Hydraulic valve The hydraulic valve is an automatic component operated by pressure oil. It is controlled by the pressure oil of the pressure regulating valve. It is usually used in combination with an electromagnetic pressure regulating valve. It can be used to remotely control the on/off of oil, gas and water pipeline systems of hydropower stations. Commonly used for clamping, control, lubrication and other oil circuits. There are direct-drive type and pilot-type type, and the pilot type is used.