SR elbow

[boudjema]

hello,
for space problem inside a pressure vessel a short radius elbow is requested to be installed on internal piping instead of long radius one.
- is there any impact if installing short radius and what is the alternative solution.
regards

 

[mk3223]

What's the process for the vessel?
IMO, no mechanical issue for using SR elbow for the pressure vessel if there is no problems of the high fluid velocity, erosion, etc.

 

[pennpiper]

The easy answer is "No" there would be no problem.
However you did not provide any detailed information to be able to give a proper answer.

Sometimes its possible to do all the right things and still get bad results

 

[LittleInch]

Possible stress issues come to mind, also potential erosion.

Alternatives? Piping redesign? Thicker elbow?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[MJCronin]

I agree with LittleInch....There are stress issues.

If the piping system is to undergo a detailed (computer) stress analysis, it is quickly discovered that the SR elbow has a very high Stress Intensification factor and often becomes the highest stress point of the system.

Stress intensification factors are defined in the Appendicies to the ASME B31.1 and B31.3 Piping codes.

http://www.whatispiping.com/bend-sif

Piping designers should always use LR elbows in their designs. SR elbows should only be used in extreme cases.

Short radius elbows also have a higher pressure drop than LR elbows

MJCronin
Sr. Process Engineer

 

[pennpiper]

boudjema.
Please give us a sketch (Drawing) or description that defines where and how this Short Radius Elbow is used.
Include:
- The Inlet or outlet pipe this Elbow is connected to outside the Vessel
- The diameter of the Vessel
- What if anything is connect to the SR Elbow inside the Vessel
- Description of the support (if any) for the internal piping and Elbow

Sometimes its possible to do all the right things and still get bad results