Abstract: A vortex blower having an impeller provided with an annular recess laterally opening around an axis of rotation, a casing disposed so as to face the impeller and cover a radially outer portion of the impeller, an arcuate recess formed around the rotation axis in a portion of the casing which extends between a suction port and a discharge port and opposes to the annular recess, and a plurality of blades provided in the annular recess to divide the recess into a plurality of circumferentially arranged pockets, each having a radially outer end extending towards the arcuate recess beyond the annular recess. The vortex blower having such a construction can operate safely even when drawing air in which dust is suspended.

Abstract: A vortex blower comprises a motor and an impeller directly connected to one end of a motor shaft and housed in an impeller housing. A part of the impeller housing is made of aluminium or aluminium-based alloy and includes an integral portion which serves as that end wall of the motor which is adjacent to the impeller. The end wall is provided with a radially extending first thrust surface for engagement with one end face of an outer race of a bearing which journals the motor shaft. A bearing retainer of a metal having a wear-resistant property higher than those of aluminium and the aluminium-based alloy is provided with an axially extending cylindrical surface for engagement with the outer peripheral surface of the outer bearing race and a radially extending second thrust surface for engagement with the other end face of the outer bearing race.