Low-smoke halogen-free flame-retardant B1-level mineral insulated aluminum alloy fireproof cable

Abstract

The invention discloses a low-smoke halogen-free flame-retardant B1-level mineral insulated aluminum alloy fireproof cable, which comprises a cable core, the cable core comprises a plurality of wire cores which are twisted together to form the cable core and a cable sheath which wraps the cable core, a filling layer is arranged in a gap in the cable sheath except for the wire cores, a reinforcing rope is arranged in the center of the plurality of wire cores, and the reinforcing rope is arranged in the cable sheath. The plurality of wire cores and a reinforcing rope are twisted together to form a cable core. The cable sheath sequentially comprises a belting layer, an inner protection layer, a mineral insulation layer, a fireproof layer, an isolation layer and an outer protection layer from inside to outside. On the premise of meeting power transmission, the fireproof cable not only has the characteristics of no halogen, low smoke and no toxicity, but also can reduce the manufacturing cost, reduce the weight of the cable and enhance the tensile strength of the cable, thereby meeting the use requirements of the B1-level fireproof cable, and being simple in overall structure, reasonable in design and worthy of popularization and application.

Description

Technical Field

[0001] The invention relates to the technical field of power cables, in particular to a low-smoke, halogen-free, flame-retardant B1-grade mineral-insulated aluminum alloy fireproof cable. Background Art

[0002] Cables are indispensable power and signal transmission facilities in modern industry. With the advancement of technology, there are many types of cables and many materials of cables, which can meet the needs of cable use in different occasions. With the acceleration of urbanization and modernization in my country, the domestic power system has also developed rapidly, and the demand for cables and the required standards have also been continuously improved. Commonly used flame-retardant and fire-resistant wires and cables are used. Since their sheath materials are mostly polyvinyl chloride, which is a halogen-containing material, if a fire occurs, such as a fire accident, a large amount of halogen acid gas and thick smoke will be released during the combustion of the cable. Halogen acid gas can cause poisoning, and thick smoke can cause suffocation and block vision, which is not conducive to ensuring the life safety of on-site personnel. Therefore, mineral insulated cables have been promoted and applied. Most of the mineral insulated cables currently used are copper core conductors. Due to the high cost of copper, it not only increases the processing cost of enterprises, but also increases the cost of users, resulting in an increasing demand for conductors made of other materials instead of copper cores. Among metal materials, aluminum has the advantages of good conductivity, light weight and low price, so it is a general trend to replace copper core cables with aluminum core cables. However, ordinary aluminum core cables have poor mechanical properties and corrosion resistance and cannot meet the application requirements of B1 grade cables.

[0003] According to the requirements of the currently implemented GB 51348-2019 "Electrical Design Standards for Civil Buildings", clear provisions have been made on the combustion performance of wires and cables and the selection of places of use. Article 8.9.1 stipulates that fire-resistant cables should have a flame retardant performance of not less than B1; Article 13.8.4 stipulates that in crowded places, the alarm bus of the automatic fire alarm system used in the evacuation passage should choose wires and cables with a combustion performance of B1; Article 13.9.1 stipulates that the combustion performance level of wires and cables laid in public buildings and refuge floors (rooms) with a building height of more than 100m should not be lower than B1; financial buildings in Class I high-rise buildings, provincial power dispatching buildings, provincial (municipal) radio and television, telecommunications buildings and crowded public places should also choose B1-level wires and cables. In actual use, whether it is during installation, maintenance or use, the wires will be dragged, which requires the wires and cables to have good flexibility, which puts higher requirements on B1-level cables.

[0004] After searching, the patent document with application publication number CN114334254A discloses a low-smoke halogen-free flame-retardant Class A B1 isolated mineral insulated fireproof cable, while the patent document with application publication number CN115512876A discloses an inorganic mineral insulated isolated B1 flame-retardant high-temperature fire-resistant cable, and the patent document with application publication number CN118039236A discloses a mineral insulated B1 flame-retardant fireproof cable. From the contents disclosed in the three retrieved patent documents, a fireproof cable with use requirements is provided from different angles. With the gradual expansion of the application scope of B1 fireproof cable, a large number of cables are needed to meet the use requirements of places with high density of people such as high-rise buildings, schools, various stations and hospitals, and to avoid fire accidents caused by short circuit of cables during long-term use, and reduce safety hazards. At the same time, in order to enhance the competitiveness of enterprises, adapt to market demand, and increase market share, a fireproof cable different from the one disclosed in the prior art is provided to meet the use requirements. Summary of the invention

[0005] The technical problem to be solved by the present invention is to address the problems existing in the background technology, thereby providing a fireproof cable with a simple structure and stable performance. The fireproof cable not only has the characteristics of halogen-free, low-smoke and non-toxic properties while meeting the requirements of power transmission, but also can reduce the production cost, reduce the weight of the cable, and enhance its tensile strength, thereby meeting the use requirements of B1 class fireproof cables. Specifically, it is a low-smoke, halogen-free, flame-retardant B1 class mineral insulated aluminum alloy fireproof cable.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a low-smoke halogen-free flame-retardant B1 grade mineral insulated aluminum alloy fireproof cable, comprising a cable core, the cable core comprising a plurality of wire cores twisted together to form a cable core, and a cable sheath coated on the cable core, and a filling layer is provided in the gaps in the cable sheath except for the wire cores, a reinforcing rope is provided in the center of the plurality of wire cores, and the plurality of wire cores and the reinforcing rope are twisted together to form a cable core; the cable sheath comprises a tape layer, an inner protective layer, a mineral insulation layer, a fireproof layer, an isolation layer and an outer protective layer from the inside to the outside, wherein the tape layer is formed by wrapping a halogen-free low-smoke flame-retardant tape, the mineral insulation layer is formed by winding a mica tape, the fireproof layer is formed by extruding a ceramic silicone rubber material, the isolation layer is formed by extruding a fireproof mud, and the inner protective layer and the outer protective layer are both formed by extruding a halogen-free low-smoke flame-retardant cross-linked polyolefin.

[0007] Furthermore, a low-smoke, halogen-free, flame-retardant, B1-grade mineral insulated aluminum alloy fireproof cable described in the present invention is used, wherein the wire core includes a conductor, a mica tape wrapping layer coated on the conductor, a conductor insulation layer extruded on the mica tape wrapping layer, and a conductor outer sheath extruded on the conductor insulation layer, wherein the mica tape wrapping layer is formed by wrapping mica tape with a paper coating, the conductor insulation layer is formed by extruding an EPDM rubber material, and the conductor outer sheath is formed by extruding a polyurethane material.

[0008] Furthermore, the low-smoke, halogen-free, flame-retardant, B1-grade mineral insulated aluminum alloy fireproof cable of the present invention is used, wherein the conductor is formed by hingedly connecting a plurality of heat-resistant aluminum alloy conductors, and the heat-resistant aluminum alloy conductor is prepared by an aluminum alloy rod, and the preparation method thereof comprises the following steps: S1. An aluminum alloy rod with a diameter of 8.5-12 mm is used as a raw material and pre-drawn at room temperature to obtain an aluminum alloy filament wire blank; S2. heat treating the pre-drawn aluminum alloy filament wire blank; S3. The heat-treated aluminum alloy filament wire billet is subjected to secondary drawing by a wire drawing machine to obtain aluminum alloy filaments; S4. Annealing the aluminum alloy filaments obtained by secondary drawing; S5. The annealed aluminum alloy filaments are twisted, re-twisted and heat treated to obtain heat-resistant deformation-resistant aluminum alloy filaments; S6. The heat-resistant deformable aluminum alloy single wires after heat treatment are twisted by a wire bundling machine and twisted together by a wire splitter to obtain a heat-resistant aluminum alloy conductor.

[0009] Furthermore, the low-smoke, halogen-free, flame-retardant, B1-grade mineral insulated aluminum alloy fireproof cable of the present invention is used, and the specific operation mode of step S1 is: firstly, the aluminum alloy rod raw material is pre-drawn at room temperature using a billet drawing die to obtain an aluminum alloy thick wire, and the drawing speed of the drawing process is 5 to 10 m / s; then, the aluminum alloy thick wire obtained by the pre-drawing is drawn again through the billet drawing die to be drawn into an aluminum alloy fine wire billet, and the drawing speed of the drawing process is 10 to 15 m / s; The specific operation of S2 is: heating, heat preservation and cooling the aluminum alloy fine wire blank obtained by pre-drawing, firstly raising the temperature to 335-345°C, then maintaining the temperature for 10-14 hours, and finally reducing the temperature to 60°C, and then waiting for the aluminum alloy fine wire blank to cool naturally in the air; The specific operation of S3 is: using a wire drawing machine to draw the heat-treated aluminum alloy filament wire blank, and controlling the drawing speed to be 20-30 m / min, so that the wire blank is automatically wound into a coil on the wire drawing machine; The specific operation of S4 is: heating, heat preservation and cooling the aluminum alloy filaments obtained by secondary drawing, firstly raising the temperature to 480-520°C, then maintaining the temperature for 8-12 hours, and finally reducing the temperature to 120°C, waiting for the aluminum alloy filaments to cool naturally in the air, so as to obtain the aluminum alloy single wire; The specific operation of S5 is: the aluminum alloy single wire obtained after annealing treatment is subjected to stranding by a wire bundling machine, the stranded wire core is subjected to re-twisting by a cage-type stranding machine, and the number of strands is determined according to the wire diameter of the single aluminum alloy wire, and finally the stranded aluminum alloy wire is placed in a high-temperature aging furnace at 420° C. to 450° C. for heat treatment, and the aging time is 4 to 6 hours, and the heat-resistant deformation aluminum alloy conductor single wire is obtained after the heat treatment; The specific operation method of S6 is: the heat-resistant deformable aluminum alloy single wires are rewound onto the reels respectively, and are evenly arranged in layers on the wire bundling machine, and are twisted together in a Z-direction spiral through a wire distribution plate, and the twisting pitch is not greater than 10 times the twisting outer diameter, and the cross-sectional shape of the heat-resistant aluminum alloy conductor obtained after twisting is close to a full circle.

[0010] Furthermore, the low-smoke halogen-free flame-retardant B1-class mineral insulated aluminum alloy fireproof cable described in the present invention is used, and the filling layer is filled with halogen-free flame-retardant glass fiber yarns.

[0011] Furthermore, the low-smoke, halogen-free, flame-retardant B1-class mineral insulated aluminum alloy fireproof cable described in the present invention is used, and the reinforcing rope is formed by winding an aramid fiber material.

[0012] Furthermore, the low-smoke, halogen-free, flame-retardant B1-class mineral insulated aluminum alloy fireproof cable described in the present invention is adopted, and the tape layer is formed by double-layer wrapping of halogen-free, low-smoke, flame-retardant tape.

[0013] Furthermore, a low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable described in the present invention is used, wherein the mineral insulation layer is formed by winding multiple layers of synthetic mica tapes, the mica tape layer includes a three-in-one synthetic mica tape, and the mica tape layer is a three-layer overlapping winding structure.

[0014] Furthermore, a low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable as described in the present invention is used, wherein the isolation layer is a mixture of fireproof mud composed of water glass, clay powder, magnesium hydroxide and aluminum powder in a weight ratio of (30-50):(50-70):(75-90):(15-25), which is melt-extruded and coated on the outside of the fireproof layer by an extruder, and then cooled and solidified to obtain the insulation layer.

[0015] Furthermore, the low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable described in the present invention is used, wherein the wire cores include five wire cores, which are arranged on the outside of the reinforcing rope in an external tangential state and twisted together with the reinforcing rope to form a cable core.

[0016] Compared with the prior art, the low-smoke, halogen-free, flame-retardant, B1-grade mineral insulated aluminum alloy fireproof cable of the present invention has the following beneficial effects: first, the conductor in the core is formed by twisting a plurality of heat-resistant aluminum alloy conductors, and the heat-resistant aluminum alloy conductor is formed by twisting hot aluminum alloy monofilaments. The heat-resistant aluminum alloy conductor can be used at a higher temperature without softening, and can work safely for a long time at a temperature of 150 to 300°C, which can meet the use requirements of the cable in a high temperature environment. Compared with the existing copper core cable, it can not only improve the mechanical properties and creep resistance of the conductor, but also improve the mechanical properties of the conductor. The first is to improve the properties of the cable and electrical performance, and also make the cable lighter, thereby reducing the weight of the cable and reducing the processing cost; secondly, a reinforcing rope made of aramid fiber material is provided in the center of the multiple cores, so as to improve the overall tensile strength of the cable core; thirdly, a filling layer is provided in the gaps outside the cores in the cable sheath, and the cable sheath comprises a tape layer, an inner protective layer, a mineral insulation layer, a fireproof layer, an isolation layer and an outer protective layer from the inside to the outside. By adopting the above structure, the bending performance and fireproof performance of the cable are greatly improved, and it also has the characteristics of flame retardancy, halogen-free, low smoke and non-toxicity.

[0017] It can be seen that the fireproof cable described in the present invention, under the premise of meeting the power transmission requirements, not only has the characteristics of halogen-free, low smoke and non-toxic properties, but also can reduce the production cost, reduce the weight of the cable, and enhance its tensile strength, thereby meeting the use requirements of B1 class fireproof cable. Its overall structure is simple and the design is reasonable, and it is worthy of popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0019] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a structural schematic diagram of the wire core described in the present invention.

[0020] As shown in the figure: 1-wire core, 11-conductor, 12-mica tape wrapping layer, 13-conductor insulation layer, 14-conductor outer sheath, 2-filling layer, 3-reinforcement rope, 4-tape layer, 5-inner sheath, 6-mineral insulation layer, 7-fireproof layer, 8-isolation layer, 9-outer sheath. DETAILED DESCRIPTION

[0021] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0022] It should be noted that the structures, proportions, sizes, etc. drawn in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", etc. quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "provided with" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] It should be noted that the term "comprise" or any other variation is intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0025] like Figure 1 and Figure 2 As shown, a low-smoke, halogen-free, flame-retardant, B1-grade mineral insulated aluminum alloy fireproof cable according to the present invention comprises a cable core, wherein the cable core comprises a plurality of cores 1 twisted together to form a cable core, and a cable sheath coated on the cable core, and a filling layer 2 is provided in the gaps in the cable sheath except for the cores 1, and a reinforcing rope 3 is provided in the center of the plurality of cores 1, and the plurality of cores 1 and the reinforcing rope 3 are twisted together to form a cable core; the cable sheath comprises a tape layer 4, an inner protective layer 5, a mineral insulating layer 6, a fireproof layer 7, an isolating layer 8 and an outer protective layer 9 from the inside to the outside, wherein the tape layer 4 is formed by wrapping a halogen-free, low-smoke, flame-retardant tape, the mineral insulating layer 6 is formed by winding a mica tape, the fireproof layer 7 is formed by extruding a ceramic silicone rubber material, the isolating layer 8 is formed by extruding a fireproof mud, and the inner protective layer 5 and the outer protective layer 9 are both formed by extruding a halogen-free, low-smoke, flame-retardant cross-linked polyolefin.

[0026] The low-smoke, halogen-free, flame-retardant, B1-grade mineral insulated aluminum alloy fireproof cable described in the present invention is used. In a specific preparation process, the wire core 1 includes five wire cores, which are arranged on the outside of the reinforcing rope 3 in an external tangential state and twisted together with the reinforcing rope 3 to form a cable core; wherein the wire core 1 includes a conductor 11, a mica tape wrapping layer 12 coated on the conductor 11, a conductor insulation layer 13 extruded on the mica tape wrapping layer 12, and a conductor outer sheath 14 extruded on the conductor insulation layer 13, wherein the mica tape wrapping layer 12 is formed by wrapping mica tape with a paper coating, the conductor insulation layer 13 is extruded from an EPDM rubber material, and the conductor outer sheath 14 is extruded from a polyurethane material; and the conductor 11 is formed by hingedly joining a plurality of heat-resistant aluminum alloy conductors, and the heat-resistant aluminum alloy conductor is prepared from an aluminum alloy rod, and the preparation method thereof includes the following steps: S1. An aluminum alloy rod with a diameter of 8.5-12 mm is used as a raw material and pre-drawn at room temperature to obtain an aluminum alloy filament wire blank; S2. heat treating the pre-drawn aluminum alloy filament wire blank; S3. The heat-treated aluminum alloy filament wire billet is subjected to secondary drawing by a wire drawing machine to obtain aluminum alloy filaments; S4. Annealing the aluminum alloy filaments obtained by secondary drawing; S5. The annealed aluminum alloy filaments are twisted, re-twisted and heat treated to obtain heat-resistant deformation-resistant aluminum alloy filaments; S6. The heat-resistant deformable aluminum alloy single wires after heat treatment are twisted by a wire bundling machine and twisted together by a wire splitter to obtain a heat-resistant aluminum alloy conductor.

[0027] Furthermore, a low-smoke, halogen-free, flame-retardant B1 grade mineral insulated aluminum alloy fireproof cable described in the present invention is adopted, the filling layer 2 is filled with halogen-free, flame-retardant glass fiber yarn, the reinforcing rope 3 is wound with aromatic amide fiber material, the wrapping layer 4 is double-wrapped with halogen-free, low-smoke, flame-retardant wrapping tape, the mineral insulation layer 6 is wound with multiple layers of synthetic mica tape, the mica tape layer includes a three-in-one synthetic mica tape, and the mica tape layer is a three-layer overlapping wrapping structure. Example 1

[0028] This embodiment provides a specific preparation method of the heat-resistant aluminum alloy conductor. The heat-resistant aluminum alloy conductor is prepared by using an aluminum alloy rod. The preparation method includes the following steps: S1. Using an aluminum alloy rod with a diameter of 8.5 mm as a raw material, pre-drawing is performed at room temperature to obtain an aluminum alloy fine wire blank. The specific operation method is: first, the aluminum alloy rod raw material is pre-drawn at room temperature using a billet drawing die to obtain an aluminum alloy thick wire, and the drawing speed of the drawing process is 5 m / s; then the aluminum alloy thick wire obtained by pre-drawing is drawn again through the billet drawing die to obtain an aluminum alloy fine wire blank through drawing, and the drawing speed of the drawing process is 10 m / s; S2. heat treating the aluminum alloy fine wire blank obtained by pre-drawing, specifically, heating, keeping and cooling the aluminum alloy fine wire blank obtained by pre-drawing, firstly raising the temperature to 335° C., then maintaining the temperature for 14 hours, and finally lowering the temperature to 60° C., and then waiting for the aluminum alloy fine wire blank to cool naturally in the air; S3. The heat-treated aluminum alloy filament billet is subjected to secondary drawing by a wire drawing machine to obtain aluminum alloy filaments, wherein the specific operation is as follows: the heat-treated aluminum alloy filament billet is drawn by a wire drawing machine, and the drawing speed is controlled at 20 m / min, so that the billet is automatically wound into a coil on the wire drawing machine; S4. Annealing the aluminum alloy filaments obtained by the secondary drawing; the specific operation method is: heating, heat preservation and cooling the aluminum alloy filaments obtained by the secondary drawing, first raising the temperature to 480°C, then maintaining the temperature for 12 hours, and finally lowering the temperature to 120°C, waiting for the aluminum alloy filaments to cool naturally in the air, that is, obtaining an aluminum alloy single wire; S5. The aluminum alloy filaments after annealing are twisted, re-twisted and heat-treated to obtain heat-resistant deformation aluminum alloy monofilaments. The specific operation method is: the aluminum alloy single wires obtained after annealing are twisted into strands by a wire bundler, the stranded strand cores are re-twisted by a cage stranding machine, and the number of strands is determined according to the wire diameter of a single aluminum alloy wire. Finally, the twisted aluminum alloy wires are placed in a high-temperature aging furnace at 420°C for heat treatment for 6 hours. After the heat treatment, the heat-resistant deformation aluminum alloy conductor monofilament is obtained; S6. The heat-resistant deformed aluminum alloy monofilaments after heat treatment are twisted by a wire bundling machine, and twisted together by a wire splitter to obtain a heat-resistant aluminum alloy conductor. The specific operation method is: the heat-resistant deformed aluminum alloy monofilaments are rewound onto the reel respectively, and arranged in layers on the wire bundling machine evenly, and twisted together by a wire splitter in a Z-direction spiral, and the twisted pitch is not greater than 10 times the twisted outer diameter. The cross-sectional shape of the heat-resistant aluminum alloy conductor obtained after twisting is close to a full circle. Finally, combined with the nominal area of ​​the cable core, according to the conventional method, multiple heat-resistant aluminum alloy conductors are selected to be twisted into a conductor 11, and the surface of the twisted conductor body 11 is bright, the pitch is uniform, the outer diameter of the conductor is round and uniform, and there is no skipped wire, burr, broken wire and thinning phenomenon. Then, the mica tape wrapping layer 12, the conductor insulation layer 13 and the conductor outer sheath 14 are coated on the outside of the conductor body 11 in sequence from the inside to the outside according to the conventional method, so as to obtain the wire core 1.

[0029] This embodiment also provides the specific composition of the fireproof mud used in the isolation layer 8. The isolation layer 8 is composed of a mixture of water glass, clay powder, magnesium hydroxide and aluminum powder in a weight ratio of 30:70:80:20. It is melt-extruded and coated on the outside of the fireproof layer 7 by an extruder, and then cooled and solidified to obtain the obtained fireproof mud. Example 2

[0030] This embodiment provides a specific preparation method of the heat-resistant aluminum alloy conductor. The heat-resistant aluminum alloy conductor is prepared by using an aluminum alloy rod. The preparation method includes the following steps: S1. Using an aluminum alloy rod with a diameter of 10 mm as a raw material, pre-drawing is performed at room temperature to obtain an aluminum alloy fine wire blank. The specific operation method is: first, the aluminum alloy rod raw material is pre-drawn at room temperature using a billet drawing die to obtain an aluminum alloy thick wire, and the drawing speed of the drawing process is 8 m / s; then the aluminum alloy thick wire obtained by the pre-drawing is drawn again through the billet drawing die to obtain an aluminum alloy fine wire blank through drawing, and the drawing speed of the drawing process is 12 m / s; S2. heat treating the aluminum alloy fine wire billet obtained by pre-drawing, specifically, heating, keeping and cooling the aluminum alloy fine wire billet obtained by pre-drawing, firstly raising the temperature to 340° C., then maintaining the temperature for 12 hours, and finally lowering the temperature to 60° C., and then waiting for the aluminum alloy fine wire billet to cool naturally in the air; S3. The heat-treated aluminum alloy filament billet is subjected to secondary drawing by a wire drawing machine to obtain aluminum alloy filaments, wherein the specific operation is as follows: the heat-treated aluminum alloy filament billet is drawn by a wire drawing machine, and the drawing speed is controlled at 25 m / min, so that the billet is automatically wound into a coil on the wire drawing machine; S4. Annealing the aluminum alloy filaments obtained by the secondary drawing; the specific operation method is: heating, keeping and cooling the aluminum alloy filaments obtained by the secondary drawing, first raising the temperature to 500°C, then maintaining the temperature for 10 hours, and finally lowering the temperature to 120°C, waiting for the aluminum alloy filaments to cool naturally in the air, that is, obtaining the aluminum alloy single wire; S5. The aluminum alloy filaments after annealing are twisted, re-twisted and heat-treated to obtain heat-resistant deformation aluminum alloy monofilaments. The specific operation method is: the aluminum alloy single wires obtained after annealing are twisted into strands by a wire bundling machine, the stranded strand cores are re-twisted by a cage-type stranding machine, and the number of strands is determined according to the wire diameter of a single aluminum alloy wire. Finally, the twisted aluminum alloy wires are placed in a high-temperature aging furnace at 435°C for heat treatment for 5 hours. After the heat treatment, the heat-resistant deformation aluminum alloy conductor monofilament is obtained; S6. The heat-resistant deformed aluminum alloy monofilaments after heat treatment are twisted by a wire bundling machine, and twisted together by a wire splitter to obtain a heat-resistant aluminum alloy conductor. The specific operation method is: the heat-resistant deformed aluminum alloy monofilaments are rewound onto the reel respectively, and arranged in layers on the wire bundling machine evenly, and twisted together by a wire splitter in a Z-direction spiral, and the twisted pitch is not greater than 10 times the twisted outer diameter. The cross-sectional shape of the heat-resistant aluminum alloy conductor obtained after twisting is close to a full circle. Finally, combined with the nominal area of ​​the cable core, according to the conventional method, multiple heat-resistant aluminum alloy conductors are selected to be twisted into a conductor 11, and the surface of the twisted conductor body 11 is bright, the pitch is uniform, the outer diameter of the conductor is round and uniform, and there is no skipped wire, burr, broken wire and thinning phenomenon. Then, the mica tape wrapping layer 12, the conductor insulation layer 13 and the conductor outer sheath 14 are coated on the outside of the conductor body 11 in sequence from the inside to the outside according to the conventional method, so as to obtain the wire core 1.

[0031] This embodiment also provides the specific composition of the fireproof mud used in the isolation layer 8. The isolation layer 8 is composed of a mixture of water glass, clay powder, magnesium hydroxide and aluminum powder in a weight ratio of 40:60:85:15. It is melt-extruded and coated on the outside of the fireproof layer 7 by an extruder, and then cooled and solidified to obtain the obtained fireproof mud. Example 3

[0032] This embodiment provides a specific preparation method of the heat-resistant aluminum alloy conductor. The heat-resistant aluminum alloy conductor is prepared by using an aluminum alloy rod. The preparation method includes the following steps: S1. Using an aluminum alloy rod with a diameter of 12 mm as a raw material, pre-drawing is performed at room temperature to obtain an aluminum alloy fine wire blank. The specific operation method is: first, the aluminum alloy rod raw material is pre-drawn at room temperature using a billet drawing die to obtain an aluminum alloy thick wire, and the drawing speed of the drawing process is 10 m / s; then the aluminum alloy thick wire obtained by pre-drawing is drawn again through the billet drawing die to obtain an aluminum alloy fine wire blank through drawing, and the drawing speed of the drawing process is 15 m / s; S2. heat treating the aluminum alloy fine wire blank obtained by pre-drawing, specifically, heating, keeping and cooling the aluminum alloy fine wire blank obtained by pre-drawing, firstly raising the temperature to 345° C., then maintaining the temperature for 10 hours, and finally lowering the temperature to 60° C., and then waiting for the aluminum alloy fine wire blank to cool naturally in the air; S3. The heat-treated aluminum alloy filament billet is subjected to secondary drawing by a wire drawing machine to obtain aluminum alloy filaments, wherein the specific operation is as follows: the heat-treated aluminum alloy filament billet is drawn by a wire drawing machine, and the drawing speed is controlled at 30 m / min, so that the billet is automatically wound into a coil on the wire drawing machine; S4. The aluminum alloy filaments obtained by the secondary drawing are annealed; the specific operation method is: the aluminum alloy filaments obtained by the secondary drawing are heated, kept and cooled, the temperature is first raised to 520°C, then maintained at this temperature for 8 hours, and finally the temperature is reduced to 120°C, and the aluminum alloy filaments are allowed to cool naturally in the air, that is, the aluminum alloy single wire is obtained; S5. The aluminum alloy filaments after annealing are twisted, re-twisted and heat-treated to obtain heat-resistant deformation aluminum alloy monofilaments. The specific operation method is: the aluminum alloy single wires obtained after annealing are twisted into strands by a wire bundling machine, the stranded strand cores are re-twisted by a cage-type stranding machine, and the number of strands is determined according to the wire diameter of a single aluminum alloy wire. Finally, the twisted aluminum alloy wires are placed in a high-temperature aging furnace at 450° C. for heat treatment for 4 hours. After the heat treatment, the heat-resistant deformation aluminum alloy conductor monofilament is obtained; S6. The heat-resistant deformable aluminum alloy monofilaments after heat treatment are twisted by a wire bundling machine, and twisted together by a wire dividing plate to obtain a heat-resistant aluminum alloy conductor. The specific operation method is: the heat-resistant deformable aluminum alloy monofilaments are rewound onto the reels respectively, and arranged in layers on the wire bundling machine evenly, and twisted together by a wire dividing plate in a Z-direction spiral, and the twisted pitch is not greater than 10 times the twisted outer diameter. The cross-sectional shape of the heat-resistant aluminum alloy conductor obtained after twisting is close to a full circle; finally, based on the nominal area of ​​the cable core, a plurality of heat-resistant aluminum alloy conductors are selected according to conventional methods to be twisted into a conductor 11, and the surface of the twisted conductor body 11 is bright, the pitch is uniform, the outer diameter of the conductor is round and uniform, and there is no skipped wire, burr, broken wire and thinning phenomenon. Then, the mica tape sheath 12, the conductor insulation layer 13 and the conductor outer sheath 14 are coated on the outside of the conductor body 11 in sequence from the inside to the outside according to conventional methods to obtain the wire core 1.

[0033] This embodiment also provides the specific composition of the fireproof mud used in the isolation layer 8. The isolation layer 8 is composed of a mixture of water glass, clay powder, magnesium hydroxide and aluminum powder in a weight ratio of 50:50:75:25. It is melt-extruded and coated on the outside of the fireproof layer 7 by an extruder, and then cooled and solidified to obtain the obtained fireproof mud.

[0034] In order to illustrate the performance of a low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable according to the present invention, the performance of the fireproof cable prepared by the conventional method using the wire core 1 and the isolation layer 8 prepared by the methods described in Examples 1 to 3 was tested: According to GB31247-2014 "Classification of Combustion Performance of Cables and Optical Cables", the B1 level combustion performance test is carried out on the samples; according to GB / T31248-2014 "Test Method for Flame Spread, Heat Release and Smoke Generation Characteristics of Cables or Optical Cables under Fire Conditions", the burning dripping / particle level is tested; it is required that there is no burning dripping / drip within 1200s, and the smoke toxicity level is t0; according to the test method of GB / T 20285-2006, it is required to reach ZA2, and the corrosive level is a1. The specific test results are shown in Table 1.

[0035] Table 1

[0036] From the test results in Table 1, it can be seen that the smoke toxicity levels meet the requirements, the burning drippings meet the requirements, and the data values ​​such as flame spread, heat release rate and vertical flame spread are all smaller than those of conventional cables. The flame retardant and fireproof properties meet the B1 level requirements.

[0037] The low-smoke, halogen-free, flame-retardant, B1-grade mineral insulated aluminum alloy fireproof cable described in the present invention has a reinforcing rope 3 wound with aramid fiber material at the center of the multiple wire cores 1 inside the cable core. Aramid, also known as aramid, is a synthetic fiber with excellent properties such as ultra-high strength, high modulus, high temperature resistance, acid and alkali resistance, and light weight. Its strength is 5 to 6 times that of steel wire, its modulus is 2 to 3 times that of steel wire or glass fiber, its toughness is 2 times that of steel wire, and its weight is only about 1 / 5 of that of steel wire. It does not decompose or melt at a temperature of 560 degrees. It also has good insulation and anti-aging properties and a long life cycle. The reinforcing rope 3 wound with aramid fiber material can improve the overall strength of the cable core.

[0038] A cable sheath is provided outside the cable core, and the cable sheath includes a tape layer 4, an inner protective layer 5, a mineral insulation layer 6, a fireproof layer 7, an isolation layer 8 and an outer protective layer 9 from the inside to the outside, wherein the tape layer 4 is formed by wrapping a halogen-free low-smoke flame-retardant tape, the mineral insulation layer 6 is formed by winding a mica tape, the fireproof layer 7 is formed by extruding a ceramic silicone rubber material, the isolation layer 8 is formed by extruding a fireproof mud, and the inner protective layer 5 and the outer protective layer 9 are both formed by extruding a halogen-free low-smoke flame-retardant cross-linked polyolefin. Since the fireproof layer 7 is formed by extruding a ceramic silicone rubber material, the ceramic silicone rubber material is a new type of polymer refractory material, and the ceramic silicone rubber has excellent fireproof, flame-retardant, low-smoke, non-toxic and other characteristics, and the extrusion molding process is simple. The residue after combustion is a hard ceramic shell, and the hard shell does not melt or drip in a fire environment. The hard shell after combustion plays a good protective role for the line. It can pass the line integrity test specified in GB / T19216.21-2003 at 950℃-1000℃, fire for 90min, and cooling for 15min. It is suitable for any place that needs fire protection, and plays a solid protective role in ensuring smooth power transmission in the event of fire. At the same time, since ceramic silicone rubber products have no special requirements for equipment, the processing technology is simple, and production can be achieved using traditional silicone rubber processing equipment. Compared with the current production process of fire-resistant wires and cables, it has higher production efficiency and can reduce production energy consumption and save costs. The isolation layer 8 is made of fireproof mud composed of water glass, clay powder, magnesium hydroxide and aluminum powder, which is melt-extruded and coated on the outside of the fireproof layer 7 by an extruder, and is prepared after cooling and solidification.

[0039] A double-layer fireproof and flame-retardant effect is formed by the fireproof layer 7 and the isolation layer 8, which can improve its flame retardant and fireproof performance and meet the requirements of GB 51348-2019 "Electrical Design Standards for Civil Buildings", and the tape layer 4 is wrapped with a halogen-free, low-smoke, flame-retardant tape, the mineral insulation layer 6 is wound with a mica tape, and the inner sheath 5 and the outer sheath 9 are both extruded with halogen-free, low-smoke, flame-retardant cross-linked polyolefin. Under the premise of meeting the flame retardant, halogen-free, low-smoke and non-toxic properties, the bending performance and fireproof performance of the cable can also be improved.

[0040] To sum up, the fireproof cable described in the present invention, under the premise of meeting the power transmission requirements, not only has the characteristics of halogen-free, low smoke and non-toxic properties, but also can reduce the production cost, reduce the weight of the cable, and enhance its tensile strength, thereby meeting the use requirements of B1 class fireproof cable. Its overall structure is simple and the design is reasonable, and it is worthy of popularization and use.

[0041] Other aspects of the present invention that are not described in detail are all conventional techniques known to those skilled in the art.

[0042] The protection scope of the present invention is not limited to the technical solutions disclosed in the specific implementation methods. The above description is only a preferred implementation method of the present invention and does not limit the present invention. Any minor modifications, equivalent substitutions and improvements made according to the technical solutions of the present invention should be included in the protection scope of the technical solutions of the present invention.

Claims

1. A low-smoke, halogen-free, flame-retardant, Class B1 mineral insulated aluminum alloy fireproof cable, comprising a cable core, the cable core comprising a plurality of wire cores (1) twisted together to form the cable core, and a cable sheath covering the cable core, and a filling layer (2) is provided in the gaps in the cable sheath except for the wire cores (1), characterized in that: A reinforcing rope (3) is provided at the center of the plurality of wire cores (1), and the plurality of wire cores (1) and the reinforcing rope (3) are twisted together to form a cable core; the cable sheath comprises, from the inside to the outside, a tape layer (4), an inner protective layer (5), a mineral insulating layer (6), a fireproof layer (7), an isolation layer (8) and an outer protective layer (9), wherein the tape layer (4) is formed by wrapping a halogen-free low-smoke flame-retardant tape, the mineral insulating layer (6) is formed by wrapping a mica tape, the fireproof layer (7) is formed by extruding a ceramic silicone rubber material, the isolation layer (8) is formed by extruding a fireproof mud, and the inner protective layer (5) and the outer protective layer (9) are both formed by extruding a halogen-free low-smoke flame-retardant cross-linked polyolefin.

2. According to claim 1, a low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable, characterized in that: The wire core (1) comprises a conductor (11), a mica tape wrapping layer (12) coated on the conductor (11), a conductor insulation layer (13) extruded on the mica tape wrapping layer (12), and a conductor outer sheath (14) extruded on the conductor insulation layer (13), wherein the mica tape wrapping layer (2) is formed by wrapping a mica tape with a paper coating, the conductor insulation layer (13) is formed by extruding an EPDM rubber material, and the conductor outer sheath (14) is formed by extruding a polyurethane material.

3. A low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable according to claim 2, characterized in that: The conductor (11) is formed by hingedly joining a plurality of heat-resistant aluminum alloy conductors, and the heat-resistant aluminum alloy conductor is prepared by using an aluminum alloy rod. The preparation method thereof comprises the following steps: S1. An aluminum alloy rod with a diameter of 8.5-12 mm is used as a raw material and pre-drawn at room temperature to obtain an aluminum alloy filament wire blank; S2. heat treating the pre-drawn aluminum alloy filament wire blank; S3. The heat-treated aluminum alloy filament wire billet is subjected to secondary drawing by a wire drawing machine to obtain aluminum alloy filaments; S4. Annealing the aluminum alloy filaments obtained by secondary drawing; S5. The annealed aluminum alloy filaments are twisted, re-twisted and heat treated to obtain heat-resistant deformation-resistant aluminum alloy filaments; S6. The heat-resistant deformable aluminum alloy single wires after heat treatment are twisted by a wire bundling machine and twisted together by a wire splitter to obtain a heat-resistant aluminum alloy conductor.

4. The low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable according to claim 3, characterized in that: The specific operation method of step S1 is: firstly, the aluminum alloy rod raw material is pre-drawn at room temperature using a billet drawing die to obtain an aluminum alloy thick wire, and the drawing speed of the drawing process is 5-10 m / s; then, the aluminum alloy thick wire obtained by pre-drawing is drawn again through the billet drawing die to obtain an aluminum alloy fine wire billet through drawing, and the drawing speed of the drawing process is 10-15 m / s; The specific operation of S2 is: heating, heat preservation and cooling the aluminum alloy fine wire blank obtained by pre-drawing, firstly raising the temperature to 335-345°C, then maintaining the temperature for 10-14 hours, and finally reducing the temperature to 60°C, and then waiting for the aluminum alloy fine wire blank to cool naturally in the air; The specific operation of S3 is: using a wire drawing machine to draw the heat-treated aluminum alloy filament wire blank, and controlling the drawing speed to be 20-30 m / min, so that the wire blank is automatically wound into a coil on the wire drawing machine; The specific operation of S4 is: heating, heat preservation and cooling the aluminum alloy filaments obtained by secondary drawing, firstly raising the temperature to 480-520°C, then maintaining the temperature for 8-12 hours, and finally reducing the temperature to 120°C, waiting for the aluminum alloy filaments to cool naturally in the air, so as to obtain the aluminum alloy single wire; The specific operation of S5 is: the aluminum alloy single wire obtained after annealing treatment is subjected to stranding by a wire bundling machine, the stranded wire core is subjected to re-twisting by a cage-type stranding machine, and the number of strands is determined according to the wire diameter of the single aluminum alloy wire, and finally the stranded aluminum alloy wire is placed in a high-temperature aging furnace at 420° C. to 450° C. for heat treatment, and the aging time is 4 to 6 hours, and the heat-resistant deformation aluminum alloy conductor single wire is obtained after the heat treatment; The specific operation method of S6 is: the heat-resistant deformable aluminum alloy single wires are rewound onto the reels respectively, and are evenly arranged in layers on the wire bundling machine, and are twisted together in a Z-direction spiral through a wire distribution plate, and the twisting pitch is not greater than 10 times the twisting outer diameter, and the cross-sectional shape of the heat-resistant aluminum alloy conductor obtained after twisting is close to a full circle.

5. The low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable according to claim 1, characterized in that: The filling layer (2) is filled with halogen-free flame-retardant glass fiber yarns.

6. The low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable according to claim 1, characterized in that: The reinforcing rope (3) is formed by winding an aramid fiber material.

7. The low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable according to claim 1, characterized in that: The tape layer (4) is formed by double-layer wrapping of halogen-free, low-smoke, flame-retardant tape.

8. The low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable according to claim 1, characterized in that: The mineral insulation layer (6) is formed by winding multiple layers of synthetic mica tapes, wherein the mica tape layer comprises a three-in-one synthetic mica tape, and the mica tape layer is a three-layer overlapping winding structure.

9. The low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable according to claim 1, characterized in that: The isolation layer (8) is prepared by melt extrusion and coating the outside of the fireproof layer (7) with a mixture of fireproof mud composed of water glass, clay powder, magnesium hydroxide and aluminum powder in a weight ratio of (30-50):(50-70):(75-90):(15-25). The mixture is cooled and solidified after being melt extruded by an extruder.

10. The low-smoke, halogen-free, flame-retardant B1-grade mineral insulated aluminum alloy fireproof cable according to claim 1, characterized in that: The wire cores (1) include five wire cores, which are arranged outside the reinforcing rope (3) in an external tangential state and are twisted together with the reinforcing rope (3) to form a cable core.

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