Cone-to-flange reinforcement

[johnnymist2003]

Hi all,

perhaps some assistance here. I have an heat exchanger, fixed tubesheet, which is extended for bolting on the inlet and outlet channels via girth flanges. Tubeside has a single pass. The inlet and outlet nozzles are on the same horizontal centreline as the tubesheet. They are NPS 30 in size. Each of the nozzles are connected to conical sections, from NPS 30 to 1400 mm I.D. My question is this. May the conical sections be welded directly to the NPS 30 flange (which is connectetd to piping) and then at the other end onto the 1400 mm I.D. girth flange which is then bolted onto the tubesheet. The reason I ask is that ASME VIII, Div.1 sets up limits for reinforcement of the large and small ends of the conical section and assumes that there is some area available in the small and large end cylinders. How does one account for this requirement if the cones are welded directly to flanges ?
John

 

[prex]

You may provide the end reinforcements of the cone only on cone side, not accounting for any contribution from the flanges (hopefully WN type).
In my opinion in this way you are allowed to weld directly the cone onto the flanges.

prex

http://www.xcalcs.com

Online tools for structural design

 

[deanc]

Is this for water? What pressure are the inlet and outlet under? What did you design your tubesheet to? UHX,TEMA?

 

[johnnymist2003]

Hi Prex,

after reading the relevant sections of the code again what u said is exactly what I have done. Nice to have someone else's input, though.
Thanx
John

 

[deanc]

My point was missed here. If the circumstances are right you may be able to exempt this perU-1(c)(2). If not Appendix 1-5,Appendix 2,and possibly UHX will apply. Suggest you see UG-40(e).

I have no problem with prex's answer. There is no reason not to take advantage of this if you can.

 

[johnnymist2003]

Hi deanc,

unfortunately I cannot apply U-1(c)(2). The tubesheet is designed to TEMA, also UG-40(e) will not apply as the configuration is not for a nozzle, it is similar to the diagram for the BEM exchanger in TEMA. I was enquiring about the channel end, with cone as shown. Thanx for your input, though.
John