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Title: High efficiency virtual impactor

Abstract

Environmental monitoring of atmospheric air is facilitated by a single stage virtual impactor (11) for separating an inlet flow (Q.sub.O) having particulate contaminants into a coarse particle flow (Q.sub.1) and a fine particle flow (Q.sub.2) to enable collection of such particles on different filters (19a, 19b) for separate analysis. An inlet particle acceleration nozzle (28) and coarse particle collection probe member (37) having a virtual impaction opening (41) are aligned along a single axis (13) and spaced apart to define a flow separation region (14) at which the fine particle flow (Q.sub.2) is drawn radially outward into a chamber (21) while the coarse particle flow (Q.sub.1) enters the virtual impaction opening (41). Symmetrical outlet means (47) for the chamber (21) provide flow symmetry at the separation region (14) to assure precise separation of particles about a cutpoint size and to minimize losses by wall impaction and gravitational settling. Impulse defocusing means (42) in the probe member (37) provides uniform coarse particle deposition on the filter (19a) to aid analysis. Particle losses of less than 1% for particles in the 0 to 20 micron range may be realized.

Inventors:
 [1]
  1. Oakland, CA
Issue Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
864046
Patent Number(s):
4301002
Assignee:
United States of America as represented by United States (Washington, DC)
Patent Classifications (CPCs):
G - PHYSICS G01 - MEASURING G01N - INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
B - PERFORMING OPERATIONS B07 - SEPARATING SOLIDS FROM SOLIDS B07B - SEPERATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, OR SIFTING OR BY USING GAS CURRENTS
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
efficiency; virtual; impactor; environmental; monitoring; atmospheric; air; facilitated; single; stage; 11; separating; inlet; flow; particulate; contaminants; coarse; particle; fine; enable; collection; particles; filters; 19a; 19b; separate; analysis; acceleration; nozzle; 28; probe; 37; impaction; 41; aligned; axis; 13; spaced; apart; define; separation; region; 14; drawn; radially; outward; chamber; 21; enters; symmetrical; outlet; means; 47; provide; symmetry; assure; precise; cutpoint; size; minimize; losses; wall; gravitational; settling; impulse; defocusing; 42; provides; uniform; deposition; filter; 20; micron; range; realized; provides uniform; virtual impactor; particulate contaminants; particle collection; coarse particle; atmospheric air; outlet means; particle deposition; spaced apart; radially outward; single stage; collection probe; separation region; fine particle; micron range; environmental monitoring; flow separation; focusing means; inlet flow; particle accelera; /209/73/

Citation Formats

Loo, Billy W. High efficiency virtual impactor. United States: N. p., 1981. Web.
Loo, Billy W. High efficiency virtual impactor. United States.
Loo, Billy W. Thu . "High efficiency virtual impactor". United States. https://www.osti.gov/servlets/purl/864046.
@article{osti_864046,
title = {High efficiency virtual impactor},
author = {Loo, Billy W},
abstractNote = {Environmental monitoring of atmospheric air is facilitated by a single stage virtual impactor (11) for separating an inlet flow (Q.sub.O) having particulate contaminants into a coarse particle flow (Q.sub.1) and a fine particle flow (Q.sub.2) to enable collection of such particles on different filters (19a, 19b) for separate analysis. An inlet particle acceleration nozzle (28) and coarse particle collection probe member (37) having a virtual impaction opening (41) are aligned along a single axis (13) and spaced apart to define a flow separation region (14) at which the fine particle flow (Q.sub.2) is drawn radially outward into a chamber (21) while the coarse particle flow (Q.sub.1) enters the virtual impaction opening (41). Symmetrical outlet means (47) for the chamber (21) provide flow symmetry at the separation region (14) to assure precise separation of particles about a cutpoint size and to minimize losses by wall impaction and gravitational settling. Impulse defocusing means (42) in the probe member (37) provides uniform coarse particle deposition on the filter (19a) to aid analysis. Particle losses of less than 1% for particles in the 0 to 20 micron range may be realized.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1981},
month = {1}
}