Injector

Injector, in engineering, is a contrivance for forcing a liquid through an orifice by means of the flow of another stream of fluid through a small jet concentric with the orifice. The most ingenious is Giffard's injector for pumping water into a steam boiler by means of a jet of steam from the same boiler. Though it would at first seem impossible for the steam to overcome the opposing pressure of the water from the same boiler, the paradox disappears when the fact is considered that the steam. is condensed into water at the jet. The energy thus liberated is converted into kinetic energy of the fluid through the jet, and outflow of the boiler water is prevented.