Power in Parallel Pumping 1

[impeller1]

Good day All,

A question here..I have 6 vertical pumps in parallel. Now, all 6 were fitted with slightly larger impellers. With this upgrade, their BHP's have gone up to around 600 horsepower. From the attached sketch you can see the arrangement. All 6 discharge into a large 42" header which splits into 2. The header then goes to a bank of filters entering on either side. All the pumps, with the exception of one, are operating at around 595 horsepower with a discharge pressure of 82 psi. Pump C, from the sketch, is operating at 615 horsepower with a discharge pressure of 86 psi. All 6 pumps were sent at the same shop, and all 6 had more or less the same repair work done to it and fitted with the same sized impellers and suction casings. Can anyone explain why this pump is drawing more power? I included the sketch because I'm not sure if its position on the header has anything to do with it??

Thanks!

 

[Artisi]

Why is pump C running at higher pressure - well that's the $64 question. At least the OP now understands why power increases as flow reduces and can look for the increase in pressure.

 

[QualityTime]

Make readings for flow and TDH and plot the curve and compare it to the catalogue curve for each pump. Also check your power factor correction capacitors