| 摘要 |
PURPOSE:To improve pump performance, by a method wherein a short vane is positioned between at least either the moving vanes or the stationary vanes of a molecular pump. CONSTITUTION:An annular support 13, through which the middles of moving vanes 3 of a turbo molecular pump, and a short vane 12, protruded outwardly from the support 13 between the moving vanes 3 is provided. A short vane 14, protruded inwardly from a casing 4 between stationary vanes 4, is provided. Thus, a difference in a distance between the vanes is decreased, and when the number of vanes is set to an optimum value, a distance between the vanes is distributed to an optimum value or a value in the vicinity of the optimum value, and this enables improvement of pump performance.
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