| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a blower capable of suppressing the whole length becoming long by suppressing pressure loss between an active silencer and a centrifugal fan and also by suppressing drop of a silence effect of the active silencer due to a standing wave.SOLUTION: A blower includes: a centrifugal fan 7; a duct-like active silencer 8 including a reference microphone 12 and an error microphone 14 for detecting a sound wave, and a speaker 13 for emitting the sound wave, at each of a plurality of small air passages 11; and a ventilation flue 10 for connecting an outflow port 9 of the active silencer 8 and a suction port 2 of the centrifugal fan 7. An central axis 19 of each small air passage 11 is vertical with respect to a suction axis 20 vertical to the suction port 2, and the central axes 19 are arranged adjacently in parallel at an upstream side and a downstream side in the suction axis 20 respectively. The outflow port 9 of the small air passage 11 arranged on the upstream side is brought closer to the suction axis 20 than the outflow port 9 of the small air passage 11 arranged on the downstream side, and an outer wall surface 17 of the small air passage 11 arranged on the upstream side faces the suction port 2.</p> |
