It is also called Air Activated Conveyor or Pneumatic Gravity Conveyor. It is essentially a rectangular duct divided into an upper part (dirty chamber) and a lower part (clean chamber).

Material is fed through the upper part of the porous media. Pressurized air is introduced through the lower part or clean chamber.

The air penetrates through the porous media and fluidizes the material allowing it to slide or flow and creates a continuous flow from the inlet to the outlet.