Water-resistant and fire-resistant cable and manufacturing method therefor and application thereof

Abstract

Provided in the present invention are a water-resistant and fire-resistant cable and a manufacturing method therefor and application thereof. The water-resistant and fire-resistant cable comprises an electric unit conductor, a fire-resistant layer, an insulating layer, a thermal insulation layer, a shielding layer and a sheath layer, wherein the fire-resistant layer covers the surface of the electric unit conductor, the insulating layer covers the surface of the fire-resistant layer, the thermal insulation layer covers the surface of the insulating layer, the shielding layer covers the surface of the thermal insulation layer, the sheath layer covers the surface of the shielding layer, and the fire-resistant layer is formed by pasting basalt fibers and a reinforcing material on a surface of a fire-resistant belt. Further provided in the present invention are a method for manufacturing the water-resistant and fire-resistant cable, and an application of the water-resistant and fire-resistant cable to underwater equipment. The water-resistant and fire-resistant cable provided in the present invention has relatively high water resistance and fire resistance, and can improve the reliability of long-term operation of underwater equipment and the security and usability thereof in a faulty state.

Description

Water and fire resistant cable and its manufacturing method and application Technical Field

[0001] The present invention relates to the technical field of cables for underwater equipment, and in particular to a water- and fire-resistant cable and a manufacturing method and application thereof. Background Art

[0002] In recent years, the demand for various types of underwater equipment has been continuously expanding, and the functions of underwater equipment have become more and more powerful. At the same time, the performance requirements for underwater equipment cables supporting underwater equipment have also become higher and higher. Underwater equipment cables are used to achieve reliable connections between internal and external instruments, meters and equipment of underwater equipment to ensure safe operation. According to the application environment of underwater equipment cables, the cables must have full-section water-blocking function and be able to maintain long-term stable operation in underwater environments. Full-section water-blocking includes transverse water-blocking and longitudinal water-blocking. Transverse water-blocking refers to the ability of the cable to withstand the transverse (radial) flow of high-pressure water along the cable, and longitudinal water-blocking refers to the ability of the cable to withstand the longitudinal (axial) flow of high-pressure water along the cable. Underwater environment resistance refers to the electrical performance of the cable in a humid environment and the anti-aging performance of the cable in a salt spray environment.

[0003] With the development of intelligence, the intelligent and digital functions of underwater equipment are increasing, and the demand for power supply and control signals is also increasing. Therefore, according to actual use needs, underwater equipment cables need to develop towards lightweight, reduce the weight of underwater equipment, and increase the detection depth; improve water resistance, further improve the reliability of long-term use in seawater immersion environment, and ensure the safety of long-term continuous power supply; add fire resistance function to ensure the integrity of electrical circuits in the event of local faults and fires inside the equipment, and extend the equipment rescue time. At the same time, the fire-resistant layer has a certain toughness and can play an emergency insulation role. It can further avoid the short circuit of the burned cable conductors due to underwater tidal vibrations or foreign object impact during equipment recovery, causing secondary failure of the equipment and loss of other key components of the equipment.

[0004] Summary of the Invention

[0005] To address the above-mentioned issues, the present invention provides a water- and fire-resistant cable, a manufacturing method thereof, and its application. The water- and fire-resistant cable has high water and fire resistance, and when used in underwater equipment, can improve the long-term operational reliability, safety, and availability of the equipment in the event of a fault.

[0006] In order to achieve the above object, the present invention provides a water- and fire-resistant cable, which comprises: an electrical unit conductor, a fire-resistant layer, an insulating layer, a heat-insulating layer, a shielding layer, and a sheath layer;

[0007] The fire-resistant layer is coated on the surface of the electrical unit conductor, the insulating layer is coated on the surface of the fire-resistant layer, the thermal insulation layer is coated on the surface of the insulating layer, the shielding layer is coated on the surface of the thermal insulation layer, and the sheath layer is coated on the surface of the shielding layer;

[0008] The refractory layer is formed by overlapping and wrapping a refractory tape on the surface of the insulation layer. The refractory tape is formed by pasting basalt fiber and reinforcing material on the surface of the refractory tape.

[0009] In the water- and fire-resistant cable, the outer diameter of the basalt fiber monofilament is 9 μm-16 μm, for example, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, and other specific values, as well as ranges with any two of the above specific values ​​as endpoints.

[0010] In the above-mentioned water and fire resistant cable, the reinforcing material includes mica and / or glass fiber tape.

[0011] In some embodiments, the refractory tape can be a mica tape.

[0012] In the above-mentioned water- and fire-resistant cable, the coverage rate of the basalt fiber and the reinforcing material on the surface of the fire-resistant belt is 80%-95%.

[0013] In some specific embodiments, the refractory layer can be formed by attaching basalt fibers and reinforcing materials to a refractory tape with an adhesive, drying the tape to form a tape, and then wrapping the tape around the surface of the electrical unit conductor to cover the electrical unit conductor.

[0014] In some specific embodiments, the volume ratio of basalt fiber to reinforcing material in the refractory layer may be greater than 1:1.

[0015] In the above-mentioned water- and fire-resistant cable, the electrical unit conductors are formed by twisting conductive monofilaments. Specifically, the electrical unit conductors can be formed by twisting once or by twisting twice or more. When the electrical unit conductors are twisted twice or more, the conductive monofilaments can be first twisted to form conductive strands, which are then re-twisted to form the electrical unit conductors.

[0016] In the aforementioned water- and fire-resistant cable, each conductive monofilament can have a diameter of 0.18 mm to 0.5 mm, and an elongation at break of 30% or greater. By twisting together these highly elongated monofilaments to form the electrical unit conductors, the flexibility and bending properties of the electrical unit conductors can be improved, thereby enhancing the cable's reliability under long-term torsion and vibration conditions in underwater environments.

[0017] In the above-mentioned water and fire resistant cable, the electrical unit conductors and / or conductive strands may include bare copper strands and / or metal alloy-plated strands.

[0018] In the above-mentioned water- and fire-resistant cable, the cross-sectional area of ​​the electrical unit conductor can be 0.5mm 2 -400mm 2 The cross-sectional area of ​​the conductive strands can be 0.5-16 mm 2 .

[0019] In the above-mentioned water- and fire-resistant cable, the material of the insulation layer may include cross-linked polyethylene.

[0020] In the above-mentioned water- and fire-resistant cable, the thermal insulation layer is made of alumina fiber. For example, the thermal insulation layer may be made of alumina fiber filament fabric. The alumina fiber filament fabric may be the oxide filament fabric described in "Development of Alumina Filament Fabric" (Cotton Textile Technology, 2022, 50(S01):53-56). The manufacturing method of the alumina fiber filament fabric can refer to the manufacturing method of alumina filament fabric described in the above-mentioned document. The full text of the above-mentioned scientific document is incorporated herein by reference.

[0021] In some specific embodiments, the thermal insulation layer can be formed by wrapping alumina fiber (preferably alumina fiber filament fabric) around the outer surface of the insulation layer.

[0022] In the above-mentioned water and fire resistant cable, the shielding layer may be formed by braiding shielding monofilaments.

[0023] In the above shielding layer, the outer diameter of the shielding monofilament may be less than or equal to 0.11 mm.

[0024] In the above-mentioned shielding layer, the shielding monofilaments include nickel-plated carbon fiber or equivalent fibers (equivalent fibers mean that the shielding and mechanical properties are equivalent to those of the nickel-plated carbon fiber, and the density is light, thus achieving a weight-reducing effect). The nickel-plated carbon fiber used in the present invention has a metal strength equivalent to that of conventional tin-plated copper wire, but under the condition of the same shielding resistance, the weight of the nickel-plated carbon fiber is only less than 80% of the metal weight of the tin-plated copper wire. The use of nickel-plated carbon fiber to weave a shielding layer can significantly reduce the weight of the shielding layer.

[0025] In the aforementioned shielding layer, the shielding layer is formed by a unidirectional, flexible, and open winding method. This refers to the method of winding copper wire in a single direction, without generating stress concentration during the winding process. Compared to conventional bidirectional mesh weaving, this unidirectional, flexible, and open winding method can avoid the problem of stress concentration points on the inner surface of the sheath layer after the cable is bent, making the water- and fire-resistant cable suitable for water environments with frequent tides.

[0026] In some specific embodiments, the sum of the intervals of the unidirectional compliant winding is less than or equal to the outer diameter of the shielding monofilament.

[0027] In the aforementioned water- and fire-resistant cable, the sheath layer may be made of polyurethane. Polyurethane exhibits excellent mechanical properties, resistance to environmental corrosion, and resistance to UV radiation. Compared to sheaths made of chloroprene rubber, sheaths made of polyurethane exhibit greater abrasion resistance, effectively preventing breakage during use.

[0028] In some specific embodiments, the sheath layer made of polyurethane can withstand seawater corrosion at 70°C for 960 hours, salt spray corrosion at 35°C for 384 hours, and ultraviolet radiation for 1440 hours, significantly improving the cable's resistance to environmental corrosion and ensuring the cable's long-term application reliability.

[0029] In some specific embodiments, the tensile strength of the jacket layer is greater than or equal to 16 MPa, and the elongation at break of the jacket layer is greater than or equal to 250%.

[0030] The present invention also provides a method for manufacturing the water- and fire-resistant cable, the method comprising:

[0031] S1, sequentially performing a wire drawing process, an annealing process, and a conductor twisting process to form an electrical unit conductor;

[0032] S2, performing a first wrapping process to form a fire-resistant layer on the outer surface of the electrical unit conductor;

[0033] S3, performing a first extrusion process to form an insulating layer on the outer surface of the fire-resistant layer;

[0034] S4, performing a second wrapping process to wrap the outer surface of the insulation layer to form a heat insulation layer;

[0035] S5. Perform sparse winding treatment to form a shielding layer on the surface of the thermal insulation layer:

[0036] S6. Perform a second extrusion process to form a sheath layer on the surface of the shielding layer to obtain a water- and fire-resistant cable.

[0037] In the above manufacturing method, the wire drawing process may include using a copper rod to pass through a wire drawing die with a gradually varying aperture in a small wire drawing machine to produce a conductive monofilament.

[0038] In some specific embodiments, the diameter Φ of the copper rod used in the wire drawing process may be 1.2 mm. The wire drawing process can produce conductive monofilaments with a diameter Φ as low as 0.1 mm.

[0039] In the above manufacturing method, the annealing process includes annealing treatment and tin plating treatment.

[0040] In some specific embodiments, the temperature of the annealing treatment is 580-600° C. During the annealing treatment, the broken lattices in the conductive monofilament caused by the drawing can be reassembled and arranged.

[0041] In some specific embodiments, the temperature of the tin plating treatment is 380-400° C. The tin plating treatment is generally performed in a tin furnace, and the corrosion resistance and oxidation resistance of the conductive monofilament can be improved by the tin plating treatment.

[0042] Furthermore, the annealing process may also include a sizing treatment. The sizing treatment is generally performed using an eye mold at the end of the tin furnace. The sizing treatment allows the molten tin layer to be evenly coated on the surface of the conductive monofilament.

[0043] In some specific embodiments, the elongation at break of the conductive monofilament obtained through the annealing process can be greater than or equal to 30%.

[0044] In the above manufacturing method, the conductor twisting process may include a wire bundling process and a re-twisting process. The wire bundling process includes twisting the annealed conductive single filaments into conductive strands. The re-twisting process includes twisting the conductive strands into electrical unit conductors.

[0045] In the above manufacturing method, the first wrapping process is generally performed after the re-twisting process is completed.

[0046] In the above manufacturing method, the first wrapping process may specifically include: attaching basalt fiber and reinforcing material to a refractory tape by means of an adhesive, drying to form a refractory tape, and subjecting the refractory tape to a first wrapping process to form a refractory layer on the surface of the electrical unit conductor.

[0047] In some embodiments, the binder comprises epoxy and / or acrylate.

[0048] In some specific embodiments, the binder can be added in the form of a glue. The solid content of the glue is generally controlled to be 5%-30%. Specifically, the solid content of the glue can be 5%, 10%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or other specific values, as well as ranges with any two of the above specific values ​​as endpoints.

[0049] In some specific embodiments, the drying temperature is 65-150° C. For example, the drying temperature can be 65° C., 70° C., 75° C., 80° C., 85° C., 90° C., 95° C., 100° C., 110° C., 120° C., 130° C., 140° C., 150° C., and other specific values, as well as ranges with any two of the above specific values ​​as endpoints.

[0050] In some specific embodiments, the first wrapping process uses a wrapping speed of 600-1800 r / min, for example, 600 r / min, 700 r / min, 800 r / min, 900 r / min, 1000 r / min, 1100 r / min, 1200 r / min, 1300 r / min, 1400 r / min, 1500 r / min, 1600 r / min, 1700 r / min, 1800 r / min, and a range with any two of the above specific values ​​as endpoints.

[0051] In a specific embodiment of the present invention, by controlling the synergy between the solid content of the adhesive, the drying temperature, and the winding speed, the basalt fiber and the reinforcing material can have good mutual adhesion with the refractory belt, while avoiding cracks on the surface of the refractory layer. For example, when forming a refractory layer on the surface of an electrical unit conductor with a diameter of 5-30 mm (or 9-28 mm), the solid content of the adhesive can be 5%-30%, for example, 15-30%, the drying temperature can be 65-150°C, for example, 85-100°C, and the winding speed is generally 600-18000 r / min, for example, 1200-1600 r / min.

[0052] In the above manufacturing method, the first extrusion process can adopt process parameters of a conventional extrusion process.

[0053] In some specific embodiments, the first extrusion process can be performed using a high-speed extruder. The screw diameter of the high-speed extruder can be The high-speed extruder may have an aspect ratio of 25:1.

[0054] In the above manufacturing method, the second wrapping process may adopt process parameters of a conventional wrapping process.

[0055] In some specific embodiments, the wrapping overlap rate of the second wrapping process is generally greater than or equal to 30%.

[0056] In the above manufacturing method, the parameters of the sparse winding process include: the total sparse winding interval is less than or equal to the outer diameter of the shielding monofilament. The sparse winding process generally adopts a unidirectional flexible sparse winding method.

[0057] In the above manufacturing method, the second extrusion process can adopt process parameters of conventional extrusion process.

[0058] In some specific embodiments, the second extrusion process can be carried out using a high-speed extruder. The screw diameter of the high-speed extruder can be The high-speed extruder may have an aspect ratio of 25:1.

[0059] In some specific embodiments, the oxygen index of the sheath layer obtained by the second extrusion process can reach above 35%, and the temperature resistance level of the sheath layer can range from -40°C to +125°C.

[0060] The present invention also provides for the use of the aforementioned water- and fire-resistant cables in underwater equipment, particularly deep-sea equipment. These cables exhibit excellent water and fire resistance and bending flexibility, can continuously conduct electricity in water, withstand prolonged corrosion from seawater fumes and ultraviolet radiation, adapt to the torsional vibrations and frequent tides of the underwater environment, and possess dynamic fire resistance against shock and vibration.

[0061] The beneficial effects of the present invention include:

[0062] The water- and fire-resistant cables provided by the present invention can be used with rated voltages up to 1.8 / 3kV. By improving the cable insulation, sheath, and shielding materials and structural design, the cables' water resistance is enhanced while reducing their weight, and fire resistance is also added. When used in underwater equipment, these water- and fire-resistant cables can improve the long-term operational reliability, safety, and availability of underwater equipment in the event of a fault, and can provide power and information transmission for underwater equipment, particularly deep-sea equipment.

[0063] 2. The batch wrapping quality stability of the fire-resistant layer in the water-resistant and fire-resistant cable provided by the present invention ensures the electrical integrity in the event of a fire inside the equipment, buying time for rescue. It is also used in conjunction with advanced alumina fiber filament fabrics and wrapping technology to further reduce the heating of the conductor during a fire, avoid conductor melting, and slow down the spread of the fire and the resulting losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] FIG1 is a schematic structural diagram of a water- and fire-resistant cable of Example 1.

[0065] DESCRIPTION OF SYMBOLS Electric element conductor 1 , fire-resistant layer 2 , insulating layer 3 , heat-insulating layer 4 , shield layer 5 , sheath layer 6 DETAILED DESCRIPTION

[0066] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0067] Example 1

[0068] This embodiment provides a water- and fire-resistant cable, as shown in Figure 1 , comprising: an electrical unit conductor 1, a fire-resistant layer 2, an insulating layer 3, a thermal insulation layer 4, a shielding layer 5, and a sheath layer 6. The fire-resistant layer 2 is coated on the surface of the electrical unit conductor 1, the insulating layer 3 is coated on the surface of the fire-resistant layer 2, the thermal insulation layer 4 is coated on the surface of the insulating layer 3, the shielding layer 5 is coated on the surface of the thermal insulation layer 4, and the sheath layer 6 is coated on the surface of the shielding layer 5.

[0069] The electrical unit conductor 1 is formed by twisting conductive monofilaments. Specifically, the electrical unit conductor can be formed by twisting several (two or more) conductive monofilaments at a time; or by twisting several conductive monofilaments to form a conductive strand, which is then twisted together to form a plurality of conductive strands.

[0070] Each conductive monofilament has a diameter of 0.18mm-0.5mm and an elongation at break of 30% or greater. The conductive monofilaments are twisted in a regular (1+6+12+18) pattern to form a single conductor, thereby preventing the conductive monofilaments from breaking and piercing the insulation layer 3 during the cable's dynamic operation.

[0071] The surface of the conductive monofilament may be tin-plated, thereby improving the oxidation resistance and corrosion resistance of the electrical unit conductor 1 .

[0072] The conductive strands can be twisted in a (1+6) manner to form an electrical unit conductor. The cross-sectional area of ​​the conductive strands can be 0.5mm 2 -16mm 2 .

[0073] The cross-sectional area of ​​the electrical unit conductor 1 can be 0.5 mm 2 -400mm 2 The conductive strands and / or electrical element conductors 1 may comprise bare copper strands and / or metal alloy coated strands.

[0074] The above-mentioned electrical unit conductor 1 has good bending performance. At the same time, the conductive monofilament contained in the electrical unit conductor 1 has high elongation at break and twisting flexibility, which can greatly improve the reliability of the cable under long-term torsion and vibration conditions in the underwater environment.

[0075] The refractory layer 2 is made of basalt fiber, a reinforcement material, and a refractory tape. The reinforcement material includes mica and / or fiberglass tape. The outer diameter of the basalt fiber is 9 μm to 16 μm. The volume ratio of basalt fiber to reinforcement material is greater than 1:1. The refractory tape can be, for example, a mica tape.

[0076] The refractory layer 2 can be formed by applying basalt fiber and a reinforcing material to the surface of a refractory tape with an adhesive, drying the tape, and then wrapping the tape around the surface of the electrical unit conductor 1 in-line. The adhesive can be epoxy resin and / or acrylate. The adhesive is added in the form of a glue solution, typically with a solids content of 5%-30%.

[0077] Insulation layer 3 is made of cross-linked polyethylene (XLPE), which offers excellent electrical properties, high insulation, and heat and low-temperature resistance. It meets the 240-hour seawater immersion DC stability test and surface resistance test, enhancing the cable's ability to conduct electricity continuously in water. The 240-hour seawater immersion DC stability and surface resistance tests are conducted in accordance with the surface resistance and DC stability test methods in sections 6.6-6.7 of EN50305, "Test Methods for Flame-Retardant Cables for Railway Rolling Stock."

[0078] The thermal insulation layer 4 is made of alumina fiber, specifically alumina fiber filament fabric. Specifically, the thermal insulation layer 4 can be formed by wrapping the alumina fiber filament fabric around the outer surface of the insulating layer 3. The structure of the alumina fiber filament fabric can refer to the structure of the oxide filament fabric described in "Development of Alumina Filament Fabric" (Cotton Textile Technology, 2022, 50(S01):53-56).

[0079] The shielding layer 5 is formed by braiding shielding monofilaments. The outer diameter of the shielding monofilaments is less than or equal to 0.11 mm, and the sum of the intervals between all shielding monofilaments is less than or equal to the outer diameter of the shielding monofilaments. The shielding monofilaments can be formed by unidirectional flexible winding.

[0080] The shielding monofilament used in the present invention comprises nickel-plated carbon fiber or its equivalent fiber (which has comparable mechanical and shielding properties, and is lightweight, thus reducing weight). The strength of the shielding monofilament used in the present invention is comparable to that of conventional tinned copper wire. However, at the same shielding resistance, the weight of the shielding monofilament (nickel-plated carbon fiber) used in the present invention is less than 80% of that of the tinned copper wire. This significantly reduces the weight of the shielding layer 5, facilitating the addition of digital components to underwater equipment and enhancing its intelligence.

[0081] Shielding layer 5 is woven using a unidirectional, flexible, open-wrap pattern. Compared to a bidirectional mesh weave, this prevents stress concentration points on the inner surface of jacket layer 6 when the cable is bent or twisted, making it suitable for use in tidal waters. The total spacing between the open-wrap patterns in shielding layer 5 is less than or equal to the outer diameter of the shielding monofilament.

[0082] The material of the sheath layer 6 includes polyurethane (TPU). The tensile strength of the sheath layer 6 is greater than or equal to 16 MPa, and the elongation at break is greater than or equal to 250%. Polyurethane TPU has excellent mechanical properties and is resistant to environmental corrosion and UV radiation. Compared with the sheath layer made of conventional chloroprene rubber, the sheath layer 6 made of polyurethane TPU in the present invention has better wear resistance and can effectively prevent damage during application. It also has the characteristics of being resistant to seawater corrosion at 70°C for 960 hours, salt spray corrosion at 35°C for 384 hours, and UV radiation for 1440 hours, significantly improving the cable's resistance to environmental corrosion and ensuring the long-term application reliability of the cable.

[0083] The sheath layer's seawater corrosion resistance test procedure involves immersing five test specimens in a seawater solution prepared by adding 30g of salt to every liter of tap water for 960 hours. After immersion, if the change in tensile strength and elongation at break are ≤±40% and ≤±40%, the specimen is considered qualified and resistant to seawater corrosion.

[0084] The sheath layer's salt spray aging test procedure involves testing five specimens in a 5% saline solution at 35°C, alternating between 48-hour immersion and 48-hour drying for a total of 384 hours. Upon completion of the test, if the change in tensile strength of the specimen is ≤±30% and the change in elongation at break is ≤±30%, the specimen is considered qualified and resistant to seawater corrosion.

[0085] The UV-irradiation test for the jacket layer is as follows: 5 samples are tested for 1440 hours. After the test, if the change in tensile strength of the jacket layer does not exceed 30% and the elongation at break does not exceed 30%, the sample is considered qualified and weather-resistant.

[0086] By providing an insulating layer 3 and a sheath layer 6 in the cable, the performance requirements of underwater equipment, especially underwater equipment cabins, for the cable to operate under power in water can be met, and the reliability of the cable in normal working conditions underwater can be ensured.

[0087] By providing a fire-resistant layer 2 made of basalt fiber, the burning and carbonization of the insulating layer 3, which may cause the conductor to short-circuit after being broken by impact and vibration, can be avoided, thus playing the role of emergency insulation. By providing a thermal insulation layer 4 made of alumina fiber, the thermal melting of the electrical unit conductor 1 can be reduced in the event of a fire, and the flame retardant performance can be enhanced and the spread of fire can be slowed down. The fire-resistant layer 2 and the insulating layer 3 can work together to ensure that the water-resistant fire cable meets the comprehensive fire resistance performance of spraying, impact, and vibration. The cable thus obtained has dynamic fire resistance that is resistant to impact and vibration, effectively preventing serious fires caused by internal fires in underwater equipment, equipment failures, and secondary losses caused by underwater recovery.

[0088] Example 2

[0089] This embodiment provides a method for manufacturing the water- and fire-resistant cable of embodiment 1, comprising:

[0090] S1, sequentially performing a wire drawing process, an annealing process, and a conductor twisting process to form an electrical unit conductor;

[0091] (1) Wire drawing process: A copper rod is drawn through a drawing die with a gradually varying aperture in a small wire drawing machine to produce a conductive monofilament. In some embodiments, the diameter of the copper rod used in the wire drawing process may be 1.2 mm. The above-described wire drawing process can produce conductive monofilaments with a diameter as low as 0.1 mm.

[0092] (2) Annealing process: The conductive monofilament obtained in the wire drawing process is subjected to annealing treatment, tinning treatment and sizing treatment in sequence:

[0093] The temperature of the annealing treatment is 580-600°C. During the annealing treatment, the broken lattices in the conductive monofilament caused by wire drawing can be reassembled and arranged;

[0094] The tinning treatment temperature is 380-400℃, usually carried out in a tin furnace. The tinning treatment can improve the corrosion resistance and oxidation resistance of the conductive monofilament.

[0095] The eye mold at the end of the tin furnace is used for sizing treatment, and the molten tin layer can be evenly coated on the surface of the conductive monofilament;

[0096] The elongation at break of the conductive monofilament obtained through the above annealing process is greater than or equal to 30%.

[0097] (3) Conductor twisting process: including wire bundling and re-twisting;

[0098] The wire bundling process involves twisting several conductive monofilaments (usually tinned conductive monofilaments) obtained through annealing into conductive strands (also known as conductor units). The cross-sectional area of ​​the conductive strands is 0.5-16mm. 2 ;

[0099] The conductive strands can be further twisted into electrical unit conductors with a cross-sectional area of ​​50-400 mm 2 .

[0100] S2. Perform a first wrapping process to form a fire-resistant layer on the outer surface of the electrical unit conductor:

[0101] The first wrapping process is as follows: after the re-twisting process is completed, the surface of the electrical unit conductor is covered with a refractory tape, and the covering rate is greater than or equal to 50%;

[0102] The formation process of the refractory strip is as follows: basalt fiber and reinforcement material with a volume ratio greater than 1:1 are attached to the surface of the refractory strip, with a surface coverage rate of 80-95%, and then dried at 65-150°C to form the refractory strip.

[0103] S3, performing a first extrusion process to coat the outer surface of the fire-resistant layer to form an insulating layer:

[0104] The first extrusion process includes: using cross-linked polyethylene (XLPE) as raw material, using a high-speed extruder with a screw diameter of φ80mm-φ90mm and a length-to-diameter ratio of 25:1 to produce insulating material. After extrusion, the insulating material is cooled in a warm water tank, and the moisture on the insulation surface is blown dry in a drying rotary box to obtain an insulated wire core with an insulating layer.

[0105] S4, performing a second wrapping process to wrap the outer surface of the insulation layer to form a heat insulation layer:

[0106] Alumina fiber filament fabric is wrapped around the outer surface of the insulated wire core, with an overlap rate of greater than or equal to 30%, to form a heat insulation layer.

[0107] The formation process of the above-mentioned alumina fiber filament fabric can refer to the manufacturing process of oxide filament fabric recorded in "Development of Alumina Filament Fabric" (Cotton Textile Technology, 2022, 50(S01):53-56).

[0108] In a specific embodiment, since the alumina fiber used in the present invention is well bonded with the resin matrix, during the fabric production process, the reed between the warp frame and the S-shaped warp feeding device can be removed, and a circular reed tooth reed can be used to form an independent warp yarn passage, which is beneficial to reducing fiber friction; free filament weft yarn can be used, and the weft insertion tension is moderate, which is beneficial to the smoothness of the fabric; the damping on the warp frame yarn tube can be removed, and an electronic induction tension adjustment device and a diamond-shaped loom can be used, which is beneficial to ensure uniform warp yarn tension and reduce fiber wear, ensuring that the surface of the finished fabric is flat and smooth, and the texture is clear.

[0109] S5. Perform sparse winding treatment to form a shielding layer on the surface of the thermal insulation layer:

[0110] The sparse winding process includes: using a cage stranding machine to sparsely wind the nickel-plated carbon fiber in a unidirectional manner at a certain angle (also known as unidirectional gap winding) to form a shielding layer.

[0111] S6, performing a second extrusion process to form a sheath layer on the surface of the shielding layer to obtain a water and fire resistant cable;

[0112] The second extrusion process involves extruding the polyurethane (TPU) to form the jacket using a high-speed extruder with a φ100mm screw diameter and a 25:1 aspect ratio. Separate testing of the jacket revealed an oxygen index exceeding 35% and a temperature resistance rating of -40°C to 125°C.

[0113] In the above-described manufacturing method, in step S2, for a certain specification of an electrical unit conductor, the present invention determines the winding speed, the bonding and drying temperature between the basalt fiber and the reinforcing material, the solid content of the adhesive, and the mutual adhesion of the refractory layer based on the relationship between the winding speed, the bonding and drying temperature between the basalt fiber and the reinforcing material, and the solid content of the adhesive. The mutual adhesion is determined based on the absence of visible cracks on the surface of the refractory layer, indicating that the mutual adhesion is acceptable.

[0114] Table 1 shows the relationship between the first wrapping speed, the pasting and baking temperature between the basalt fiber and the reinforcement material, the solid content of the glue and the mutual adhesion of the refractory layer for the first wrapping process of the electrical unit conductors of two specifications.

[0115] Table 1

[0116] It can be seen that for the refractory layer covering the surface of the electrical unit conductor with an outer diameter of 5-30 mm, the wrapping speed is controlled at 800-1600 r / min (further 1200-1600 r / min), the drying temperature is controlled at 65-150°C (further 85-98°C), and the solid content of the glue is 5%-30% (further 17%-28%), which can ensure the mutual adhesion between the basalt fiber, reinforcement material and refractory belt in the refractory layer.

[0117] By adopting the above method to determine the parameters used in the manufacturing process of the refractory layer, the stability of the batch wrapping quality of the refractory layer can be ensured, and the electrical integrity in the event of a fire inside the equipment can be ensured, which can buy time for rescue. In combination with advanced alumina fiber filament fabrics and wrapping technology, it can further reduce the heating of the conductors in the event of a fire, avoid the melting of the conductors, and slow down the spread of the fire and the resulting losses.

[0118] The water and fire resistant cable obtained above meets the result evaluation requirements of the IEC 60332-1-2 single vertical burning test.

[0119] For water and fire resistant cables with an outer diameter of 20mm or less, the cables are subjected to fire and impact during the fire test according to the test method of IEC 60331-2. Starting from the 165th minute of the fire impact test, a water spray test is added for 15 minutes. The spray device and test procedure are in accordance with the EN 50200 standard.

[0120] The EN 50200 fire resistance test result acceptance criteria are: during the test, the conductor does not disconnect, the fuse does not blow, or the circuit breaker does not open.

[0121] For fire-resistant cables with an outer diameter of 20mm or greater, fire is applied to the cables and impacted during the fire process according to the test method of IEC 60331-1. Starting at the 165th minute of the fire impact test, a water spray test is added for 15 minutes. The spray device and test procedures are tested in accordance with BS8491. The above fire resistance tests ensure that the cable does not break down during the fire, impact, water spray, and water spray tests for 180 minutes. This means that the 2A fuse in the test device does not break and the indicator light does not go out.

[0122] The above results prove that the water- and fire-resistant cable provided by the present invention meets the qualification requirements of IEC 60331-2 and IEC 60331-1 standards, has high water resistance and fire resistance, and when applied to underwater equipment, can improve the long-term operation reliability, safety and availability of underwater equipment in fault conditions.

Claims

1. A water- and fire-resistant cable, comprising: Electrical unit conductors, fire-resistant layers, insulation layers, thermal insulation layers, shielding layers and sheath layers; The fire-resistant layer is coated on the surface of the electrical unit conductor, the insulating layer is coated on the surface of the fire-resistant layer, the heat-insulating layer is coated on the surface of the insulating layer, the shielding layer is coated on the surface of the heat-insulating layer, and the sheath layer is coated on the surface of the shielding layer; The refractory layer is formed by overlapping and wrapping a refractory tape on the surface of the insulating layer. The refractory tape is formed by pasting basalt fiber and a reinforcing material on the surface of the refractory tape.

2. The water- and fire-resistant cable according to claim 1, wherein: The outer diameter of the single filament of the basalt fiber is 9 μm-16 μm.

3. The water- and fire-resistant cable according to claim 1, wherein: The reinforcing material includes mica and / or glass fiber tape.

4. The water- and fire-resistant cable according to claim 1, wherein: The coverage rate of the basalt fiber and the reinforcing material on the surface of the refractory belt is 80%-95%.

5. The water- and fire-resistant cable according to claim 1, wherein: The electrical unit conductor is formed by twisting conductive monofilaments, the diameter of each conductive monofilament is 0.18 mm-0.5 mm, and the elongation at break of each conductive monofilament is greater than or equal to 30%.

6. The water- and fire-resistant cable according to claim 1, wherein: The material of the insulating layer includes cross-linked polyethylene.

7. The water- and fire-resistant cable according to claim 1, wherein: The material of the heat insulation layer includes oxide fiber; the material of the heat insulation layer is aluminum oxide fiber filament fabric.

8. The water- and fire-resistant cable according to claim 1, wherein: The shielding layer is formed by weaving shielding monofilaments, the outer diameter of the shielding monofilaments is less than or equal to 0.11 mm, the shielding monofilaments include nickel-plated carbon fibers, and the shielding layer is formed by unidirectional flexible winding; The sum of the intervals of the sparse windings is less than or equal to the outer diameter of the shielding monofilament.

9. The water- and fire-resistant cable according to claim 1, wherein: The material of the sheath layer includes polyurethane.

10. The method for manufacturing a water- and fire-resistant cable according to any one of claims 1 to 9, wherein: The manufacturing method comprises: S1, sequentially performing a wire drawing process, an annealing process, and a conductor twisting process to form an electrical unit conductor; S2. Performing a first wrapping process during the conductor twisting process to form a fire-resistant layer on the outer surface of the electrical unit conductor: S3, performing a first extrusion process to coat the outer surface of the fire-resistant layer to form an insulating layer; S4, performing a second wrapping process to wrap the outer surface of the insulation layer to form a heat insulation layer; S5. Perform sparse winding treatment to form a shielding layer on the surface of the thermal insulation layer: S6. Perform a second extrusion process to form a sheath layer on the surface of the shielding layer to obtain a water- and fire-resistant cable.

11. The manufacturing method according to claim 10, wherein: The annealing process includes annealing treatment and tinning treatment; the temperature of the annealing treatment is 580-600°C; the temperature of the tinning treatment is 380-400°C.

12. The manufacturing method according to claim 10, wherein: The first wrapping process includes: pasting basalt fiber and reinforcing material with an adhesive, drying to form a basalt strip, and subjecting the basalt strip to a first wrapping process to form a refractory layer on the surface of the electrical unit conductor; Wherein, the adhesive comprises epoxy resin and / or acrylate, the drying temperature is 65-150° C., and the first wrapping process adopts a wrapping speed of 600-1800 r / min; The binder is added in the form of glue liquid, and the solid content of the glue liquid is 5%-30%.

13. Use of the water- and fire-resistant cable according to any one of claims 1 to 9 in underwater equipment.

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