Spring-loaded normally open/closed safety valves are critical pressure relief devices engineered to protect industrial systems from overpressure hazards. Designed with a precision spring mechanism, these valves feature two configurable default states: normally open (NO) (maintaining an open position under standard conditions) or normally closed (NC) (remaining sealed until triggered).

Constructed from robust materials such as carbon steel, stainless steel, or alloy steel, they offer exceptional resistance to high temperatures, corrosion, and pressure fluctuations—suitable for handling liquids, gases, and steam across diverse industrial applications. The valve core integrates a spring-loaded disc that presses against a precision-machined seat, with the spring force pre-calibrated to match the system's maximum allowable working pressure (MAWP).

For normally closed (NC) models—most common for overpressure protection—the valve remains sealed under standard operation. A pre-calibrated high-grade spring exerts downward force on a precision-machined disc. When system pressure rises above the pre-set MAWP, the pressure force overcomes the spring’s tension, lifting the disc to release excess pressure.

For normally open (NO) configurations, the spring holds the disc in an open position during standard conditions, allowing continuous media flow or ventilation. The valve closes only when system pressure drops below a pre-determined threshold or external actuation is applied.