| 摘要 |
PURPOSE:To improve static pressure and blow rate without making a blower large-sized by specifying the position of a fan casing closest to a fan surrounded by said casing and driven by a motor while specifying the ratio of pitch P to chord length l of fan. CONSTITUTION:A blower constituted from a fan 3 driven by a motor 1 and a fan casing 4 surrounding said fan 3 maintains pressure difference between inside and outside pressures of the casing 4 to even air flow while being provided with an intake orifice 5 having a rounded portion with small local pressure loss factor to restrain the local pressure loss and a blowing discharge port 6. Also, in the proximity of the discharge port 6 is formed a pressure branching tongue portion 7 for preventing discharged air from return. In this case, a position 8 on the fan casing 4 closest to the fan 3 is spaced from the pressure branching tongue portion 7. Also, the ratio (=p/l) of pitch P to chord length l of fan 3 is set to 0.75 or less.
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