A high fire resistant medium voltage cable and a process for processing a high fire resistant coating for cables

Abstract

The application discloses a high-fire-resistance medium-voltage cable and a processing technology of a high-fire-resistance coating of the cable, and belongs to the technical field of high-fire-resistance cable production. The high-fire-resistance medium-voltage cable comprises a cable core, and a fire-resistant coating is formed on the surface of the cable core and is solidified; a protective rubber layer is arranged outside the fire-resistant coating in a spaced mode, and a tear-resistant pull rope is arranged between the protective rubber layers; after the tear-resistant pull rope is impregnated with glue, the tear-resistant pull rope is deformed by pressure of a pressure roller and is attached to the fire-resistant coating; the tear-resistant pull rope is bonded to the fire-resistant coating; an outer sheath is arranged outside the protective rubber layer; the outer sheath is filled between the tear-resistant pull rope and the protective rubber layer; the processing technology of the high-fire-resistance medium-voltage cable and the high-fire-resistance coating of the cable can process and roll the cable coated with the fire-resistant coating separately, and cannot cause abrasion of the fire-resistant coating, and in addition, can make the fire-resistant coating more uniform in thickness distribution around the cable core.

Description

TECHNICAL FIELD

[0001] The application relates to a high-fire-resistance medium-voltage cable and a processing technology of a high-fire-resistance cable coating, and belongs to the technical field of high-fire-resistance cable production. BACKGROUND

[0002] A medium-voltage cable must adopt cross-linked polyethylene insulation, and the cross-linked polyethylene insulation has poor high-temperature resistance. In order to make the medium-voltage cable have fire resistance, a protective shell is added outside the insulated core to prevent the flame and heat from entering the inside of the cable, so that the medium-voltage cable has the fire resistance. At present, the fire-resistant structure of the medium-voltage fire-resistant cable on the market is composed of a temperature-insulating layer and a fire-blocking layer from inside to outside, and the thicknesses of the temperature-insulating layer and the fire-blocking layer are relatively large, which increases the outer diameter and weight of the cable, increases the difficulty of installation and laying of the cable, and more importantly, the fire-blocking layer hinders the heat dissipation of the cable and affects the current-carrying capacity of the cable. Therefore, a high-fire-resistance medium-voltage cable and a processing technology of a high-fire-resistance cable coating are disclosed in Chinese Patent Publication No. CN116072356A, wherein the high-fire-resistance coating is produced in series with the outer sheath of the cable. The processing technology of the high-fire-resistance cable coating and the high-fire-resistance coating of the high-fire-resistance medium-voltage cable produced by the processing technology are produced in series with the outer sheath, and can meet the fire resistance requirements of the medium-voltage cable. When the existing medium-voltage cable is processed, if a production line is directly used to complete the cable production and is offline, the cable production efficiency is easily affected. If the fire-resistant coating and the outer layer are produced separately, the cable core is wound after production, and the fire-resistant coating is easily abraded, which leads to failure of the fire protection. In addition, when the existing cable core is processed, the fire-resistant coating of the cable core is easily eccentric, and the thickness on the surface of the cable core is inconsistent. SUMMARY

[0003] To solve the above problems, the application provides a processing technology of a high-fire-resistance medium-voltage cable and a high-fire-resistance cable coating, which can process and wind the cable with the solidified fire-resistant coating separately, will not cause abrasion of the fire-resistant coating, and can make the fire-resistant coating on the surface of the cable core more uniform in thickness.

[0004] The high-fire-resistance medium-voltage cable comprises a cable core, the surface of the cable core is provided with a fire-resistant coating processed by the processing technology of the high-fire-resistance cable coating, and an anti-tear pull rope is arranged between protective rubber layers. After the anti-tear pull rope is dipped in glue, the anti-tear pull rope is filled between the protective rubber layers by a press wheel. The anti-tear pull rope is deformed by the pressure of the press wheel, so that the anti-tear pull rope is fully attached to the surface of the cable core. The anti-tear pull rope is bonded to the fire-resistant coating. The protective rubber layers are externally covered with an outer layer. The outer layer is filled between the anti-tear pull rope outside and the protective rubber layers. The anti-tear pull rope is simple and convenient to install, and can quickly install the anti-tear pull rope and the cable core.

[0005] Further, the outer cladding layer comprises an inner cladding layer and an outer cladding layer; an electromagnetic shielding armored layer is arranged between the inner cladding layer and the outer cladding layer, and electromagnetic shielding is realized through the electromagnetic shielding armored layer, and the structure strength of the cable can be enhanced by cooperating with the anti-tearing pull rope.

[0006] The processing technology of the cable high fire-resistant coating of the application is used for processing the fire-resistant coating of the high fire-resistant medium-voltage cable, and comprises the following production process:

[0007] In the first step, cleaning and drying, the cable core is cleaned through the ultrasonic cleaning equipment, then is flushed through the spray head, and after the flushing is completed, is air-dried through the air knife, and then is dried in the front-end drying pipeline;

[0008] In the second step, inner heating of the cable core, the dried cable core is heated through the eddy current heater;

[0009] In the third step, coating of the fire-resistant coating, after the heating and heat conduction of the cable core, the cable core enters the coating equipment, and the temperature of the cable core entering the coating equipment is kept at 50-60 DEG C; then, the surface of the cable core is heated and coated with the fire-resistant coating through the coating equipment, so that the fire-resistant coating is quickly coated and adhered to the surface of the cable core;

[0010] In the fourth step, core setting and thickness setting, since the fire-resistant coating is heated from inside to outside, the side of the fire-resistant coating close to the cable core is first solidified, and the side far away from the cable core is still in a flowing state, therefore, after passing through the core setting sleeve, the excess fire-resistant coating is scraped off by the core setting sleeve; in the scraping-off process, the outer surface of the fire-resistant coating is simultaneously heated and solidified by the core setting sleeve, so that the overall solidification of the fire-resistant coating is realized; the core setting sleeve is used for positioning the axial line of the cable core and limiting the thickness of the fire-resistant coating of the cable core.

[0011] In the fifth step, solidification of the fire-resistant coating, the cable core after the thickness setting of the coating enters the rear-end drying pipeline; the temperature of the rear-end drying pipeline is 60-65 DEG C; the cable core is heated through the eddy current heater, and the heat is conducted through the cable core and the outer drying of the rear-end drying pipeline, so that the cable core and the fire-resistant coating are fully baked and solidified, and a uniform and stable fire-resistant coating is formed on the surface of the cable core; the preliminarily solidified fire-resistant coating is secondarily solidified through the rear-end drying pipeline.

[0012] In the sixth step, after the cable core is processed with the fire-resistant coating, the cable core enters the rubber coating equipment, and a strip-shaped protective rubber layer is coated on the outside of the fire-resistant coating through the rubber coating equipment.

[0013] Further, the number of coating layers of the fire-resistant coating is 2-5; each additional coating layer is repeated once the steps from the second step to the fourth step; the multi-coating mode can reduce the thickness of single coating, so that the thickness of the fire-resistant coating can be better limited.

[0014] Further, the refractory coating is coated by using cross-shaped roller coating, and adjacent cross-shaped roller coatings are arranged staggeredly; when using cross-shaped roller coating, adjacent groups of cross-shaped roller coatings are positioned mutually, which can prevent the cable core axis from deviating from the coating center line; and the refractory coating is prevented from being coated deviated, so that the refractory coating has inconsistent thickness distribution on the cable core periphery.

[0015] Further, the vortex heater is installed at the output end of the rear-end drying pipeline; the cable core is heated and conducted by the vortex heater, and the cable core is heated and kept at 50-60℃ by heat conduction before entering the coating equipment; the cable core is heated and conducted by the vortex heater, and the heat is conducted to the front-end coating equipment by heat conduction; after the cable core is coated by the coating equipment, the refractory coating is separated from the coating equipment, and the refractory coating continuously approaches the vortex heater during the separation process; the closer to the vortex heater, the higher the temperature of the cable core; and the inner surface of the refractory coating can be solidified quickly.

[0016] Further, a temperature transmitter is arranged on the front side of the coating equipment opposite to the cable core, and the temperature transmitter is linked with the vortex heater through the controller; the temperature of the cable core is monitored by the temperature transmitter, and the heating temperature of the vortex heater is controlled according to the temperature, so that the cable core entering the coating equipment is kept at the set temperature.

[0017] Further, the cable core positioning guide sleeve is installed at the input end of the coating equipment and the output end of the rear-end drying pipeline; the cable core positioning guide sleeve comprises a frame seat, a wheel seat is slidably arranged on the inner side of the frame seat through a slide post, a guide wheel is rotatably arranged on the wheel seat, a positioning bolt passes through the frame seat, the positioning bolt is movably embedded in the wheel seat and fixed with the wheel seat, and a jam nut is rotatably connected to the positioning bolt on both sides of the frame seat; the cable core positioning sleeve shell is adjusted online, the gap between adjacent guide wheels is adjusted by rotating the positioning bolt, so that the cable core can be positioned and guided to roll.

[0018] Further, after the cable core completes the refractory coating processing, the cable core enters the rubber coating equipment, and a protective rubber layer is coated on the outside of the refractory coating by the rubber coating equipment; the thickness of the protective rubber layer is 0.2-3mm, and the protective rubber layer is cross-shaped roller coated; after the protective rubber layer is roller coated and cooled and shaped by the cooling equipment, the cable core is sent to the rolling equipment to be rolled; the protective rubber layer can form a flexible protection support system on the surface of the refractory coating, which can prevent the refractory coating from being scratched by friction; and the thickness of the protective rubber layer can be determined according to the diameter of the tear-resistant pulling rope.

[0019] Further, an electric heating wire is wound on the outer surface of the core positioning sleeve; and a heat insulation sleeve is coated outside the electric heating wire; the core positioning sleeve is heated by the electric heating wire, the cable core entering the core positioning sleeve is quickly heated outside by the core positioning sleeve, and the outer surface of the refractory coating with a certain thickness is quickly baked and fixed, so that the microfluid surface can be quickly solidified.

[0020] Compared with the prior art, the high fire-resistant medium voltage cable and the processing technology of the high fire-resistant coating of the cable of the present application can process and roll the cable coated with the cured fire-resistant coating separately, and the adjacent cable cores after rolling are isolated from each other by the protection of the protective rubber layer; the fire-resistant coatings do not contact each other, which can protect the fire-resistant coatings and prevent the abrasion of the fire-resistant coatings; in addition, the adjacent protective rubber layers form grooves; the arrangement and installation of the anti-tear pull rope are facilitated; the anti-tear pull rope is prevented from being separated from the installation position; the cable installation is more convenient; in addition, the positioning of the adjacent core positioning guide sleeve and the positioning of the thickness of the core positioning sleeve and the positioning of the cross-shaped roller coating can ensure that the thickness of the fire-resistant coating distributed on the surface of the cable core is more uniform. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The figure is a schematic diagram of the structure of the cable core coated with the protective rubber layer by the gluing equipment of the present application.

[0022] Figure 2 The figure is a schematic diagram of the processing flow of the high fire-resistant coating of the cable of the present application.

[0023] Figure 3 The figure is a schematic diagram of the coating line structure of the high fire-resistant coating of the cable of the present application.

[0024] Figure 4 The figure is a schematic diagram of the structure of the cross-shaped roller coating unit of the present application. Figure 3 The figure is a schematic diagram of the structure of the cross-shaped roller coating unit of the present application.

[0025] Figure 5 The figure is a schematic diagram of the production line structure for completing the second to fourth steps of the production process of the present application.

[0026] Figure 6 The figure is a schematic diagram of the structure of the core positioning guide sleeve of the present application.

[0027] Figure 7 The figure is a schematic diagram of the structure of the cross-shaped roller coating unit of the present application.

[0028] Figure 8 The figure is a schematic diagram of the structure of the cross-shaped roller coating unit of the present application.

[0029] The figure is a schematic diagram of the structure of the cross-shaped roller coating unit of the present application. Detailed Implementation

[0030] Example:

[0031] like Figure 1 The high fire-resistant medium-voltage cable shown includes a cable core 7, the surface of which is provided with a fire-resistant coating, and rubber layers 20 are spaced apart outside the fire-resistant coating; it also includes tear-resistant pull ropes 21 disposed between the protective rubber layers 20; after the tear-resistant pull ropes 21 are impregnated with rubber, they are pressed and filled between the protective rubber layers 20 by a pressure roller, and the tear-resistant pull ropes 21 are deformed by the pressure roller, so that the tear-resistant pull ropes 21 are fully attached to the surface of the cable core 7; the tear-resistant pull ropes 21 are bonded to the fire-resistant coating; the protective rubber layers 20 are covered with an outer sheath 22; the outer sheath 22 is filled between the outside of the tear-resistant pull ropes 21 and the protective rubber layers 20, and the tear-resistant pull ropes 21 are simple and convenient to install, and can be quickly installed with the cable core 7.

[0032] The outer sheath 22 includes an inner sheath and an outer sheath; an electromagnetic shielding armor layer is provided between the inner sheath and the outer sheath. Electromagnetic shielding is achieved through the electromagnetic shielding armor layer, and together with the tear-resistant pull rope 21, the structural strength of the cable can be strengthened.

[0033] like Figures 2 to 8 The processing technology for the high fire-resistant coating of the cable shown includes the following production processes:

[0034] The first step is cleaning and drying. The cable core 7 is cleaned by ultrasonic cleaning equipment 1, then rinsed by spray head 2, and then dried by air knife 3. Finally, it enters the front drying pipe 4 for drying.

[0035] The second step is to heat the cable core 7 internally. After the cable core 7 has been dried, it enters the eddy current heater 5 and is heated by the eddy current heater 5.

[0036] The third step is the application of a fire-resistant coating. After the cable core 7 is heated and heat is conducted, it enters the coating equipment 6. The temperature of the cable core 7 entering the coating equipment 6 is maintained at 50~60℃. Then, the fire-resistant coating is applied to the surface of the cable core 7 by heating and coating the surface of the cable core 7 through the coating equipment 6, so that the fire-resistant coating can quickly cover and adhere to the surface of the cable core 7.

[0037] The fourth step involves centering and thickness determination of cable core 7. Since the refractory coating is heated from the inside out, the side of the refractory coating closest to cable core 7 is cured first, while the side furthest from cable core 7 remains in a flowing state. Therefore, after passing through the centering sleeve 8, the excess refractory coating is scraped off by the centering sleeve 8. During the scraping process, the centering sleeve 8 simultaneously heats and cures the outer surface of the refractory coating, thereby achieving overall curing of the refractory coating. The centering sleeve 8 is used to position the axis of cable core 7 and limit the thickness of the refractory coating of cable core 7.

[0038] In the fifth step, the refractory coating is cured, and the cable core 7 after the thickness of the coating is completed enters the rear-end drying pipeline 9; the temperature of the rear-end drying pipeline 9 is 60-65℃; the cable core 7 is heated by the eddy current heater 5, and the heat is conducted by the cable core 7, and the cable core 7 and the refractory coating are fully roasted and cured by the external drying of the rear-end drying pipeline 9, so that a uniform and stable refractory coating is formed on the surface of the cable core 7; the refractory coating after the preliminary curing is secondarily cured by the rear-end drying pipeline 9.

[0039] The refractory coating is coated in 2-5 layers; each additional coating layer repeats the steps of the second to fourth steps once; the multi-coating method can reduce the thickness of single coating, so that the refractory coating can be better limited in thickness.

[0040] When the refractory coating is coated, the cross-roller coating is performed by the cross-roller coating unit 10, and the adjacent cross-roller coatings are staggered; when the cross-roller coating is used, the adjacent groups of cross-roller coatings are positioned with each other, which can prevent the axial center line of the cable core 7 from deviating from the coating center line; the refractory coating coating deviation is prevented, which causes the refractory coating to have inconsistent thickness distribution around the cable core 7.

[0041] The eddy current heater 5 is installed at the output end of the rear-end drying pipeline 9; the cable core 7 is heated and conducted by the eddy current heater 5, and the cable core 7 is heated and kept at 50-60℃ before entering the coating equipment 6 through heat conduction; the cable core 7 is heated and conducted by the eddy current heater 5, and the heat is conducted to the front-end coating equipment 6; after the cable core 7 is coated by the coating equipment 6, the refractory coating is separated from the coating equipment 6, and the refractory coating continuously approaches the eddy current heater 5 during the separation process; the closer to the eddy current heater 5, the higher the temperature of the cable core 7; the inner surface of the refractory coating can be quickly cured.

[0042] The temperature transmitter is arranged on the front side of the coating equipment 6 opposite to the cable core 7, and the temperature transmitter is linked with the eddy current heater 5 through the controller; the temperature of the cable core 7 is monitored by the temperature transmitter, and the heating temperature of the eddy current heater 5 is controlled according to the temperature, so that the cable core 7 entering the coating equipment 6 is kept at the set temperature.

[0043] Both the input end of the coating equipment 6 and the output end of the rear drying pipe 9 are equipped with cable core guide sleeves 11. The cable core guide sleeve 11 includes a frame base 12. A wheel seat 14 is slidably arranged on the inner side of the frame base 12 through a sliding column 13. A guide wheel 15 is rotatably arranged on the wheel seat 14. An adjusting bolt 16 passes through the frame base 12. The adjusting bolt 16 is movably embedded in the wheel seat 14 and fixed to the wheel seat 14. A tightening nut 17 is screwed onto both sides of the adjusting bolt 16. The cable core 7 guide sleeve 8 shell can be adjusted online. By rotating the adjusting bolt 16, the gap between adjacent guide wheels 15 can be adjusted, thereby enabling the positioning and rolling guidance of the cable core 7.

[0044] After the fire-resistant coating is completed, the cable core 7 enters the coating equipment 18, where a protective rubber layer 20 is coated on the outside of the fire-resistant coating. The protective rubber layer 20 has a thickness of 0.2~3mm and is applied by cross-shaped roller coating. After the protective rubber layer 20 is coated and cooled and shaped by the cooling equipment, it is sent to the winding equipment to wind the cable core 7. The protective rubber layer 20 can form a flexible protective support system on the surface of the fire-resistant coating, which can prevent the fire-resistant coating from being rubbed and scratched. The thickness of the protective rubber layer 20 can be determined according to the diameter of the tear-resistant rope 21.

[0045] The outer surface of the core-fixing sleeve 8 is wound with an electric heating wire 19; the electric heating wire 19 is covered with a heat insulation sleeve; the core-fixing sleeve 8 is heated by the electric heating wire 19, and the outer surface of the cable core 7 entering the core-fixing sleeve 8 is rapidly heated by the core-fixing sleeve 8, so as to quickly bake and fix the outer surface of the fire-resistant coating that has been completed to a fixed thickness; thereby enabling rapid curing of the microfluidic surface.

[0046] The above embodiments are merely preferred embodiments of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of the present invention are included within the scope of the present invention.

Claims

1. A high fire-resistant medium-voltage cable, characterized in that: The cable includes a cable core, the surface of which is processed and cured with a fire-resistant coating; protective rubber layers are spaced apart outside the fire-resistant coating, and tear-resistant ropes are arranged between the protective rubber layers; after the tear-resistant ropes are impregnated with rubber, they are deformed by applying pressure rollers and then attaching the tear-resistant ropes to the fire-resistant coating; the tear-resistant ropes are bonded to the fire-resistant coating; an outer sheath is wrapped around the protective rubber layers; the outer sheath fills the space between the tear-resistant ropes and the protective rubber layers.

2. The high fire-resistant medium-voltage cable according to claim 1, characterized in that: The outer cladding layer includes an inner cladding layer and an outer cladding layer; an electromagnetic shielding armor layer is disposed between the inner cladding layer and the outer cladding layer.

3. A processing method for a high fire-resistant coating on cables, used to process the fire-resistant coating of the high fire-resistant medium-voltage cable as described in claim 1, characterized in that, The production processes include the following: The first step is cleaning and drying. The cable core is cleaned using an ultrasonic cleaning device, then rinsed with a spray nozzle, and then air-dried using an air knife before entering the front-end drying pipe for further drying. The second step is internal heating of the cable core. After the cable core has been dried, it enters the eddy current heater and is heated by the eddy current heater. The third step is the application of the fire-resistant coating. After the cable core is heated and heat is conducted, it enters the coating equipment. The temperature of the cable core entering the coating equipment is maintained at 50~60℃. Then, the fire-resistant coating is applied to the surface of the cable core by heating and coating, so that the fire-resistant coating can quickly cover and adhere to the surface of the cable core. The fourth step is core positioning and thickness determination. Core positioning guide sleeves are installed at both the input end of the coating equipment and the output end of the rear drying pipe. Since the refractory coating is heated from the inside out, the side of the refractory coating closest to the cable core is cured first, while the side furthest from the cable core remains fluid. Therefore, after passing through the core positioning sleeve, excess refractory coating is scraped off. During the scraping process, the core positioning sleeve simultaneously heats and cures the outer surface of the refractory coating. The core positioning sleeve is used to position the cable core axis and limit the thickness of the refractory coating on the cable core. The fifth step is the curing of the fire-resistant coating. After the coating thickness is fixed, the cable core enters the rear drying pipe. The temperature of the rear drying pipe is 60~65℃. The cable core is heated by the eddy current heater, and the heat is conducted through the cable core and dried by the outside of the rear drying pipe. The cable core and the fire-resistant coating are thoroughly baked and cured, forming a uniform and stable fire-resistant coating on the surface of the cable core. Step 6: After the fire-resistant coating is completed, the cable core enters the gluing equipment, where strip-shaped protective rubber layers are applied to the outside of the fire-resistant coating at intervals.

4. The processing technology of the high fire-resistant coating for cables according to claim 3, characterized in that: The refractory coating has 2 to 5 layers; for each additional layer, steps 2 to 4 are repeated.

5. The processing technology of the high fire-resistant coating for cables according to claim 4, characterized in that: When applying the refractory coating, a cross-shaped roller coating is used, and adjacent cross-shaped roller coatings are staggered.

6. The processing technology of the high fire-resistant coating for cables according to claim 3, characterized in that: The eddy current heater is installed at the output end of the rear drying pipe; the eddy current heater heats and conducts heat to the cable core, and the cable core is heated to 50~60℃ before entering the coating equipment through heat conduction.

7. The processing technology of the high fire-resistant coating for cables according to claim 3, characterized in that: A temperature transmitter is arranged on the front side of the coating equipment, directly facing the cable core. The temperature transmitter is linked to the eddy current heater via a controller.

8. The processing technology of the high fire-resistant coating for cables according to claim 3, characterized in that: The cable core guide sleeve includes a frame base, a wheel seat is slidably arranged on the inner side of the frame base via a sliding column, a guide wheel is rotatably arranged on the wheel seat, an adjusting bolt passes through the frame base, the adjusting bolt is movably embedded into the wheel seat and fixed to the wheel seat, and a tightening nut is screwed onto both sides of the adjusting bolt.

9. The processing technology of the high fire-resistant coating for cables according to claim 3, characterized in that: The protective rubber layer has a thickness of 0.2~3mm and is coated in a cross shape by roller. After the protective rubber layer is coated by roller and cooled and shaped by a cooling device, it is sent to a winding device to wind the cable core.

10. The processing technology of the high fire-resistant coating for cables according to claim 3, characterized in that: The outer surface of the core sleeve is wound with an electric heating wire; the electric heating wire is covered with a heat insulation sleeve.

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