The use of moving air to separate and classify particles is a feature in many bulk material handling applications, with a key tool for such classification being the humble air classifier. The working principle for these machines involves separating a material’s particles according to density, shape, and size. Air classifiers are commonly employed for industrial processes involving bulk materials, especially in cases where particles can differ significantly in their physical characteristics.
Though models may have different design features depending on their application, air classifier working principles always rely on two forces: a force associated with air drag and a force that depends on inertia, often referred to as centrifugal force. Air drag becomes more prevalent as particles are reduced in masse during processing. Separation occurs as particles with lower masses are more easily carried along the air stream. These finer particles are drawn up via moving air, which is then carried away from the zone in which the particles are classified(Air Classifier Working Principle, n.d.).
Air classifier working principles are as follows:
- Material enters the classification area where airflow rises.
- Other particles with greater mass drop into the secondary air chamber.
- This secondary air inlet again separates coarse from fine particles.
- Material that doesn’t meet requirements is rejected and discharged at the air classifier’s base.
Reference:
Air Classifier Working Principle. (n.d.). Retrieved June 4, 2025, from https://blog.praterindustries.com/air-classifier-working-principle
