Hello, today I'm working on the design of a jacketed vessel.

The design of the manhole nozzle is making me think that there's something unclear in ASME App.9.

I'm attaching a pdf representing the detail that I'm speaking of.

I have modeled the vessel shell in a .pvi file, added the manhole nozzle and checked it both with internal pressure (6bar) and jacket/external pressure (4bar).
The resulting design requires a reinforcing pad, and this makes sense to me.
But then I tried to check the jacket with a second .pvi file, and I wanted to check the nozzle opening in the jacket too (because App.9-6(a) says that opening through jacket must meet the usual nozzle design).
A repad would be necessary too... but then APP.9-6(b) clearly states that no repad is required for the jacket side, because the nozzle neck itself is acting as a restraint for the jacket.
This is confusing to me, because it looks like that APP.9-6(a) and APP.9-6(b) are in contradiction.

So, I have a couple of questions about this situation:
1) I think that APP.9-6(b) governs because it refers only to Fig.9-6 details... is my interpretation correct? NO repad is required on the jacket?
2) if yes... how would you work out the pvelite design report, in order to show that APP.9-6(b) has been considered, demonstrating that the holes on the jacket have not been forgotten by the designer ... (it would be nice to have this kind of check implemented into the new "jacket module").

By the way, isn't it weird that the jacket chamber shows a reinforcing pad on a 16mm head and NO reinforcing pad on the 10 mm jacket?
To me, this doesn't make much sense.

I'm looking forward to read your opinion!

Federico


Attachments
jacket nozzle detail.pdf (438 downloads)



Edited by fedeghi (03/22/11 05:02 AM)