Dynamic evaluation of aerosol sampling inlets.
Environ Sci Technol 1982 Sep; 16(9):607-609
A technique for dynamically determining the efficiency of aerosol sampling inlets was described. The inlet under study was integrated into an optical single particle counter that had been modified to accept flow rates up to 75 liters per minute. The inlet and particle counter were used inside a specially designed wind tunnel. Test aerosols were injected into the mixing chamber of the wind tunnel by means of an aerosol generator whose design was based on the vibrating orifice principle. The inlet under study took samples from the aerosol flow in the test section of the wind tunnel. The aerosol flow rate was calibrated and measured during testing by taking the pressure difference between the static pressure tap and the upstream static pressure. Downstream from the counter the aerosols were removed by in line filters. Data obtained for a thin walled sampling tube operated at 30 degrees downward from the flow direction that utilized 5 to 40 micron diameter oleic-acid particles as the test aerosol, were presented. Because each particle was counted individually the required sampling times were short and the scatter in the data was low. The authors suggest that the new technique should enable sufficient data with a low degree of scatter be taken so that analytical models for predicting sampling efficiency of various inlets can be developed.
NIOSH-Publication; NIOSH-Grant; Control-technology; Industrial-hygiene; Laboratory-testing; Aerosol-sampling; Equipment-design; Equipment-reliability
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Environmental Science and Technology
University of Cincinnati, Cincinnati, Ohio