Patent ID: 6964555

Claim:
A centrifugal blower comprising: a centrifugal fan including a boss portion, a plurality of blades arranged on a periphery of the boss portion in parallel to an axial direction, and a shroud connecting to ends of the blades, wherein the shroud defines a fan inlet port through which air is sucked in the centrifugal fan and the blades define discharging ports through which air is discharged in a radially outward direction; a motor connected to the boss portion for driving the centrifugal fan; a scroll casing including a first scroll wall defining a casing suction port, a second scroll wall opposed to the first scroll wall and holding the motor, and a peripheral wall connecting the first scroll wall and the second scroll wall, wherein the scroll casing houses the centrifugal fan such that the fan inlet port is adjacent to the casing suction port and defines a blowing passage space between the discharging ports and the peripheral wall and into which air discharged from the centrifugal fan flows, and at least one of the first scroll wall and the second scroll wall protrudes in the axial direction at a position corresponding to the blowing passage space so that the blowing passage space and a space provided in the protruded portion define a scroll air passage; and a directing member disposed at a position that a primary flow discharging from the centrifugal fan and a secondary flow that is created in the scroll air passage merge with each other so that one of the primary air flow and the secondary air flow is directed to be in parallel with the other; wherein the directing member is provided by a fin in a form of annular plate, and the fin is disposed in an inside of the protruded portion.