The butterfly valves were not able to open completely to varying extents between the two pumps. The rearranged valves on the discharge allowed them both to open fully and the pumps now operate nearly identically.
Lessons learned: make sure that valves can operate completely, design the suction...
We pulled the pump today. No obstructions, nothing apparently out of place.
The suction piping is a bit different between the two pumps, but my most recent theory is that the butterfly valves on the discharge lines are mated directly to the silent check valves. The butterfly valves are...
Thanks, ashtree.
The pumps were ordered with a non-witnessed test.
The "Performance test results" included serial number and tester name as well as tabular data along with the resulting curve. Each pump has its own unique test result...two differeent S/N.
Thanks, SandCounter.
These are Flowserve 12EQH (100 hp, AC drivers at 1770 RPM) with 9.25" impellers. Application is for potable water service. The branch on the north line is a pressure relief valve. No leak through.
Thanks for the idea that maybe something happened to an impeller on...
bimr, yes the gray pipe on the right is the suction piping. It is 14" diameter. The discharge piping on the left is 12"
There is a mag meter (tube) in a vault on the suction side, out of view to the lower right.
There is an isolation valve on each side of the meter, but no isolation valves on...
Flow is from right to left in the plan sheet above. 14" suction pipe on the right side from a ground level tank (about 40' of pipe; NPSHa calculates to about 1.6xNPSHr at low water level), 14" tee and elbow, 20" diameter cans with 14" suction flanges, 8' vertically from suction flange to 12"...
Sorry - very incomplete original post.
Two vertical turbine can pumps pulling water out of a ground level tank.
Common suction line out of tank to manifold.
Only one pump operates at a time - duty/standby
Each pump during their respective tests during startup, on the same gauge (moved from one...
Please help me understand flows in a newly installed pump station. Two booster pumps that came with NW factory tests have materially identical performance curves, yet in practice, they produce identical discharge head, but with 7% difference in flow. How theoretically or practically is that...
What kindof adhesion numbers indicate a satisfactory candidate for top-coating? We have a steel tank with a 40 y.o. lead paint on the exterior that was topcoated 18 years ago with a Macropoxy 920 primer and Corothane II Urethane. The more recent topcoat is showing localized spots of...
We don't shoot for a certain number. We go for what looks to be spatially representative and hydraulically unique situations seem to dominate, with only a few spread throughout the 'heart' of the network. I'd say for a rough guess that we request tests on only 2-5% of the system's hydrants...
Thanks, bimr. Yes, I've studied PP813-TN lately. I'm not suggesting that the Poisson effect doesn't apply to buried pipelines, I'm looking for a specific mention of how skin friction effects (affects? I'm never quite sure) the pullout results of the Poisson effect. In the case of a buried...
rconner, do you happen to have links to the presentation and/or white paper from that conference? I haven't yet had a call back from Performance Pipe engineering to get their take on this question that I haven't seen addressed in any documentation. I would be interested in seeing what research...
FYI - I just spoke to a 30-yr veteran engineer in HDPE and he says that he's never seen pullout due to Poisson effect in a buried application. Pullout due to not letting the pipe come to thermal equilibrium, or not letting it relax after a pull, yes, but no on Poisson's.
