2 replies to this topic

[Max3008]

Dear all,

Anyone can tell me the reason that pressure safety valve (PSV)  is usually equipped with a bypass valve but thermal relief valve (TRV) is not.

Thanks in advance.

Edited by Hoang Nguyen, 04 September 2014 - 01:09 PM.

[fallah]

Hi,

 

At first it should be noted that considering a by pass line around either PSV or TSV isn't the requirement of any standard/code and only can be seen in some engineering practices as recommendation that a by pass is to be suggested for PSVs.

 

Actually, a by pass line around a PSV might be hepful for relevant equipment purging or depressurizing during maintenance while considering that a TSV is a small size valve (normally 3/4" * 1") with very low liquid relief due to thermal expansion appears mentioned operations in maintenance case wouldn't be so applicable for a pressurized liquid filled equipment/pipe segment on which a TSV has been installed only for protection against over pressure due to thermal expansion... Then it's a normal practice not considering a by pass line for a TSV...

[Max3008]

I get it. Thank you so much Sir.