JPH09308859A - Method for coating inner wall face of pipe, and the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform rust prevention after iron rust is removed before coating of the inner wall face of a pipe is performed. SOLUTION: After iron rust is removed by sand-blast cleaning, the terminal end pipe opening is sealed and, from the apex end pipe opening, a tannic acid soln. compounded with a water-soluble polymer made of vinyl chloride, acrylic and polyvinylidene chloride, and saran is filled up therein for coating. After the above described tannic acid soln. penetrates enough all the corners, this soln. is removed and by drying it enough until water is removed to perform rust prevention. After this process is finished, coating is performed by lining processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coating an inner wall surface of a pipeline, such as a water pipe, through which a liquid and a gas flow.

[0002]

2. Description of the Related Art As a conventional method for coating the inner wall surface of a pipe or the like, after performing sandblast cleaning, a coating lining work is performed to coat the inner wall surface of the pipe or the like.

[0003]

In the conventional method of coating the inner wall surface of a pipe or the like, as described above, since the coating lining is carried out after the sandblast cleaning, the rough rust cannot be removed. However, iron rust remains in the pinhole part and it is not possible to prevent this iron rust, so even if painting is performed by lining construction, iron rust will spread from the pinhole part and new iron rust will occur. May be easy. As a result, the inner wall surface has to be painted every time iron rust occurs, which is very costly. In addition, the conventional rust prevention method for pipes and the like has various problems such as harmfulness and necessity of specialized operation.

The present invention is to solve the above-mentioned problems of the conventional method for coating the inner wall surface of a pipe or the like, and to easily prevent rusting in the entire pipe after sandblast cleaning and before coating lining. Therefore, it is an object of the present invention to prevent corrosion by using a tannic acid aqueous solution containing a water-soluble polymer that is harmless and easily penetrates into water.

[0005]

In order to solve the above-mentioned problems, the inner wall surface coating method for pipes and the like of the present invention is carried out by sand blast cleaning as usual, followed by washing with water, vinyl chloride which is harmless and easily penetrates into water, Easily prevent corrosion of the entire pipe by filling and applying a tannic acid solution containing a water-soluble polymer such as acrylic and saran, removing the tannic acid solution containing a water-soluble polymer described above, and after drying, apply a coating lining. It is characterized by.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the invention will be described based on Examples. In sandblast cleaning,
A high-speed air stream mixed with an appropriate amount of silica sand is flowed from the tip to the end so that iron rust is removed from the inside of the pipe so that it spreads throughout the pipe. Further, especially in the joint portion, since it is difficult for the silica sand to spread, the high-speed airflow is sent from the direction opposite to the direction in which the silica sand has flowed, that is, the end pipe mouth to the tip pipe mouth, so that the silica sand can reach every corner surely.

After iron rust is removed, in order to remove silica sand, water is washed by flowing water so as to reach the entire pipe from the front pipe end to the end pipe mouth. After the silica sand is removed, the end tube mouth is closed and a tannic acid solution containing a water-soluble polymer such as vinyl chloride, acrylic and saran is filled from the tip tube mouth until the inside of the tube is full, and the inner surface of the tube is evenly applied. To do.
At this time, the water used for washing may remain in the pipe.
5 minutes to 2 for the tannic acid solution to penetrate the entire tube
It is advisable to leave it filled for 0 minutes. Further, in order to sufficiently permeate, it is preferable to block the tip tube opening and the end tube opening and vibrate. After filling and leaving, the excess tannic acid solution other than the tannic acid molecule that has reacted with the iron molecule on the inner wall of the tube is removed by releasing the blockage of the terminal tube mouth. At this time, the removed tannic acid solution can be reused. Then, the entire tube is dried. It is advisable to send warm air of 10 ° C. to 50 ° C. so as to spread all over the tube to dry it for 10 to 30 minutes until the entire tube is free of water.

In the coating lining work, the paint poured into the pipe is pressure-fed by a high-pressure gas such as nitrogen gas, and is pressed against the inner wall surface of the pipe body or the inner wall surface of the joint portion to spread and spread throughout the pipe. Then, while the applied paint is in a semi-dried state, high-pressure air is applied from the direction in which the paint is applied, that is, from the tip end port to the end end port, and from the opposite direction, that is, from the end end port to the tip end port. Send in and spread the extra paint that has dripped especially on the non-painted part of the joint while surely painting every corner.

[0009]

INDUSTRIAL APPLICABILITY The method for coating an inner wall surface of a pipe according to the present invention has the following effects. After sandblast cleaning, tannic acid solution, which is known to convert to tannin iron that is water-soluble and adheres to iron rust and is stable, is used for rust prevention. Not only can you prevent the rust from spreading in the pinholes by coating the rust on the pinholes, but you can also easily penetrate the joints where silica sand is difficult to spread. Since such a water-soluble polymer is blended, it has an effect that rust is not generated for a longer period of time than the tannic acid aqueous solution. Further, from the above effect, the dry coating film surface after the tannic acid solution coating is smooth and the fluidity of the tube thickening coating is improved, the number of times of coating is reduced, and since the tannic acid solution can be reused, It costs less when viewed over a longer period than conventional methods. In addition, since tannic acid is harmless and can be rust-proofed, there is an effect that the need for specialized operation is eliminated.

Claims (5)

[Claims] 1. After sandblasting the inside of the pipe, it is washed with water, and a tannic acid solution containing a water-soluble polymer such as vinyl chloride, which is harmless and easily penetrates into water, is filled and applied, and the tannic acid solution is removed and dried. , A method of painting the inner wall surface of pipes, etc., where the coating lining work is performed. 2. The method for coating an inner wall surface of a pipe or the like according to claim 1, wherein the tannic acid is vibrated when the tannic acid solution containing the water-soluble polymer is filled. 3. The method for coating an inner wall surface of a pipe or the like according to claim 1 or 2, wherein the time for filling the tannic acid solution containing the water-soluble polymer is 5 to 20 minutes. 4. The method for coating an inner wall surface of a pipe or the like according to claim 1, wherein hot air is flowed throughout the pipe body during drying. 5. The method for coating an inner wall surface of a pipe or the like according to claim 1, wherein the drying time is 10 minutes to 30 minutes.