A screw conveyor is a simple yet highly efficient machine that relies on a motor to drive a screw and transport materials in a precise manner. The machine can operate in varying directions, including horizontal, oblique, and vertical orientations. Its key benefits include a small cross-sectional area, good sealing, ease of use, and low maintenance requirements to ensure closed transportation. There are two primary types of screw conveyors available: shafted and shaftless, both of which come in different structural designs such as U-shaped or tubular screw conveyors. Shafted screw conveyors are ideal for non-sticky dry powder and small granular materials, but there are also other variants suited for specific conveying challenges.
The fundamental principle behind the screw conveyor lies in the rotational motion of the blade, which effectively propels material along the conveyor. This motion prevents the material from rotating with the screw blade and relies on two main forces: the weight of the material itself and the frictional resistance between the casing and the material. The spiral blade, securely welded to the rotating shaft, comes in different surface types like solid, belt, and blade surface, catering to the specific requirements of various conveyed materials. To counterbalance the axial force exerted by the material, the screw shaft is equipped with a thrust bearing at the end in the direction of material movement. In cases where the machine's length is considerable, the addition of an intermediate hanging bearing becomes necessary.