The Hydraulic Institute says its Pump Efficiency Prediction guideline (HI 20.3-2010) is now available in a separate, self-contained publication at The guideline presents a simple method that will help pump users predict normally attainable efficiency levels at the best efficiency point for selected types of rotodynamic pumps when the rate of flow, total head per stage, net positive suction head available, and the service conditions are known. Graphs are used extensively to portray the relationship of pump efficiency versus different parameters.

The guideline contains information that explains how surface roughness and internal pump clearances affect pump efficiency and helps users understand the power consumption and efficiency loss created by bearings, lip seals, mechanical shaft seals and shaft packing.

The guideline includes these pump types:
•    Slurry, end suction;
•    Solids-handling, end suction pumps;
•    Submersible sewage, end suction;
•    Stock, end suction;
•    Horizontal multistage, axial split, segmented ring diffuser barrel;
•    ASME B73, API end suction, end suction – small;
•    End suction – large (greater than 0.3 m3/s (5,000 gpm);
•    API double suction;
•    Double suction, general service; and
•    Vertical turbine, mixed-flow and propeller, single and multistage diffuser type.

“The data used to develop the material contained in this guideline is based on actual test results from many different rotodynamic pump manufacturers. The pump community now has a reliable, easy-to-apply method to estimate rotodynamic pump efficiency and compare attainable efficiency levels for different pump types, including factors that influence efficiency,” said Gregg Romanyshyn, technical director of HI.

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