JP2005090581A - Steel pipe repairing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel pipe repairing method capable of preventing deterioration of strength of a steel pipe by stopping progress of rust in the steel pipe. <P>SOLUTION: A flexible cylindrical lining material 5A impregnated or coated with a uncured curable resin is arranged in the steel pipe 1, and the cylindrical lining material 5A is pushed to the inner wall of the steel pipe 1, and the hardening resin is hardened to perform the cylindrical lining to the inner surface of the steel pipe 1. In this steel pipe repairing method, when arranging the cylindrical lining material 5A in the steel pipe 1, a rust preventing agent 4 is interposed between the inner wall of the steel pipe 1 and the cylindrical lining material 5A to form a rust preventing agent layer 4a to prevent the generation of rust and progress thereof in the steel pipe 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for repairing a steel pipe, and more particularly to a repair method suitable for repairing a steel pipe as a protective pipe buried in the ground by non-cutting.

  2. Description of the Related Art Conventionally, communication cables such as power lines and telephone lines are widely housed and installed in protective tubes buried in the ground. However, since a steel pipe is generally used as the protective tube, although the electromagnetic shielding effect is excellent, there is a problem that the protective tube is deteriorated and damaged by rust or the like due to aging.

  As repair means when such a problem occurs, non-open repair such as open repair in which a buried portion is cut and a protective pipe (hereinafter referred to as a steel pipe) is replaced, and coating lining and inversion forming lining are known. In the repair means, the excavation repair for exchanging and replacing the steel pipe is troublesome repair work, especially in urban areas, there are many other enterprises buried, and it can not be easily replaced, and it takes a lot of days. Requires labor. In contrast, non-open repair such as coating lining and reverse forming lining is easier to repair than open repair and can be done in a short period of time. Therefore, non-open repair is now widely used as a repair method for steel pipes. doing.

  And among the non-open cut repairs, from the viewpoint of the strength after repair, a reversal lining mainly comprising a method using a flexible cylindrical lining material impregnated or coated with a curable resin is employed. ing.

  In such a method, a cylindrical lining material formed of a flexible material impregnated or coated with a thermosetting resin, a photocurable resin, or a room temperature curable resin is placed in a protective tube, that is, a steel tube, and this cylindrical shape is arranged. Water pressure or air pressure is applied to the lining material to inflate it and press it against the inner wall surface of the steel pipe. By passing hot water, steam, or ultraviolet rays into the cylindrical lining material, the curable resin is cured. Lining is performed (see, for example, Patent Document 1).

  As a method of arranging the lining material in the steel pipe, there are a construction method in which the lining material is pulled and pulled on the tip side, and a construction method in which the lining material is advanced while being reversed from the side where the lining material is inserted into the steel pipe. Are known.

When repairing a steel pipe by non-cutting such as placing a lining material in such a steel pipe, the repair is performed by checking the state in the steel pipe visually or with a TV camera. If there is rust or foreign matter, etc. Repair after removing rust and foreign matters by cleansing with a brush or high pressure water.
Japanese Patent Publication No. 7-4853

  According to the steel pipe repair method described above, the cylindrical lining material is pressed against the inner wall surface of the steel pipe, but the gap between the inner wall surface of the steel pipe and the cylindrical lining material cannot be completely eliminated. When there is damage such as a crack or a small hole, air or water enters the gap from there, and rust may be generated and proceed. When the rust of the steel pipe progresses, the steel pipe becomes brittle, and its strength is vigorously applied to the tubular lining material. Therefore, to obtain strength, it is required to increase the thickness of the cylindrical lining material. When the thickness of the cylindrical lining material is increased, the inner diameter of the steel pipe is reduced accordingly, and the power line, telephone line There is a problem that the insertion of the communication cable is troublesome and the cost is increased.

  An object of the present invention is to provide a steel pipe repairing method that can prevent the progress of rust of a steel pipe and prevent the deterioration of the strength of the steel pipe.

  In order to achieve the above object, the invention described in claim 1 is characterized in that a flexible tubular lining material impregnated or coated with an uncured curable resin is disposed in a steel pipe, and the tubular lining material is disposed. In the steel pipe repairing method in which the steel pipe is cured from the inner surface by pressing the inner wall of the steel pipe and curing the curable resin, when the cylindrical lining material is disposed in the steel pipe, the inner wall of the steel pipe and the cylindrical lining material A rust preventive layer is formed by interposing a rust preventive agent therebetween.

  The invention according to claim 2 is the inorganic rust-proof coating composition according to claim 1, wherein the rust inhibitor includes a powdery basic compound and is adjusted to pH 8.0 to 13.0. It is characterized by.

  In the invention described in claim 3, the rust preventive agent described in claim 1 is prepared by adding an inorganic rust preventive coating composition containing a powdery basic compound to a viscous holding material, and having a pH of 8.0-13. .. adjusted to 0.0.

  The invention described in claim 4 is characterized in that the holding material according to claim 3 is a lubricant.

  The invention according to claim 5 is characterized in that the rust preventive agent according to claim 2, 3 or 4 contains zinc powder.

  According to the invention described in claim 1, a flexible tubular lining material impregnated or coated with an uncured curable resin is disposed in the steel pipe, and the tubular lining material is pressed against the inner wall of the steel pipe, In the steel pipe repairing method in which the curable resin is cured and the steel pipe is cylindrically lined from the inner surface, when the cylindrical lining material is disposed in the steel pipe, a rust inhibitor is provided between the inner wall of the steel pipe and the cylindrical lining material. By forming the rust preventive layer with the rust preventive agent layer formed between the inner wall surface of the steel pipe and the cylindrical lining material, the gap between the inner wall surface of the steel pipe and the cylindrical lining material is filled, and The steel pipe has damage such as cracks and small holes, and even if air or water enters the cracks or small holes, the rust preventive layer can prevent the rust generation and progression of the steel pipe. Can prevent the life of the steel pipe It will be possible. This eliminates the need for the tubular lining material to reinforce the steel pipe and the self-supporting nature of the rehabilitation pipe, so that the membrane pressure of the cylindrical lining material can be reduced, and the tubular lining material film Since the thickness can be reduced, the inner diameter of the steel pipe can be increased correspondingly, and the cost can be reduced.

  According to the invention described in claim 2, since the rust preventive agent is an inorganic rust preventive coating composition containing a powdery basic compound and adjusted to pH 8.0 to 13.0, the inner periphery of the steel pipe The surface is kept alkaline and passivated, that is, a passivated layer of iron oxide is formed on the inner peripheral surface of the steel pipe to be in a stable state, and the generation and progress of rust can be prevented.

  According to the invention described in claim 3, the rust preventive agent is adjusted to pH 8.0 to 13.0 by adding an inorganic rust preventive coating composition containing a powdery basic compound to a viscous holding material. As a result, the inner peripheral surface of the steel pipe is kept alkaline and passivated, that is, a passive layer of iron oxide is formed on the inner peripheral surface of the steel pipe and becomes stable. Since the inorganic anticorrosive coating composition is added to the viscous holding material, it can be easily adhered to the inner wall surface of the steel pipe, and the anticorrosion is provided between the inner wall of the steel pipe and the cylindrical lining material. An antirust layer can be formed by interposing an agent.

  Since the invention according to claim 4 uses the holding material according to claim 3 as a lubricant, the inorganic rust-proof coating composition is used as a lubricant used when the lining material is pulled into the steel pipe. By using a rust inhibitor added to the lubricant, there is no need to take special measures to interpose the rust inhibitor between the inner wall of the steel pipe and the tubular lining material. By drawing the lining material, it is possible to form a rust preventive layer by interposing a rust preventive agent between the inner wall of the steel pipe and the cylindrical lining material.

  According to invention of Claim 5, since the said rust preventive agent contains zinc powder, it will exhibit an electrocorrosion-proof characteristic and can prevent the corrosion of a steel pipe more effectively.

The best mode for carrying out the steel pipe repairing method according to the present invention will be described below.
In the steel pipe repair method according to the present invention, a flexible cylindrical lining material impregnated or coated with an uncured curable resin is disposed in the steel pipe, the cylindrical lining material is pressed against the inner wall of the steel pipe, and the hardening is performed. In the steel pipe repair method in which the tubular resin is cured from the inner surface by hardening the heat-resistant resin, a rust inhibitor is interposed between the inner wall of the steel pipe and the tubular lining material when the tubular lining material is placed in the steel pipe. And forming a rust preventive agent layer.

  The cylindrical lining material has a three-layer structure of an impermeable inner film layer, a resin-absorbing inner layer impregnated with a curable resin, and an impermeable outer film layer. Examples of the curable resin include a thermosetting resin, a photocurable resin, and a room temperature curable resin, which are impregnated with felt to form a resin-absorbing inner layer. Further, a polyurethane film is used as the impermeable inner film layer, and a polyethylene film is used as the impermeable outer film layer. However, the present invention is not limited to this.

  Further, when the tubular lining material is disposed in the steel pipe, a rust preventive layer is formed by interposing a rust preventive agent between the inner wall of the steel pipe and the cylindrical lining material. In the rust preventive agent, an inorganic rust preventive coating composition containing a powdery basic compound and adjusted to pH 8.0 to 13.0 is used.

  Powdered basic compounds include powders such as magnesium hydroxide, basic magnesium carbonate, calcium hydroxide, barium hydroxide, barium metaborate, borax, Portland cement, alumina cement, blast furnace cement, etc. The smaller the diameter, the better.

  The inorganic anticorrosive coating composition containing the powdery basic compound was adjusted to pH 8.0 to 13.0 because the iron oxide passive layer was in the range of pH 8.0 to 13.0. This is because it is formed and becomes stable, and corrosion does not proceed.

  From the viewpoint of workability, the rust inhibitor is an inorganic rust coating composition containing a powdery basic compound added to a viscous holding material and adjusted to pH 8.0 to 13.0. preferable. Further, the holding material may be a lubricant. When the retaining material is a lubricant, the rust preventive agent is used as a lubricant when the lining material is drawn into the steel pipe by a conventional method, so that the rust preventive agent is interposed between the steel pipe inner wall and the cylindrical lining material. A rust layer can be formed. The lubricant is a composite such as a high molecular weight polymer material, and has a viscosity of 600 mP · S to 2000 mP · S in a substantially neutral range.

  Moreover, the said rust preventive agent may contain zinc powder. The anticorrosive property is exhibited, and corrosion of the steel pipe can be more effectively prevented.

  In the steel pipe repair method according to the present invention, when the tubular lining material is disposed in the steel pipe, the rust preventive layer is formed by interposing the rust preventive agent between the steel pipe inner wall and the cylindrical lining material. In the means for forming the rust preventive layer by interposing the rust preventive agent between the steel pipe inner wall and the cylindrical lining material, the steel pipe inner wall surface is drawn before drawing the cylindrical lining material into the steel pipe. A rust preventive agent may be applied to the tube, and then the cylindrical lining material may be drawn in. Alternatively, the rust preventive agent may be applied to the inner wall surface of the steel pipe while drawing the cylindrical lining material into the steel pipe. By any means, it is necessary to reliably apply the rust preventive agent so that no uncoated portion remains on the inner wall surface of the steel pipe.

Next, an embodiment of the steel pipe repair method according to the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of a steel pipe repair method according to the present invention. In the drawings, reference numeral 1 denotes a steel pipe buried in the ground 2 and is divided by manholes 3 standing vertically at predetermined intervals. In repairing the steel pipe 1, after cleaning the inside of the steel pipe 1 by removing rust and foreign matters by an appropriate means, first, the rust preventive agent 4 is placed in one opening of the steel pipe 1 partitioned by the manhole 3. Fill up. In this case, the rust preventive agent 4 is used in which an inorganic rust preventive coating composition containing a powdery basic compound is added to a lubricant.

  Next, a brush member 6 formed of a sponge or the like that is in sliding contact with the entire inner wall surface of the steel pipe 1 is provided at the tip of the cylindrical lining material 5A, and the brush member 6 is formed on the steel pipe 1 filled with the rust inhibitor 4. The steel pipe 1 is inserted into one opening and pulled by the pulling rope 7 toward the other opening. Thereby, the rust preventive agent 4 filled in one opening of the steel pipe 1 is applied to the inner wall surface of the steel pipe 1 by the moving brush member 6, and the cylindrical lining material 5A is applied to the rust preventive agent 4. Is pulled from behind the brush member 6 into the steel pipe 1 coated on the inner wall surface. At this time, since the inorganic rust preventive coating composition containing the powdery basic compound is added to the lubricant, the cylindrical lining material 5A is drawn smoothly.

  In this way, the tubular lining material 5A drawn into the steel pipe 1 is inflated by applying water pressure or air pressure, and pressed against the inner wall surface of the steel pipe 1 to prevent it between the inner wall surface of the steel pipe 1 and the cylindrical lining material 5A. The rust agent layer 4a is formed. At this time, even if uncoated rust preventive agent 4 remains on the inner wall surface of the steel pipe 1, if it is slight, the inner wall surface of the steel pipe 1 is pressed against the inner wall surface of the steel pipe 1 by the cylindrical lining material 5 </ b> A. The rust preventive agent 4 is rolled to fill the uncoated portion, and the rust preventive agent layer 4a can be reliably formed between the inner wall surface of the steel pipe 1 and the cylindrical lining material 5A. Thereafter, high temperature hot water and steam are passed through the cylindrical lining material 5A, or ultraviolet rays are irradiated to cure the curable resin impregnated in the cylindrical lining material 5A, and the repair of the steel pipe 1 is completed.

  FIG. 2 shows a second embodiment of the steel pipe repair method according to the present invention. In this example, the tubular lining material 5B is drawn into the steel pipe 1 by inserting the cylindrical lining material 5B into the steel pipe 1. This is performed by a method of advancing the tubular lining material 5B from the side while inverting it. First, as in the first embodiment, the rust preventive agent 4 is filled into one opening of the steel pipe 1 partitioned by the manhole 3. In this case, as the rust preventive agent 4, an inorganic rust preventive coating composition containing a powdery basic compound is added to a viscous holding material.

  Next, the tubular lining material 5 </ b> B is advanced and retracted while being reversed from the side of insertion into the steel pipe 1. Thereby, the rust preventive agent 4 filled in one opening of the steel pipe 1 is guided between the inner wall surface of the steel pipe 1 and the cylindrical lining material 5B by the cylindrical lining material 5B that moves forward while reversing. The rust preventive agent layer 4a is formed between the cylindrical lining material 5B that is reversed and pressed against the inner wall surface of the steel pipe 1 and the inner wall surface of the steel pipe 1.

  Thereafter, high temperature hot water and steam are passed through the cylindrical lining material 5B, or ultraviolet rays are irradiated to cure the curable resin impregnated in the cylindrical lining material 5B, and the repair of the steel pipe 1 is completed.

  FIG. 3 shows a third embodiment of the steel pipe repairing method according to the present invention. In this example as well, the tubular lining material 5B is drawn into the steel pipe 1 in the same manner as the second embodiment. This is performed by a method of moving the tubular lining material 5B forward from the side where it is inserted into the steel pipe 1 while being reversed. In this example, the rust preventive agent 4 is filled in the cylindrical lining material 5B before reversal (the surface that is reversed and becomes the outer peripheral surface is inside). In this case, as the rust preventive agent 4, an inorganic rust preventive coating composition containing a powdery basic compound is added to a viscous holding material.

  Next, the tubular lining material 5 </ b> B is advanced and retracted while being reversed from the side of insertion into the steel pipe 1. Thereby, the outer peripheral surface of the said cylindrical lining material 5B is reversed in the state which the rust preventive agent 4 with which it filled in the cylindrical lining material 5B reversed and adhered to the outer peripheral surface of the cylindrical lining material 5B used as the outer side. Thus, the inner wall surface of the steel pipe 1 is pressed against the inner wall surface, thereby forming a rust inhibitor layer 4a between the tubular lining material 5B and the inner wall surface of the steel pipe 1.

  Thereafter, high temperature hot water and steam are passed through the cylindrical lining material 5B, or ultraviolet rays are irradiated to cure the curable resin impregnated in the cylindrical lining material 5B, and the repair of the steel pipe 1 is completed.

  In addition, the steel pipe repair method which concerns on this invention is not limited to the said Example. In said 1st, 2nd and 3rd Example, after hardening the curable resin which impregnated the cylindrical lining material, you may remove the impermeable inner film layer of a cylindrical lining material. Moreover, in the said Example, although the steel pipe to repair is an underground burial pipe, it is not limited to an underground burial pipe, Moreover, it is limited to the protection pipe | tube which accommodates communication cables, such as a power line and a telephone line. It is not a thing.

Explanatory drawing which shows 1st Example of the steel pipe repair method which concerns on this invention. Explanatory drawing which shows 2nd Example of the steel pipe repair method which concerns on this invention. Explanatory drawing which shows 3rd Example of the steel pipe repair method which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel pipe 2 Ground 3 Manhole 4 Rust inhibitor 4a Rust preventive layer 5A, 5B Cylindrical lining material 6 Brush member 7 Tow rope

Claims (5)

A flexible cylindrical lining material impregnated or coated with an uncured curable resin is placed in the steel pipe, the cylindrical lining material is pressed against the inner wall of the steel pipe, the curable resin is cured, and the steel pipe is In the pipe repair method for tubular lining, when the tubular lining material is disposed in the steel pipe, a rust preventive layer is formed by interposing a rust preventive agent between the steel pipe inner wall and the cylindrical lining material. Steel pipe repair method characterized by The method of repairing a steel pipe according to claim 1, wherein the rust inhibitor is an inorganic rust preventive coating composition containing a powdery basic compound and adjusted to pH 8.0 to 13.0. The said rust preventive agent is an inorganic rust preventive coating composition containing a powdery basic compound added to a viscous holding material and adjusted to pH 8.0 to 13.0. The steel pipe repair method according to 1. The steel pipe repair method according to claim 3, wherein the holding material is a lubricant. The steel pipe repair method according to claim 2, 3 or 4, wherein the rust preventive agent contains zinc powder.

Images