Procesy technologiczne prowadzone w aparatach bębnowych dla materiałów ziarnistych

Rotary drums are used in many industrial branches, such as: mixing, grinding, granulating, sieving and drying of granular materials. The widespread use of rotary drums is due to their simple design and operating principle - a rotating drum moving bed. But for the processes described in the paper a proper movement of the bed is different. The first move appears at the lower velocity, so the bed only slips. The second appears when the angle-of-repose is achieved and particles start rolling. During the next move, which is cascading, the so-called "kidney" is created. Particles are stationary in the central kidney but on the outside they circulate. While velocity still increases, the bed loosens up and particles start an autonomous move, that is cataracting. The last move characteristic to the bed is centrifuging. The bed swirls around the drum perimeters, which is when gravitation and centrifugal forces are balanced.