Axial flow fan.

摘要

An axial flow fan comprising a rotor (10) having a hub (3) provided with a plurality of fan blades (4); a casing (1) within which the rotor (10) is mounted; and a flow channel (11) which is formed between the casing (1) and the rotor (10) and which extends from an inlet port (6) of the fan to an outlet port (7) thereof, characterised in that the diameter of the flow channel (11), at a position adjacent the outlet port (7), is at a minimum value.