PDA

View Full Version : Define pump



Vladyman
February 3, 2017, 12:47 AM
I have a pump that connects to the users and to one tank. The idea is that when the tank has low water it will receive water, and when the tank has high water level it will provide water (during high demand).
I am using this pump
https://www.wcc.nrcs.usda.gov/ftpref/wntsc/Pump%20Curves/Bell%20and%20Gossett/1800/6x8x17L.pdf

1000 GPM, 280 ft, 125 HP, Max WP 175 psi, 1800 RPM, D 17"

However, the pump only provides 7 GPM, very low considering that is can provide 1000 GPM.
I provided this NSPH curve:
1000 GPM - 10 ft
1500 GPM - 16 ft
1800 GPM - 22 ft

I tried:
i) Constant power 125
ii)Design point. Design head 280ft, Design Flow 1000 GPM
iv) Multiple point curve
0 GPM 290 ft
1000 - 280
1500 - 250
1800 - 220

Why is the pump giving so little water?
If I close the pipe of the Tank the simulation fails unbalanced error.370

Vladyman
February 3, 2017, 01:36 AM
Solved.
The pipe before the pump had wrong diameter (very small).
One more question.

Patrick Moore
February 3, 2017, 08:14 AM
Good find. Note any pump is only going to operate where the pump curve meets the system curve and so it can often be a good idea to see when the pump is running where the head and flow are. If they are not near the design point it is often likely that something is impacting either the HGL up or downstream, or in your case if there was something causing a large headloss that pushed the pump way back on its curve. You can often find that by searching the pipe range report for pipes with high headloss. You can use the "filter tool" to select pipes that meet a certain criteria you specify in the output report.

Data filtering (click if need larger image)
371

Best to you.

Patrick