Recent content by DMay121

So is the stress in a formed head direction-dependent? Or can it be assumed to be Omni-directional? In a shell, it makes sense to orient an elliptical manway with the shortest diameter in the longitudinal direction (since that places the smallest area normal to the circumferential stress). If...

Hey all, I am trying to determine which diameter to use in reinforcement calculations for a 12"x16" manway that is inserted into an ellipsoidal head. I know on the shell there is the F factor to take into account the difference between longitudinal and circumferential stresses, but I am not...

@bimr The concern at the present time is that the designers of the system might have incorrectly designed it so that components are in danger of failure if a regulator fails. @LittleInch I know that the 104 is meaningless, but in API 520 terms, its what the relief valve could be set at to...

@bimr This system has been in use for 10+ years and is a gaseous nitrogen. @LittleInch Okay this is all making sense now, but I have one question: This specific situation has 2 panels. The second panel has no relief valve but is entirely fed by the first panel that has a relief valve d/s of...

@Latexman The orifice in question has an opening of 0.025" and is definitely smaller than the regulator. @LittleInch I am looking at a bunch of nitrogen panels and there are orifices right before a lot of the pressure gauges (which I do not understand) of different pressure ranges. These...

Which equation should I use to determine the resulting pressure downstream of an orifice given an upstream pressure, orifice size, etc.?

But wont the orifice within the regulator result in a drop in pressure across the regulator even when it fails? And I know what scfm means, I just do not understand what an orifice rated for 8.1 scfm entails. Flow changes with u/s pressure and incoming flow, so how is it rated for a certain...

Howdy! I am trying to understand the fluid mechanics theory to understand a problem I am trying to solve. Say I have a system that has 2640 psig inlet pressure. This flow goes through a regulator and then through an orifice which leads to a pressure gauge that has a range of -30-0-30 psig. If...

Well, without going into too much detail, I am writing a report that will urge the facility to install a new relief valve. The regulator in question was manufactured in the 60's, so its probably been refurbed a few times. Regardless, ~1800 scfm will take the system to over three times its MOP...

Doh! A case of the Fridays it is. Should have been 703 psi and 731 psig, not SCFM.

Those are the exact numbers I got. This is conclusive for me that I am on the right track now. Thanks again!

The Cv of the regulator is 0.6. EDIT: The Cv calculator you provided, when solving the air/gas equation for Q using the Cv for the regulator results in a flow of 703 CFM. Using another Cv equation that I have found from Swagelok and Sandia National Laboratory results in a Q of 731 SCFM...

I can see how both of your viewpoints stem from varying things I have said. I will attempt to start from the beginning but add updated info: I am trying to determine if the relief valve d/s of a regulator will be able to maintain 120% system MOP if the regulator were to fail. u/s of the...

Alright, follow up question time. Are manufacturer flow charts applicable for a state of failure for a regulator? Or are they only applicable assuming normal operating conditions? Using Cv equations from literature produce flow rates that greatly differ from manufacturer flow charts. Thanks again!

I work with a safety office and am definitely aware of the possible ramifications, which is why I want to be perfectly sure that my methods and line of thinking are correct. Thanks to everyone who provided input and helped, it is greatly appreciated.