JP7612646B2 - Repair method for oil leaks in oil-filled cables - Google Patents

Description

The present invention relates to a method for repairing oil leaks in oil-filled cables.

Conventionally, in OF (Oil-Filled) cables with oil passages, insulating oil is injected and filled inside the cable at a specified pressure to ensure insulation. In OF cables, oil leakage can occur when the metal coating that maintains the hydraulic pressure is damaged due to aging or accidentally damaged during construction. In such cases, it is necessary to cut the OF cable to a specified length, including the oil-leaking area, and replace it, but because replacement requires a great deal of time and effort, it is necessary to repair the oil-leaking area (temporary oil-stopping treatment) as an initial response in order to minimize the amount of oil leakage prior to replacement (full repair).

A known technique for repairing such cables is to wrap rubber or plastic tape at high tension around the cracked portion of the outer coating of the OF cable to provide a temporary fixing layer, and then laminate a layer of glass fiber tape and an epoxy resin layer on top of that to provide an oil-stopping layer (see, for example, Patent Document 1). Another known technique is to strip away the anticorrosive layer around the oil leak, provide a base to surround the oil leak, install a copper pipe across the base, and join the copper pipe and base with leadwork (see, for example, Patent Document 2).

Japanese Utility Model Application Publication No. 02-037530 JP 2000-341820 A

However, the conventional end treatment of an oil-filled cable, which involves lead work as shown in Patent Documents 1 and 2, has the following problems.
That is, in the method described in Patent Document 1, in order to apply the tape to stop the oil leak, it is necessary to apply appropriate tension to the rubber, plastic tape, and glass fiber tape, and moreover, the two tapes must be wound one after the other while overlapping each other. Therefore, there is a problem that special skills are required for application and the work takes a lot of time.
Furthermore, in the conventional treatment method shown in Patent Document 1, the surface pressure on the oil stop tape applied to the lead work is not uniform, and therefore it is necessary to reinforce it with, for example, plated wire, but this creates the risk of the corrosion prevention structure itself becoming larger, resulting in increased costs.

In addition, in Patent Document 2, the work of joining the copper pipe and the base requires the special skills of a plumber, and the work is time-consuming and costly, and there is also the problem of the need to handle open flames at the construction site.

Furthermore, with the conventional repair method of overlapping and wrapping oil-blocking tapes, after a certain period of time the oil-blocking tape swells with oil and becomes easily damaged, and once oil leaks, it continues to leak, making it difficult to maintain over the long term, and there was room for improvement in this regard.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a method for repairing an oil leakage portion of an oil-filled cable which does not require the use of fire or special skills, reduces the effort and cost required for the work, and enables the treatment work to be completed efficiently in a short time.
Another object of the present invention is to provide a method for repairing an oil leaking portion of an oil-filled cable which can be maintained for a long period of time after the treatment work is completed.

(1) Aspect 1 of the method for repairing an oil leakage point in an oil-filled cable according to the present invention is a method for repairing an oil leakage point in a metal layer of a cable having an oil passage, the method comprising: a first agent application step of applying a first agent having hardening properties to one side of a metal plate made of the same material as the metal layer and having an area larger than the size of the oil leakage point and to at least one side of the oil leakage point; a metal coating formation step of attaching one side of the metal plate to the oil leakage point of the metal layer to harden the first agent and create liquid-tightness between the metal plate and a surface of the metal layer; a second agent application step of applying a second agent to the other side of the metal plate and the surface of the metal layer; and a coating layer formation step of covering the metal plate and the metal layer from above the second agent with a coating member to form a coating layer .

According to the method for repairing an oil leaking point on an OF cable of the present invention, the metal plate made of the same material as the metal layer is attached to an area of the metal layer of the cable larger than the oil leaking point through a first agent, and the metal plate and the metal layer are brought into close contact with each other as the first agent hardens, resulting in a structure in which oil passages are less likely to form. This allows the cable to be repaired efficiently in a short time using inexpensive materials, sealing the oil leaking point and preventing oil leakage.
In addition, according to the present invention, since the method forms an adhesive layer by hardening the first agent, the necessary equipment and materials can be minimized, and the effect time of the first agent can be set arbitrarily. Therefore, by adopting the first agent with a short hardening time, the first agent hardens before an oil passage is formed between the metal layer and the metal plate, preventing oil leakage, and allowing the work to be performed more quickly. Furthermore, since the metal plate is attached to the metal layer by hardening the first agent as described above, the method has excellent peel resistance and can be maintained longer and more stably than the conventional corrosion prevention method using only a leak stopper tape.

In addition, according to the present invention, compared to conventional repair work involving lead work using burners to melt lead, no special skills are required because lead is not used, and there is no need to secure workers with advanced construction skills, which improves work efficiency and reduces costs. Moreover, compared to lead work, terminal treatment can be performed without the need to handle open flames.

Furthermore, according to the method for repairing an oil leaking portion of an oil-filled cable of the present invention, a metal plate is attached to the oil leaking portion together with the hardened first agent, so that higher toughness can be ensured compared to the conventional treatment of wrapping multiple leak-stopping tapes around the portion. In other words, a highly tough and robust treatment structure that can withstand the internal pressure from the oil in the oil passage and the external pressure from the outside can be obtained, and can be maintained stably for a long time.
Furthermore, in the present invention, the first chemical fills the gap between the metal plate and the metal layer without leaving any gaps even if there is some oil, and hardens.

In this case, the second agent is also applied to the upper layer of the metal plate, so that the strength of the metal layer can be further increased by the hardened second agent, resulting in a structure that is more resistant to external damage. Moreover , since a covering member is provided so as to cover the metal plate via the second agent, there is an advantage that oil leakage is further prevented.

The method for repairing an oil leaking portion of an oil-filled cable according to the present invention does not require the use of fire or special skills, reduces the effort and cost required for the work, and enables the treatment work to be completed efficiently in a short time.
Furthermore, the method for repairing an oil leakage portion of an oil-filled cable according to the present invention can be maintained for a long period of time after the treatment work is completed.

1 is a side cross-sectional view showing a processing structure for an OF cable according to an embodiment of the present invention. 1A to 1C are diagrams illustrating a procedure for repairing an oil leak point in an oil-filled cable. 2A and 2B are diagrams showing the procedure following FIG. 2C.

Below, an embodiment of the method for repairing an oil leak point in an OF cable according to the present invention will be described with reference to the drawings. Note that in each drawing, the scale of each component may be appropriately changed as necessary to make each component large enough to be visible.

As shown in FIG. 1, the method for repairing an oil leak in an OFC cable according to this embodiment is a repair method for sealing an oil leak in a metal layer 11 arranged on the outer periphery of an OFC cable 1 having an oil passage with oil injected inside. That is, the method for repairing an oil leak in an OFC cable repairs the oil leak by applying a cable treatment structure 10 to the oil leak. The oil leak is a pinhole that has appeared in a lead treatment part (metal layer 11) made of a meta-lead plate at the connection of the OFC cable 1.

The method for repairing oil leaks in an oil-tight cable according to this embodiment is intended to be applied as a temporary repair carried out as an initial measure prior to a permanent repair, but depending on the oil leak condition, the number of years the oil-tight cable 1 has been in use, the installation environment, etc., the method may be applied as a permanent repair.

The cable processing structure 10 is a structure in which a metal plate 3 is attached to a metal layer 11. The cable processing structure 10 includes a first adhesive bond 2 (first agent) applied to the surface (outer surface 11a of the metal layer 11) including the oil leakage point P of the OF cable 1, a metal plate 3 attached by adhesion to the outer surface 11a of the metal layer 11 via the first adhesive bond 2, a second adhesive bond 4 (second agent) applied to the outer surface 3a (other side) of the metal plate 3 and the outer surface 11a of the metal layer 11, and a coating layer 5 formed by covering the metal plate 3 and the metal layer 11 from the upper layer side of the second adhesive bond 4 with a casting tape 51 (coating member).

The first adhesive bond 2 is applied over an area larger than the oil leak point P so as to cover the oil leak point P. In other words, the application area of the first adhesive bond 2 corresponds to the attachment area of the metal plate 3. As the first adhesive bond 2, for example, the Y618H type of Metallock (manufactured by Cemedine Co., Ltd.), which has hardening properties and is a high-strength, room-temperature fast-curing adhesive that does not require heating and is mainly composed of modified acrylic, can be used. The Y618H type adhesive bond has a higher bonding strength to metal than the Y610 type manufactured by the same company. When the Y618H type is used, it can perform the oil stop function regardless of the surface pressure of the metal plate 3. In addition, the Y618H type does not contain a flammable solvent, hardens even with a rough mixture, can harden at a temperature of 0°C, and has the property of obtaining adhesive strength even in a slightly oily surface state. In addition, it is preferable that the hardening time is fast, for example, about 2 minutes 30 seconds to 10 minutes 0 seconds. Furthermore, it can be stored for long periods at room temperature between 5 and 25°C and does not emit any foul odors like conventional acrylic adhesives. It can also be used to join dissimilar materials such as metal and CFRP.

The metal plate 3 is made of the same material as the metal layer 11, for example lead. The metal plate 3 has an area that is large compared to the size of the oil leakage location P. Therefore, the planar shape of the metal plate 3 can be set to, for example, a rectangular shape, but is not particularly limited. The thickness of the metal plate 3 is, for example, about 0.3 to 1.0 mm.

The metal plate 3 is adhered to the outer peripheral surface 11a of the metal layer 11 by the first adhesive bond 2, and when the first adhesive bond 2 hardens, a liquid-tight state is created between the metal plate 3 and the outer peripheral surface 11a of the metal layer 11.
The timing for attaching the metal plate 3 to the outer peripheral surface 11a of the metal layer 11 is preferably such that after the first adhesive bond 2 starts to harden, a predetermined time is waited, and then the metal plate 3 is adhered to the metal plate 3 when the viscosity of the first adhesive bond 2 has risen to, for example, 15,000 mPa·s at 23°C.

The second adhesive bond 4 is applied to the entire area of the outer surface 3a of the metal plate 3 and to the outer peripheral surface 11a of the metal layer 11 including the metal plate 3, up to a predetermined area around the metal plate 3. The second adhesive bond 4 has a hardening property. Specifically, the same material as the first adhesive bond 2 can be used.

The casting tape 51 is wrapped around the entire area of the applied second adhesive bond 4. As a result, the casting tape 51 forms a coating layer 5 that covers the entire area of the outer surface 3a of the metal plate 3, and the metal plate 3 on the outer peripheral surface 11a of the metal layer 11, and covers a predetermined area around the metal plate 3. The area covered by the casting tape 51 is large compared to the size of the metal plate 3. One surface (inner peripheral surface 5a) of the coating layer 5 is in a state where the second adhesive bond 4 is applied.

Next, the repair procedure of the OFC cable oil leakage point repair method applied to the oil leakage point P in the metal layer 11 of the OFC cable 1 having an oil passage will be explained in detail using Figures 2 (a) to (c) and Figures 3 (a) and (b).

As shown in FIGS. 1 and 2( a ), an oil leakage site P occurs in the metal layer 11 of the OF cable 1 .
First, a predetermined area of the metal layer 11 including the oil leakage location P is struck with a hammer to reduce the amount of oil leakage (leakage reduction step). That is, a caulking process is performed using a hammer to close holes and cracks in the oil leakage portion of the oil leakage location P.

Next, as shown in FIG. 2(b), a first adhesive bond 2 having hardening properties is applied to one side of a metal plate 3 made of the same material as the metal layer 11, which has an area larger than the size of the oil leakage location P, and to at least one side of the oil leakage location P (first chemical application process). The first adhesive bond 2 is hardenable when applied to the application surface containing oil.

2(c), the inner surface 3b of the metal plate 3 is attached to the oil leakage point P of the metal layer 11, the first adhesive bond 2 is hardened, and a metal coating is formed between the metal plate 3 and the outer peripheral surface 11a of the metal layer 11 to create liquid-tightness (metal coating formation process). In the metal coating formation process, a predetermined time is waited after the hardening of the first adhesive bond 2 starts, and the metal plate 3 is brought into close contact when the viscosity of the first adhesive bond 2 increases (oil path formation prevention process). By performing the oil path formation prevention process in this way, the hardening time of the first adhesive bond 2 after the metal plate 3 is brought into close contact can be shortened, and the formation of an oil path for oil leaking from the oil leakage point P can be prevented. That is, the first adhesive bond 2 hardens in the area where the first adhesive bond 2 is applied, and the gap between the metal plate 3 and the metal layer 11 can be sealed without gaps, and the oil in the oil path of the OF cable 1 can be prevented from leaking out from the oil leakage point P.

Next, as shown in FIG. 3(a), the second adhesive bond 4 is applied to the outer surface 3a of the metal plate 3 and the outer peripheral surface 11a of the metal layer 11 (second chemical application process). The second adhesive bond 4 can be cured even when applied to an oily application surface. The second adhesive bond 4 applied to the metal layer 11 in FIG. 3(a) covers the entire periphery of the metal plate 3.

Next, as shown in FIG. 3(b), the metal plate 3 and the metal layer 11 are covered with the casting tape 51 from the upper layer side of the second adhesive bond 4 to form the coating layer 5 (coating layer forming process). Specifically, the casting tape 51 is wrapped around the upper layer side of the second adhesive bond 4 so as to cover and encase it. The casting tape 51 is provided in a liquid-tight contact state with the second adhesive bond 4.

An anticorrosive tape (not shown), such as polyvinyl chloride (PVC), may be wrapped around the entire coating layer 5 from the upper layer side to encase it. This provides corrosion protection to the portion reinforced with the casting tape 51 due to the anticorrosive properties of the anticorrosive tape. In this way, wrapping the anticorrosive tape around the upper layer side of the casting tape 51 not only provides an anticorrosive effect, but also prevents the casting tape 51 from swelling.

Next, the operation of the oil leakage repair method for an oil-filled cable will be described in detail with reference to Figs.
The method for repairing an oil leakage point in an OFC cable according to this embodiment is applied to an oil leakage point P in a metal layer 11 of a cable having an oil passage. The method for repairing an oil leakage point in an OFC cable includes a first chemical application step of applying a first adhesive bond 2 having hardening properties to at least one side of the oil leakage point P and one side of a metal plate 3 made of the same material as the metal layer 11 having an area larger than the size of the oil leakage point P, and a metal coating formation step of attaching the one side of the metal plate 3 to the oil leakage point P of the metal layer 11, hardening the first adhesive bond 2, and creating liquid-tightness between the metal plate 3 and the surface of the metal layer 11.

According to the method for repairing an oil leak point in an OF cable according to this embodiment, the simple task of simply attaching a metal plate 3 made of the same material as the metal layer 11 via a first adhesive bond 2 to an area of the metal layer 11 of the cable that is larger than the oil leak point P allows the metal plate 3 and the metal layer 11 to adhere to each other as the first adhesive bond 2 hardens, resulting in a structure in which it is difficult for an oil passage to form. This allows the cable oil leak point P in the cable to be sealed, and cable repair processing that prevents oil leakage can be carried out efficiently in a short time using inexpensive materials.

In addition, according to this embodiment, since the method forms an adhesive layer by hardening the first adhesive bond 2, the necessary materials and equipment can be minimized, and the effective time of the first adhesive bond 2 can be set as desired. Therefore, by adopting the first adhesive bond 2 with a fast hardening time, the first adhesive bond 2 hardens before an oil passage is formed between the metal layer 11 and the metal plate 3, preventing oil leakage, and allowing the work to be performed more quickly. Furthermore, as described above, the metal plate 3 is attached to the metal layer 11 by hardening the first adhesive bond 2, which has excellent peel resistance and can be maintained for a longer period of time and more stably than the conventional corrosion prevention method using only a leak stopper tape.

In addition, in this embodiment, compared to conventional repair work involving lead work using burners to melt lead, no special techniques are required because lead is not used, and there is no need to secure workers with advanced construction techniques, which improves work efficiency and reduces costs. Moreover, compared to lead work, terminal processing can be performed without the need to handle open flames.

Furthermore, according to the OF cable oil leakage portion repair method of the present embodiment, the metal plate 3 is attached to the oil leakage portion P together with the hardened first adhesive bond 2, so that higher toughness can be ensured compared to the conventional treatment of wrapping a plurality of leak stop tapes. That is, a highly tough and robust treatment structure capable of withstanding the internal pressure from the oil in the oil passage and the external pressure from the outside can be obtained, and can be maintained stably for a long time.
Furthermore, in this embodiment, even if there is a small amount of oil, the first adhesive bond 2 fills the gap between the metal plate 3 and the metal layer 11 without leaving any gaps, and hardens.

In addition, this embodiment includes a second chemical application process in which a second adhesive bond 4 is applied to the other side of the metal plate 3 and the outer peripheral surface 11a of the metal layer 11, and a coating layer formation process in which the metal plate 3 and the metal layer 11 are covered from the upper layer side of the second adhesive bond 4 with a casting tape to form a coating layer 5.

Therefore, the second adhesive bond 4 is also applied to the upper layer side of the metal plate 3, so that the strength of the metal layer 11 can be further increased by the hardened second adhesive bond 4, resulting in a structure that is more resistant to external damage. Furthermore, the casting tape is provided so as to cover the metal plate 3 via the second adhesive bond 4, which has the advantage of making it even less likely for oil to leak.

In addition, this embodiment includes a leakage reduction step of hitting a predetermined area of the metal layer 11 including the oil leakage location P with a hammer to reduce the amount of oil leakage.
Therefore, by first caulking the oil leakage portion with a hammer to close it up, and then applying the first adhesive bond 2 and attaching the metal plate 3, a cable processing structure can be provided that can achieve the above-mentioned effect even if the amount of oil leaking from the oil leakage point P is large.

Furthermore, in this embodiment, the metal coating formation process waits for a predetermined time after the start of hardening of the first adhesive bond 2, and then adheres the metal plate 3 when the viscosity of the agent has increased, thereby shortening the hardening time of the first adhesive bond 2 after adhesion and also including an oil passage formation prevention process for preventing the formation of an oil passage for oil leaking from the oil leakage location P.
Therefore, the metal plate 3 is attached to the metal layer 11 when the viscosity of the first adhesive bond 2 increases, so that an oil passage is unlikely to be formed between the metal plate 3 and the metal layer 11 after attachment, and the adhesion of the metal plate 3 can be improved.

In addition, in this embodiment, the metal layer 11 and the metal plate 3 are made of lead, so by bringing the lead plates into close contact with each other, it is possible to perform a process that makes it more difficult for oil passages to form.

The method for repairing an oil leak point on an OF cable according to this embodiment, configured as described above, does not require the use of fire or special skills, reduces the effort and cost required for the work, and enables the treatment work to be completed efficiently in a short time.
Furthermore, the method for repairing an oil leakage portion of an oil-filled cable according to this embodiment can be maintained for a long period of time after the treatment work is completed.

Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. Examples of the embodiments and their variations include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the scope of equivalents.

For example, in the above embodiment, after the metal plate 3 is attached, the coating layer 5 is applied by wrapping the casting tape 51 around the upper layer side via the second adhesive bond 4, but it is also possible to omit the casting tape 51 and the second adhesive bond 4.

In addition, this embodiment includes a leakage reduction process in which a specific area of the metal layer 11, including the oil leakage point P, is struck with a hammer to reduce the amount of oil leakage, but the leakage reduction process can be performed as needed and can also be omitted.

1 OF cable 2 First adhesive bond (first agent)
3 Metal plate 4 Second adhesive bond (second agent)
5 Covering layer 51 Casting tape (covering member)
10 Cable processing structure 11 Metal layer 11a Outer circumferential surface P Oil leakage location

Claims (1)

An oil leakage repair method for an oil-filled cable that is applied to an oil leakage location in a metal layer of a cable having an oil passage, comprising:
A first agent application process for applying a first agent having hardening properties to at least one side of the oil leakage location and one side of a metal plate made of the same material as the metal layer and having an area larger than the size of the oil leakage location;
a metal coating forming process in which one side of the metal plate is attached to the oil leakage portion of the metal layer to harden the first agent and create liquid-tightness between the metal plate and the surface of the metal layer;
A second agent application step of applying a second agent to the other side of the metal plate and the surface of the metal layer;
A coating layer forming step of covering the metal plate and the metal layer with a coating member from the upper layer side of the second drug to form a coating layer .
Repair method for oil leaks in oil-filled cables.

Images