What is the control method of the pressure control valve?

Pressure control valves come in two types: hydraulic and pneumatic, but their principles are almost the same. Here is an explanation of the hydraulic valve structure: 1 - adjusting screw; 2 - valve body; 3 - pressure regulating spring; 4 - deflection disc; 5 - cone valve; 6 - damping piston. Function: The damping piston serves two functions. Firstly, it provides damping when the cone valve opens or closes, enhancing the pressure regulating stability of the valve. Secondly, it guides the cone valve, improving the sealing performance of the valve.

  The function of the drift disc: The drift disc is equipped with an annular groove, which is used to change the direction of fluid flow at the outlet of the cone valve. As a result, the drift disc experiences a hydraulic force, which acts in the opposite direction to the spring force and increases with the increase in overflow volume. When the overflow volume increases, the opening of the cone valve enlarges, causing an increase in spring force. However, since the hydraulic force also increases simultaneously, the structure cancels out the increase in spring force. Therefore, the inlet pressure of this valve is not affected by changes in flow rate, and its p-Q characteristic curve is relatively ideal, with good opening and closing characteristics, which is conducive to improving the rated flow rate of the valve.

    Application: 1) Functioning as a safety valve (preventing overload of the hydraulic system) When the overflow valve functions as a safety valve, it is to limit the maximum pressure of the hydraulic system to ensure system safety. Under normal operating conditions of the system, the valve is closed and does not overflow, and the working pressure of the system is determined by the external load. When the system pressure reaches the set pressure of the valve, the valve opens to overflow, and at this time, the system pressure is determined by the set pressure of the overflow valve.

    2) Functioning as an overflow valve (maintaining constant pressure in the hydraulic system) In a throttling speed control system, the overflow valve is normally open during normal operation, and it maintains the pressure in the hydraulic system basically constant by overflowing excess oil back to the oil tank.

    3) To unload the hydraulic system, the remote control port of the pilot-operated relief valve is connected to the oil tank, allowing the system to be unloaded using the relief valve. The DBW type pilot-operated electromagnetic relief valve can achieve system unloading using its own electromagnetic directional valve, while other pilot-operated relief valves require the addition of a directional valve on the remote control port to achieve system unloading.

    4) Remote pressure regulation: Connecting a remote pressure regulating valve to the remote control port of the pilot-operated relief valve enables remote pressure regulation.

In addition, the overflow valve can also be used as a back pressure valve to ensure smooth system operation; when combined with a directional valve, it can achieve multi-level pressure control of the system; in the brake circuit, the overflow valve can be used to achieve braking action; in the hydraulic test bench system, the overflow valve can be used as a loading valve, etc.