Pre-steaming bin with vibrating discharger

Efficient heating of chips from the pre-steaming temperature to the cooking temperature

Why pre-steaming?

The temperature differential between the bin and cooking in the vertical digester decreases when chips are heated in a pre-steaming bin.

Any condensate forming in the pre-steaming bin can easily be squeezed out in the plug screw feeder and the chips have only to be heated up from the pre-steaming temperature to the cooking temperature. This drastically reduces condensate in the vertical digester which then does not have to be evaporated in the dryer. As a result, energy consumption in the dryer is considerably reduced.


Closed bin design of the ANDRITZ pre-steaming bin

The ANDRITZ pre-steaming bin is designed as a closed bin made of stainless steel. To ensure easy accessibility, a manhole is located on the top which can only be opened with a special tool.


  • Continuous pre-steaming of the raw material
  • Can be used as storage bin
  • Volume of the bin designed according to plant capacity and required retention time
  • Continuous level control by three load cells and a maximum level switch

No loss of steam with the ANDRITZ vibrating discharger unit

The ANDRITZ vibrating discharger unit is attached to the pre-steaming bin with springs and a special rubber seal to ensure no loss of steam from the pre-steaming process. The vibrating discharger moves pre-steamed chips continuously out of the bin to maintain a continuous flow to the plug feeder.


  • Continuous discharge without bridging
  • Online adjustable vibrating ratio (depending on raw material)
  • Steam connection from the bottom for optimized steaming/pre-heating efficiency to prevent steam channeling and ensure even moisture profile