Patent ID: 7415980

Claim:
A suction device comprising: a fine particle generating nozzle for generating fine particles of a substance to be sprayed by pulverizing the substance to be sprayed made of liquid by a gas; a separating vessel for separating the fine particles generated by the fine particle generating nozzle; a delivery section for delivering, only during suction, superfine particles separated from the fine particles in the separating vessel; a particle size setting means for setting a particle size of the superfine particles to be delivered from the delivery section; a particle size detecting means for detecting a particle size of the superfine particles to be delivered from the delivery section; a first gas pressure control means for controlling a pressure of a gas to be fed to the fine particle generating nozzle such that the particle size of the superfine particles detected by the particle size detecting means is equal to the particle size of the superfine particles set by the particle size setting means; a secondary gas feeding means for feeding a secondary gas for increasing the fine particles in the separating vessel into the separating vessel; and a second gas pressure control means for controlling a pressure of the secondary gas to be fed by the secondary gas feeding means such that the particle size of the superfine particles detected by the particle size detecting means is equal to the particle size of the superfine particles set by the particle size setting means.