Characterization of high concentration dust generator

This paper describes the development of fluidized bed type high concentration dust generator that keeps for long period dust concentration range of about 10 mg/m3 for the study of working place monitoring system and evaluation of respirator. The generator is keeping constant powder in fluidized bed for keeping the dust concentration. It is necessary to keep constant feeding rate of powder in order to keep the quantity of dust in the fluidized bed. Our generator enables to obtain constant feeding rate by a screw feeder and by using mixed powder with fluidising particles (glass beads) before feeding. The generator produces high concentration dust of 11.3 mg/m3 ± 1.0 mg/m3 for about 5 hours and keeps the dust size 4.2-4.6 μm in mass median aerodynamic diameter with reasonable reproducibility. (author)