Air classifying

Air classifying is suitable for high volume processing where a single product cut is required, to remove oversize or fines, typically between 10 and 300 microns. It is therefore capable of a smaller particle size cut than sieving.
The accuracy of cut achieved is very material dependent and requires extended development time.
Material is air conveyed into the classifier. This process is best suited to free flowing powders but sometimes it can accommodate cohesive powders. The vigorous air conveying and classifier action makes this process less suitable for hygroscopic or friable materials.
Once the material enters the classifier an adjustable but static baffle system combined with variable speed classifier wheel achieves the separation. Fine material passes out of the classifier with the air flow and is separated in a filter unit, from where it can be packed into big bags or sacks. Oversize drops out of the air flow in the classifier and is discharged via a rotary valve. Air classifying is commonly used in Protein Shifting where precise particle size control is essential to provide consistent high protein content in the fine fraction.
Air classifying is offered from three process units with standards from industrial to FSSC22000 food grade.