The presteaming bin is a chip bin for allowing buffer storage and presteaming of the raw material.
The bin is of a hopper design and consists of a cylindrical and conical top section and a conical bottom section. The raw material enters the bin at the top and leaves through the conical bottom section.
In the conical bottom section a vibrating cone is inserted to help prevent bridging of the raw material in the bin. The preheated steam is introduced below this cone and distributed both in the middle and around the periphery of the bin where it meets the raw material passing down between the cone and the bin wall. The bin is designed for 15 to 20 minutes retention time.
- Pretreatment of the raw material by steam at an elevated temperature for a certain time
- Moisture increase of the raw material
- Reduction of natural wood resins
- Improved dewatering in the screw feeder