| 摘要 |
PURPOSE:To improve a leakage loss around an impeller ever so better as well as to aim at improvements in blower efficiency, bt installing a labyrinth packing structural part in an outer circumferential end part of an air leakage passage in and around both front and rear shrouds of the impeller. CONSTITUTION:A labyrinth packing structural part (c) is installed in an outer circumferential end part of an air leakage passage around both front and rear shrouds 15 and 16 of an impeller 7 by means of annular fins 7a and 7b in the impeller 7, an annular groove 6a and a projected part 6b in a fan case 6 and an annular rib part 5a in a guide vane 5. In consequence, each clearance between the front shroud 15 and the fan case 6 as well as between the shroud 16 and a partition plate 12 of the guide vane 5 becomes large, and likewise althrough differential pressure between an outlet and an inlet of the impeller 7 is large enouth, an air leakage quantity can be restricted to as little as possible so that a leakage loss is reducible, thus improvements in blower efficiency is promotable.
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