SKC 100-3901 DPS (Deployable Particulate Sampler) System - Manual (Page 6)

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PRINCIPLE OF OPERATION
A sample pump draws particle-laden air at a fl ow rate of 10 L/min through an in-
ertial impactor to separate airborne particles according to aerodynamic diameter.
Particles enter the impactor through eight nozzles on top of the sampler. The inlet
nozzles are sized to operate at a 10 L/min fl ow rate causing eight airjets to impinge
onto the impaction disc positioned below the inlet nozzles. Particles larger than
the sampler cut-point with enough inertia to cross the airstream lines impact on
the impaction disc. The airfl ow, containing smaller particles, makes a sharp turn,
passes through the openings in the top of the fi lter cassett e, and follows through
to a 47-mm fi lter where the smaller particles collect.
The top of the fi lter cassett e accommodates the impaction disc. For optimum impac-
tor performance, a 37-mm oiled porous plastic disc is recommended as disposable
collection substrate (supplied with system). If chemical analysis of larger particles
is desired, a 37-mm fi lter (quartz or PTFE) may be used.
Inlet
PTFE O-ring
Impaction disc
BUNA-N O-ring
Exhaust
IMPACT Sampler and Leland Legacy
Sample Pump - the two main components of
the DPS System
Exploded view of IMPACT Sampler
Rain cover
Air
fl ow
Air
fl ow
Air
fl ow Air
fl ow
Air
fl ow
Filter cassette top
Collection fi lter
Stainless steel support
Filter cassette bottom