Patent ID: 6984111

Claim:
A multiblade blower, comprising an impeller having a plurality of blades placed circumferentially, and taking in air from a side of an inner diameter end portion of each of the blades and discharging the air from a side of an outer diameter end portion of each of the blades by rotation of the impeller, wherein two or more of blade groups, in each of which said blades are placed in a ring shape, are placed, such that the blades of an outer blade group are between and extend beyond at least one inner blade group at least in a radial direction, and each blade of the outermost blade group is placed inside air flows passing between blades of the at least one inner blade group; wherein said at least one inner blade group comprises a plurality of main blades and said outer blade group comprises a plurality of auxiliary blades, and an inner diameter end portion of each of the auxiliary blades is placed between a pressure surface of an outer diameter end portion of one of the adjacent main blades and a suction surface of the other main blade and wherein a thickness dimension measured substantially perpendicular to the chord of said main blade is larger than a thickness dimension measured substantially perpendicular to the chord of said auxiliary blade.