Which type of pump rotates gears with teeth to move liquid?

A gear pump is designed to move liquid by using the mechanical action of interlocking gears. The teeth of the gears create a vacuum that draws the liquid into the pump, and as the gears rotate, they displace the liquid and push it out through the discharge. This design allows for continuous flow and provides a relatively constant pressure, making gear pumps suitable for various applications where precise flow and pressure are required.

In contrast, centrifugal pumps rely on the rotational energy of an impeller to move liquid, while piston pumps use the back-and-forth motion of a piston to create pressure and move fluid. Diaphragm pumps operate by flexing a diaphragm to create suction and discharge, which is different from the gear mechanism. Thus, the unique operation of gear pumps, characterized by their gear-driven movement of liquid, clearly identifies them as the correct response to the question.