Efficiency tests for pumps in operation
Efficiency tests for pumps in operation
(OP)
Gents,
Does anyone have ideas on how to carry out pump efficiency tests for pumps in parallel and in operation, without having to stop any one of the other pumps that are not on test (centrigugal pumps and recips as well).
What are the consequences of "no-flow" tests while in operation. Can it be carried out while all pumps are in operation without affecting any of the pumps, and can it replace efficiency tests in a crude pumping station ?
I have also looked for International standards for procedures on efficiency tests. Does anyone know of any ?
Does anyone have ideas on how to carry out pump efficiency tests for pumps in parallel and in operation, without having to stop any one of the other pumps that are not on test (centrigugal pumps and recips as well).
What are the consequences of "no-flow" tests while in operation. Can it be carried out while all pumps are in operation without affecting any of the pumps, and can it replace efficiency tests in a crude pumping station ?
I have also looked for International standards for procedures on efficiency tests. Does anyone know of any ?





RE: Efficiency tests for pumps in operation
RE: Efficiency tests for pumps in operation
Well one could carry out a "Wire to Water" test but you should realise that running pumps in parrellel would not give you a proper reading for each pump as although the TDH would remain relaitivly the same, the flow does not double as most people seem to think. Another problem would be if the pumps in parrellel do not have the same duty.
I wish you luck in your struggle and hopfully some bright spark will guide us all to the path of enlightenment !
RE: Efficiency tests for pumps in operation
Well one could carry out a "Wire to Water" test but you should realise that running pumps in parrellel would not give you a proper reading for each pump as although the TDH would remain relaitivly the same, the flow does not double as most people seem to think. Another problem would be if the pumps in parrellel do not have the same duty.
I wish you luck in your struggle and hopfully some bright spark will guide us all to the path of enlightenment !
RE: Efficiency tests for pumps in operation
I think this no-flow test would only be valuable if you can manipulate your system to isolate the discharge of the pump under test from other pumps (and still able to measure discharge pressure). The test would be limited if you tried to conduct it on multiple pumps all feeding in parallel to a shutoff header, since the performance of a weak pump would be masked by the performance of a strong pump.
If you have the ability to measure the individual flow (and dp and fluid temperature) on each pump, then you can locate the performance of that pump on its own curve regardless of what other pumps are in operation. Otherwise (if no individual flow info) you'll have to make some assumptions regarding the sharing of load which will decrease the ability to accurately evaluate each pump.
Note that flow measurements can often be made with temporary ultrasonic info outside of the pipe.
As it stands your question is pretty wide open. Can you clarify what you are trying to accomplish?
RE: Efficiency tests for pumps in operation
RE: Efficiency tests for pumps in operation
If you have the baseline information on your pumps from when they were installed, tracking flow vs current draw on your motors should give you an idea of system degradation as parts wear out.
Keep the wheels on the ground
Bob
showshine@aol.com
RE: Efficiency tests for pumps in operation
1)with pumps running measure flow and outlet pressure where pump outlets combine. This will probably be the difficult bit if you dont have instrumentation!
2)Using SI units multipy pressure by flow i.e
m3/s * Pa = Watts (work being done)
NB 1Pa= 1N/m2, also 1Bar = 1 x 10^5 Pa
Read off the power consumption printed on pump motors.
Calculated value for work should be about 50% of the motor power consumption allowing for inefficiency of the motors, the pumps and any losses in the pipes / manifolds. If your in this ballpark all is well!
RE: Efficiency tests for pumps in operation
It was a long time ago but i seem to remember it worked on multi pump sets but unfortunatly i can remember no more
RE: Efficiency tests for pumps in operation
tr = Head * (1 - E) / (778 * E)
E is the efficiency as a decimal
Head is in feet
tr is the temperature rise in deg F
RE: Efficiency tests for pumps in operation
but i still can't remember the name
RE: Efficiency tests for pumps in operation
RE: Efficiency tests for pumps in operation
The remaining work that doesn't go into producing head goes into heating the liquid up. Throw in a heat capacity, flowrate (which would cancel out), you should wind up with the 778 factor though I haven't worked through it. Okay, who's bored on a Sunday night
RE: Efficiency tests for pumps in operation
Pout = Q * Head * rho (where rho = density)
SHP = Pin = Pout/E = Q * Head * rho / E
Losses = SHP * 1-E = Q * Head * rho * (1-E) / E
Also losses = Q Cv dt
equating two expressions for losses:
Q Cv dt = Q * Head * rho * (1-E) / E
dt = (rho/Cv) * Head (1-E) / E
RE: Efficiency tests for pumps in operation
The definition of Head is also energy by unit mass...so
1 ft = 1 lb-ft/lb = (1/778)Btu/lb
HTH
saludos.
a.
RE: Efficiency tests for pumps in operation
HTH
Saludos.
a.
RE: Efficiency tests for pumps in operation
Yates meter...
RE: Efficiency tests for pumps in operation
RE: Efficiency tests for pumps in operation