CWEA Mechanical Technologist II Practice Test

The primary design feature of an external gear pump is two intermeshing gears. This type of pump operates by having two gears that rotate in opposite directions, drawing fluid into the pump chamber and pushing it out. The design relies on the precise meshing of the gear teeth to create a seal that traps the fluid and moves it along the pump's casing.

External gear pumps are known for their efficiency in transferring fluids, especially viscous liquids, due to this design, which allows for a consistent flow rate. The intermeshing gears also help reduce the pulsation of flow, making them suitable for various applications in hydraulic systems and other fluid management processes. Overall, this characteristic of using two intermeshing gears is what makes external gear pumps distinct from other pump designs, such as those that might use helical rotors or lobes.