High-fire-resistant medium-voltage cable and processing technology of high-fire-resistant coating of cable

Abstract

The invention 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. Comprising a cable core, and a fireproof coating is processed and cured on the surface of the cable core; protective rubber layers are arranged outside the fireproof coating at intervals, and anti-tearing pull ropes are arranged between the protective rubber layers; after the tear-resistant pull rope is impregnated, the tear-resistant pull rope is deformed under the pressure of a pressing wheel, and the tear-resistant pull rope is attached to the fireproof coating; the tear-resistant pull rope is bonded with the fire-resistant coating; the outer part of the protective rubber layer is coated with an outer coating layer; the outer wrapping layer is filled between the outer part of the anti-tearing pull rope and the protective rubber layer; according to the high-fire-resistance medium-voltage cable and the processing technology of the high-fire-resistance coating of the cable, the cable coated with the fire-resistance coating can be independently processed and rolled, the fire-resistance coating cannot be abraded, and in addition, the distribution thickness of the fire-resistance coating on the circumferential surface of the cable core can be more uniform.

Description

Technical Field

[0001] The invention specifically relates to a high fire-resistant medium-voltage cable and a processing technology for a cable high fire-resistant coating, and belongs to the technical field of high fire-resistant cable production. Background Art

[0002] Medium voltage cables must use cross-linked polyethylene insulation, which has poor high temperature resistance. In order to make medium voltage cables fire-resistant, a protective shell must be added to the insulation core to prevent flames and heat from entering the cable, so that the medium voltage cables have fire-resistant properties. At present, the fire-resistant structure of medium voltage fire-resistant cables on the market consists of a thermal insulation layer and a fire barrier layer from the inside to the outside, and the thickness of the thermal insulation layer and the fire barrier layer is relatively thick, which increases the outer diameter and weight of the cable, making the installation and laying of the cable more difficult. More importantly, the fire barrier layer will hinder the heat dissipation of the cable and affect the current carrying capacity of the cable. For this reason, China Patent Publication No.: CN116072356A discloses a high fire-resistant A processing technology for medium voltage cables and cable high fire-resistant coatings, wherein the high fire-resistant coating is produced in series with the cable outer sheath. The processing technology for the high fire-resistant coating of the cable and the high fire-resistant medium voltage cable made therefrom, in which the high fire-resistant coating and the outer sheath are produced in series, can meet the fire resistance requirements of the medium voltage cable. When processing the existing medium voltage cables, if one production line is used to directly complete the cable production, it is easy to affect the cable production efficiency. If the fire-resistant coating and the outer sheath are produced separately, the cable core will be rolled up after production, which is easy to cause wear of the fire-resistant coating and lead to failure of fire-resistant protection. In addition, when processing the fire-resistant coating of the existing cable core, it is easy to cause the cable core to be eccentric, resulting in inconsistent thickness on the circumference of the cable core. Summary of the invention

[0003] To solve the above problems, the present invention proposes a processing technology for high-fire-resistant medium-voltage cables and cable high-fire-resistant coatings, which can be used to individually process and roll cables coated with a cured fire-resistant coating without causing wear of the fire-resistant coating. In addition, the thickness of the fire-resistant coating can be more evenly distributed around the cable core.

[0004] The high fire-resistant medium-voltage cable of the present invention comprises a cable core, the surface of which is processed by a processing technology of a high fire-resistant coating of the cable to obtain a fire-resistant coating; it also comprises a tear-resistant pull rope arranged between protective rubber layers; after the tear-resistant pull rope is dipped in glue, the tear-resistant pull rope is pressed and filled between the protective rubber layers by a pressing wheel, and the tear-resistant pull rope is deformed by the pressure of the pressing wheel, so that the tear-resistant pull rope is fully fitted to the surface of the cable core; the tear-resistant pull rope is bonded to the fire-resistant coating; the protective rubber layer is coated with an outer sheath; the outer sheath is filled between the outside of the tear-resistant pull rope and the protective rubber layer, the tear-resistant pull rope is simple and convenient to install, and the tear-resistant pull rope and the cable core can be quickly installed.

[0005] Furthermore, the outer covering layer includes an inner covering layer and an outer covering layer; an electromagnetic shielding armor layer is arranged between the inner covering layer and the outer covering layer, and electromagnetic shielding is achieved through the electromagnetic shielding armor layer. At the same time, in combination with the tear-resistant pull rope, the structural strength of the cable can be enhanced.

[0006] The processing technology of the cable high fire-resistant coating of the present invention is used to process the fire-resistant coating of the high fire-resistant medium voltage cable, and includes the following production process: The first step is cleaning and drying. The cable core is cleaned by ultrasonic cleaning equipment, then rinsed by a spray head. After rinsing, it is air-dried by an air knife, and then enters the front-end drying pipeline for drying; The second step is to heat the cable core internally. The cable core that has completed drying enters the eddy current heater and is heated by the eddy current heater. The third step is to coat the refractory 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°C. Then, the refractory coating is heated and coated on the surface of the cable core through the coating equipment, so that the refractory coating is quickly coated and bonded to the surface of the cable core. The fourth step is to fix the core and thickness of the cable core. Since the refractory coating is heated from the inside to the outside, the refractory coating is first cured on the side close to the cable core, and the side away from the cable core is still in a flowing state. Therefore, after passing through the core fixing sleeve, the excess refractory coating is scraped off by the core fixing sleeve; during the scraping process, the core fixing sleeve heats and cures the outer surface of the refractory coating simultaneously, thereby achieving the overall curing of the refractory coating; the core fixing sleeve is used to locate the cable core axis and limit the thickness of the refractory coating of the cable core; The fifth step is to cure the refractory coating. The cable core that has completed the coating thickness treatment enters the rear-end drying pipeline. The temperature of the rear-end drying pipeline is 60~65℃. The cable core is heated by the eddy current heater, and the heat is conducted by the cable core. The cable core and the refractory coating are fully baked and cured through external drying in the rear-end drying pipeline, forming a uniform and stable refractory coating on the surface of the cable core. The refractory coating that has completed the initial curing is secondary cured through the rear-end drying pipeline. In the sixth step, after the cable core is processed with the fire-resistant coating, the cable core enters the glue coating equipment, and a strip-shaped protective rubber layer is coated on the outside of the fire-resistant coating at intervals through the glue coating equipment.

[0007] Furthermore, the number of coating layers of the refractory coating is 2 to 5; each time an additional layer is coated, the second to fourth steps are repeated; the use of a multi-pass coating method can reduce the thickness of a single coating, thereby enabling the thickness of the refractory coating to be better limited.

[0008] Furthermore, when the refractory coating is applied, a cross-shaped roller is used, and adjacent cross-shaped rollers are staggered; when a cross-shaped roller is used, adjacent groups of cross-shaped rollers are positioned relative to each other, which can prevent the cable core axis from deviating from the coating center line; and prevent the refractory coating from deviating, resulting in inconsistent thickness of the refractory coating on the circumference of the cable core.

[0009] Furthermore, the eddy current heater is installed at the output end of the rear-end drying pipeline; the cable core is heated and heat-conducted by the eddy current heater, and the temperature of the cable core is heated and maintained at 50-60°C before entering the coating equipment by heat conduction; the cable core is heated and heat-conducted by the eddy current heater, and the heat is transferred 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. During the separation process, the refractory coating continues to approach the eddy current heater, and the closer to the eddy current heater, the higher the temperature of the cable core; the inner surface of the refractory coating can be quickly solidified.

[0010] Furthermore, a temperature transmitter is arranged on the front side of the coating equipment facing the cable core, and the temperature transmitter is linked to the eddy current heater through a controller; the cable core temperature is monitored by the temperature transmitter, and the heating temperature of the eddy current heater is controlled according to the temperature, so that the cable core enters the coating equipment and is maintained at the set temperature.

[0011] Furthermore, the coating equipment input end and the rear-end drying pipe output end are both equipped with a cable core positioning guide sleeve; 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 sliding column, a guide wheel is rotatably arranged on the wheel seat, an adjusting bolt passes through the frame seat, the adjusting bolt is movably embedded in the wheel seat and fixed to the wheel seat, and the adjusting bolt is screwed with tightening nuts on both sides of the frame seat; the cable core positioning sleeve shell is adjusted online, and the gap between adjacent guide wheels is adjusted by rotating the adjusting bolt, so that the cable core can be positioned and guided for walking and rolling.

[0012] Furthermore, after the cable core is processed with the fire-resistant coating, the cable core enters the glue coating equipment, and a protective rubber layer is coated on the outside of the fire-resistant coating by the glue 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, it is sent to the winding equipment to wind the cable core; a flexible protective support system can be formed on the surface of the fire-resistant coating through the protective rubber layer, which can prevent the fire-resistant coating from being scratched by friction; the thickness of the protective rubber layer can be determined according to the diameter of the tear-resistant pull rope.

[0013] Furthermore, an electric heating wire is wound around the outer surface of the core fixing sleeve; the electric heating wire is coated with an insulating sleeve on the outside; the core fixing sleeve is heated by the electric heating wire, and the outside of the cable core entering the core fixing sleeve is quickly heated by the core fixing sleeve, so as to achieve rapid baking and fixing of the outer surface of the refractory coating with a fixed thickness; thereby, the microfluidic surface can be quickly solidified.

[0014] Compared with the prior art, the processing technology of the high fire-resistant medium voltage cable and the high fire-resistant coating of the cable of the present invention can individually process and roll the cable coated with the solidified fire-resistant coating, and through the protection of the protective rubber layer, the adjacent cable cores after rolling are isolated from each other by the protective rubber layer; the fire-resistant coatings will not contact each other, which can protect the fire-resistant coating and will not cause wear of the fire-resistant coating. In addition, adjacent protective rubber layers form grooves; the arrangement and installation guide of the tear-resistant pull rope can be facilitated; the tear-resistant pull rope can be prevented from being separated from the installation position; the cable installation is more convenient; in addition, the adjacent cable cores are positioned by the core-fixing guide sleeves, the thickness is determined by the core-fixing sleeves, and the positioning is carried out by the cross-shaped roller coating, so that the thickness of the fire-resistant coating on the circumference of the cable core can be more evenly distributed. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of the gluing equipment of the present invention coating a protective rubber layer on a cable core.

[0016] Figure 2 The figure is a schematic diagram of the processing process of the high fire-resistant coating for cables of the present invention.

[0017] Figure 3 This is a schematic diagram of the coating line structure of the cable high fire-resistant coating of the present invention.

[0018] Figure 4 For the present invention Figure 3 Schematic diagram of the local enlarged structure at point A in the middle.

[0019] Figure 5 It is a schematic diagram of the production line structure for completing the second to fourth steps of the production process of the present invention.

[0020] Figure 6 It is a schematic diagram of the structure of the cable core positioning guide sleeve of the present invention.

[0021] Figure 7 It is a schematic diagram of the coating structure of the cable core by the cross roller coating unit of the present invention.

[0022] Figure 8 This is a schematic diagram of the structure of the cross roller coating unit of the present invention coating the cable core with a fire-resistant coating.

[0023] Figure numerals: 1. Ultrasonic cleaning equipment, 2. Spray head, 3. Air knife, 4. Front drying pipe, 5. Eddy current heater, 6. Coating equipment, 7. Cable core, 8. Core fixing sleeve, 9. Rear drying pipe, 10. Cross roller coating unit, 11. Cable core core fixing guide sleeve, 12. Frame seat, 13. Sliding column, 14. Wheel seat, 15. Guide wheel, 16. Adjusting bolt, 17. Tightening nut, 18. Gluing equipment, 19. Heating wire, 20. Protective rubber layer, 21. Tear-resistant pull rope, 22. Outer layer. DETAILED DESCRIPTION

[0024] Example: like Figure 1 The high fire-resistant medium-voltage cable shown comprises a cable core 7, the surface of which is provided with a fire-resistant coating, and the outside of which is provided with a rubber layer 20 at intervals; it also comprises a tear-resistant pull rope 21 arranged between the protective rubber layers 20; after the tear-resistant pull rope 21 is dipped in glue, the tear-resistant pull rope 21 is pressed and filled between the protective rubber layers 20 by a pressing wheel, and the tear-resistant pull rope 21 is deformed by the pressure of the pressing wheel, so that the tear-resistant pull rope 21 is fully fitted with the surface of the cable core 7; the tear-resistant pull rope 21 is bonded to the fire-resistant coating; the outside of the protective rubber layer 20 is coated with an outer sheath 22; the outer sheath 22 is filled between the outside of the tear-resistant pull rope 21 and the protective rubber layer 20, the tear-resistant pull rope 21 is simple and convenient to install, and the tear-resistant pull rope 21 and the cable core 7 can be quickly installed.

[0025] The outer covering layer 22 includes an inner covering layer and an outer covering layer; an electromagnetic shielding armor layer is arranged between the inner covering layer and the outer covering layer, and electromagnetic shielding is achieved through the electromagnetic shielding armor layer. At the same time, in conjunction with the tear-resistant pull rope 21, the structural strength of the cable can be enhanced.

[0026] like Figures 2 to 8 The processing technology of the cable high fire resistant coating shown includes the following production processes: The first step is cleaning and drying. The cable core 7 is cleaned by an ultrasonic cleaning device 1, and then rinsed by a spray head 2. After the rinsing is completed, it is air-dried by an air knife 3, and then enters the front drying pipeline 4 for drying; In the second step, the cable core 7 is internally heated, and the cable core 7 that has completed drying enters the eddy current heater 5, and the cable core 7 is heated by the eddy current heater 5; The third step is to coat the refractory coating. After the cable core 7 is heated and heat is conducted, it enters the coating device 6. The temperature of the cable core 7 entering the coating device 6 is maintained at 50-60°C. Then, the refractory coating is heated and coated on the surface of the cable core 7 by the coating device 6, so that the refractory coating is quickly coated and bonded to the surface of the cable core 7. The fourth step is to fix the core and thickness of the cable core 7. Since the refractory coating is heated from the inside to the outside, the refractory coating is first solidified on the side close to the cable core 7, and the side away from the cable core 7 is still in a flowing state. Therefore, after passing through the core fixing sleeve 8, the excess refractory coating is scraped off by the core fixing sleeve 8; during the scraping process, the core fixing sleeve 8 heats and cures the outer surface of the refractory coating simultaneously, thereby achieving the overall solidification of the refractory coating; the axial centerline of the cable core 7 is positioned and the thickness of the refractory coating of the cable core 7 is limited by the core fixing sleeve 8; The fifth step is to cure the refractory coating. The cable core 7 that has completed the coating thickness treatment enters the rear-end drying pipe 9; the temperature of the rear-end drying pipe 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 dried externally by the rear-end drying pipe 9 to fully bake and cure the cable core 7 and the refractory coating, forming a uniform and stable refractory coating on the surface of the cable core 7; the refractory coating that has completed the initial curing is secondary cured by the rear-end drying pipe 9.

[0027] The number of coating layers of the refractory coating is 2 to 5; each time an additional layer is coated, the second to fourth steps are repeated; the use of a multi-pass coating method can reduce the thickness of a single coating, thereby enabling the thickness of the refractory coating to be better limited.

[0028] When the refractory coating is applied, a cross-shaped roller coating is performed by a cross-shaped roller coating unit 10, and adjacent cross-shaped roller coatings are arranged in a staggered manner; when cross-shaped roller coating is adopted, adjacent groups of cross-shaped roller coatings are positioned with each other, which can prevent the axis center line of the cable core 7 from deviating from the coating center line; and prevent the refractory coating from deviating from the coating, resulting in inconsistent distribution thickness of the refractory coating on the circumference of the cable core 7.

[0029] The eddy current heater 5 is installed at the output end of the rear drying pipe 9; the cable core 7 is heated and heat-conducted by the eddy current heater 5, and the temperature of the cable core 7 is heated and maintained at 50-60°C before entering the coating device 6 by heat conduction; the cable core 7 is heated and heat-conducted by the eddy current heater 5, and the heat is transferred to the front coating device 6 by heat conduction. After the cable core 7 is coated by the coating device 6, the refractory coating separates from the coating device 6. During the separation process, the refractory coating continues to approach the eddy current heater 5, and 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 solidified.

[0030] A temperature transmitter is arranged on the front side of the coating device 6 facing the cable core 7, and the temperature transmitter is linked to the eddy current heater 5 through a 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 enters the coating device 6 and is maintained at the set temperature.

[0031] The input end of the coating equipment 6 and the output end of the rear-end drying pipe 9 are both installed with a cable core positioning guide sleeve 11; the cable core positioning guide sleeve 11 includes a frame seat 12, and a wheel seat 14 is slidably arranged on the inner side of the frame seat 12 through a sliding column 13, and a guide wheel 15 is rotatably arranged on the wheel seat 14, and an adjusting bolt 16 passes through the frame seat 12, and the adjusting bolt 16 is movably embedded in the wheel seat 14 and fixed to the wheel seat 14, and the adjusting bolt 16 is screwed with a tightening nut 17 on both sides of the frame seat 12; the cable core 7 core positioning sleeve 8 shell is adjusted online, and the gap between adjacent guide wheels 15 is adjusted by rotating the adjusting bolt 16, so that the cable core 7 can be positioned and guided for walking and rolling.

[0032] After the cable core 7 is processed with the fire-resistant coating, the cable core 7 enters the glue coating equipment 18, and the protective rubber layer 20 is coated on the outside of the fire-resistant coating by the glue coating equipment 18; the thickness of the protective rubber layer 20 is 0.2~3mm, and the protective rubber layer 20 is cross-shaped roller coated; after the protective rubber layer 20 is roller-coated and cooled and shaped by the cooling equipment, it is sent to the winding equipment to roll 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 scraped by friction; the thickness of the protective rubber layer 20 can be determined according to the wire diameter of the tear-resistant pull rope 21.

[0033] The outer surface of the core fixing sleeve 8 is wrapped with an electric heating wire 19; the outside of the electric heating wire 19 is covered with an insulating sleeve; the core fixing sleeve 8 is heated by the electric heating wire 19, and the outside of the cable core 7 entering the core fixing sleeve 8 is quickly heated by the core fixing sleeve 8, so as to achieve rapid baking and fixing of the outer surface of the refractory coating with a fixed thickness; thereby, the microfluid surface can be quickly solidified.

[0034] The above embodiments are only preferred implementations of the present invention, so any equivalent changes or modifications made according to the structures, features and principles described in the scope of application of the present invention are included in the scope of application of the present invention.

Claims

1. A highly fire-resistant medium voltage cable, characterized in that: It comprises a cable core, the surface of which is processed and cured with a fire-resistant coating; a protective rubber layer is arranged at intervals outside the fire-resistant coating, and tear-resistant drawstrings are arranged between the protective rubber layers; after the tear-resistant drawstrings are dipped in glue, they are deformed by applying pressure through a pressure wheel, and the tear-resistant drawstrings are attached to the fire-resistant coating; the tear-resistant drawstrings are bonded to the fire-resistant coating; the protective rubber layer is coated with an outer covering layer; the outer covering layer is filled between the outside of the tear-resistant drawstrings and the protective rubber layer.

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

3. A process for processing a high fire-resistant coating of a cable, used for processing the fire-resistant coating of the high fire-resistant medium voltage cable according to claim 1, characterized in that: The production process includes the following: The first step is cleaning and drying. The cable core is cleaned by ultrasonic cleaning equipment, then rinsed by a spray head. After rinsing, it is air-dried by an air knife, and then enters the front-end drying pipeline for drying; The second step is to heat the cable core internally. The cable core that has completed drying enters the eddy current heater and is heated by the eddy current heater. The third step is to coat the refractory 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°C. Then, the refractory coating is heated and coated on the surface of the cable core through the coating equipment, so that the refractory coating is quickly coated and bonded to the surface of the cable core. The fourth step is to fix the core and thickness of the cable core. Since the refractory coating is heated from the inside to the outside, the refractory coating is first solidified on the side close to the cable core, and the side away from the cable core is still in a fluid state. Therefore, after passing through the core fixing sleeve, the excess refractory coating is scraped off by the core fixing sleeve; during the scraping process, the outer surface of the refractory coating is heated and cured simultaneously; the core fixing sleeve is used to locate the cable core axis and limit the thickness of the refractory coating of the cable core; The fifth step is to cure the refractory coating. The cable core that has completed the coating thickness treatment enters the rear-end drying pipeline. The temperature of the rear-end drying pipeline is 60~65℃. The cable core is heated by the eddy current heater, and the heat is conducted by the cable core. The cable core and the refractory coating are fully baked and cured through external drying in the rear-end drying pipeline, forming a uniform and stable refractory coating on the surface of the cable core. In the sixth step, after the cable core is processed with the fire-resistant coating, the cable core enters the glue coating equipment, and a strip-shaped protective rubber layer is coated on the outside of the fire-resistant coating at intervals through the glue coating equipment.

4. The processing technology of the cable high fire-resistant coating according to claim 3 is characterized in that: The number of coating layers of the refractory coating is 2 to 5; each time one more layer is coated, the second to fourth steps are repeated.

5. The processing technology of the cable high fire-resistant coating according to claim 4 is characterized in that: When the refractory coating is applied, a cross-shaped roller is used, and adjacent cross-shaped rollers are arranged in a staggered manner.

6. The processing technology of the cable high fire-resistant coating according to claim 3 is characterized by: The eddy current heater is installed at the output end of the rear drying pipeline; the cable core is heated and heat-conducted by the eddy current heater, and the temperature of the cable core is heated and maintained at 50-60° C. before entering the coating equipment through heat conduction.

7. The processing technology of the cable high fire-resistant coating according to claim 3 is characterized by: A temperature transmitter is arranged on the front side of the coating device facing the cable core, and the temperature transmitter is linked with the eddy current heater through a controller.

8. The processing technology of the cable high fire-resistant coating according to claim 3 is characterized by: The input end of the coating equipment and the output end of the rear-end drying pipe are both equipped with a cable core positioning guide sleeve; the cable core positioning guide sleeve includes a frame seat, a wheel seat is slidably arranged on the inner side of the frame seat through a sliding column, a guide wheel is rotatably arranged on the wheel seat, an adjusting bolt passes through the frame seat, the adjusting bolt is movably embedded in the wheel seat and fixed to the wheel seat, and the adjusting bolt is screwed with tightening nuts on both sides of the frame seat.

9. The processing technology of the cable high fire-resistant coating according to claim 3 is characterized by: The thickness of the protective rubber layer is 0.2-3 mm, and the protective rubber layer is coated by a cross-shaped roller. After the protective rubber layer is coated by roller and cooled and shaped by a cooling device, it is sent to a coiling device to coil the cable core.

10. The processing technology of the cable high fire-resistant coating according to claim 3 is characterized by: The outer surface of the fixed core sleeve is wound with a heating wire; the outer surface of the heating wire is covered with a heat insulation sleeve.

Images