| 摘要 |
An inner shell having aligned first and second expansion chambers is spacedly disposed in an outer shell in a manner to define therebetween four isolated chambers upstreamly positioned two of which surround the first expansion chamber and downstreamly positioned two of which surround the second expansion chamber. The first expansion chamber is connected through respective flanged openings to the upstreamly positioned isolated chambers to allow these chambers to show a sound damping effect. The upstream and downstream portions of the second expansion chamber are connected through respective groups of perforations to the downstreamly positioned isolated chambers to allow these chambers to show a sound damping effect.
|
