Explain the Rotary Dryers?

Rotary dryers are widely used to dry relatively large throughputs of granular products and by products in a number of industries, including the food industry. Rotary dryers are characterised by a slowly rotating cylindrical drum, which is normally inclined at a small angle (0 - 5°) to the horizontal. The product to be driedis introduced into the upper end and dried product is withdrawn at the lower end. There are a number of different types of rotary dryer; one of the most common is the cascading rotary dryer. Typical food products dried in rotary dryers include fish scraps, wheat residues, cocoa beans, nuts, cooked cereals, flour, sugar and spent grains.