Principles of Operations
Flow enters the inlet cowl and accelerates through the six radial slots
in the first impactor stage. The cowl eliminates ashes and debris from
the sampler. Particles larger than the cut-point of the first stage impact
on the precut collection substrate. Then, air stream flows through the
narrower slots in the second impactor stage, smaller particles impact on
the second collection substrate, and so on. The width of the radial slots
are constant for each stage but are smaller for each succeeding stage.
Thus, the jet velocity is higher for each succeeding stage, and smaller
particles eventually acquire sufficient momentum to impact on one of the
collection substrates. After the last impactor stage, remaining fine particles
are collected by the built-in 34mm filter.
Prior to sampling, collection substrates and back-up filters are weighed
and placed in the impactor. The sampling flow rate of the personal sampling
pump is set at 2 LPM. The impactor's personal mounting bracket is attached
to the lapel or pocket.
After sampling, the substrates and filter are weighed. Weight increases
on each substrate is the mass of particles in the size range of that impactor
stage. The total weight of particles on all stages and filter is added
and the percent particle mass in each size range is calculated. Respirable
particle mass fraction is determined from the particle size distribution.
Features
- The only personal cascade impactor available
- Aerodynamic range:21 to 0.4 microns with final filter
- Lightweight: 7 ounces max.
- Can be used as a personal or area sampler
- Available in a variety of stages
Applications
- Wood dust
- Coal dust
- Silica dust
- Respirable dust sampling
- Inhalation toxicology, aerobacteriology
- Indoor air pollution
- Low-cost, multi-point sampling
- Aerosol research 9
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