| 摘要 |
PURPOSE:To improve the max. compression rate and reduce the gas discharge rate and obtain a turbomolecular pump which is provided with a simple structure and has a high vacuum degree by installing a means for cooling stator blades below 0 deg.C, in the captioned device equipped with the stator blades and rotary blades. CONSTITUTION:In a turbomolecular pump, rotary blades 1 and stator blades 2 are arranged in plural stages alternately. The fixed blade 2 is fixed onto a trunk 3, and the rotary blade 1 is fixed onto a rotor 4 having a symmetrical form in the axial direction. A fixed shaft 6 concentric with the rotor 4 is arranged oppositely to the rotor 4, and a rotor driving motor 7 and a magnetic bearing 8 are arranged on the opposed surface. In this case, a trunk pipe 11 is installed onto the outer periphery of the trunk 3, and one edge of the trunk pipe 11 is connected with a liquid nitrogen tank. Further, a heat insulating material 17 is installed so as to cover the trunk 3 and the trunk pipe 11. Further, a cooling mechanism is constituted of the trunk pipe 3 and the heat insulating material 17, and the fixed blade 2 is cooled below 0 deg.C.
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