| 摘要 |
<p>A vacuum pumping system for use with a process chamber (1), comprising a first vacuum pump (2) whose inlet is adapted for communication via a first line with a chamber outlet and a further vacuum pump (3) whose inlet is adapted for communication via a second line (4) with a first pump outlet, wherein a third line (7) containing a throttle valve means (8) is linked to the first and to the second lines in parallel to the first vacuum pump (2) to enable variable amounts of gas to flow through the valve (8) from the second line (4) to the first line depending on the position of the valve member (8). <IMAGE></p> |
