| 摘要 |
<p>The present invention relates to a vacuum pumping system (18) for evacuating gas from a plurality of chambers (12, 14, 16) at different pressures. The pumping system comprises a plurality of compound vacuum pumps (20, 22), wherein each compound pump comprises a plurality of pumping mechanisms (24,26,28) connected in series between a pump inlet (30) and a pump exhaust (32) and an interstage port (34, 36) between pumping mechanisms in the series. The system is configured such that gas evacuated from one of said chambers is pumped through the interstage ports of at least two of said compound pumps.</p> |
