The working fluids of mechanical vacuum pump and steam flow vacuum pump are water, mercury and oil used in water ring pump, mechanical pump, molecular pump, jet pump and diffusion pump. The steam jet pump and diffusion pump rely on the working liquid vapor for jet or diffusion pumping.
Therefore, at the working temperature of the pump boiler, it is expected that the working fluid has sufficient vapor pressure. At normal temperature, oil vapor may diffuse the whole evacuated vessel and become the limiting factor of limiting vacuum. Therefore, it is hoped that the working fluid has low saturated vapor pressure at normal temperature. In addition to certain requirements for its vapor pressure characteristics, good thermal stability, oxidation resistance and moderate fluidity at room temperature are also required by Yan gas jet pump and diffusion pump. Vacuum pump oil can be roughly divided into five categories: petroleum hydrocarbon, cool, silicone oil, halogenated carbon hydride and ether.
Getters are generally divided into evapotranspiration type and non evapotranspiration type. Evapotranspiration type is sometimes also called diffusion type or flash burning type, such as calcium, magnesium, silver, barium, etc., among which barium is the most commonly used. Non evapotranspiration type is sometimes called coating type or volume type, such as Cuo, Qin, mu, etc., in which CuO is the main component of commonly used getters. In recent years, the evaporable nitrogen doped getters, non digestible chromium aluminum and chromium graphite getters have excellent gettering properties.
Water Ring Vacuum Pump
Dry Scroll Vacuum Pump
industrial vacuum pumps,vacuum furnaces
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