| 摘要 |
PURPOSE: To improve evacuating efficiency by, in a two-stage cryopump, additionally providing a throttling valve for forming a diameter-variable opening to a first stage composed of a lower baffle and an upper baffle held on an support shaft extending through the opening of the throttling valve. CONSTITUTION: A cryopump 80 for evacuating the interior of a work chamber connected to the side of an opening 28 has a low-temperature finger cooling means 34 disposed on a floor 3 of a housing 22, a first stage 44 for condensing steam, and a second stage 46 for condensing other gas. The first stage 44 includes a shroud 48 solely in thermal contact with an expansion cylinder 41 of the cold finger 34, and the opening of the shroud 48 is provided with a baffle means 54. Further, cryopump 80 further includes a flow throttling valve 82 for holding movable planar iris shutter leaves 94 by a mounting ring 86 turned by a drive gear 88. An upper baffle 104 is mounted in an upper portion 98 of shutter leaves 94 and connected to the baffle 54 via a shaft 102 so as to form a first stage 100 together with the baffle 54.
|
