To stabilize the position of a re-circulating vortex and reduce the size of the same by a method wherein the opposing surface of a stabilizer is provided with a projected part, projected toward an impeller, at the intermedi ate position in the widthwise direction of the same.
A stabilizer 20 is provided with an opposing surface 21, opposed to the outer periphery of an impeller 3 with a space, while the opposing surface 21 is provided with a projected part 22, projected toward the impeller 3, at an intermediate position in the widthwise direction of the opposing surface 21. In this case, upon rotating the impeller 3, a re-circulating vortex 6, formed in conjunction with the stabilizer 20, is formed stably at a predetermined position by the effect of the projected part 22 and the size of the vortex is also reduced. A distance δ between the tip end 23 of the opposing surface 21 and the outer periphery of the impeller 3 can be provided sufficiently whereby a suction area can be retained so as to be large enough. Accordingly, not only the amount of suction air can be secured sufficiently but also the flow rate distribution 9 of air, passed through a heat exchanger 5 arranged at the upstream of a suction side, is unified.
NOBORI SHIGEYUKI
ITO KENJI
SHIMOJI MASAHITO
