The bipolar charge aerosol classifier

The purpose of the paper is to briefly review some of the methods used to obtain aerosol bipolar charge distribution and to describe a novel instrument developed at Brunel University. The bipolar charge aerosol classifier (BCAC) is an improved version of the authors´ previously published bipolar charge measurement system (2001), eliminating some of his technical limitations. The BCAC is dedicated for characterizing aerosols exiting in the form of short duration, high velocity plumes with a relatively wide angle of particle dispersion delivered from the dispensing device. The instrument incorporates a front-end cylindrical arrangement consisting of ten well-insulated sections. Each of these sections is comprised of a cylindrical capacitor with a coaxial wire electrode maintained at a DC potential. Experimental tests were carried out with unipolarly and bipolarly charged aerosols of narrow size distribution. The preliminary results show that proposed technique can be successfully utilized for obtaining not only bipolar charge aerosol fractions but also indicate electrical mobility distribution.