Quick cut-off gate valve

The utility model belongs to the technical field of gate valves, and particularly relates to a quick cut-off gate valve which comprises a valve body, a valve rod is movably arranged in the valve body, a valve cover attached to the valve rod is installed on the upper side of the valve body, a first spring is installed at the bottom of the valve cover, and a supporting plate combined with the first spring is installed on the rod wall of the valve rod. A supporting frame is installed on the side wall of the valve body, a mounting groove is formed in the supporting frame, a second spring is installed in the mounting groove, a limiting plate is fixedly arranged on the side wall of the second spring, a limiting block is transversely arranged on the plate wall of the limiting plate, and when the valve body is closed, the limiting block can move downwards by pressing a valve rod. When the position of the limiting groove in the valve rod corresponds to the position of the limiting block on the supporting frame, the li