pump

A pump is a mechanical device that moves fluids by imparting energy to the fluid, creating flow and pressure. By drawing fluid into an inlet and expelling it at a higher pressure, pumps enable the transport of liquids and, in some designs, gases. Pumps are central to water supply, waste handling, manufacturing, and many engineering systems. They are typically classified by their operating principle into dynamic (or kinetic) pumps and positive-displacement pumps.

Dynamic pumps, including centrifugal, axial, and mixed-flow variants, add energy to the fluid by an impeller. The imparted velocity is converted into pressure as the fluid exits through a volute or diffuser. Positive-displacement pumps trap a fixed volume and then discharge it, making them capable of producing high pressures and delivering accurate volumes. Subtypes include gear, vane, screw, piston, diaphragm, and peristaltic pumps.

Key performance metrics include flow rate (Q), head or pressure rise (H), efficiency, required input power, and net positive suction head (NPSH). Cavitation can occur if inlet conditions allow vaporization, and some pumps require priming to fill the chamber with fluid before operation.

Common applications range from water supply, irrigation, and drainage to chemical processing, oil and gas, HVAC, and wastewater treatment. Material selection and sealing are important for chemical compatibility, temperature, and wear; maintenance focuses on bearings, seals, impellers, and casing wear.

History traces early machines such as the Archimedes screw, with modern centrifugal pumps becoming widespread in the 19th and 20th centuries. See also pumping systems and related equipment.