Patent ID: 8057161

Claim:
A fan ( 44 ) in the form of an axial or diagonal fan, comprising: a fan housing formed with an air inlet opening and an air outlet opening, and having an outflow baffle ( 30 ) provided adjacent the air outlet opening, which baffle ( 30 ) includes a plurality of stationary air-guiding vanes ( 33 - 40 ) shaped to counteract helical motion of air flowing out of the fan ( 44 ) and to at least partially convert said helical motion, of the air flowing out of the fan ( 44 ), into static pressure, said air-guiding vanes ( 33 - 40 ) defining at least one air passage opening, wherein said baffle ( 30 ), on an outlet side of this air passage opening, is provided with at least one non-return flap ( 72 , 74 , 76 , 78 ), pivotable between a fully open orientation, aligned with an axis of said fan, and a closed orientation, substantially co-planar with said air outlet opening, in which said flap at least partially closes the air passage opening, and wherein at least one elastic element ( 80 , 92 ) couples together said baffle ( 30 ) and said flap, and acts on this non-return flap in a direction toward said closed orientation thereof.