| 摘要 |
<p>984,817. Silencing gaseous currents. WOODS OF COLCHESTER Ltd. March 13, 1961 [March 11, 1960], No. 8703/60. Heading FIB. A silencing device, formed as a Venturi contraction in sound absorbing material, is located immediately downstream of an electric motor driven axial flow impellor 12, Fig. I operating in a duct 11. In another embodiment an axial body 23, Fig. 2, may form the venturi contraction and one or more annular guide vanes 29 may be provided in the diverging section. In modifications an axial body and annular guide vanes may be provided in a lining as in Fig. 1 and surface 25 may be perforated. In a further embodiment an axial body 34 forms the venturi contraction with a duct section of greater internal diameter than duct section 11.</p> |
