A high flame-retardant and heat-resistant cable

Abstract

This utility model discloses a high flame-retardant and heat-resistant cable, comprising a cable core and an outer sheath wrapped around the cable core. The cable core includes several conductors and filler material, with the filler material filling the gaps between the conductors. The outer sheath has a multi-layer structure, with the outermost layer being an expanded graphite coating. This utility model has a reasonable structural design and the following beneficial effects: the expanded graphite coating forms a continuous and dense structure through a spraying process; upon heating, the expanded graphite can rapidly expand to form a heat-insulating layer, effectively blocking external flames and heat conduction; and in the early stages of a fire, it quickly isolates oxygen from flammable gases, reducing the possibility of combustion and delaying the spread of fire.

Description

Technical Field

[0001] This utility model relates to the field of cable technology, and in particular to a high flame-retardant and heat-resistant cable. Background Technology

[0002] With the increasing complexity of modern industrial systems and the acceleration of urbanization, power transmission systems face higher requirements for safety and stability. In special industrial settings such as chemical, petroleum, and mining, flammable and explosive environments pose a severe challenge to the flame-retardant properties of cables—traditional cables are prone to ignition and spread at high temperatures, releasing large amounts of toxic fumes during combustion, which not only leads to power outages but also exacerbates fire hazards and hinders emergency rescue. Meanwhile, the iterative upgrades of electronic equipment are driving the development of high-performance cables, highlighting the increasing inadequacies of traditional materials in terms of high-temperature resistance, weather resistance, and environmental friendliness. In the field of public safety, fire hazards in commercial buildings, residential buildings, and industrial plants require cables to have reliable flame-retardant protection capabilities. The traditional method of using expanded graphite tape to cover cables has significant drawbacks: it is easily damaged by dragging and friction during installation, and the tape's service life is difficult to meet the cable design requirement of more than 35 years, especially in harsh environments such as open air and underwater, where the risk of failure is even higher. In response to global sustainable development goals, the cable industry urgently needs environmentally friendly solutions. Halogen-free, low-smoke, long-life, and highly reliable flame-retardant cables have become a market necessity. However, the limitations of existing technologies in material combinations and process design make the development of a new type of cable that combines high-efficiency flame retardancy, high-temperature resistance, and environmental adaptability a pressing issue for the industry. Utility Model Content

[0003] The purpose of this utility model is to provide a high flame-retardant and heat-resistant cable, which solves the problems of traditional cables in terms of flame retardant performance, service life and environmental adaptability, and meets the safe power transmission requirements under complex working conditions.

[0004] To achieve the above objectives, the present invention provides a high flame-retardant and heat-resistant cable, comprising a cable core and an outer sheath wrapped around the cable core. The cable core includes a plurality of wires and fillers, the fillers being filled in the gaps between the wires. The outer sheath has a multi-layer structure, the outermost layer of which is an expanded graphite coating.

[0005] Furthermore, the number of wire cores is 3, and the 3 wire cores are arranged in an equilateral triangle in the cable core.

[0006] Furthermore, the structure of the wire core includes: a conductor located at the center of the wire core, a fire-resistant layer wrapped around the outer surface of the conductor, an insulating layer wrapped around the outer surface of the fire-resistant layer, and a first expanded graphite coating located on the outer surface of the insulating layer.

[0007] Furthermore, the conductor is a type 2 annealed and compacted copper conductor, which is formed by twisting and compacting multiple strands of copper wire.

[0008] Furthermore, the refractory layer is composed of overlapping and wrapping synthetic mica tape; the insulating layer is a high-density polyethylene layer.

[0009] Furthermore, the filler is a high-temperature resistant flame-retardant PP filler.

[0010] Furthermore, the outer sheath has a 6-layer structure, consisting of, from the inside out: a first wrapping tape wrapped around the filled cable core, an isolation sleeve wrapped around the first wrapping tape, an armor wrapped around the isolation sleeve, a second wrapping tape wrapped around the armor, a sheath wrapped around the second wrapping tape, and a second expanded graphite coating on the surface of the sheath.

[0011] Furthermore, the first packing tape is a ceramicized fireproof and fire-resistant composite tape; the isolation sleeve is a halogen-free, low-smoke, flame-retardant thermoplastic polyolefin sheath.

[0012] Furthermore, the armor is a double-layered, gap-wrapped galvanized steel strip; the second wrapping strip is a low-smoke, halogen-free, high-flame-retardant strip.

[0013] Furthermore, the sheath is a halogen-free, low-smoke, flame-retardant thermoplastic polyolefin sheath.

[0014] In summary, the device structure of this utility model is reasonably designed, and the technical solution of this utility model has the following beneficial effects: This application provides an expanded graphite coating in the outermost layer of the cable. The expanded graphite coating is formed into a continuous and dense structure through a spraying process. When heated, the expanded graphite can rapidly expand to form a heat insulation layer, effectively blocking external flames and heat conduction. This coating acts directly on the outermost side of the cable, which can quickly isolate oxygen from flammable gases in the early stages of a fire, reducing the possibility of combustion and delaying the spread of fire. At the same time, the expanded graphite coating differs from the problem of easy breakage at the joints of traditional expanded graphite tape coatings. The sprayed coating is integrated with the surface of the outer sheath, eliminating the risk of wear and breakage caused by mechanical drag, ensuring that the flame-retardant performance of the cable is stable for more than 35 years of design life in harsh environments such as outdoor laying and underwater immersion, and avoiding protective failure due to environmental corrosion or installation damage. Attached Figure Description

[0015] Figure 1 This is a schematic cross-sectional view of the high flame-retardant and heat-resistant cable of this utility model. Explanation of reference numerals in the attached drawings: 1-Conductor; 2-Refractory layer; 3-Insulating layer; 4-First expanded graphite coating; 5-Filler; 6-First wrapping tape; 7-Insulating sleeve; 8-Armor; 9-Second wrapping tape; 10-Sheath; 11-Second expanded graphite coating. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model, but this does not constitute a limitation on the scope of protection of the present utility model.

[0017] In this utility model, for clearer description, the following explanation is provided: The observer faces the attached... Figure 1 When observing, the observer's left front side is designated as "front," the observer's right rear side as "rear," the observer's left rear side as "left," the observer's right front side as "right," the observer's top as "up," and the observer's bottom as "down." It should be noted that the terms "front end," "rear end," "left side," "right side," "middle," "above," and "below" in this text indicate orientations or positional relationships based on the accompanying drawings. These are merely for the purpose of clearly describing the present invention and do not indicate or imply that the structure or component referred to must have a specific orientation or be constructed in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," "third," and "fourth" are used only for the purpose of clarity or simplification of description and should not be construed as indicating or implying relative importance or quantity.

[0018] With societal development, people are increasingly prioritizing fire safety. In various locations, such as commercial buildings, residential houses, and industrial plants, fires can cause significant casualties and property damage. Cables, as crucial carriers of electricity and signals, are highly susceptible to ignition and the spread of flames in the event of a fire. Traditional cables can also generate large amounts of toxic fumes, hindering evacuation and firefighting efforts. Expanded graphite, however, possesses excellent flame-retardant properties. High-flame-retardant cables coated with expanded graphite rapidly expand to form a dense protective layer when exposed to high temperatures, effectively preventing the spread of flames, reducing fire hazards, and meeting the market's urgent need for fire safety.

[0019] In applications requiring high flame retardancy, such as hotels, banks, hospitals, factories, and integrated wiring in commercial and residential buildings, durable wires and cables with high flame retardancy are needed. Sprayed expanded graphite high flame retardant cables were developed to meet this need, effectively preventing the spread of fire in the event of a fire, protecting personnel and property, and reducing fire damage.

[0020] High flame-retardant cables coated with expanded graphite exhibit superior flame-retardant performance and high-temperature stability compared to ordinary high flame-retardant cables. Expanded graphite possesses excellent expansion characteristics, rapidly expanding at high temperatures to form a heat-insulating layer. When heated, expanded graphite rapidly expands, forming a fluffy heat-insulating layer. This layer effectively blocks heat transfer and isolates oxygen from contact with the cable's internal materials, achieving highly efficient flame retardancy. Furthermore, the rapid expansion process provides excellent protection even in the early stages of a fire.

[0021] The main features are as follows: 1. Good heat resistance Expanded graphite undergoes a chemical reaction at high temperatures, producing an expansion effect and forming a fluffy insulating layer. This insulating layer has excellent heat insulation properties, effectively preventing heat from being conducted into the cable, thus protecting the cable's internal insulation materials and conductors from high-temperature damage.

[0022] 2. Improve electrical conductivity Expanded graphite, as a conductive filler, can significantly improve the conductivity of polymer materials, enabling the polymer to transform from an insulator to a semiconductor. This helps optimize the overall electrical performance of cables.

[0023] 3. Enhance environmental adaptability The flexibility and resilience of expanded graphite enable it to maintain the stability and durability of cables under various environmental conditions.

[0024] 4. High flame retardancy Under high-temperature conditions, expanded graphite in sprayed cables can rapidly expand to form a heat insulation layer, preventing the spread of flames and heat, thereby protecting the internal structure of the cable from damage and improving the cable's safety performance.

[0025] See Figure 1 This utility model provides a high flame-retardant and heat-resistant cable, including a cable core and an outer sheath wrapped around the cable core. The cable core includes a plurality of wire cores and filler 5, which fills the gaps between the wire cores. The outer sheath has a multi-layer structure, with the outermost layer being an expanded graphite coating.

[0026] Expanded graphite is applied using a spray coating method: During the production process, expanded graphite is sprayed onto the cable surface using a graphite powder spraying device. After spraying, the cable passes through a surface cleaning mechanism to remove excess graphite and impurities, ensuring a clean and uniform coating and improving the adhesion of the graphite powder. The cable then passes through a grinding mechanism to polish the coating, making it smoother and more even, improving the quality of the coating and ensuring it integrates seamlessly with the sheath surface.

[0027] During use, cables are susceptible to wear and corrosion on the surface of the sheath 10 due to long-term exposure to mechanical, chemical, and other external factors, thus affecting the cable's safety and service life. Expanded graphite, in addition to being fire-resistant and heat-resistant, also reduces friction and improves the coating's wear resistance. Spraying expanded graphite effectively enhances the durability of the sheath 10 and extends the cable's service life.

[0028] Specifically, there are 3 wire cores, which are arranged in an equilateral triangle in the cable core.

[0029] Specifically, the structure of the wire core includes: a conductor 1 located at the center of the wire core, a fire-resistant layer 2 wrapped around the outer surface of the conductor 1, an insulating layer 3 wrapped around the outer surface of the fire-resistant layer 2, and a first expanded graphite coating 4 located on the outer surface of the insulating layer 3.

[0030] Specifically, conductor 1 is a type 2 annealed and compacted copper conductor, which is made of multiple strands of copper wire twisted and compacted.

[0031] Specifically, the fire-resistant layer 2 is composed of overlapping synthetic mica tape; the insulation layer 3 is a high-density polyethylene layer.

[0032] Specifically, filler 5 is a high-temperature resistant flame-retardant PP filler.

[0033] In a preferred embodiment of this utility model, the outer sheath has a 6-layer structure, which consists of the following layers from the inside out: a first wrapping tape 6 wrapped around the filled cable core, an isolation sleeve 7 wrapped around the first wrapping tape 6, an armor 8 wrapped around the isolation sleeve 7, a second wrapping tape 9 wrapped around the armor 8, a sheath 10 wrapped around the second wrapping tape 9, and a second expanded graphite coating 11 on the surface of the sheath 10.

[0034] Specifically, the first packing tape 6 is a ceramicized fireproof and fire-resistant composite tape; the isolation sleeve 7 is a halogen-free, low-smoke, flame-retardant thermoplastic polyolefin sheath 10.

[0035] Specifically, the armor 8 is a double-layered, gap-wrapped galvanized steel strip; the second wrapping strip 9 is a low-smoke, halogen-free, high-flame-retardant strip.

[0036] Specifically, the sheath 10 is a halogen-free, low-smoke, flame-retardant thermoplastic polyolefin sheath 10.

[0037] The main features of each layer of this utility model are as follows: 1. The conductor is a Class 2 annealed compacted copper conductor, which is made of multiple strands of copper wire twisted and compacted. The compacted copper conductor has excellent conductivity, mechanical strength and production efficiency, which not only improves the efficiency and safety of power transmission, but also reduces the cost of long-term operation.

[0038] 2. The fire-resistant layer is made of overlapping synthetic mica tape, which has a high heat resistance level and unique fire-resistant properties. It can reach the Class A fire resistance level and can maintain normal operation for more than 1.5 hours under flame conditions of 950-1000℃.

[0039] 3. The insulation layer is made of high-density polyethylene (HDPE). HDPE has high strength and toughness, and can withstand large mechanical stress. It has excellent electrical properties, especially high dielectric strength, and as an insulation material for wires and cables, it can effectively protect wires and cables from external environmental corrosion.

[0040] 4. The first expanded graphite coating involves uniformly spraying a layer of expanded graphite onto the surface of the insulation layer. Expanded graphite serves as a coating material, improving the high-temperature resistance and sealing performance of the insulation layer. Expanded graphite possesses excellent thermal conductivity and thermal expansion properties, exhibiting rapid expansion upon heating or at high temperatures. Under high-temperature conditions, expanded graphite can rapidly expand to form a heat insulation layer, preventing the propagation of flames and heat, thereby protecting the internal structure of the cable from damage and improving its safety performance.

[0041] 5. The filler is made of high-temperature resistant flame-retardant PP filler. High-temperature resistant flame-retardant PP filler can increase the flexibility of the cable, making it less prone to breakage when bending and folding, thereby extending the service life of the cable. High-temperature resistant flame-retardant PP filler can also increase the mechanical strength of the cable, making it better able to withstand external pressure and tension.

[0042] 6. The first layer of tape is a ceramic fireproof and fire-resistant composite tape. When the cable is made, the ceramic fireproof and fire-resistant composite tape is used for overlapping wrapping. At a temperature of 590℃~2950℃, the ceramic fireproof and fire-resistant composite tape is quickly burned into a hard and complete ceramic shell. The hard shell armor after burning provides good protection for the line and ensures the line can continue to operate normally in the event of a fire.

[0043] 7. The isolation sleeve is made of flame-retardant thermoplastic polyolefin sheath material, which effectively protects the cable core from damage by the armor metal.

[0044] 8. Armor: The cable is armored with steel tape, using double-layer gap wrapping with galvanized steel tape, which increases the mechanical strength of the cable, improves its corrosion resistance, increases its tensile and compressive strength, and extends its service life through mechanical protection.

[0045] 9. The second wrapping tape uses low-smoke halogen-free high flame-retardant tape for overlapping wrapping. By overlapping wrapping, it can be ensured that every part of the cable is covered by flame-retardant tape, avoiding protective gaps, thereby improving the overall flame-retardant performance and safety of the cable, and effectively playing a flame-retardant role.

[0046] 10. The sheath is made of halogen-free, low-smoke, flame-retardant thermoplastic polyolefin material. The sheath material has excellent flame-retardant effect and has the advantages of good self-extinguishing properties, low smoke release, low toxicity, and rodent and ant prevention.

[0047] 11. The second expanded graphite coating, a layer of expanded graphite uniformly sprayed onto the surface of the sheath, further enhances the flame-retardant properties of the sheath. The expansion and insulating effect of expanded graphite at high temperatures provides additional protection for the polyolefin sheath, reduces the contact between combustible gases and oxygen, lowers the possibility of combustion and the speed of fire spread, and enables the sheath to better protect the internal structure of the cable in the event of a fire, thereby improving the safety performance of the cable.

[0048] In this invention, expanded graphite is applied using a spraying method. During production, expanded graphite is sprayed onto the cable surface using a graphite powder spraying device. After spraying, the cable passes through a surface cleaning mechanism to remove excess graphite and impurities, ensuring a clean and uniform coating and improving the adhesion of the graphite powder. The cable then passes through a grinding mechanism to polish the coating, making it smoother and more even, improving the quality of the coating and ensuring it integrates seamlessly with the sheath surface.

[0049] During use, cables are susceptible to wear and corrosion on the sheath surface due to long-term exposure to external factors such as mechanical and chemical agents, which affects the cable's safety and service life. Expanded graphite can reduce friction and improve the wear resistance of the coating. Spraying expanded graphite can effectively improve the durability of the sheath and extend the cable's service life.

[0050] Expanded graphite coating process for cable surfaces: 1. Preparation stage: Ensure the cable surface is clean and dust-free so that the expanded graphite can adhere firmly.

[0051] 2. Spraying process: Use specialized spraying equipment to evenly spray expanded graphite onto the cable surface. The spraying thickness should be determined according to design requirements and fire protection standards, generally between 0.1 and 0.5 mm.

[0052] 3. Drying and curing: After spraying, allow the expanded graphite layer to dry naturally or accelerate drying at a suitable temperature to ensure that the coating is completely cured.

[0053] 4. Quality Inspection: After drying and curing, the expanded graphite coating on the cable surface should be inspected to ensure that the coating is intact and free from obvious defects or peeling.

[0054] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications are also considered to be within the protection scope of this utility model.

Claims

1. A high flame-retardant and heat-resistant cable, comprising a cable core and an outer sheath wrapped around the cable core, characterized in that: The cable core includes several wire cores and filler material, the filler material filling the gaps between the wire cores; the outer sheath has a multi-layer structure, the outermost layer of which is an expanded graphite coating; the number of wire cores is 3, the 3 wire cores are arranged in an equilateral triangle in the cable core; the structure of the wire core includes: a conductor located at the center of the wire core, a fire-resistant layer wrapped around the outer surface of the conductor, an insulation layer wrapped around the outer surface of the fire-resistant layer, and a first expanded graphite coating located on the outer surface of the insulation layer; the fire-resistant layer is composed of overlapping synthetic mica tape; the insulation layer is... The outer sheath consists of a high-density polyethylene layer and a six-layer structure, from the inside out: a first wrapping tape wrapped around the filled cable core, an isolation sleeve wrapped around the first wrapping tape, armor wrapped around the isolation sleeve, a second wrapping tape wrapped around the armor, a sheath wrapped around the second wrapping tape, and a second expanded graphite coating on the surface of the sheath; the first wrapping tape is a ceramicized fire-resistant composite tape; the isolation sleeve is a halogen-free, low-smoke, flame-retardant thermoplastic polyolefin sheath; the armor is a double-layer, gap-wrapped galvanized steel tape; and the second wrapping tape is a low-smoke, halogen-free, high-flame-retardant tape.

2. The high flame-retardant and heat-resistant cable according to claim 1, characterized in that: The conductor is a type 2 annealed and compacted copper conductor, which is made of multiple strands of copper wire twisted and compacted together.

3. The high flame-retardant and heat-resistant cable according to claim 2, characterized in that: The filler is a high-temperature resistant flame-retardant PP filler.

4. The high flame-retardant and heat-resistant cable according to claim 3, characterized in that: The sheath is a halogen-free, low-smoke, flame-retardant thermoplastic polyolefin sheath.

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