The hydraulic valve is an automation component operated by pressure oil. It is controlled by the pressure oil of the pressure distribution valve. It is usually used in combination with the electromagnetic pressure distribution valve. It can be used to remotely control the on and off of the oil, gas, and water pipeline systems of hydropower stations. Commonly used for clamping, control, lubrication and other oil circuits. There are direct-acting type and pilot type, and the pilot type is mostly used. The components used to control the pressure, flow and direction of liquid in hydraulic transmission. The one that controls pressure is called pressure control valve, the one that controls flow is called flow control valve, and the one that controls on, off and flow is called directional control valve.