Pump H-Q Curve
The pumping performance of a centrifugal pump is
expressed in the form of an H-Q curve, depicting the Flow Q (e.g. in
m³/h) and the Head H (e.g. in m) of the pump.
The graph of the curve is shown dropping from top left
to bottom right with increasing rate of flow. The slope of the curve is
determined by the pump construction and particularly by the design of
the impeller.
The characteristics of the pump duty curve is the inter-dependent
relationship between capacity and head.
Each change of head effects a consequential variation in the rate of
flow.
- High rate of flow -> low head
- Low rate of flow -> high head
Though it is the frictional resistance of the installed pipe system which determines a given pump capacity, the respective pump can take up only one duty point on its curve. This duty point is the intersection of pump H-Q curve with the system H-Q curve.