Internal thread gate valve, also called intercept, is one of the most widely used valves, belongs to the forced sealing valve, its closing principle is, rely on the valve bar pressure, so that the valve disc sealing surface and seat sealing surface closely fit, prevent the flow of media. It is divided into many kinds in different ways. The opening and closing parts of internal thread gate valve are plug shaped disc, the sealing surface is flat or conical, and the disc moves in a straight line along the center line of the fluid. Stem movement form, there are lifting rod type (stem lifting, handwheel not lifting), there are lifting rotary rod type (handwheel and stem rotating lifting together, nut in the valve body).
