Relief valve construction to minimize ignition hazard from cryogenic storage tanks containing volatile liquids

摘要

A combined second relief valve and restricted orifice is located downstream of the relief valve stack on a vent line. The second relief valve opens at a pressure greater than that of the relief stack. When the second relief valve is closed, vapor is vented through the restricted orifice at high velocity, and when the second relief valve is open, the vapor vents from the unrestricted end of the vent line at high volume.