(under subclass 69) Processes in which solids are suspended in upward flowing gas or vapor, the upward force of the fluid on the solids being countered by gravity, resulting in the formation of a zone in which the particles are compacted into a dense phase; see Glossary.
(1) Note. The particles are in a state of hindered settling and the dense bed resembles a boiling liquid and above this dense bed some solids may be suspended in a dilute or dispersed phase.
