Selection and maintenance of explosion-proof electrical appliances in Dalian coal mine underground: key measures to cope with humid and dusty environments

Selection and maintenance of explosion-proof electrical appliances in Dalian coal mine underground: key measures to cope with humid and dusty environments

The underground environment of coal mines is special, with high humidity (relative humidity often above 90%), high dust (coal dust and rock dust diffuse), and the presence of combustible gases such as gas. This places extremely high demands on the selection and maintenance of explosion-proof electrical appliances, and requires targeted key measures to avoid safety risks.

The selection of explosion-proof electrical appliances in Dalian should prioritize the parameter of "environmental adaptability". In terms of explosion-proof level, explosion-proof (Ex d) electrical appliances that comply with GB 3836.2 standard must be selected, and the explosion-proof mark must include "Class I" (coal mine specific), such as Ex d I BT4, to ensure resistance to gas explosion risks; The protection level should reach IP65 or above, which can completely prevent dust and spray water, avoiding dust intrusion into the equipment and moisture corrosion of the circuit. In terms of material selection, the shell is preferably made of thickened cast steel or stainless steel, which is more resistant to coal dust wear and moisture corrosion than ordinary cast aluminum; Internal wiring terminals should be made of nickel plated copper to prevent poor contact caused by oxidation in humid environments.

 

The maintenance of explosion-proof electrical appliances in Dalian should revolve around the dual core of "moisture prevention and dust removal". During daily inspections, it is necessary to use compressed air (pressure ≤ 0.3MPa) every week to blow away dust from the electrical casing and heat dissipation holes, in order to prevent dust accumulation from affecting heat dissipation or invading the interior; Disassemble and inspect sealing components every month, such as explosion-proof sealing rings and cable gland gaskets. If aging or deformation occurs, replace them immediately. At the same time, apply special anti rust grease to the explosion-proof surface to prevent corrosion and ensure explosion-proof clearance. During the rainy season, it is necessary to increase the frequency of insulation testing and measure the insulation resistance of electrical appliances every two weeks with a shaking table to ensure that it is ≥ 1M Ω, in order to prevent moisture from causing electrical leakage. In addition, it is necessary to avoid frequent starting and stopping of electrical appliances, reduce condensation caused by sudden temperature changes, and further reduce the risk of malfunctions caused by humid environments.