| 摘要 |
[Problem] To attach a porous material to an installation section so as not to create a gap between the porous material and a duct main body. [Solution] An installation section (3) is provided on a planar section (6) of a peripheral wall section of a duct main body (2). An opening section (4) is provided to the installation section (3), and a porous material (5) is provided to the installation section (3) so as to cover the opening section (4) from the outside of the duct main body (2). If a cover (4) with a through-hole section (16) corresponding to the opening section (4) is attached to the installation section (3) so as to cover the porous material (5) provided to the installation section (3), a hook section (15) is fit into an attachment hole section (18), mutually joining the cover (4) and a stopper section (14) distributed so as to cover evenly in the direction along a circular shape of a partition wall section (14). The attachment hole section (18) may be provided on the duct main body (2) side, with the stopper section (14) and the hook section (15) provided on the cover (4) side, and the cover (4) may be joined to the partition wall section (14) by ultrasonic welding, vibration welding, thermal welding, an adhesive agent, or the like. |
