The storage and feeding of solids is a basic requirement for the operation of a wide spectrum of industries.

Fundamental of any bulk storage situation is the understanding of the flow patterns that develop when bulk materials are filling into, or emptying from, hoppers. Structural aspects are affected by how the material exerts pressure on the container. Features, such as the size of outlet required, the maximum and minimum residence time of the material in store for given discharge sequences, the prospects of segregation and whether some material will remain static from the first hopper fill until the final emptying of all the contents, all depend upon the form of flow pattern which takes place.