The hydraulic control valve is a hydraulic pressure control valve. It consists of a main valve and its attached conduit, pilot valve, needle valve, ball valve and pressure gauge.

Type of hydraulic control valve: according to the different use purpose, function and place can be changed into remote control floating ball valve, pressure relief valve, slow closing check valve, flow control valve, pressure relief valve, hydraulic electric control valve, water pump control valve and so on. According to the structure, it can be divided into two types: diaphragm type and piston type.

The working principle of the diaphragm type and the piston type two valves of the hydraulic control valve is the same, which is the power of the downstream pressure difference Delta P, which is controlled by the guide valve to make the diaphragm (piston) hydraulic differential operation completely automatically adjusted by hydraulic, so that the main valve disc is completely open or completely closed or in the state of adjustment. When the pressure water in the control room above the diaphragm (piston) is discharged into the atmosphere or downstream low pressure area, the pressure value under the valve plate bottom and below the diaphragm is greater than the above pressure value, so the main valve disc is pushed to the completely open position; when the diaphragm (piston) is entered, the pressure water in the control room can not be discharged to large When the gas or downstream low pressure area, the pressure value above the diaphragm (piston) is greater than the pressure value below, so the main valve disc will be pressed to the completely closed position; when the pressure value in the control room above the diaphragm (piston) is in the middle of the inlet pressure and the outlet pressure, the main valve disc is in the adjustment state and its adjustment is in the adjustment state. The location of the joint depends on the combined control function of the needle valve and the adjustable pilot valve in the catheter system. The adjustable guide valve can open or close its own small valve port through the pressure of the downstream outlet and change with it, so as to change the pressure value of the control room above the diaphragm (piston) and control the regulating position of the valve disc.