Abstract
vacuum (industrial gases). A vacuum, as used in industry, must be considered as an atmosphere or gas with special inert properties. Industrial vacuum for process uses is almost always what is called “very high vacua,” that is, in the range of 10-7-10-3 torr (10-3-10-7 mm Hg). At least two vacuum pumps in series are required to reach such low-vacuum conditions. Vacua for such purposes as electron beam welding or the vacuum melting of steel are at the high-pressure end of this range, but vacuum tubes, including x-ray tubes and oscilloscope tubes, must maintain a vacuum of at least 10-6 torr if they are to function properly. A wide range of metals react rapidly with oxygen at temperatures above 1000°F (538°C) and must be melted under vacuum conditions. Such metals include titanium, beryllium, zirconium, all the refractory metals, and the semiconductors such as silicon and germanium.
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© 1984 Chapman and Hall
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Tver, D.F., Bolz, R.W. (1984). V. In: Encyclopedic Dictionary of Industrial Technology. Chapman and Hall Advanced Industrial Technology Series. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-9674-5_22
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DOI: https://doi.org/10.1007/978-1-4615-9674-5_22
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