The Condenser is used for fiber separation..

In the back tape condenser, two chambers can be identified, one in depression connected to the feed duct and one at atmospheric pressure. Between the two chambers, a perforated drum rotates. The flow of material and air enters the chamber in depression, the material is retained in the duct, the perforated drum pushes the air outside through the duct, and, rotating, carries the material into the chamber at atmospheric pressure, so, no longer being held by the air, it falls from the perforated drum towards the discharge.

The back tape condenser operates in depression and must therefore be connected to the suction mouth of the fan.