| 摘要 |
<p>The door has five intermediate layers (4, 5a-5c, 6), where one of the intermediate layers is a sound-absorbing medium i.e. mineral wool material, that is arranged between two outer layers i.e. door forming sheet metals (1, 2). The two outer layers are arranged opposite to each other and formed by external layers of different thickness. A set of layers comprises a bitumen material that is attached at the outer layers, and another set of layers includes a gypsum cardboard material. The sound-absorbing medium is inserted between the latter set of layers in an uncompressed manner.</p> |
