Vacuum conveying systems operate in reverse to a lean phase, positive pressure system where material is transferred from source to destination via a vacuum pump or inverse blower. Air is sucked out of the transfer pipe line which causes a vacuum and therefore pulls the material along. This type of transfer system can also be utilised for both batch and continuous production systems.

Vacuum transfer systems generally utilise rotary valves or similar feeding system to control the flow of material into the line and normally incorporate a filter or cyclone unit on the receiving vessel to separate transferring air from material.