Axial flow fan and air valve, cooling tower and air cooler thereof

The utility model discloses an air valve for an axial flow fan, an axial flow fan with the air valve and a cooling tower with the axial flow fan or an air cooler, wherein the air valve for the axial flow fan comprises a valve body and a plurality of blades, each blade comprises a blade shaft and a main blade, the inner side of the main blade is fixed to the blade shaft, the valve body comprises an outer cylinder and a center seat which are fixed relatively, the center seat is arranged in the outer cylinder, the outer end and the inner end of the blade shaft are rotatably arranged on the outer cylinder and the center seat, and the blades are distributed on the periphery of the center seats in a radial form. The blades can be matched with pressure distribution of an air outlet of the axial flow fan in the disclosed air valve for the axial flow fan, a blade distribution area corresponds to a positive pressure exhaust area of the air outlet, and the opening angle of each blade can match with pressure of the area