Calculation of MIE and electromagnetic energy in an antistatic properties testing system used in mines and its application

The MIE (Minimum Ignition Energy) characterizes the danger of a kind of combustible gas and its ignition behavior, and the antistatic test for the non-metallic materials is of great value to mining industry. This paper describes an antistatic level testing system for the non-metallic materials used in mines, and the methods to calculate the MIE of the ignition system, electromagnetic energy and scale the antistatic grade are also presented in details. According to the structure of the antistatic level testing system, the model to calculate the electromagnetic energy of the ignition system is set up firstly, then the MIE and electromagnetic energy before and after ignition are computed respectively. The ignition energy coupling coefficient is defined to indicate the ratio between the energy used for ignition and the total electromagnetic energy, based on which the quantity of triboelectric charge produced by the testing material can be obtained. The numerical relation between the ignition energy coupling coefficient and electrode gap is investigated, for the system described in the paper the threshold of ignition energy coupling coefficient increases from 0.42 to 0.77 when the gap distance increases from 1 mm to 5 mm. The system designed in the paper can be used to test the possibility of ignition and explosion for non-metallic devices used in mine, and the safety limit space for different material can be determined. In addition, it also offers reference for the scaling of triboelectric charge.