| 摘要 |
PROBLEM TO BE SOLVED: To reduce blast sound by setting an outlet angle of each blade of an impeller into a specified range, and setting the inner and outer diameter ratio of the impeller into a specific range in a multiblade blower applied to a ventilating system path high in the passage resistance of a duct system of a duct ventilating device or the like. SOLUTION: In a multiblade blower applied to a ventilating system path high in the passage resistance of a duct system, an outlet angle β2 in an air blowoff part of each blade 2a of an impeller 2 is set into a range of 120 deg.<β2<130 deg., and the ratio D1/D2 of the inner diameter D1 of the impeller 2 to the outer diameter D2 is set into a range of 0.6<D1/D2<0.7. In the case of forming the impeller 2 of the multiblade blower by a combination of such an outlet angle β2 of the blade 2a of the impeller and such an inner and outer diameter ratio D1/D2 of impeller 2, the multiblade blower low in blast sound and high in blast efficiency can be compactly realized without causing an unstable phenomenon due to separation in a small flow area even in the case of being applied to a duct ventilating device or the like large in the passage resistance of the duct system. |
