Upgraded material for pump impellers in sea water application 1

[Mech5656]

Hello,

We have a pump used in sea water that needs repair and the impellers are washed out and pitted. Impellers are made from Bronze 630 and we are thinking to upgrade them to 316 SST. Is that a good upgrade? Do you recommend 316 SST instead of bronze in sea water?

I have attached picture of impeller condition after removing from sea water. Unfortunately, we don’t know how old these impellers are because of no documentation left by previous owner.

 

[Mech5656]

EdStainless:
Financially, we are not in good shape to replace the pump with new one. Also, the lead time will be longer in case of new pump. Thanks for your suggestion.

For other mates, looking for better material in sea water application, here is what I have found:

Super Duplex Stainless Steel
Duplex Stainless Steel
Ni-Al Bronze
316 Stainless Steel

 

[TugboatEng]

No wonder you're not financially in good shape if you're willing to tolerate this kind of wear. A simple orifice plate may be all that is required to stop this wear.

These types of systems have generally have very short piping runs of generously sized pipe. Flow only passes through a single plate type heat exchanger. The vertical rise is in the 10's of feet. There is very little resistance to flow which pushes you to the right side of the pump curve where cavitation becomes severe.

Have a look at your temperature control valve? What % opening does it normally see?

Trimming the impeller is also an option but expensive if you go too far. You could also consider variable speed drive.

 

[Artisi]

Round and round in circles, as usual -, so far not one piece of data regarding the operating conditions / versus pump performance - just hung up on nonsense regarding materials that is irrelevant until the pump operation is understood.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)