Packaging Powders: A Double Challenge

Processors of powders are faced with two interesting problems that can be solved with physical test instruments. The first is the potential jamming of the powder in vertical discharge from a hopper which feeds a metering augur or conveyor. The second is the package or container that receives the powder in a filling process, which is then sealed and transported for distribution to customers. Will the powder stay loose and free flowing or will it consolidate? Powdered beverage mixes for consumer use and processed cocoa are two good examples. The former is fed into flexible pouches or packets while the latter is fed into bags or sacks; all may have variable size.

Flow behavior of powders in gravity feed hoppers is not well understood scientifically by many in industry. One technique for coping with powder jams is to physically beat the hopper with enough frequency and force, usually a hammer or mallet, in order to dislodge the packed powder inside. The powder has become packed because it naturally tends to consolidate or settle due to its own self weight in the bin.