Which pump uses two gears with teeth in opposing directions to move the liquid around the casing to the outlet?

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

Answer: (B)

Two gears with teeth that mesh and rotate in opposite directions inside a sealed casing create a positive-displacement pumping action. As they turn, each gear tooth traps a fixed amount of liquid between the teeth and the housing. These trapped pockets are carried around the outer circumference from the suction side to the discharge side, and the tight fit between gear teeth and casing prevents backflow. When the pockets reach the outlet, the liquid is expelled, producing a steady, high-pressure flow. This mechanism is characteristic of gear pumps, which are especially effective for viscous liquids. Other pump types use different methods—screws, vanes, or pistons—so they don’t rely on two intermeshing gears moving fluid around the casing in opposite directions.