Of cable oil leak repair agent and oil leak repair method

Abstract

To provide an oil leak repair agent with enhanced workability for efficient oil leak repairs, and a simplified oil leak repair method using the same.SOLUTION: The present invention relates to an OF cable oil leak repair agent that is primarily composed of a polymer solution containing 10-25 pts.mass of styrenic elastomer powder and 100 pts.mass of hydrocarbon solvent, and an OF cable oil leak repair method using the OF cable oil leak repair agent. The OF cable oil leak repair method includes the steps of: placing an oil guide bag to cover the lead-sealed area of the connection part in the cable; repairing both ends of the oil guide bag; and repairing the central area of the oil guide bag. The steps of repairing both ends and the central area each include a stage for applying the oil leak repair agent.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an oil leakage repair agent for OF (insulating oil-filled) cables and an oil leakage repair method. More specifically, the present invention relates to an oil leakage repair agent and an oil leakage repair method for OF cables that can repair oil leakage in a short time by absorbing and gelling oil leaked from oil leakage points (cable parts, joint parts, flange parts at joint parts, etc.) of OF cables. [Background technology]

[0002] Metallic piping containing hydraulic oil, working oil, insulating oil, etc. may leak oil due to deterioration or shrinkage of the metal, and the leaked oil may ignite, causing fires, accidents, and environmental pollution.

[0003] Conventionally, the main method for repairing oil leaks in OF cables was re-leading (reducing the amount of oil leakage by wrapping with vulcanized rubber before repair, switching to a work oil supply system, removing the existing lead work, applying re-leading by vacuuming, and after the lead work is completed, vacuuming, vacuum drop testing, oil injection, checking for oil leakage, followed by epoxy reinforcement and the formation of a corrosion protection layer) (see Figure 6). However, there were issues with efficiency, such as the risk of fire due to the use of open flames and the need for construction by experienced technicians, so there was a demand for more efficient construction, such as construction without open flames, shortening the time the cable was down, and not requiring expertise.

[0004] Known oil leakage repair methods include a method using a synthetic rubber sheet that has elasticity and insulating oil resistance (Patent Document 1), a method applying an epoxy resin-based sealant (Patent Document 2), and a method of applying a styrene-based elastomer and an ultraviolet-curable acrylic resin composition and hardening it by irradiating it with ultraviolet light (Patent Document 3). However, these methods are difficult to handle and do not completely stop oil leakage. On the other hand, there is also an epoxy-based two-part mixed caulking material that can be used inexpensively, but it is difficult to work with and hardens in a short time, making it difficult to remove when reworking. Therefore, these conventional techniques are unable to completely stop oil leakage and have poor work efficiency.

[0005] On the other hand, Patent Document 4 discloses that a powdered oil solidifier, which is a mixture of a styrene / butadiene copolymer having polystyrene block phases at both ends of the polymer and a styrene-ethylene / butylene copolymer in a specific ratio, is effective for solidifying heavy oil and household kerosene, but the oil solidifier is designed to solidify the oil and collect it with a net.

[0006] Furthermore, Patent Document 5 discloses a clay-like oil-absorbent adhesive coating repair material made by kneading and gelling a mixture of hydrogenated polyisobutylene and polystyrene, and a polystyrene / hydrogenated polyisoprene / polybutadiene / polystyrene copolymer with a petroleum-based hydrocarbon solvent. This oil solidifier is a repair material for emergency repair of oil leaks, but because it is a clay-like repair material made by kneading and gelling with a petroleum-based hydrocarbon solvent, it is difficult to work with and has poor adhesion to the oil leaks. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2006-333674 A [Patent Document 2] JP 2012-211652 A [Patent Document 3] JP 2019-203111 A [Patent Document 4] Japanese Patent Application Publication No. 9-137185 [Patent Document 5] JP 2020-055794 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above problems, and has an object to provide an oil spill repair agent with excellent workability so as to efficiently carry out oil spill repair, and a simpler oil spill repair method using the same. [Means for solving the problem]

[0009] In response to the above-mentioned problems, the inventors of the present invention have investigated various materials for repair agents for oil leakage from OF cables that have excellent oil resistance, can withstand the hydraulic pressure of oil spurting out when oil leaks from OF cables and can stop the spurt out, have a short hardening time, are insulating and adhesive (i.e., adhesiveness to metal members), and become elastic and rubber-like after hardening. As a result, they have concluded that an improvement to a block copolymer of styrene and butadiene, which has properties close to the required performance, is optimal.

[0010] However, the above-mentioned styrene-butadiene block copolymer is a gel-like putty that is lipophilic to the oil on the bonding surface, but has a problem with sealing when oil is present on the bonding surface. In order to further improve the function, we have conducted extensive research into a material that can adsorb oil, has sealing properties even when oil is present on the bonding surface, is easy to work with, can be easily reapplied, and can maintain the oil leakage repair for a certain period of time, and as a result, we have arrived at this invention.

[0011] That is, the present invention provides a repair agent for oil leakage from an OF cable, characterized in that the main component is a polymer solution containing 10 to 25 parts by mass of a styrene-based elastomer powder and 100 parts by mass of a hydrocarbon-based solvent.

[0012] The present invention also provides a method for repairing an oil leak in an OF cable using the above-mentioned OF cable oil leak repair agent, comprising the steps of: A step of covering a lead wire portion of the connection part of the cable with an oil guide bag; A step of repairing both ends of the oil guide bag; Repairing the central portion of the oil guide bag; having A step of applying the oil leakage repair agent to each of the steps of repairing the both end portions and the central portion. The present invention provides a method for repairing oil leakage from an oil-filled cable, comprising the steps of:

[0013] According to the present invention, it is not necessary to remove the existing lead work and re-apply new lead work, which is a complicated repair work that requires skill, so compared to the conventional method (re-leading), it is possible to shorten the cable downtime, reduce skills, and reduce costs. It is safe because it does not use fire.

[0014] The oil leakage repair agent of the present invention has a high ability to adsorb oil leaked from oil leakage points such as piping, flanges, terminal connections, and intermediate connections of OF cables, has good workability, is easy to reapply, and can maintain oil leakage repair for a certain period of time. It also has the effect of suppressing oil vapor (gas generation) and suppressing ignition due to static electricity. Furthermore, since the oil leakage repair agent absorbs and solidifies the oil, it is only necessary to apply or spray the oil leakage repair agent on the oil leakage point, eliminating the need for the rubber packing replacement work that was previously necessary.

[0015] In addition, in order to prevent oil leakage from the leadwork as much as possible, before the process of covering the oil guide bag, the process of wrapping vulcanized rubber tape around the oil leakage point and wrapping self-fusing tape over the vulcanized rubber tape may be included.

[0016] In the oil leakage repair method, the oil leakage bag has an outlet, In the step of covering the oil guide bag, the outlet is positioned below the oil guide bag.

[0017] By using the oil guide bag, it is possible to guide the outflow of oil during repair work and efficiently drain the oil outside the system. Furthermore, by efficiently draining the oil outside the system, it is possible to reduce the pressure rise during construction due to oil leakage, improving workability.

[0018] Moreover, the oil leakage repair method preferably further comprises, after the step of repairing the central portion, a step of applying the oil leakage repair agent so as to cover the entire repair area.

[0019] In addition, the step of applying the oil leak repair material is preferably carried out by applying multiple coats of the material while checking the drying of each coat.

[0020] In order to thicken the cured layer after application of the oil leakage repair agent, it is preferable to apply the oil leakage repair agent multiple times. When applying the oil leakage repair agent, it is preferable to apply it via an interlayer primer, since this can improve adhesion to the OF cable and oil leakage prevention.

[0021] The step of repairing both ends further comprises: A step of overlapping and wrapping the periphery of both ends of the oil guide bag with self-fusing tape; A step of overlapping and winding a cloth tape so as to cover the self-fusing tape; applying the oil leak repair agent onto the cloth tape; applying the oil leak repair material and then applying an epoxy resin; It is preferred that the compound has the formula:

[0022] The step of repairing the central portion includes: A step of wrapping a self-adhesive tape around the central portion of the oil guide bag; A step of overlapping and winding a cloth tape so as to cover the self-fusing tape; applying the oil leak repair agent onto the cloth tape; applying the oil leak repair material and then applying an epoxy resin; It is preferred that the compound has the formula:

[0023] By wrapping the self-adhesive tape and cloth tape in that order, applying the oil leakage repair agent, drying it to form a hardened layer, and then forming an epoxy resin hardened layer on top of the hardened layer, the double hardened layer can completely prevent oil leakage. It is preferable to apply the epoxy resin reinforcement in two stages, in the longitudinal direction and then the transverse direction of the cable, which makes it possible to reinforce the leadwork while securing an outlet for oil. Effect of the Invention

[0024] According to the present invention, it is possible to provide an oil leakage repair method for OF cables that can reliably perform repairs without relying on the skill of the worker, while improving work efficiency and reducing costs, and an oil leakage repair agent that is optimal for the method. [Brief description of the drawings]

[0025] [Figure 1A] FIG. 13 is an explanatory diagram showing an example of application of an oil leakage repair agent to a terminal connection (before repair). [Figure 1B] FIG. 13 is an explanatory diagram showing an example of application of an oil leakage repair agent to a terminal connection (after repair). [Diagram 2] 1 is a flowchart showing an example of a process of an embodiment of an oil leakage repair method. [Diagram 3] FIG. [Figure 4] (a) A schematic diagram of the oil guide bag installed to cover the lead work section, (b) a schematic diagram of the state after end treatment has been performed at the open ends of the oil guide bag, and (c) a schematic diagram of the state after similar repairs have been made in the center section (lead work section). [Diagram 5] (a) A diagram of the epoxy resin being applied, (b) a diagram of the interlayer primer being applied, (c) a diagram of the epoxy resin being applied to the center section (lead work section), and (d) a diagram of the completed oil leak repair. [Figure 6] FIG. 1 is an explanatory diagram of a conventional oil leakage repair method for an intermediate joint. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Preferred embodiments of the present invention will now be described in detail.

[0027] The oil leakage repair agent for an OF cable according to the present invention is characterized in that it contains, as a main component, a polymer solution containing 10 to 25 parts by mass of a styrene-based elastomer powder and 100 parts by mass of a hydrocarbon-based solvent.

[0028] The oil leakage repair agent for the OF cable in the present invention is mainly composed of a polymer solution containing a styrene-based elastomer powder and a hydrocarbon-based solvent, and is in the form of a highly viscous solution with good fluidity. By making the oil leakage repair agent in the form of a polymer solution rather than a powder, it is easy to apply to the oil leakage location and can be prevented from flowing out after application.

[0029] The oil leakage repair agent preferably has a viscosity of 70 to 2000 mPa·s when measured with a BM type viscometer (rotor 1, rotation speed 3 rpm). If the viscosity is less than 70 mPa·s, there is a risk that the oil leakage repair agent applied with a brush will flow out from the oil leakage site, making it impossible to stop the oil leakage. If the viscosity exceeds 2000 mPa·s, it becomes difficult to apply with a brush, which significantly reduces workability and may make it difficult to apply the agent uniformly to the oil leakage site. The viscosity of the oil leakage repair agent is more preferably 90 to 1500 mPa·s, even more preferably 100 to 500 mPa·s, and particularly preferably 100 to 300 mPa·s.

[0030] <Styrene-based elastomer> The styrene elastomer powder constituting the oil leak repair agent of the present invention is prepared by powdering a styrene elastomer in a conventional manner.

[0031] In order to quickly gelatinize leaked oil, the particle size of the styrene-based elastomer powder is preferably such that, when sieved through a JIS test sieve of 16 mesh (1.00 mm opening), 90% by mass or more of the powder passes through the sieve. The amount of powder that passes through the sieve is more preferably 95% by mass or more, and even more preferably 97% by mass or more. When the proportion of powder that passes through the sieve increases, the particle size of the powder becomes smaller and the surface area increases, allowing a larger amount of oil to be absorbed. In addition, the swelling rate of the styrene-based elastomer due to oil also increases, so that oil leakage can be prevented by quickly absorbing the oil, and the working time can be shortened.

[0032] On the other hand, if the particle size of the styrene-based elastomer powder is too fine, the polymer solution becomes highly viscous, making it difficult to apply the solution uniformly to the repaired area, which may result in a decrease in the efficiency of the repair work. Therefore, it is particularly preferable that 90% or more of the styrene-based elastomer powder has a particle size in the range of 125 μm (passing a 119 mesh sieve) to 1.00 mm. By making the particle size of the styrene-based elastomer powder uniform in this way, it is possible to suppress the phenomenon in which the insulating oil melts before the oil leakage repair material completely solidifies, and a uniform cured resin layer is formed, making it easy to remove the repaired area when re-applying the material.

[0033] As the styrene-based elastomer, from the viewpoints of heat resistance and flexibility, a block copolymer is preferred, and among them, a block copolymer consisting of at least one polymer block containing a styrene unit and at least one polymer block containing a conjugated diene or a diene compound unit similar thereto is preferred.

[0034] Specific examples of preferred styrene-based elastomers include styrene-butadiene-styrene block copolymers, styrene-isoprene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, styrene-ethylene-butadiene-styrene block copolymers, and hydrogenated products thereof. These block copolymers may be used alone or in combination of two or more. Among the block copolymers, hydrogenated products of styrene and conjugated dienes are particularly preferred. Hydrogenated products have good heat resistance and light resistance because they do not have unsaturated bonds.

[0035] The block copolymer has polystyrene block phases at both ends of the polymer structure, and the molecular structure is preferably a linear block copolymer, mainly composed of styrene-butadiene-styrene block copolymer. Having both ends of the molecular structure as polystyrene block phases, it is highly effective in gelling oil and preventing oil leakage. If all or part of the ends of the molecular structure are polybutadiene block phases or polyisoprene block phases, the gel that absorbs the leaked oil becomes weak, making it difficult to completely stop the oil leakage.

[0036] In the above block copolymer, the content of the polystyrene block is not particularly limited, but is preferably 10 to 50% by mass, more preferably 20 to 45% by mass. Particularly preferably 25 to 40% by mass. The content of the polybutadiene block or polyisoprene block is preferably 50 to 90% by mass, more preferably 55 to 80% by mass. Particularly preferably 60 to 75% by mass. If the ratio of the polystyrene block is less than 10% by mass, the oil-absorbed gel becomes weak, and if it exceeds 50% by mass, the gel becomes too hard, resulting in poor workability. The hydrogenation ratio of the polybutadiene block and the polyisoprene block is not particularly limited, but is preferably 50 mol% or more, more preferably 70 to 100 mol%.

[0037] The hydrogenated product of the styrene-butadiene-styrene block copolymer is a styrene-ethylene-butylene-styrene block copolymer, and the hydrogenated product of the styrene-isoprene-styrene block copolymer is a styrene-ethylene-propylene-styrene block copolymer.

[0038] The styrene-based elastomer of the present invention preferably has a weight average molecular weight of 300,000 or more, more preferably 1,000,000 or more. There is no particular upper limit, but it is, for example, 1,500,000 or less. By including such a high molecular weight styrene-based elastomer, there is no deterioration over time (coloration) compared to the case where a low molecular weight styrene-based elastomer is used, and the sealing property of the oil leaking part can be maintained for a long time after the oil leak is repaired.

[0039] In this specification, the weight average molecular weight of the styrene-based elastomer is a value calculated in terms of polystyrene (standard material) measured by gel permeation chromatography (GPC) (standard material: polystyrene, eluent: tetrahydrofuran).

[0040] In the present invention, commercially available products can be used as the styrene-based elastomer. Examples of commercially available products include "Kraton (registered trademark) G" manufactured by Kraton Polymers, Inc., "Septon (registered trademark)" manufactured by Kuraray Co., Ltd., and "Tuftec (registered trademark)" manufactured by Asahi Kasei Corporation.

[0041] <Hydrocarbon solvents> The content of the styrene-based elastomer powder in the oil leak repair agent of the present invention is 10 to 25 parts by mass relative to 100 parts by mass of the hydrocarbon solvent. The content of the styrene-based elastomer powder is preferably 10 to 23 parts by mass, more preferably 12 to 23 parts by mass, and particularly preferably 15 to 20 parts by mass.

[0042] If the ratio of styrene-based elastomer powder to 100 parts by mass of hydrocarbon solvent is low, the oil leak repair agent becomes too soft, which may cause problems such as dripping when applied to the oil leak area. If the styrene-based elastomer powder is 10 parts by mass or more, the oil absorption ability of the powder does not decrease excessively, and the oil is absorbed and a stable gel is formed, allowing the oil leak repair performance to be demonstrated. Also, if the styrene-based elastomer powder is 25 parts by mass or less, the polymer solution does not become extremely viscous, so workability is not significantly impaired.

[0043] In the present invention, a styrene-based elastomer powder can be obtained by crushing a styrene-based elastomer with a crusher, sieving the crushed product, adding additives as desired to the sieved fraction, and uniformly mixing them with a mixer. The styrene-based elastomer powder can then be mixed with additives such as silica powder and olefin wax, and dissolved in a hydrocarbon solvent to prepare a polymer solution.

[0044] On the other hand, the styrene-based elastomer powder blended in the oil leakage prevention agent of the present invention can be used as an oil leakage repair agent by directly scattering the powder on the oil leakage location when the amount of leaked oil is large. The amount of styrene-based elastomer powder required for gelling insulating oil is usually smaller when the insulating oil for OF cable has a low viscosity, and is larger as the viscosity increases. At room temperature, the leaked oil can be gelled by applying an appropriate amount of styrene-based elastomer powder to a general insulating oil. The amount of styrene-based elastomer powder applied per part by mass of insulating oil is not particularly limited, and is preferably about 1 to 20 parts by mass. The styrene-based elastomer powder may be blended with additives such as silica powder and olefin wax.

[0045] In the oil leak repair agent of the present invention, a hydrocarbon solvent is used to turn the styrene elastomer powder into a high-viscosity polymer solution. The polymer solution absorbs the oil when applied to the oil leak location. The polymer that has absorbed the oil then hardens (solidifies) over time (usually about 24 to 48 hours).

[0046] The hydrocarbon solvent preferably has a boiling point (760 mmHg) of 78°C to 110°C. If the boiling point is 78°C or higher, the volatilization of the solvent during oil leakage repair work can be suppressed, which is preferable in terms of the working environment, and the hardening rate of the oil leaked from the OF cable can be prevented from decreasing. Also, if the boiling point is 110°C or lower, the solidification rate of the polymer is not significantly delayed.

[0047] Specific examples of hydrocarbon solvents include aliphatic hydrocarbons such as heptane and isooctane, aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene, alicyclic hydrocarbons such as methylcyclopentane, cyclohexane, methylcyclohexane, and cyclohexene, mineral oils (paraffinic and naphthenic), alkylbenzene, polybutene, alkylnaphthalene, and non-aromatic hydrocarbons. From the viewpoint of ensuring the safety of work, it is desirable that the hydrocarbon solvent has a high dielectric strength, a low viscosity, a high flash point, and high electrical and chemical stability. These solvents can be used alone or in combination of two or more.

[0048] Among the above-mentioned hydrocarbon solvents, mineral oil, alkylbenzene, polybutene, alkylnaphthalene, dearomatic hydrocarbons, etc. are preferred from the viewpoints of availability and economy.

[0049] <Additives> The oil leakage repair agent of the present invention may further contain silica, olefin wax, etc. By incorporating silica, it is possible to improve the blocking prevention property and long-term storage stability of the oil leakage repair agent. There is no particular limitation on the silica, and known hydrophilic silica or hydrophobic silica may be used alone or in combination of two or more kinds. By incorporating olefin wax, it is possible to improve the lipophilicity of the oil leakage repair agent.

[0050] The silica preferably has an average primary particle size of 150 μm (100 mesh) or less.

[0051] The amount of silica to be blended is preferably 1 to 10 parts by mass per 100 parts by mass of the styrene-based elastomer. By blending 1 part by mass or more, a thickening effect is exhibited, and if the amount is 10 parts by mass or less, the long-term storage stability of the oil leakage prevention agent is not significantly impaired. A more preferred blending amount is 2 to 8 parts by mass, and even more preferably 3 to 7 parts by mass. By adjusting the blending amount of silica, it is possible to adjust the hardness of the cured product formed when the oil leakage repair agent is applied to the oil leakage site.

[0052] The oil leak repair agent of the present invention can contain other known additives in known amounts other than silica and olefin wax, as long as they do not significantly impair the effects of the present invention. Examples of such additives include antioxidants, ultraviolet inhibitors, and preservatives.

[0053] In the present invention, when a powdered styrene-based elastomer, a hydrocarbon-based solvent, and other components (e.g., silica, etc.) are used in combination, for example, a mixture of the powdered styrene-based elastomer and other components is mixed with a hydrocarbon-based solvent at a temperature below the gel point of the elastomer, and the resulting mixture is heated and stirred (or kneaded) at a temperature above the gel point (30°C to 150°C) to generate a sol, and then cooled to a temperature below the gel point of the sol-forming substance to obtain an oil leak repair agent.

[0054] <Oil leak repair method> Next, an oil field cable oil leakage repair method will be described as one application example of the oil leakage repair material of the present invention. An oil field (OF) cable is a cable filled with insulating oil as an insulating material. Oil leakage can occur from the cable over time, but oil leakage troubles are particularly common at the joints (intermediate joints, terminal joints) where on-site work is carried out by installers.

[0055] In the oil leakage repair method of the present invention, first, the oil leakage location and its surroundings are cleaned. In other words, it is preferable to remove any deposits from the oil leakage location and its surroundings.

[0056] <Terminal connection part> The oil leakage repair method at the terminal connection will be explained. Figure 1A shows an example of an external photograph of an OF cable terminal connection. Oil leakage at the terminal connection often occurs from the area around the packing of the flange. Therefore, in the oil leakage repair method at the terminal connection, it is desirable to apply the oil leakage repair agent of the present invention to the oil leakage point and the entire surrounding flange, as shown in Figure 1B. When applying the oil leakage repair agent, the metal surface may be treated with a primer in advance to improve the adhesion of the styrene-based elastomer and the oil leakage repair agent to the metal surface.

[0057] After application, the coating is allowed to dry naturally or is heated to volatilize the hydrocarbon solvent, forming a coating layer of the styrene-based elastomer of the present invention on the metal surface of the oil-leaking area and the entire flange area surrounding the oil-leaking area, thereby making it possible to temporarily or short-term prevent oil leakage.

[0058] <Intermediate connection or cable section> Next, an oil leakage repair method in an intermediate joint or cable section will be described. In an intermediate joint or cable section, oil leakage often occurs around the leadwork of the intermediate joint, which is the work site of the worker. Therefore, as an example, an oil leakage repair method around the leadwork of the intermediate joint will be described. Figure 2 is a flow chart showing an example of a series of steps in the oil leakage repair method.

[0059] In this embodiment, as described above, the oil leak location and the surrounding area are first cleaned. After cleaning, it is preferable to wrap the oil leak location and the surrounding area with vulcanized rubber tape at an appropriate tension and press the area around the oil leak location with the tension of the vulcanized rubber tape. Furthermore, tape wrapping with a self-adhesive tape may be performed.

[0060] Next, in order to prevent the oil from spreading from the leaking area to other areas and affecting work, an oil guide bag (a transparent or translucent plastic bag that is easy to see from the outside) is placed around the leadwork area to cover it.

[0061] FIG. 3 is a schematic diagram of the oil guide bag used in the present invention. The upper part of the oil guide bag 30 is open, and the lower part is provided with a heat-sealed portion 33 and an oil outlet 34. One of the left and right ends of the oil guide bag is arranged on the cable side with the leadwork portion as the center. Therefore, the inner diameter 31 of one of the left and right ends of the oil guide bag is designed based on the outer diameter of the cable. On the other hand, the opposite left and right end of the oil guide bag is arranged on the intermediate joint side with the leadwork portion as the center. Therefore, the inner diameter 32 of the other end of the oil guide bag is designed based on the outer diameter of the intermediate joint end 14.

[0062] Fig. 4(a) is a schematic diagram of an oil guide bag 30 attached to cover a leadwork section 31. The oil guide bag is attached from the underside of the leadwork section so that the outlet is located on the underside of the oil guide bag. At the lower end of the oil guide bag 30, the heat-sealed section is closed, so that only the outlet 34 is open. By providing an outlet on the lower side, the oil can be effectively discharged outside the system through the outlet by its own weight.

[0063] Next, end treatment is performed on both open ends of the oil guide bag 30 so that oil inside the oil guide bag does not leak from both ends. FIG. 4(b) is a schematic diagram of the state in which end treatment has been performed on both open ends of the oil guide bag. As an example of end treatment, it is preferable to wrap both ends of the oil guide bag with self-adhesive tape and then wrap the tape with a transparent film such as vinyl. Furthermore, cloth tape may be wrapped on top of the wrap. Furthermore, it is preferable to apply an interlayer primer 41 on and around the cloth tape, and after application, it is thoroughly dried with a dryer or the like. Examples of the interlayer primer 41 include solvent-based polyurethane resin and solvent-based epoxy resin.

[0064] Next, the oil leakage repair agent of the present invention is applied onto the interlayer primer, and the oil leakage repair agent 42 is dried to form a hardened layer. It is preferable to apply the oil leakage repair material multiple times (e.g., about 20 times) while checking the drying of each application.

[0065] Furthermore, epoxy resin 43 is applied to the entire surface of the oil leakage repair agent (hardened layer), and a hardened layer of epoxy resin (for example, 5 mm or more thick) is formed over time (about 30 to 40 minutes). If necessary, it may be heated with a dryer or the like. The epoxy resin is not particularly limited, and it is preferable that it contains a hardener, a hardening accelerator, chopped glass fiber, etc. in addition to the main agent. Figure 5(a) is a diagram showing the state in which the epoxy resin is being applied.

[0066] After the end processing of both open ends of the oil guide bag 30, oil leakage repair is carried out around the center part (lead work part). Figure 4 (c) is a schematic diagram of the state where the repair has been carried out in the same manner around the center part (lead work part).

[0067] To treat the outlet of the oil guide bag 30, the outlet 34 is woven and wrapped around to cover the center (plumbing part). Then, wrap the oil guide bag multiple times to prevent oil from leaking out of the outlet 34. Furthermore, it is preferable to wrap cloth tape multiple times to hold down the wrap.

[0068] Next, an interlayer primer is applied onto the cloth tape and then thoroughly dried. Fig. 5(b) is a diagram showing the state in which the interlayer primer 41 is being applied. The oil leak repair agent of the present invention is applied to the area where the interlayer primer has been applied, and then dried and cured. It is preferable to apply the oil leak repair agent multiple times, checking the drying of each application.

[0069] Next, epoxy resin is applied onto the oil leakage repair agent (hardened layer) to form a hardened layer of epoxy resin (for example, 5 mm or more thick). Figure 5(c) shows the state in which epoxy resin 43 is applied to the center part (lead part).

[0070] Finally, the oil leakage repair agent 42 is applied to the entire surface so as to cover the entire epoxy resin cured layer formed in the previous steps. It is preferable to apply the oil leakage repair agent multiple times, checking that each application is dry. Figure 5(d) shows the state after the oil leakage repair is completed.

[0071] According to the method for repairing oil leakage from an OF cable of the present invention, the series of steps described above can reliably seal the oil leakage point, and a structure for sealing the oil leakage point can be obtained simply. In addition, the oil guide bag can guide the outflow of oil during repair work. This allows the oil to be effectively discharged outside the system, and prevents the leaked oil from delaying the drying (hardening) of the oil leakage repair agent, etc. Furthermore, by effectively discharging the oil outside the system, the pressure increase during construction due to the oil leakage can be reduced, and workability is improved. In other words, the difficulty of construction can be reduced, and the hardening time of each material can be easily secured, which can improve the quality of construction.

[0072] It should be noted that the above-described embodiment shows one embodiment of the present invention, and the present invention is not limited to these embodiments. EXAMPLES

[0073] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples.

[0074] [Example 1] Oil leak repair agents A to C (see Table 1) were prepared by mixing 75g, 90g, and 100g of three types of block copolymer powder shown in the table below, each having a weight average molecular weight of 1 million or more (all of which had a 16 mesh sieve passing rate of 97% or more, manufactured by Alpha Japan Co., Ltd.), and 500g each of dearomatized hydrocarbons (EXXSOL DSP80 / 100, manufactured by Ando Parachemie Co., Ltd.) and stirring at room temperature for 20 minutes.

[0075] [Table 1]

[0076] (1) Viscosity measurement, brushability test The viscosity of the prepared polymer solution was measured. The measurement was performed using a BM type viscometer with a rotor of 1 and a rotation speed of 3 rpm (measurement temperature: 23°C). The viscosity was also measured 1 day and 2 days after preparation. In order to make the polymer solution homogenous, the solution was stirred for 20 to 45 minutes before viscosity measurement. The measurement results are shown in Table 2.

[0077] To evaluate the brushability, the viscosity of each polymer solution was measured at low temperature two days after preparation. The measurement results are shown in Table 2. The brushability was evaluated according to the following criteria. Easy to apply: ◎, Can be applied: ○, Difficult to apply: ×

[0078] [Table 2]

[0079] From Table 1, it was found that the viscosity of the polymer solution tended to increase over time. In particular, block copolymers A and B showed a large increase in viscosity over time, and the lower the temperature, the higher the viscosity. When the viscosity of the polymer solution exceeded 150 mPa s, the brushability tended to gradually decrease, and when the temperature was below 10°C, the increase in viscosity of the polymer solution was remarkable.

[0080] (2) Shear tensile test 75g, 90g, and 100g of powder of block copolymer A, B, and C were mixed with 500g of dearomatized hydrocarbon (EXXSOL DSP80 / 100), respectively, and stirred at room temperature for 20 minutes to prepare oil leakage repair agents. The oil leakage repair agents A to C obtained were then applied to the adherend (aluminum plate of 24.8 x 100 x 1.5t (mm): A1050, adhesive surface polished with #600), and after bonding, a load of 370g was applied and stored in a thermostatic chamber at 33°C for 22 hours to prepare test specimens. The shear tensile test was performed using an autograph AG-X plus manufactured by Shimadzu Corporation at a tensile speed of 50mm / min. The shear tensile test was carried out three times and the average value was calculated. The results are shown in Table 3.

[0081] [Table 3]

[0082] (3) Oil resistance test An oil resistance test was conducted by immersing the solidified oil repair agent obtained by leaving oil repair agents A to C at room temperature in approximately 1000 mL of insulating oil for 48 hours. As a result, it was confirmed that there was no change in the external appearance of the oil repair agent (no dissolution).

[0083] (4) Pressure test After filling a plastic bottle with the insulating oil with a hole of about 5 mm in diameter, the hole was sealed with a polymer solution and a 0.8 MPa pressure test was conducted for 48 hours to confirm that there was no insulating oil leakage. In addition, a glass fiber tape (lattice pattern) was placed on the hole of about 5 mm in diameter, and an oil leakage repair agent was placed on top of that to seal the hole, and a 0.9 MPa pressure test was conducted for 48 hours. In both cases, it was confirmed that there was no air leakage.

[0084] (5)Curing time A polymer solution in which powder of block copolymer A was dissolved in dearomatized hydrocarbon was applied to a stainless steel tray to a thickness of 0.5 mm, and the condition was observed over time. The polymer solution hardened over time, and after 5 minutes, the hardness was such that a dent made by pressing the surface of the cured product with a finger for about 10 seconds returned to its original state when the finger was removed. The time (5 minutes) until the hardness reached that level was recorded as the curing time.

[0085] [Example 2] Elasticity tests and adhesion tests were carried out using two types of material: the block copolymer A used in Example 1 (unground product) and a mixture of block copolymer A (powder) and dearomatic hydrocarbon. (1) The elasticity test was performed by pressing the tip of a screwdriver into the test specimen (lump) with the hand of an adult male and observing whether the specimen returned to its original shape. (2) The adhesive test was performed using a 20 mm diameter (314 mm area) 2 Two iron jigs of the same size were bonded together using the block copolymer alone, and then heat-treated at 70°C for 24 hours. The bonded jigs were then subjected to measurement of adhesive strength using a tensile tester.

[0086] As shown in Table 4, the mixture of block copolymer A and a hydrocarbon solvent had better adhesion than block copolymer A alone.

[0087] [Table 4]

[0088] [Example 3] A resistance test was carried out using an oil leak repair agent (the present invention) prepared by kneading 100 g of the block copolymer A simple substance (powder) used in Example 2 with dearomatic hydrocarbons in an amount five times the mass of the powder. The device used was a resistance meter 3541 manufactured by HIOKI EE Corporation. Two types of test samples were used: one immediately after the gel was made and one several days after the gel was made (room temperature, 30 days). The test results are shown in Table 5. In all cases, the maximum range (110 MΩ) of the device used in this experiment was shown, and it was confirmed that all test items were 110 MΩ or higher.

[0089] [Table 5]

[0090] [Example 4] A polyvinyl chloride pipe with a diameter of 100 mm was used as an OF cable simulant, and a polymer solution (oil leak repair agent) consisting of block copolymer A (powder) and dearomatic hydrocarbons prepared in Example 2 was applied to the joint of two of the polyvinyl chloride pipes, and when left at 20°C for two days, the hardness became the same as that of a commercially available eraser. After that, with one opening closed, air was pumped into the pipe from the other opening at a pressure of 0.9 MPa, but no air leakage was confirmed.

[0091] [Comparative Example 1] The conventional oil leakage repair method for the intermediate joint of the oil-filled cable is shown (see Figure 6).

[0092] Conventional methods require the use of fire to remove existing lead work, which makes the work complicated, including the preparation of materials and equipment. In addition, the working environment in manholes and tunnels is not necessarily good, and there is a need to consider oxygen deficiency, so the use of fire raises concerns about the safety of the workers. In addition, after removing the existing lead work, new lead work must be applied, which requires a high level of skill on the part of the workers.

[0093] As described above, the method using the oil leakage repair agent of the present invention can be easily carried out without using special tools such as fire. Therefore, compared with conventional methods, it is less skilled, less costly, does not require the interruption of power transmission to the cable, and is also improved in terms of safety. [Industrial Applicability]

[0094] The oil leakage repair agent and oil leakage repair method of the present invention can be applied simply and easily to connections between pipes through which oil flows, and to connections such as flanges of substation equipment, hydraulic equipment, and general equipment that are at risk of oil leakage from oil-filled equipment, without the need for pre-construction processing such as removing the oil surface or scraping. In particular, in equipment where it is difficult to stop the equipment to drain the oil from the oil leakage point, repairs can be easily performed without stopping the equipment, and it is highly effective as there is no need to coordinate with the various parties involved in stopping the equipment. [Explanation of symbols]

[0095] 1 OF cable termination 2. Oil leak location 3 Oil leak repair agent 11 OF cable 12 Oil leak location 13 Plumbology Department 14 End of intermediate joint 15 Cable 30 Oil Bag 31 Cable side 32 End side of intermediate connection part 33 Heat-sealing section 34 Oil outlet 41 Interlayer Primer 42 Oil spill repair agent 43 Epoxy Resin

Claims

1. An oil leakage repair agent for oil-filled cables, characterized in that the main component is a polymer solution containing 10 to 25 parts by mass of a styrene-based elastomer powder and 100 parts by mass of a hydrocarbon-based solvent.

2. 2. The oil leak repair agent according to claim 1, wherein 90% by mass or more of the powder of the styrene-based elastomer has a particle size that passes through a 16 mesh sieve.

3. 2. The oil leak repair agent according to claim 1, wherein the styrene-based elastomer is at least one selected from the group consisting of a styrene-butadiene block copolymer, a styrene-isoprene block copolymer, and a styrene-isoprene-butadiene block copolymer.

4. 2. The oil leak repair agent according to claim 1, wherein the styrene elastomer comprises a hydrogenated styrene-butadiene-styrene block copolymer as a main component.

5. 2. The oil leak repair agent according to claim 1, wherein the hydrocarbon solvent has a boiling point (760 mmHg) of 78° C. to 110° C.

6. 6. The oil leak repair agent according to claim 5, wherein the hydrocarbon solvent is at least one selected from aliphatic hydrocarbons.

7. 2. The oil leak repair agent according to claim 1, further comprising 1 to 8 parts by mass of silica mixed therein.

8. A method for repairing oil leakage in an OF cable using the oil leakage repair agent according to any one of claims 1 to 7, A step of covering a lead wire portion of the connection part of the cable with an oil guide bag; A step of repairing both ends of the oil guide bag; Repairing the central portion of the oil guide bag; having A step of applying the oil leakage repair agent to each of the steps of repairing the both end portions and the central portion.

1. A method for repairing oil leakage from an oil-filled cable, comprising:

9. The oil guide bag has an outlet port, The oil leakage repair method according to claim 8, wherein in the step of covering the oil guide bag, the outlet is positioned below the oil guide bag.

10. 9. The oil leakage repair method according to claim 8, further comprising the step of applying the oil leakage repair agent so as to cover the entire repair area after the step of repairing the central portion.

11. The oil leakage repair method according to claim 10, wherein the step of applying the oil leakage repair agent comprises applying multiple coats of the agent while checking for drying after each application.

12. The step of repairing both ends includes: A step of overlapping and wrapping the periphery of both ends of the oil guide bag with self-fusing tape; A step of overlapping and winding a cloth tape so as to cover the self-fusing tape; applying the oil leak repair agent onto the cloth tape; applying the oil leak repair agent and then applying an epoxy resin; The oil leakage repair method according to claim 8, comprising the steps of:

13. The step of repairing the central portion includes: A step of wrapping a self-adhesive tape around the central portion of the oil guide bag; A step of overlapping and winding a cloth tape so as to cover the self-fusing tape; applying the oil leak repair agent onto the cloth tape; applying the oil leak repair agent and then applying an epoxy resin; The oil leakage repair method according to claim 8, comprising the steps of:

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