When the cut-off valve is closed from full open position, as the disc drops, the fluid causes pressure differential between the disc to prevent the disc from falling, and the resistance increases rapidly with the disc dropping. When the cut-off valve is closed, the pressure difference between the disc and the disc is equal to the working pressure of the medium. Then the force of the sealing force, so that the closing valve closed instantaneous operation force increased quickly. In the valve opening process, due to medium pressure or the pressure difference between the disc before and after the thrust is to help open the valve. It should be pointed out that the moment of opening the valve may exceed the torque of the shutoff valve, because at this time to overcome the larger friction. When the cut-off valve is opened, the opening height of the disc reaches the $number of the nominal diameter of the cut-off valve, the flow has reached the maximum, which indicates that the cut-off valve has reached the full open position, so the open position of the globe valve should be determined by the disc stroke. When the cut-off valve is closed and the case is opened again after Guan is similar to the mandatory sealed gate valve, the closing position of the cut-off valve should be determined by increasing the operating torque to the specified value.