阅读说明：本技术 一种轨道交通用大截面直流牵引电缆及其制造工艺 (Large-section direct-current traction cable for rail transit and manufacturing process thereof ) 是由 陈涛 陈静 徐静 陈兴武 张宇鸥 谢志滨 于 2020-03-27 设计创作，主要内容包括：本发明公开了一种轨道交通用大截面直流牵引电缆及其制造工艺,其中电缆包括由内至外依次设置的导体、包带、乙丙橡皮绝缘、绝缘屏蔽、感知层、薄型阻燃布带和外护套,所述感知层采用信号带电缆,所述外护套采用以EVM为基料的高阻燃橡胶混合料。本发明电缆结构简洁,导体的材料、乙丙橡皮绝缘的材料、薄型阻燃布带的材料和外护套的材料均通过严格筛选,具有优异的安全性能和防水性能,此外,电缆具有高灵敏度的感知结构,能及时监控电缆运行情况,保证线路运行畅通,采用本发明生产工艺可降低了生产制造成本,同时提高生产效率。(The invention discloses a large-section direct-current traction cable for rail transit and a manufacturing process thereof, wherein the cable comprises a conductor, a wrapping tape, an ethylene-propylene rubber insulator, an insulation shield, a sensing layer, a thin flame-retardant cloth tape and an outer sheath which are sequentially arranged from inside to outside, the sensing layer adopts a signal tape cable, and the outer sheath adopts a high-flame-retardant rubber mixture which takes EVM as a base material. The cable has a simple structure, the materials of the conductor, the ethylene propylene rubber insulation, the thin flame-retardant cloth belt and the outer sheath are strictly screened, so that the cable has excellent safety performance and waterproof performance, and in addition, the cable has a high-sensitivity sensing structure, so that the operation condition of the cable can be timely monitored, the smooth operation of a circuit is ensured, the production cost can be reduced by adopting the production process, and the production efficiency is improved.)

1. The utility model provides a big cross-section direct current traction cable for track traffic which characterized in that: comprises a conductor, a wrapping tape, an ethylene-propylene rubber insulating layer, an insulating shielding layer, a sensing layer, a thin flame-retardant cloth tape and an outer sheath which are arranged in sequence from inside to outside; the sensing layer adopts a signal band cable; the outer sheath adopts a high flame-retardant rubber mixture taking EVM as a base material, and the composition and the mixture ratio are as follows by mass: 100 parts of EVM, 100-160 parts of composite flame retardant, 3-5 parts of cross-linking agent, 0.5-2 parts of cross-linking auxiliary agent, 10-15 parts of zinc borate, 3-8 parts of zinc stearate, 3-15 parts of plasticizer, 1-3 parts of anti-aging agent, 5-10 parts of reinforcing agent, 0.5-2 parts of accelerator, 3-5 parts of anti-hydrolysis agent and 8-15 parts of carbon black.

2. The large-section direct-current traction cable for rail transit according to claim 1, wherein: the conductor is formed by twisting a plurality of tinned soft copper wires, the elongation at break of the tinned soft copper wires is more than or equal to 25%, and the direct-current resistivity at 20 ℃ is less than or equal to 0.0175 omega m²/m。

3. The large-section direct-current traction cable for rail transit according to claim 1, wherein: the tensile strength of the ethylene propylene rubber insulating layer is more than or equal to 5.0Mpa, and the elongation at break is more than or equal to 200 percent; the ethylene-propylene rubber insulation meets the air elastic aging test, the aging is accelerated for 42h at 127 ℃, and the retention rate of both tensile strength and elongation at break is more than or equal to 70%; the ethylene-propylene rubber insulation meets the long-term air oven aging experiment, the aging is accelerated at 110 ℃ for 672h, the retention rate of tensile strength is more than or equal to 60%, and the elongation at break is more than or equal to 150%; the ethylene-propylene rubber insulation meets the waterproof performance examination, requires 14 days of long-term water absorption, and has the weight gain of less than or equal to 1mg/cm²The 20 ℃ insulation power factor is less than or equal to 0.035, and the 20 ℃ insulation dielectric constant is less than or equal to 4.

4. The large-section direct-current traction cable for rail transit according to claim 1, wherein: the insulation shield adopts a strippable semi-conductive outer shield layer.

5. The large-section direct-current traction cable for rail transit according to claim 1, wherein: the tensile strength of the thin flame-retardant cloth belt is more than or equal to 65N/cm, the elongation is more than or equal to 15%, and the oxygen index OI is more than 50.

6. The large-section direct current traction for rail transit according to claim 1Lead cable, its characterized in that: the tensile strength of the outer sheath is more than or equal to 8Mpa, and the elongation at break is more than or equal to 150%; the outer sheath material meets the aeroelastic aging test, the aging is accelerated at 127 ℃ for 40h, and the retention rate of both tensile strength and elongation at break is more than or equal to 70%; the outer sheath material meets the requirement of a long-term air oven aging test, aging is accelerated at 120 ℃ for 168h, and the retention rate of tensile strength and elongation at break is more than or equal to 60%; the outer sheath material meets the waterproof performance examination, absorbs water at 70 ℃ for 24 hours, and absorbs water to increase the weight by less than or equal to 5mg/cm²(ii) a The outer sheath material meets the requirements of an oil resistance test, namely an IRM902 test, 100 ℃ and 24 hours, the retention rate of tensile strength and elongation at break is more than or equal to 60%, the oxygen index OI is more than or equal to 40, a temperature test at 143 ℃, the scorching time reaches 5min, a temperature test at 180 ℃, and the normal vulcanization time reaches 6 min; the outer sheath material is made into a test piece, the test piece tests the heat release of the material through a cone calorimeter, and the requirements of the total heat release amount being less than or equal to 40MJ, the peak heat release amount being less than or equal to 150kW, the heat release rate being less than or equal to 52kW, and the total smoke production amount being less than or equal to 1.3m are met²The peak value of the smoke production rate is less than or equal to 0.2m²S, smoke production rate is less than or equal to 0.17m²S; the outer sheath material is made into a sample strip, 500W flame is adopted, and after ignition is carried out for 50s, the dropping time of the outer sheath material is more than or equal to 100 s.

7. A manufacturing process of a large-section direct-current traction cable for rail transit according to any one of claims 1 to 6, comprising:

the method comprises the following steps: manufacturing a conductor, namely taking a tinned soft copper wire as a center, sequentially surrounding the periphery of the tinned soft copper wire in a layered mode, and performing concentric compound twisting, wherein the twisting direction is that each layer of the tinned soft copper wire is twisted left and right alternately;

step two, wrapping a wrapping tape outside the conductor twisted and molded in the step one, wherein the wrapping direction is opposite to the twisting direction of the tinned soft copper wire on the outermost layer, and obtaining a cable core;

step three: co-extruding the ethylene-propylene rubber insulation and the insulation shield on the outer layer of the cable core by using a rubber extruding machine, wherein the insulation shield can be stripped;

step four: wrapping a sensing layer and a thin flame-retardant cloth belt on the outer layer of the insulation shield;

step five: extruding the cable obtained in the fourth step by an extruding rubber machine to wrap an outer sheath for sample production, then carrying out performance verification, and carrying out the next step after the detection is passed;

step six: and E, extruding the outer layer of the cable qualified in the step five by using an extruding rubber machine to wrap the outer sheath to manufacture a finished cable.

8. The manufacturing process of the large-section direct-current traction cable for rail transit according to claim 7, wherein the manufacturing process comprises the following steps: in the fourth step, the sensing layer and the thin flame-retardant cloth belt are wrapped simultaneously, and the thin flame-retardant cloth belt is wrapped by adopting a low-smoke halogen-free belt.

9. The manufacturing process of the large-section direct-current traction cable for rail transit according to claim 7, wherein the manufacturing process comprises the following steps: and fifthly, verifying the performance including but not limited to a bundling combustion A-type test, wherein cable combustion is required for 40min, the combustion height is not more than 2.5m, and the smoke density is not less than 70%.

Technical Field

The invention belongs to the technical field of cables, and particularly relates to a large-section direct-current traction cable for rail transit and a manufacturing process thereof.

Background

The rail transit designed abroad enters the electrification era in 1881, the design at home and abroad is greatly different in the aspect of traction cables, the positive pole and the negative pole are distinguished, the positive pole is mainly used for traction power, and the negative pole is mainly used for line backflow. The direct current traction cable for the rail transit in China is mostly produced and designed by adopting the GB/T28429-2012 standard, each layer structure has corresponding functions, such as water resistance, fire insulation, flame retardance, rat and ant prevention and the like, the structure is complex, the production and manufacturing cost is higher, and the direct current traction cable is greatly different from the design of a foreign direct current cable.

Disclosure of Invention

The invention aims to provide a large-section direct-current traction cable for rail transit and a manufacturing process thereof, which simplify the cable structure and ensure that the cable has excellent safety performance and waterproof performance.

The technical scheme for realizing the purpose of the invention is as follows:

the utility model provides a large cross-section direct current traction cable for track traffic, includes conductor, band, ethylene-propylene rubber insulation, insulation shield, perception layer, slim fire-retardant strap and the oversheath that sets gradually from inside to outside, the perception layer adopts the signal band cable, the oversheath adopts the high fire-retardant rubber mixture who uses EVM as the base stock, and its constitution and ratio are counted with the part by mass: 100 parts of EVM, 100-160 parts of composite flame retardant, 3-5 parts of cross-linking agent, 0.5-2 parts of cross-linking auxiliary agent, 10-15 parts of zinc borate, 3-8 parts of zinc stearate, 3-15 parts of plasticizer, 1-3 parts of anti-aging agent, 5-10 parts of reinforcing agent, 0.5-2 parts of accelerator, 3-5 parts of anti-hydrolysis agent and 8-15 parts of carbon black.

Furthermore, the conductor is formed by twisting a plurality of tinned soft copper wires, and the elongation at break of the tinned soft copper wires is required to be more than or equal to 25 percent, and the direct-current resistivity at 20 ℃ is required to be less than or equal to 0.0175 omega m²The cross section of the conductor reaches 800m²。

Furthermore, the tensile strength of the ethylene propylene rubber insulation is more than or equal to 5.0Mpa, the elongation at break is more than or equal to 200%, and strict aging test and waterproof performance examination are met. Air bomb aging test, 127 deg.CThe aging is accelerated for 42h, and the retention rate of the tensile strength and the elongation at break are both more than or equal to 70 percent; for a long-term air oven aging experiment, accelerated aging is carried out for 672h at 110 ℃, the retention rate of tensile strength is more than or equal to 60 percent, and the elongation at break is more than or equal to 150 percent; the waterproof performance is checked, the long-term water absorption is required in 14 days, and the weight gain of the insulating water absorption is less than or equal to 1mg/cm²The 20 ℃ insulation power factor is less than or equal to 0.035, and the 20 ℃ insulation dielectric constant is less than or equal to 4.

Further, the insulation shield adopts a strippable semi-conductive outer shield layer.

Furthermore, the tensile strength of the thin flame-retardant cloth belt is more than or equal to 65N/cm, the elongation is more than or equal to 15%, and the oxygen index OI is more than 50.

Furthermore, the tensile strength of the outer sheath is more than or equal to 8Mpa, the elongation at break is more than or equal to 150%, and the strict aging test, waterproof performance examination, heat release examination, smoke production characteristic examination and carbon formation examination are met. In an air elastic aging test, accelerated aging is carried out for 40h at 127 ℃, and the retention rate of both tensile strength and elongation at break is more than or equal to 70 percent; the aging test of a long-term air oven shows that the aging is accelerated at 120 ℃ for 168 hours, the retention rate of tensile strength and elongation at break is more than or equal to 60 percent, the waterproof performance is checked, the water is absorbed at 70 ℃ for 24 hours, and the water absorption weight gain is less than or equal to 5mg/cm²(ii) a Oil resistance test, IRM902, 100 ℃, 24 hours, tensile strength and elongation at break retention rate of more than or equal to 60 percent, oxygen index OI of more than or equal to 40, 143 ℃ temperature test, scorching time of 5min, 180 ℃ temperature test, and normal vulcanization time of 6 min; making the outer sheath material into a test piece, and testing the heat release of the material by a cone calorimeter, wherein the total heat release amount is less than or equal to 40MJ, the peak heat release value is less than or equal to 150kW, the heat release rate is less than or equal to 52kW, and the total smoke production amount is less than or equal to 1.3m²The peak value of the smoke production rate is less than or equal to 0.2m²S, smoke production rate is less than or equal to 0.17m²S; the outer sheath material is made into a sample strip, 500W flame is adopted, and after ignition is carried out for 50s, the dropping time of the outer sheath material is more than or equal to 100 s.

A manufacturing process of a large-section direct-current traction cable for rail transit comprises the following steps:

the method comprises the following steps: manufacturing a conductor, namely taking a tinned soft copper wire as a center, sequentially surrounding the periphery of the tinned soft copper wire in a layered mode, and performing concentric compound twisting, wherein the twisting direction is that each layer of the tinned soft copper wire is twisted left and right alternately;

step two, wrapping a wrapping tape outside the conductor twisted and molded in the step one, wherein the wrapping direction is opposite to the twisting direction of the tinned soft copper wire on the outermost layer, and the covering rate is 15-20%, so that a cable core is obtained;

step three: co-extruding ethylene-propylene rubber insulation and insulation shielding on the outer layer of the cable core by using a rubber extruding machine, wherein the insulation shielding can be stripped, and the stripping force is 20-35N;

step four: wrapping a sensing layer and a thin flame-retardant cloth belt on the outer layer of the insulation shield;

step five: extruding the cable obtained in the fourth step by an extruding rubber machine to wrap an outer sheath for sample production, then carrying out performance verification, and carrying out the next step after the detection is passed;

step six: and E, extruding the outer layer of the cable qualified in the step five by using an extruding rubber machine to wrap the outer sheath to manufacture a finished cable.

Further, in the fourth step, the sensing layer and the thin flame-retardant cloth belt are wrapped simultaneously, the thin flame-retardant cloth belt is wrapped by a low-smoke halogen-free belt in two layers, and the covering rate is 40-50%.

Further, in the fifth step, the performance verification comprises but is not limited to a bundling combustion A type test, the cable of the sample is required to be combusted for 40min, the combustion height is not more than 2.5m, and the smoke density is more than or equal to 70%.

By adopting the technical scheme, the invention has the following beneficial effects:

(1) the cable is simple in structure, the outer sheath is made of high-flame-retardant rubber mixture with EVM as base material, the high-flame-retardant cable is high in elasticity and excellent in mechanical property, the composite halogen-free flame retardant is adopted, the oxygen index can reach 40-50, the high-flame-retardant cable is high in flame-retardant property, halogen-free and environment-friendly, the high-temperature-resistant cable is good in temperature resistance, the maximum service temperature can reach 125 ℃ for a long time, and the high-safety cable is excellent in safety performance and waterproof performance.

(2) The cable conductor adopts the tinned soft copper wire, is corrosion-resistant and has high current-carrying capacity, the cross section of the cable reaches more than 800 square, and the cable adopts direct current transmission, and the current-carrying capacity exceeds 1520A and is more than 2 times of that of the conventional direct current cable.

(3) The cable insulation and sheath materials are subjected to strict aging test and waterproof performance examination, the cable can meet 50-year operation, meanwhile, the waterproof and flame-retardant requirements can be met without special structures such as a waterproof layer, a fire barrier layer, a waterproof layer and the like, the production cost is reduced by 20%, and the production efficiency is improved by 30%.

(4) The sheath material adopted by the invention is specially screened, the sample qualification rate is ensured, the final finished cable is ensured to meet the A class of bundled combustion from the aspects of heat release, smoke generation property and carbon formation property, the combustion performance is B1 grade, the combustion height is not more than 1m, and the smoke density of the cable is more than 70%.

(5) According to the cable production process, through special sample performance verification, the production process of the sheath can be confirmed, the research and development time of products is shortened, meanwhile, the waste of sample trial production in the research and development process can be reduced, a conventional production flow is adopted, a cable with the thickness of 100-150 m is required in the vulcanization process, the sample can be prepared according to the test requirement in the product performance verification process, and the sample cost is saved by more than 60%.

Drawings

In order that the present disclosure may be more readily and clearly understood, reference is now made to the following detailed description of the present disclosure taken in conjunction with the accompanying drawings, in which:

fig. 1 is a schematic view of the cable structure of the present invention.

The reference numbers in the drawings are as follows: the cable comprises a conductor 1, a wrapping tape 2, an ethylene-propylene rubber insulator 3, an insulation shield 4, a sensing layer 5, a thin flame-retardant cloth tape 6 and an outer sheath 7.

Detailed Description

The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.

The invention provides a large-section direct-current traction cable for rail transit and a manufacturing process thereof, which are used for solving the problems that a direct-current cable for rail transit in the prior art is complex in structure, high in production cost and incapable of monitoring the running condition of the cable.

(example 1)

Referring to fig. 1, the large-section direct-current traction cable for rail transit in the embodiment includes a conductor 1, a tape 2, an ethylene-propylene rubber insulation 3, an insulation shield 4, a sensing layer 5, a thin flame-retardant cloth tape 6 and an outer sheath 7, which are sequentially arranged from inside to outside, wherein the tape 2 is a semiconductive nylon tape, and the insulation shield 4 is a strippable semiconductive outer shield layer.

The conductor 1 is formed by stranding 91 tinned soft copper wires with the wire diameter of 3.4mm, is corrosion-resistant and high in current carrying capacity, the breaking elongation of each tinned soft copper wire is more than or equal to 25 percent, and the direct-current resistivity at 20 ℃ is less than or equal to 0.01750 omega mm²And/m. The twisting is carried out by adopting a structure of 1+6+12+18+24+30, and the twisting pitches of the control conductor 1 are as follows from inside to outside in sequence: 253-303 mm, 421-505 mm, 472-590 mm, 455-607 mm, 482-556 mm. The outer diameter of the conductor 1 is controlled to be 37.1-37.4 mm, the breaking elongation of the tinned soft copper wire is 28%, and the direct-current resistivity at 20 ℃ is 0.01725 omega mm²M, the outer diameter of the conductor 1 is 37.2mm, and the section reaches 800m²The direct current transmission is adopted, the current-carrying capacity exceeds 1520A, and is more than 2 times of that of a conventional direct current cable; the domestic conventional frame stranding machine adopts 91 wires for stranding at the maximum, so that the maximum conductor section which can be achieved by production can be met without increasing equipment; the combination pitch control is calculated according to the pitch-diameter ratio, the pitch-diameter ratio is gradually reduced from the inner layer to the outer layer, and the twisting is not easy to break and clamp a die, so that the tight twisting and the loosening are ensured.

The average thickness of the ethylene-propylene rubber insulator 3 is more than or equal to 4.5mm, the thinnest point thickness is more than or equal to 4.0mm, the insulation performance is required, the tensile strength is more than or equal to 5.0Mpa, the elongation at break is more than or equal to 200%, and the strict aging test and waterproof performance check are met. Ethylene-propylene rubber padThe average thickness of the edge 3 is 4.8mm, the thickness of the thinnest point is 4.1mm, the tensile strength before the aging test is 8Mpa, and the elongation at break is 300%. In the air spring aging test, accelerated aging is carried out for 42 hours at 127 ℃, the retention rate of tensile strength and elongation at break are required to be more than or equal to 70%, and after the air spring aging test, the retention rate of tensile strength and elongation at break is 85-95%; in a long-term air oven aging test, accelerated aging at 110 ℃ for 672h requires that the retention rate of tensile strength is more than or equal to 60 percent and the elongation at break is more than or equal to 150 percent, and the retention rate of tensile strength is actually measured in the long-term oven aging test of the embodiment to be 90-98 percent and the elongation at break is 250-300 percent; the waterproof performance is checked, the long-term water absorption is required in 14 days, and the weight gain of the insulating water absorption is less than or equal to 1mg/cm²The insulation power factor at 20 ℃ is less than or equal to 0.035, the insulation dielectric constant at 20 ℃ is less than or equal to 4, the actual measurement of the water absorption weight gain of the embodiment is 0.05mg/cm²The 20 ℃ insulation power factor is 0.021, and the 20 ℃ insulation dielectric constant is 3.0-3.1.

Perception layer 5 adopts the signal band cable, and thickness is no longer than 0.2mm, width 15mm, and 5 thickness on this embodiment perception layer are 0.18mm to clearance spiral winding's mode cladding is outside the insulation shield 4 of cable. And a micro-current is introduced into the sensing layer 5, and when the temperature of the cable is increased and damaged, the micro-current changes, so that a signal is fed back to the terminal, and the cable is maintained in time.

The average thickness of the thin flame-retardant cloth belt 6 is 0.08mm, the tensile strength is more than or equal to 65N/cm, the elongation is more than or equal to 15%, the oxygen index OI is more than 50, the tensile strength of the embodiment is 73N/cm, the elongation is 22%, and the oxygen index is 65.

The outer sheath 7 adopts a high flame-retardant rubber mixture taking EVM as a base material, and comprises the following components in parts by mass: 100 parts of EVM700HV 100, 120 parts of composite flame retardant, 5 parts of crosslinking agent DCP, 0.5 part of crosslinking assistant TAC, 13 parts of zinc borate, 4 parts of zinc stearate, 4 parts of plasticizer TOTM, 4 parts of anti-aging agent RD/40101.5 parts of reinforcing agent silicon oxide, 1 part of accelerator TBTD-70/ETU, 3 parts of hydrolysis-resistant agent polycarbodiimide and 10 parts of carbon black. The average insulation thickness is more than or equal to 4.5mm, the thinnest point is not less than 4.0mm, the tensile strength is more than or equal to 8Mpa, the elongation at break is more than or equal to 150%, the actual measured tensile strength of the material of the outer sheath 7 in the embodiment is 12Mpa, and the elongation at break is 205%. Require to meet strict aging test and preventionWater performance assessment, heat release assessment, smoke production characteristic assessment and carbon formation assessment. The insulation of this example has an average thickness of 4.7mm and a thinnest point thickness of 4.1 mm. In the air spring aging test, aging is accelerated at 127 ℃ for 40h, the retention rate of tensile strength and elongation at break is more than or equal to 70%, and the actual measurement of the retention rate of tensile strength and elongation at break of the air spring aging test is 90% -95%; in a long-term air oven aging test, aging is accelerated at 120 ℃ for 168 hours, the retention rate of tensile strength and elongation at break is more than or equal to 60%, and the actual measurement of the retention rate of tensile strength and elongation at break of the long-term air oven aging test is 90% -95%; the waterproof performance is checked, the water is absorbed for 24 hours at 70 ℃, and the weight gain is less than or equal to 5mg/cm²In this example, the measured water absorption weight gain is 0.5mg/cm²The method comprises the following steps of (1) taking a proper amount of rubber sheet, putting the rubber sheet into a mold with the length of ×, the width of × and the thickness of 100mm × 100mm × 3mm, vulcanizing the rubber sheet on a flat vulcanizing machine, the temperature of 180 ℃, the pressure of 5MPa to 6MPa, stopping heating and pressure maintaining for 15min, testing the heat release of the material of the prepared test piece through a cone calorimeter, wherein the total heat release amount is less than or equal to 40MJ, the peak heat release value is less than or equal to 150kW, the heat release rate is less than or equal to 52kW, and the total smoke generation amount is less than or equal to 1.3m²The peak value of the smoke production rate is less than or equal to 0.2m²S, smoke production rate is less than or equal to 0.17m²S; (2) the material is made into a sample strip with the length of 200mm and the width of 10mm, 500W flame is adopted, and after ignition is carried out for 50s, the time for dripping the sheath material is more than or equal to 100 s.

A manufacturing process of a large-section direct-current traction cable for rail transit comprises the following steps:

the method comprises the following steps: conductor 1 preparation, 91 tinned soft copper wires divide six layers to encircle in proper order all around, adopt 1+6+12+18+24+30 structure to carry out concentric compound hank, the first layer is 1 tinned soft copper wire promptly, the second floor is 6 tinned soft copper wires and encircles the first layer of parcel, analogize to this, the 6 th floor is that 30 tinned soft copper wires encircle parcel 5 th floor, every two liang of tangent settings of adjacent tinned soft copper wire of layer, the direction of transposition is left direction + right direction + left direction.

And step two, winding the conductor 1 twisted and molded in the step one by using a semi-conductive nylon tape, wherein the winding direction is the right direction, and the covering rate is 18%, so that a cable core is obtained.

Step three: and co-extruding the ethylene-propylene rubber insulation 3 and the insulation shield 4 on the outer layer of the cable core by using an extrusion rubber machine, wherein the insulation shield 4 can be stripped, and a strippable semi-conductive outer shield layer is adopted, the stripping force is 30N, and the thickness is 0.6 mm. The ethylene propylene rubber insulation 3 is produced by adopting a 150-extrusion rubber machine, the temperature of the machine body is 90-100 ℃, and the temperature of the machine body is set to be 95 ℃ in the embodiment; the strippable semi-conductive outer shielding layer is produced by a 90-degree rubber extruding machine, the temperature of the machine body is 90-100 ℃, and the temperature of the machine body is set to be 95 ℃ in the embodiment; the temperature of the machine head during co-extrusion is set to be 80-100 ℃, and the temperature of the machine head in the embodiment is set to be 90 ℃; the production speed is 7-8 m/min, the air pressure is 7-9 bar, the temperature of the vulcanizing tube is 170-190 ℃, the production speed is 7m/min, the air pressure is 8bar, and the temperature of the vulcanizing tube is 180 ℃.

Step four: a sensing layer 5 and a thin flame-retardant cloth belt 6 are wrapped on the outer layer of the insulation shield 4; perception layer 5 and slim fire-retardant strap 6 are simultaneously around the package, take 45% of the rate of covering, improve production efficiency, and perception layer 5 adopts clearance spiral winding's mode, and the clearance is 3 ~ 5mm, and this embodiment clearance sets for 4mm, and slim fire-retardant strap 6 adopts low smoke and zero halogen area to wind the package two-layerly.

Step five: extruding the cable obtained in the fourth step by an extruding rubber machine to wrap an outer sheath 7 for sample preparation, then performing performance verification, and performing the next step after the detection is passed; the performance verification comprises but is not limited to a bundling combustion class A test, and the specific method comprises the steps of extruding a sheath material with the thickness of about 5.5mm on the surface of a wire core by using a 150 extruding machine, controlling the outer diameter of the cable to be 60.5-61.0 mm, putting the cable into a mould press, enabling the mould of the mould press to be circular, enabling the inner diameter to be 59.5-60.0 mm, enabling the length of the mould to be about 600mm, coating a high-viscosity polysiloxane release agent in the mould, controlling the pressure of the mould press to be 9-12 MPa, controlling the temperature to be 175-185 ℃, maintaining the pressure for 30 min. Preparing samples with the length of 0.6-3.5 m as required, and performing a bundled combustion A type test on 4 samples, wherein the cable of the sample is required to be combusted for 40min, the combustion height is not more than 2.5m, and the smoke density is not less than 70%. In the bundled combustion type A test of the embodiment, a plastic extruding machine extrudes a sheath material with the thickness of 5.5mm on the surface of a wire core, the outer diameter of a cable is 60.8mm, the pressure of a molding press is 10Mpa, the temperature is 180 ℃, samples with the length of 3.5m are prepared, 4 samples are taken to carry out the bundled combustion type A test, the sample cable is combusted for 40min, the combustion height is 0.5m, and the smoke density is 80%. According to the embodiment, through special sample performance verification, the production process of the outer sheath 7 can be confirmed, the research and development time of products is shortened, meanwhile, the waste of sample trial production in the research and development process can be reduced, a conventional production flow is adopted, a cable with the length of 100-150 m is required in the vulcanization process, the sample can be prepared according to the test requirement in the product performance verification process, and the sample cost is saved by more than 60%.

Step six: and (5) extruding the outer layer of the cable qualified in the fifth step by using an extruding rubber machine to wrap the outer sheath 7 to manufacture a finished cable. The production is carried out by adopting a 150-degree rubber extruding machine, the temperature of a machine body is 100-110 ℃, the temperature of a machine head is set to be 90-110 ℃; the production speed is 5-6 m/min, the air pressure is 9-12 bar, and the temperature of the vulcanizing tube is 180-200 ℃. In the embodiment, the temperature of the machine body is 105 ℃, and the temperature of the machine head is set to be 100 ℃; the production speed is 6m/min, the air pressure is 10bar, and the temperature of the vulcanizing tube is 190 ℃.

The cable is simple in structure, the sheath is made of a high-flame-retardant rubber mixture with EVM as a base material, the high-flame-retardant rubber mixture is high in elasticity and excellent in mechanical property, a composite halogen-free flame retardant is adopted, the oxygen index can reach 40-50, the high-flame-retardant rubber mixture is high in flame-retardant property, halogen-free and environment-friendly, the high-temperature-resistant performance is good, the long-term maximum use temperature can reach 125 ℃, the high-safety performance and the high-waterproof performance are good, in addition, the cable is provided with a high-sensitivity sensing structure, the operation condition of.

In the embodiment, the cable insulation and sheath materials are subjected to strict aging test and waterproof performance examination, the cable can meet 50-year operation, waterproof and flame-retardant requirements can be met without special structures such as a waterproof layer, a fire barrier layer, a waterproof layer and the like, the production cost is reduced by 20%, and the production efficiency is improved by 30%

(example 2)