Indirect Cooling Drums


Indirectly acting cooling drums are used to cool down hot solids from calcination drums and rotary kilns and make it possible to recover thermal energy very effectively.

Many bulk materials, such as powder or granular bulk materials, need to be cooled down before being processed further. Indirect cooling is a very effective alternative to direct/convective cooling as a result of the fact that it can be used to recover thermal energy.


In indirect cooling, the hot solid is moved on one side of a partition wall while the air cools down the wall from the other side, meaning that the air never comes into direct contact with the bulk material.

Due to the large temperature differentials, a very effective transfer of heat from the hot material to the cooling air is achieved through the cooling tube walls.

Ideal for: Cooling down titanium dioxide (type RKT), cooling down calcined gypsum (type KTR)


  • Heat recovery from the hot solid
  • Saves primary energy and fuel
  • The investment pays for itself very quickly
  • Heavy-duty design with a long service life
  • Cooler exhaust air that is heated up, dust-free, and dry can be used in other process stages (e.g., dryers or rotary kilns)
  • Eliminates the need for filter systems for treating the hot cooler exhaust air


  • Type RKT (for high-temperature applications, i.e., 800–1,200 °C)
  • Type KTR (for low-temperature applications, i.e., 100–500 °C)
  • System RK-W: Indirect cooling of hot and very hot products


Jochen Brenk

Allgaier Process Technology

+49 (0) 7161 301-5088
+49 (0) 7161 34268


Allgaier Process Technology

Tel.: +49 7161 301-175
Fax: +49 7161 34268

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