Blauberg duct fans with backward curved aerodynamic impeller blades designed as freewheels fans that could be installed at any directions by extremely compact size, and optimized output air performance without scroll housing necessary to have.

（1）Centrifugal Fans, Forward Curved，Technical Features Overview Higher Air Pressure with Lower Noise and Power Consumption Blauberg centrifugal fans with forward curved impeller designed as freewheels fans, with and without scroll housing optional. The fans could be installed at any directions by ex