Direct ignition tests of brush discharges for explosive methane-air and propane-air gas mixtures

The applied experimental set-up enabling measurements of current waveforms and charge transferred during direct ignition tests with brush discharges, was presented in the paper. Tests were conducted with ignition probe designed according to the IEC 60079-32-2 Standard for methane-air gas and propane-air gas mixtures. In the experiment 100 trials were conducted using sample consisted of fluorinated polyethylene. The sample was rubbed with sheep felt cloth. Charge transfer measured rates ranged from 50 nC to 260 nC and the current peak magnitude ranged from 0.5 A to 3.5 A. Magnitude of the current peak as a function of the transferred charge, recorded in the experiment, was presented in the paper. Two regions can be distinguished on the Q = f(dQ/dt) characteristic. There is a region where discharges do not cause ignition and the other one, where the results indicate ignition of gas mixture.