CENTRIFUGAL BLOWER

摘要

A centrifugal blower with reduced noise. The centrifugal blower has an impeller (2), a casing (3) receiving the impeller and forming a spiral flow path radially outside the impeller, and a drive device (4) for rotatingly driving the impeller about an axis (O). The impeller is constructed from a bottom plate (11), blades (12) arranged on the same circumference of the bottom plate, and a shroud (13) of a substantially annular plate shape, installed coaxial with the bottom plate with the blades positioned between the shroud and the bottom plate. The shroud is composed of an inclination section (16) approaching the bottom plate as it goes from the radially inside to the radially outside of the shroud, and a shroud side barrier wall (17) rising from a position more radially outside than the inclination section to the opposite side of the bottom plate. The casing is provided with a bell mouth (26) open at a position more on the radially inside than an inner peripheral edge of the shroud, and with a casing side barrier wall (27) projecting in the region between the inner peripheral edge of the shroud and the shroud side barrier wall.