摘要 |
A vapor pressure equalization assembly having an underpressure relief assembly and an overpressure relief assembly in fluidic communication with the vapor space of a liquid storage tank (vessel). The underpressure and overpressure relief assemblies each have movable pistons sealingly engageable with respective sealing members, and biasing members which exert respective biasing forces to maintain the pistons in sealing engagement with the sealing members. A predetermined underpressure or overpressure differential between the vapor space pressure and atmospheric pressure will cause one of the pistons to open fluidic communication of the vapor space to equalize the vapor space pressure with that of the surrounding atmospheric pressure.
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