1, the concept of the hydraulic control valve: hydraulic control valve is a pressure control valve, which consists of a main valve and attached to the catheter, the pilot valve, needle valve, ball valve and pressure gauge.

    Category 2, the hydraulic control valve: according to the different purpose, function and location can be turned into a remote control float valve, relief valve, relief valve closed, the flow control valve, relief valve, hydraulic electric control valve, pump control valve. According to the structure can be divided into two types of diaphragm and piston.

     3 working principle, hydraulic control valve diaphragm and piston type two kinds of valves, are more downstream pressure difference △ P powered, controlled by the pilot valve, the diaphragm (piston) hydraulic differential operation, completely by the hydraulic automatic control, so that the main valve disc valve fully open or fully closed or in the adjustment of state. When entering the diaphragm (piston) pressure above the control room of water is discharged into the atmosphere or downstream of a low pressure area, function below the valve plate at the bottom and diaphragm pressure value is greater than the upper pressure, so will the main valve disc is pushed to the fully open position; when entering the diaphragm (piston) on pressure water can not control the indoor exhaust into the atmosphere or downstream of a low pressure area, role in the diaphragm (piston) above the pressure value is greater than the bottom pressure value,

     so it will take the main valve disc pressure to full closed position; when the diaphragm (piston) above the control room pressure value in the middle entrance pressure and outlet pressure, the main valve the valve plate is in the adjustment state, needle valve regulating position depends on in the ductal system and joint control adjustable guide valve. Adjustable valve outlet pressure through the downstream and changes it to open with a small valve or Guan Xiaoqi's own mouth, thus changing the diaphragm (piston) pressure above the control room, control the regulation side valve disc position.