1.Types of Flat-die Pellet Mills
 
    There are three type of Small Pellet Mills: they are roller-moving pellet mill, ring die-moving pellet mill, roller and ring die moving simultaneously pellet mill. The latter two types are small pellet mills, and the roller-moving is always the big ones.
Depends on the shape of the roller, they can be spell into two types: Taper Roller type and straight roller type.
 
2. The Working Principle of the Straight Roller Type Flat-die Pellet Press
 
    The electromotor drive the principal axis through the reducer casing , then the axis move the roller, the roller revolute with the axis, and rotate by itself. When produce the pellets, the raw material were send into the feed case, then lay evenly on the ring die under the effect of distributor and the blade, then the principal press the material, extruding the material into the hole, the raw material was pressed into pellets, and cut by the knife, finally blade out.
 
3.The Roller Molding Principle of flat-die Pellet Mill
 
    Fibrin, semi-fibrin and lignin are the main material of the biomass raw material. And in the process of pelletization, raw material of the feed area is cling to the ring die under the effect of the gravity, when the roller works, material was press into the hole of the ring die, and the air in the hole was discharged, and the mutual alignment of the particles are changed continuously. All the gaps between the gaps was entered by the big particle. As the roller keep going, the compacted material was delivered into the molding area, such as wedge-shape area, bore-hole area and the front part , they are all belong to  molding area, in this space, pressure increased, the particles become transformation and plastic flow, then extend to the biggest power, and filling the around gaps. It is very hot which lead by the rubbing effect of the roller and material, and soften the lignin, make it more adhesive. The combine effect of soft lignin and the fibrin make the biomass material become pellets. And the pellets are press into the keep shape space, then the pellets are final designed.
 
    In the roller moving flat die pellet mill, the ring dies are fixed in theengine base, the biomass material is squeeze out from the hole, and cut into customized pellets. This kind of immobile working style is making for improve the ratio of briquetting.
 
    As the core working spares, the parameter of the ring die affect the quality of the pellets directly. Process different material needs different ring die. The holes area, size, and configuration style are the elements decide the performance of the pelletization. Smaller draw ratio of the right die, bigger the output, but the quality of the pellet is worse. Vice versa, the quality of the pellets is better.
 
    From the working experience, same material need same size product, and the thickness is thinner.
 
4.Charateristics  of the Flat-die Pellet Mill
 
● simple structure, small size, low cost.
● ring die is the wear-out part, need to be changed regularly
● The ring die could be used two-sided, if one side is abrased then use another side, which not only increase the service life, but also reduce the production cost.