5 replies to this topic

[WeikerCL]

Hello everybody.

 

first, sorry for my english, i'm from Chile.

I have a doubt with a little task.

 

I need verify if the pump performance matches with curve pump.

 

This is a simple diagrama of the pump.

 

 

 

 

 

Curve pump shows that the operating point is:

 

 

 

 

As you can see, exists 15m high of discharge, I have a pressure instrument that is reading 1,1 bar and then I have a flowmeter that shows 25 m3/h

 

 

All this pipe is new and I think that I could despise losses and I considered 1,1 bar = 11mH2O + 15m of high...

 

I'll be in 25m3/h @ 26 m ???

 

So, Can I say that performance doesn't match with the curve pump???

 

What other information I could put in my "conclusion"?

 

What (if exist) are the criteria to say "xx bar losses per yy ft of pipe"? etc...  

 

Please, if this topic should be in other forum, forgive me

 

Thank you a lot!!

Edited by WeikerCL, 23 March 2015 - 08:57 AM.

[breizh]

Hi ,

You need first to make yourself familiar with hydraulic calculation , pump curve and system curve .I've attached 2 documents to support .

 

For field data , refer to the chapter 5 of the zip file.

 

 

Note : using the search engine  in this forum , centrifugal pump as key words , you will get a lot of information.

 

Good luck

 

Breizh

Edited by breizh, 19 March 2015 - 11:34 PM.

[fallah]

WeikerCL,

 

Following link is included what you need to understand and perform to reach the target on your query:

 

http://www.cheresour...esistance-curve

[gegio1960]

it is very difficult to understand your scope because of the missed data....

anyway, it seems you have a pump that provides 54 m of head (at 25 m3/h) against a system request of 30-8=22 m plus the distributed + localized pressure drops

the available differential head (54-22-losses=32-losses, m) could be:

- dissipated by a control valve

- utilized to increase the pressure at the end of the system

in order to evaluate the distributed pressure losses you need:

- the pumped liquid physical data: density and viscosity at operating conditions

- the pipe characteristics: size (diameter and schedule), material, length, curves and fittings

once clarified these initial points, you/we can (improve the sketch and the problem definition and) go ahead with other details.... levels, pressures, npsh, power...

moreover, following the advice given by the moderators in previous threads, there is a spanish section in this site and also something to help with the translation (but, technically speaking, a good picture is better than thousand words).

good luck!

Edited by gegio1960, 20 March 2015 - 01:57 AM.

[Zauberberg]

One thing about measuring and reading flow - it can be quite noisy signal resulting in high oscillations and incorrect averaged value. Speak to your Instrument Engineer and check if the flow transmitter has been calibrated recently and see if noise needs to be filtered out. I have seen this on many occasions.

[Padmakar Katre]

 

Hello everybody.

 

first, sorry for my english, i'm from Chile.

I have a doubt with a little task.

 

I need verify if the pump performance matches with curve pump.

 

This is a simple diagrama of the pump.

 

 

 

 

 

Curve pump shows that the operating point is:

 

 

 

 

As you can see, exists 15m high of discharge, I have a pressure instrument that is reading 1,1 bar and then I have a flowmeter that shows 25 m3/h

 

 

All this pipe is new and I think that I could despise losses and I considered 1,1 bar = 11mH2O + 15m of high...

 

I'll be in 25m3/h @ 27 m ???

 

So, Can I say that performance doesn't match with the curve pump???

 

What other information I could put in my "conclusion"?

 

What (if exist) are the criteria to say "xx bar losses per yy ft of pipe"? etc...  

 

Please, if this topic should be in other forum, forgive me

 

Thank you a lot!!

 

 

Hi,

Since the system is existing, you should have all the details such piping isometrics, pump vendor curves, source & destination elevations then set up Pump Hydraulics and see where should be operating point on curves. This detailed assessment would help you to see if the instruments such as PT & FT needs recalibration. Good luck