JP2002022093A - Repair construction method for anticorrosion pipe line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce labor burden, simply and surely repair, and improve mechanical durability. SOLUTION: An anticorrosion layer 2B provided on a metal pipe 2 surface is ground in a part P to be repaired of a metal pipe 2, a coating member 1 being composed of a heat-melting material with a recessed space part 1A formed in a face opposite to the exposed anticorrosion layer 2B, and being formed into such a dimension as forming a clearance S in a space with a side inside of the anticorrosion layer 2B with the exposed one part is mounted on the exposed anticorrosion layer 2B, and the coating member 1 is heated by an ultrasonic wave, so that the outer circumferential edge of the recessed space and the anticorrosion layer 2B oppositely abutting thereon are mutually molten and integrated together. After the melt-fitting, the clearance S is filled with an airtight survey agent DL and the coating member 1 is pressurized from the top so that the state of the airtight survey agent DL is monitored and the melting state of the coating member 1 and the anticorrosion layer 2B is determined.

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 an anticorrosion pipe, and more particularly to a method for repairing a defective portion of the anticorrosion coating layer in a metal pipe having an anticorrosion coating layer formed on an outer surface.

[0002]

2. Description of the Related Art In some cases, a metal pipe such as a cast iron pipe is used as a pipe material used for moving a fluid such as a gas. Metal pipes are used by being buried underground.However, there is a risk of corrosion over time due to contact with moisture in the soil. In some cases, an anticorrosion treatment is performed by providing an undercoat layer using a waterproof material such as butyl rubber on the contact side.

[0003]

When the ground where the metal pipe, which has been subjected to the anticorrosion treatment by the coating layer using the resin or the rubber or the like, is buried by a construction machine or a tool, is located on the outer surface. The coating layer may peel off or break due to contact with construction machines or tools. For this reason,
If a damaged portion such as a peeled portion or a defective portion in the coating layer is left as it is, corrosion of the metal tube proceeds due to moisture in the soil, and a problem such as gas leakage occurs. Conventionally, when the above-mentioned damaged position is found, repair work has been performed by exposing the entire pipe and winding an anticorrosion tape or the like. However, in such an operation, it is necessary to expose the entire circumference of the pipeline in order to wind the tape irrespective of the pipeline diameter, which not only increases the labor burden for ancillary work such as excavation work, but also increases the tape. This is a very inefficient operation because it is necessary to tightly and tightly wind the wrapping. It is important not only to wind the tape but also to prevent the tape from peeling off using an adhesive or the like, but there is a possibility that the tape will peel off due to aging of the adhesive itself. For this reason, it may be necessary to monitor the repair location, and this may impose a new labor burden of maintenance. As an anti-corrosion method, there is an anti-corrosion method different from the above-described method, but in the case of a damage form that induces crevice corrosion, it is not so effective, and an incomplete tape without airtightness is wound. There is also a possibility that the anticorrosion effect cannot be expected.

Depending on the size of the portion to be repaired, the surface of the portion to be repaired may be coated to enhance the corrosion protection performance, and the surface may be finished so as to be flush with the surface of the corrosion-resistant layer near the portion to be repaired. . In this case, for example, a concave portion on the surface of the repair tape is filled with the coating material. However, if the surface of the repair tape is filled or coated with a coating material to cover the tape surface and the surface is made even, the material used for the surface finishing may be released from the tape surface. The problem of aging in places remains. On the other hand, when repairing a repair target location, the work is often completed only by wrapping the above-mentioned repair tape, and it is not possible to confirm whether gas leakage from the repair location has completely stopped. Not much is done at the moment. In other words, it is assumed that wrapping the repair tape itself completely shuts off gas leakage, and leakage monitoring during repair is often not performed for the purpose of shortening the working time. Become.

SUMMARY OF THE INVENTION An object of the present invention is to reduce the labor burden when repairing is required in a relatively large area in view of the above-mentioned problems in conventional pipelines, particularly in metal pipes subjected to anticorrosion treatment. To check the airtight condition after repairing, to make repairs easier and more reliable, and to improve the mechanical durability by increasing the peel strength of the surface finishing material used for surface finishing It is an object of the present invention to provide a method of repairing an anticorrosion pipe which can be performed.

[0006]

In order to achieve this object, an invention according to claim 1 is a repair method for a metal pipe buried in the soil and having an outer surface provided with an anticorrosion coating layer. In the repair target portion of the metal pipe, the anticorrosion layer provided on the surface of the metal pipe is ground to expose a part of the anticorrosion layer to the outside, and on a surface opposed to the exposed anticorrosion layer. It is made of a heat-sealable material having a concave space,
The covering member formed in such a size that a gap can be formed between the part and the inner surface of the side of the anticorrosion layer is placed on the exposed anticorrosion layer, and the coating member is heated by ultrasonic heating. By doing so, the outer peripheral edge of the concave space portion and the anticorrosion layer, which is in abutting contact with each other, are fused and integrated with each other. The state of fusion between the covering member and the anticorrosion layer is determined by monitoring a change in the state of the hermetic exploration agent by pressing from above.

According to a second aspect of the present invention, in the method for repairing an anticorrosion pipe according to the first aspect, the covering member has the concave space portion on a lower surface, and a folded piece is provided on a side portion on a surface opposite to the concave space portion. A locking portion is provided, which locks a part of the filled finishing material when the upper surface of the covering member is filled with the finishing material after checking the state change of the hermetic exploration agent performed after the fusion. To prevent peeling.

According to a third aspect of the present invention, in the method for repairing an anticorrosion pipe according to the second aspect, the covering member is thicker at a central portion of the upper surface than at other portions. .

[0009]

According to the first and third aspects of the present invention, a coating member having a concave space portion provided on a side facing the anticorrosion layer with respect to the anticorrosion layer partially ground and exposed to the outside is provided. By mounting and ultrasonic heating, the outer peripheral portion of the concave space and the exposed anticorrosion layer can be fused and integrated. In addition, even when a part of the anticorrosion layer provided on the metal tube side is spouted due to heat of fusion at the time of fusion, the ejected material can be accommodated in the concave space portion, so that the covering member may be lifted by the ejected material. The fusion can be performed without any problems. Furthermore, after the fusion, the space between the side surface of the covering member and the inner side surface of the anticorrosion layer is filled with the hermetic exploration agent, and the state of the hermetic exploration agent is utilized by pressing the covering member from above. Thus, the fused state can be determined. As a result, since the fusion between the covering member and the anticorrosion layer can be monitored, the fusion can be performed more reliably. In particular, at the time of fusion, even in a situation where the central portion of the coating member is more likely to melt than the other portion due to the heating time, the original shape of the coating member can be maintained until the other portion is melted. The fusion between the side surface and the inner surface of the anticorrosion layer can be ensured.

According to the second aspect of the present invention, since the material used for surface finishing can be locked by using the locking portion provided on the upper surface of the covering member to prevent peeling, the material used for surface finishing can be prevented. Can be increased in mechanical peel strength to improve durability.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a covering member 1 corresponding to a repair member used in a repair method according to an embodiment of the present invention. In FIG. 1, a covering member 1 is a molded component using a heat-sealable material made of polyethylene and having a downwardly facing cap shape. In this embodiment, when the size of the repair target portion is in a range of about 16φ, the outer dimension is set to 22φ which can cover the range of the repair target portion. The lower surface of the covering member 1 is formed with a concave space portion (hereinafter referred to as a concave space portion) 1A, and a lower outer surface of a wall portion located on the outer peripheral portion of the space portion 1A is provided with an anticorrosion described later. The inclined surface 1A1 forms a fusion surface with the layer.

At a position above the wall located on the outer peripheral portion of the covering member 1, there is provided a hook-shaped locking portion 1B extending upward and having its upper end bent toward the center. Further, a thick portion 1C having a greater thickness than other portions is provided at the center of the upper surface. The locking portion 1B is a portion having a hook-like upper end that can lock a part of the material filled on the upper surface to prevent peeling, and the thick portion 1C has a longer heating time. In consideration of the fact that the melting at the center is more advanced than at the other part, the thickness at the center is maintained until the melting at the other part is completed, and the fusion at the other part is performed. Is a part for preventing incompleteness. That is, in the case of a disk shape like the covering member 1 shown in the embodiment, if the heating time by the ultrasonic heating becomes long when the ultrasonic wave is input to the covering member, the ultrasonic vibration is concentrated in the central portion, and in this portion. Melting is easier to progress than other parts. For this reason, if thermal deformation or chipping occurs at the central portion, fusion at other portions becomes impossible, and until the melting at other portions is completed, the original shape as the covering member 1 is obtained. Is maintained to promote the heat fusion in other parts, thereby preventing the occurrence of defective fusion. Such a thick portion 1C is installed depending on the size of the covering member 1 that affects the length of the heating time. However, even if the thickness is small, if the heating time is long, As shown in FIG. 5, the provision at the central portion can prevent poor fusion at the fused portion other than the central portion by the above-described operation.

The thick portion 1C can be pressed from above, and when pressed, the covering member 1 can be bent downward, thereby contracting and deforming the concave space portion 1A. Can be. In addition, this thick part 1C is
In addition to the configuration shown in the embodiment, a disk-shaped one having a relatively small size can be used. For example, as shown in FIG. 5, the gradient surface 1 shown in FIG.
Even if it is a mere cap-like structure without A1 provided, the same action as in the above case can be obtained by providing it at the center.

In this embodiment, repair is performed by the following procedure using the covering member 1 having the above configuration. (1) FIG. 2 shows a metal pipe 2 having a repair target portion P. In the same figure, a rubber-based undercoat layer 2A using butyl rubber or the like, and a Anticorrosion coating layers 2B, 2C using polyethylene resin and polypropylene resin sequentially laminated on the upper surface
Is provided. The damaged portion P is formed by the anticorrosion coating layer 2
Parts B and 2C are parts where the parts are missing or damaged, and the parts are ground by a reamer with a stopper (not shown). In this embodiment, the covering member 1
Of the outer peripheral wall portion located in the concave space portion 1A of the covering member 1 and the inside of the ground surface are ground. It has become. As will be described later, the gap S is filled with an airtight exploration agent used for determining the fusion state. The reamer with the stopper can define a grinding depth, and the grinding depth is set to a depth at which the rubber-based undercoat layer 2A is exposed. The portion ground by the reamer with the stopper has a sloped surface inside the ground surface according to the edge angle of the reamer.

(2) After grinding, the covering member 1 is placed on the ground surface and fused. The covering member 1 is placed in a state where the contact surfaces are almost aligned by placing the slope 1A1 of the outer peripheral wall of the concave space 1A located on the lower surface on the slope of the grinding surface. The covering member 1 is placed on the grinding surface in a state where a gap S is formed between the outer peripheral wall portion outer surface of the concave space portion 1A and the inner side of the grinding surface. The covering member 1 placed on the ground surface is ultrasonically heated by an ultrasonic welding machine (not shown) for about one to several minutes, and the slope surface and the ground surface on the outer peripheral wall of the concave space 1A are fused. You. At the time of fusion, the central portion of the covering member 1 is intensively heated.
Is provided, the thermal deformation or loss at the central portion is prevented until the melting progresses at other portions. At the time of fusion between the covering member 1 and the ground surface, the temperature of the rubber-based undercoat layer 2A located on the surface of the metal tube 2 may rise due to heat conduction through the metal tube 2 and may be melted. When a part of the rubber is melted, the ejected material (for convenience, indicated by reference numeral BO in FIG. 2) is stored in the concave space portion 1A of the covering member 1, so that the covering material 1 may be pushed up by the ejected material. Absent. Thereby, since the covering member 1 does not rise from the fusion surface, fusion bonding can be performed reliably.

(3) When the ultrasonic heating of the covering member 1 is completed, the gap S existing between the inside of the ground surface and the outside surface of the outer peripheral wall of the covering member 1 is filled with the hermetic exploration agent DL and fused. The state is determined. In this embodiment, the hermetic filler DL
As such, a foamable material such as soapy water is used, and the degree of foaming due to gas intrusion can be monitored. FIG. 3 is a diagram showing a state in which the fusion state is being determined. In FIG. 3, the thick portion 1C of the covering member 1 is pressed from above (the pressing force in the direction indicated by the symbol F in FIG. 3). Is deflected downward. As a result, the inside pressure of the concave space portion 1A is increased by contraction deformation. At this time, when the fusion state is incomplete, the air from the concave space portion 1A enters the hermetic exploration agent DL via the space portion present on the fusion surface, so that the hermetic exploration agent DL foams. become. This makes it possible to externally confirm that the fusion state is incomplete, so that the ultrasonic heating can be repeated again to bring the fusion state to a complete state.

(4) When the fusion state determination shown in FIG. 3 is completed and the fusion state is complete, the upper surface of the covering member 1 is finished as shown in FIG. In FIG.
The upper surface of the covering member 1 is filled with a surface finishing material 3 using a curable resin or caulking rubber. A part of the finishing material 3 is locked by the locking portion 1B of the covering member 1, and the peel strength is increased. Since the finishing material 3 penetrates into and fills the gap S filled with the hermetic exploration agent DL, all spaces are filled from the fusion surface to the upper surface of the covering member 1, and the surface is repaired. Anticorrosion layer 2C near target area
And are formed flush.

According to the present embodiment, the inclined surface 1A1 is provided on the outer peripheral wall of the concave space portion 1A, and the inclined surface 1A1 is easily aligned with the inclined surface of the ground surface. The area of the surface can be easily secured.

[0019]

As is clear from the above embodiments,
According to the first and third aspects of the present invention, a covering member having a concave space portion on a side facing the anticorrosion layer is mounted on the anticorrosion layer which is partially ground and exposed to the outside. The outer peripheral portion of the concave space portion and the anticorrosion layer can be fused by ultrasonic heating by a simple operation of merely placing. In addition, even when a part of the anticorrosion layer provided on the metal tube side is spouted due to heat of fusion at the time of fusion, the ejected material can be accommodated in the concave space portion, so that the covering member may be lifted by the ejected material. The fusion can be performed without any problems. Furthermore, after the fusion, the space between the side surface of the covering member and the inner side surface of the anticorrosion layer is filled with the hermetic exploration agent, and the state of the hermetic exploration agent is utilized by pressing the covering member from above. Thus, the fused state can be determined. As a result, since the fusion between the covering member and the anticorrosion layer can be monitored, the fusion state can be performed more reliably. In particular, at the time of fusion, even in a situation where the central portion of the coating member is more likely to melt than the other portion due to the heating time, the original shape of the coating member can be maintained until the other portion is melted. The fusion between the side surface and the inner surface of the anticorrosion layer can be ensured.

According to the second aspect of the present invention, since the material used for surface finishing can be locked by using the locking portion provided on the upper surface of the covering member to prevent peeling, the material can be used for surface finishing. The mechanical peel strength of the material to be used can be increased to improve the durability.

[Brief description of the drawings]

FIG. 1 is a view for explaining a configuration of a covering member used in a repair method according to an embodiment of the present invention.

FIG. 2 is a view for explaining one step of a repair method according to an embodiment of the present invention.

FIG. 3 is a view for explaining another step of the repair method according to the embodiment of the present invention.

FIG. 4 is a view for explaining the final step of the repair method according to the embodiment of the present invention.

FIG. 5 is a view showing another example of the covering member shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Covering member 1A Concave space part 1A1 Slope surface 1C Thick part 2 Metal tube 2A Rubber-based undercoat layer 2B Polyethylene layer which is one of anticorrosion layers 2C Polypropylene layer which is another one of anticorrosion layers P Repair target place P1 Ground location BO Ejected material DL Hermetic agent S Clearance gap filled with hermetic agent

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshiyuki Koide 1-17-114, Sakaemachi, Kawaguchi-shi, Saitama F-term in Sanko Gas Seiki Co., Ltd. (Reference) 3H024 EA03 EC10 ED04 EE03 3H025 EA01 EB02 EB25 EC06 ED01 EE05

Claims (3)

[Claims] 1. A repair method for a metal pipe buried in the soil and having an anticorrosion coating layer formed on an outer surface thereof, wherein the repair method is provided on a surface of the metal pipe at a repair target location of the metal pipe. The anticorrosion layer is ground to expose a part of the anticorrosion layer to the outside, and is made of a heat-sealable material having a concave space on a surface facing the exposed anticorrosion layer, and the part is The covering member formed in such a size that a gap can be formed between the exposed anticorrosion layer and the inner surface of the side portion is placed on the exposed corrosion protection layer, and the covering member is ultrasonically heated. The outer peripheral edge of the concave space portion and the anticorrosive layer that is in contact with and opposed to each other are fused and integrated, and after fusion, the gap is filled with an airtight exploration agent and the covering member is pressed from above. Monitoring the state change of the hermetic Repairing method of anticorrosive treatment conduit, characterized in that to determine the fused state between members and the corrosion layer. 2. The method for repairing an anticorrosion pipe according to claim 1, wherein the covering member has the concave space portion on a lower surface, and a locking portion made of a folded piece is provided on a side portion on a surface opposite to the concave space portion. It is provided that when a finish is filled on the upper surface of the covering member after the state change of the hermetic exploration agent performed after the fusion is performed, a part of the finished finish is locked to prevent peeling. A characteristic repair method for anticorrosion pipes. 3. The method for repairing an anticorrosion pipe according to claim 2, wherein the covering member is thicker at a central portion of the upper surface than at other portions. Construction method.