Drum drier

Principle

A heated hallow metal drum rotates on its longitudinal axis, which is partially dipped in the solution to be dried.

The solution is carried as a film on the surface of the dryer &

Dried to form a layer. A suitable knife scraps the dried material, while drum is rotating

Construction

• It consist of a horizontally mounted hollow steel drum of 0.6 – 3.0 meters diameter & 0.6 – 4 meters in length, whose external surface is polished.

• Below the drum, feed pan is placed in a such way that the drum dips partially into the feed.

• On one side of the drum a spreader is placed & on other side a doctor’s knife is placed to scrap the dried material

• A storage bin is placed connecting the knife to collect the material

Working

• Steam is passed inside the drum. Drying capacity is directly proportional to the surface area of the drum. Heat is transferred by conduction to the material

• Drum is rotated at a rate of 1- 10 revolutions per minute. The liquid material present in the feed pan adheres as a thin layer to the external surface of drum during its rotation

• Material is completely dried during its journey in slightly less than one rotation. the dried material is scrapped by knife, which then falls into a storage bin. The time of contact of the material with the hot metal is 6-15 seconds only