Maintenance Technician Practice Test 2025 - Free Maintenance Technician Practice Questions and Prep Guide

A positive displacement pump operates by trapping a fixed amount of fluid and forcing it into the discharge pipe. All the types of pumps listed fall under the category of positive displacement pumps, which is why the correct response is that "all of the above" are included.

Reciprocating pumps function by using a piston or diaphragm that moves back and forth to create a change in volume inside a chamber, thereby drawing in fluid and subsequently displacing it.

Gear pumps utilize the meshing of gears to move fluid. As the gears turn, they trap fluid between the gear teeth and the pump casing, creating pressure that forces the fluid to flow to the discharge side.

Screw pumps are designed with helical screws that, when rotated, move the fluid along the screw's axis. This consistent movement and change in volume make them effective in fluid transfer and pressure generation.

Together, all these mechanisms emphasize the principle of positive displacement, where the pump displacement is constant per cycle and depends on its design rather than fluid properties. Hence, they are all classified as positive displacement pumps.