Screw conveyors can transport straws stably and evenly. Screw conveyor is completed closed and is not afraid of fire. Screw conveyor is easy to operate and simple structure. Low cost of manufacturing and good sealings. There can set up many feeding inlets and discharging outlets. Screw conveyors are widely applied in chemical ,building ,metallurgy,coal and cereals fields. Screw conveyors can be divided into horizontal screw conveyor, incline screw conveyor and vertical screw conveyor .All of them can transport powder, particle and small bulk materials.