Low-smoke halogen-free mine-used medium-voltage cable with multi-layer protection structure

Abstract

The utility model discloses a kind of low smoke halogen-free fire-resistant mine-used medium voltage cable with multi-layer protection structure, including several copper conductors, copper conductor outer extrusion and half-conductive shielding layer, half-conductive shielding layer outer extrusion and XLPE insulation, XLPE insulation outer extrusion and outer half-conductive shielding, outer half-conductive shielding outer winding copper band shielding, copper band shielding is equipped with heat insulation layer outside, heat insulation layer outer extrusion and flame-retardant oxygen barrier layer, flame-retardant oxygen barrier layer is equipped with flame-retardant fire barrier layer, flame-retardant fire barrier layer is equipped with flame-retardant layer outside.The utility model is through the gradient design of alkali-free glass cloth tape, ceramic flame-retardant polyolefin and high oxygen index low smoke halogen-free material, realize excellent flame-retardant, fire resistance and environmental protection performance, while using low-temperature extrusion, multi-layer winding and interface compatibility technology, ensure that multi-layer structure synergic flame-retardant, first in medium voltage mine-used cable "heat insulation-oxygen isolation-fire barrier-outer protection" fourfold protection is realized, while meeting low smoke, halogen-free, high flame-retardant, fire-resistant multiple performance requirements.

Description

Technical Field

[0001] This utility model relates to the field of cable technology, and in particular to a low-smoke halogen-free refractory medium-voltage cable for mining with a multi-layer protective structure. Background Technology

[0002] The "Safety Regulations for Metal and Non-metal Mines" (GB 16423-2020) stipulates that dual-circuit cables supplying power underground should be low-smoke, low-halogen, or halogen-free flame-retardant cables. However, current standards for mining cables, especially medium-voltage mining cables, do not explicitly require low-smoke or halogen-free cables. Medium-voltage cross-linked polyethylene (XLPE) insulated power cables operate at higher voltages, and their special electrical performance requirements necessitate that the insulated core consist of a conductive core, conductor shielding, XLPE insulation and insulating shielding, and metallic shielding. Therefore, when manufacturing medium-voltage fire-resistant power cables, simply wrapping fire-resistant mica tape around the conductor is insufficient. Furthermore, there is currently no unified standard for medium-voltage fire-resistant cables in China, and traditional medium-voltage fire-resistant cables are poorly designed, with inadequate flame-retardant and fire-resistant properties, making it difficult to meet the safety requirements of harsh environments such as mines. Utility Model Content

[0003] The purpose of this invention is to provide a low-smoke, halogen-free, fire-resistant medium-voltage cable for mining with a multi-layered protective structure, thereby solving the aforementioned problems.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] This utility model discloses a low-smoke halogen-free fire-resistant medium-voltage mining cable with a multi-layer protective structure, comprising several copper conductors, an inner semi-conductive shielding layer extruded around the copper conductors, XLPE insulation extruded around the inner semi-conductive shielding layer, an outer semi-conductive shielding layer extruded around the XLPE insulation, a copper tape shielding layer wrapped around the outer semi-conductive shielding layer, a heat insulation layer outside the copper tape shielding layer, a flame-retardant oxygen barrier layer extruded around the heat insulation layer, a flame-retardant fire-resistant layer outside the flame-retardant fire-resistant layer, and a flame-retardant layer outside the flame-retardant fire-resistant layer.

[0006] Furthermore, there are three copper conductors, and the included angle between two adjacent copper conductors is 120°.

[0007] Furthermore, the heat insulation layer includes a filler and an alkali-free glass fiber wrapping tape. The filler is filled into the gaps in the cable core. The copper conductor, inner semiconductive shielding layer, XLPE insulation, outer semiconductive shielding, copper tape shielding and filler form the cable core. The alkali-free glass fiber wrapping tape is wrapped around the outer wall of the cable core.

[0008] Furthermore, the filler is alkali-free glass fiber.

[0009] Furthermore, the flame-retardant oxygen barrier layer includes a low-smoke halogen-free oxygen barrier layer and a low-smoke halogen-free wrapping tape. The low-smoke halogen-free oxygen barrier layer is extruded over the alkali-free glass fiber wrapping tape, and the low-smoke halogen-free oxygen barrier layer is wrapped around the low-smoke halogen-free wrapping tape.

[0010] Furthermore, the flame-retardant fireproof layer includes a ceramicized flame-retardant low-smoke halogen-free polyolefin inner sheath extruded onto the surface of the low-smoke halogen-free packaging strip, and a second low-smoke halogen-free strip is wrapped around the ceramicized flame-retardant low-smoke halogen-free polyolefin inner sheath.

[0011] Furthermore, the flame-retardant layer includes a low-smoke halogen-free outer sheath extruded over the low-smoke halogen-free strip.

[0012] Compared with the prior art, the beneficial technical effects of this utility model are as follows:

[0013] This invention achieves excellent flame retardant, fire-resistant, and environmentally friendly performance through a gradient design of alkali-free glass cloth tape, ceramic flame-retardant polyolefin, and high oxygen index, low smoke, and halogen-free materials. At the same time, it adopts low-temperature extrusion, multi-layer wrapping, and interface compatibility technology to ensure the multi-layer structure synergistically retards flames. For the first time, it achieves "heat insulation-oxygen isolation-fire blocking-outer protection" quadruple protection in medium-voltage mining cables, while meeting multiple performance requirements such as low smoke, halogen-free, high flame retardancy, and fire resistance. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings.

[0015] Figure 1 This is a cross-sectional view of the low-smoke, halogen-free, refractory medium-voltage mining cable with a multi-layer protective structure according to this utility model.

[0016] Explanation of reference numerals in the attached diagram: 1. Copper conductor; 2. Inner semiconducting shielding layer; 3. XLPE insulation; 4. Outer semiconducting shield; 5. Copper tape shield; 6. Filler; 7. Alkali-free glass fiber wrapping tape; 8. Low-smoke halogen-free oxygen barrier layer; 9. Low-smoke halogen-free wrapping tape one; 10. Ceramicized flame-retardant low-smoke halogen-free polyolefin inner sheath; 11. Low-smoke halogen-free wrapping tape two; 12. Low-smoke halogen-free outer sheath. Detailed Implementation

[0017] like Figure 1 As shown, a low-smoke halogen-free refractory medium-voltage cable for mining with a multi-layer protective structure includes three copper conductors 1, with an included angle of 120° between two adjacent copper conductors 1. The copper conductors 1 are encased in an inner semi-conductive shielding layer 2, the inner semi-conductive shielding layer 2 is encased in XLPE insulation 3, the XLPE insulation 3 is encased in an outer semi-conductive shielding 4, and the outer semi-conductive shielding 4 is wrapped with a copper tape shielding 5.

[0018] The copper tape shield 5 is provided with a heat insulation layer. The heat insulation layer includes a filler 6 and an alkali-free glass fiber wrapping tape 7. The filler 6 is an alkali-free glass fiber. The filler 6 fills the gaps in the cable core. The copper conductor 1, the inner semiconductive shielding layer 2, the XLPE insulation 3, the outer semiconductive shielding 4, the copper tape shield 5 and the filler 6 form the cable core. The alkali-free glass fiber wrapping tape 7 is wrapped around the outer wall of the cable core.

[0019] The alkali-free glass fiber, used as an insulation layer material, has a melting point exceeding 1600℃ and excellent high-temperature resistance. It can suppress heat conduction and delay insulation aging during cable operation (especially under high load conditions). Simultaneously, it can prevent flame spread. The alkali-free glass fiber wrapping tape 7 is wrapped around the cable core, with a thickness of 0.2mm, 2-4 layers, and an overlap rate of over 20%. The alkali-free glass fiber filler and alkali-free glass cloth tape are mainly made of alkali-free glass fiber, with a thermal conductivity of 0.035W / m·K, good heat resistance, and high mechanical strength. It effectively prevents high temperatures from being transferred to the insulation layer, improving the cable's safety in a fire.

[0020] The heat insulation layer is extruded with a flame-retardant oxygen barrier layer, which includes a low-smoke halogen-free oxygen barrier layer 8 and a low-smoke halogen-free wrapping tape 9. The low-smoke halogen-free oxygen barrier layer 8 is extruded over the alkali-free glass fiber wrapping tape 7, and the low-smoke halogen-free oxygen barrier layer 8 is wrapped around the low-smoke halogen-free wrapping tape 9.

[0021] Specifically, the flame-retardant oxygen barrier layer consists of a highly flame-retardant low-smoke halogen-free oxygen barrier layer 8 and a low-smoke halogen-free wrapping tape 9. The low-smoke halogen-free oxygen barrier layer 8 is extruded onto the surface of alkali-free glass cloth tape, with an oxygen index ≥42. When the cable is exposed to an open flame, the low-smoke halogen-free oxygen barrier layer 8 decomposes to generate water vapor, absorbing heat and lowering the temperature. It then rapidly forms a non-melting, non-combustible hard shell-like oxygen barrier layer, blocking oxygen from contacting the combustible XLPE insulation 3 inside the cable, achieving a self-extinguishing effect. The low-smoke halogen-free wrapping tape 9 is wrapped around the surface of the low-smoke halogen-free oxygen barrier layer 8, with a thickness of 0.2mm, 2-3 layers, and an overlap rate of over 20%. The low-smoke halogen-free wrapping tape 9 contains flame retardants such as aluminum hydroxide and magnesium hydroxide. When exposed to fire, it decomposes, absorbs heat, and releases water vapor, lowering the combustion temperature. Simultaneously, it forms a non-combustible carbonized layer, isolating oxygen from contacting the combustible substrate, further enhancing the flame-retardant and oxygen-barrier effect.

[0022] The flame-retardant oxygen barrier layer is provided with a flame-retardant fire-blocking layer. The flame-retardant fire-blocking layer includes a ceramicized flame-retardant low-smoke halogen-free polyolefin inner sheath 10 extruded onto the surface of the low-smoke halogen-free packaging tape 9, and a low-smoke halogen-free tape 11 is wrapped around the ceramicized flame-retardant low-smoke halogen-free polyolefin inner sheath 10.

[0023] Specifically, the flame-retardant fire-barrier layer consists of a ceramicized flame-retardant low-smoke halogen-free polyolefin inner sheath 10 and a low-smoke halogen-free strip 11. The ceramicized flame-retardant low-smoke halogen-free polyolefin inner sheath 10 is extruded onto the surface of the flame-retardant oxygen barrier layer. This material is produced through polymer processing technology, possessing both low-smoke halogen-free flame-retardant properties and ceramicization functionality. At high temperatures, the flame-retardant components of this material form a non-melting and non-combustible alumina hard shell, preventing the spread of flames and oxygen, while simultaneously releasing a large amount of moisture to absorb heat and cool the cable. The low-smoke halogen-free strip 11 wrapped around the ceramicized flame-retardant low-smoke halogen-free polyolefin inner sheath 10 has a thickness of 0.2 mm, with 2-3 layers and an overlap rate of over 20%. The ceramicized flame-retardant low-smoke halogen-free polyolefin inner sheath 10 and the low-smoke halogen-free strip 11 together constitute the flame-retardant fire-barrier layer, preventing the flame from spreading inward and providing impact protection.

[0024] The flame-retardant fire-resistant layer is surrounded by a flame-retardant layer, which includes a low-smoke halogen-free outer sheath 12 extruded over the low-smoke halogen-free strip 11. The low-smoke halogen-free outer sheath 12 is made of a highly flame-retardant, low-smoke halogen-free material extruded over the surface of the low-smoke halogen-free strip 11, with an oxygen index ≥40%. It is not easily ignited when exposed to an open flame, and its flame propagation speed is extremely low (more than 30% slower than ordinary materials), effectively suppressing the spread of fire.

[0025] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A low-smoke, halogen-free, fire-resistant medium-voltage mining cable with a multi-layered protective structure, characterized in that: The cable includes several copper conductors (1), with an inner semiconductive shielding layer (2) extruded around the copper conductors (1), XLPE insulation (3) extruded around the inner semiconductive shielding layer (2), an outer semiconductive shielding layer (4) extruded around the XLPE insulation layer (3), a copper tape shielding layer (5) wrapped around the outer semiconductive shielding layer (4), a heat insulation layer outside the copper tape shielding layer (5), a flame-retardant oxygen barrier layer extruded around the heat insulation layer, a flame-retardant fireproof layer outside the flame-retardant oxygen barrier layer, and a flame-retardant layer outside the flame-retardant fireproof layer; the heat insulation layer includes a filler (6) and an alkali-free glass fiber wrapping tape (7), the filler (6) filling the gaps in the cable core, and the copper conductors (1), inner semiconductive shielding layer (2), and XLPE insulation layer (7) wrapping tape (8) wrapping tape (8). Insulation (3), outer semiconductive shield (4), copper tape shield (5) and filler (6) form the cable core, and the alkali-free glass fiber wrapping tape (7) is wrapped around the outer wall of the cable core; the flame-retardant oxygen barrier layer includes a low-smoke halogen-free oxygen barrier layer (8) and a low-smoke halogen-free wrapping tape one (9), the low-smoke halogen-free oxygen barrier layer (8) is extruded over the alkali-free glass fiber wrapping tape (7), and the low-smoke halogen-free oxygen barrier layer (8) is wrapped around the low-smoke halogen-free wrapping tape one (9); the flame-retardant fireproof layer includes a ceramicized flame-retardant low-smoke halogen-free polyolefin inner sheath (10) extruded over the surface of the low-smoke halogen-free wrapping tape one (9), and the ceramicized flame-retardant low-smoke halogen-free polyolefin inner sheath (10) is wrapped around the low-smoke halogen-free tape two (11).

2. The low-smoke halogen-free refractory medium-voltage mining cable with a multi-layer protective structure according to claim 1, characterized in that: The copper conductor (1) is provided in three parts, and the included angle between two adjacent copper conductors (1) is 120°.

3. The low-smoke halogen-free refractory medium-voltage mining cable with a multi-layer protective structure according to claim 1, characterized in that: The filler (6) is alkali-free glass fiber.

4. The low-smoke halogen-free refractory medium-voltage mining cable with a multi-layer protective structure according to claim 1, characterized in that: The flame retardant layer includes a low-smoke halogen-free outer sheath (12) extruded outside the low-smoke halogen-free strip (11).

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