Air valve for heating and ventilation system

The utility model discloses an air valve for a heating and ventilation system, which comprises a main valve body, a dustproof shell arranged on the periphery of the main valve body, a rectangular fixing structure of a containing space formed between the main valve body and the dustproof shell, and at least two blade components distributed in the main valve body at equal intervals. The two ends of the blade assembly are rotationally installed on the valve body through bearing sleeves. The worm and gear transmission mechanism is arranged in the containing space and comprises a worm gear and a worm, the worm gear is arranged on the bearing sleeve at one end of the blade assembly in a sleeving mode, the worm is meshed with teeth of the worm gear, one end of the worm is installed on the main body through a bearing seat, and a motor for driving the worm to rotate is arranged at the other end of the worm; by arranging the multiple blades, the adjustable ratio of the blades is increased, and therefore the circulation