1. Product Purpose and Features
Mine leaky coaxial cables are mainly applied to underground wireless communication systems, precise positioning systems for personnel and equipment, locomotive transportation monitoring systems, emergency communication and rescue. It is a special type of cable integrating the functions of "transmission line" and "antenna", and meets the extreme safety requirements for underground coal mines.
2. Product Standards
GB/T2951-2008
3. Product Models and Names
Serial No. | Name | Model | Specification |
1 | Mine Leaky Coaxial Cable | MSLYFVZ | 50-9 |
2 | Mine Leaky Coaxial Cable | MSLYFVZ | 75-9 |
3 | Mine Leaky Coaxial Cable | MSLYFYVZ | 50-9 |
4 | Mine Leaky Coaxial Cable | MSLYFYVZ | 75-9 |
Table1
4.Product Specifications
Model | Inner Conductor | Insulation | Outer Conductor | Sheath | ||||
Material | Diameter mm | Material | Diameter mm | Material | Diameter mm | Material | Diameter mm | |
MSLYFYVZ-50-9 |
Copper or Copper-clad Aluminum | 3.5±0.05 |
Physically Foamed Polyethylene Insulation |
8.8 ±0.2 |
Braided or stranded copper wire(Braiding density 40~ 55%) |
≤9.8 | Low DensityPolyethylene+Flame RetardantPVC | ≤13.7 |
MSLYFYVZ-75-9 | 2.0±0.03 | ≤13.7 | ||||||
MSLYFVZ-50-9 | 3.5±0.05 | Flame Retardant PVC | ≤12.6 | |||||
MSLYFVZ-75-9 | 2.0±0.03 | ≤12.6 | ||||||
Table2
5. Technical Requirements
5.1 Environmental and Mechanical Properties
5.1.1 Low Temperature Test
Test temperature: -40±3°C, test bending radius: 250mm.
Table3 Mechanical Properties of Insulation and Sheath
No. | Test Item | Technical Requirements | |
PE Inner Sheath | PVC Sheath | ||
1 | Mechanical Properties Before Aging | ||
1.1 | Tensile Strength (N/mm2) | ≥10 | ≥12.5 |
1.2 | Elongation at Break (%) | ≥350 | ≥150 |
2 | Thermal Aging Test | ||
2.1 | Test Temperature (°C) | 90±2 | 100±2 |
2.2 | Test Duration (h) | 4×24 | 7×24 |
2.3 | Tensile Strength (N/mm2) | — | ≥12.5 |
2.4 | Elongation at Break (%) | — | ≥150 |
2.5 | Variation Rate of Elongation at Break (%) | ≥-35 | Not exceeding ±25 |
5.1.2 Flame Retardant Test
The flame retardant performance of the cable shall comply with the test requirements specified in Clause 5.4.2 of GB43069-2023.
5.1.3 The lead and arsenic content of cable materials shall meet the requirements of Clause 5.5.1 of GB43069-2023.
5.2 Electrical Properties
5.2.1 Conductor Continuity Test
No short circuit or open circuit shall occur between inner and outer conductors.
5.2.2 DC Resistance of Inner Conductor
The DC resistance of inner conductor shall conform to the requirements in Table 4.
Table4 DC Resistance of Inner Conductor at 20℃
Item | Material | MSLYF(Y)VZ-50-9 | MSLYF(Y)VZ-75-9 |
DC Resistance of Inner Conductor 20℃, max Ω/km |
Copper Wire |
1.8 |
6.0 |
5.2.3 Insulation Resistance
The insulation resistance of finished cable at 20℃ shall be no less than 1000MΩ·km.
5.2.4 Dielectric Strength of Insulation
The finished cable shall withstand power frequency voltage withstand test of 1.5kV (r.m.s.) for 1min without breakdown.
5.2.5 Characteristic Impedance
Characteristic impedance is shown in Table 5.
Table5 Characteristic Impedance
No. | Model & Specification | Characteristic Impedance(Ω) |
1 | MSLYF(Y)VZ-50-9 | 50±3 |
2 | MSLYF(Y)VZ-75-9 | 75±3 |
5.2.6衰减常数
衰减常数应符合表6要求。
5.2.7耦合损耗
耦合损耗应符合表6要求。
表6衰减常数和耦合损耗
序号 | 型号规格 | 衰减常数（dB/km） | 耦合损耗（dB） | ||||
60MHz | 150MHz | 450MHz | 60MHz | 150MHz | 450MHz | ||
1 | MSLYF（Y）VZ-50-9 | ≤40 | ≤60 | ≤100 | 85±10 | 75±10 | 75±10 |
2 | MSLYF（Y）VZ-75-9 | ≤40 | ≤55 | ≤100 | 80±10 | 80±10 | 75±10 |
5.2.8 Voltage Standing Wave Ratio
The voltage standing wave ratio of the cable within the frequency band of 60MHz～450MHz shall not be greater than 1.3.4.4
5.3 Delivery Length
The standard delivery length of cables shall be an integer multiple of 100m or 200m. Subject to the agreement between the supplier and purchaser, any length is acceptable for delivery. The tolerance of length marking shall not exceed ±1.0%.
6 Test Methods and Acceptance Rules
6.1 Factory Delivery Requirements
All cables shall be inspected by the manufacturer’s quality inspection department and can only be delivered after passing inspection. Each delivered cable shall be accompanied by a quality inspection certificate.
6.2 Product Inspection
Cable inspections are classified into Type Test (T), Routine Test (R) and Sampling Test (S). Inspection items, test types and test methods shall be implemented in accordance with Table 7.
Table 7 Test Methods and Inspection Rules
No. | Item Name | Technical Requirement | Clause No. | Test Type | Test Method (Standard No.) |
1 | Structural Dimensions | This Standard | 4.1.1 | T、S | GB/T15285 |
2 | Mechanical Properties of Insulation and Sheath | This Standard | T | GB/T2951 | |
3 | Electrical Properties | This Standard | |||
3.1 | DC Resistance of Inner Conductor | This Standard | 4.3.2 | T、R | GB/T17737.1 |
3.2 | Insulation Resistance | This Standard | 4.3.3 | T、R | GB/T15285 |
3.3 | Dielectric Strength of Insulation | This Standard | 4.3.4 | T、R | GB/T15285 |
3.4 | Characteristic Impedance | This Standard | 4.3.5 | T、S | GB/T17737.1 |
3.5 | Attenuation Constant | This Standard | 4.3.6 | T、S | GB/T15285 |
3.6 | Coupling Loss | This Standard | 4.3.7 | T、S | GB/T15285 |
3.7 | Voltage Standing Wave Ratio | This Standard | 4.3.8 | T、S | GB/T15285 |
4 | Low Temperature Performance | This Standard | 4.2.1 | T | GB/T17737.1 |
5 | Flame Retardant Performance | ||||
Single Vertical Flame Test | This Standard | 4.2.2 | T,S | GB43069-2023 | |
6 | Lead and Arsenic Content of Cable Materials | This Standard | 4.2.3 | T | GB43069-2023 |
7 | Appearance and Marking | This Standard | 6 | T、S | Visual Inspection |
6 Packaging, Marking, Transportation and Storage
6.1 Packaging
Cable delivery drums shall comply with the provisions of JB/T8137. Cables shall be delivered in coils or on drums, and both ends of each cable shall be sealed. Cables delivered in coils shall be neatly bundled and packed; for cables delivered on drums, the distance between the outermost layer of cable and the outer edge of the delivery drum shall not be less than 20mm.
6.2 Packaging Markings
Each coil or drum of cable shall be attached with a label indicating the following contents:
1) Name of manufacturer;
2) Product model and specification;
3) Length (m);
4) Manufacturing date or production batch number;
5) Number of this standard;
6) Safety mark identification.
6.3 Transportation and Storage
Precautions shall be taken during cable transportation and storage: prevent water and moisture from invading the cable; avoid high temperature and open flames; avoid severe bending and extrusion deformation; prevent any mechanical damage.
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