Non-counterweight top bleeding valve used in blast furnace ironmaking, including valve body, valve cover and driving device. The valve body consists of a seat, a middle shell and a lower shell. The opening and closing device of the bonnet is composed of large, small rotating arm and its support and the connecting plate between them. The bonnet is connected with the large rotating arm hinge, the large rotating arm and its large support hinge is connected, the small rotating arm and its small support are connected, and the large rotating arm and the small rotating arm are connected with the connecting plate hinge. When the two pin shaft holes connected by the connecting plate and the large and small rotating arms are in a vertical position, the opening and closing device is self-locked and the valve cover is closed. When the driving device pulls the small rotating arm, the two pin shaft holes connected by the connecting plate and the large and small rotating arms deviate from the dead point position, and the small rotating arm drives the connecting plate, thus pulling the large rotating arm swinging and the valve cover being opened. The non-weight self-locking release valve makes use of the position relationship between the rotating arm and the connecting plate to realize the rapid opening of the valve cover, ingenious structure, light weight, small starting power, safety, economy and prolongation of service life.
Gas bleeding valve