Principle Of Operation; Media Preparation - SKC Reusable Parallel Particle Impactor Operating Instructions Manual

Principle of Operation

SKC Reusable PPI Samplers are impaction-based
fi lter samplers that perform precise size selection
for either thoracic or respirable dust, depending
on the model. PPI Samplers contain four small
impactors in the inlet section of the device.
Each impactor features a unique 50% cut-point
to target a specific one-quarter segment of the
ISO/CEN curve resulting in a precise fit along
the entire curve. A sample pump operating at
2, 4, or 8 L/min (2 L/min only for thoracic) pulls
air through the inlet nozzle of each impactor
in the inlet plate. Particles larger than each
impactor's 50% cut-point are scrubbed and
retained by impaction onto the porous oiled
impaction substrate contained in each impactor.
Smaller particles continue to the standard
37-mm collection filter for analysis. See
www.skcinc.com/prod/225-380.asp and click on
More Information for performance graphs.

Media Preparation

Filters: Condition and weigh fi lters according to method used. Record the weight as
the pre-sample weight.
Impaction Substrate: Using an oiled impaction substrate reduces particle
bounce. Replacement pre-oiled disposable porous plastic discs are available as SKC Cat. No.
225-388. See Ordering Information.
Inserting a Collection Filter into the PPI
The PPI will arrive already assembled. Disassemble it to
insert collection fi lter.
1. Unscrew and remove two screws that hold the inlet
plate to the base plate.
2. Lift off inlet plate to expose impaction plate.
3. Lift off impaction plate to expose base plate.
Dust enters here
2
Inlet plate
Impaction
substrates (4)
Standard 37-mm
collection fi lter
and support pad
Base plate with
exhaust to pump