A flash dryer is used to dry residual moisture from centrifuged cakes or powders.

Drying process is accomplished by contacting the powder with hot air travelling at high velocity. The heat is used for drying and the air pneumatically conveys the powder for separation in a cyclone or a bag filter. A product classifier ensures only dry powder leaving the drying chamber.

A modified version of a flash dryer is a Ring Dryer and incorporates a centrifugal classifier that uses deflector blades to select and classify air borne particles on the basis of their densities. As a result of centrifugal action, the behavior and wetter particles follow the ring duct periphery more closely and are recycled back, while the fine dried material leaves the dryer with the exhaust air to be collected in the cyclone or bag filter before being scrubbed in a venturi scrubber.