Wire annealed bare copper wire of mine communication cable structure, copper wire diameter is 0.30, 0.42, 0.52, 0.60, 0.70, 0.80, 0.90(mm).
Insulating materials, high-density polyethylene or polypropylene, color of insulating wire as per full chromatographic standard.
Two different colored insulated wires were twisted into pairs at different pitches and a specified chromatographic combination was used to identify the wire pairs.
The cable core structure of communication cables takes 1 pair as the basic unit, more than 25 pairs of cables are combined in units, and each unit is wound with the specified chromatographic unit tie tape, so as to identify different units.
Cable with 100 or more cable pairs plus 1% reserve cable pairs, but not more than 6 pairs at most.
The gap in the cable core is filled with petroleum paste.The core wrap is wrapped with polyester film wrap.Shielding copper wire or rolled (or unrolled) metal strip, which is longitudinally enclosed in addition to the cable core cladding.Jacket blue low density polyethylene.Double jacketed communication cables are also available.
Identification and Length marking of mine communication cables Permanent identification marks shall be placed on the outer surface of the cables at intervals of not more than 1m. The marks shall include wire diameter, number of wire pairs, cable type, manufacturer's code name and year of manufacture. The length marks shall be marked on the outer surface at intervals of not more than 1m but shall be staggered with the above marks.
Mine communication cable adopts full chromatography insulation, alumino-plastic integrated sheath (that is, the cable's longitudinal-coated shielded aluminum belt and sheath are bonded together to form a sealed sheath), with superior electrical performance and convenient construction.The main causes of fire are overload, short circuit, excessive contact resistance and external heat source.
In short circuit, local overheating and other fault state and external thermal action, insulation material insulation resistance decline, loss of insulation ability, or even combustion, and then cause fire.
The main characteristic of mine cables in the fire is that the fire temperature is generally 800℃ ~ 1000℃, in the case of fire, the conductor and cable will soon lose insulation ability, and then cause short circuit and other secondary electrical accidents, causing greater losses;
The conductor and cable have great overload capacity under the specified allowable carrying capacity;
In a short circuit, the conductor and cable will instantly cause the insulation to melt, burn, and ignite the surrounding combustibles.
Analysis of fire performance of mine cable Analysis of fire retardant mechanism Analysis of fire retardant mechanism Under the thermal action of combustion reaction, the flame retardant located in the condensed phase decomposes and absorbs heat, which slows down the rise of temperature in the condensed phase and slows down the thermal decomposition rate of materials.
After the flame retardant is decomposed by heat, the free radical blocker of chain reaction is released, which interrupts the branches of flame and chain reaction and slows down the reaction rate of gas.
The formation of coking layer or foam layer strengthened the effect of these hard shells on heat transfer.
Under the action of heat, the flame retardant exhibits endothermic phase transition, which physically prevents the temperature in the condensed phase from rising.
Fireproof mechanism Some additive is added to the insulation and sheath material of mine cable to reduce the heat generated by polymer, prevent polymer decomposition or promote the carbonization of insulation and sheath material to form protective layer;
Inorganic insulation materials such as mica glass ribbon are added to the core of the line. After the insulation and jacket layer are corroded by fire, * the mica fireproof tape wrapped on the conductor continues to electrize, so as to maintain normal operation for a certain time in case of fire.