| 摘要 |
<p>The device has a motor (1) driving a ROOTS type mechanical dry pump (2) with four-stages (5-8) comprising suction sides (5c-8c) and outlets (5d-8d). Inter-staged pipelines (9-11) connect the outlets (5d-7d) to the sides (6c-8c), respectively. Bypass lines (12, 13) are arranged between the side (5c) and the pipeline (9) and between the pipelines (9, 10), respectively. Bypass lines (14, 15) are arranged between the pipelines (10, 11) and between the pipeline (11) and the outlet (8d), respectively. Valves (16-19) are inserted in the pipeline (9, 11) and in the bypass lines (13, 15). An independent claim is also included for a method for vacuum pumping by a multi-staged mechanical dry pump.</p> |
