2 replies to this topic

[KeJoSa2010]

Hello,

Can someone give me a brief description of how a Pressure Vacuum Safety Valve actually works? I know that is protects low pressure tanks from both overpressure or vacuum conditions (in the cases where the tank is being emptied); however, the P&IDs that I am looking at show that the set pressure for these valves are in the range of 4-6 oz. What does a 4 oz set pressure mean exactly? Is this for inbreathing, outbreathing...both? Again, I am very new to tank relief design so I would appreciate any help.

Thanks!

[fallah]

KeJoSa2010,

Oz itself is a weight unit such that 1oz is equal to 28.350 gr. On the other hand oz/in2 is a pressure unit such that 1oz/in2 is equal to 4.3 mbar, then 4 oz/in2 (or 4 oz in brief) would be 17.2 mbar. To find a description for PVSV operation you can use googling.

Edited by fallah, 15 January 2013 - 12:27 PM.

[Ajay S. Satpute]

Hi,

Please refer below link for a vendor catalogue for better understanding.
http://www.grothcorp...rialCatalog.pdf

You may also check API 2521 (Use of pressure vacuum valves for atmospheric pressure tanks to reduce evaporation loss).

Regards.

Ajay