TSI Instruments 3082, Operation And Service Manual, Page: 134 / 225

5-46 Electrostatic Classifier Model 3082 and SMPS Spectrometer Model 3938
Impactor Flow
Aerosol flow rate is measured by the impactor by measuring the differential
pressure (dP) across the impactor orifice. Since the measurement is based
on dP it is sensitive to inlet gas conditions, and; therefore, the impactor
should be recalibrated if your inlet gas conditions are much different than
the conditions shown on the impactor’s Certificate of Calibration received
from the factory. To perform an Impactor flow calibration, follow these
instructions:
1. Install the impactor that
you wish to calibrate.
The impactor must be
fully assembled (with
impaction plate).
2. Connect the
Polydisperse Flow
outlet to the Sheath
Flow
–
port on the side
of the classifier using
lengths of ¼-inch and
3/8-
inch tubing. A 3/8”-
to-
1/4” reducing tube
adapter (not provided)
may be necessary to
ensure a good
connection between the
two lengths of tube.
3. Disconnect tubing from
the Sheath Flow + port
on the classifier so that
it is open to ambient.
4. Connect a reference
flowmeter to the inlet
of the impactor. The
Reference flowmeter
should have an
accuracy of
±
2% or
better over the range
of 0.2 to 2.0 L/min,
such as a Gilibrator
®
meter.
5. From the classifier
Setup screen >
Calibration > User
Calibration > the
Impactor Flow tab.
The SN: (serial
number) and Size:
(impactor size) fields
are automatically
populated.