Which types of pumps are categorized as positive displacement pumps?

Positive displacement pumps operate by entrapping a fixed amount of fluid and forcing it into the discharge pipe. They achieve this by using mechanical means that create a reduction in pressure, allowing the fluid to enter the pump and be pushed out with each cycle.

Reciprocating and rotary pumps are both significant types of positive displacement pumps. Reciprocating pumps achieve fluid movement through linear motion, typically utilizing pistons or diaphragms that create a back-and-forth motion. This action draws fluid into a chamber and then expels it with each stroke. On the other hand, rotary pumps move fluid by using rotational devices such as gears or lobes, continuously drawing in and displacing fluid with each rotation.

This classification is essential in understanding pump operation and applications in various fluid transfer scenarios. The other types mentioned, including submersible, centrifugal, turbine, and propeller pumps, do not function as positive displacement pumps; rather, they rely on kinetic energy and pressure differentials to move fluid.