| 摘要 |
PURPOSE:To permit the reduction of noise generated out of a discharging port by providing a chamber, larger than the discharging port, near the discharging port at the tip end of the ventilating passage of a duct. CONSTITUTION:When the operation of an air-conditioning machine 1 is started, air, sent out of a fan 3, flows through the inside of a duct and sound is generated. Sound wave has straight-going property and, therefore, sound wave travels straightly through the inside of the duct 4. Then, a chamber 6, larger than a discharging port 5, is provided near the discharging port 5 to hit the sound wave, advanced straightly through the duct 4, against the wall of the chamber 6 and attenuate the sound in the chamber 6. When the chamber 6 is same as or smaller than the discharging port 5, sound deadening effect is small and, therefore, the chamber 6, larger than the discharging port 5 as much as possible, is provided. Thus, the noise, generated out of the discharging port can be reduced. |
