| 摘要 |
<p>An improved method for attenuating sound and a sound attenuating device for use in a gas transportation duct, said device comprising a core of acoustically absorptive material (5) substantially enclosed within an impervious film (6) to prevent direct contact between the acoustically absorptive material and gas flowing through said gas transportation duct, wherein said enclosed absorptive material is maintained in position between at least two perforated facing plates (3) and further wherein there is provided between the perforated facing and the impervious film spacing means (7) to prevent contact between the film and the perforated facing and blocking means to impede the internal flow of air between the film and the perforated facing.</p> |
