Rotary dryer

What is it?

The rotating dryer is characterised by a mild treatment (low energy) of the material. Its drying system adapts to various products and uses injection of direct or indirect hot air without altering the material.

Working principle

In a rotating drum, in direct mode, the product is dried by injecting a flow of hot air, cocurrent or counter current.  While it is drying, the product follows the rotation movement of the dryer tube, and the internal elevators strike the product and make it advance gradually to the output. In indirect mode, the surface of the drum becomes the heat exchange surface for evaporation. 


The rotary dryer is used for the treatment of several materials e.g.:

  • Drying sand
  • Drying coal, clay,
  • The fertiliser industry (e.g. dryer, dipper)
  • Removing filler from limestone grit,
  • Dehydration of calcium chloride


  • Drying without altering the material,
  • Injecting air cocurrent or counter current,
  • Used for drying different materials,
  • Drying in direct or indirect mode,
  • Form of adjustable elevators,
  • Entrance cleared by spirals.