TURBO FAN, BLOWING DEVICE USING TURBO FAN AND AIR CONDITIONER

摘要

PROBLEM TO BE SOLVED: To increase pressure, heighten blowing efficiency and lower noises for a turbo fan or to save energy and lower noises for an air conditioner. SOLUTION: This turbo fan arranges a shroud, a hub and backward curved blades which face reversely to plural rotational directions. In a height direction of an impeller, an impeller rotational direction side surface of the blade has a smooth protruding shape in a rotational direction from an impeller internal circumferential side to the vicinity of the center and a smooth recessed shape in the rotational direction from the vicinity of the center to the impeller internal circumferential side. An impeller rotational direction rear surface is curved such that it has a smooth recessed shape in the rotational direction from at least the vicinity of the center to an impeller outer circumferential side tip of the blades. This turbo fan has a wing-shaped blade section whereof blade thickness gradually increases from an impeller internal circumferential side tip and then gradually decreases to an outer circumferential side tip.