NCCER Millwright Practice Exam

What describes a gear pump that uses two identical gears meshed together?

1. Centrifugal gear pump

2. Single gear pump

3. Internal gear pump

4. External gear pump

The correct answer is: External gear pump

A gear pump that utilizes two identical gears meshed together is best described as an external gear pump. In this configuration, the two gears rotate in opposite directions, creating a pumping action as fluid is trapped between the gear teeth and transferred from the inlet to the outlet as the gears turn. External gear pumps are commonly used in hydraulic systems because they are efficient at moving fluids and can handle various viscosity levels. This design also allows for a straightforward construction, which is advantageous in many applications. In contrast, centrifugal gear pumps do not exist as a category, as centrifugal pumps operate on a different principle entirely, relying on rotational energy to move fluid rather than using meshed gears. Single gear pumps utilize only one gear, which does not create the same meshed action and is less efficient for fluid transfer. Internal gear pumps involve a different configuration where one gear is located within another, creating a different mechanical interaction and flow pattern compared to external gear pumps.