Experience with Segmented MultiStage Pumps

[Aub_Engineer]

8 stage SERO pumps are installed in ammonia service and have historically been unreliable. The mechanical seal life is very low, ~ 1 year MTBF. I'm curious if others have had experience with these types of pumps. The allowable nozzle loads are so small compared to API 610 pumps that I'm used to seeing. (<75 lbf forces and <50 ft-lbs moments).

Does anyone reading this forum have experience with these they could share? Good/Bad?

 

[Artisi]

Ideally there shouldn't be any forces applied to the pump flanges.
Have you involved the seal manufacturer in the seal problems, it might just be a poor seal selection.

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.)

 

[spartan117]

The mechanical seal tolerances are very sensitive to the nozzle loads. I agree with Artisi, but the reality is that piping is often restricted by space, and therefore, the final piping design leaves some residual forces acting on the pump. It is likely the nozzle loads are affecting the mechanical seal function.