| 摘要 |
PROBLEM TO BE SOLVED: To provide a blast air stirring device capable of blowing air in the wide range at a low cost and a ventilation system for a building using the blast air stirring device. SOLUTION: This blast air stirring device is provided with one motor, a fan, and an annular fan casing arranged around the fan. The fan casing is partitioned and divided in the rotational axial direction of the fan into plural stages to form plural stages of annular casing parts, two to six volute air passages are circumferentially formed on respective casing parts at approximately equal distances, and the circumferential forming positions of air inflow ports and discharge ports of the volute air passages are displaced at the casing parts of respective stages.
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