Generally called pilot valve. It is used to distribute the pilot oil. There are two solenoid valves on the upper surface. One is used to control the rotary motion of the excavator. There is a cylinder on the pilot valve set, which is filled with youdao nitrogen called accumulator, used to reduce the working device on the dead weight of the device after the engine is shut off (filled with proprietary nitrogen makes the hydraulic oil in the valve set has a certain pressure after the engine is shut off, can push the valve stem of the main control valve is the working device belongs to oil circuit guide). The last part is the oil feed to the pilot control handle.

Use model：922D