Pilot Operated Pressure/Vacuum Relief Valve

A high-performance pilot operated pressure/vacuum relief valve designed for low-pressure atmospheric storage tanks and process vessels handling volatile, corrosive, or cryogenic media. Unlike weight-loaded or spring-loaded relief valves, the pilot operated design uses tank pressure itself to actuate the main valve, enabling the operating pressure to be set much closer to the tank’s maximum allowable working pressure (MAWP) — significantly reducing evaporation losses, product loss, and the cost of processing emissions compared to conventional alternatives.

The pilot valve continuously senses tank pressure and directs actuation signals to the main valve. Below set pressure, the main valve remains fully closed and leak-tight, minimizing fugitive emissions. At set pressure, the pilot opens and the main valve lifts rapidly to full open at just 10% overpressure, delivering full rated discharge capacity. The pilot valve can be configured for either snap-action or modulating operation depending on the application. Valve seats and internals are manufactured from advanced composite materials, providing superior resistance to corrosion, chemical attack, liquid viscosity, and freeze bonding across a broad operating temperature range. Designed and tested in accordance with API 2000.

• Pilot-actuated main valve maintains full seat tightness up to set pressure, minimizing fugitive emissions and product evaporation loss
• Fully open at 10% overpressure for fast, high-capacity discharge when needed
• Operating pressure can be set closer to tank MAWP than weight-loaded or spring-loaded designs, increasing storage efficiency
• Snap-action or modulating pilot operation selectable via blowdown needle adjustment
• Advanced composite PPS valve seats and cores for superior corrosion, chemical, and viscosity resistance
• Fail-open mode of failure — if pilot components fail, the main valve vents to atmosphere rather than remaining closed
• Suitable for cryogenic, low-temperature, corrosive, acid, and ammonia service
• Field-replaceable valve core and seat — no special tools required
• Compatible with natural gas, low-pressure process, wastewater, and blower/conveying system applications