Flow recirculation: Why does it happen and how can you stop it

Switching to a VFD can benefit nearly every centrifugal pump service suffering from inlet recirculation.

By Andrew Sloley

Suction recirculation can undermine operation of a centrifugal pump at low flows. The pump’s suction specific speed and suction energy can provide insights about potential difficulties. Variable frequency drives (VFDs) frequently can provide a solution.

Fixing suction recirculation problems often costs money. Typically, getting the funding requires convincing the holder of the purse strings of what’s the real cause of a problem.

Many people have trouble grasping the idea that flow can go backward within a centrifugal pump. Over the years, I’ve often struggled to find a fundamentally correct but simple explanation.

Read the whole story on Chemical Processing

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