Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Minimum Flow Values....

Minimum Flow Values....

Minimum Flow Values....


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


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....

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....


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


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.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close