Model 121 Top-mounted, ventless, spring-operated pressure and vacuum relief valve Gases / Liquids
Safety · Pressure-Vacuum Valves
The Storagetech Model 121 pressure and vacuum relief valve provides protection for bulk storage tanks and vessels against overpressure and underpressure conditions. The valves are mounted on the tank roof flange or on a vapor space vent line. In the closed position, the pressure relief pallet and diaphragm assembly are held tightly against a seal to prevent vapor loss to the atmosphere. As the internal tank pressure increases due to product filling and vapor generation, the tank pressure rises and, when the unit set pressure is reached, the diaphragm opens and releases gas to the atmosphere. The opening set point can be selected within a range between +61 mbar and +1000 mbar (+24 in. W.C. and 400 in. W.C.), and the valve will reclose when the tank returns to a safe pressure.
