Size Measurement of Fine Powders Using the Differential Mobility Analyzer--Application of Boiling Method for Aerosol Generation

A method for aerosol generation, termed the "boiling method," was previously developed to effectively disperse in air a powder consisting of coagulated submicron particles into their primary particles. Here, in order to apply the boiling method to the particle size measurement of a fine powder, the method is combined with a particle size measurement system comprising a differential mobility analyzer (DMA) and a condensation nucleus counter (CNC). To avoid the presence of residue particles after evaporation, Fluorinert (perfiuorocarbon) has been chosen as the boiling liquid medium. The particle size distributions measured for several kinds of powders are in good agreement with the results obtained by electron microscope and centrifugal sedimentation method. The method is found to be useful for the particle sizing of fine powders in air. Moreover, the method can also be successfully used as a continuous generator of mono disperse aerosol particles having a high concentration.