Question:
What is recirculation, and what are some of the end results of recirculation?
Answer:
Recirculation is the reversal of part of the flow back through the pump impeller and occurs when the pump operates at a rate lower than best efficiency point. Recirculation can occur at both the suction and discharge of the impeller.
Recirculation warning signs include a random loud crackling noise with high intensity knocks.
What’s the result of recirculation?
Cavitation damage at:
- The underside of the impeller blades
- Guide vanes in pump suction connection (if fitted)
- Cutwater or diffuser vanes
- Vibration and mechanical damage such as bearing and seal failure.
As with cavitation due to low net positive suction head the overall potential impact
is increased maintenance and downtime of the pump – which means greater costs.
Article courtesy of Kelair Pumps Australia – When Pump Knowledge Matters.
For more information phone 1300 789 466 or visit www.kelairpumps.com.au.
