| 摘要 |
<p>The present invention provides a ventilating apparatus for installation on or in the ventilating slot of a wall or the frame of a window or door, comprising a housing having a back wall accommodating an air intake, side walls insulated from the back wall by a heat insulating element interposed therebetween and an air exhaust at the front of the housing provided with a cover, and sound absorbant material in said housing through which is formed an air duct extending n a meandering path from said air intake to said air exhaust, the walls of said duct being arranged such that opposed surfaces thereof are generally of sound absorbant material and sound conductive material respectively.</p> |
