| 摘要 |
PURPOSE:To provide a sound deadening duct with a simplified structure and demonstrating a remarkable sound deadening effect. CONSTITUTION:A sound deadening duct 1 comprises a duct body constituted with punching metal with a 25% opening rate and including an entire wall surface made a porous sound transparent wall 11, and an airtight sheet 20 laminated on the porous sound transparent wall 11 so as to sealing the same in an airtight manner. The airtight sheet 20 is of an incombustible sound transparent one yielded by molding inorganic fibers for example with a phenol binder in a mat configuration, and covering it with an inorganic cross. Hereby, any noise in the sound deadening duct 1 passes through the porous sound transparent wall 11 and the airtight sheet 20 and is actively discharged to the outside of the duct 1, whereby the sound deadening duct 1 reduces the sound to the utmost and fan air is prevented by the airtight sheet 20 from being discharged. |
