Electric charging characteristic of a mixer-type powder disperser

The charging characteristic of a mixer-type powder disperser has been studied experimentally. A dry powder was dispersed and electrically charged simultaneously inside the disperser. The charging performance was evaluated in terms of the mean value of specific charge measured by a Faraday cage. The effect of the disperser's configuration and operating conditions on the generated electrical charge were investigated. The measured particle charge was found to decrease with operating time and reached a constant value after 15 min. One of the reasons for this time-dependent characteristic is the formation of a powder layer on the wall surface. As for the charging mechanism, it can be concluded that particles contacting with the inside wall of the disperser are responsible for most of the observed charge. The charging effect, however, deteriorated at the double-wall section of the disperser when the effective height was over 100 mm.