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Steam Jet Ejectors


Steam jet ejectors are the simplest and most reliable form of vacuum producing pumps or compressors. As they have no moving parts, ejectors can provide many years of trouble-free operation. Their simplicity allows them to be manufactured from almost any material that can be machined or welded.


The operation of steam ejectors is based upon the mass-velocity (venturi) principle. The steam propellant expands while traveling through a divergent nozzle, converting pressure energy into velocity energy. At the nozzle discharge, the now high-velocity steam flows through an air chamber where it comes into contact with and entrains the process vapors to be evacuated. With this contact, the steam imparts velocity energy to the process and is decelerated. The total mass of process gases and steam enters the convergent-divergent diffuser, where velocity energy is converted into pressure. A steam ejector can therefore be considered a thermodynamic pump.

Unique Systems ejectors are designed and manufactured in compliance with HEI Standards. They are available in single- or multi-stage arrangements and can be operated with a wide variety of motive fluids. For corrosive applications, special designs and materials of construction are available.


Ejector Stages – Vacuum Range Chart

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