To reduce the tendency for pump cavitation when the intake is lower than the pump, which options are effective?

To reduce the tendency for pump cavitation when the intake is lower than the pump, effective strategies typically involve managing the pressure and flow conditions at the pump's inlet.

Strategies that could be part of your options may include lowering the pump's operating speed, which reduces the velocity of the fluid entering the pump and helps prevent cavitation. Increasing the diameter of the suction pipe is another method, as a larger pipe can decrease the velocity and subsequently the pressure drop, minimizing cavitation risks. Finally, installing a pump with an appropriate NPSH (Net Positive Suction Head) margin ensures that the pump has sufficient pressure at the inlet to avoid cavitation.

The correct answer suggests that options II and III are effective methods, which likely include options about increasing suction pipe diameter and ensuring adequate NPSH. Such practices directly address the conditions leading to cavitation by modifying the flow and pressure characteristics at the pump's intake, thus enhancing overall pump performance and longevity.