Pumps move fluids like liquids and gases using mechanical action. There are many types of pumps that use different mechanisms and energy sources. Positive displacement pumps trap and displace a fixed volume of fluid with each cycle. Common types are reciprocating pumps like piston and plunger pumps and diaphragm pumps. Rotary pumps use rotating gears, lobes, screws, or vanes to pump fluid. Centrifugal pumps use an impeller and centrifugal force to move fluid outward, while turbine pumps combine high pressure and flexible operation.