Fire resistant cable

Abstract

The utility model discloses a kind of fire-resistant cable, including copper conductor, fire resistance layer, insulating layer, fire barrier, gasket layer and sheath layer;The outside of copper conductor is equipped with fire resistance layer, the outside of fire resistance layer is equipped with insulating layer, the outside of insulating layer is equipped with fire barrier, the outside of fire barrier is equipped with gasket layer, the outside of gasket layer is equipped with sheath layer.Fire barrier is arranged at the outside of insulating layer, can intercept heat earlier, reduce core structure to be attacked by high temperature;Multi-core cable edge area is filled by fire barrier material actively, cooperate center fiber filling and form dead corner seal, block flame penetration path;Gasket layer is coated with fire barrier, construct the structure of inner seal and outer support combination, improve impact resistance under high temperature;Fire resistance layer and insulating layer form composite insulation, enhance electrical stability under extreme environment;Further effectively avoid the problem of insulation failure, conductor fuse and power interruption in fire.

Description

Technical Field

[0001] This utility model belongs to the field of fire-resistant cable technology, specifically relating to a fire-resistant cable. Background Technology

[0002] With the increasing frequency of various fire accidents and the growing severity of loss of life and property, the performance requirements of fire-resistant cables in fire protection systems have shifted from meeting basic testing standards to adapting to extreme scenarios of real fires. As the lifeline for power transmission in critical locations such as buildings, shopping malls, subways, airports, and petrochemical and metallurgical industries, the reliability of fire-resistant cables directly determines the lighting of personnel evacuation routes, the operation of fire-fighting equipment, and the smooth operation of rescue command systems during a fire. Their stability under high temperature, high pressure, and complex working conditions is of paramount importance. Currently, the technical bottlenecks of fire-resistant cables are becoming increasingly prominent: existing test methods are significantly out of sync with real fire scenarios. In tests, cables are mostly laid out horizontally as single strands, while in actual projects they are often laid in bundles. Tests use a single torch at 750°C for 90 minutes of localized burning as the standard, while in real fires, cables are often completely encased in flames exceeding 1000°C for several hours. The test environment temperature is consistently low, while in real fires, the ambient temperature rises continuously with the fire, exceeding 1000°C within 180 minutes, accompanied by external impacts such as vibration and water spray. These differences directly lead to numerous fatal flaws in existing fire-resistant cables during actual fires: the gap filling in multi-core cables relies on static materials, which are prone to shrinkage or ablation at high temperatures, creating channels for flames and high-temperature gases to penetrate, resulting in "gap fire"; the fire-resistant layer often uses rigid materials and is positioned too far outward, making it difficult to adaptively seal irregular gaps, and heat must penetrate multiple layers of the structure to be blocked, causing the core insulation layer and conductor to fail prematurely due to high-temperature attack; in some designs, the barrier formed by high-temperature sintering is not dense enough to withstand prolonged high-temperature impacts and external mechanical interference, easily leading to structural collapse. These problems often cause existing fire-resistant cables to interrupt power supply during critical stages of a fire due to insulation failure and conductor melting, posing serious safety risks. Utility Model Content

[0003] To address the aforementioned problems, this utility model provides a fire-resistant cable. A fire-resistant layer is positioned outside the insulation layer, intercepting heat earlier and reducing the impact of high temperatures on the core structure. The edge areas of the multi-core cable are actively filled with the fire-resistant layer material, forming a seamless seal with the central fiber filling, blocking the path of flame penetration. A fire-resistant layer covers the outer layer of the liner, creating a structure combining internal sealing and external support, improving impact resistance at high temperatures. The fire-resistant layer and the insulation layer form composite insulation, enhancing electrical stability under extreme environments. This effectively prevents power outages due to insulation failure and conductor melting during a fire.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A fire-resistant cable includes a copper conductor, a fire-resistant layer, an insulation layer, a fire-resistant layer, a padding layer, and a sheath layer; the fire-resistant layer is sleeved on the outside of the copper conductor, the insulation layer is sleeved on the outside of the fire-resistant layer, the fire-resistant layer is sleeved on the outside of the insulation layer, the padding layer is sleeved on the outside of the fire-resistant layer, and the sheath layer is sleeved on the outside of the padding layer; the fire-resistant layer is composed of inorganic mineral insulating tape, the fire-resistant layer is composed of ceramicized silica gel mud extrusion, and the padding layer is composed of ceramicized fire-resistant composite tape.

[0005] As a further technical solution, the insulation layer is made of ceramicized polyolefin extrusion.

[0006] As a further technical solution, the sheath layer is formed by extrusion of halogen-free, low-smoke, flame-retardant polyolefin sheath material.

[0007] As a further technical solution, the inorganic mineral insulating tape is a composite structure of one or more of the following: synthetic mica tape, calcined mica tape, and coated mica tape.

[0008] A fire-resistant cable includes a copper conductor, a fire-resistant layer, an insulation layer, a fire-resistant layer, a padding layer, a sheath layer, and a central filler. Several copper conductors are provided, with a fire-resistant layer covering the outside of the copper conductors and a fire-resistant layer covering the outside of the insulation layer. The copper conductors, the fire-resistant layer, and the insulation layer form a wire core, and a central filler is provided on the inside of the wire core.

[0009] As a further technical solution, the central filler is an inorganic fiber, which fills the inner side of the insulation layer of the core.

[0010] As a further technical solution, the inner surfaces of the insulation layer and the fireproof layer are tightly attached.

[0011] As a further technical solution, a padding layer is fitted on the outside of the fire-resistant layer, and the outer surface of the fire-resistant layer and the inner surface of the padding layer are in close contact.

[0012] As a further technical solution, a sheath layer is fitted over the outer side of the padding layer, with the outer surface of the padding layer and the inner surface of the sheath layer in close contact.

[0013] As a further technical solution, the refractory layer is composed of inorganic mineral insulating tape wrapped around it, the insulating layer is composed of ceramicized polyolefin extrusion, the fireproof layer is composed of ceramicized silica gel mud extrusion, the padding layer is composed of ceramicized refractory composite tape wrapped around it, and the sheath layer is composed of halogen-free low-smoke flame-retardant polyolefin sheath material extrusion; the inorganic mineral insulating tape is a composite structure of one or more of synthetic mica tape, calcined mica tape, and coated mica tape.

[0014] Compared with the prior art, the advantages and positive effects of this utility model are: The fire-resistant layer of this invention is located outside the insulation layer and inside the padding layer, bringing it closer to the conductor and insulation layer, thus blocking heat conduction in advance. In the early stages of a fire, flames and heat first pass through the sheath and padding layers, where they are quickly intercepted by the inwardly positioned fire-resistant layer. Furthermore, the fire-resistant layer is constructed from ceramicized silica gel mortar extruded into a viscous state at 350-600℃, tightly adhering to the surface of the insulation layer. Above 600℃, it further forms a dense silicate ceramic layer, directly creating a heat insulation barrier on the outside of the insulation layer. This reduces heat transfer to the insulation layer and conductor, preventing premature aging or failure of the core structure due to high temperatures, achieving insulation earlier, and extending the durability of the insulation layer and conductor.

[0015] In this invention, the multi-core cable is filled only with inorganic fibers in the central area, while the edge areas are actively filled during the extrusion of the fire-resistant layer. In the single-core cable, the fire-resistant layer directly and tightly covers the insulation layer. The ceramicized silica paste, with its high-temperature fluidity, can adaptively fill irregular spaces such as the edge areas and interlayer gaps of the multi-core cable. After curing, it forms a continuous, non-porous ceramic layer, completely blocking the path of flames and high-temperature gases through the gaps. This avoids the risk of fire spread and ensures the integrity of the overall protection of the core.

[0016] This invention features a liner layer wrapped around the outside of the fire-resistant layer, forming a combination of a soft inner layer and a hard outer layer. During a fire, the fire-resistant layer first seals the gaps through fluidity, then solidifies to form a hard ceramic layer. The outer liner layer is sintered at temperatures above 500℃ to form a ceramic-like structure, providing mechanical support to the fire-resistant layer and resisting external impacts such as vibrations and water spray during a fire. This structure makes the fire-resistant layer less prone to cracking or detachment due to external disturbances, ensuring the integrity of the heat insulation barrier at high temperatures.

[0017] This invention features a double insulation system: a fire-resistant layer is first wrapped around the conductor, followed by an extruded insulation layer. The fire-resistant layer maintains excellent insulation properties at 1200℃, while the insulation layer is sintered into a ceramic-like shell above 600℃. Together, they form a composite insulation system. Even if the fire-resistant layer and the liner layer are partially damaged, the composite insulation layer can still prevent short circuits in the conductor, ensuring uninterrupted power transmission and improving the electrical reliability of the cable under extreme high temperatures. Attached Figure Description

[0018] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0019] Figure 1 This is a schematic diagram of the single-core structure of the fire-resistant cable of this utility model; Figure 2 This is a schematic diagram of the multi-core structure of the fire-resistant cable of this utility model; In the diagram: 1-Copper conductor; 2-Fire-resistant layer; 3-Insulation layer; 4-Central filler; 5-Fireproof layer; 6-Padding layer; 7-Sheath layer. Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0020] These differences directly lead to numerous fatal flaws in existing fire-resistant cables during actual fires: the gap filling in multi-core cables relies on static materials, which are prone to shrinkage or ablation at high temperatures, creating channels for flames and high-temperature gases to penetrate, resulting in "gap fire"; the fire-resistant layer often uses rigid materials and is positioned too far outward, making it difficult to adaptively seal irregular gaps, and heat must penetrate multiple layers of the structure to be blocked, causing the core insulation layer and conductor to fail prematurely due to high-temperature attack; in some designs, the barrier formed by high-temperature sintering is not dense enough to withstand prolonged high-temperature impacts and external mechanical interference, easily leading to structural collapse. These problems often cause existing fire-resistant cables to interrupt power supply during critical stages of a fire due to insulation failure and conductor melting, posing serious safety risks.

[0021] Example 1: The present invention will now be described in detail with reference to the accompanying drawings. This embodiment discloses a fire-resistant cable, such as... Figure 1 As shown, it includes a copper conductor 1, a fire-resistant layer 2, an insulating layer 3, a fire-resistant layer 5, a padding layer 6, and a sheath layer 7; the copper conductor 1 is covered with a fire-resistant layer 2, the fire-resistant layer 2 is covered with an insulating layer 3, the insulating layer 3 is covered with a fire-resistant layer 5, the fire-resistant layer 5 is covered with a padding layer 6, and the padding layer 6 is covered with a sheath layer 7; the fire-resistant layer 2 is made of inorganic mineral insulating tape, the fire-resistant layer 5 is made of ceramicized silica gel mud, and the padding layer 6 is made of ceramicized fire-resistant composite tape.

[0022] Specifically, the fire-resistant layer 5 is located outside the insulation layer 3 and inside the padding layer 6, bringing the fire-resistant layer 5 closer to the area between the conductor and the insulation layer 3, thus blocking heat conduction in advance. In the early stages of a fire, flames and heat first pass through the sheath layer 7 and the padding layer 6, and can be quickly intercepted by the inwardly moved fire-resistant layer 5.

[0023] Furthermore, the fireproof layer 5 is composed of ceramicized silica paste extruded from the ceramicized silica paste. The ceramicized silica paste melts at 350-600℃ to form a viscous flow state, which closely adheres to the surface of the insulation layer 3. Above 600℃, a dense silicate ceramic layer is further generated, which directly forms a heat insulation barrier on the outside of the insulation layer 3, reducing the transfer of heat to the insulation layer 3 and the conductor, preventing the core structure from aging or failing prematurely due to high temperature, achieving heat insulation earlier, and extending the withstand time of the insulation layer 3 and the conductor.

[0024] The liner layer 6 wraps around the outside of the fire-resistant layer 5, forming a combination of a soft inner layer and a hard outer layer. During a fire, the fire-resistant layer 5 first seals the gaps through fluidity, and then solidifies to form a hard ceramic layer; the outer liner layer 6 is sintered into a ceramic-like body at temperatures above 500℃, providing mechanical support for the fire-resistant layer 5 and resisting external impacts such as vibration and water spray during a fire. This structure makes the fire-resistant layer 5 less prone to cracking or falling off due to external interference, ensuring the integrity of the heat insulation barrier at high temperatures.

[0025] This invention first wraps a fire-resistant layer 2 around the conductor, then extrudes an insulating layer 3, forming double insulation. The fire-resistant layer 2 maintains excellent insulation at 1200℃, while the insulating layer 3 is sintered into a ceramic-like shell at temperatures above 600℃. Together, they form a composite insulation system. Even if the fire-resistant layer 5 and the padding layer 6 are partially damaged, the composite insulating layer 3 can still prevent short circuits in the conductor, ensuring uninterrupted power transmission and improving the electrical reliability of the cable under extreme high temperatures.

[0026] Insulation layer 3 is made of ceramicized polyolefin extrusion. Sheath layer 7 is made of halogen-free, low-smoke, flame-retardant polyolefin sheath material extrusion. The inorganic mineral insulation tape is a composite structure of one or more of synthetic mica tape, calcined mica tape, and coated mica tape.

[0027] The cable employs a fire-resistant and heat-insulating structural design. Insulation layer 3 is made of ceramicized polyolefin material, fire-resistant layer 5 is made of ceramicized silica gel putty material, and the lining layer 6 is made of ceramicized fire-resistant composite tape. These three materials sinter into a ceramic-like shell after flame ablation, preventing the spread of flames and heat into the cable's interior and protecting the internal structure. The combination of insulation layer 3 and fire-resistant layer 2 improves the cable's electrical insulation performance under flame conditions. Extensive use of flame-retardant materials enhances the cable's flame-retardant properties. In external fires, the cable does not spontaneously combust or support combustion, reducing fire intensity and smoke, and minimizing personal injury.

[0028] Because fire-resistant layer 2 uses inorganic mineral insulation tape and insulation layer 3 uses extruded ceramicized polyolefin material, fire-resistant layer 2 and insulation layer 3 constitute composite insulation, and both are fire-resistant and high-temperature resistant materials, maintaining high insulation performance under flame and high-temperature conditions. Fire-resistant layer 5 uses extruded ceramicized silica gel putty material, padding layer 6 uses ceramicized fire-resistant composite tape, and sheath layer 7 uses halogen-free, low-smoke, flame-retardant polyolefin material with good shelling performance. Ceramicized polyolefin material, ceramicized silica gel putty material, and ceramicized fire-resistant composite tape have excellent high-temperature resistance. When subjected to heat and flame erosion, a hard ceramic layer is formed on the surface, isolating flame and heat from being transferred to the inside of the cable, thus playing a role in fire and heat insulation. The fire-resistant and heat-insulating structural design of insulation layer 3, fire-resistant layer 5, and padding layer 6 ensures that the cable can operate continuously and stably in a fire environment with continuously rising temperatures, buying time for rescue and escape.

[0029] Example 2: A type of fire-resistant cable, such as Figure 2 As shown, the conductor includes a copper conductor 1, a fire-resistant layer 2, an insulation layer 3, a fire-resistant layer 5, a padding layer 6, a sheath layer 7, and a central filler 4. Several copper conductors 1 are provided. The fire-resistant layer 2 is fitted over the outer side of each copper conductor 1, and the fire-resistant layer 5 is fitted over the outer side of each insulation layer 3. The copper conductors 1, fire-resistant layer 2, and insulation layer 3 form the wire core. The central filler 4 is located inside the wire core. The central filler 4 is made of inorganic fiber and fills the inner side of the insulation layer 3 of the wire core.

[0030] Specifically, in multi-core cables, only the central area is filled with inorganic fibers, while the edge areas are actively filled during the extrusion of the fire-resistant layer 5. The ceramicized silica paste, with its high-temperature fluidity, can adaptively fill irregular spaces such as the edge areas and interlayer gaps of the multi-core cable. After curing, it forms a continuous, non-porous ceramic layer, completely blocking the path of flames and high-temperature gases through the gaps. This avoids the risk of fire spread and ensures the integrity of the overall protection for the cores.

[0031] Specifically, the wire core consists of a copper conductor 1, a fire-resistant layer 2, and an insulation layer 3. The wire core adopts a concentric stacked structure, with the copper conductor, fire-resistant layer, and insulation layer arranged from the inside out: the innermost layer is the copper conductor, the fire-resistant layer 2 is tightly wrapped around the outside of the copper conductor 1 and fixed by wrapping or longitudinal wrapping processes, and the insulation layer 3 completely covers the outside of the fire-resistant layer 2 and is formed by extrusion processes to form a uniform insulation layer 3.

[0032] Specifically, this embodiment has 5 insulated wire cores, each consisting of a copper conductor 1, a fire-resistant layer 2 covering the copper conductor 1, and an insulating layer 3 extruded onto the fire-resistant layer 2. The copper conductor 1 is made of multiple strands of fine copper wire twisted together. The copper conductor 1, the fire-resistant layer 2, and the insulating layer 3 together constitute the insulated wire core, which is twisted together to form a wire core. Inorganic fibers are filled in the central area between the insulated wire cores, while the edge areas are not filled. A ceramicized silica gel mud is extruded over the wire core to form a fire-resistant layer 5, which fills the edge areas of the wire core. A ceramicized fire-resistant composite tape is wrapped around the fire-resistant layer 5 to form a padding layer 6. The outermost layer is a sheath layer 7, which is an extruded halogen-free, low-smoke, flame-retardant polyolefin.

[0033] The inner surfaces of the insulating layer 3 and the fireproof layer 5 are in close contact. A padding layer 6 is fitted over the outside of the fireproof layer 5, and the outer surface of the fireproof layer 5 and the inner surface of the padding layer 6 are in close contact. A sheath layer 7 is fitted over the outside of the padding layer 6, and the outer surface of the padding layer 6 and the inner surface of the sheath layer 7 are in close contact.

[0034] The refractory layer 2 is composed of inorganic mineral insulating tape wrapped around it; the insulating layer 3 is composed of ceramicized polyolefin extrusion; the fire-resistant layer 5 is composed of ceramicized silica gel mortar extrusion; the padding layer 6 is composed of ceramicized refractory composite tape wrapped around it; and the sheath layer 7 is composed of halogen-free, low-smoke, flame-retardant polyolefin sheath material extrusion. The inorganic mineral insulating tape is a composite structure of one or more of synthetic mica tape, calcined mica tape, and coated mica tape.

[0035] Specifically, fire-resistant layer 2 is an inorganic mineral insulation tape, serving as the core fire-resistant barrier for the cable. Utilizing the high-temperature resistance of mica, it maintains insulation performance under extreme conditions, preventing direct flame erosion of the conductor. Insulation layer 3 is a ceramicized polyolefin, providing electrical insulation under normal conditions and transforming into a ceramic shell during a fire. This maintains insulation while providing physical support for the inner structure, resisting flame impact. Fire-resistant layer 5 is a ceramicized silica gel mortar, which is extruded to fill cable gaps and solidifies into a dense fire-resistant barrier at high temperatures, blocking the penetration path of flames and heat and reducing the baking of inner materials. Liner layer 6 is a ceramicized fire-resistant composite tape, wrapped around the outside of fire-resistant layer 5, enhancing the overall structure's tensile and deformation resistance while also assisting in heat insulation and protecting the outer sheath. Sheath layer 7 is a halogen-free, low-smoke, flame-retardant polyolefin sheath, serving as the outermost layer of protection. Under normal conditions, it resists mechanical damage and environmental corrosion; during a fire, it slows the spread of combustion, reduces toxic fumes, and improves the safety of personnel evacuation.

[0036] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. A fire-resistant cable, characterized in that, It includes a copper conductor, a refractory layer, an insulating layer, a fire-resistant layer, a padding layer, and a sheath layer; the copper conductor is covered with a refractory layer, the refractory layer is covered with an insulating layer, the insulating layer is covered with a fire-resistant layer, the fire-resistant layer is covered with a padding layer, and the padding layer is covered with a sheath layer; the refractory layer is composed of inorganic mineral insulating tape wrapped around it, the fire-resistant layer is composed of ceramicized silica gel mud extruded around it, and the padding layer is composed of ceramicized refractory composite tape wrapped around it.

2. The fire-resistant cable as described in claim 1, characterized in that, The insulating layer is formed by extrusion of ceramicized polyolefin.

3. The fire-resistant cable as described in claim 1, characterized in that, The sheath layer is formed by extrusion of halogen-free, low-smoke, flame-retardant polyolefin sheath material.

4. A fire-resistant cable as described in claim 1, characterized in that, The inorganic mineral insulating tape is a composite structure of one or more of the following: synthetic mica tape, calcined mica tape, and coated mica tape.

5. A fire-resistant cable, characterized in that, It includes a copper conductor, a fire-resistant layer, an insulating layer, a fire-resistant layer, a padding layer, a sheath layer, and a central filler; several copper conductors are provided, a fire-resistant layer is sleeved on the outside of the copper conductors, a fire-resistant layer is sleeved on the outside of the insulating layer, and a wire core is formed by the copper conductors, the fire-resistant layer, and the insulating layer, with a central filler provided on the inside of the wire core.

6. A fire-resistant cable as described in claim 5, characterized in that, The central filler is an inorganic fiber, and the central filler fills the inner side of the insulation layer of the wire core.

7. A fire-resistant cable as described in claim 5, characterized in that, The inner surfaces of the insulating layer and the fireproof layer are in close contact.

8. A fire-resistant cable as described in claim 5, characterized in that, A padding layer is fitted on the outside of the fireproof layer, and the outer surface of the fireproof layer and the inner surface of the padding layer are in close contact.

9. A fire-resistant cable as described in claim 5, characterized in that, A protective sleeve is fitted over the outer side of the padding layer, and the outer surface of the padding layer and the inner surface of the protective sleeve are in close contact.

10. A fire-resistant cable as described in claim 5, characterized in that, The refractory layer is composed of inorganic mineral insulating tape wrapped around it, the insulating layer is composed of ceramicized polyolefin extrusion, the fireproof layer is composed of ceramicized silica gel mud extrusion, the padding layer is composed of ceramicized refractory composite tape wrapped around it, and the sheath layer is composed of halogen-free low-smoke flame-retardant polyolefin sheath material extrusion; the inorganic mineral insulating tape is a composite structure of one or more of synthetic mica tape, calcined mica tape, and coated mica tape.

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