IN SITU AERODYNAMIC SIZE CLASSIFICATION OF AEROSOLS IN THE SIZE RANGE BETWEEN 0.1 AND 100 μm FOR DUSTINESS TESTS AND POWDER CHARACTERIZATION

Airborne particles can be released by mechanical processes such as resuspension, powder handling, break-up of solids due to mechanical energy input, i.e. crushing, comminution or accidental mechanical impact. In this study, we describe a new device that collects and classifies the dust generated under lab-scale simulation of these release processes. The release process takes place within a vertical elutriator where the airborne particles are separated from the non-airborne material. The airborne fraction is subsequently classified in situ in the size range between 0.1 and 100 μm by a combination of a centrifugal classifier and a conventional cascade impactor. The system was designed to overcome possible sampling errors due to spatial dust inhomogeneities caused by the release process and to minimize wall losses during the classification process. In this paper we describe the classifier, discuss procedures for data inversion, and present calibration and performance experiments.