METHODS FOR ELECTROSTATICALLY CHARGING UP SOLID OR LIQUID PARTICLES SUSPENDED IN A GAS STREAM BY MEANS OF IONS

摘要

A method for electrostatically charging up particles suspended in a gas stream by means of ions originating from a separate unipolar ion source, wherein the ions are injected into the gas/particle stream by means of an alternating field and are deposited on the particles. The frequency of the alternating field is chosen so high at the specified maximum field strength that the drive velocity of the ions during a half-cycle is insufficient to carry the ions to the counter-electrode. As a result, undesirable wall recombination of the ions is avoided.