Smoke exhaust valve for ventilating duct

The utility model provides a ventilation pipeline smoke exhaust valve which comprises a shell, a rectangular box is arranged at the left end of the shell, a driving device is arranged at the left end of the rectangular box, the movable end of the driving device extends into the rectangular box, a plurality of rotating shafts are rotationally connected between the left wall and the right wall of the shell at equal intervals from top to bottom, and blades are arranged at the outer ends of the rotating shafts. The left end of the rotating shaft extends into the rectangular box, a pressing plate is slidably arranged on the inner wall of the shell, an opening penetrating through the front surface and the rear surface of the pressing plate is formed in the middle of the pressing plate, the pressing plate is located on the rear sides of the blades, magnetic blocks are installed at the four corner angles of the rear end of the pressing plate, and mounting plates are arranged on the rear sides of the magnetic blocks a