Patent ID: 8584664

Claim:
A gas furnace system comprising: a heat exchanger; a flue coupled to the heat exchanger; a collector box connected between the heat exchanger and the flue; and an inducer fan assembly fluidly connected to the collector box, the inducer fan assembly including: a flow collector piece including motor support surface, a substantially toroidal collector, and a discharge region extending substantially tangentially from the collector, the collector forming a central recessed zone in the housing; a fan rotor rotatably mounted relative to the motor support surface, the fan rotor including a hub surface, a central region, and an outer circumferential edge, the fan rotor further including a plurality of blades extending from the hub surface, the plurality of blades extending from a leading edge at the central region across the hub surface to a trailing edge that extends beyond the outer circumferential edge, the plurality of blades including a first height at the central region and a second height at the circumferential edge, the second height being less than the first height, the first and second heights defining a blade tip revolved contour, wherein, the toroidal collector is arranged radially outward from and axially off-set from at least one of the hub surface of fan rotor and the motor support surface; and an inlet casing piece mounted to the flow collector piece, the inlet casing piece including a central opening that registers with the central region and an inlet casing contour that is substantially similar to the blade tip revolved contour of the fan rotor.