Comparison and analysis of different measuring methods to determination ofminimum ignition energy of combustible dusts

The minimum ignition energy (MIE) is a measure of ignition sensitivity for explosive mixtures. It is used among other safety characteristics to assess the hazard potential of dust and to select protective measures. In this pa per the measurement methods of minimum ignition energy of dust/ air-mixture s and three different test apparatus (Hartmann-pipe, 20 l-sphere, vertical duct with vibration sieve feeding) are analysed and compared. Analysis and comparison bases on a space and time dependent investigation of the dust co ncentration, the state of turbulence and dust dispersion inside the test vo lumina of the apparatus. The state of turbulence is measured by Laser-Doppl er-anemometry; for the determination of the dust dispersion state and the d ust concentration resp., individual methods are developed. The mentioned MI E apparatus are characterized according to their capability and the thus ga ined measuring size MIE is set in relation to other (nonelectrostatic) igni tion sources which occur in the food stuff industry.