| 摘要 |
A blower comprising an annular wall (2) formed to be spaced from blade tips of a fan (1), the annular wall having slits (6) formed at a portion opposed to the blade tips to establish communication between inner and outer peripheral portions of the annular wall, so that air is sucked into the inner peripheral portion of the annular wall through the slits as the fan rotates, characterized in that the width w of a gap of the slit is changed in radial and circumferential directions thereof, whereby the quantity of air flowing into the inner peripheral portion of the annular wall through the slits is made substantially equal over the entire circumference. By this configuration, leakage vortexes flowing from the pressure side to the suction side at the blade tips are restrained, and the P-Q characteristics are improved. At the same time, noise produced in the annular wall having slits can be restrained, so that a low-noise blower can be realized.
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