High efficiency virtual impactor

Patent · Thu Jan 01 04:00:00 EST 1981

OSTI ID:864046

Loo, Billy W ^[1]

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1. Oakland, CA

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.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• DOE Contract Number: W-7405-ENG-48
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4301002
• OSTI ID: 864046
• Country of Publication: United States
• Language: English

Related Subjects

/209/73/
11
13
14
19a
19b
20
21
28
37
41
42
47
acceleration
air
aligned
analysis
apart
assure
atmospheric
atmospheric air
axis
chamber
coarse
coarse particle
collection
collection probe
contaminants
cutpoint
define
defocusing
deposition
drawn
efficiency
enable
enters
environmental
environmental monitoring
facilitated
filter
filters
fine
fine particle
flow
flow separation
focusing means
gravitational
impaction
impactor
impulse
inlet
inlet flow
losses
means
micron
micron range
minimize
monitoring
nozzle
outlet
outlet means
outward
particle
particle accelera
particle collection
particle deposition
particles
particulate
particulate contaminants
precise
probe
provide
provides
provides uniform
radially
radially outward
range
realized
region
separate
separating
separation
separation region
settling
single
single stage
size
spaced
spaced apart
stage
symmetrical
symmetry
uniform
virtual
virtual impactor
wall