Patent ID: 9387298
Filing Date: 2016-07-12
CPC Classification: A61M,F04D

Claim Text:
1. A fan unit which in use forms part of a gases supply unit suitable for use as part of a system for providing heated gases to a user, said fan unit comprising: a casing defining a diffuser, a volute, an inlet and an outlet, said volute further defined by a channel that encircles said diffuser, an impeller located within said casing and adapted for connection to a motor, said impeller further having an inducer adapted to receive a gases stream from said casing inlet, said diffuser located at least partially annular to said impeller, said impeller further having an exducer adapted to expel gases to said diffuser and said volute, a recirculation passage providing a gases flow path between an area proximate said exducer and an area proximate said inducer, wherein a lower surface of said diffuser and an inner wall of said volute define an angular transition of more than 270 degrees, wherein said lower surface of the diffuser is sloped up to 6 degrees from a plane tangential to the axis of impeller rotation.