Abstract

When work on the development of the theory of bulk solids flow began in the early 1950s, bulk solids were thought to behave much like liquids, and thus were expected to flow easily from bins. Powder flow is not always reliable, however. The field of bulk solids flow has since been developed to allow design of equipment and testing methods.

Typical flow problems include no-flow (arching, ratholing), erratic flow, flooding, limited discharge rate, and segregation. Flow patterns experienced by bulk solids include funnel flow, which occurs when some of the material in a bin moves toward the outlet while the rest remains stationary; mass flow, where all of a material is in motion whenever any is withdrawn; and expanded flow, which uses the best aspects of funnel flow and mass flow.

Equipment design, maintenance, and special considerations including sifting, particle velocity, and entrainment are discussed.