Pressure Relief Valve

The pressure relief valve is an automatic safety protection device. When the medium pressure within the system exceeds the preset safety value, it automatically opens and discharges a portion of the medium, allowing the pressure to return to a safe range, thereby protecting equipment, pipelines, and personnel.

Core Operating Principle

The pressure relief valve is equipped with an internal loading mechanism, such as a spring or weight, which applies a downward closing force to the valve disc. When the upward thrust generated by the system medium pressure is less than the set closing force, the valve remains closed. Once the medium pressure exceeds the set value, the thrust overcomes the closing force, lifting the valve disc and allowing the medium to discharge through the outlet. After the pressure drops below the set value, the valve automatically recloses.

Main Classifications

- Spring-Loaded Pressure Relief Valve: Relies on spring preload to set the opening pressure. Compact structure and most widely used, suitable for most medium-to-low pressure applications.

- Weight-Loaded Pressure Relief Valve: Sets pressure via a lever and weight mechanism. Offers stable and reliable operation, often used in high-temperature applications such as boilers and pressure vessels.

- Pilot-Operated Pressure Relief Valve: Composed of a main valve and a pilot valve. The pilot valve senses pressure and controls the opening/closing of the main valve. Features excellent sealing performance and large discharge capacity, suitable for high-pressure, large-diameter systems.

- Pulse-Type Pressure Relief Valve: Suitable for high-temperature, high-pressure steam and similar applications. Features smooth opening and closing cycles to reduce water hammer impact.

Application Scenarios

- Overpressure protection for boilers, pressure vessels, and pressure piping

- Petrochemical and natural gas transmission pipeline networks

- Pressure regulation in hydraulic and pneumatic systems

- Fire protection water supply systems and HVAC systems

- Storage tanks, reactors, and other chemical equipment