Principle Of Operation - SKC Preloaded Disposable Parallel Particle Impactor Operating Instructions Manual

Principle of Operation

SKC Disposable 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 specifi c one-quarter segment of
the ISO/CEN curve resulting in a precise fi t 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 fi lter for analysis.
Protective
end cap
Exhaust
to pump
Base plate
PPI Performance
Collection effi ciency of the 2, 4, and 8 L/min
respirable PPI Samplers compared to the
ISO respirable curve
Dust enters here
thoracic PPI Sampler compared to the
3
Inlet plate (contains 4 impac-
tors with unique cut-points
preloaded with 4 impaction
substrates and sonically
welded)
Standard 37-mm collection
fi lter (assembled)
37-mm support pad
(assembled)
Collection effi ciency of the 2 L/min
ISO thoracic convention
Collar clip