Hydraulic control valves can be divided into two types according to their structure: diaphragm type and piston type. They operate on the same principle, using the pressure difference between upstream and downstream, denoted as △P, as their power source. Controlled by a guide valve, they enable differential hydraulic operations of the diaphragm (or piston), fully regulated automatically by hydraulic means, thus allowing the main valve disc to fully open, fully close, or be in a regulating state. When the pressure water entering the upper control chamber of the diaphragm (or piston) is discharged into the atmosphere or a downstream low-pressure area, the pressure values acting on the bottom of the valve disc and below the diaphragm are greater than those above, thus pushing the main valve disc to a fully open position. If the pressure water cannot be discharged into the atmosphere or downstream low-pressure area, the pressure value above the diaphragm (or piston) will be greater than the one below, pushing the main valve disc to a fully closed position. When the pressure value in the upper control chamber of the diaphragm (or piston) is between the inlet and outlet pressures, the main valve disc is in a regulating state, with its regulating position determined by the combined control action of the needle valve and adjustable guide valve in the conduit system. Zhongmei zmjt063
An adjustable guide valve can adjust its own small valve opening by responding to the downstream outlet pressure and its changes, thereby altering the pressure value in the control chamber above the diaphragm (piston), controlling the adjustment position of the valve disk.
Hydraulic control valves, categorized by their structure and control methods, include: remote-controlled float ball valves (for controlling liquid level), pressure-reducing valves, slow-closing check valves, flow control valves, pressure/relief valves, hydraulic/electric control valves, pump control valves, differential bypass valves, emergency shutdown valves, and more.