Pump Piping Straight Run Origin

[shvet]

Good day, forum

As we know there are a lot of documents that define pump upstream and downstream piping (please expand the list if you know any more):
- ANSI/HI 9.6.6
- API 686
- CEN/TR 13932

All of these documents state that any pump shall have proper inlet and outlet piping geometry to work properly. All this is Ok and well understood. My question is - what will happen if I don't follow one of these document? Let's say suction pipe slope, gas pockets and straight run. I'm not a young engineer and understand that fotos of eroded impeller and vibrating bearings are not so terrible if fotos were made after 10-20 years of nonstop work. 2 months and 2 years online is a big difference. Can you share a good report, survey or research which states why proper piping is so important and what consequence are?

 

[yousif aldossary]

good day
since you mentioned that you are not young engineer you should know what are the technical issues in case we have inappropriate piping configuration.

from commercial point view you cant sell or certify any pump or piping configuration unless it complies with the stated standards above.

if a customer complains about any equipment even if its warranty was expired , and if the customer prooves that the equipment doesnt comply with applicable design code , he can back charge every thing even maintenance and lapor costs from the supplier and the supplier won't have any chance to win any type of these cases.

regards

 

[DGrayPPD]

Taken from the Piping Handbook 7th Edition,

"The piping of centrifugal pumps, particularly the suction piping, can seriously affect the operating efficiency and life expectancy of the pump. Poorly designed suction piping can result in the entrainment of air or vapor into the pump and cause cavitation, which displaces liquid from within the pump casing, results in vibrations, and throws the pump out of balance. The cavitation alone can result in severe erosion of the impeller. The out-of-balance condition may result in a slight eccentric shaft rotation, which will eventually wear out the pump bearings and seals, requiring a pump shutdown for overhaul."

I'm sure you are aware of all this, however as a designer who has spent countless hours researching of mine own, I can tell you that any website/article/book/report is going to say pretty much the same things.

 

[lilliput1]

Available NPSH must exceed pump required NPSH otherwise the pump will be no good as stated by DGrayPPD. Submerged pumps must have good intake flow and more than their required minimum submergence otherwise pump will be no good as stated by DGrayPPD.

 

[shvet]

@DGrayPPD
Thanks

@lilliput1
NPSHR<NPSHA is not enough for pump to work properly. See standards mentioned in first post.