Rotary dryer

[1] The dryer is made up of a rotating cylinder ("drum" or "shell"), a drive mechanism, and a support structure (commonly concrete posts or a steel frame).

Gas flow, heat source, and drum design all affect the efficiency and suitability of a dryer for different materials.

The direction of gas flow combined with the inclination of the drum determine how quickly material moves through the dryer.

If the hot gas stream is made up of a mixture of air and combustion gases from a burner, the dryer is known as "directly heated".

The addition of a combustion chamber at the feed end helps ensure efficient fuel usage, and homogenous drying air temperatures.