Literature on Nozzle flexibilites 3

[ikshwaku]

Hi

I'm looking for recent papers that discuss methods of calculating nozzle flexibilites. Have looked at WRC 297 and will be taking a closer look at the references indicated in this paper. Does anyone know of some other papers that would fit the bill? Thanks in advance.

 

[jte]

ikshwaku-

Take a look at the 2003 Addenda API-650 Appendix P.3.

As for papers, consider Lengsfeld, et. al. "Stiffness Coefficients for Nozzles in API 650 Tanks" published at the 2002 ASME Pressure Vessels and Piping conference. Available at

http://store.asme.org/product.asp?c...Papers&category_name=&product_id=PVP2002-1279

for $15.

jt

 

[JStephen]

Are you looking at vessels or field-erected tanks?

API-650 has some information in it applicable to larger tanks. It has been a while since I worked through it, but there are several frustrations. It has been revised to show that it is applicable to 100' diameter or greater (as I recall, the derivations assumed wall thickness proportional to pressure, which is only valid for larger tanks). I recall, too, that the curves were so far apart, on logarithmic scales, that it was difficult to interpolate between the curves with any degree of confidence.

 

[KernOily]

To add to the frustration, there are gazillions of API650 tanks that are under 100' in diameter. I have had to build FEA or RISA models of the nozzles when I needed a stiffness - a hassle. So maybe this paper will help. jte - you are a veritable fountain of knowledge - thanks for the link. ;-)

Thanks!
Pete

 

[ikshwaku]

Thank you for your responses. To clarify, I'm looking for papers that deal specifically with pressure vessels.

 

[arto]

Check these out:
H.H. Bednar, "Pressure Vessel Design Handbook," 2nd ed., Van Nostrand Reinhold 1986. Ch. 7 has a greatly simplified & easy to use method.

Walther J. Stikvoort's articles:
"Proper Interface Design for Pressure Vessels" in Chemical Engineering June '94 p133-4.

"Piping Reaactions on Pressure Vessel Nozzles" in Chemical Engineering, July 7, '86 pp51-3.

"Pressure Vessel Design, Nozzle Piping Reactions" in Encyclopedia of Chemical Processing & Design,Vol.42, [NY:Marcel Dekker] 1993, pp 237-44.

Also: C.J. Dekker, "External Loads on Nozzles," Int.Jnl Pres. Ves. & Piping, 53(1993) p.335-350.

 

[KernOily]

Good stuff arto, thanks. Pete

Thanks!
Pete

 

[jte]

JStephen et. al.-

Your frustration with the diameter limit (greather than 120') was noted. The 2003 Addenda renumbered the paragraphs in Appendix P and added a new section to it, "P.3 Alternate Procedure for the Evaluation of External Loads on Tank Shell Openings." From the Scope paragraph: "... The method is valid for all practical sizes of tanks." The tanks which were evaluated to form the basis of the new section ranged in diameter from 30' to 300'. Be aware that this is a new section and some typos are most likely present. Use the new section accordingly. Although the application this procedure was developed for was API-650 tanks, the procedure is not necesserely limited to 650 tanks. Other tanks or vessels with similar geometry could also be reasonably evaluated with this method.

See also thread809-103689

jt

 

[ikshwaku]

Those are some great leads Arto, thanks!

It seems there may be a few others interested in this topic so I'll post any worthwhile references I come across in my own literature search re: determination of vessel nozzle flexibilities.

Cheers

 

[codeeng]

FEA software such as NozzlePro establishes spring rates for nozzle to shell/head geometries and is not limited to size or d/D ratio. I find this tool very useful in providing our pipe stress guys with the means to reduce those ever increasing pipe loads.

 

[juancito]

If I recall good, BS5500 has a chapter (or section) in which you can calculate nozzles deflection and displacement.
Hope this helps