A reinforced rubber sheathed flexible cable for a ladle car and a manufacturing method thereof

Abstract

The present application relates to the technical field of metallurgical special cable, especially to a reinforced rubber sheath flexible cable for ladle car and a manufacturing method thereof, which comprises at least three power supply main wire cores, at least one grounding wire core and at least two control wire cores, the insulation outer diameter of the grounding wire core is the same as that of the power supply main wire core to form a four equal core structure, the control wire core is arranged in the cable core gap, the cable core center is provided with a kevlar filament bundle tensile reinforcing filler strip, and the cable core is sequentially provided with a cabling tape, a sheath, a double-layer fluorine mica tape first protective layer and a galvanized steel wire woven second protective layer. The present application realizes the comprehensive performance of stable cable structure, high tensile resistance and high temperature resistance and splash prevention through the synergistic protection of the four equal core structure, the gap control wire core, the center kevlar filament bundle and the fire-resistant protective layer and the steel wire woven layer.

Description

Technical Field

[0001] This invention relates to the field of metallurgical special cable technology, and in particular to a reinforced rubber-sheathed flexible cable for steel ladle cars and its manufacturing method. Background Technology

[0002] Steel ladle car cables are special cables designed for the metallurgical industry, specifically for the power, control, and signal transmission of steel ladle transfer cars in steel plants. They belong to the high-reliability cable sub-segment for high-temperature, heavy-load, and dynamic operating conditions. Primarily used in steel plants and metallurgical plants for equipment such as steel ladle cars and slag ladle trolleys, they provide power and control signal transmission for the transfer and unloading of steel ladles, making them indispensable components in continuous casting and converter steelmaking processes. Their technological development revolves around three extreme operating conditions: First, high-temperature heat radiation and splashing. Molten steel temperatures can reach over 1000℃, requiring cables to withstand close-range high-temperature radiation and ambient temperatures consistently above 60℃, with the risk of being scorched by slag and sparks. Conventional cables are prone to sheath melting, aging, and cracking. Second, dynamic mechanical stress. Cables are continuously wound and unwound through drums and towed sections, enduring high-frequency bending, dragging, torsion, and stretching, leading to core breakage and sheath wear. Third, harsh environmental corrosion. Dust, oil, corrosive gases, and humid environments accelerate sheath aging and reduce insulation performance.

[0003] Under the aforementioned operating conditions, existing traditional cables lack sufficient high-temperature resistance and splash resistance, leading to frequent short-circuit shutdowns caused by insulation melting and sheath cracking. Their mechanical performance is also significantly weak, with core strand breakage and sheath wear resulting in an average lifespan of less than three months. Furthermore, they exhibit poor environmental adaptability, with a significantly higher failure rate in humid environments. Therefore, providing a high-temperature resistant, tensile- and abrasion-resistant, and structurally stable cable specifically for steel ladle vehicles is a pressing technical problem that needs to be solved in this field. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the existing steel ladle car cables have insufficient high temperature resistance and splash resistance under high temperature and heavy load dynamic conditions, poor mechanical properties leading to core wire breakage and sheath wear, and the traditional cable structure is unstable, with a large outer diameter and insufficient tensile strength.

[0005] The technical solution adopted by this invention to solve its technical problem is: a reinforced rubber-sheathed flexible cable for steel ladle cars, comprising at least three main power supply cores, at least one grounding core, and at least two control cores; the main power supply cores include a main core conductor and a main core insulation layer, the grounding cores include a ground core conductor and a ground core insulation layer, and the control cores include a control core conductor and a control core insulation layer; the thickness of the ground core insulation layer is greater than the thickness of the main core insulation layer, making the outer diameter of the grounding core insulation equal to the outer diameter of the main power supply core insulation, forming a four-core structure; after cabling, the control cores are located after the main power supply cores and grounding cores are cabled together. There is no filling material inside the cable core in the gaps; the center of the cable core is provided with a tensile reinforcing filler strip, which includes aramid yarn bundles and a filler strip outer sheath covering the outer periphery of the aramid yarn bundles. The aramid yarn bundles are made of at least three 2500D aramid yarns twisted together; the cable core is wrapped with a cable wrapping tape; the cable wrapping tape is covered with a sheath; a first protective layer is provided outside the sheath, which is made of double-layer fluorophlogopite mica tape, with an overlap rate of 35% to 45% for each layer of fluorophlogopite mica tape; a second protective layer is provided outside the first protective layer, which is made of galvanized steel wire woven on the outer surface of the first protective layer, with a weaving density of 40% to 45%.

[0006] Furthermore, the sheath is made of heat-resistant, low-smoke, halogen-free ethylene-vinyl acetate rubber extrusion molding at 125℃.

[0007] Furthermore, the main conductor, ground conductor, and control conductor all use Category 6 tin-plated copper stranded conductors; the insulation layers of the main conductor, ground conductor, and control conductor are all made of heat-resistant 125℃ EPDM rubber extrusion.

[0008] Furthermore, the present invention also provides a method for manufacturing a reinforced rubber-sheathed flexible cable for steel ladle cars, comprising the following steps: S1, forming a main conductor, a ground conductor, and a control conductor from six types of tin-plated copper stranded conductors, and extruding a layer of heat-resistant 125°C EPDM rubber to form an insulation layer on the outside of each conductor; wherein the extrusion thickness of the ground conductor insulation layer is greater than the extrusion thickness of the main conductor insulation layer, so that the outer diameter of the ground conductor insulation is equal to the outer diameter of the power supply main conductor insulation; S2, stranding at least three power supply main conductors and at least one ground conductor into a cable. Simultaneously, at least two control cores are placed in the gaps between the cable cores, and a tensile reinforcing filler strip is placed in the center of the cable core; S3, high-temperature resistant polyester tape is wrapped around the cable core after cabling to form a cabling wrapping tape; S4, a layer of heat-resistant 125℃ low-smoke halogen-free ethylene-vinyl acetate rubber is extruded and wrapped around the cabling wrapping tape to form a sheath; S5, a first protective layer is formed by wrapping the sheath with double-layer fluorophlogopite mica tape, with an overlap rate of 35% to 45% for each layer; S6, a second protective layer is formed by weaving galvanized steel wire on the outer surface of the first protective layer, with a weaving density of 40% to 45%.

[0009] The beneficial effects of this invention are as follows: the conductor uses a flexible Category 6 tin-plated copper stranded conductor, and the insulation layer uses heat-resistant 125℃ EPDM rubber, which has excellent resistance to repeated bending and fracture, making it suitable for steel ladle car drum dragging conditions; the grounding core insulation is thickened to form a four-core structure, and the control core is placed in the edge gap without the need for filler material, resulting in a stable cable structure and a small outer diameter; the tensile strength of the aramid fiber bundle in the cable core is about five to six times that of steel wire of the same diameter, significantly improving the overall tensile, bending, and drag resistance performance; the double-layer fluoropolymer mica tape first protective layer can maintain the normal operation of the cable under fire temperatures of 750℃ to 950℃, preventing damage from steel slag sparks; the galvanized steel wire braided second protective layer forms a mesh protection for the mica tape, preventing the mica tape from falling off and sliding, and from being hit or bumped by external heavy objects, with fire resistance and mechanical protection working in synergy; the sheath uses low-smoke halogen-free materials, which do not release toxic fumes when burning. The synergistic cooperation of each structural layer gives the cable excellent comprehensive performance under high temperature, heavy load, and dynamic working conditions. Attached Figure Description

[0010] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0011] Figure 1 This is a schematic diagram of the cable cross-section structure of the present invention.

[0012] Explanation of reference numerals in the attached drawings: 100. Main power supply core; 110. Main core conductor; 120. Main core insulation layer; 200. Grounding core; 210. Ground conductor; 220. Ground insulation layer; 300. Control core; 310. Control conductor; 320. Control insulation layer; 400. Tensile reinforcing filler strip; 410. Aramid filament bundle; 420. Filler strip outer sheath; 500. Cable wrapping tape; 600. Sheath; 700. First protective layer; 800. Second protective layer. Detailed Implementation

[0013] like Figure 1 As shown in the figure, this embodiment provides a reinforced rubber-sheathed flexible cable for ladle cars, comprising three main power supply cores 100, one grounding core 200, and two control cores 300. The main power supply core 100 includes a main conductor 110 and an outer main conductor insulation layer 120; the grounding core 200 includes a ground conductor 210 and an outer ground conductor insulation layer 220; and the control cores 300 include a control conductor 310 and an outer control conductor insulation layer 320.

[0014] The main conductor 110, ground conductor 210, and control conductor 310 are all made of Category 6 tin-plated copper stranded conductors, which are flexible, have a small bending radius, are resistant to repeated bending fatigue, are fracture-resistant, and have uniform heat dissipation. The main conductor insulation layer 120, ground conductor insulation layer 220, and control conductor insulation layer 320 are all made of heat-resistant 125℃ EPDM rubber by extrusion, which has excellent electrical insulation performance and can be used continuously for a long time at a conductor operating temperature of 125℃. It can withstand 150℃ to 200℃ for short periods. It also has the advantages of heat aging resistance, ozone resistance, weather resistance, acid and alkali resistance, steam resistance, and low density.

[0015] The thickness of the grounding core insulation layer 220 is greater than that of the main core insulation layer 120, making the outer diameter of the grounding core 200 the same as that of the main power supply core 100. Taking the cable specification 3×50+1×25+4×4 as an example, the main power supply core 100 has a cross-section of 50mm², a conductor outer diameter of 10.0mm, an insulation thickness of 1.4mm, and an insulation outer diameter of 12.8mm; the grounding core 200 has a cross-section of 25mm², and its insulation outer diameter is 9.2mm when the standard insulation thickness is 1.2mm. By increasing the extrusion thickness of the grounding core insulation layer 220 to 3.0mm, the outer diameter of the grounding core 200 also reaches 12.8mm, consistent with the main power supply core 100, forming a stable four-core structure and ensuring the structural stability of the cable after cabling.

[0016] Two control conductors 300 are positioned within the gap formed by the cabling of three main power supply conductors 100 and one grounding conductor 200, arranged in a 4×4 configuration according to cable specifications. Because the control conductors 300 are located in the gap, no additional filler material is needed to ensure cable structural stability, while also reducing the outer diameter of the finished cable. A tensile reinforcing filler strip 400 is placed at the center of the cable core. This tensile reinforcing filler strip 400 comprises an aramid filament bundle 410 composed of five 2500D aramid filaments twisted together and a filler strip sheath 420 covering the aramid filament bundle 410. The filler strip sheath 420 is made of heat-resistant, 125℃ low-smoke, halogen-free ethylene-vinyl acetate rubber extrusion. Aramid filaments have extremely high strength, with a tensile strength approximately five to six times that of steel wire of the same diameter, providing overall cable tensile strength, bending resistance, and drag resistance, while also offering advantages such as high-temperature resistance, aging resistance, and ultra-light weight.

[0017] After cabling, the cable core is first wrapped with a high-temperature resistant polyester tape as the cabling wrapping tape 500 to fix the relative positions of the cores and prevent loosening. Outside the cabling wrapping tape 500, a layer of heat-resistant, low-smoke, halogen-free ethylene-vinyl acetate rubber 600 is extruded and wrapped. This sheath can be used for extended periods at ambient temperatures up to 60℃ and features low smoke, halogen-free properties, strong weather resistance, excellent chemical stability, and superior mechanical properties. Outside the sheath 600, a first protective layer 700 is formed by wrapping with double layers of fluorophlogopite mica tape, with the overlap rate of each layer controlled between 35% and 45%. Fluoropite mica tape has excellent fire resistance; the conventional fire resistance test temperature for cables is 750℃ to 950℃, and the cable can operate normally at this temperature. The first protective layer 700 mainly prevents steel slag and sparks from scorching the cable and damaging the sheath and insulation layers.

[0018] A second protective layer 800 is formed on the outer surface of the first protective layer 700 by galvanized steel wire braiding, with a braiding density controlled between 40% and 45%. This layer primarily provides mesh protection for the fluorophlogopite tape, preventing it from detaching or slipping. It also protects the cable from damage caused by impacts or collisions from external heavy objects. The second protective layer 800 is located on the outermost layer of the cable. The galvanized steel wire braided mesh of the second protective layer 800, together with the double-layer fluorophlogopite tape of the first protective layer 700, constitutes a dual-layer protection system that combines fire resistance and mechanical protection. The steel wire braided mesh withstands mechanical impact while restraining the mica tape, keeping it wrapped. The mica tape maintains its fire resistance integrity during high-temperature fire supply. Together, these two elements ensure long-term reliable operation of the cable under the conditions of high-temperature splashes and mechanical impacts encountered in ladle car applications.

[0019] The manufacturing method of this cable includes the following steps: S1, making 6 types of tin-plated copper stranded conductors into main conductor 110, ground conductor 210 and control conductor 310 respectively, and extruding a layer of heat-resistant 125℃ EPDM rubber to form an insulation layer on the outside of each conductor, wherein the extrusion thickness of the ground conductor insulation layer 220 is greater than the extrusion thickness of the main conductor insulation layer 120, so that the insulation outer diameter of the ground conductor 200 is equal to the insulation outer diameter of the power supply main conductor 100; S2, twisting the three power supply main conductors 100 and one ground conductor 200 into a cable, and simultaneously twisting the two control conductors 300... S3. A tensile reinforcing filler strip 400 is placed in the gap of the cable core and placed in the center of the cable core; S4. A high-temperature resistant polyester tape is wrapped around the outside of the cable core after cabling to form a cabling wrapping tape 500; S5. A layer of heat-resistant 125℃ low-smoke halogen-free ethylene-vinyl acetate rubber is extruded and wrapped around the cabling wrapping tape 500 to form a sheath 600; S6. A first protective layer 700 is formed by wrapping the sheath 600 with double-layer fluorophlogopite mica tape, with an overlap rate of 35% to 45% for each layer; S7. A second protective layer 800 is formed by weaving galvanized steel wire on the outer surface of the first protective layer 700, with a weaving density of 40% to 45%.

[0020] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A reinforced rubber-sheathed flexible cable specifically for steel ladle cars, characterized in that: The cable includes at least three main power supply cores (100), at least one grounding core (200), and at least two control cores (300). Each main power supply core (100) includes a main conductor (110) and a main insulation layer (120). Each grounding core (200) includes a ground conductor (210) and a ground insulation layer (220). Each control core (300) includes a control conductor (310) and a control insulation layer (320). The thickness of the ground insulation layer (220) is greater than the thickness of the main insulation layer (120), making the outer diameter of the ground insulation core (200) equal to the outer diameter of the main power supply core (100), thus forming a four-core structure. After cabling, the control core (300) is located in the gap formed by the cabling of the main power supply core (100) and the grounding core (200), with no [unclear text - possibly "inner space"]. Filling material; a tensile reinforcing filler strip (400) is provided at the center of the cable core, the tensile reinforcing filler strip (400) includes an aramid fiber bundle (410) and a filler strip outer skin (420) covering the outer periphery of the aramid fiber bundle (410), the aramid fiber bundle (410) is made of at least three 2500D aramid fibers twisted together; the cable core is wrapped with a cable wrapping tape (500); the cable wrapping tape (500) is covered with a sheath (600); a first protective layer (700) is provided outside the sheath (600), the first protective layer (700) is made of double-layer fluorophlogopite mica tape, the overlap rate of each layer of fluorophlogopite mica tape is 35% to 45%; a second protective layer (800) is provided outside the first protective layer (700), the second protective layer (800) is woven with galvanized steel wire on the outer surface of the first protective layer (700), the weaving density is 40% to 45%.

2. The reinforced rubber-sheathed flexible cable for steel ladle cars according to claim 1, characterized in that: The sheath (600) is made of heat-resistant, low-smoke, halogen-free ethylene-vinyl acetate rubber extrusion molding at 125℃.

3. The reinforced rubber-sheathed flexible cable for steel ladle cars according to claim 1, characterized in that: The main conductor (110), ground conductor (210) and control conductor (310) are all made of 6-type tin-plated copper stranded conductors; the main conductor insulation layer (120), ground conductor insulation layer (220) and control conductor insulation layer (320) are all made of heat-resistant 125℃ ethylene propylene diene monomer rubber extrusion.

4. A method for manufacturing a reinforced rubber-sheathed flexible cable for steel ladle cars according to any one of claims 1 to 3, characterized in that... Includes the following steps: S1. The six types of tin-plated copper stranded conductors are respectively made into main conductor (110), ground conductor (210) and control conductor (310), and a heat-resistant 125℃ binary ethylene propylene rubber is extruded over each conductor to form an insulation layer. The extrusion thickness of the ground core insulation layer (220) is greater than that of the main core insulation layer (120), so that the outer diameter of the ground core (200) insulation is equal to that of the main power supply core (100); S2, at least three main power supply cores (100) and at least one ground core (200) are twisted into a cable, and at the same time at least two control cores (300) are placed in the gaps of the cable core, and a tensile reinforcing filler strip (400) is placed in the center of the cable core; S3, high temperature resistant polyethylene is wrapped around the outside of the cable core after cabling. S4. An ester tape is used to form a cable wrapping tape (500); S5. A heat-resistant 125℃ low-smoke halogen-free ethylene-vinyl acetate rubber is extruded over the cable wrapping tape (500) to form a sheath (600); S6. A double-layer fluorophlogopite tape is used to wrap around the sheath (600) to form a first protective layer (700), with an overlap rate of 35% to 45% for each layer; S7. A galvanized steel wire is used to weave a second protective layer (800) on the outer surface of the first protective layer (700), with a weaving density of 40% to 45%.

5. The manufacturing method according to claim 4, characterized in that: In step S1, the outer diameter of the insulation of the main power supply core (100) is 12.8 mm, and the outer diameter of the insulation of the grounding core (200) is also 12.8 mm by thickening the insulation layer (220) of the grounding core.

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