How does a steam ejector work for vacuum generation?

A steam ejector uses high-pressure motive steam passing through a converging-diverging nozzle, creating supersonic flow and low pressure that entrains the suction gas. The combined stream is compressed in the diffuser section where kinetic energy converts to pressure. Key parameters: motive steam pressure and flow, suction pressure, and discharge pressure. Staging (2-6 ejectors in series with intercondensers) achieves deep vacuum. Advantages: no moving parts, handles corrosive gases, and reliable. Disadvantages: steam consumption, limited turndown.