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  1. ojsturbo

    NPSHR Test

    Thank a lot, BigInch. Please allow my ignorance again. I wanna add once again what I think about the test procedure to make it sure. 1) A pump is running at flow(A) and speed(B) with TDH(C). 2) When the suction valve is piched down a little bit to reduce NPSH, the pump TDH will be rising a...
  2. ojsturbo

    NPSHR Test

    Thanks again, BigInch. You mean they need two suction valves at least for the test; one is near the pump impeller suction for reducing NPSH, and the other is to control the source flow rate far upstream. They do not modulate the discharge valve. I still wonder if this means the same as Artisi's...
  3. ojsturbo

    NPSHR Test

    BigInch, please allow my ignorance. What I want to know is how to keep a constant flow in the NPSHR test to get the 3% drop-off curves while piching down suction valve. For example, at an initial test point, there is one set of flow-head-NPSH at constant speed. To get a second point of reduced...
  4. ojsturbo

    NPSHR Test

    Thanks, Artisi. If they have to open the discharge valve in order to return to original flow, I do not think they can get many data points of NPSH for a constant flow rate. Do they experience some limitations on the number of points available? How about changing the static lift instead of...
  5. ojsturbo

    NPSHR Test

    In NPSHR tests, when a suction valve is piched down to reduce NPSH, the pump flow is of course reduced accordingly. How can they keep the flow unchanged ? The 3% drop-off curves are for constant flow and speed.

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