Patent ID: 9194398
Filing Date: 2015-11-24
Classification: F04D

Abstract:
1. A centrifugal fan comprising: a casing comprising an upper casing which has an air suction opening; a lower casing; a plurality of support members disposed between the lower casing and the upper casing, wherein air discharge openings are provided between the support members; an impeller which is disposed in the casing between the upper casing and the lower casing, wherein the impeller comprises an annular upper shroud which is provided on an upper casing side, a lower shroud, and a plurality of blades which are arranged along a circumference direction between the annular upper shroud and the lower shroud; and a fan motor configured to rotate the impeller, wherein an upper surface of the upper shroud facing the upper casing comprises a curved surface, wherein the upper casing comprises an upper surface and a lower surface facing the upper shroud, the lower surface of the upper casing having a shape with a curvature which is close to that of the upper surface of the upper shroud, wherein a plurality of recesses are provided on the upper surface of the upper casing, and a depth of each recess becomes gradually deeper from an inside of the upper casing toward an outside of the upper casing, and wherein a plurality of ribs are radially provided around the air suction opening and between the adjacent recesses.