Pumps are used to transfer and distribute liquids and can be broadly classified into two main categories: positive displacement pumps and dynamic pumps. Positive displacement pumps displace a fixed volume of fluid with each cycle of operation, resulting in a fixed flow rate. Dynamic pumps impart a tangential force to accelerate and increase the pressure of a fluid using rotating impellers. Common types of positive displacement pumps include piston pumps, diaphragm pumps, gear pumps, and screw pumps. Centrifugal pumps, propeller pumps, and turbine pumps are examples of dynamic pumps.