Breathing Safety Relief Valve (Pressure/Vacuum Relief Valve)

A weight-loaded pressure/vacuum relief valve designed for overpressure and vacuum protection on fixed-roof atmospheric storage tanks and tank trucks handling light petroleum products. Installed on the tank nozzle opening, the valve serves as a secondary backup safety device to the primary breather valve — activating at a slightly higher pressure and vacuum threshold to protect the tank in the event of primary valve failure or freezing in cold weather conditions. By allowing the tank to safely inhale and exhale in response to pressure fluctuations caused by filling, emptying, and thermal changes, the valve minimizes product evaporation loss while preventing structural damage from over-pressurization or implosion. Sized and designed in accordance with API 2000 for venting atmospheric and low-pressure storage tanks, and compliant with DOT regulations for cargo tank trucks.

• Acts as a secondary safety backup when the primary breather valve fails or freezes in cold weather
• Dual-action protection — opens to relieve overpressure during filling or thermal expansion, and opens to admit air during emptying or thermal contraction
• Liquid seal mechanism activates to protect the tank from damage when primary valve is compromised
• Minimizes product evaporation loss under normal operating conditions
• Weight-loaded pallet design for reliable, low-set-pressure operation
• Suitable for cast steel and stainless steel construction for compatibility with a range of petroleum products
• Compliant with API 2000 and DOT requirements for cargo tank pressure relief systems