Patent ID: 7462014

Claim:
An axial flow fan comprising: a rotor; a frame; a base disposed inside the frame for supporting the rotor; and a plurality of stationary blade units mounted between the frame and the base, wherein each of the stationary blade units at least includes a first blade and a second blade, and a segment space between the first blade and the second blade maintains a laminar flow of the fluid passing over a surface region of the first blade and the second blade, wherein the second blade is configured in front of an upper surface of the first blade in a direction perpendicular to a flow direction of the fluid; wherein the first blade has a first leading edge and a first rear edge, the second has a second leading edge and a second rear edge, the second leading edge of the second blade is positioned adjacent to the first rear edge of the first blade, and the second blade introduces the fluid from the first blade and reforms a boundary layer of the fluid passed through the upper surface of the first blade so as to prevent a separation effect on the upper surface of the first blade; wherein the second blade is located in an outer portion of the laminar flow with respect to a center of curvature of the laminar flow.