A Pump Curve Needs Speed and Impeller Identity

Before comparing a curve with a transfer duty, identify the configuration that produced or defines it.

Read the Curve Family

KSB explains that a selection chart can contain several curves for changing parameters such as impeller diameter or rotational speed. A curve family is not one universal performance line. The relevant line must correspond to the proposed configuration.

Retain the manufacturer, pump designation, curve revision, speed and diameter or selected trim reference. Also identify the test-liquid basis and any supplier correction relevant to the actual product. A cropped image can remove exactly the labels needed to choose the right line. KSB primary engineering reference.

Illustrative Ambiguity

A hypothetical screenshot shows three head/flow lines but crops off their diameter labels. A marked duty point falls near one line. Until the selected diameter and speed are restored, that point cannot be attributed to the offered pump configuration.

The example contains no HM curve or measured result. Its lesson is document identity: ask for the complete source chart and the selected configuration. Do not redraw a convenient line and label it as supplier performance.

Keep the Selection Record Complete

Where the supplier proposes an estimate, identify its source and assumptions separately from original manufacturer data. Keep additional curves such as power, efficiency or suction requirement associated with the same selected arrangement. Their presence on another page does not prove that they use the same conditions.

Use the worksheet to preserve the complete chart and the offered configuration beside the actual system duty. This is the documentary step before numerical curve interpretation. It does not establish a universal impeller choice or permit modification of installed equipment. Relevant HM context: Processing Tank.