Construction and performance of a modified Wide Range Aerosol Classifier (WRAC)

In order to compare dust samplers of different design, a reference instrument is needed capable of measuring large particles at high wind speeds. Based on a design by Lundgren, the instrument was improved by the following modifications: oil impregnated impaction plates from sintered metal, automatic mass flow control and hyperbolic inlets. The cutoff diameters are 9.2, 20.4, 37.4 and 60.2 micrometers. (ITA)