The preheater consists of chip inlet, tapered shell, agitator and a plug-screw feeder with feed screw, compression zone, chip and drain outlet.
The agitator is driven by an AC-motor via a worm-gear unit. The feed screw is journaled by oil lubricated bearings, and driven by a frequency controlled AC-motor via a foot-mounted gear reducer.
A stuffing box or a mechanical sealing seals the agitator shaft. The feed -screw shaft is sealed with a stuffing box