Which positive displacement pump involves moving liquids by rotating a screw, lobes, gears, or vanes?

Which positive displacement pump involves moving liquids by rotating a screw, lobes, gears, or vanes?

• A. Reciprocating Pump
• B. Gear Pump
• C. Rotary Pump
• D. Vane Pump

Answer: (C)

Rotary pumps are positive displacement devices that move fluid by rotating components. As parts rotate, they trap fixed volumes of fluid in cavities and carry them from the suction side to the discharge side, producing a steady flow. The mechanisms mentioned—screws, lobes, gears, or vanes—are all ways to realize this rotating displacement: a screw pump uses rotating screws; a gear pump uses intermeshing gears; a vane pump uses sliding vanes; a lobe pump uses two rotating lobes to trap and move pockets of fluid. Because the action relies on continuous rotation to transfer a fixed volume with each rotation, this describes a rotary pump. In contrast, a reciprocating pump delivers fluid via back-and-forth motion of a piston or diaphragm, which is not rotating and typically produces a pulsating flow.

Rotary pumps are positive displacement devices that move fluid by rotating components. As parts rotate, they trap fixed volumes of fluid in cavities and carry them from the suction side to the discharge side, producing a steady flow. The mechanisms mentioned—screws, lobes, gears, or vanes—are all ways to realize this rotating displacement: a screw pump uses rotating screws; a gear pump uses intermeshing gears; a vane pump uses sliding vanes; a lobe pump uses two rotating lobes to trap and move pockets of fluid. Because the action relies on continuous rotation to transfer a fixed volume with each rotation, this describes a rotary pump. In contrast, a reciprocating pump delivers fluid via back-and-forth motion of a piston or diaphragm, which is not rotating and typically produces a pulsating flow.