This standard specifies the method for determining the particle size distribution of fine powders using an air elutriator. The method involves separating particles based on their terminal settling velocity in a rising stream of air, making it suitable for materials too fine for standard sieving.
Determination of particle size of powders by air elutriation methods
Quick Reference Values
Typical applicable particle size range5 to 75 microns
PrincipleSeparation based on terminal velocity in an upward air current
Air requirementsDry, clean, and at a constant measured flow rate
Key Formulas
V = k * D^2 — Relationship between terminal velocity (V) and particle diameter (D) based on Stokes' Law
Practical Notes
Results are highly dependent on particle shape and density, not just size.
Ensuring complete de-agglomeration of the powder sample before testing is critical for accurate results.
Maintaining a steady, non-turbulent airflow is the most important parameter to control during the test.