US Patent 9534610 Fan discharge duct having a scroll section

A fan assembly for generating an air flow within a room includes an impeller and a motor for driving the impeller to draw an air flow into the fan assembly, and a casing having an interior passage with a scroll section having a cross-sectional area that decreases from a scroll inlet section to a scroll outlet section. The scroll inlet section has an inlet port for receiving the air flow and the scroll outlet section has an outlet port for returning a first portion of the air flow to the scroll inlet section. The scroll section includes an air outlet for emitting a second portion of the air flow from the casing. The casing defines a bore through which air from outside the fan assembly is drawn by the air emitted from the air outlet.