How does a pressure relief vent plug work - Wuxi Sinceriend New Material Technology Co., Ltd.

A pressure relief vent plug operates on a simple yet precise principle of pressure-sensitive auto-regulation, relying on built-in components to respond dynamically to changes in system pressure. Its design centers on balancing internal and external pressure, ensuring it only activates when needed to maintain safe operation.

Pressure-Sensitive Element

At the core of its functionality lies a pressure-sensitive element—often a flexible diaphragm or a spring-loaded mechanism. This element is calibrated to match the safe pressure range of the system it serves.

When the system's internal pressure remains within this range, the element stays in a closed position, sealing the vent to prevent unwanted leakage of fluids or gases, and keeping contaminants out.

High Pressure Response

When internal pressure rises beyond the calibrated limit, the excess force pushes against the pressure-sensitive element. This force overcomes the element's resistance—whether from the diaphragm's flexibility or the spring's tension—causing the vent to open.

Once open, the surplus pressure escapes through the vent opening, gradually reducing the system's internal pressure. As pressure drops back to the safe range, the element regains its original shape or the spring's tension pulls it back, closing the vent and restoring the system's sealed state.

Low Pressure Response

The plug also addresses low-pressure scenarios that risk vacuum formation. When internal pressure falls below the balanced level, external atmospheric pressure becomes stronger than the internal pressure.

This difference pushes the pressure-sensitive element in the opposite direction, opening the vent to allow external air to enter the system. Once internal and external pressure are balanced again, the element closes the vent once more.

Pressure Regulation Cycle Diagram

Key Operational Features

Automatic pressure regulation without manual intervention
Dual functionality for both overpressure and vacuum scenarios
Calibrated to specific system pressure ranges
Prevents contamination while allowing pressure equalization
Self-resetting mechanism for continuous operation

This cycle of automatic opening and closing—driven solely by pressure changes—enables the plug to work continuously without manual intervention, adapting to varying conditions in closed systems.