Flexible fireproof cable capable of resisting temperature of 1100 DEG C and production method

Abstract

The invention provides a flexible fireproof cable resistant to the temperature of 1100 DEG C and a production method, and relates to the technical field of special cables, and the flexible fireproof cable resistant to the temperature of 1100 DEG C comprises a conductor, a conductor fireproof layer, a heat insulation layer, a heat insulation layer protection layer and a metal layer which are sequentially arranged from inside to outside; the conductor fireproof layer is formed by wrapping an inorganic mineral composite belt; according to the inorganic mineral composite belt, inorganic silicate sodium silicate is used as a base material, any one or more of mica, kaolin, borate, glass powder, wollastonite, talcum powder, bentonite and aluminum hydroxide are added to serve as ceramic filler, and the mass ratio of the base material to the ceramic filler is 100: 75. The cable has the characteristics of high temperature resistance of 1100 DEG C, fire resistance, flame retardance, excellent electrical insulation performance, small outer diameter, light weight and excellent bending performance.

Description

Technical Field

[0001] The present invention relates to the technical field of special cables, and in particular to a flexible fireproof cable resistant to temperatures of 1100°C and a production method thereof. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] Electrical fires are one of the leading causes of fire accidents in my country. As the core carrier of power transmission, the ability of wires and cables to continuously provide power in fire conditions is directly related to the safe operation of key facilities such as firefighting equipment and alarm systems.

[0004] At present, the mainstream fire-resistant cables on the market are divided into two categories: (1) Traditional wrapped fire-resistant cable (NH type): mica tape is wrapped around the conductor, with a rated voltage of 0.6 / 1kV and below; (2) Mineral insulated cable (BTTZ / YTTW / RTTZ type): adopts copper sheathed inorganic mineral insulation structure, with a rated voltage of 500V / 750V.

[0005] The fire resistance limit of the above-mentioned fire-resistant cables does not exceed 1000°C. Among them, the fire resistance test temperature of traditional NH type cables is 750-950°C, and mineral insulated cables (BTTZ, etc.) can withstand 950-1000°C. However, the temperature at an extreme fire scene will exceed 1000°C. Therefore, at an extreme fire scene, the existing fire-resistant cables will be burned by the fire. In addition, the rigid metal sheath of the mineral insulated cable will lead to poor bending performance of the cable, which limits the application scenarios. At the same time, since the thermal expansion coefficient of the mica tape (mainly silicate) of the traditional wrapped cable is about 5×10 -6 / ℃, while the thermal expansion coefficient of the copper sheath of the mineral insulated cable is 17×10 -6 / °C, a difference of more than three times. At high temperatures above 800°C, the thermal expansion difference can lead to interfacial stress concentration, causing cracking of the wrapping layer or deformation of the sheath, destroying the integrity of the fire-resistant cable structure. Therefore, those skilled in the art have no motivation to improve and directly combine traditional NH-type cables with mineral-insulated cables. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a 1100℃ temperature-resistant flexible fireproof cable and a production method, which has the characteristics of high temperature resistance of 1100℃, fire resistance, flame retardancy, excellent electrical insulation performance, small outer diameter, light weight and excellent bending performance.

[0007] A first aspect of the present invention provides a 1100°C temperature-resistant flexible fireproof cable, comprising, arranged in order from the inside to the outside: a conductor (1), a conductor fireproof layer (2), a heat-insulating layer (4), a heat-insulating layer protective layer (5), and a metal layer (6); The conductor refractory layer (2) is formed by wrapping an inorganic mineral composite tape; The inorganic mineral composite tape uses inorganic silicate sodium silicate as a base material, and adds any one or more of the following materials as ceramic fillers: mica, kaolin, borate, glass powder, wollastonite, talc, bentonite, and aluminum hydroxide. The mass ratio of the base material to the ceramic filler is 100:75.

[0008] Furthermore, the conductor (1) is a compressed circular copper conductor.

[0009] Furthermore, the thermal insulation layer (4) is composed of a cable core and a high thermal insulation fireproof mud filled in the gap between the cable cores. The cable core is formed by twisting the wire core covered by the conductor fire-resistant layer (2) in a preset twisting direction. The high thermal insulation fireproof mud is formed by mixing high thermal insulation fireproof powder and glass glue in a ratio of 1:2 and then filling the gap between the cable cores by extrusion.

[0010] Furthermore, the heat-insulating protective layer (5) is formed by wrapping a high-silicon-oxygen high-temperature-resistant flame-retardant tape.

[0011] Furthermore, the metal layer (6) is a sheath welded from a nickel-copper alloy material, and the sheath is corrugated.

[0012] A second aspect of the present invention provides a method for producing a flexible fire-resistant cable with a temperature resistance of 1100° C., comprising the following steps: Prepare a round copper conductor (1) that is regularly stranded and compacted; Wrapping an inorganic mineral composite tape around the conductor to form a conductor fire-resistant layer (2); Twisting multiple wire cores into a cable core, and using high-insulation fireproof mud to squeeze and fill the gaps between the cable cores to form a thermal insulation layer (4); Wrapping a high-silicon-oxygen high-temperature-resistant flame-retardant tape around the thermal insulation layer (4) to form a thermal insulation layer protective layer (5); A corrugated nickel-copper alloy sheath is welded outside the heat-insulating protective layer (5) to form a metal layer (6).

[0013] Furthermore, the conductor (1) adopts a compact structure to maintain surface flatness.

[0014] Furthermore, the composite tape is prepared according to a mass ratio of substrate: ceramic filler = 100:75, the substrate is inorganic silicate sodium silicate, and the filler includes at least one or more of mica, kaolin, borate, glass powder, wollastonite, talc, bentonite and aluminum hydroxide.

[0015] Furthermore, the fireproof mud is uniformly mixed with high thermal insulation fireproof powder and glass glue in a mass ratio of 1:2.

[0016] Furthermore, the metal layer (6) is subjected to a laser micro-dissolution treatment after the rolling temperature treatment, so that a dense oxide layer is formed on the surface.

[0017] Compared with the prior art, the 1100°C temperature-resistant flexible fireproof cable and production method provided by the present invention have the following beneficial effects: (1) Considering that the fire resistance limit of traditional mica tape wrapped cables is insufficient and they are easy to pulverize and fall off at high temperatures of 1100°C, the present invention forms a conductor fire-resistant layer by using an inorganic sodium silicate base material and a ceramic filler in a specific ratio (100:75) as an inorganic mineral composite tape, forming a continuous ceramic body at 1100°C with a volume resistivity of ≥10 12 Ω·cm, tensile strength ≥5MPa, significantly improving the fire resistance limit to 1100℃ while maintaining insulation integrity.

[0018] (2) Due to the poor thermal insulation effect of conventional fireproof mud (the temperature difference between the inside and outside of the cable core is less than 300°C), the conductor will melt due to overheating in a fire. The high-insulation fireproof mud provided by the present invention (fireproof powder: glass glue = 1:2) is extruded and filled to form a porous thermal insulation structure (thermal conductivity ≤ 0.015W / (m·K)) at high temperature, achieving a temperature difference between the inside and outside of the cable core of ≥ 500°C, ensuring that the conductor temperature is ≤ 600°C when the external temperature is 1100°C.

[0019] (3) Mineral insulated cables (BTTZ type) have a large bending radius (10-15 times the cable diameter) due to their rigid sheath, which limits their application scenarios. The corrugated nickel-copper alloy sheath (corrugation depth 0.2-0.3 mm) provided by the present invention reduces the bending radius to 6 times the cable diameter. At the same time, laser micro-dissolution treatment forms a dense oxide layer, which improves the temperature resistance to 1200°C.

[0020] (4) The thermal expansion coefficients between traditional cable layers do not match and are directly connected, which easily leads to cracking. The high silica protective layer (thermal expansion coefficient 5.5×10 -6 / ℃) with nickel-copper sheath (13×10 -6 / ℃) is reduced to 7.5×10 -6 / ℃, combined with flexible fireproof mud buffer, it can avoid interface stress cracking, thus combining the advantages of traditional NH type cable and mineral insulated cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute a part of the present disclosure, are used to provide a further understanding of the present disclosure. The exemplary embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation to the present disclosure.

[0022] Figure 1This is a schematic structural diagram of a 1100°C temperature-resistant flexible fireproof cable provided in Example 1 of the present invention; In the figure, 1. conductor; 2. conductor fire-resistant layer; 3. insulation layer extrusion filling; 4. insulation layer; 5. insulation layer protective layer; 6. metal layer. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0025] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0026] Example 1 like Figure 1 The present invention provides a 1100°C temperature-resistant flexible fireproof cable, comprising: a conductor (1), a conductor fireproof layer (2), a heat-insulating layer (4), a heat-insulating layer protective layer (5), and a metal layer (6) arranged in sequence from the inside to the outside; The conductor refractory layer (2) is formed by wrapping an inorganic mineral composite tape; The inorganic mineral composite tape uses inorganic silicate sodium silicate as a base material, and adds any one or more of the following materials as ceramic fillers: mica, kaolin, borate, glass powder, wollastonite, talc, bentonite, and aluminum hydroxide. The mass ratio of the base material to the ceramic filler is 100:75.

[0027] The sodium silicate matrix (melting point 1088°C) is an inorganic binder that does not burn or release toxic gases at high temperatures. Among the ceramic fillers, mica (heat resistance 1200°C) provides a layered insulating structure, kaolin (melting point 1785°C) and wollastonite (melting point 1540°C) improve high-temperature strength, and borate (melting point 550°C) forms a glass phase at high temperatures, filling gaps and inhibiting crack propagation. The composite tape has a tensile strength of ≥15MPa at 25°C and still maintains a tensile strength of ≥5MPa at a high temperature of 1100°C, and its dielectric strength is ≥20kV / mm.

[0028] The conductor fire-resistant layer (2) serves as the innermost fire-resistant barrier, withstands the high temperature of the external flame, and prevents heat from being transferred to the conductor; maintains the electrical insulation between the cores, and ensures the integrity of the line under fire conditions; the thermal expansion coefficient of the inorganic components of the composite tape and the metal layer material (nickel-copper alloy) is about 13×10 -6 / ℃) is close to (the thermal expansion coefficient of the composite tape is 8×10 -6 / ℃), good material compatibility.

[0029] Specifically, the conductor (1) is a compacted circular copper conductor that complies with the provisions of GB / T3956-2008. The conductor is subjected to compaction treatment after being twisted in a regular manner, and the surface roughness Ra is ≤ 0.8 μm.

[0030] The compact structure ensures a smooth conductor surface, providing a foundation for the subsequent uniform wrapping of the conductor's fire-resistant layer and preventing the wrapping layer from being too thin locally due to surface protrusions. The circular cross-section reduces gaps when the cores are twisted, making it easier to fill the insulation layer. The copper conductor has excellent electrical conductivity (conductivity ≥ 98% IACS), ensuring the cable's current carrying capacity.

[0031] Specifically, the thermal insulation layer (4) is composed of a cable core and a high thermal insulation fireproof mud filled in the gap between the cable cores. The cable core is formed by twisting the wire core covered by the conductor fire-resistant layer (2) in a preset twisting direction. The high thermal insulation fireproof mud is a mixture of high thermal insulation fireproof powder and glass glue in a ratio of 1:2 and then filled in the gap between the cable cores by extrusion.

[0032] The main components of high-insulation fire-retardant powder are expanded vermiculite (volume expansion rate ≥200%) and silica aerogel (thermal conductivity coefficient ≤0.02W / (m•K)), and the glass glue is silicone (temperature resistance 250℃); fire-retardant mud is plastic at room temperature, and at high temperature (≥300℃), the glass glue carbonizes and the vermiculite expands to form a porous insulation layer, and the thermal conductivity coefficient drops below 0.015W / (m•K).

[0033] Extrusion filling ensures that the cable core gap is completely sealed to prevent direct flame intrusion; the porous structure formed under high temperature can effectively block heat conduction, making the internal temperature of the cable core ≤600℃ (when the external flame is 1100℃), achieving a temperature difference of ≥500℃, protecting the conductor and insulation layer; the flexible fireproof mud buffers the thermal expansion difference between the inner and outer layers, further reducing the interface stress.

[0034] Specifically, the heat insulation layer protective layer (5) is formed by wrapping a high-silicon-oxygen high-temperature resistant flame-retardant tape.

[0035] It is made of high-silica high-temperature resistant flame-retardant tape wrapped in the opposite direction of the cable core twisting direction (reverse wrapping), with an overlap rate of ≥25%; high-silica fiber content ≥96%, temperature resistance of 1100℃, and breaking strength ≥300MPa; it does not shrink or melt at high temperatures and maintains structural integrity.

[0036] The expansion direction of the fireproof mud of the thermal insulation layer is restricted at high temperatures to prevent the structure from becoming loose due to disordered expansion; it resists direct erosion of external flames and protects the thermal insulation layer from mechanical damage; the reverse wrapping design offsets the torque generated by the cable core twisting and improves the overall flexibility of the cable.

[0037] Specifically, the metal layer (6) is a sheath welded from a nickel-copper alloy material, and the sheath is corrugated.

[0038] The metal layer (6) is a sheath welded from a 1200°C temperature-resistant nickel-copper alloy (nickel content 20-25%), with a thickness of 0.3-0.5 mm and corrugated (corrugation depth 0.2-0.3 mm, pitch 2-3 mm).

[0039] The tensile strength of nickel-copper alloy is ≥200MPa at 1100℃, which is higher than that of pure copper (strength ≤50MPa at 1100℃); the corrugated structure reduces the bending stiffness of the sheath by 40-50%, and the bending radius can reach 6 times the diameter.

[0040] As the outermost fire barrier, it directly withstands the burning of 1100℃ flames and prevents flames and high-temperature gases from invading the interior; the corrugated design breaks the rigidity limitations of traditional metal sheaths, improving flexibility while ensuring high-temperature strength; the nickel-copper alloy has better oxidation resistance than pure copper, extending the effective working time in fire.

[0041] The 1100°C temperature-resistant flexible fireproof cable provided by the present invention complies with the following standards: (1) National Standard GB / T19216.21-2003 "Line integrity test for electrical or optical cables under flame conditions Part 21: Test procedures and requirements for cables with rated voltages of 0.6 / 1.0 kV and below". This method is equivalent to IEC60331-21:1999 and requires that the cable maintain its operating capacity under specified conditions under flame combustion conditions.

[0042] (2) British Standard BS 6387:2013, "Test method for resistance to fire of cables required to maintain circuit integrity under fire conditions," requires cables to maintain circuit integrity under fire conditions and is applicable to cables with an outer diameter of no more than 20 mm. Unlike GB / T19216, this method places greater emphasis on the environmental conditions of the cable under actual fire conditions. Therefore, in addition to fire alone, the test conditions also include circuit integrity criteria under conditions such as different flame temperatures, water spray, and mechanical impact.

[0043] (3) British Standard BS 8491:2008 “Method for assessment of fire integrity of large diameter power cables for use as components for smoke and heat control systems and certain other active fire safety systems” applies to cables with an outer diameter greater than 20 mm. The standard method is to supply fire to the cable and apply water spray and impact. The test categories are divided into 30 minutes, 60 minutes, and 120 minutes according to the fire exposure time.

[0044] Table 1 lists the test items, test temperature and test time of common fire-resistant cable fire resistance test methods.

[0045] Table 1 Comparison of common fire resistance test methods and standards

[0046] Common fire-resistant cable product standards in my country are shown in Table 2, all of which use the above test methods.

[0047] Table 2 Comparison of implementation standards and fire resistance test methods for common fire-resistant cables in my country

[0048] Due to the improvement of temperature resistance level, more complex insulation, fire-resistant materials and structures are required than ordinary fire-resistant cables. From the inside to the outside, it is usually composed of conductor, insulation layer, fire-resistant isolation layer (filling + wrapping / extrusion) sheath layer and other structures to meet the needs of electrical performance and fire resistance.

[0049] Currently, my country has relatively complete national and industry product standards for low-voltage fire-resistant cables. However, actual fire scene temperatures far exceed standard requirements. Therefore, raising the fire-resistant temperature of cables requires more standardized, scientific, and universal standards to improve product quality. The 1100°C temperature-resistant flexible fire-resistant cable provided by the present invention combines the flexibility of wrapped fire-resistant cables with the high-temperature resistance of mineral-insulated cables, offering excellent bending properties and the ability to withstand temperatures up to 1100°C.

[0050] Specifically, the technical characteristics and limitations of the mainstream wrapped fire-resistant cables and insulated mineral cables currently on the market are as follows: 1. Traditional wrapped fire-resistant cable (NH type) The core structure of traditional wrapped fire-resistant cable (NH type) is a mica tape wrapped around the conductor (such as the implementation standard GA306.2-2006), with a rated voltage of 0.6 / 1kV and below. Its technical features include: 1) Structurally: It consists of a conductor, a mica tape wrapping layer, an insulation layer, and a sheath layer, and relies on the high-temperature resistance of the mica tape to achieve fire resistance. 2) Advantages: simple structure, mature production technology, low cost, and certain flexibility, easy to lay; 3) Limitations: The fire resistance test temperature is only 750-950°C, which cannot cope with extreme fire environments exceeding 1000°C; mica tape is prone to falling off and cracking at high temperatures, especially under vibration or bending conditions, and the insulation performance between wire cores is prone to failure; it relies on the flame retardancy of the outer sheath. After the sheath burns in a fire, the mica tape is directly exposed to the flame, accelerating its failure.

[0051] 2. Mineral insulated cable (BTTZ / YTTW / RTTZ type) Mineral insulated cables use copper sheaths wrapped with inorganic mineral insulation materials (e.g., in accordance with GB / T13033.1-2007), with a rated voltage of 500V / 750V. Their technical features include: 1) Structurally: It consists of copper conductor, inorganic mineral insulation layer (such as magnesium oxide), and copper sheath. Some types (such as YTTW) use copper tape longitudinally wrapped welded sheath; 2) Advantages: Good temperature resistance, can withstand high temperatures of 950-1000℃; the insulation layer is inorganic and does not burn in fire, and has high insulation reliability.

[0052] 3) Limitations: Extremely poor flexibility, the rigid copper sheath results in a large bending radius of the cable (usually 10-15 times the diameter), which cannot adapt to the laying requirements of small spaces or complex paths; heavy weight, thick outer diameter, and thick copper sheath make the cable 30%-50% heavier than traditional cables, increasing the installation load; high cost, huge copper consumption, and complex welding process, the production cost is 2-3 times that of traditional cables; joint processing is difficult, and on-site joints require a special sealing process, otherwise they are easily affected by moisture, resulting in a decrease in insulation performance.

[0053] Although traditional wrapped fire-resistant cables and mineral insulated cables each have their own advantages, those skilled in the art do not directly combine the two cables for the following reasons: 1. Material compatibility conflict Thermal expansion coefficient mismatch: The thermal expansion coefficient of the mica tape (mainly silicate) of the traditional wrapped cable is about 5×10 -6 / ℃, while the thermal expansion coefficient of the copper sheath of the mineral insulated cable is 17×10 -6 / ℃, the difference between the two is more than 3 times. Under high temperature conditions (such as above 800℃), the thermal expansion difference will lead to interface stress concentration, causing cracking of the wrapping layer or deformation of the sheath, destroying the insulation and structural integrity; Chemical stability conflict: The inorganic mineral insulation materials (such as magnesium oxide) in mineral insulated cables are alkaline at high temperatures, while the mica tapes of traditional wrapped cables contain a small amount of organic binders (such as phenolic resin). At high temperatures, they decompose to produce acidic gases, which react chemically with alkaline minerals, causing the insulation layer to deteriorate and fail. Contradiction in mechanical properties: The mica tape has a layered structure and low shear strength (about 20 MPa), while the copper sheath has high rigidity (elastic modulus 110 GPa). Under bending or impact conditions, the deformation of the sheath will directly shear and destroy the mica tape wrapping, resulting in loss of fire resistance.

[0054] 2. Structural design contradictions The conflict between flexibility and rigidity: Traditional wrapped cables rely on the stacking of wrapping layers to achieve flexibility, while the rigid sheath of mineral insulated cables ensures their heat resistance and structural strength. The two structural principles are completely contradictory. If the mica tape wrapping layer is simply placed inside the copper sheath, the rigidity of the sheath will completely suppress the flexibility advantage of the wrapping layer, resulting in a cable with no flexibility and increased outer diameter and weight due to the wrapping layer. Redundancy and loss of insulation function coexist: the inorganic mineral layer of the mineral insulated cable already has insulation function. If a mica tape wrapping layer is superimposed, the thickness of the insulation layer will increase (redundancy). However, air gaps may form at the interface between the two at high temperatures, which will reduce the insulation reliability. Conversely, if mica tape is used to replace the mineral insulation layer, the temperature resistance level of the mineral insulated cable cannot be achieved (loss).

[0055] 3. Process feasibility barriers Production process conflicts: The wrapping process of traditional wrapped cables (such as concentric layer wrapping) requires the base material to have a certain degree of ductility, while the sheath welding process of mineral insulated cables (such as argon arc welding) requires high temperature heating (about 1100°C), which will cause the organic binder in the mica tape to carbonize and destroy the wrapping layer structure; Difficulty in dimensional control: The copper sheath requires high welding accuracy (error must be ≤0.1mm), while the thickness uniformity of the sheath is poor (error is usually ±0.2mm). The combination of the two will lead to uneven stress distribution inside the sheath, which is prone to local rupture at high temperatures.

[0056] 4. Performance balance problem Imbalance between heat resistance and flexibility: If the copper sheath is retained to ensure heat resistance, flexibility must be sacrificed; if the sheath is thinned to improve flexibility, the sheath will collapse due to insufficient strength at high temperatures (≥900°C), losing protection for the internal cladding; Imbalance between cost and benefit: Combining the two structures means bearing the material costs of both the winding layer and the metal sheath, resulting in cable prices far exceeding market acceptance, while the performance improvement (such as a temperature resistance increase of only 50-100°C) is not proportional to the cost increase.

[0057] The 1100°C temperature-resistant flexible fireproof cable provided by the present invention solves the difficulties in combining traditional wrapped cables with mineral insulated cables through the following technical features: 1. Select materials with matching thermal expansion coefficients: the conductor refractory layer is made of sodium silicate-ceramic composite tape (thermal expansion coefficient 8×10 -6 / ℃), with nickel-copper alloy sheath (13×10 -6 / ℃) is controlled within 5×10 -6 / ℃ (the difference between traditional copper sheath and mica tape is 12×10 -6 / ℃), significantly reducing interface stress; the flexible buffer of the fireproof mud in the insulation layer further absorbs the thermal expansion difference and avoids cracking.

[0058] 2. The conductor fire-resistant layer adopts all-inorganic components (sodium silicate + ceramic filler), which has no chemical reaction with the high-silica protective layer and nickel-copper alloy; the glass glue in the fireproof mud is completely carbonized at high temperature (no residual organic matter), avoiding acid-base reaction with inorganic materials.

[0059] 3. Metal layer corrugation design: The corrugated structure of the nickel-copper alloy sheath forms a "flexible hinge", allowing the sheath to bend freely along the corrugation direction, with a bending radius reduced to 6 times the diameter (traditional copper sheaths require 10-15 times); the addition of nickel ensures that the alloy maintains sufficient strength at 1100°C, solving the problem of insufficient strength caused by thinning the sheath. Specifically, the strength of a 0.3mm nickel-copper alloy sheath at 1100°C is equivalent to that of a 1mm pure copper sheath.

[0060] The reverse wrapped thermal insulation layer is twisted in the opposite direction to the cable core to offset the internal stress; each layer adopts a wrapped or filled structure (non-rigid extrusion) to reserve a certain deformation space.

[0061] Example 2 The present invention provides a method for producing a flexible fireproof cable with a temperature resistance of 1100°C, comprising the following steps: Prepare a round copper conductor (1) that is regularly stranded and compacted; Wrapping an inorganic mineral composite tape around the conductor to form a conductor fire-resistant layer (2); Twisting multiple wire cores into a cable core, and using high-insulation fireproof mud to squeeze and fill the gaps between the cable cores to form a thermal insulation layer (4); Wrapping a high-silicon-oxygen high-temperature-resistant flame-retardant tape around the thermal insulation layer (4) to form a thermal insulation layer protective layer (5); A corrugated nickel-copper alloy sheath is welded outside the heat-insulating protective layer (5) to form a metal layer (6).

[0062] Specifically, the conductor (1) adopts a compact structure to maintain surface flatness.

[0063] Specifically, the composite tape is prepared according to a mass ratio of substrate to ceramic filler = 100:75, the substrate is inorganic silicate sodium silicate, and the filler includes at least one or more of mica, kaolin, borate, glass powder, wollastonite, talc, bentonite and aluminum hydroxide.

[0064] Specifically, the fireproof mud is prepared by uniformly mixing high thermal insulation fireproof powder and glass glue in a mass ratio of 1:2.

[0065] Specifically, the metal layer (6) is subjected to a rolling temperature treatment and then a laser micro-dissolution treatment, so that a dense oxide layer is formed on the surface.

[0066] In a specific embodiment, the production method comprises the following steps: S1: Preparation of conductor (1) Electrolytic copper rods with a purity of ≥99.95% are selected and drawn into copper single wires with a diameter of 0.2-2.5mm by a wire drawing machine; The copper single wires are twisted into a conductor core according to the twisting method (regular twisting) specified in GB / T3956-2008, and the twisting pitch is 16-20 times the conductor diameter; The stranded conductor is compacted using a continuous compaction die (compression rate 20-25%) to ensure that the conductor surface roundness is ≤0.05mm and the roughness Ra is ≤0.8μm.

[0067] S2: Fire-resistant layer around the conductor (2) An inorganic mineral composite tape was prepared in a ratio of (base material: filler = 100:75): sodium silicate solution (concentration 40-45%) was mixed with a ceramic filler (mica 30%, kaolin 20%, borate 15%, glass powder 10%, wollastonite 10%, talc 5%, bentonite 5%, aluminum hydroxide 5%), and coated onto a glass fiber base cloth (thickness 0.1 mm) using a tape casting machine. The tape was then dried at 120°C for 2 hours to produce a composite tape with a thickness of 0.2-0.3 mm. A double-station wrapping machine (wrapping speed 30-50m / min) is used to wrap the composite tape around the conductor. The wrapping tension is controlled at 5-8N to ensure that the tape fits tightly to the conductor surface with an overlap rate of 30%.

[0068] S3: Forming a thermal insulation layer (4) The wire cores obtained in step S2 are twisted into a cable core in a preset direction (left direction), with a twisting pitch of 10-12 times the wire core diameter and a uniform twisting tension (error ≤±5%); Prepare high-insulation fireproof mud: Add high-insulation fireproof powder (60% expanded vermiculite, 40% silica aerogel) and silicone glass glue in a ratio of 1:2 into a stirring kettle and stir at a speed of 500-800 rpm for 15-20 minutes until the mixture becomes a uniform paste; Use an extrusion filling machine (pressure 0.5-0.8MPa) to inject the fireproof mud into the cable core gap. The filling speed should match the twisting speed (synchronous control) to ensure that the gap is completely filled without bubbles.

[0069] S4: Wrapped insulation layer protective layer (5) Use high-silicon-oxygen high-temperature resistant flame-retardant tape (width 10-20mm, thickness 0.1-0.2mm) and wrap it around the insulation layer through a reverse wrapping machine (opposite to the twisting direction of the cable core, i.e. right direction); The wrapping tension is controlled at 3-5N and the overlap rate is 25% to ensure that the strip is flat and wrinkle-free.

[0070] S5: Preparation of metal layer (6) A nickel-copper alloy strip (0.3-0.5mm thick) with a nickel content of 20-25% is selected and pre-bent into a U-shaped groove by a forming die; Insert the cable core obtained in step S4 into the U-shaped groove and weld the seam using a high-frequency induction welder (frequency 300-400kHz). The welding speed is synchronized with the production line (30-50m / min). The weld strength is ≥150MPa. The welded sheath is processed by a corrugating machine (corrugation depth 0.2-0.3mm, pitch 2-3mm), with a corrugating pressure of 10-15MPa to ensure uniform corrugation and no cracks on the sheath; After embossing, laser micro-dissolution treatment is performed (power 1000-1500W, scanning speed 100-200mm / s) to form a dense oxide layer with a thickness of 5-10μm (main components are NiO and CuO) on the surface of the sheath to improve the anti-oxidation performance.

[0071] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

[0072] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A flexible fireproof cable with a temperature resistance of 1100°C, characterized in that: It comprises, arranged in order from the inside out: a conductor (1), a conductor fire-resistant layer (2), a heat-insulating layer (4), a heat-insulating layer protective layer (5), and a metal layer (6); The conductor refractory layer (2) is formed by wrapping an inorganic mineral composite tape; The inorganic mineral composite tape uses inorganic silicate sodium silicate as a base material, and adds any one or more of the following materials as ceramic fillers: mica, kaolin, borate, glass powder, wollastonite, talc, bentonite, and aluminum hydroxide. The mass ratio of the base material to the ceramic filler is 100:

75.

2. The 1100°C temperature-resistant flexible fireproof cable according to claim 1, characterized in that: The conductor (1) is a compressed circular copper conductor.

3. The 1100°C temperature-resistant flexible fireproof cable according to claim 1, characterized in that: The thermal insulation layer (4) is composed of a cable core and a high thermal insulation fireproof mud filled in the gap between the cable cores. The cable core is formed by twisting the wire core covered by the conductor fireproof layer (2) in a preset twisting direction. The high thermal insulation fireproof mud is a mixture of high thermal insulation fireproof powder and glass glue in a ratio of 1:2 and then filled in the gap between the cable cores by extrusion.

4. The 1100°C temperature-resistant flexible fireproof cable according to claim 1, characterized in that: The heat insulation layer protective layer (5) is formed by wrapping a high-silicon-oxygen high-temperature resistant flame-retardant tape.

5. The 1100°C temperature-resistant flexible fireproof cable according to claim 1, characterized in that: The metal layer (6) is a sheath welded from a nickel-copper alloy material, and the sheath is corrugated.

6. The method for producing a 1100°C temperature-resistant flexible fireproof cable according to any one of claims 1 to 5, characterized in that: The steps include: Prepare a round copper conductor (1) that is regularly stranded and compacted; Wrapping an inorganic mineral composite tape around the conductor to form a conductor fire-resistant layer (2); Twisting multiple wire cores into a cable core, and using high-insulation fireproof mud to squeeze and fill the gaps between the cable cores to form a thermal insulation layer (4); Wrapping a high-silicon-oxygen high-temperature-resistant flame-retardant tape around the thermal insulation layer (4) to form a thermal insulation layer protective layer (5); A corrugated nickel-copper alloy sheath is welded outside the heat-insulating protective layer (5) to form a metal layer (6).

7. The production method according to claim 6, characterized in that The conductor (1) adopts a compact structure to maintain surface flatness.

8. The production method according to claim 6, characterized in that The composite tape is prepared according to a mass ratio of base material to ceramic filler of 100:75, wherein the base material is inorganic sodium silicate, and the filler comprises at least one or more of mica, kaolin, borate, glass powder, wollastonite, talc, bentonite and aluminum hydroxide.

9. The production method according to claim 6, wherein The fireproof mud is prepared by uniformly mixing high heat-insulating fireproof powder and glass glue in a mass ratio of 1:

2.

10. The production method according to claim 6, characterized in that The metal layer (6) is subjected to a laser micro-dissolution treatment after being subjected to a rolling temperature treatment, so that a dense oxide layer is formed on the surface.

Images