Rectangular opening in pressure vessel
Rectangular opening in pressure vessel
(OP)
Dear All
My client has vessel and they want to make rectangular opening into the shell. so both PVelite and Compress can not calculate stress on shell due to rectangular Cut/opening( correct me if i am wrong) even nozzle pro . so i wonder if any one here knows any reference to calculate (except FEA Softwar) to calculate the stress on shell?
My client has vessel and they want to make rectangular opening into the shell. so both PVelite and Compress can not calculate stress on shell due to rectangular Cut/opening( correct me if i am wrong) even nozzle pro . so i wonder if any one here knows any reference to calculate (except FEA Softwar) to calculate the stress on shell?





RE: Rectangular opening in pressure vessel
RE: Rectangular opening in pressure vessel
However you should prevent your client that rectangular openings are strongly discouraged (though not prohibited) by ASME VIII: an obround opening is recommended.
prex
http://www.xcalcs.com : Online engineering calculations
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RE: Rectangular opening in pressure vessel
RE: Rectangular opening in pressure vessel
Maybe time to crack the Code book, get out the pencil and paper.
Regards,
Mike
RE: Rectangular opening in pressure vessel
For large openings the code requires to use either 1-7 in combination with UG-36 or 1-10 alone. Both of these chapters seem (silently) fully applicable to round openings only (they refer to the nozzle neck radius Rn) and bothe refer to U-2(g) for specific points. I don't think this opening can be treated with plain code means, an in depth special analysis is required.
prex
http://www.xcalcs.com : Online engineering calculations
http://www.megamag.it : Magnetic brakes and launchers for fun rides
http://www.levitans.com : Air bearing pads
RE: Rectangular opening in pressure vessel
RE: Rectangular opening in pressure vessel
Agreed, the software I am familiar with will not likely adequately address this opening.
As to whether it can be designed per normal rules, possibly not, based on info available I couldn't say.
Regards,
Mike
RE: Rectangular opening in pressure vessel
In this way you may reduce the stresses at the corners of rectangular openings under internal pressure and other effects. (Please do not forget that there will be a thrust force due to the opening end plate.) However I recommend to verify this application by FEA analysis (design by analysis) with a model that includes all the components in the area.
RE: Rectangular opening in pressure vessel
what is the purpose of that opening ? In revamp, big rectangular hole is cut to bring in and out internals quickly. If that is the case, you don't need any code calculation. Just a simple calculation like opening in the skirt. Normally, use L or T steel to temporally reinforce the opening.
We also have rectangular opening come with duct for service, size like 90" x 50" in a FCC unit for a big regenerator. No need to use FEA but just utilize what in the code to reinforce the opening and the duct. Many guys above have touched the point.
Or, is it really a "manway" ?
RE: Rectangular opening in pressure vessel
thanks for answering my question. The purpose of the opening is to cut a sample to inspect shell plate. So they need to cut big chunk of shell to do inspection (microscopic inspection) which they could not do it in place. This exercise is different from Man way and duct opening. So what I thought FEA would be the best solution for this problem. But I want to make sure nowhere in code address these opening.
Regards,
RE: Rectangular opening in pressure vessel
Regards,
Mike
RE: Rectangular opening in pressure vessel
I would think there's got to be a better way of accomplishing whatever it is you're trying to do, though. You'd think if it was microscopic inspection, they could core out a pretty small plug.
RE: Rectangular opening in pressure vessel