METHODS FOR PUMP SIZING
1. CALCULATE THE FLOW RATE.
2. CALCULATE THE FRICTION LOSS, Pf.
3. CALCULATE THE STATIC LOSS
4. CALCULATE RESIDUAL PRESSURE REQUIREMENT (Pr) FOR FURTHEST DEVICE AND CONTROL VALVE PRESSURE DROP.
5. APPLY SAFETY FACTOR TO CATER FOR UNCERTAINTY OF FRICTION LOSS
6. WHEN DRAWING SYSTEM CURVE APPLY AFFINITY LAW ONLY TO THE FRICTION COMPONENT.
7. UNDERSTAND WHETHER THE FLOW IS FIXED OR VARIES.
8. FOR FIXED FLOW RATE AND FIXED PUMP HEAD SUCH AS WATER TRANSFER FROM TANK TO TANK, USE CONSTANT SPEED PUMP WITH LEVEL SWITCH CONTROL, THUS ALLOWING THE OPERATION POINT TO FOLLOW THE SELECTED PUMP CURVE AND SYSTEM CURVE.
9. FOR VARIABLE FLOW AND HIGH FRICTION LOSS AS COMPARED TO STATIC LOSS, USE VSD AND POSITION PRESSURE SENSOR AT MOST CRITICAL FITTING.
10. CHOOSE PUMP WITH CURVE SUCH THAT SYSTEM OPERATES MOST OF THE TIME BETWEEN 80-110% BEP. NEVER OVERHEAD PUMP TOO MUCH. AVOID CAVITATION WHEN SELECTING PUMPS.
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