| 摘要 |
PURPOSE:To get a sound absorbing and sound reducing amount more than a theoretical value by a method wherein a honeycomb structure is disposed at an inner circumferential surface of a cylindrical casing, some porous materials are disposed at an inner side of the honeycomb structure and then the spaces defined by the porous materials are employed as a flow passage. CONSTITUTION:A honeycomb structure 2 having a predetermined thickness is disposed on the entire inner circumferential surface of a casing 1. Some porous material 3 having a predetermined thickness is disposed at the inner side of the honeycomb structure 2, and then honeycomb structure 2 is held between the casing 1 and the porous material 3. A spacing defined by the porous materiels 3 forms a flow passage 4 for flowing gas. Fixing of the honeycomb structure 2 and the porous material 3 is carried out such that between the casing 1 and the honeycomb structure 2 and between the honeycomb structure 2 and the porous material 3 may be adhered or fixed to each other. A rectangular cylindrical porous material 3 is forcedly fitted and the honeycomb structure 2 may be held by the casing 1 and the porous material 3. The porous material 3 has as its material, metal or ceramics and the like, some communication holes are provided and then a substantial rigid member is formed. The honeycomb structure 2 is made of metal, synthetic resin and pulp paper of the like. |
