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2074690 
Technical Report 
Final Report. Design And Calibration Of A Low Flow Parallel Stage Impactor 
Esmen, NA; Weyel, DA; Tuchman, DP 
1983 
NIOSH/00148514 
U 
1R01-OH-01228-01 
01228-01 
The design and calibration of a miniature parallel stage impactor was described. The impactor was constructed primarily of aluminum, out of a 3 by 1.5 by 12 inch rectangular block, and contained 6 sintered brass impactor stages. One stage was intended for collecting total air particulates. The other stages had cut off diameters of 0.47, 0.75, 1.90, 3.12, and 7.43 microns. Critical orifice needle valves were used. The valve assemblies were constructed of stainless steel. The instrument was calibrated with a uranine test aerosol at an air flow rate of 700 cubic centimeters per minute. The observed 50 percent cut off aerodynamic equivalent diameters for the first five stages were 0.47, 0.75, 1.90, 3.12, and 7.43 microns. The corresponding theoretical values were 0.38, 0.72, 1.80, 3.10, and 7.40 microns, respectively. The authors conclude that the parallel stage impactor is a reliable instrument. Parallel stage impactors can be miniaturized successfully and do not present any new disadvantages other than those that are inherent to any impactor device.