Minimum Continuous Stable Flow and Pump Allowable Operating Range

[Sawsan311]

Dear All,

I have always perceived that the edge of the AOR for the pump determines the minimum continuous stable flow for pump's operationg above the API 610 vibration limits. Is it possible to have the MCSF below (less than) the left edge of the AOR? I have seen some vendor who have shown stated that pump AOR left edge is 170 m3/hr while specifying MCSF as 155 m3/hr. Please note that I am not referring to MSTF (minimum continuous thermal flow which is even to the left of the MCSF) in most of the applications.

Regards,

 

[RVAmeche]

Some vendors screw up MCSF and MCTF, or list "minimum flow" without specifying which is which.

If they fully call out MCSF, ask the vendor for confirmation and point out your concerns. I've had a project where we took it for granted that the chart was labeled correctly and had tons of bearing issues and rework after construction, since they meant "thermal flow" instead of "continuous flow".

Per API 610, the MCSF normally coincides with the left edge of the AOR. It doesn't make sense to me that the MCSF would be outside the AOR, since by definition its a stable/acceptable flow point.

 

[Sawsan311]

Thanks Alot RVAmeche , I totally agree with you..