PURPOSE: To absorb wind breaking noise, aerodynamic sound or motor driving sound due to air flow generated in association with operation of a blower in a porous material for reduction by forming a fan of the porous material composed of granular material.
CONSTITUTION: A blower 1 is constituted of a fixed part composed of a motor 2 and a fitting part 3 of a base end part, and a fan 8 composed of a housing 5, a blade 6 and a shroud 7 and fixed to an output shaft end of the motor 2 and rotated together with the output shaft. Particularly, the fan 8 driven and rotated by the motor 2 is formed of a porous material composed of granular material. Accordingly, wind breaking noise, aerodynamic sound or motor driving sound due to air flow generated in association with operation of the blower 1 is absorbed to be reduced by the porous material forming the fan 8. Namely, the noise enters void parts in the porous material and acoustic energy thereof is converted into heat energy to be reduced.
KANNOU TATSUZOU
KONDO FUMIO
TERADA HIDEYUKI
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