Patent ID: 11274678

Abstract:
A centrifugal blower includes a fan including a main plate having a disk-shape, and a plurality of blades, and a scroll casing configured to accommodate the fan. The scroll casing includes a discharge portion and a scroll portion including a side wall, a circumferential wall, and a tongue portion. The circumferential wall includes a curved circumferential wall and a flat circumferential wall. In comparison with a centrifugal blower including a standard circumferential wall having a logarithmic spiral shape in cross-section perpendicular to a rotational shaft of the fan, in the curved circumferential wall, at a first end being a boundary between the circumferential wall and the tongue portion and at a second end being a boundary between the circumferential wall and the discharge portion, a distance L1 between an axis of the rotational shaft and the circumferential wall is equal to a distance L2 between the axis of the rotational shaft and the standard circumferential wall.