As the helical shaft rotates, the material-constrained by its own weight and the friction generated against the trough walls-is compelled to advance along the bottom of the conveyor trough solely under the thrust of the helical blades. This phenomenon is analogous to a non-rotating nut undergoing translational motion along a rotating screw. The primary driving force propelling the material forward stems from the action of the rotating helical blades, which exert an upward and forward force on the material along a tangential trajectory relative to the blade surface.
To ensure the helical shaft remains in a more favorable state of tension, the drive mechanism and the discharge port are typically positioned at the same end of the conveyor, while the feed port is situated as close as possible to the tail end of the opposite side. The rotating helical blades convey the material by pushing it forward; the forces preventing the material from rotating in unison with the blades are the material's own weight and the frictional resistance exerted by the conveyor casing. Depending on the specific material being conveyed, the helical blades may feature various surface configurations, such as solid-surface, ribbon-type, or paddle-type designs. At the terminal end of the helical shaft-in the direction of material flow-the screw conveyor is equipped with a thrust bearing to absorb the axial reaction forces exerted by the material upon the screw; for conveyors of considerable length, intermediate hanger bearings should also be installed.
