The working principle of a wood pellet machine is to compress loose wood sawdust into high - density pellets through mechanical force. The core processes include raw material pre - treatment, extrusion molding, and pellet cutting.
Main working steps:
1. Raw material pre - treatment:
The wood sawdust need to be screened first (to remove impurities) and dried (with the moisture content controlled between 10% - 20%). This ensures that the raw materials have a uniform texture and appropriate humidity, preventing any negative impact on the molding effect.
2. Extrusion molding:
The treated wood sawdust are fed into the feed inlet of the pellet machine and then flow into the granulation chamber. Inside the granulation chamber, there is a ring die and rollers. When the rollers rotate, they squeeze the wood sawdust into the small holes of the ring die. The high temperature (about 80 - 120°C) generated by the extrusion softens the lignin in the wood sawdust, which acts as a natural binder. This allows the wood sawdust to stick together and take shape under pressure, extruding from the small holes of the die in a cylindrical shape.
3. Pellet cutting:
The extruded cylindrical material is cut into pellets of a set length by a cutter installed on the outer side of the die, and finally discharged through the discharge port.
