Pressure Relief Manway Valve

Hello amit kumar,

That Pressure Relief valve is used for Pressure Relief.

A Manway is a large removeable hatch, to obtain passage way into/out of/passage between internal parts of a large tank or closed unit, allowing a man/woman to pass or crawl through, for either entry/exit or inspection requirements.

So..........Your "pressure relief manway valve", is normally bolted to, as a part of the Manway cover or Hatch, and is used to equalise pressure on both sides of that cover or Hatch.

As you would realise, if the pressures on each side of the Manway cover or Hatch are unequal, and the Manway cover or Hatch is opened, either it may open violently, or not at all, dependent on which way the Manway cover or Hatch opens - Pressure assisted opening, or pressure assisted ensuring remaining shut.

Manway covers are also used extensively in Submarines and/or ships, and some installations have automatic closing versions, normally giving a loud klaxon alarm warning, before closing and sealing in case of fire or flooding.

Hope that assists you....

"Is 5psi dangerous?", asked the curious Engineer.

"Yes", replied the grizzled old Guru, "Particularly if it is propelling a large manhole cover towards you at the time!"