Parrallel Vertical Turbine Pumps 1

[cfordyce]

Why , if two 1250 USGPM pumps are in parallel, is the output flow not 2 X 1250 = 2500 USGPM ? I realize that the actual pump output relies on the head pressure according to a chart but is this the only reason that the output is not close to 2500 USGPM? Someone told me that the output would still be 1250 USGPM? I cant see this.

CAF

 

[electricpete]

If you can locate the head corresponding to your operating condition on a single-pump curve, your flow should be twice as much.

The pump curve represents one equation in two unknowns (flow and dp). If you get one more piece of information concerning flow and/or dp, that is all you need to establish the operating point. That piece of information could be system resistance, or known pump flow, or known pump dp.

The pump curve will apply regardless of what is connected externally to the pump, as long as we use the dp accross and flow thru that pump.

 

[electricpete]

I suspect you are already aware of what I've told you, but I'd like to add one more thing.

If one pump is known to deliver 1250gpm when connected to a given system, then two pumps will not deliver 2500gpm when connected to the same system. The combined flow-rate through the same system causes a higher dp which will push each pump to the left on their curve.

 

[stressriser]

But,
I believe that if the pipe sizing is done correctly, and made large enough to accomodate the increase in flow, the discharge quantity should increase.

This would be the answer to your question, your piping is not big enough.

right?