Entrainment Patterns of Screw Hopper Dischargers

Abstract

Helical Screws are commonly used to extract bulk solids from the outlet slots of hoppers. The manner in which material flows into the screw affects the flow characteristics of the hopper, residence periods of the contents in various locations, segregation, attrition and torque requirements of the screw. Regimes of motion of the solids in various sections of the equipment are outlined and a simple qualitative analysis enables predictions to be made based on material factors and screw dimensions. Consequential factors are discussed relevant to design and applications.