🔍 Key Concepts

• Look closely at how many separate screw rotors are shown in the cutaway view and how they mesh together. • Compare the flow path in the illustration with how centrifugal pumps work versus how positive displacement rotary and reciprocating pumps work. • Notice the labels: "Power Rotor" and "Idler Rotor" and think about what that tells you about the pump type.

💭 Think About

• Based on the illustration, is the liquid moved outward by a spinning impeller, or is it carried along in enclosed cavities formed by screws or pistons? • Count the distinct helical elements in the rotor section—how many are there, and how does that relate to the names of the answer choices? • Which of the listed pump types would normally have a piston and cylinder arrangement with valves, and do you see that here?

✅ Before You Answer

• Count the number of rotors/screws visible in the cross‑section and match that to the names of the options. • Confirm whether there is any impeller with radial vanes (typical of centrifugal pumps) or if all you see are intermeshing helical screws. • Verify if there is any reciprocating motion and valves in the diagram; if not, rule out the pump type that depends on that action.