Production method of high-structural-strength insulated steel tape armored multi-core power cable

Abstract

The invention discloses a production method of a high-structural-strength insulating steel tape armored multi-core power cable. The power cable comprises a conductor unit and an insulating layer from inside to outside, wherein the conductor unit is formed by twisting and pressing a conductor with a copper base material, the conductor unit is wrapped outside the conductor, the overlapping rate of the conductor unit is larger than or equal to 50%, and the insulating layer is formed by semi-conductive ceramic silicone rubber and / or crosslinked polyethylene. The double-layer wrapping tape is composed of ceramic silicone rubber filling strips and assists the insulating core wires to be twisted into a cable and is of a filling structure; an inner sheath made of a ceramic silicone rubber material; the composite armor layer is composed of an inner-layer galvanized steel band and an outer-layer stainless steel band; the buffer layer is composed of an aramid fiber woven mesh or a ceramic fiber belt; and the outer sheath is composed of ceramic silicone rubber or a low-smoke halogen-free flame-retardant material of which the oxygen index is greater than or equal to 40. The cable is high in structural strength, good in temperature resistance and high in impact resistance, high-temperature mechanical locking is achieved through tension-controlled double-layer reverse wrapping, and the performance of the cable is greatly improved.

Description

TECHNICAL FIELD

[0001] The application relates to a high-structural-strength insulated steel-tape armored multi-core power cable production method. BACKGROUND

[0002] A cable is a wire harness composed of one or more insulated conductors wrapped in a common sheath, and the core function is to transmit electric energy or electrical signals; the existing cable has the following deficiencies in the use process: 1. poor fire resistance: the traditional mica tape wrapping process has a low coverage rate (<30%), and the mica tape is easy to fall off in a fire; the polyethylene sheath melts and drips, accelerating the spread of the fire; 2. mechanical strength limitation: single-layer galvanized steel tape armor is easy to deform under impact, and the high-temperature strength attenuation is greater than 60%; 3. protection is split: the fire-resistant layer and the mechanical protection layer are independent of each other, and the expansion and extrusion of the armor in a fire cause short circuits. In view of the many deficiencies of the existing cable, it is necessary to develop a high-structural-strength insulated steel-tape armored multi-core power cable and a production method. SUMMARY

[0003] The technical problem to be solved by the application is to provide a high-structural-strength insulated steel-tape armored multi-core power cable production method which has high structural strength, good temperature resistance, strong impact resistance, a double-layer reverse wrapping setting controlled by tension, realizes high-temperature mechanical locking, replaces 50% of the amount of mica tape with ceramicized silicone rubber, reduces the material cost by 22%, reduces the amount of steel wire in the composite armor, and reduces the weight of the cable by 18%; and a three-section water temperature control combined with an embossing die improves the environmental adaptability of the sheath.

[0004] To solve the above problems, the application adopts the following technical scheme: A high-structural-strength insulated steel-tape armored multi-core power cable comprises, from the inside to the outside: A conductor unit composed of a copper-based material twisted and compressed conductor and a double-layer fire-resistant layer wrapped outside the conductor with a coverage rate of greater than or equal to 50%, wherein the double-layer fire-resistant layer is composed of an inner layer of mica tape and an outer layer of synthetic mica tape; An insulation layer composed of semi-conductive ceramicized silicone rubber and / or cross-linked polyethylene and extruded outside the fire-resistant layer, wherein the insulation layer comprises an inner layer of conductor shielding layer, a middle layer of insulation layer and an outer layer of insulation shielding layer; A filling structure composed of ceramicized silicone rubber filling strips and assisting in twisting the insulated core into a cable, and a double-layer wrapping tape composed of an inner layer of alkali-free glass fiber tape with a wrapping overlap rate of greater than or equal to 30% and an outer layer of synthetic mica tape and extruded outside the insulated core and the filling structure; An inner sheath composed of ceramicized silicone rubber material and extruded outside the double-layer wrapping tape; A composite armor layer composed of an inner layer of galvanized steel tape and an outer layer of stainless steel tape and wrapped outside the inner sheath; The buffer layer is composed of aramid fiber woven net or ceramic fiber tape and is coated outside the composite armor layer; The outer sheath is composed of ceramicized silicone rubber or low-smoke halogen-free flame retardant material with an oxygen index of ≥40 and is extruded outside the buffer layer.

[0005] Preferably, the material of the inner conductor shielding layer and the outer insulating shielding layer is semi-conductive ceramicized silicone rubber with 15% conductive carbon black added, and the viscosity index is 1.2×10 4 Pa·s, the resistivity is reduced by increasing the conductive network through conductive carbon black.

[0006] The ceramic conversion temperature threshold of the semi-conductive ceramicized silicone rubber is 550℃±20℃, and the high-temperature residual strength is ≥15MPa.

[0007] The material of the middle insulating layer is cross-linked polyethylene with 40% ceramic filler mixed in, and the ceramic filler is vitrified microsphere + calcined kaolin.

[0008] Preferably, the thickness of the inner galvanized steel tape in the composite armor layer is 0.5mm±0.05mm, and the thickness of the outer stainless steel tape is 0.2mm±0.02mm, and the stainless steel tape is reversely wrapped to achieve full coverage. The wrapping gap rate of the galvanized steel tape is ≤40%, the wrapping angle is 28°±2°, and the mass of the galvanized layer is ≥140g / m²; a preset deformation allowance is provided, and the time gap is closed under pressure to form a continuous protective layer.

[0009] The reverse wrapping angle of the stainless steel tape is 32°±2°; the reverse wrapping compensates for internal stress, and the strength retention rate at high temperature is >80%.

[0010] The gap misorientation angle between the galvanized steel tape and the stainless steel tape is ≥45°.

[0011] The galvanized steel tape and the stainless steel tape are coated with a heat-expanding adhesive with a coating amount of 8g / m², which expands the gap in a fire and forms a ceramic sealing body.

[0012] Preferably, the surface of the outer sheath is provided with anti-abrasion corrugated lines with a corrugation depth of 0.3-0.5mm and a pitch of 5-8mm.

[0013] A production method for making a high-structural-strength insulated steel-tape armored multi-core power cable, comprising the following steps: S1. Perform conductor unit pretreatment, specifically: perform die drawing and coating treatment on the copper base material; S2. Use a screw extruder to synchronously extrude three layers of insulation: extrusion pressure: 25±2MPa, extrusion speed: 6-8m / min; S3. Perform insulation core cable formation operation: S4. Extruding inner sheath: extruding ceramicized silicone rubber material by vacuum sizing extrusion die, and then cooling to form inner sheath; S5. Performing composite armor layer wrapping: front and rear gap wrapping of galvanized steel belt and full coverage wrapping of stainless steel belt are performed; S6. Performing buffer layer wrapping: aramid fiber woven mesh or ceramic fiber tape wrapping operation is performed on the outer side of the composite armor; S7. Performing outer sheath extrusion operation: ceramicized silicone rubber or low-smoke halogen-free flame-retardant material is extruded by screw machine, and then cooled to form outer sheath.

[0014] Preferably, the conductor unit pretreatment step in step S1 is: 1) The copper base material is drawn to a set diameter through eight dies; 2) The drawn copper base material is annealed under nitrogen protection at a temperature of 450℃±5℃ and is kept for 120s; the cooling rate after annealing is 10℃ / s; hardening is eliminated and conductivity is improved; 3) The copper base material is stranded into a tight circular conductor by a 24-disc stranding machine; 4) Double-layer fire-resistant layer is wrapped by a double-head synchronous wrapping machine, specifically: the inner layer of mica tape is wrapped at an angle of 52°±3°, and the outer layer of synthetic mica tape is wrapped at an angle of 48°±3°; the double-angle difference forms mechanical interlocking.

[0015] Preferably, the mica tape is preheated to 60℃ to soften the adhesive during inner layer wrapping; the synthetic mica tape is synchronously sprayed with silane coupling agent with a concentration of 5wt% during outer layer wrapping.

[0016] The overlap joint position of the mica tape and the synthetic mica tape is offset by an angle of ≥90°, and is heat-pressed by an infrared heat-pressing roller to cure and bond, with a heat-pressing temperature of 80℃±5℃ and a pressure of 0.3MPa; the overlap joint is offset to avoid heat channels.

[0017] Preferably, the screw extruder in step S2 uses a clothes hanger type split die head to extrude the inner conductor shielding layer, the middle insulating layer, and the outer insulating shielding layer; after the insulating layer is extruded, cross-linking is completed in a nitrogen protection vulcanization channel, with a nitrogen purity of ≥99.99% and a flow rate of 10L / min; the vulcanization time is the thickness of the insulating layer×1.2min / mm, and finally an insulating core wire is formed.

[0018] Preferably, the cable forming operation step of the insulating core wire in step S3 is as follows: 1) The insulating core wire S is stranded by a planetary cable machine at 17 times the cable diameter±5%; 2) Filling ceramicized silicone rubber strips simultaneously; 3) Double-layer wrapping tape: wrapping no-alkali glass fiber tape inside and synthetic mica tape outside.

[0019] Preferably, the aramid fiber woven net or ceramic fiber tape woven density in step S6 is ≥ 16 spindles / inch, and the tensile strength is ≥ 2800 MPa.

[0020] Meanwhile, the aramid fiber woven net adopts three-dimensional weaving technology, and the weaving angle is dynamically adjusted according to the formula:

[0021] Wherein, θ is the angle, R is the cable radius, N is the number of spindles, d is the yarn diameter, and P is the pitch; After weaving, the weaving nodes are impregnated with silicone resin, and after heat curing, elastic hinge points are formed.

[0022] The ceramic fiber tape material is Al2O3-SiO2 fiber, and the number of wrapping layers is 2, and the overlap rate is 50±5%.

[0023] Preferably, when the outer sheath material of step S7 adopts ceramic silicone rubber: add 5% nano silicon carbide as a heat-conducting reinforcing agent; immediately enter the step temperature control vulcanization box after extrusion by the screw machine: then perform three-stage gradient cooling; set the quenching tank, the main cooling tank and the final cooling tank; In this process, the gradient cooling thermodynamics is controlled, and the Fourier equation of the cooling process is established:

[0024] represent the temperature, is the time, , is the spatial coordinate, is the thermal diffusivity, wherein the thermal diffusivity α=1.2×10⁻ 7 m² / s; In this process, the final cooling tank adopts a vortex tube cooling, the cooling efficiency is improved by 40%, and the surface temperature of the cable after cooling is ≤ 35℃.

[0025] The beneficial effects of the present application are: 1. Fire-resistant-mechanical synergistic strengthening mechanism; mica tape-ceramic silicone rubber interface reaction: K⁺ ions released by the mica tape and SiO2 in the silicone rubber form kalsilite (KAlSiO4) at high temperature, so that the bending strength of the ceramic layer is increased to 18.5 MPa (compared with 12.3 MPa of a single ceramic layer), and the insulation layer and the sheath form a continuous ceramic hard shell (conversion temperature 550℃) when exposed to fire.

[0026] 2. Armoring tension matching design: the difference in elastic modulus between the stainless steel belt and the galvanized steel belt is compensated by tension, so that the radial deformation rate of the armoring layer at high temperature (800℃) is ≤ 3%; and high-temperature mechanical locking is realized through the double-layer reverse wrapping controlled by tension.

[0027] 3. Disaster environment adaptability improvement; Anti-detonation impact: Aramid buffer layer absorbs impact energy > 15J / cm³, 200% higher than traditional hemp rope filling (<5J / cm³), and aramid buffer layer and outer sheath corrugated structure improve dynamic environmental adaptability.

[0028] 4. Production cost optimization; 50% mica tape replaced by ceramicized silicone rubber, material cost reduced by 22%; composite armor reduces steel wire usage, cable weight reduced by 18%.

[0029] 5. Conductor-mica tape composite structure: double-layer mica tape large-angle wrapping provides a basic fire-resistant barrier.

[0030] 6. Gradient cooling embossing process: three-stage water temperature control combined with embossing die improves sheath environmental adaptability.

[0031] 7. By preheating to soften the adhesive (60℃) and silane coupling agent spraying, the interlayer peeling strength of mica tape is increased from 0.8N / mm to 2.3N / mm (actual value), solving the problem of delamination at high temperature. Double tape angle difference design (inner layer 52°→ outer layer 48°) forms a mechanical interlocking structure.

[0032] 8. Thermal expansion glue expands by 120% at 500℃, filling the gap between steel belts to form a ceramic seal (Mohs hardness 6.5), explosion shock wave attenuation rate: attenuation coefficient β = 0.25cm⁻¹ (traditional armor β = 0.12cm⁻¹), anti-blast pressure increased by 108%. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, a brief introduction to the drawings needed to be used in the embodiments or prior art description will be given below, but it is not a limitation on the protection scope of the present application.

[0034] Fig. 1 The process flow diagram of the present application is shown in the figure; Fig. 2 The cable structure diagram of the present application is shown in the figure.

[0035] Among them, 1. Copper base material, 2. Double-layer fire-resistant layer, 3. Insulating layer, 4. Filling structure, 5. Double-layer wrapping tape, 6. Inner sheath, 7. Composite armor layer, 8. Buffer layer, 9. Outer sheath, 10. Insulated core wire. DETAILED DESCRIPTION

[0036] As shown in the figure Figs. 1-2 A high structural strength insulated steel armored multi-core power cable, from inside to outside, includes: a conductor unit composed of a copper base material 1 tightly twisted conductor and a double-layer fire-resistant layer 2 wrapped outside the conductor with a coverage rate ≥ 50%, the double-layer fire-resistant layer is composed of an inner layer phlogopite mica tape and an outer layer synthetic mica tape; Insulating layer 3 composed of semi-conductive ceramic silicone rubber and / or cross-linked polyethylene, and extruded outside the fire-resistant layer; Filler structure 4 composed of ceramic silicone rubber filler strips, and auxiliary insulating core wire 10 twisted into a cable, and double-layered wrapping tape 5 composed of inner layer of overlapping rate ≥30% of alkali-free glass fiber tape and outer layer of synthetic mica tape, and extruded outside the insulating core wire and the filler structure; Inner sheath 6 composed of ceramic silicone rubber material, and extruded outside the double-layered wrapping tape; Composite armored layer 7 composed of inner layer of galvanized steel tape and outer layer of stainless steel tape, and coated outside the inner sheath; Buffer layer 8 composed of aramid fiber woven mesh or ceramic fiber tape, and coated outside the composite armored layer; Outer sheath 9 composed of ceramic silicone rubber or low-smoke halogen-free flame retardant material with oxygen index ≥40, and extruded outside the buffer layer.

[0037] Further, the material of the inner conductor shielding layer and the outer insulating shielding layer is semi-conductive ceramic silicone rubber, and 15% conductive carbon black (particle size 30 nm) is added to the semi-conductive ceramic silicone rubber, with viscosity index 1.2×10 4 Pa·s; the ceramic conversion temperature threshold of the semi-conductive ceramic silicone rubber is 550℃±20℃, and the high-temperature residual strength is ≥15MPa; The material of the middle insulating layer is cross-linked polyethylene, and 40% ceramic filler (vitrified small balls + calcined kaolin) is mixed into the cross-linked polyethylene, with Mooney viscosity ML(1+4)125°C=65.

[0038] Further, the cross-sectional area of the ceramic silicone rubber filler strip matches the cable core clearance rate ≥95%.

[0039] Further, the parameters of the composite armored layer are: The thickness of the inner galvanized steel tape is 0.5mm±0.05mm; The thickness of the outer stainless steel tape is 0.2mm±0.02mm, and the stainless steel tape is reversely wrapped to achieve full coverage.

[0040] Further, the weaving density of the aramid fiber woven mesh or ceramic fiber tape is ≥16 spindles / inch, and the tensile strength is ≥2800MPa.

[0041] Further, the outer sheath is provided with anti-abrasion corrugated lines on the surface, with corrugation depth 0.3-0.5mm and pitch 5-8mm.

[0042] Further, when the buffer layer is coated, an active pay-off weaving machine is used to coat the aramid fiber mesh or ceramic fiber tape; A production method for manufacturing high-structural-strength insulated steel-tape armored multi-core power cable, comprising the following steps: S1. Preprocessing the conductor unit, specifically, drawing the copper base material and coating treatment; S2. Using a screw extruder to synchronously extrude three layers of insulation layer: extrusion pressure: 25±2 MPa, extrusion speed: 6-8 m / min; S3. Insulated core cable operation; S4. Extruding the inner sheath: using a vacuum sizing extrusion die to extrude the ceramicized silicone rubber material, and then cooling to form the inner sheath; S5. Composite armored layer wrapping: front and rear gap wrapping of galvanized steel tape and full coverage wrapping of stainless steel tape operation; S6. Buffer layer coating: aramid fiber woven mesh or ceramic fiber tape coating operation on the outer side of the composite armor; S7. Outer sheath extrusion operation: extruding ceramicized silicone rubber or low-smoke halogen-free flame-retardant material base material through a screw machine, and then cooling to form an outer sheath.

[0043] Further, the conductor unit preprocessing step in step S1 is: 1) The copper base material is drawn to a set diameter through eight drawing dies; 2) The drawn copper base material is annealed under nitrogen protection, the temperature is: 450℃±5℃, and the temperature is kept for 120s; the cooling rate after annealing is 10℃ / s; 3) The copper base material is twisted into a tight circular conductor by a 24-die twisting machine; 4) Double-layer fire-resistant layer is coated by a double-end synchronous wrapping machine, specifically: The inner layer of mica tape is wrapped at an angle of 52°±3°, with a tension of 12-15 N; The outer layer of synthetic mica tape is wrapped at an angle of 48°±3°, with a tension of 8-10 N.

[0044] Further, the double-end synchronous wrapping machine is equipped with a laser centering system, with an offset of ≤0.1 m and a dynamic tension feedback accuracy of ±0.5 N; The gold mica tape is preheated to 60℃ to soften the adhesive during inner layer wrapping; The synthetic mica tape is synchronously sprayed with silane coupling agent at a concentration of 5wt% during outer layer wrapping; The overlap joint position of the gold mica tape and the synthetic mica tape is offset by an angle of ≥90°, and is heat pressed and cured by an infrared heat roller, with a heat pressing temperature of 80℃±5℃ and a pressure of 0.3 MPa.

[0045] Further, the step S2 screw extruder adopts clothes hanger type split die, and the inner conductor shielding layer, the middle insulating layer and the outer insulating shielding layer are extruded. After the insulating layer is extruded, cross-linking is completed in a nitrogen protection vulcanization channel (nitrogen purity ≥ 99.99%, flow rate 10 L / min), and the vulcanization time is: insulating layer thickness × 1.2 min / mm.

[0046] The three-layer insulating layer is: The inner conductor shielding layer is semi-conductive ceramicized silicone rubber, 15% conductive carbon black (particle size 30 nm) is added, and the viscosity index is 1.2 × 10 4 Pa·s; The middle insulating layer is: the base material is cross-linked polyethylene, 40% ceramicized filler is mixed, the ceramicized filler is vitrified small ball + calcined kaolin, and the Mooney viscosity ML(1+4) 125°C = 65; (1+4) means preheating for 1 minute and testing for 4 minutes, and the testing temperature is 125°C.

[0047] The outer insulating shielding layer is: the base material is semi-conductive ceramicized silicone rubber; The screw extruder adopts clothes hanger type split die, and the flow channel pressure loss is ≤ 8%, and the shear rate control ring (gradient 800-1200 s⁻¹) is arranged in the die lip area; At the same time, the screw extruder adopts online laser diameter measuring instrument for real-time monitoring, so that the insulating layer thickness deviation is ≤ ± 0.03 mm.

[0048] Further, the step S3 insulating core wire cabling operation step is as follows: 1) The planetary cabling machine is used to twist the insulating core wire S at 17 times the cable diameter ± 5%; and the ground core wire diameter is increased by 15%; 2) At the same time, the ceramicized silicone rubber strip is filled; the Shore hardness A is 60 ± 5, and the linear expansion coefficient is ≤ 5 × 10⁻ 6 / K; 3) Double-layer wrapping tape is performed: the inner layer is wrapped with alkali-free glass fiber tape, and the outer layer is wrapped with synthetic mica tape; The inner layer is: the alkali-free glass fiber tape, and the wrapping overlap rate is ≥ 30%; The outer layer is: the synthetic mica tape, and the wrapping tension is 5 ± 0.5 N.

[0049] In the implementation process, the planetary cabling machine twisting cage rotation speed and traction speed ratio meet:

[0050] Wherein is the cable diameter is the rotation speed (rpm), and α = 19° ± 1° is the entry angle; At the same time, the wrapping tape pre-tension closed-loop control is performed: the alkali-free glass fiber tape tension is 4.8 N ± 0.2 N, and the synthetic mica tape tension is 5.2 N ± 0.2 N.

[0051] Further, the water layer thickness is 0.1 mm, the flow rate is 2 m / s, and the cooling gradient is ≤3 ℃ / mm in the step S4.

[0052] Further, the gap rate of the galvanized steel belt is ≤40%, the wrapping angle is 28°±2°, and the tension is 85±5 N in the step 5. The wrapping angle of the stainless steel belt is reversely 32°±2°, and the tension is 70±3 N. The gap misalignment angle between the galvanized steel belt and the stainless steel belt is ≥45°. The yield strength of the galvanized steel belt is ≥350 MPa, and the wrapping curvature radius R is 6D, where D is the cable diameter. The galvanized steel belt is pre-bent into an arc shape, and the curvature radius R is 5D, which releases the internal stress of the wrapping. The galvanized steel belt and the stainless steel belt are coated with a thermal expansion adhesive, the coating amount is 8 g / m², the viscosity at 23 ℃ is 5000 cP, the expansion rate at 500 ℃ is 120%, the ceramic sealing body is formed by filling the gap between the steel belts, and the explosion shock wave attenuation rate is:

[0053] wherein, is the changed pressure, is the initial pressure, is the attenuation coefficient, β=0.25 cm⁻¹ (β=0.12 cm⁻¹ for traditional armoring), is the variable affecting the pressure attenuation.

[0054] Further, the aramid fiber woven net in the step S6 adopts a three-dimensional weaving technology, and the weaving angle is dynamically adjusted according to the formula:

[0055] wherein R is the cable radius, N is the number of spindles, d is the yarn diameter, and P is the pitch; The tension of each spindle is controlled in real time, and the fluctuation is ≤±0.3 N; Meanwhile, the nodes during weaving are impregnated with silicon resin, the solid content is 40%, and the elastic hinge points are formed after thermal curing; The ceramic fiber belt material is Al2O3-SiO2 fiber, and the wrapping layer number is 2, and the overlap rate is 50±5%.

[0056] Further, when the outer sheath material in the step S7 is ceramicized silicone rubber, 5% of nano silicon carbide (particle size 50 nm) is added as a heat conduction enhancer; after extrusion by a screw machine, it immediately enters a step temperature control vulcanization box: the specific data are as follows in Table 1. Table 1 After that, three-stage gradient cooling is carried out; the quenching tank, the main cooling tank and the final cooling tank are arranged; the turbulent flow generator is arranged in the quenching tank; the vortex tube cooling (the gas temperature is-15 DEG C) is adopted in the final cooling tank, and the cooling efficiency is increased by 40%. The three-stage gradient cooling details are shown in the following table 2: Table 2 After cooling, the surface temperature of the cable is less than or equal to 35 DEG C.

[0057] In the implementation process, the gradient cooling thermodynamic control is established, and the Fourier equation of the cooling process is established:

[0058] Wherein, represents the temperature, is time, , is a spatial coordinate, is a thermal diffusion coefficient, wherein the thermal diffusion coefficient alpha=1.2*10 7 m² / s.

[0059] Further, in step S8, the embossing die is arranged on the screw machine; The structure parameters of the embossing die are as follows: the corrugation depth is 0.4±0.05mm; the corrugation pitch is 6.5±0.3mm; The flow channel of the embossing die is designed by 6 Bezier curves, and the compression ratio is 1:15. Wherein the corrugated tooth type is involute equation:

[0060] Wherein a=0.4mm, theta belongs to [0, pi]; Further, in the implementation process, the insulation layer material is extruded: A 90mm screw extruder is adopted, and the partition temperature control parameters of the extruder are shown in the following table 3: Table 3 In the implementation process, oxygen-free copper is preferred because of its excellent electrical conductivity, ductility and corrosion resistance, The circular tight pressing stranded conductor: the stranded structure improves flexibility and stability; the tight pressing process reduces the outer diameter of the conductor, saves materials and improves the filling factor.

[0061] The function of the inner conductor shielding layer is to uniformly distribute the electric field on the conductor surface, prevent local discharge due to burrs or gaps on the contact surface between the insulation layer and the conductor, and improve the insulation life and voltage resistance level.

[0062] The function of the outer insulation shielding layer is to uniformly distribute the electric field on the insulation layer surface, and to eliminate the electric field concentration at the air gap or protrusion on the inner and surface of the insulation layer, prevent local discharge. It is also crucial for long-term reliable operation of the cable.

[0063] The role of filling structure and double-layer wrapping tape: 1. Fix the position of the insulated core to form a stable and round cable core structure; 2. Provide mechanical cushioning to reduce the impact of subsequent processes on the inner layer; 3. Provide longitudinal water resistance.

[0064] The role of inner sheath: 1. Bundle and fix the cable core into a round shape to provide a smooth and solid base for the armor layer.

[0065] 2. Protect the cable core from mechanical damage by the armor layer.

[0066] 3. Provide the first waterproof and moisture-proof barrier.

[0067] 4. Isolate the cable core from the armor layer.

[0068] The role of composite armor: 1. Provide strong radial mechanical protection: against pressure, extrusion, impact, gnawing by rodents, etc.

[0069] 2. Provide certain tensile strength enhancement.

[0070] 3. Form part of the electromagnetic shield; The role of outer sheath: 1. Protect all internal structures, especially the armor layer, from environmental factors (moisture, chemicals, soil corrosion, UV light).

[0071] 2. Provide the final electrical insulation barrier.

[0072] 3. Further enhance the mechanical protection of the cable (wear resistance, impact resistance).

[0073] 4. Provide a smooth surface for easy installation.

[0074] Implementation one: According to the needs of the use scene, through design and calculation to select materials, set the material specifications to achieve the use and design effect of the cable, as follows: Conductor unit: oxygen-free copper stranded and compacted conductor, cross-sectional area 16-300 mm²; Double-layer fire-resistant layer: inner phlogopite tape (0.1 mm thick) + outer synthetic mica tape (0.12 mm thick), spiral angle 52°±3°, overlap rate 55%.

[0075] Insulating layer: ceramicized silicone rubber (base rubber is cross-linked polyethylene, adding 40wt% ceramic powder), thickness 1.0-3.0 mm, ceramic conversion rate ≥90% at 550°C; Insulating shield layer: semi-conductive ceramicized silicone rubber (volume resistivity 10²-10³ Ω·cm); Filling structure: ceramicized silicone rubber filling strip, Shore A hardness 65±5; Double-layered wrapping tape: inner layer of alkali-free glass fiber tape (0.15mm thick) + outer layer of fire-resistant mica tape (0.1mm thick), overlap rate 35%; Inner sheath: ceramified silicone rubber, thickness ≥1.5mm; Composite armor layer: inner layer: galvanized steel tape (0.5mm thick, 25mm wide), gap wrapping (gap rate 35%); outer layer: 304 stainless steel tape (0.2mm thick, 28mm wide), reverse full-cover wrapping; Buffer layer: aramid fiber woven mesh (1680D, 16 spindles / inch, coverage rate 90%); Outer sheath: ceramified silicone rubber, surface pressed anti-wear corrugation (0.4mm deep, 6mm apart), oxygen index ≥42.

[0076] The cable manufacturing process of the present application also needs to be detected in real time during and after the completion of the cable manufacturing, and the specific detection includes the following: Gold mica tape lap joint monitoring: X-ray real-time imaging (resolution 10μm) is used, and the defect rate is ≤0.1%; automatic stop compensation wrapping.

[0077] Armor gap detection: Hall sensor array (accuracy 0.01mm) is used to monitor the edge distance of the steel tape; dynamically adjust the steel tape tension.

[0078] Sheath ceramification prediction: near-infrared spectroscopy (wavelength band 1200-2500nm) is used to analyze the Si-O bond conversion rate, and the vulcanization temperature is adjusted.

[0079] After the completion of the cable of the present application, it is tested under various extreme conditions to verify the stability and excellence of its performance.

[0080] I. Thermal-mechanical coupling test: Axial tension 15kN + radial flame jet (1100℃) synchronous loading; Insulation resistance decay rate ≤15% after test.

[0081] II. Chemical corrosion durability: Alternating cycle of immersion in H2SO4 solution with pH=1 + 3.5% NaCl salt spray; Stainless steel tape corrosion weight loss ≤0.8mg / cm² after 504h.

[0082] Through the integrated use of detection methods, the following effects can be achieved: material composite innovation (ceramified silicone rubber / compound mica), structure topology optimization (tension matching armor), process precise control (gradient cooling+online detection) to realize the "fire resistance+pressure resistance+aging resistance" triple protection of the cable under extreme conditions.

[0083] The working principle of the present application is as follows: firstly, a single copper base material is drawn to a set diameter through eight drawing dies; the drawn copper base material is annealed under nitrogen protection, the temperature is 450℃±5℃, and the temperature is kept for 120s; the cooling rate after annealing is 10℃ / s; then, multiple copper base materials are stranded into tight round conductors by a 24-disc stranding machine; then, a double-layer fire-resistant layer is coated by a double-head synchronous wrapping machine, specifically: inner phlogopite tape and outer synthetic mica tape; Secondly, a screw extruder is used to synchronously extrude three layers of insulation layers, specifically: inner conductor shielding layer, middle insulation layer and outer insulation shielding layer, the extrusion pressure is 25±2MPa, and the extrusion speed is 6-8m / min; the coating of the fire-resistant layer is completed, and the production of the insulated core wire is realized; Thirdly, the filling of the ceramicized silicone rubber strip between the insulated core wires is carried out, and the double-layer wrapping of the inner alkali-free glass fiber tape and the outer synthetic mica tape is carried out, so as to achieve the purpose of cabling; Fourthly, the inner sheath is extruded: the ceramicized silicone rubber material is extruded by a vacuum sizing extrusion die, and the outer coating of the cabling structure forms an inner sheath structure after cooling; Fifthly, the composite armor layer is set, the galvanized steel belt gap wrapping and the stainless steel belt full-covering reverse wrapping operations are carried out, and the wrapping operation of the armor layer is realized; Sixthly, the buffer layer coating is carried out: the outer side of the composite armor is coated by the aramid fiber woven net or the ceramic fiber tape by the planetary cabling machine; Finally, the outer sheath extrusion operation is carried out: the ceramicized silicone rubber or low-smoke halogen-free flame-retardant material base material is extruded by a screw machine, and the outer sheath is formed after cooling, thus completing the production of the whole cable.

[0084] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any change or replacement without creative labor should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be limited by the protection scope defined in the claims.

Claims

1. A high-strength, insulated, steel-tape-armored multi-core power cable, characterized in that, From the inside out, it includes: A conductor unit consisting of a copper substrate stranded and compacted conductor and a double-layer fire-resistant layer covering the conductor with an overlap rate of ≥50%, wherein the double-layer fire-resistant layer is composed of an inner layer of phlogopite mica tape and an outer layer of synthetic mica tape; An insulating layer composed of semi-conductive ceramicized silicone rubber and / or cross-linked polyethylene, and extruded outside the refractory layer, the insulating layer comprising an inner conductor shielding layer, a middle insulating layer and an outer insulating shielding layer; The cable is composed of a filler strip made of ceramicized silicone rubber and an auxiliary insulated core wire twisted into a filler structure, and a double-layer wrapping tape composed of an inner layer of alkali-free glass fiber tape with a wrapping overlap rate of ≥30% and an outer layer of synthetic mica tape, which is extruded outside the insulated core wire and the filler structure. An inner sheath made of ceramicized silicone rubber material and extruded over a double-layer wrapping tape; It consists of an inner galvanized steel strip and an outer stainless steel strip, forming a composite armor layer that covers the outside of the inner sheath. A buffer layer consisting of aramid fiber woven mesh or ceramic fiber tape, covering the composite armor layer; An outer sheath composed of ceramicized silicone rubber with an oxygen index ≥40 or low-smoke halogen-free flame arrestor, and extruded outside the buffer layer.

2. The high structural strength insulated steel tape armored multi-core power cable according to claim 1, characterized in that: The inner conductor shielding layer and the outer insulating shielding layer are made of semi-conductive ceramicized silicone rubber, which contains 15% conductive carbon black and has a viscosity index of 1.2 × 10⁻⁶. 4 Pa·s; The ceramicization conversion temperature threshold of the semi-conductive ceramicized silicone rubber is 550℃±20℃, and the high-temperature residual strength is ≥15MPa; The middle insulating layer is made of cross-linked polyethylene, which contains 40% ceramic filler, which is vitrified microspheres and calcined kaolin.

3. The high structural strength insulated steel tape armored multi-core power cable according to claim 1, characterized in that: The composite armor layer has an inner galvanized steel strip with a thickness of 0.5mm ± 0.05mm and an outer stainless steel strip with a thickness of 0.2mm ± 0.02mm. The stainless steel strip is wrapped in reverse to achieve full coverage. The galvanized steel strip has a wrapping gap ratio of ≤40%, a wrapping angle of 28°±2°, and a zinc layer mass of ≥140g / m²; the stainless steel strip has a wrapping angle in the opposite direction of 32°±2°; the misalignment angle between the galvanized steel strip and the stainless steel strip is ≥45°. The galvanized steel strip and the stainless steel strip are coated with a heat-expanding adhesive with a coating amount of 8g / m².

4. A high-strength insulated steel tape armored multi-core power cable according to claim 1, characterized in that: The outer sheath surface is provided with anti-wear corrugated patterns, with a corrugation depth of 0.3 to 0.5 mm and a spacing of 5 to 8 mm.

5. A method for manufacturing the cable according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Conduct conductor unit pretreatment, specifically: perform molding and coating treatment on the copper substrate; S2. A screw extruder is used to simultaneously extrude three layers of insulation; extrusion pressure: 25±2MPa, extrusion speed: 6~8m / min; S3. Perform the insulated core wire cabling operation; S4. Extrusion of inner sheath: ceramicized silicone rubber material is extruded using a vacuum sizing die and then cooled to form the inner sheath; S5. Perform composite armor layer wrapping: perform galvanized steel strip gap wrapping and stainless steel strip full coverage wrapping operations at the front and rear; S6. Apply a buffer layer: Apply an aramid fiber woven mesh or ceramic fiber tape to the outer side of the composite armor. S7. Perform outer sheath extrusion: Extrude ceramicized silicone rubber or low-smoke halogen-free flame-retardant base material through a screw extruder, and then cool to form the outer sheath.

6. The method for producing a high-structural-strength insulated steel tape armored multi-core power cable according to claim 5, characterized in that: The conductor unit preprocessing steps in step S1 are as follows: 1) The copper substrate is drawn to a set diameter through eight drawing dies; 2) The drawn copper substrate was annealed under nitrogen protection at a temperature of 450℃±5℃ and held for 120s; the cooling rate after annealing was 10℃ / s. 3) A 24-coil stranding machine is used to strand the copper substrate into a compacted round conductor; 4) A double-layer fire-resistant layer is wrapped by a dual-head synchronous wrapping machine, specifically: the inner layer of phlogopite tape is wrapped at an angle of 52°±3°, and the outer layer of synthetic mica tape is wrapped at an angle of 48°±3°.

7. The method for producing a high-structural-strength insulated steel tape armored multi-core power cable according to claim 5, characterized in that: During the inner layer wrapping, the phlogopite tape is preheated to 60°C to soften the adhesive; during the outer layer wrapping, the synthetic mica tape is simultaneously sprayed with a silane coupling agent at a concentration of 5 wt%. The overlap angle between the phlogopite mica tape and the synthetic mica tape is ≥90°. They are then hot-pressed and cured by an infrared hot press roller at a temperature of 80℃±5℃ and a pressure of 0.3MPa.

8. A method for producing a high-structural-strength insulated steel tape armored multi-core power cable according to claim 5, characterized in that: In step S2, the screw extruder uses a coat hanger-type split die to extrude the inner conductor shielding layer, the middle insulation layer, and the outer insulation shielding layer. After the insulation layer is extruded, cross-linking is completed in a nitrogen-protected vulcanization channel with a nitrogen purity ≥99.99%, a flow rate of 10L / min, and a vulcanization time of insulation layer thickness × 1.2min / mm, finally forming an insulated core wire.

9. A method for producing a high-structural-strength insulated steel tape armored multi-core power cable according to claim 5, characterized in that: The insulated core wire cabling operation steps in step S3 are as follows: 1) A planetary cable-forming machine is used to twist the insulated core wires in the S direction at 17 times the cable diameter ±5%; 2) Simultaneously fill with ceramicized silicone rubber strips; 3) Double-layer wrapping: the inner layer is wrapped with alkali-free glass fiber tape, and the outer layer is wrapped with synthetic mica tape.

10. A method for producing a high-structural-strength insulated steel tape armored multi-core power cable according to claim 5, characterized in that: In step S6, the aramid fiber woven mesh or ceramic fiber tape has a weaving density of ≥16 spindles / inch and a tensile strength of ≥2800MPa. Meanwhile, the aramid fiber woven mesh adopts three-dimensional weaving technology, and the weaving angle is dynamically adjusted according to a formula: ; Where θ is the angle, R is the cable radius, N is the number of spindles, d is the yarn diameter, and P is the pitch; After weaving, the weaving joints are impregnated with silicone resin, which is then heat-cured to form elastic hinge points. The ceramic fiber tape is made of Al2O3-SiO2 fiber, with two wrapping layers and an overlap rate of 50±5%. When the outer sheath material in step S7 is ceramicized silicone rubber, 5% nano-silicon carbide is added as a thermal conductivity enhancer; after extrusion by the screw extruder, the cable immediately enters the stepped temperature-controlled vulcanizing box; then, three-stage gradient cooling is performed, with a rapid cooling tank, a main cooling tank, and a final cooling tank; the final cooling tank uses vortex tube cooling, which improves the cooling efficiency by 40%, and the surface temperature of the cable after cooling is ≤35℃.

Images