Evaluation of a High Efficiency Unipolar Charger for Aerosol Particles

Abstract

A unipolar charger of submicron aerosol particles has been evaluated. Firstly, a high-voltage field ionization method is utilized to produce sufficient free charges, and an external migrating electric field is then utilized to migrate the free charges into a particle-charging region in order to realize the high-efficient charging of aerosol particles. The charger comprises an impact type particle cutter, a particle-charging chamber and a high-voltage power supply. The charger has a compact structure, which is convenient to maintain and can realize the high-efficient charging of aerosol particles below 1μm. The charger can be used in the pre-stage charging of particles on the basis of an electric migration characteristic monitoring device. For large particles (250–600 nm) the extrinsic charging efficiency of the charger with migration electric field are approximately 1.2 times higher than those of the charger with migration electric field. The charger with migration electric field has advantages of extrinsic charging efficiency, which benefit its application in the aerosol particle charging.