Patent ID: 9192735
Filing Date: 2015-11-24
Classification: A61M,F04D

Abstract:
1. A fan unit that in use forms part of a gases supply unit suitable for use as part of a system for providing heated humidified gases to a user, said fan unit comprising: a casing having an inlet aperture and an outlet passage, said outlet passage having an exit aperture, and at least one vent hole independent of said exit aperture and arranged at an angle to a path of a gases stream through said outlet passage; and a fan located inside said casing and adapted for connection to a motor to drive rotation of said fan in use so that in use said fan draws gases into said casing via said inlet aperture and forces said gases out of said casing via said outlet passage as said gases stream, said outlet passage and said at least one vent hole configured so that, if said outlet of said outlet passage is substantially blocked, a flow in use through said at least one vent hole matches a flow through said outlet passage at which an onset of surge would occur in a substantially blocked outlet passage without a vent hole or holes.