If there is no positive head pressure on the intake or suction side of a centrifugal pump, what type of pump must be used?

When dealing with centrifugal pumps, having adequate head pressure on the intake or suction side is critical for their optimal operation. If there is no positive head pressure, it indicates that the pump will struggle to lift the water, leading to issues like cavitation or failure to prime properly.

The correct answer is the vertical turbine pump. This type of pump is specifically designed for situations where the water source is below the pump, allowing it to perform efficiently even in applications with low or no positive suction head. Vertical turbine pumps can draw water from deep wells or other sources that are situated below the pump, utilizing a series of impellers mounted on a shaft to lift water effectively.

In contrast, while split-case, in-line, and horizontal end suction pumps have their advantages, they typically require some degree of positive head pressure to function effectively. These types of pumps are not designed for situations where they might perform without adequate suction pressure, making a vertical turbine pump the optimal choice in such scenarios.