| 摘要 |
PROBLEM TO BE SOLVED: To average air stream, discharged out of an impeller wheel, from the inner peripheral part to the outer peripheral part of the impeller wheel without generating the collision of air streams in an orifice ring and without biasing to the outer peripheral part of the impeller wheel by a method wherein the discharging part of orifice ring is expanded suddenly toward the outer peripheral direction of the impeller wheel. SOLUTION: An orifice ring 16 is fixed at the tip end of a vane 17 for the outer peripheral part of an impeller wheel 15 while the orifice ring 16 is provided with the shape of bell mouth in the rotating direction of the impeller wheel 15 from a contacting part between the tip end of the vane at the outer peripheral part of the impeller wheel 15 and the orifice ring 16 in a space between the vanes 17 of the impeller wheel 15. On the other hand, a clearance exists between the vane 17 and the orifice ring 16 in a direction opposite to the rotating direction of the impeller wheel 15 while the suction part 16a of the orifice ring 16 is contracted gradually in the inner peripheral direction of the impeller wheel 15 from the suction side of the suction part 16a of the orifice ring 16 toward the discharging side of the same to expand the discharging part 16b of the orifice ring 16 suddenly toward the outer peripheral direction of the impeller wheel 15. |
