Two inlets for a PSV

[KVVS]

Hi every one
during P&ID checking , I saw several place two inlets provided for single PSV. it gave me little surprise . can any one explain the purpose of the same.

thanx in advane.

 

[Chance17]

At least one of the inlets must be equal to the the PSV size.
If this criteria is not meet, the installation does not meet Code.
I have seen dual inlets on either side of an internal baffel (horiz vessel).
I have also seen upstream and downstream of demister pads (vert vessel).
Do your applications have internals?

 

[KVVS]

Thanks chance17 for reply.........dear my PSV placed on heat exchanger discharge line so there is no internals ........but as you say one line size out of two exactly equal to the PSV size. kindly tell me there is any specific requirement to put such type pSV.

 

[rustbuster]

KVVS,

If you could scan a pdf of your P&ID we might have a better idea of what you need.

 

[someguy79]

If a flow path between the two taps feeding to the PSV is acceptable, application might be OK.

In cases where a sudden and relatively small differential pressure can cause problems, two taps feeding one PSV can be used. This can eliminate equipment damage to internals like mist eliminator pads (as mentioned) or fluidizing packed vessels.

Without knowing more about the process you're considering, it's difficult to give any decisive advice.

 

[KVVS]

thanks someguy79