| 摘要 |
<p>PURPOSE:To obtain a small-sized vacuum pump which can continuously operate from the atmospheric pressure to a vacuum state by installing an axial flow compression pump stage and a screw compression pump stage on a suction port side and installing a circumferential flow compression pump stage on an exhaust port side. CONSTITUTION:A rotary shaft 1 penetrates through a housing 2 having a suction port 2A and an exhaust port 2B and is rotatably supported through a bearing 7, and driven by a motor 10. In this case, an axial flow compression pump stage 15, screw compression pump stage 14, and a circumferential flow compression pump stage 13 are connected in succession between the suction port 2A and the exhaust port 2B. In the transient state in the initial stage of the pump operation, the inside of the pump is set into the atmospheric pressure state, and the gas is made into viscous flow, and each pump stage 15, 14 is allowed to act as compressor. In the stationary state, sealing action is obtained in each pump stage 15, 14 by forming the gas into intermediate flow or molecular flow, and the sufficiently low final pressure can be obtained with a small number of stages.</p> |
