How To Digitize a Pump Curve

Centrifugal pumps are commonly used to move or transport liquids from one place to another. The type, size, and characteristics of a pump determine the volume and pressure (head) developed by a pump. The intent of this article is not to explain how a pump works and if you don't know the basics of a centrifugal pump, you need to look elsewhere.

A "pump curve" is used to describe the flow rate versus total dynamic head (TDH) developed by a centrifugal pump. Typically the pump will develop the highest head at zero flow and the maximum flow at zero head. The pump curve is used to describe the properties of the pump. Keep in mind that the pump curve is only applicable for a specific pump and is typically rated for water flow at normal conditions.

An example of a flow curve is shown below. Click on the image to view an enlarged image.

Now that we have a pump curve, what do we do with it? In order to use a pump curve in a hydraulic modeling routine, the curve must be digitized or converted into a list of Flow, Head values at various points on the curve. In order to do a reasonably accurate conversion of the curve, you need a method and that's where the flow guy comes in. While I cannot guarantee that I am the person who developed this method, I have not seen anyone else doing it this way. The method shown below is simple and easy to use.

What Is Needed