Pressure Relief Valve

Proportional Relief Valve

Proportional relief valves, also known as proportional pressure control valves, are hydraulic valves that are designed to maintain a constant pressure in a hydraulic system, regardless of changes in the system's flow rate. They operate by diverting excess fluid flow away from the system's working components and back to the reservoir, thereby maintaining a constant system pressure.

Proportional relief valves are typically used in hydraulic systems that require precise pressure control, such as in machine tools, injection molding machines, and metalworking machinery. They can also be used in mobile hydraulic applications, such as construction equipment and agricultural machinery.

In addition to maintaining a constant pressure, proportional relief valves can also provide other features, such as temperature control, pressure sequencing, and remote control options. They are available in a variety of sizes and configurations, and can be customized to meet specific system requirements.

Product Description


  • When the system pressure reaches the set pressure, the relief valve opens, and when the system pressure drops below the set pressure, it closes.

  • The relief valve is selected and installed with a spring that covers the desired set pressure and the corresponding label is affixed to the cap.

  • For valves that have not been used for a period of time, the initial relief pressure may be higher than the set pressure.

  • Set pressure and resealing pressure:

                The set pressure is the upstream pressure at which fluid first flows out. At room temperature, the set pressure of each valve can be repeated within ±5% after initial relief.

                The resealing pressure is the upstream pressure with no fluid flow and is always lower than the set pressure.

  • Preset pressure = desired pressure - 0.8 * back pressure

  • Working temperature: -23°C to 148°C (-10°F to 300°F)

  • Adjustable valve cap for adjusting the set pressure.

  • Anti-loosening hole can effectively maintain the set pressure.

  • Multiple sealing materials are available.

  • Interface size:

    1/4" to 1", 6 to 12 mm double ferrule fitting

    1/4" to 1" thread

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