Vacuum system, design exhaust

The simplest designs are volume separators in which droplets of pump fluid are separated from the exhaust gas flow by the reduction in the flow speed. These separators are used in liquid ring vacuum systems. The separation can be improved by fitting swirl bodies. A mixture of saturated vapours that varies according to the operating temperature of the vacuum pump always emerges from the exhaust gas nozzle. 

This discussion will address needs, applications, performance characteristics, and design considerations for LVHV exhaust ventilation. The applications are primarily for dust control. LVHV systems can be effective for protecting workers from dust exposures and for recovering valuable process materials. The equipment, excepting the nozzles, involves technology that is the same as for large central vacuum cleaning systems. 

In the case of the exhaust plume tests, the exhaust gas must be allowed to fully expand throughout the pertinent region of interest. This test requirement places some unusual demands upon the facility s vacuum pumping system. The requirements for the pumping of a directional free-molecule flow will be discussed in this paper, and a cryopump design technique will be presented which satisfies the exhaust plume test objectives. 

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