7 replies to this topic

[farid.k]

Is it allowed to close the venting hole at bellow PSV due to leak problem? I don't think so as it will cause problem for the PSV to open due to excessive backpressure. Any other method how to recover the leak at bellow PSV?

[latexman]

I can think of two solutions.  The vent hole can be vented (piped) to a treatment system, as long as no significant backpressure results.  I would assume you'd want to detect the leaking bellows in this case.  Or, you can select a pilot operated PSV instead of a bellows PSV.  This would eliminate the bellows.

 

I'm not sure if a rupture disk (or buckling pin valve or another different technology relief device) instead of the bellows PSV could be a solution to you, or not.

Edited by latexman, 14 November 2015 - 02:27 AM.

[farid.k]

Is it OK to route piping to the safe location? I did go through some other forum and said the same but is it normal practise for bellow PSV leaking?

We cannot down the system thus cannot replace the relief valve.

I can think of two solutions. The vent hole can be vented (piped) to a treatment system, as long as no significant backpressure results. I would assume you'd want to detect the leaking bellows in this case. Or, you can select a pilot operated PSV instead of a bellows PSV. This would eliminate the bellows.

I'm not sure if a rupture disk (or buckling pin valve or another different technology relief device) instead of the bellows PSV could be a solution to you, or not.

[fallah]

Is it OK to route piping to the safe location? I did go through some other forum and said the same but is it normal practise for bellow PSV leaking?

We cannot down the system thus cannot replace the relief valve.

 

.

 

farid.k,

 

Yes, you can pipe away the bonnet vent to a safe location; but it's a normal practice just for the cases that cannot be directed to the close atmosphere, e.g. toxic or high flammable gases...
 

[farid.k]

Flammable gas route to flare?

[fallah]

Flammable gas route to flare?

 

farid.k,

 

To safe location (atmospheric pressure); because firstly the flow just limited to minor leakage and secondly hasn't (and in fact shouldn't have) any positive pressure to be able being routed to flare....
 

[farid.k]

Thanks fallah and latexman for the support

Edited by farid.k, 14 November 2015 - 04:56 AM.

[latexman]

farid.k,

 

You are most welcome.  Don't forget though, a leaking bellows should be replaced/repaired at the first convenient opportunity.  If the openings in the bellows continue to get larger and larger (corrosion, fatigue, etc.) there will come a day when the bellows PSV loses it relatively higher backpressure handing capability and it will act like a conventional PSV.  If this leads to a catastrophic failure (chattering), it could be a very bad day at the factory.