Hi-Vol Cascade Impactor

PRINCIPLE OF OPERATION
Suspended particles enter a high volume air sampler and pass through the parallel slots in the first impactor stage. Those particles larger than the particle cut-off size of the first stage impact on a slotted collection substrate. The air stream passes through the slots of the substrate and accelerates as it flows through the narrower parallel slots of the second impactor stage. The remaining particles that are greater than the particle cut-off size of the second stage impact on the second collection substrate and so on through the remaining stages of the impactor.

The width of the slots is constant for each stage, but narrower for each succeeding stage and eventually most of the particles acquire a sufficient momentum to impact on one of the collection substrates. The back-up filter holder of the hi-vol sampler collects the remaining small particles passing through the last impactor stage. The final filter and collection substrates are weighed before and after sampling to determine the gain in mass and subsequent particle size distribution. All particles are collected allowing for determination of total particle concentration.

APPLICATIONS

• Determine respirable particle mass
• Particle transport studies
• Efficiency of air pollution control equipment

The unique slotted impactor design provides the ultimate in precision, predictability and sharpness of cut-off combined with compactness, ease-of-use and the lowest internal losses.

Particles are sized aerodynamically

Specifications