API 610, VS6 Nozzle Calcs

[RBMECH123]

Hello everyone,
I am having a tough time figuring out the correct allowable load factor and/or nozzle calcs to use for my piping analsys off the discharge of a 36" and 42" nozzle. The stress program doesnt allow for vertic shafts and size of the nozzles are larger than 16" which will not work either per API-610 chapter 5. Can anyone help?
Thanks,
Richard

 

[nickelkid]

Can the pump OEM provide allowables?

 

[RBMECH123]

Yes, but do these allowables have a factor that the nozzles cannot exceed? For horizontal pumps, the factor is 2. Plus, the vertical inline are evuluated on principal stress. There is nothing on Vertical Turbine Pumps.

 

[nickelkid]

If the OEM provided a maximum allowable, then that is the maximum allowable. Occasionally the OEM may alleviate their requirements when approached.

Do you have a specific design scenario that cannot meet the specified allowable?

 

[RBMECH123]

Temp 130F and press of 275. The discharge lines are both 36" with 10 feet of pipe exiting then turning down, approximately 10 feet into the ground. Its tight and theres no room for pipe expansion on the exit nozzle direction. I really dont want to bring up expansion joints, but at this point, my best adjustments have been lowering to 5 times the allowable.

 

[nickelkid]

Have you tried to install a spring?

 

[RBMECH123]

The displacements arent showing any vertical movement.

 

[nickelkid]

RBMECH123,

I think the best thing to do is post a detailed sketch and your results on the Piping & Fluid Mechanics thread. This looks like a pipe design issue.