2009-06 Jet pumps, also referred to as ejectors, are devices for the conveyance, compression or mixing of gases, vapours, liquids or solids in which a gaseous or liquid medium serves as the motive force. They operate by the conversion of pressure energy into velocity in suitable nozzles. They are "pumps without moving parts."
The basic principle of jet pumps consists in the liquid or gas jet being emitted by a nozzle at high speed entraining and accelerating the surrounding liquid, gas or solid matter. The result of this action is a mixture of the driving and entrained (sucked) fluids, the velocity of which is reduced and the pressure increased in a second nozzle.