Working of Steam-Jet Ejector

Working of Steam-Jet Ejector

A steam-jet ejector consists of an inner converging-diverging (or converging alone) nozzle through which the driving fluid (steam) is fed, and an outer, larger nozzle through which both the extracted gases or vapors and the driving fluid pass.







At the present day, Steam jet ejector is the preferred vacuum producing devices

for many applications in the petrochemical, food processing, refining, chemical-

processing and power generation industries.




The momentum of the high-speed fluid leaving the driving nozzle is partly transferred to the extracted gases or vapors, and the mixture velocity is therefore less than that of the driving fluid leaving the smaller nozzle. It is nevertheless higher than the speed of sound, and the nozzle therefore acts as a converging-diverging diffuser in which the pressure rises and the velocity decreases, passing at speed of sound through the throat.