Patent ID: 7883312

Claim:
A centrifugal blower, comprising: an impeller; a casing that houses said impeller and forms a spiral flow passage that surrounds a circumference of said impeller; and a driving device that rotates said impeller about an axis, wherein said impeller has: a disk shaped bottom plate that is rotated about said axis by said driving device; a plurality of blades provided so as to project in said axial direction on a same circumference of said bottom plate; and a substantially annular plate shape shroud that has said blades interposed between it and said bottom plate, and that is disposed concentric with said bottom plate, and that connects end sections of the respective blades, said shroud has: an inclined section in which radially the more outside a portion thereof is, the closer the portion is to said bottom plate; and a shroud side barrier provided in a radially outer side of said inclined section to extend away from said bottom plate, said casing has: a bell-mouth that opposes an inner circumference of said shroud; and a casing side barrier provided on a radially outer side of said bell-mouth to extend into a gap between said inclined section and said shroud side barrier, and the inclined section, the shroud side barrier, the bell-mouth and the casing side barrier overlap with each other in a radial direction, wherein said casing has a wind shielding plate provided on a part of said bell-mouth in the vicinity of a start point of said spiral flow passage to rise radially inward and away from said bottom plate.