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Cotton dust sampling efficiency of the vertical elutriator
American Industrial Hygiene Association Journal
|June 1, 1979
Summary
A new computer model (VELUT) simulates vertical elutriator air samplers, revealing they collect cotton dust fibers more effectively than previously thought. This model accurately predicts sampling efficiencies for various dust distributions.
Area of Science:
- Environmental Engineering
- Industrial Hygiene
- Aerosol Science
Background:
- Vertical elutriators are used for air sampling, particularly for respirable dust.
- Previous models may not have accurately captured the elutriator's performance across all particle sizes.
Purpose of the Study:
- To develop and validate a theoretical model for vertical elutriator air samplers.
- To predict the sampling efficiency of vertical elutriators for cotton dust.
Main Methods:
- A theoretical model based on flow separation at the inlet was developed.
- The model's equations were simulated using a computer program named VELUT.
- The model was calibrated against experimental data for isokinetic sampling efficiencies.
Main Results:
- The calibrated model predicted a 50% differential efficiency at approximately 20 micrometers, not a sharp cutoff at 15 micrometers.
- Substantial collection efficiencies were predicted for particles in the aerodynamic size range of individual cotton fibers.
- Program VELUT provides an objective method to calculate isokinetic sampling efficiency for any dust distribution.
Conclusions:
- The VELUT model offers a more accurate representation of vertical elutriator performance.
- Vertical elutriators may collect a significant fraction of larger cotton dust fibers.
- The model can be used to assess sampler performance for various airborne dust scenarios.