Determining minimum ignition energy in the MIKE 3 apparatus

Determining minimum ignition energy of a product in powder form is performed in the MIKE 3 apparatus as defined in DIN EN ISO 80079-20-2 (formerly DIN EN 13821).

The minimum ignition energy is the lowest electrical energy stored in a capacitor, as determined under prescribed test conditions, which, when discharged, is just sufficient to ignite the most ignitable mixture of a given dust. The minimum ignition energy decreases with decreasing particle size and with increasing temperature.

The apparatus consists of a modified Hartmann tube made of glass. In the middle of the tube are two holes to insert the electrodes, which can induce energy between 1 mJ and 1,000 mJ. At the bottom of the apparatus is a dust dispersing system which whirls up the dust in the apparatus with compressed air of 7 barg and produces a dust-air mixture of varying concentration. The mixture is ignited at the electrodes. The tests are carried out with various ignition delay times and ignition energies. The test results are evaluated visually. The test of the minimum ignition energy can be performed both at room temperature and at elevated temperature. The test can be performed both with and without an inductive resistor in the ignition circuit.