How to deal with water pump cavitation
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I would like to ask everyone: A new water pump has been installed in the factory, as shown in the diagram. The inlet undergoes a two-stage reduction in diameter from DN350 to DN125, while the outlet has its diameter reduced to DN300. Rated flow rate is 240 m3/h, and head is 50 m. After starting, a whistling sound was heard; an inspection revealed cavitation. I would like to ask everyone: for an installation method like the one shown in the diagram, what measures can be taken to prevent cavitation? Thank you!
The diameter reduction is too much; the pump inlet was not chosen appropriately
The pipeline supports at the entrances and exits are not properly installed; check whether the design drawings match the actual installation. The eccentric size of the inlet fitting seems to be incorrect; by checking for symptoms of cavitation, flow fluctuations and pipeline vibrations can be identified. If cavitation occurs on the impeller after it has been running for a while, pitted areas will form. After performing the above steps and confirming cavitation, the inlet pressure can be increased, the inducement ratio can be raised, or the pump type can be changed to reduce the pump speed.
Thank you for your reply. Could you please provide further suggestions? 1. How to modify the imported eccentric reducer? 2. How to increase inlet pressure? 2. The inlet diameter of the pump cannot be modified; currently, the manufacturer suggests increasing the diameter of the impeller and reducing the speed (using an inverter-driven motor) to maintain the same flow rate. Is it feasible?