Nozzle Design Calculation

[CSunny]

I need to design a Y fitting that acts as a nozzle to connect two pressure vessels. All 3 sections of the Y is to be made of 2" SS304 pipe. Which part of the ASME code should I use to do the design calculations for this Y ?

Thanks

 

[Cobra17]

U-2(g), and do a burst test to UG-101(m). Or do an FEA.

 

[JStephen]

Could you use conventional fittings (two ells plus a tee, for example?)

 

[SnTMan]

Maybe one of the piping Codes?

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[chicopee]

Do a search on bifurcated joints

 

[r6155]

You can use a 180° elbow properly.
what is the design pressure and temperature?

Regards

 

[CSunny]

The design pressure of the fitting is 240 psi and design temperature is 80f. Our aim is not to connect the tubes in series, so we cannot use a 180 elbow. We can only use a Y joint in our application.

 

[r6155]

Sorry, I was not clear. The Y is made with NPS 2 in the middle of the 180° elbow.
Use the same thickness required by UG-45 ASME VIII Div 1.

Regards

 

[Cobra17]

since it's size on size, if I'm understanding correctly, it's outside VIII-1. Appendix 1-7 only covers a ratio of RN/R of 0.7 or less. As I stated before, U-2(g), and do a burst test to UG-101(m). Or do an FEA.

 

[saplanti]

As it is with the Y connection there will not be any flexibility between the vessels.
In case one vessel moves differentially then the other one the Y nozzle will be overloaded/overstressed, and perhaps will fail. As it is the supports are opposing each other, vessels will grow towards each other under thermal load and this will create additional bending stresses on Y legs. In case the system is not small and identically supported I would suggest to create loop which includes a T connection with flange as suggested. Everything depends on the thermal loading, if any in the system, differential expansion/contraction and the supporting system.

 

[GD2]

There is a procedure for y-fittings in M. W. Kellog handbook.

GDD
Canada

 

[XL83NL]

B31.3 has (had) a code case for this (CC202?), which may have become part of the base code as of 2020, or will be in 2022.

Huub
- You never get what you expect, you only get what you inspect.

 

[CSunny]

@XL83NL
CC202 is for fittings manufactured by forging and casting and is not applicable for welded fittings

 

[XL83NL]

So then you have your answer!

Huub
- You never get what you expect, you only get what you inspect.

 

[CSunny]

@XL83NL

Thank you for directing me to CC202. it sure was a new learning.
No, I don't have a proper solution to this problem yet other than FEA or Burst Test.

 

[SnTMan]

Here is a paper from the old days, it might be useful, might not, you might have to pay for it, might not...

I'd have to think there would be something, somwhere.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[XL83NL]

A solution is CC202. It may imply you have to use a casting or forging, but hey, if you need to comply with B31.3, at least you have an option that (to me) sounds better than FEA or burst testing. Why take all the hassle of 304.7.2?

Huub
- You never get what you expect, you only get what you inspect.