| 摘要 |
<p>A differential pumping seal apparatus includes a differential pumping seal for sealing a first space and a second space from each other in a non-contact manner, and a back up seal mechanism for sealing the first space and the second space from each other in a contact manner. The back up seal mechanism is operated to seal the first space and the second space from each other only when the differential pumping seal is stopped or while operation of said differential pumping seal is stopped. <IMAGE></p> |
