Gas entrainment can turn an otherwise stable liquid feed system into a frustrating troubleshooting problem. The effect depends strongly on pump type, suction conditions, compressibility, and how the system is controlled.
The pump no longer sees an incompressible fluid
When gas enters a pumping chamber, part of the pump stroke can be spent compressing the gas rather than moving liquid. At very low flow rates, even a small gas volume can become significant relative to displacement per stroke.
Look upstream before blaming the pump
Entrained gas can originate from dissolved gas coming out of solution, suction leaks, flashing, inadequate NPSH margin, or process conditions in the feed vessel.
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