| 摘要 |
PURPOSE:To increase exhaust gas speed and improve the efficiency of the pump by a method wherein the blade angles of the moving and stationary blades of several stages at the suction side are designed so as to be larger than a single stage design value in the multi-stage turbo molecular pump. CONSTITUTION:In case the blade angles of several (1-3) stages of the suction side are selected so as to be 1.2-1.33 times of the single stage designing value in order to maximize the efficiencies of the blade angle and the exhaust gas speed under extending the blade row performance of the turbo molecular pump to the multi-stage blade wheels, the maximum exhaust gas speed efficiency may be increased by 4-8% compared with the pump in which the blade angle is selected based on the performance of conventional signal stage blade row. According to this method, the exhaust gas speed may be increased by selecting the blade angle (35-45 deg. at the suction side) in which the exhaust gas speed is maximized as compared with the conventional turbo molecular pump.
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