply insert the inlet part (3) while the gas is still flowing.
When trying to inject a lining resin with a lower viscosity and line the pipe with the resin itself using propane gas at a pressure of 0.5 to 2 kg/ci, the resin did not spread over the inner circumferential surface of the pipe, making it difficult to line the pipe uniformly. . Furthermore, with a small amount of propane gas below the above pressure, most of the lining material only partially flows to the bottom of the tube, making lining processing difficult.

<Problems to be Solved by the Present Invention> In view of the various drawbacks of the conventional lining method, an object of the present invention is to provide a method for lining the inner surface of a tube in which the inner surface of the tube is uniformly lined and sealed with resin.

[Structure of the Invention] <Means/effects for solving the problems> The present invention pays particular attention to the composition of conventional pigs, and makes it possible for the pigs used for lining the inner surface of pipes to gasify and disappear after the lining process is completed. Alternatively, if a pig with a composition that liquefies and deforms and does not interfere with the flow of gas is used, there is no need to cut or dig up the buried pipe at the outlet. In other words, a lining pig is used that has a composition that maintains a spherical or fixed shape during lining, and that gasifies or liquefies and loses its shape after a certain period of time after falling into the discharge pipe after lining is completed. This led to an invention that solves various problems.

(Example) Next, specific examples of the present invention will be described.

(Example 1) A case will be described in which a pipe (1) is installed as shown in FIG. 1, and lining treatment is performed using three ice pigs (6) that have been previously formed into spherical shapes in a freezer. Second
The figure is a partial sectional view of the vicinity of the injection port (3) when a regulator (7) for gas adjustment is provided in FIG. 1. Ice pigs (6
), place a mixture of relatively low viscosity epoxy resin (8) in front of the valve (2), place one ice pig (6) in front of the valve (2).
) The pressure-feed lining process was performed from the direction of the injection port part (3) toward the middle part (4). Figure 3 shows a cross-sectional view of the vicinity of the middle part (4) of the pipe (1), in which the gas pressure (0.03 kg/cffl) from the direction of the arrow on the left side of the drawing is maintained, and the gas from the right side of the drawing is maintained. Ice pig by pumping (
6) was moved, and the amount of resin used as the pipe inner ring material discharged was small, and the ice pig (6) had become a little smaller and was missing, so the remaining two pigs (6) were reinstalled at the injection port. (3)
The mixture was sequentially injected from the direction, and similarly pumped and discharged to the discharge port (5). As a result, the resin (8
) was applied well, and the ice pig (6) was discharged to the outlet (5) while maintaining its shape, and in about 30 minutes it melted into water in the pipe of the outlet (5), and gas was released. There were no problems with distribution.

(Example 2) The same piping (1) as in Example 1 was lined with bouncing putty, which is a type of silicone resin, as a lining pig (1o). (5) The pig (12), which gradually lost its shape and liquefied inside, flowed down onto the inner surface of the pipe, causing no hindrance to the gas flow in the pipe, and the lining work was successfully completed.

(Example 3) When lining was performed using Triice's spherical pig (11) in the same manner as in Example 1, the inner surface of the tube was well and uniformly lined.

Since the discharged pig after lining takes several tens of minutes, the pig of the above invention can be pumped using gases that do not cause any problems even if mixed into the gas, such as city gas, LPG, etc., instead of the conventional air. Propane or butane gas is used, and the pressure is slightly higher than the gas pressure. Further, the gas component for pressure feeding is not limited to the above, as long as there is no problem in mixing and dispersing it in the gas. Further, the lining resin may be any resin as long as it has good lining properties.

The composition of the pig of the present invention may be any composition as long as it has a certain shape at the initial stage and disappears through gasification or liquefaction over time after lining is completed.Specifically, dry ice, ice , camphor, etc., but from the standpoint of lining workability, a so-called composition that is a type of silicone resin that has an initial shape and liquefies and flows down over time is suitable.

[Effects of invention FIG. 3 is a cross-sectional view showing the pig in a melted state.

1...Piping, 3...Inlet part, 4...
・Intermediate part 5...Discharge port part, 6.10, 11.
...Gas lining can be done easily because it does not require a pig or gas and can be worked without turning off the gas.

[Brief explanation of the drawing]

Claims (1)

[Claims] In the method of lining the inner surface of a pipe with resin using a pig, the pig is characterized by a composition that does not change its shape after lining, or does not leave its shape through liquefaction or gasification. , tube inner surface resin lining method