A pump uses pressure differentials to transport various liquids and gases from one place to another. There are two major types of pump: positive displacement pumps, which force a specific volume of fluid through a pressurized discharge channel, and rotodynamic pumps, which use rotating blades to accelerate fluid and convert its kinetic energy into pressure. Positive displacement pumps can provide continuous material flow even at different pressures, and they are used in chemical processing, beverage and liquid production, and the pharmaceutical industry. Rotodynamic, or centrifugal, pumps are generally more powerful and can be found in a wide variety of applications, including irrigation networks and sewage systems.