| 摘要 |
PURPOSE:To increase the quantity of blast by providing an air passage in between the inner periphery of the blades of a centrifugal impeller and the outer periphery of an axial flow impeller, and forcedly sending part of an air stream which flows inside said centrifugal impeller, from an upper course side to a lower course side via said axial flow impeller. CONSTITUTION:An axial flow impeller 29 is provided inside a centrifugal impeller 28 and, by rotating both of the impellers, an air stream fed from an air feed port 36 of a casing 21 is made flow to discharge ports 22 and 23 via an air passage 31, etc. provided in between the inner periphery of the blades 30 of the centrifugal impeller 28 and the outer periphery of the axial flow impeller 29, due to the centrifugal force of the centrifugal impeller 28. And, part of the air stream flowing inside the centrifugal impeller 28 is forcedly sent from an upper course side to a lower course side via the axial flow impeller 29 and, then, forms flows directed to the discharge ports 22 and 23. Accordingly, the axial lengths of the impellers can be increased without lowering the efficiency of the impellers, enabling the quantity of blast to be increased.
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