What is bowl efficiency? | Pumps and systems
What is bowl efficiency and is it different from pump efficiency?
The term bowl efficiency is specific to vertically suspended (VS) pumps. These pumps have the pumping element (bowl assembly) submerged in the liquid with an attached column pipe which conveys the liquid to the surface. Focusing on the vertically suspended pump types VS0 and V1 in pictures 1 and 2, it can be seen that there are several pumping stages (wells) that connect to the column pipe going to the surface.
Depending on the application, the length of the column tube and the number of column supports (VS1) will change. In addition, it should be noted that the V0 type has a submerged motor while the VS1 type has an above ground motor. The variability in column length, bearings and motors makes it necessary to consider only the efficiency of the bowl assembly for a proper comparison of pumping elements.
Pump efficiency is similar to bowl efficiency in that it considers the pump without the drive and is often used for cantilever and between-bearing pumps. If pump efficiency were applied to the VS1 and V0 types above the pump, the efficiency would change depending on the length of the column pipe and bearings, which is a function of the specific application. Image 3 shows a cantilever pump, and the inlet and outlet system piping will connect to the pump casing (item 1).
The measure of pump efficiency is relative to the power added to the system relative to the input and output flange and shaft input power. For more information on pump efficiency, refer to the HI standard for “Rotodynamic Pump Efficiency Test Methods (HI 40.6)” at pumps.org.
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