Abstract
The corona discharge represents the main physical mechanism involved in the charging of granular materials in high-tension separators. This is why an attempt has been made to formulate several criteria for choosing the most adequate electrode. A crude evaluation of the required corona current for an efficient charging has been considered as a necessary starting point for a wellgrounded decision on the type of electrode to be employed with a certain application. The specific features of several models of corona electrodes are briefly discussed, in order to justify the need for a new design. The original corona electrode proposed by the authors is characterized by lower corona on-set voltage, better stability of the corona discharge during long-time operation, and shorter maintenance time, as compared to "classical" solutions. Systematic experiments made on a laboratory model of this electrode enable several design considerations that could be easily extended to other similar devices. Two industrial high-tension separators are already provided with the new type of electrode.