Modern industry has found a successful use for vacuum generators in a wide range of applications, ranging from vapour extraction to pick and place operations and bulk materials handling. Electrically driven vacuum pumps generally used to be four times more energy efficient than vacuum generators driven by compressed air, depending on how high a level of vacuum and flow was required, and how constant was the delivery. New generation pneumatic systems with electronic sensors, however, have delivered more compact and energy efficient units, which can also be used in areas without an electrical supply.
Most compressed air vacuum generators function on the venturi principle. A pressure supply port provides a compressed air flow into an ejector, with a constriction in the venturi nozzle that massively increases the air flow velocity. On exiting the constriction, the air expands again and flows out through a receiver nozzle into an outlet port, creating a vacuum in the chamber between the two nozzles. This vacuum then causes more air to be drawn in from a vacuum port. Both the exhaust air and this vacuumed air exit through the outlet port, which also functions as a silencer.
Very low vacuum levels can be obtained from multi-stage units, depending on their suction flow, and generators can be used as stand-alone units or connected via a manifold. Modern compact vacuum generators can be customised in order to integrate additional components such as vacuum sensor switches, suction filters, and supply/release valves.