| 摘要 |
A ventilation device comprises a body (11) having first and second ports (14, 15) and a ventilation passage (13) that extends through the body between the ports to allow airflow through the body. The ventilation device also comprises a noise attenuation device (21) arranged to attenuate noise transmission through the passage in at least one direction from the first to the second port. The noise attenuation device comprises at least one array (22, 23) of noise attenuation tubes disposed in the ventilation body. In one form, the noise attenuation device (21) include two arrays of attenuator tubes disposed on respective opposite sides of the passage (13). The tubes each have a mouth (27) that opens to the passage and a central axis that extends from the mouth in the direction of elongation of that tube. At least some of the tubes in the first array (20) oppose at least some of the tubes in the second array (23) with the central axes of the opposing tubes at the region of their mouths (27) being mutually inclined. |
