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Minimum Flow Values....

Minimum Flow Values....

(OP)
Hello;

Minimum flow value increases or decreases, which one is the more avail of process???

Thanks..

RE: Minimum Flow Values....

Must be increase as decrease is already minimum - however not sure what the real question is.
Might be a good idea to expand your questions - you might know what you are thinking but we don't.

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.)

RE: Minimum Flow Values....

(OP)
I request <180 m^3 minimum flow value but vendor proposes 140 m^3 and 160 m^3 which one is the best value for process.

I hope it would be more clear....

Thanks...

RE: Minimum Flow Values....

Up to you, both are within your requirement of <180.

Look at other aspects such as power consumed at duty point, closeness to BEP etc

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Minimum Flow Values....

If the vendor quoted a lower minimum flow there is no problem - there is no reason why you have to operate below your specified minimum flow - can not understand what your concern is.

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.)

RE: Minimum Flow Values....

A lower minimum flow may indicate a lower NPSHr which necessarily results in a higher suction specific speed and suction energy. If the minimum flow was excessively low, this would be a red flag for me to look closer at Nss and suction energy. High suction specific speed and very high suction energy can contribute to a limited stable operating range and in some cases, poor reliability.

Johnny Pellin

RE: Minimum Flow Values....

Not exactly clear of your question, but to add some information for you...

Finger in the air, a single stage end suction pump needs a minimum flow mainly to avoid heat generation in the pump head, rule of thumb is 10% of flow ab Best Efficiency point for intermittent duty, or we recommend 20% for a metallic magnetic drive operating 24/7 x 365 days per year due to eddy current heat generation.

There are also other considerations such as hydraulic forces to consider at low flow too, but wont go into too much detail about that at this point.

Not sure if this helps at all, but thought i would throw it out there...

Ash Fenn

www.cdrpumps.co.uk

RE: Minimum Flow Values....

Minimum continuous stable flow (MCSF) is the lowest flow at which the pump operate without exceeding the vibration limits imposed by API 610. MCSF shall be determined by Vendor and not Purchaser, When Vendor determined 140 m3/hr why did you propose 180m3/hr!!? This will cause AOR of the pump to be decreased and you will have a narrow performance curve which may not be an economic selection.

Shahab Zardynezhad

RE: Minimum Flow Values....

Don't believe that anyone can provide you with a good answer without knowing the application, type of pump and operating parameters. Without this information, it is just a guess.

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