What type of pumps are piston, diaphragm, and gear pumps classified as?

Piston, diaphragm, and gear pumps are classified as positive displacement pumps. This classification is based on the way these pumps operate. Positive displacement pumps work by trapping a fixed amount of fluid and then forcing (or displacing) that volume into the discharge line. This characteristic enables them to maintain a consistent flow rate regardless of the pressure, making them particularly effective for applications where precise delivery of liquid is required, such as in pesticide application.

In contrast, centrifugal pumps, which are not the correct classification here, operate differently by using a rotating impeller to impart velocity to the fluid, converting that velocity into flow. Therefore, the flow rate for centrifugal pumps varies depending on the system's pressure. Pressure pumps and flow pumps are also not specific classifications for piston, diaphragm, and gear pumps, as these terms broadly refer to pumps that generate pressure or manipulate flow without defining their operational principles as positive displacement units do. Thus, the definitive classification is positive displacement pumps, accurately reflecting the operational mechanism of piston, diaphragm, and gear pumps.