May 17, 2024, 08:14:52 PM
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Topic: PSVs Inlet and Outlet lines  (Read 8522 times)

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PSVs Inlet and Outlet lines
« on: June 17, 2006, 09:21:36 AM »
Dear All,

1. Can PSV outlet line reach sonic velocity???

2. And is that correct that API suggests that Inlet line pressure drop should be 3% of set pressure and outline line pressure drop should not create backpressure more than 10% of the set pressure??

3. A PSV orifice designation has more than one inlet outlet sizes; What is the criteria or basis of selecting particular inlet outlet size for a specific designation??

Best Regards,

Offline mbeychok

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Re: PSVs Inlet and Outlet lines
« Reply #1 on: June 17, 2006, 03:20:06 PM »

In answer to your questions:

(1) Yes, the linear velocity (i.e., m/s) of the gas can reach sonic velocity in the PSV. See the posting on "Choked Flow" in this thread at

(2) and (3): I strongly recommend that you register on the online forum at and ask your questions at the "Relief Devices Forum" at that site.
Milton Beychok
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