Patent ID: 6955526

Claim:
A vacuum generator, comprising: an air-supply port to which compressed air is supplied; a nozzle from which the compressed air is jetted toward a diffuser nozzle so as to suck air from a vacuum port; and an air-discharge port from which the compressed air is discharged, said nozzle including a first venturi nozzle and a second venturi nozzle, said second venturi nozzle having a diameter greater than that of said first venturi nozzle; a first communication path communicating said air-supply port to a base end of said first venturi nozzle such that suction air from the vacuum port flows through the first venturi nozzle and through the second venturi nozzle; a second communication path communicating said air-supply port to a base end of said second venturi nozzle such that suction air from the vacuum port flows only through the second venturi nozzle; and means for switching a state of said vacuum generator between a first state, in which said air-supply port is connected to said first communication path so as to suck a small amount of air from said vacuum port, and a second state, in which said air-supply port is connected to said second communication path so as to suck a large amount of air from said vacuum port, wherein said first venturi nozzle, said second venturi nozzle and said diffuser nozzle are serially arranged in that order.