Pneumatic Conveying Overview

Dense Phase - Full Pipeline

The difference in pressure is higher

Material velocities are at their lowest

Material fills the pipeline

Dense Phase - Slug Flow

The difference in pressure is medium-high

Material velocities are low

Material forms dunes while being conveyed

Dense Phase - Bed Flow

The difference in pressure is medium

Material velocities are medium to high 

The saltation velocity is achieved for some particles in the material which partially fluidizes to convey above a bed of material moving slower

Lean Phase (Dilute Phase)

The difference in pressure is lower

Material velocity is highest

The saltation velocity for all the particles is achieved which causes the material as a whole to be conveyed within the gas stream