×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Jobs

using non-dimentional pump curves to detect wear

using non-dimentional pump curves to detect wear

using non-dimentional pump curves to detect wear

(OP)
Does anyone have experience detecting pump wear by looking for changes in non-dimentional pump curves (H-Q) produced from field data on variable speed pumps? I'm thinking of comparing a curve from a new as-installed pump, with one taken at a later time on the same pump

RE: using non-dimentional pump curves to detect wear

To do that, you need to have a flowmeter and pressure transducers installed.

Having done that, you could just tell the system controller to occasionally compare the operating point with the curve for a new pump, and phone you when the pump goes away.

 

Mike Halloran
Pembroke Pines, FL, USA

RE: using non-dimentional pump curves to detect wear

Probably only useful if on a fixed duty instalation, in this case see post from Mike (above).    

RE: using non-dimentional pump curves to detect wear

The problem with "comparing curves" is complicated with variable speed, as you effectively have an infinite number of curves.  You'd have to calculate efficiency from power consumption measured at a given HQ & Speed and compare that to the system-corrected efficiency map of the pump.

**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/

RE: using non-dimentional pump curves to detect wear

(OP)
Thanks Mike. As you point out, flowmeter and pressure transducer are installed, in addition to pump speed sensor which permits non-dimensionalizing based on pump speed (variable) and impeller diamter (obviously a constant). And on line density measurment accounts for change in that variable. So it seems relatively straight forward, but I havent't been able to find reference to any application where this is used in 'real-time'. This is slurry pumping application with high abrasive wear, so this type of monitoring would be valuable. Have you ever seen this type of non-dimensional H-Q monitoring used in practice?
 

RE: using non-dimentional pump curves to detect wear

(OP)
Thanks 'BigInch'. There is a pump speed sensor installed which makes it possible to non-dimensionalize and thus produce one non-dimensionalized pump curve that is speed independant. Do you agree? Have you seen this used in practice?
 

RE: using non-dimentional pump curves to detect wear

Most condition reports I've seen from pump "controls" amount to, "She don't work so good no' mo'.", or words to that effect, in some approximation of English, from an actual person.

If you're running lean and mean, and can't afford a person to grow old with the pump, then, yes, you need the controller to do it, and I concur that it should be possible.

 

Mike Halloran
Pembroke Pines, FL, USA

RE: using non-dimentional pump curves to detect wear

I think this is a pretty basic investigation.
At x speed with y inlet head -- any change to head, flow, and power while factoring in the de-rating for any slurry variables in real time will give you an indication of drooping performance (wear of components). To correlate this into something meaningful might be an other story (other than the pump is now losing performance) but I guess overtime, reduced performance in conjunction with visual inspection of the wear components should be able to give you an indication of the amount of wear measured against any speed increase to maintain output.  

RE: using non-dimentional pump curves to detect wear

If you mean use a given operating point data H,Q,S you measure and convert that to H & Q at rated speed, you could do that as long as the affinity relationships remain valid.

The general method is used by the more advanced pipeline SCADA systems in order to predict for example, what the flowrate should be at any given setting, and to warn operators when some parameters are seen to be deviating from previous history, possibly as an indication that maintenance is required, or when other hydraulic parameters are not consistant, as evidence of pipeline leaks, etc.
 

**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/

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!


Resources