DETERMINATION OF THE OPTIMAL AIRFLOW VELOCITY FOR FLOUR SEPARATION FROM BRAN MIXTURES BY PNEUMATIC SEPARATION
Annotatsiya
This study aimed to determine the optimal airflow velocity for recovering flour particles from bran–flour mixtures using pneumatic separation. A laboratory-scale pneumatic separator equipped with an air compressor, receiver, regulating valve, rotameter, separation chamber, and fraction collection system was designed and tested. Experiments were conducted using 100 g samples of bran–flour mixture obtained from the final stage of industrial flour milling, with airflow velocities ranging from 0.56 to 0.70 m/s. The results showed that flour recovery efficiency strongly depends on airflow velocity. At 0.56 m/s, fine-particle entrainment was incomplete, whereas excessive velocities above 0.65 m/s reduced separation selectivity due to turbulence and coarse-particle carryover. The highest efficiency was achieved at 0.62 m/s, where flour recovery reached approximately 73%. The findings confirm that optimized airflow velocity improves separation efficiency, reduces mechanical loading on sieving surfaces, and enhances the technological performance of pneumatic flour classification systems.