| 摘要 |
Apparatus for damping low frequency sound waves such as infrasound in centrifugal fansor pump apparatus. The apparatus is composed of one or more solely sound wave mediating channels (5, 10, 11) which connect the fans etc. housing (1) and conventional flow channel (3) or channels. The damping of the sound waves from the fan etc. is achieved through interference at the coupling locations between sound waves in the flow channels (3) and the solely sound wave transmitting channels (5, 10, 11). Because the extra channels (5, 10, 11) are solely sound wave transmitting suppression of disturbances in the flow and consequent instabilities with decreased efficiency and increased noise is achieved. The extra channels (5, 10, 11) can be flow channels of conventional type, but with one or more membranes (6, 7) or other sound wave transmitting organ mounted in the channels (5, 10, 11). Those membranes (6, 7) can advantageously be mounted in the openings of the extra channels (5, 10, 11) in order to be fitted to the conventional flow volumes form. |
