BHP 800.0 600.0 400.0 200.0 250.0 - . . . - - HU - . - . M HI 11 1.0 225.0 0.9 200.0 0.8 175.0 0.7 --- 150.0 0.6 Pump He

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Bhp 800 0 600 0 400 0 200 0 250 0 Hu M Hi 11 1 0 225 0 0 9 200 0 0 8 175 0 0 7 150 0 0 6 Pump He 1 (135.7 KiB) Viewed 27 times

BHP 800.0 600.0 400.0 200.0 250.0 - . . . - - HU - . - . M HI 11 1.0 225.0 0.9 200.0 0.8 175.0 0.7 --- 150.0 0.6 Pump Head (ft) & NPSHR (ft) 125.0 0.5 Efficiency 100.0 0.4 75.0 0.3 50.0 0.2 25.0 0.1 1 0.0 0.04 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 Discharge (gpm) Figure 4.2 Performance curve for a pump with an impellor diameter of 15.75-in operating at 1750 rpm. The solid black line represents pump performance curve, the solid grey line represents system curve, the dashed line represents the efficiency curve (read from right vertical axis), the dotted line represents NPSH, and the dash-dot line represents the BHP. 2. Identify the pump Operating Point on the graph above. What are the values for Q and H corresponding to this point? Also list the pump efficiency, NPSH, and BHP associated with the pump operating point? 3. Identify the Best Efficiency Point (BEP) for this pump. What is the flowrate at this point? 4. To be a good selection, the pump operating point should be 60% - 120% of the BEP flowrate. Does this pump meet that criteria? 5. Calculate the net positive suction head available (NPSH) for the system shown in Figure 4-1. The design flow rate is 3,600 gpm. Assume minor losses of one rounded entrance, and one 90- deg bend (cast/forged) and T = 100° F.