ABSTRACT

Kinetic propellant pumps are vacuum devices that operate with various fluids to obtain pumping effects. Vacuum jet pumps are the transfer kinetic propellant pumps that operate with higher-pressure fluids as pumping media. Vapor jet ejector pumps are propellant transfer devices used for pumping vacuum systems to rough vacuum particularly in chemical industrial plants and distillation, degassing steel, and recrystallization processes. Ejector pumps are constructed with Laval nozzles and tapered mixing chambers, while they operate at high heating power. The chapter illustrates the determination of the ideal pumping speed and quality coefficient of diffusion pumps. Diffusion pumps cannot work against the atmospheric pressure. The ultimate pressure of vacuum systems produced by diffusion pumps depends on the pump constructions, properties of the pump fluid, additional accessories, and sealing techniques of vacuum systems. Cold traps are vacuum components employed for the reduction of vacuum contamination. Most metal cold traps are fully welded constructions that can be cleaned by thermal heating.