Patent ID: 9644631
Date: 2017-05-09
CPC Classifications: F04D,F05D

Claim:
1. A multi-blade centrifugal fan comprising: an impeller having numerous blades and provided in a freely rotatable manner in a scroll casing formed in a spiral shape with a tongue portion serving as its starting point, an axially expanded portion provided in the scroll casing that forms an air channel that is expanded in a rotation axis direction at a radially outer side of an annular flange portion that supports the impeller at the bottom surface of the scroll casing; and a vortex control plate provided near the tongue portion in a region of an outlet, the region of the outlet being provided on an air flow downstream side of a spiral-end portion of the the scroll casing and being provided in the axially expanded portion, and that is provided over an area from an air flow upstream side of the tongue portion in the region of the outlet to an inner circumferential side surface of the axially expanded portion in the region of the outlet, the height of the vortex control plate in a rotation-axis direction of the impeller gradually increased from an air flow upstream side to an air flow downstream side.