Reading Centrifugal Pump Curves（阅读离心泵曲线）.pdf

PUBLISHED BY THE NATIONAL ENVIRONMENTAL SERVICES CENTER Reading Centrifugal Pump Curves By Zane Satterfield, P. E., NESC Engineering Scientist Summary Reading and understanding centrifugal pump curves is key to proper pump selection, and to their reliable and efficient operation. This Tech Brief examines how pump curves can provide data about a pump’s abili- ty to produce flow against certain head, shows how to read a typical centrifugal pump curve, and provides information about pump efficiency and brake horsepower. Pumps are the workhorses of any drinking water dis- Total Head / Total Dynamic Head—the total height tribution or wastewater collection system. They operate difference (total static head) plus friction losses and de- 24 hours a day, 365 days a year getting water to homes mand pressure from nozzles etc. (total discharge head) and business, and removing wastewater from them. A = total dynamic head. correctly sized pump will work efficiently for many years, saving a system money and energy. An incorrectly sized Capacity/Flow—the rate of liquid flow that can be car- pump can fail if it’s too small or result in unnecessary ried, typically measured in gallons per minute (gpm). expense if it’s too big. Pump curves provide a way to see Net Positive Suction Head—how much suction lift a the correct size a pump should be for specific conditions. pump can achieve by creating a partial vacuum. At- mospheric pressure then pushes liquid into pump. A Pump Terminology method of calculating if the pump will work or not. Before discussing specific details, it helps to understand typical terms associated with pump curves: