Valves rely on the coordination of the valve body and disc to control the delivery of medium. After the valve is closed, the pressure difference between the inlet and outlet ends creates a pressure difference. At the moment of valve opening, the existence of the pressure difference can cause a huge instantaneous impact on the valve components and pipelines when the medium passes through the valve, leading to valve vibration and accompanied by noise. Vibration has an impact on the sealing performance, service life, and other equipment used for testing of valves and their connected pipelines. In some specific high-pressure working conditions, especially valves used in high-pressure pipeline systems, their vibration is particularly severe, which cannot meet the requirements of smooth operation, small vibration amplitude, and low noise.

The door buffer structure is composed of a central through hole and two symmetrically arranged bypass holes (not limited to two) on the valve disc that matches the valve body. The bypass hole is connected to the central through hole. A sealing seat is set at the center through-hole section from the sealing end face of the valve disc to the bypass hole, and a sealing disc is installed on the sealing seat to form a sealing component. When the sealing component is in the closed state, the bypass hole is not connected to the lower center through-hole. When the sealing component is in the open state, the bypass hole is connected to the lower center through-hole, connecting the inlet and outlet ends of the valve. The sealing flap is connected to one end of the transmission rod, and the other end of the transmission rod extends out of the center through hole to connect with the driving mechanism. The height of the limit groove is the distance that the sealing disc moves within the central through-hole of the valve disc, which should meet the requirements of connecting the central through-hole of the lower part of the valve disc with the bypass hole after the sealing component is opened.

When opening the valve, driven by the driving mechanism, the transmission rod rises, and the sealing disc connected to it rises accordingly. At this time, the valve disc does not move, and the sealing component is opened first. The medium will enter from the inlet end of the valve to the outlet end through the center through hole and bypass hole, and the pressure at the inlet and outlet ends of the valve will be balanced by a small amount of inflow medium. As the transmission rod continues to rise, under the limitation of the limit mechanism, the sealing disc and valve disc move up simultaneously, and the valve opens. On the contrary, when the transmission rod moves downwards, the sealing component is closed first, and as the transmission rod continues to move downwards, the valve closes.