Patent ID: 7311492

Claim:
A duct fan adapted to be arranged in a duct for transport of air between an upstream duct part and a downstream duct part, said fan comprising a housing ( 4 ) having substantially the shape of a rectangular parallelepiped and inside thereof a fan member in the form of an impeller ( 5 ) and a motor ( 6 ) for rotation thereof, a member ( 7 ) for connecting a first inlet side ( 8 ) of the housing to said upstream duct part for sucking air in therefrom and a member ( 9 ) for connecting a second outlet side ( 10 ) of the housing located opposite to said first side to said downstream duct part for exhausting air thereto, said impeller being a radial impeller having the axis of rotation substantially perpendicular to the direction of the main transport of air from said inlet to said outlet, wherein the outlet connecting member ( 9 ) is designed to define an airflow path tapering substantially conically in the outlet towards the end of that member adapted to adjoin to a said downstream duct part, and when viewing the housing ( 4 ) in the direction of the axis of rotation of the impeller, the center line of the opening ( 13 ) of the outlet connecting member ( 9 ) cone for connecting to said downstream duct part is substantially offset with respect to a center line of the housing extending from said first ( 8 ) to said second ( 10 ) housing side.