Understanding Pump Curves
The Head - Capacity Characteristic
The graph below shows us the Head Capacity Characteristic for a centrifugal pump. The black curve line reveals what volume of liquid (bottom GPM scale) will be delivered by the pump against various system resistance conditions (left hand ft Scale).
For all centrifugal pumps, when plotted in a format like the graph above, the overall shape of the plotted data always becomes a curved line because for all centrifugal pumps with close to stable curves the flow rate increases as system resistance decreases.
There are two other important pieces of information contained on the graph:
The 7" (seven inches) located at the far left side and just on top of the curve, informs us that this performance curve is for an impeller trimmed to a 7 inch diameter.
The "3550" located at the top right hand corner of the graph tells us that this performance is delivered by the pump when the impeller is rotated at a constant speed of 3550 rpm, (revolutions per minute) by the prime mover (electric motor, engine, etc.).
Follow the links below to pages focusing on other types of information provided in the Pump Characteristic and more, including graphs and explanations.
