Simple Evaluation Method of Bipolar Diffusion Charging of Aerosol Particles and Its Application to Smoke Detectors

Abstract

The diffusion charging of polydisperse and monodisperse aerosol particles by bipolar ions was theoretically studied under various conditions. Approximate equations in the simple form were derived to evaluate the changes in the particle charge and the ion number concentration. These approximate equations were applied to analyze the performance of the ionization-type smoke detector. The output response of an ionization-type smoke detector was experimentally tested with monodisperse aerosols, and the experimental response on the particle size and number concentration dependence were found to be explained by the simple approximate equations.