FORCED-DRAFT PRE-MIX BURNER DEVICE FOR A VEHICLE HEATER

The invention relates to a forced-draft pre-mix burner device (16) comprising: i) a housing (18) that conveys air from an upstream cool air inlet (24) to a downstream warm air outlet (26); ii) a heat exchanger (40) that warms the air prior to discharge via the warm air outlet (26); iii) a gas burner (44) that burns an air-gas mixture to thereby warm the heat exchanger (40); and iv) a fan (28) that mixes the air-gas mixture and forces the air-gas mixture into the gas burner (44). The fan (28) comprises a plurality of blades (34) that rotate around an axis of rotation (35). The fan (28) further comprising an end cap (72) having an end wall (73) that faces the plurality of blades (34), an air-gas mixture inlet (88) through which the air-gas mixture is conveyed to the plurality of blades (34), and an air-gas mixture outlet (90) through which the air-gas mixture is conveyed to the gas burner (44). The air-gas mixture inlet (88) is connected to the air-gas mixture outlet (90) via a channel (98) formed in the end wall (73), wherein the channel (98) forms a depression in the end cap (72) that gradually becomes shallower from the air-gas mixture inlet (88) to the air-gas mixture outlet (90) along its length from the air-gas mixture inlet (88) to the air-gas mixture outlet (90), thus gradually forcing the air-gas mixture axially into an interior (69) and into the compartments formed between the adjacent blades (70).