CONSTRUCTUAL QUERIES FOR PRESSURE VESSELS
CONSTRUCTUAL QUERIES FOR PRESSURE VESSELS
(OP)
Hi everybody.
Could somebody explain
1) why in most saddle supported horizontal pressure vessels one saddle has a sloted hole configuration and the other circular?
2) Is it permissible to weld a lifting lug beneath the welding line of a vertical elliptical top headed pressure vessel.?Please provide some standard dwgs if any.
3)For leg supported vertical vessel, with leg beams attached to shell in the diagonal axis how is it possible to perform painting in the small enclosed area between leg and shell (or leg pad) especially if you utilize top ...."rain"..plate cover for legs.?
4) Is it mandotory all external attachments of pressure vessels to be of the same material as shell?
5) Which is the ASME VIII code acceptable minimum clearence between 2 welds (i.e butt type)? If there is not a specific paragraph in the code are there any good engineering practices?
Thanks in advance.....
Could somebody explain
1) why in most saddle supported horizontal pressure vessels one saddle has a sloted hole configuration and the other circular?
2) Is it permissible to weld a lifting lug beneath the welding line of a vertical elliptical top headed pressure vessel.?Please provide some standard dwgs if any.
3)For leg supported vertical vessel, with leg beams attached to shell in the diagonal axis how is it possible to perform painting in the small enclosed area between leg and shell (or leg pad) especially if you utilize top ...."rain"..plate cover for legs.?
4) Is it mandotory all external attachments of pressure vessels to be of the same material as shell?
5) Which is the ASME VIII code acceptable minimum clearence between 2 welds (i.e butt type)? If there is not a specific paragraph in the code are there any good engineering practices?
Thanks in advance.....





RE: CONSTRUCTUAL QUERIES FOR PRESSURE VESSELS
Oh, for "4": No, this is not required. See UG-4(b) for more information.
RE: CONSTRUCTUAL QUERIES FOR PRESSURE VESSELS
2. sure it is....that's the way most are done
3. you close it in with small plates to seal off the inaccessable areas
4. no mandatory. carbon steel vessels should have same P no attachments. alloy vessels should have alloy pads under carbon steel clips if large clips. we normally use alloy attachments just to keep from painting
5. we use 5t between butt welds. you can line up longitudinal seams if 100% radiographed
RE: CONSTRUCTUAL QUERIES FOR PRESSURE VESSELS
Concerning first issue, what happens if the saddle wearplates are not welded to the shell.
Vesselfab could you please clarify the third issue?
Regards..
RE: CONSTRUCTUAL QUERIES FOR PRESSURE VESSELS
The original answer is here:
http://www.eng-tips.com/viewthread.cfm?qid=208212
RE: CONSTRUCTUAL QUERIES FOR PRESSURE VESSELS
I thought vesselfab's response to the third issue was clear enough - if you have inaccessible spaces between the support and the shell, then you seal those spaces by filling the openings with welded plates. The thinking being that if they're sealed, then corrosion won't continue for very long, so you don't need to paint in there.
Cheers,
John