Pump curve and its application
Centrifugal pump characteristic curve is a group of curve that measured by experiment Q, H, N, η data. This graph is provided by pump manufacturers, for the using department reference when choosing pump and operating.
characteristic curve
Different types pump characteristic curve is also different, but all has the following three curves:
(1) H-Q line shows the pressure head and the flow relations;
(2) N-Q line shows the pump shaft power and flow relations;
(3) η-Q line shows pump efficiency and flow relations;
(4) pump characteristic curve is measured in a certain rotating speed, so characteristics curve graph indicating rotating n value.
Centrifugal pump characteristic curve efficiency highest point is the design point, pump works in this point corresponding pressure head and flow is the most economic. Centrifugal pump nameplate marked performance parameters are maximum efficiency point operating condition parameters.
Centrifugal pump performance curve can be used as basis of the pump selection. After confirm pump type, then according to flow and pressure head to choose pump.
Example 2-2 using water to measure centrifugal pump main property parameter. Experiment measured flow is 10m3/h, pump outlet pressure gauge reading is 0.17 MPa (table press), the entrance vacuum gauge reading is -0.021 MPa, shaft power is 1.07 KW, motor speed is 2900r/min, the vertical distance of vacuum meter pressure measuring point and pressure gauge pressure measuring point is 0.2 m. Try to calculate the head and efficiency under this experimental point.
The main performance parameters include n, flow Q and head H, shaft power N and efficiency. Direct measured parameters are
rotating speed n=2900r/min
flow Q＝10m3/h=0.00278m3/s
shaft power N＝1.07KW
Head and efficiency need to calculate.
calculate head, ie
known
so
