High-flame-retardant fireproof power cable

Abstract

The utility model relates to the technical field of cables, and provides a high-flame-retardant fireproof power cable, which comprises a plurality of cable cores, a filling layer is arranged among the cable cores, a protective layer and a sheath are sequentially arranged outside the filling layer from inside to outside, and each cable core comprises a conductor, a fireproof layer and an insulating layer which are sequentially arranged from inside to outside. According to the utility model, the internal temperature resistance and flame retardant performance of the cable are greatly improved, the conductors are effectively protected, the safety of the cable in a use place and the continuous power supply time when a fire disaster occurs are improved, so that emergency measures can be taken for rescue, and the safety of the cable is improved. Therefore, personal and property safety is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of cables, in particular to a highly flame-retardant and fire-resistant power cable. Background Art

[0002] Low-voltage cables are the most common power cables in daily life. They are responsible for the transmission and distribution of power resources and are essential to daily life. However, unsafe power cables are also one of the ways for fires to spread, so their flame retardant and fire-resistant properties are particularly critical.

[0003] In the prior art, measures to improve the flame retardancy of power cables are mostly achieved through flame retardant materials. For example, in the patent document with publication number "CN116779237A", the cable includes a copper core conductor, a fire-resistant layer, an insulating layer, a flame retardant filling layer, a wrapping tape layer, an oxygen-insulating layer and a sheath from the inside to the outside, wherein the flame retardant filling layer is twisted into a cable by twisting an insulating core and a low-smoke halogen-free PP filling rope, the wrapping tape layer is wrapped tightly with a low-smoke halogen-free flame-retardant tie, the oxygen-insulating layer is made of environmentally friendly low-smoke halogen-free flame-retardant material by extrusion drawing, and the sheath is made of a highly flame-retardant, low-smoke, halogen-free polyolefin composite, which can have a flame retardant effect to a certain extent. However, in actual applications, the sheath made of the highly flame-retardant, low-smoke, halogen-free polyolefin composite mainly plays a role, the flame retardant effect of the inner layer is limited, and the flame retardant and fire-resistant effects still need to be improved. Utility Model Content

[0004] The utility model aims to provide a highly flame-retardant and fire-resistant power cable to solve the above-mentioned defects of the prior art.

[0005] The embodiments of the present invention are implemented by the following technical solutions:

[0006] A highly flame-retardant and fire-resistant power cable comprises a plurality of cable cores, a filling layer is arranged between the plurality of cable cores, a protective layer and a sheath are arranged outside the filling layer in sequence from the inside to the outside, the cable core comprises a conductor, a fire-resistant layer and an insulating layer arranged in sequence from the inside to the outside, and the insulating layer comprises a radiation cross-linked polyethylene layer and a radiation cross-linked polyolefin layer arranged in sequence from the inside to the outside.

[0007] Optionally, the protective layer includes, from inside to outside, a first wrapping tape layer, an oxygen barrier layer and a second wrapping tape layer.

[0008] Optionally, the first wrapping tape layer and the second wrapping tape layer are both formed by bundling two layers of halogen-free oxygen-isolating tapes.

[0009] Optionally, the oxygen barrier layer is B1 grade ceramic halogen-free low-smoke polyolefin.

[0010] Optionally, the sheath is B1 grade halogen-free low-smoke polyolefin.

[0011] Optionally, the filling layer is inorganic paper rope.

[0012] Optionally, the fire-resistant layer is a double-layer mica tape.

[0013] Optionally, an armor layer or a metal shielding layer is provided outside the sheath.

[0014] The technical solution of the present utility model has at least the following advantages and beneficial effects: in the present utility model, the insulating layer outside the conductor includes a radiation cross-linked polyethylene layer and a radiation cross-linked polyolefin layer arranged in sequence from the inside to the outside, the inner layer has excellent electrical properties and mechanical properties, and temperature resistance grade, and the outer layer has halogen-free, low-smoke, and flame-retardant properties, which greatly improves the temperature resistance and flame-retardant properties of the cable inside, effectively protects the conductor, improves the safety of the cable in the place of use and the continuous power supply time when a fire occurs, so as to facilitate the adoption of emergency measures for rescue, thereby ensuring the safety of people and property. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A schematic diagram of the structure of a highly flame-retardant and fire-resistant power cable provided by the utility model;

[0017] Icon: 1-conductor, 2-fire-resistant layer, 3-irradiation cross-linked polyethylene layer, 4-irradiation cross-linked polyolefin layer, 5-filling layer, 6-first wrapping tape layer, 7-oxygen insulation layer, 8-second wrapping tape layer, 9-sheath. DETAILED DESCRIPTION

[0018] Embodiment 1

[0019] refer to Figure 1 A highly flame-retardant and fire-resistant power cable comprises a plurality of cable cores, a filling layer 5 is arranged between the cable cores, a protective layer and a sheath 9 are arranged from the inside to the outside outside the filling layer 5, and the cable core comprises a conductor 1, a fire-resistant layer 2 and an insulating layer arranged from the inside to the outside.

[0020] The conductor 1 is selected to be a class 1, 2 or 5 conductor 1 in accordance with the GB / T3956-2008 standard, and can be designed with a T-shaped twisted structure. The conductor 1 has a compression coefficient of more than 0.95. When the copper rod with a resistivity of less than 0.017Ω·mm2 / m is used for processing, compared with the compressed round conductor 1 of the same cross-section, it has a small outer diameter, excellent conductivity, and a smooth and round surface. Taking the 70mm2 three-core 0.6 / 1kV cable structure as an example, the outer diameter of the T-shaped conductor 1 is 9.3mm, and the outer diameter of the finished cable is 32.5mm. The outer diameter of the compressed round conductor 1 is 10.0mm, and the outer diameter of the finished cable is 34mm. The outer diameter of the conductor 1 is 7% smaller, and the outer diameter of the finished cable is 4.4% smaller. The materials used in the overall cable can be saved by more than 1%.

[0021] The conductor 1 is wrapped with two layers of mica tape as the fire-resistant layer 2. In actual application, according to the fire resistance performance of GB / T19666-2019 and the fire resistance performance level and technical requirements of GA306.2-2007 (fire supply temperature 950℃~1000℃, 90min fire supply + 15min cooling, test voltage rated voltage, according to the test method of GB / T19216.21, the line integrity meets the 2A fuse and the indicator light is not extinguished, the smoke toxicity meets the ZA2 level in GB / T20285, the smoke density ≥80%, the corrosion resistance PH value ≥4.3, the conductivity ≤10μs / mm), according to GB / T19216 or I EC60331 test method, test separately, the ignition temperature and time can meet the requirements of GB / T19666-2019 fire resistance performance table 6 separately or simultaneously (fire supply temperature 950℃~1000℃, 90min ignition + 15min cooling, test voltage rated voltage, according to GB / T19216.21 test method, the line integrity meets the requirements of 2A fuse breaking and indicator light not going out), GA306.2-2007 fire resistance performance level and technical requirements table 1 specifies IA level (complaint with the fire resistance characteristics of GB / T19216 test method and smoke toxicity complies with ZA2 level in GB / T20285, smoke density ≥80%, corrosion resistance PH value ≥4.3, conductivity ≤10μs / mm).

[0022] The insulating layer includes a radiation cross-linked polyethylene layer 3 and a radiation cross-linked polyolefin layer 4 which are arranged in sequence from the inside to the outside. The inner layer has excellent electrical and mechanical properties and temperature resistance grade, and the outer layer has halogen-free, low-smoke and flame-retardant properties, which greatly improve the internal temperature resistance and flame-retardant properties of the cable, effectively protect the conductor 1, and improve the safety of the cable in the place of use and the continuous power supply time when a fire occurs, so as to facilitate emergency rescue measures, thereby ensuring the safety of people and property.

[0023] In practical applications, the radiation cross-linked polyethylene layer 3 and the radiation cross-linked polyolefin layer 4 adopt double-layer co-extrusion technology, and are cross-linked by high-energy rays generated by an electron accelerator after extrusion. The three-dimensional network molecular structure has good thermal stability after cross-linking, and the insulation electrical properties and mechanical properties are greatly improved, meeting the insulation performance requirements in GB / T12706-2020 and JB / T10491-2022. It also meets the long-life performance requirements in JG / T442-2014 (the long-term maximum operating temperature of conductor 1 is 125°C, the test temperature is 180±3°C, the test time is 168h, and the elongation at break retention rate should not be less than 50% of the original value of the elongation at break) and insulation performance requirements (the maximum operating temperature of conductor 1 is 150°C, and under the conditions of 200±3°C, the elongation under load before aging is not more than 80%, and the permanent elongation after cooling should not be more than 15%; the change rate of tensile strength after aging should not be greater than ±30%, and the elongation at break should not be greater than ±30%). The double-layer insulation co-extrusion radiation cross-linked insulation technology is adopted to increase the normal operating temperature of the cable to 150°C, ensuring the power safety and low-carbon environmental protection of the transmission line.

[0024] The filling layer 5 is an inorganic paper rope, also called an inorganic flame-retardant rope, which has environmental protection and flame-retardant properties.

[0025] The protective layer includes a first wrapping tape layer 6, an oxygen barrier layer 7 and a second wrapping tape layer 8 from the inside to the outside. The first wrapping tape layer 6 and the second wrapping tape layer 8 are both formed by bundling two layers of halogen-free oxygen barrier tapes. The halogen-free oxygen barrier tapes are highly flame-retardant. The first wrapping tape layer 6 protects the filling layer 5 and increases the flame-retardant and heat-dissipating properties. The purpose of the second wrapping tape layer 8 is to meet the d0 requirement of B1 in GB / T31247-2014, to prevent the release of gas at high temperature during combustion, causing the oxygen barrier layer 7 to have precipitates or protrusions. Wrapping and bundling are conducive to tightly wrapping the sheath 9 to prevent the sheath 9 from carbonizing and falling off.

[0026] The oxygen-isolating layer 7 is made of B1-grade ceramicized halogen-free low-smoke polyolefin, which can form a hard ceramic shell under flame burning or high temperature conditions, and plays a good role in fire protection. The oxygen index of the oxygen-isolating layer 7 material is greater than 40, and there is no precipitate or carbonization into a shell under high-temperature combustion. It has the characteristics of heat absorption, heat dissipation, flame retardancy, halogen-free and low-smoke, and can effectively form a double protective layer of the cable with the sheath 9, which can effectively prevent oxygen from acting as a combustion aid to continuously burn the cable, and has a good flame retardant effect. At the same time, it can implement external mechanical performance protection for the cable insulation core, making the cable safe and reliable during long-term operation.

[0027] The sheath 9 adopts B1 grade halogen-free low-smoke polyolefin. The material has high shell forming properties and good dripping properties. The flame retardant properties, dripping / particle level, smoke toxicity level and corrosiveness level during cable combustion meet the combustion performance B1 (d0, t0, a1) in GB31247-2014 and the bundled performance Class A and single flame retardant performance in GB / T19666-2019.

[0028] Embodiment 2

[0029] This embodiment is further optimized on the basis of the first embodiment. Specifically, according to the use requirements, this embodiment can design a metal shielding layer outside the sheath 9 to play a role in resisting electromagnetic interference, or design a metal armor layer according to the requirements of the laying site to protect the internal structure of the cable core from external force damage, and play a role in resisting tension and compression. In other embodiments, the outer sheath 9 can also be combined with the laying geographical environment to adopt low-smoke halogen-free flame retardant materials that meet the high flame retardant B1 grade performance and have the characteristics of anti-rat, anti-ant, etc., and can also be combined with waterproof, cold-resistant, radiation-proof, aging-resistant and other characteristics to optimize the structure.

[0030] The cable provided by this application can be widely used in infrastructure, factories, industrial and civil buildings, industrial devices, etc. in all walks of life, and can be used in densely populated places including high-rise buildings, subways, tunnels, shopping malls, theaters, stations, airports, and important distribution lines, building wiring, etc. The product has excellent insulation electrical and mechanical properties while meeting the performance of halogen-free, low-smoke and flame-retardant, with a service life of more than 70 years, high temperature resistance, high flame retardancy, energy saving and environmental protection, fire prevention, and a service life of not less than 70 years, which is synchronized with the 70-year property rights of the building. The long life ensures the safety of the cable, and will not generate secondary costs due to cable replacement. The comprehensive economic benefits are high. The cable meets the new building design specifications of the Ministry of Housing and Urban-Rural Development.

[0031] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A highly flame-retardant and fire-resistant power cable, comprising a plurality of cable cores, a filling layer (5) is arranged between the plurality of cable cores, a protective layer and a sheath (9) are arranged outside the filling layer (5) in sequence from the inside to the outside, and the cable core comprises a conductor (1), a fire-resistant layer (2) and an insulating layer arranged in sequence from the inside to the outside, characterized in that: The insulating layer comprises a radiation cross-linked polyethylene layer (3) and a radiation cross-linked polyolefin layer (4) which are arranged in sequence from the inside to the outside; The protective layer comprises, from the inside to the outside, a first wrapping tape layer (6), an oxygen barrier layer (7) and a second wrapping tape layer (8).

2. The highly flame-retardant and fire-resistant power cable according to claim 1, characterized in that: The first wrapping tape layer (6) and the second wrapping tape layer (8) are both formed by bundling two layers of halogen-free oxygen-isolating tapes.

3. The highly flame-retardant and fire-resistant power cable according to claim 1, characterized in that: The oxygen isolation layer (7) is made of B1 grade ceramic halogen-free low-smoke polyolefin.

4. The highly flame retardant and fire resistant power cable according to any one of claims 1 to 3, characterized in that: The sheath (9) is made of B1 grade halogen-free low-smoke polyolefin.

5. The highly flame retardant and fire resistant power cable according to any one of claims 1 to 3, characterized in that: The filling layer (5) is an inorganic paper rope.

6. The highly flame retardant and fire resistant power cable according to any one of claims 1 to 3, characterized in that: The fire-resistant layer (2) is a double-layer mica tape.

7. The highly flame retardant and fire resistant power cable according to any one of claims 1 to 3, characterized in that: The sheath (9) is provided with an armor layer or a metal shielding layer outside.

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