Aerosol Charge Neutralization by a Corona Ionizer

A new aerosol neutralizer, which makes use of a corona ionizer to produce bipolar ions, has been designed and evaluated. The corona neutralizer consists of three components: a dual-needle ionizer for the generation of bipolar ions, an opposing-jet mixer for the uniform mixing of ions and particles, and a charging chamber for particle charge neutralization by ions. The bipolar ionizer consists of two unipolar ionizers for producing positive and negative ions, respectively. They are mixed to obtain the appropriate mixture of bipolar ions. Aerosol particals are then mixed with the bipolar ions in the mixer and are electrically discharged by collision with the bipolar ions in the charging chamber. The charge distribution of aerosol particles exiting the new corona neutralizer is found to depend on the ratio of electric current of positive ions and negative ions I − / I − and to attain the Boltzmann charge distribution at I + / I − = 1.0. The neutralizer has been shown to effectively reduce the particle charges from either the high unipolarly charged or bipolarly charged states to the Boltzmann charge distribution