Which is a part of a centrifugal pump?

• A. Valve
• B. Rod
• C. Piston
• D. Impeller

Answer: (D)

In centrifugal pumps, the key element that does the work is the impeller. As it spins, the blades fling fluid outward, turning rotational energy into kinetic energy and then into pressure energy as the flow is directed by the pump housing. This energy transfer from the rotating impeller to the fluid creates the flow and pressure the pump delivers. Without the impeller, there’s no mechanism to impart energy to the fluid, so pumping wouldn’t occur. A valve controls flow, a rod isn’t the energy-transfer component, and a piston is used in different pump types (positive-displacement) rather than in centrifugal pumps.