TSI Instruments 3076, Instruction Manual

Page: 41 / 63

Atomizer Applications 5-7
The suspension is aspirated through the 1
⁄
16
-inch-diameter tube
from an open reservoir and excess suspension is returned to the
same reservoir. A sonic probe
*
is used to continuously disperse the
particles in the hydrosol reservoir. Results show that the aerosol
consists mainly of primary particles—the agglomerates that are
fused together by the carbon black manufacturing process—and
that the level of agglomerates is very low.
An alternate method, which uses the bottle in the recirculation
mode, is to deagglomerate the particles with a sonic probe for
several minutes and then stir the suspension with a magnetic
stirrer while atomizing. This allows the bottle to be sealed to the
Atomizer head. The exact length of time particles remain in
suspension (several hours), depends on their size and density.
The performance of the Atomizer was checked according to the
method described by Liu and Lee (see Appendix B of this manual).
The most important factors for quality atomizing are (a) drying and
neutralizing the aerosol; and (b) diluting the aerosol to the desired
concentration. If the silica gel in the dryer is not dry enough, you
may notice a gradual increase in the output of the aerosol detector.
*
Sonicator
®
3000, Misonix Inc, 1938 New Highway, Farmingdale, NY 11735 or
equivalent product from other manufacturers.