Patent ID: 7207774

Claim:
A centrifugal fan comprising: a scroll casing that has an almost cylindrical shape including a first base wall, a second base wall, and a side circumferential wall, an air inlet that is opened in an axial direction being formed on a center portion of said first base wall, and an exhaust port that is opened in a circumferential direction being formed on one position of said side circumferential wall; a motor that is attached to a center portion of said second base wall at the inside of said casing so that a rotating shaft of said motor is perpendicular to said second base wall; a circuit board on which a control circuit for driving said motor is contained, said circuit board being supported at the position between said motor and said second base wall; and an impeller that is fixed to said rotating shaft, said impeller having many blades along the outer region thereof, wherein a cylindrical partition is formed on the inside of said second base wall over the entire circumference to jut toward said impeller, said partition consists of a high partition that has relatively large height in at least a region close to said exhaust port and a low partition that has relatively small height in the other region.