Which two types of centrifugal pumps are described?

• A. Single-stage and Two-stage
• B. Three-stage and Four-stage
• C. Axial flow and Radial flow
• D. Inline and End-suction

Answer: (A)

Centrifugal pumps are often described by the number of stages (impellers) they have because that determines how much head they can develop. A single-stage pump has one impeller, suitable for lower head and higher flow. A two-stage pump places two impellers in series, increasing the head available while keeping a similar flow. This pairing—one stage and two stages—is the basic way these pumps are categorized by the number of stages.

Other terms describe different aspects: three-stage or four-stage pumps exist but extend the same idea to more stages; axial flow versus radial flow refers to the direction of flow through the impeller, not the number of stages; inline versus end-suction relates to how the pump is installed or oriented, not the stage count.