Experimental design of high volume electrostatic charger

A corona charger was developed for charging aerosols having flow rates of 0.6-6.0 m(3)/s. To prevent wall loss transpiration flow from 0.6-4.8 m(3)/s was introduced at 90 degrees from the principal direction of flow. The redesigned charging section could produce ion currents as high as 10(-4) A for applied corona voltages below 10 kV. Calibration experiments with glass aerosols showed that particle penetration through the charging section could be substantially increased by the use of transpiration air, that the transpiration air did not alter the shape of the particle size distribution, and that for particles less than 0.5 mu m, diffusion charging was the dominant mechanism. (C) 1997 American Association for Aerosol Research.