ASME Section VIII Div 1 UG-37 area replacement 2

[flummoxed2002]

Hello everyone,

I am trying to design the reinforcement for a new nozzle and found that the current layout I have is not support by the program Codecalc. I have resorted to doing the area replacement calculation by hand, but was wondering if the methods described in ASME VIII Div 1 UG-37 are not valid for a certain large theta or x values as shown in my diagram. Any advice on the matter would be greatly appreciated. Thank you in advance!

 

[SnTMan]

flummoxed2002, Codecalc should do this calculation, are you sure your inputs are right on the Shell/Head page?

Are your dimension such that the nozzle is tangent? Is the nozzle OD outside the shell OD maybe?

Regards,

Mike

 

[trottiey]

It's just a hillside nozzle. UG-37 should be valid. See example 7.7 in Appendix L, or a more detailed discussion in this document:

http://www.pdhonline.org/courses/m205/m205content.pdf

Codecalc's marketing material says it can do it, although I haven't used it myself.

 

[flummoxed2002]

Thanks for the advice. I thought it was strange that I couldn't model this. I must have missed something when I was input everything into the program. I'll take another shot at it.

 

[flummoxed2002]

Ok, seems like I completly misunderstood what the value L1 meant in codecalc. It works now.

One last question. Is there some way to combine a hillside nozzle and an angled lateral nozzle? In my scenario I have a hillside nozzle as described above that is angled upwards from the horizontal a couple degrees. This will obviously increase the cutout from the vessel which needs to be accounted for.

Again, any help would be much appreciated.

 

[Duwe6]

trottiey, please check my reasoning;

Use vector addition to get the combined angle from the repad area, then use that derived [larger] angle to compute the minimum size for the repad. In other words, 'trick' CODECALC into thinking that this is a simple angle [which it can calc] versus a compound angle [that it can't].

 

[trottiey]

Boy, that's not an easy problem. The compound angle of non-intersecting axes? Would you then use that as hillside angle or an incline angle or try both? It sounds about right, but it would take a lot of math to verify that it's conservative. Consider that a hillside opening only has one plane of symmetry, not two, and that should make you wary of simple linear superpositions.

But for a couple of degrees of inclination, I would just process the diameter twice. Figure out d' due to 2 deg inclination, then use that enlarged d as input for the hillside calculation. It's bound to be over-conservative, but for 2 degrees it shouldn't matter.