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Dependence of particulate sampling effeciency on inlet orientation and flow velocities.

Authors
Tufto-PA; Willeke-K
Source
Am Ind Hyg Assoc J 1982 Jun; 43(6):436-443
NIOSHTIC No.
00126481
Abstract
An airborne particulate sampler inlet was studied for sampling efficiency through the use of a wind tunnel apparatus. Liquid particles entering the inlet were registered on an optical particle counter. The magnitude of particle deposition in the inlet tube was obtained with a uranine labelled oleic-acid aerosol and washoff that related the fluorescence to the number of deposited particles. Liquid particles of oleic acid ranged in diameter from 5 to 40 micrometers. Wind velocity varied from 250 to 1000 centimeters per second (cm/s) and the inlet velocity varied from 125 to 1000cm/s. The inlet was tested isoaxial to the wind at angles 0 to 30 degrees, with the optical counter inside the wind tunnel. At angles 60 to 90 degrees the counter was inside the tunnel. Wind tunnel turbulence of a few percent had no effect on sampling efficiency. Particle aspiration to the inlet face affected small particle isoaxial sampling, while gravitational sedimentation in the horizontal inlet tube was the removal mechanism for large particles. Downward air sampling resulted in higher sampling efficiency than upward sampling for particle size above 10 micrometers. The effect of gravity on sampling efficiency was most pronounced between upward angle 15 degrees and downward 15 degrees. Gravity became less important with increase in angle. As orientation of the inlet angled away from the wind vector, lack of aspiration increased both particle loss and particle impaction just inside the inlet face.
Keywords
NIOSH-Publication; NIOSH-Grant; Analytical-methods; Laboratory-techniques; Air-sampling-equipment; Air-monitoring; Air-quality-measurement; Equipment-design; Analytical-instruments; Sampling-equipment
Contact
Environmental Health University of Cincinnati 3223 Eden Avenue Cincinnati, Ohio 45267
CODEN
AIHAAP
Publication Date
19820601
Document Type
Journal Article
Funding Amount
101468.00
Funding Type
Grant
Fiscal Year
1982
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-00774
Issue of Publication
6
ISSN
0002-8894
Source Name
American Industrial Hygiene Association Journal
State
OH
Performing Organization
University of Cincinnati, Cincinnati, Ohio
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