Low-voltage fireproof cable and preparation method thereof

Abstract

The invention provides a preparation method for a low-voltage fireproof cable, and the method comprises the steps: carrying out the compressing and twisting of a plurality of strands of high-purity copper wires, obtaining an annealed and compressed conductor, sequentially coating the surface of the annealed and compressed conductor with a functional silica gel tape and a mica tape, and coating the surface of the mica tape with a halogen-free flame-retardant filler to form an insulating layer, thereby obtaining a prefabricated conductor; at least one prefabricated conductor is assembled in a water-blocking tape, microcapsules are filled between the insulating layer and the water-blocking tape, the surface of the water-blocking tape is coated with a waterproof material to form a waterproof layer, and the low-voltage fireproof cable is obtained; a cooling structure is assembled on the outer surface of the low-voltage fireproof cable and comprises a sheath assembly, a water inlet pipe assembly and a water outlet pipe assembly, the water inlet pipe assembly is connected to the sheath assembly and water cooling equipment, the water outlet pipe assembly is connected to the sheath assembly and the water cooling equipment, and the sheath assembly comprises a temperature control system. And the heat dissipation capability of the low-voltage fireproof cable under high temperature and high current load is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of cable materials, and in particular relates to a low-voltage fireproof cable and a preparation method thereof. Background Art

[0002] Low-voltage fire-resistant cables are designed to address potential fire risks associated with the operation of power systems and electrical equipment. Cables operating under high load or fault conditions can overheat locally due to overload, short circuits, or excessive current, potentially causing fires. Especially in confined spaces, underground facilities, and high-rise buildings, a cable failure can rapidly spread fire, causing equipment damage and casualties. Low-voltage fire-resistant cables, designed with halogen-free flame-retardant materials, high-temperature-resistant insulation, and fire-resistant coatings, effectively slow the spread of fire and reduce the release of toxic gases, maximizing personal safety. Furthermore, fire-resistant cables not only reduce electrical system failures caused by fire, but also minimize property damage and ensure the normal operation of power systems and critical equipment. Fire-resistant cables have become an indispensable component of modern buildings and industrial facilities, enhancing the stability and safety of electrical systems while also laying the foundation for achieving higher fire protection standards and compliance requirements.

[0003] During long-term operation or when high currents are present, low-voltage fire-resistant cables, as used in related technologies, continuously generate heat as current flows through the conductors. This heat gradually accumulates, causing the cable temperature to rise. Prolonged exposure to high temperatures accelerates the aging of cable materials, degrades the performance of insulation materials, and increases the risk of cable failure. Excessive temperatures can also cause the cable's outer sheath and insulation to melt or burn, potentially causing a fire. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a low-voltage fireproof cable and a preparation method thereof, aiming to solve the problem of insufficient heat dissipation capacity of the low-voltage fireproof cable under high current load and long-term operation.

[0005] To solve the above problems, the present invention proposes a method for preparing a low-voltage fireproof cable, comprising the following steps: S1. Compressing and twisting high-purity multiple copper wires to obtain an annealed compacted conductor, and sequentially coating the surface of the annealed compacted conductor with a functional silicone tape and a mica tape, wherein the functional silicone tape includes a toxic adsorption monomer; S2. Coating a halogen-free flame-retardant filler on the surface of a mica tape to form an insulating layer to obtain a prefabricated conductor, assembling at least one prefabricated conductor in a water-blocking tape, filling microcapsules between the insulating layer and the water-blocking tape, and coating the surface of the water-blocking tape with a waterproof material to form a waterproof layer to obtain a low-voltage fire-resistant cable; S3. A cooling structure is assembled on the outer surface of the low-voltage fire-resistant cable. The cooling structure includes a sheath assembly, a water inlet pipe assembly, and a water outlet pipe assembly. The water inlet pipe assembly is respectively connected to the sheath assembly and the water-cooling equipment. The water outlet pipe assembly is respectively connected to the sheath assembly and the water-cooling equipment. The sheath assembly includes a temperature control system. The temperature control system is used to adjust the flow rate of the coolant of the water-cooling equipment in the water inlet pipe assembly.

[0006] In some embodiments, step S1 includes: S1.1. High-purity multi-strand copper wires are twisted in the same direction and compressed at a compression ratio of 85-90% to form an annealed compressed conductor. The annealed compressed conductor is placed in an annealing furnace and annealed at 400-420°C under an inert atmosphere for 5-8 minutes. S1.2. Wrap double layers of functional silicone tape alternately around the surface of the annealed and compressed conductor. The width of the functional silicone tape is 20 mm, the thickness of each layer is 0.2 mm, and the overlap ratio is set to 10-12%. S1.3. Wrap the functional silicone tape with five layers of mica tape with a thickness of 0.15-0.2 mm, with an overlap rate of 15-20%. During the wrapping process, apply an organic platinum catalyst to the gaps in the mica tape.

[0007] In some embodiments, in step S1, the toxic adsorption monomer includes at least one of magnesium-aluminum layered double hydroxide, magnesium-aluminum hydrotalcite, and amino-modified porous silica, and the organic platinum catalyst includes at least one of divinylcyclosiloxane complexed with platinum, Spier platinum catalyst, and tris(1,1,3,3-tetramethyldivinyldisiloxane) platinum complex.

[0008] In some embodiments, step S2 includes: S2.1. Coating the surface of the mica tape with a halogen-free flame-retardant insulating material. Mixing is performed in a twin-screw blender. The temperature is set to 150°C in the first section, 170°C in the second section, and 185°C in the third section. The screw speed is 60-80 rpm, and the shearing time is 8-10 minutes. The material is devolatilized through a vent and then extruded and coated to form an insulating layer to obtain a prefabricated conductor. S2.2. Assemble at least one prefabricated conductor in a water-blocking tape, and use vacuum-assisted pressure to infuse microcapsules between the outer surface of the prefabricated conductor and the water-blocking tape. After filling, use a waterproof material for single-layer extrusion coating. The extrusion temperature zone is 140°C in the first section, 160°C in the second section, and 175°C in the third section. The die temperature is 190°C, and the pulling speed is controlled at 10~12 m / min. After cooling, a waterproof layer is formed to obtain a low-voltage fire-resistant cable.

[0009] In some embodiments, in step S2, The halogen-free flame-retardant insulating material comprises an insulating body, a flame retardant, and an additive, wherein the insulating body comprises at least one of cross-linked polyethylene, low-density polyethylene, environmentally friendly polyvinyl chloride, and vinyl acetate-ethylene copolymer; the flame retardant comprises at least one of magnesium hydroxide, aluminum hydroxide, and melamine polyphosphate; and the additive comprises at least one of anthraquinone ketones, chlorinated bio-esters, and maleic anhydride grafted polyethylene; The microcapsules include at least one of self-repairing microcapsules, adsorption microcapsules, and temperature-controlling microcapsules. The self-repairing microcapsules include bisphenol A epoxy resin, aliphatic amine curing agent, and melamine-formaldehyde resin. The adsorption microcapsules include double hydroxide and polyurea / polyimide copolymer. The temperature-controlling microcapsules include zinc nanopowder and polymethyl methacrylate. The waterproof material includes at least one of ceramic polyolefin composite material, high molecular sodium polyacrylate, and functional fluorosilicone rubber coating material.

[0010] In some embodiments, step S3 includes: S3.1. The jacket assembly of the cooling structure includes an inner jacket and an outer jacket, the water inlet pipe assembly includes an inner water inlet pipe and an outer water inlet pipe, and the water outlet pipe assembly includes an inner water outlet pipe and an outer water outlet pipe. The inner jacket is sleeved on the outer surface of the waterproof layer, and the outer jacket is sleeved on the outer surface of the inner jacket. A breathable and waterproof membrane is provided between the inner and outer jackets. One end of the inner water inlet pipe is connected to the water cooling device and the other end is connected to the water inlet of the inner jacket. One end of the inner water outlet pipe is connected to the water cooling device and the other end is connected to the water outlet of the inner jacket. One end of the outer water inlet pipe is connected to the water cooling device and the other end is connected to the water inlet of the outer jacket. One end of the outer water outlet pipe is connected to the water cooling device and the other end is connected to the water inlet of the outer jacket. One end of the outer water outlet pipe is connected to the water cooling device and the other end is connected to the water outlet of the outer jacket. S3.2. The water cooling equipment is provided with a flow control component, which is connected to the inner water outlet pipe and the outer water outlet pipe. When the temperature detected by the temperature control system exceeds the set range, the flow control component connected to the temperature control system signal adjusts the flow of the water cooling equipment in the inner water outlet pipe and the outer water outlet pipe.

[0011] In some embodiments, in step S3, the sheath assembly is made of a sheath material, the sheath material includes at least one of graphene composite material, aluminum nitride, aluminum powder, and copper powder, and the air-permeable and water-impermeable membrane includes at least one of polytetrafluoroethylene, polyamide fiber, and polyurethane.

[0012] The present invention provides a low-voltage fireproof cable, which is manufactured by the above-mentioned method for preparing a low-voltage fireproof cable.

[0013] Compared with the prior art, the low-voltage fireproof cable and its preparation method in the present invention have the following beneficial effects: The design of low-voltage fire-resistant cables utilizes high-temperature protection technologies such as halogen-free flame-retardant materials, mica tape coatings, and functional silicone tapes. These technologies effectively enhance the cables' fire resistance, allowing them to maintain power or signal transmission functions for extended periods during fire conditions. A cooling structure, including a jacket assembly, water inlet and outlet pipe assemblies, and a temperature control system, is installed on the cable's outer surface to effectively address the problem of insufficient heat dissipation. The cooling system regulates the cable's temperature by circulating coolant, ensuring it remains within a safe temperature range under high temperatures or high loads, thereby preventing electrical failures or fires caused by overheating. The temperature control system, combined with flow control components, automatically adjusts the coolant flow, ensuring more stable and efficient cooling under varying conditions and loads. This further enhances the cable's heat dissipation capabilities and, working in conjunction with the cable's fire resistance, improves the safety and stability of low-voltage fire-resistant cables under high temperatures and high current loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic flow chart of a method for preparing a low-voltage fireproof cable according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the connection between a low-voltage fireproof cable and a water cooling device according to an embodiment of the present invention; Figure 3 The figure is a schematic structural diagram of a low-voltage fireproof cable according to an embodiment of the present invention.

[0015] Description of labels: 100. Low-voltage fireproof cable; 1. Optical fiber unit; 2. Annealed compressed conductor; 3. Functional silicone tape; 4. Mica tape; 5. Insulation layer; 6. Microcapsule; 7. Water-blocking tape; 8. Waterproof layer; 9. Inner sheath; 10. Water storage space; 11. Outer sheath; 21. External water inlet pipe; 22. Internal water inlet pipe; 31. External water pipe; 32. Internal water outlet pipe; 400. Water cooling equipment; 41. Flow control element. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] The present invention provides a method for preparing a low-voltage fire-resistant cable 100, comprising the following steps: S1. Compress and twist high-purity copper wires to form an annealed compact conductor 2. A functional silicone tape 3 and a mica tape 4 are sequentially coated on the surface of the annealed compact conductor 2. The functional silicone tape 3 includes a toxic adsorption monomer. The toxic adsorption monomer includes at least one of a magnesium-aluminum layered double hydroxide, a magnesium-aluminum hydrotalcite, and an amino-modified porous silica.

[0018] Step S1 includes: S1.1. High-purity multi-strand copper wires are compressed by twisting them in the same direction with a compression ratio of 85-90% to form an annealed compressed conductor 2. The annealed compressed conductor 2 is then placed in an annealing furnace and annealed at 400-420°C under an inert atmosphere for 5-8 minutes.

[0019] Processing copper wire by twisting it in the same direction and compacting it effectively improves the conductor's electrical conductivity and mechanical strength while ensuring its flexibility and reliability. By controlling the compaction ratio between 85% and 90%, the conductor's porosity can be effectively reduced, enhancing the cable's thermal conductivity and reducing heat loss during current flow. Next, the annealed compacted conductor 2 is sent to an annealing furnace for annealing at 400-420°C in an inert atmosphere. This process restores the copper wire's lattice structure through heating, thereby reducing stress generated during processing and improving the conductor's ductility and oxidation resistance. After annealing, the copper conductor's electrical conductivity is improved and its corrosion resistance is enhanced, helping to extend the cable's service life and stability. During the annealing process, the inert atmosphere effectively prevents oxidation, ensuring that the copper conductor's surface does not oxidize, maintaining its conductive properties. This annealing process also helps provide a more uniform and smooth surface for the subsequent coating step, facilitating the attachment of subsequent materials.

[0020] S1.2. Wrap two layers of functional silicone tape 3 alternately around the surface of the annealed, compacted conductor 2. The functional silicone tape 3 is 20 mm wide, with a single layer thickness of 0.2 mm, and the overlap ratio is set to 10-12%. Multiple annealed, compacted conductors 2 can be intermixed with optical fiber units 1.

[0021] The double-layer, staggered functional silicone tape 3 wrapped around the copper conductor not only provides excellent insulation but also boasts high-temperature resistance and aging resistance, thereby enhancing the cable's safety and durability. Silicone tape was chosen for its excellent flexibility and wide temperature range, capable of withstanding temperatures exceeding 200°C. By setting the functional silicone tape 3 to a width of 20 mm, a thickness of 0.2 mm, and a 10-12% overlap ratio, the insulation and conductivity of each layer are guaranteed to interact independently, preventing current leakage or short circuits in the cable. Furthermore, toxic adsorbent monomers (such as magnesium-aluminum layered double hydroxide, magnesium-aluminum hydrotalcite, and amino-modified porous silica) incorporated into the tape absorb and neutralize toxic gases (such as hydrogen chloride and carbon monoxide) in the cable's surroundings during operation, further enhancing the cable's safety in the event of fire or overheating. The combination of silicone tape and these adsorbents effectively mitigates the hazards of toxic gases in the event of an accident, protecting the surrounding environment and personnel.

[0022] S1.3. Wrap the functional silicone tape with five layers of mica tape (4) with a thickness of 0.15-0.2 mm, with an overlap ratio of 15-20%. During the wrapping process, apply an organic platinum catalyst to the gaps in the mica tape (4). The organic platinum catalyst includes at least one of a divinylcyclosiloxane-platinum complex, a Spiel platinum catalyst, and a tris(1,1,3,3-tetramethyldivinyldisiloxane)platinum complex.

[0023] Mica tape 4 is a common high-temperature insulation material with excellent fire resistance and thermal stability, capable of withstanding long-term operation at high temperatures. Five layers of mica tape 4 are wrapped around the functional silicone tape, forming an insulating protective layer through overlapping wrapping. This gives the cable enhanced fire resistance and mechanical strength. The overlap ratio of the mica tape 4 is controlled between 15% and 20%, ensuring a dense and crack-resistant insulation layer 5 on the cable surface, thereby protecting the cable from mechanical damage and chemical attack from the external environment. An organic platinum catalyst is applied to the gaps in the mica tape 4 to promote crosslinking of the cable's insulation layer 5 and enhance the cable's stability at high temperatures. Divinylcyclosiloxane, combined with a platinum complex and Spiel platinum catalyst, promotes crosslinking of the silicone material, enhancing its heat resistance and insulation properties. Furthermore, the platinum complex tris(1,1,3,3-tetramethyldivinyldisiloxane) also catalyzes the interface between the mica tape 4 and the silicone tape, thereby improving the overall performance of the cable. The role of the organic platinum catalyst is not limited to improving the heat resistance of the cable insulation layer 5, but can also effectively slow down the release of toxic gases in the event of fire or overheating, preventing cable failure or fire spread caused by high temperature.

[0024] S2. A halogen-free flame-retardant filler is coated on the surface of the mica tape 4 to form an insulating layer 5 to obtain a prefabricated conductor. At least one prefabricated conductor is assembled in a water-blocking tape 7. Microcapsules 6 are filled between the insulating layer 5 and the water-blocking tape 7. A waterproof material is coated on the surface of the water-blocking tape 7 to form a waterproof layer 8 to obtain a low-voltage fire-resistant cable 100.

[0025] In step S2, The halogen-free flame-retardant insulating material comprises an insulating body, a flame retardant, and an additive, wherein the insulating body comprises at least one of cross-linked polyethylene, low-density polyethylene, environmentally friendly polyvinyl chloride, and vinyl acetate-ethylene copolymer; the flame retardant comprises at least one of magnesium hydroxide, aluminum hydroxide, and melamine polyphosphate; and the additive comprises at least one of anthraquinone ketones, chlorinated bio-esters, and maleic anhydride grafted polyethylene; The microcapsule 6 includes at least one of a self-repairing microcapsule 6, an adsorption microcapsule 6, and a temperature control microcapsule 6. The self-repairing microcapsule 6 includes bisphenol A epoxy resin, a fatty amine curing agent, and melamine-formaldehyde resin. The adsorption microcapsule 6 includes double hydroxide and polyurea / polyimide copolymer. The temperature control microcapsule 6 includes zinc nanopowder and polymethyl methacrylate. The waterproof material includes at least one of ceramic polyolefin composite material, high molecular sodium polyacrylate, and functional fluorosilicone rubber coating material.

[0026] Step S2 includes: S2.1. The surface of the mica tape 4 is coated with a halogen-free flame-retardant insulating material. The mixing is carried out in a twin-screw blender. The temperature is set to 150°C in the first section, 170°C in the second section, and 185°C in the third section. The screw speed is 60-80 rpm and the shearing time is 8-10 minutes. The material is devolatilized through the exhaust port and then extruded and coated to form an insulating layer 5 to obtain a prefabricated conductor.

[0027] Coating the surface of mica tape 4 with halogen-free flame-retardant insulation material significantly improves the cable's fire resistance and thermal stability. The blend primarily consists of a halogen-free insulation base, flame retardants, and additives. Halogen-free insulation (such as cross-linked polyethylene, low-density polyethylene, or environmentally friendly polyvinyl chloride) offers excellent insulation properties, high-temperature resistance, and flexibility. Mixing and high-temperature extrusion in a twin-screw blender ensures material uniformity and high dielectric strength, thereby enhancing cable safety. Flame retardants (such as magnesium hydroxide, aluminum hydroxide, or melamine polyphosphate) not only effectively absorb heat and reduce temperatures in a fire, but also generate inert gases (such as water vapor) during flame propagation, slowing flame spread and improving the cable's fire resistance. These flame retardants, combined with halogen-free insulation, avoid the toxic gas release associated with halogen-based materials in traditional cables. Furthermore, additives such as anthraquinone ketones, chlorinated bio-esters, and maleic anhydride-grafted polyethylene further enhance the cable's antioxidant, aging, and UV resistance, extending its service life. During the extrusion process, the set temperature range (150°C to 185°C), moderate screw speed (60-80 rpm), and shear time (8-10 minutes) help to uniformly mix the materials and ensure the quality and stability of the insulation layer 5.

[0028] S2.2. Assemble at least one prefabricated conductor in the water-blocking tape 7, and use vacuum-assisted pressure-injection microcapsules 6 between the outer surface of the prefabricated conductor and the water-blocking tape 7. After the filling is completed, use waterproof material for single-layer extrusion coating. The extrusion temperature zone is 140°C in the first section, 160°C in the second section, and 175°C in the third section. The die head temperature is 190°C, and the pulling speed is controlled to be 10~12 m / min. After cooling, a waterproof layer 8 is formed to obtain a low-voltage fire-resistant cable 100.

[0029] Assembling prefabricated conductors within a water-blocking tape 7 and infusing microcapsules 6 via vacuum-assisted pressure infusion improves the cable's reliability and long-term stability in humid environments. Microcapsules 6 include self-healing microcapsules 6, adsorption microcapsules 6, and temperature-control microcapsules 6. Each microcapsule 6 performs a different function, forming a multifunctional protection mechanism. Self-healing microcapsules 6, containing bisphenol A epoxy resin and a fatty amine curing agent, automatically release a repair agent when cracks or damage occur in the cable, filling the damaged area and restoring the cable's structural integrity, thereby preventing damage-related cable failure or short circuits. Adsorption microcapsules 6, made of double hydroxide and polyurea / polyimide copolymers, absorb toxic gases (such as hydrogen chloride and benzene) generated during fires, providing additional protection against harmful gas accumulation. Temperature-control microcapsules 6, containing zinc nanopowder and polymethyl methacrylate, respond to temperature changes and regulate their internal chemical reactions, helping the cable maintain stability at high temperatures and preventing overheating. After infusion, the microcapsules are extruded over the cable in a single layer with a waterproof material. The waterproof material typically consists of at least one of a ceramicized polyolefin composite, sodium polyacrylate, or a fluorosilicone rubber coating. It exhibits waterproof, high-temperature, and UV-resistant properties. Through an extrusion process (set at a temperature of 140°C to 190°C), the waterproof material is evenly coated on the outer surface of the prefabricated conductor, forming an effective waterproof layer 8 that prevents moisture from entering the cable and maintains long-term stable operation. The extrusion temperature of the waterproof layer 8 is controlled between 140°C and 175°C, ensuring that the waterproof material fully melts and forms a good bond with the cable insulation layer 5. A die temperature of 190°C and a pulling speed of 10 to 12 meters per minute ensure that the waterproof layer 8 maintains sufficient toughness and tensile strength after cooling, while also maintaining waterproof performance.

[0030] S3. Assemble a cooling structure on the outer surface of the low-voltage fire-resistant cable 100. The cooling structure includes a sheath assembly, a water inlet pipe assembly, and a water outlet pipe assembly. The water inlet pipe assembly is connected to the sheath assembly and the water cooling device 400, respectively. The water outlet pipe assembly is connected to the sheath assembly and the water cooling device 400, respectively. The sheath assembly includes a temperature control system for regulating the flow of coolant from the water cooling device 400 in the water inlet pipe assembly. The sheath material includes at least one of a graphene composite material, aluminum nitride, aluminum powder, and copper powder.

[0031] Step S3 includes: S3.1. The jacket assembly of the cooling structure includes an inner jacket 9 and an outer jacket 11. The water inlet pipe assembly includes an inner water inlet pipe 22 and an outer water inlet pipe 21. The water outlet pipe assembly includes an inner water outlet pipe 32 and an outer water outlet pipe 31. The inner jacket 9 is sleeved on the outer surface of the waterproof layer 8. The outer jacket 11 is sleeved on the outer surface of the inner jacket 9. An air-permeable and water-impermeable membrane is provided between the inner jacket 9 and the outer jacket 11. One end of the inner water inlet pipe 22 is connected to the water cooling device 400, and the other end is connected to the outer jacket 11. The inner jacket 9 is connected to the water inlet; the inner water outlet pipe 32 is connected to the water cooling device 400 at one end and to the water outlet of the inner jacket 9 at the other end; the outer water inlet pipe 21 is connected to the water cooling device 400 at one end and to the water inlet of the outer jacket 11 at the other end; the outer water pipe 31 is connected to the water cooling device 400 at one end and to the water outlet of the outer jacket 11 at the other end; the air-permeable and water-impermeable membrane comprises at least one of polytetrafluoroethylene, polyamide fiber, and polyurethane. A water storage space 10 can be enclosed between the inner jacket 9 and the outer jacket 11, and the water inlet pipe assembly and the water outlet pipe assembly can be connected to the water storage space 10.

[0032] The primary technical benefit of this step is the dual-layer sheath design, which provides efficient thermal management and physical protection while ensuring coolant flow and preventing moisture penetration. An inner sheath 9 is attached to the outer surface of the cable's waterproof layer 8, while an outer sheath 11 wraps around the outer layer of the inner sheath 9, creating a dual-layer protection structure that effectively prevents external physical damage and environmental contamination. A breathable, water-tight membrane is placed between the two sheath layers, effectively preventing moisture from entering the cable while allowing air and water vapor to flow through, maintaining stable operation of the cooling system. The choice of a breathable, water-tight membrane (such as polytetrafluoroethylene, polyamide fiber, or polyurethane) ensures a high degree of water resistance, maintaining cable waterproofing while allowing gas to pass through, preventing short circuits or damage caused by moisture accumulation within the cable. This design effectively reduces the risk of intrusion due to ambient humidity or moisture. The membrane material used, such as polytetrafluoroethylene, has an extremely low surface energy, making it impervious to moisture but allowing air and water vapor to pass through, thus maintaining the heat exchange environment required by the cooling system. The coolant piping system connects the inner and outer water inlet pipes 21 and outlet pipes, ensuring that the coolant flows evenly inside and outside the cable, effectively removing heat from the cable and preventing overheating. The coolant piping connection design is simple and efficient, making maintenance and management of the cooling system more convenient.

[0033] S3.2. The water cooling device 400 is provided with a flow control component, which is connected to the inner water outlet pipe 32 and the outer water pipe 31. When the temperature detected by the temperature control system exceeds the set range, the flow control component connected to the temperature control system signal adjusts the flow in the inner water outlet pipe 32 and the outer water pipe 31 of the water cooling device 400.

[0034] The technical effect of this step is that the flow control unit and the temperature control system work together to automatically adjust the coolant flow rate, ensuring a stable cable temperature under all operating conditions. After receiving a regulation signal from the temperature control system, the flow control unit automatically adjusts the coolant flow rate by adjusting the valve, effectively regulating the flow rate of the coolant in the inner outlet pipe 32 and the outer outlet pipe 31, ensuring that the cable maintains an ideal temperature under varying loads. The temperature control system monitors the cable's operating temperature in real time. When the temperature exceeds a set safety range, the system automatically issues a signal to adjust the coolant flow rate to enhance cooling. If the cable temperature is too high, the flow control unit opens the valve, increasing the coolant flow rate to rapidly cool the cable and prevent overheating from causing short circuits, fires, or other electrical failures. This flow control unit not only provides efficient flow regulation but also self-adjusts according to changes in the coolant flow rate to ensure optimal flow. Through fine-tuning of the flow control, the cooling system achieves more precise temperature management in extreme environments, enabling the cable to operate stably and for extended periods under high loads without overheating. Compared to traditional manually adjusted cooling systems, this design uses automated flow control to achieve a linkage between the temperature control system and the flow control device, providing more intelligent and efficient temperature management in complex and high-load working environments. This design significantly improves the safety and reliability of the cable and reduces the need for manual intervention.

[0035] When the cable temperature exceeds the preset range, the built-in temperature control system immediately detects the temperature change. The temperature control system collects data in real time through temperature sensors (which can be fiber-optic temperature control modules) connected to the cable, and this temperature information is transmitted to the central control unit. If the temperature exceeds the set upper limit, the temperature control system automatically issues an adjustment signal to the connected flow control unit. The temperature control system and flow control unit maintain a real-time connection and data transmission via electronic signals or communication protocols (such as MODBUS, CAN bus, etc.). The signal linkage between the temperature control system and the flow control unit ensures that the coolant flow rate can be adjusted quickly in the event of abnormal cable temperature, effectively reducing the risk of overheating.

[0036] When the temperature control system sends a signal, the flow control unit receives this information and begins adjusting the flow rate according to the preset regulation logic. The microprocessor or control circuit inside the flow control unit analyzes the temperature control system's signal and determines whether to increase or decrease the coolant flow rate based on the current temperature exceedance and cooling requirements. For example, if the temperature rises significantly, the flow control unit will adjust the flow rate according to the set response mode to ensure that sufficient coolant flows through the cable. The microprocessor built into the flow control unit can accurately adjust the flow rate according to different temperature changes, achieving automated and precise control, avoiding energy waste or equipment damage caused by overcooling or insufficient cooling.

[0037] The flow control component begins to change the flow rate of the coolant in the inner outlet pipe 32 and the outer outlet pipe 31 through a regulating valve or a proportional control device. These control devices include electric regulating valves, proportional flow regulating valves, etc., which can accurately switch or adjust the opening and closing degree of the valve according to the input of the temperature control signal. In this way, the flow control component can adjust the flow rate of the coolant in real time, increasing or decreasing the circulation volume of the coolant. For example, when the temperature is higher than the set range, the flow control component will automatically open the regulating valve to increase the flow rate of the coolant; on the contrary, if the temperature drops to the normal range, the flow rate will be adjusted to a lower level. The use of electric regulating valves and proportional control technology makes the adjustment of the coolant flow rate more precise, can quickly respond to the instructions of the temperature control system, improve cooling efficiency and save energy.

[0038] After flow adjustment, the system continuously monitors changes in coolant flow and temperature. A real-time feedback mechanism is maintained between the temperature control system and the flow control unit to ensure accurate flow adjustment. Once the coolant flow reaches the new preset range, the temperature control system continues to monitor changes in cable temperature and issues adjustment instructions to the flow control unit. If the temperature remains too high, the flow control unit will further increase the flow rate, and vice versa. This process is a dynamic adjustment process that ensures stable operation of the cable within the optimal temperature range. Through real-time feedback and control mechanisms, the system can dynamically adjust the coolant flow rate to ensure that the temperature remains within the optimal range, preventing the impact of excessively high or low temperatures on the safe operation of the cable.

[0039] The present invention provides a low-voltage fire-resistant cable 100 , which is manufactured by a method for preparing the low-voltage fire-resistant cable 100 .

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a low-voltage fireproof cable, characterized in that the steps include: S1. Compressing and twisting high-purity multiple copper wires to obtain an annealed compacted conductor, and sequentially coating the surface of the annealed compacted conductor with a functional silicone tape and a mica tape, wherein the functional silicone tape includes a toxic adsorption monomer; S2. Coating a halogen-free flame-retardant filler on the surface of a mica tape to form an insulating layer to obtain a prefabricated conductor, assembling at least one prefabricated conductor in a water-blocking tape, filling microcapsules between the insulating layer and the water-blocking tape, and coating the surface of the water-blocking tape with a waterproof material to form a waterproof layer to obtain a low-voltage fire-resistant cable, wherein the microcapsules are used to improve the fire resistance of the low-voltage fire-resistant cable and reduce toxic gases; S3. A cooling structure is assembled on the outer surface of the low-voltage fire-resistant cable. The cooling structure includes a sheath assembly, a water inlet pipe assembly, and a water outlet pipe assembly. The water inlet pipe assembly is respectively connected to the sheath assembly and the water-cooling equipment. The water outlet pipe assembly is respectively connected to the sheath assembly and the water-cooling equipment. The sheath assembly includes a temperature control system. The temperature control system is used to adjust the flow rate of the coolant of the water-cooling equipment in the water inlet pipe assembly.

2. The method for preparing a low-voltage fireproof cable according to claim 1, characterized in that: Step S1 includes: S1.

1. High-purity multi-strand copper wires are twisted in the same direction and compressed at a compression ratio of 85-90% to form an annealed compressed conductor. The annealed compressed conductor is placed in an annealing furnace and annealed at 400-420°C under an inert atmosphere for 5-8 minutes. S1.

2. Wrap double layers of functional silicone tape alternately around the surface of the annealed and compressed conductor. The width of the functional silicone tape is 20 mm, the thickness of each layer is 0.2 mm, and the overlap ratio is set to 10-12%. S1.

3. Wrap the functional silicone tape with five layers of mica tape with a thickness of 0.15-0.2 mm, with an overlap rate of 15-20%. During the wrapping process, apply an organic platinum catalyst to the gaps in the mica tape.

3. The method for preparing a low-voltage fireproof cable according to claim 2, characterized in that: In step S1, the toxic adsorption monomer includes at least one of magnesium-aluminum layered double hydroxide, magnesium-aluminum hydrotalcite, and amino-modified porous silica, and the organic platinum catalyst includes at least one of divinylcyclosiloxane-coated platinum complex, Spier platinum catalyst, and tris(1,1,3,3-tetramethyldivinyldisiloxane) platinum complex.

4. The method for preparing a low-voltage fireproof cable according to claim 1, characterized in that: Step S2 includes: S2.

1. Coating the surface of the mica tape with a halogen-free flame-retardant insulating material. Mixing is performed in a twin-screw blender. The temperature is set at 150°C in the first section, 170°C in the second section, and 185°C in the third section. The screw speed is 60-80 rpm, and the shearing time is 8-10 minutes. The material is devolatilized through a vent and then extruded and coated to form an insulating layer to obtain a prefabricated conductor. S2.

2. Assemble at least one prefabricated conductor in a water-blocking tape, and use vacuum-assisted pressure to infuse microcapsules between the outer surface of the prefabricated conductor and the water-blocking tape. After filling, use a waterproof material for single-layer extrusion coating. The extrusion temperature zone is 140°C in the first section, 160°C in the second section, and 175°C in the third section. The die temperature is 190°C, and the pulling speed is controlled at 10~12 m / min. After cooling, a waterproof layer is formed to obtain a low-voltage fire-resistant cable.

5. The method for preparing a low-voltage fireproof cable according to claim 4, characterized in that: In step S2, The halogen-free flame-retardant insulating material comprises an insulating body, a flame retardant, and an additive, wherein the insulating body comprises at least one of cross-linked polyethylene, low-density polyethylene, environmentally friendly polyvinyl chloride, and vinyl acetate-ethylene copolymer; the flame retardant comprises at least one of magnesium hydroxide, aluminum hydroxide, and melamine polyphosphate; and the additive comprises at least one of anthraquinone ketones, chlorinated bio-esters, and maleic anhydride grafted polyethylene; The microcapsules include at least one of self-repairing microcapsules, adsorption microcapsules, and temperature-controlling microcapsules. The self-repairing microcapsules include bisphenol A epoxy resin, aliphatic amine curing agent, and melamine-formaldehyde resin. The adsorption microcapsules include double hydroxide and polyurea / polyimide copolymer. The temperature-controlling microcapsules include zinc nanopowder and polymethyl methacrylate. The waterproof material includes at least one of ceramic polyolefin composite material, high molecular sodium polyacrylate, and functional fluorosilicone rubber coating material.

6. The method for preparing a low-voltage fireproof cable according to claim 1, characterized in that: Step S3 includes: S3.

1. The jacket assembly of the cooling structure includes an inner jacket and an outer jacket, the water inlet pipe assembly includes an inner water inlet pipe and an outer water inlet pipe, and the water outlet pipe assembly includes an inner water outlet pipe and an outer water outlet pipe. The inner jacket is sleeved on the outer surface of the waterproof layer, and the outer jacket is sleeved on the outer surface of the inner jacket. A breathable and waterproof membrane is provided between the inner and outer jackets. One end of the inner water inlet pipe is connected to the water cooling device and the other end is connected to the water inlet of the inner jacket. One end of the inner water outlet pipe is connected to the water cooling device and the other end is connected to the water outlet of the inner jacket. One end of the outer water inlet pipe is connected to the water cooling device and the other end is connected to the water inlet of the outer jacket. One end of the outer water outlet pipe is connected to the water cooling device and the other end is connected to the water inlet of the outer jacket. One end of the outer water outlet pipe is connected to the water cooling device and the other end is connected to the water outlet of the outer jacket. S3.

2. The water cooling equipment is provided with a flow control component, which is connected to the inner water outlet pipe and the outer water outlet pipe. When the temperature detected by the temperature control system exceeds the set range, the flow control component connected to the temperature control system signal adjusts the flow of the water cooling equipment in the inner water outlet pipe and the outer water outlet pipe.

7. The method for preparing a low-voltage fireproof cable according to claim 6, characterized in that: In step S3, the sheath assembly is made of a sheath material, the sheath material includes at least one of a graphene composite material, aluminum nitride, aluminum powder, and copper powder, and the air-permeable and water-impermeable membrane includes at least one of polytetrafluoroethylene, polyamide fiber, and polyurethane.

8. A low voltage fireproof cable, characterized in that: The low-voltage fireproof cable is manufactured by the preparation method of any one of claims 1 to 7.

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