VENTILATEUR

摘要

The fan comprises an impeller 2 and a system for imparting prerotation swirl to the air flow entering the impeller. The swirl system includes a bypass conduit 6 and an adjustable baffle 9. Normally the baffle blocks the inlet 7 of the conduit 6 so that the entire airflow passes through the inlet box 5 and inlet cone 4 to the impeller. When the baffle is swung away from the inlet 7, the air flow is divided into two streams 10, 11, the stream 11 being swirled due to the tangential direction in which the air is supplied from the conduit 6 to the inlet cone 4.