| 摘要 |
PURPOSE:To permit air stream to be effectively introduced into a volute chamber by varying the positions of a several pieces of tongue top edges out of a plurality of vanes installed onto an air guide and incresing the distance from an impeller in comparison with those of other tongue top edges and increasing the area of an inlet port. CONSTITUTION:Each tongue top edge 17a of some vanes 17 out of a plurality of vanes installed onto an air guide 15 is made shorter by a length l in comparison with other vanes and formed to a tongue top edge 17d, and the distance from an impeller 4 is made longer. With such constitution, the component of dynamic pressure which flows into the volute chamber 15a at the vane 17 part separated far from the impeller 4 can be secured sufficiently. Therefore, the tongue angle alpha for preventing surging can be secured sufficiently, though said increase of angle has not been executed by the reason that the area of the inlet part of the involute chamber 15a is made narrower, and the quantity of volute chambers 15a can be increased to improve the efficiency. |
