Method for sampling sub-micron particles

Patent · Tue Jan 01 04:00:00 EST 1985

OSTI ID:865523

Gay, Don D ^[1]; McMillan, William G ^[2]

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1. Aiken, SC
2. Ulmers, SC

Apparatus and method steps for collecting sub-micron sized particles include a collection chamber and cryogenic cooling. The cooling is accomplished by coil tubing carrying nitrogen in liquid form, with the liquid nitrogen changing to the gas phase before exiting from the collection chamber in the tubing. Standard filters are used to filter out particles of diameter greater than or equal to 0.3 microns; however the present invention is used to trap particles of less than 0.3 micron in diameter. A blower draws air to said collection chamber through a filter which filters particles with diameters greater than or equal to 0.3 micron. The air is then cryogenically cooled so that moisture and sub-micron sized particles in the air condense into ice on the coil. The coil is then heated so that the ice melts, and the liquid is then drawn off and passed through a Buchner funnel where the liquid is passed through a Nuclepore membrane. A vacuum draws the liquid through the Nuclepore membrane, with the Nuclepore membrane trapping sub-micron sized particles therein. The Nuclepore membrane is then covered on its top and bottom surfaces with sheets of Mylar.RTM. and the assembly is then crushed into a pellet. This effectively traps the sub-micron sized particles for later analysis.

• Research Organization: E I DUPONT DE NEMOURS & CO INC
• DOE Contract Number: AC09-76SR00001
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4530250
• OSTI ID: 865523
• Country of Publication: United States
• Language: English

Related Subjects

/73/62/95/
accomplished
air
analysis
apparatus
assembly
blower
bottom
bottom surface
bottom surfaces
buchner
carrying
carrying nitrogen
chamber
changing
coil
coil tubing
collecting
collecting sub-micron
collection
collection chamber
condense
cooled
cooling
covered
crushed
cryogenic
cryogenic cooling
cryogenically
cryogenically cooled
diameter
diameters
drawn
draws
draws air
effectively
effectively traps
equal
exiting
filter
filters
form
funnel
gas
gas phase
heated
ice
liquid
liquid form
liquid nitrogen
melts
membrane
method
method steps
micron
micron size
micron sized
microns
moisture
mylar
nitrogen
nuclepore
particles
particles therein
passed
pellet
phase
rtm
sampling
sheets
sized
sized particles
standard
steps
sub-micron
sub-micron particle
sub-micron sized
surfaces
therein
top
trap
trap particles
trapping
traps
tubing
tubing carrying
vacuum