What is a common example of a positive displacement pump?

A gear pump is a common example of a positive displacement pump because it operates by entrapping a fixed amount of fluid and forcing it through the pump's discharge port with each rotation of the gears. In a positive displacement pump, the fluid moves in discrete volumes, which makes this type of pump particularly effective for applications requiring high viscosity handling and precise flow rates.

The design of a gear pump, with its two interlocking gears, creates a sealed environment that traps the liquid and moves it mechanically, ensuring a continuous flow as the gears turn. This principle of displacement is characteristic of this pump type and highlights its reliability in various industrial and hydraulic applications.

While centrifugal pumps and rotary pumps may be used in many scenarios, they function differently. Centrifugal pumps rely on rotational energy to create a flow of liquid through the use of an impeller, making them more suited for lower viscosity fluids and applications where flow rate rather than precise fluid displacement is crucial. In contrast, rotary pumps can encompass various designs, not all of which operate on a positive displacement mechanism. Diaphragm pumps, while also classified under positive displacement, have a different operational method involving a flexible diaphragm that creates a pumping action, making them distinct from the gear mechanism used in gear pumps.