Cascading Rotary Dryers

The Cascading Rotary Dryers have the feed materials pass through a rotating cylinder together with a stream of hot gas. Internal lifters or flights elevate the feed and drop it in a curtain from the top to the bottom cascading along the length of the dryer. Flights need to be carefully designed to prevent asymmetry of the curtain. Material moves from one end of the dryer to the other by the motion of the material falling due to the angle of inclination of the drum. Some rotary dryers are double and triple pass units where each drum is nested inside the previous drum.
Granular free flowing wet feed material is made to shower repeatedly in a cascade manner in a stream of hot air, when moisture gets transferred to the air, rendering the product progressively dry as it travels the length of the dryer cylinder provided with suitable lifters. The humid air is exhausted via a dust collection system to trap any fines escaping with the exhaust air.