| 摘要 |
PURPOSE:To obtain a cryopump whose gas discharge speed is variable, by providing a shutter means which may change the exposed area of a second panel for absorbing and trapping a low boiling point component, after a high boiling point component is absorbed and trapped from gas to be discharged by means of a baffle. CONSTITUTION:A shutter composed of a foldable thin film is secured at one end to a supporter 8 part and at the other end to a support 12 so that it is attached openably. A magnet 13 at the forward end of a support 12 is moved together with the shutter in association with the movement of a magnet 18 driven by a motor 19. Accordingly, the shutter 14 passes through a baffle 6 so that it may open and close its surface for exhaust gas such as N2, O2 or the like which is absorbed and trapped by a second panel 7. Further, since the shutter 14 is located downstream side of the baffle 6 in the direction of gas flow, no moisture and carbon oxide gas or the like are condensed on the shutter. Accordingly, it is possible to change the discharge speed satisfactorily without the rotation being stopped. Further, it is possible to prevent moisture and carbon oxide gas from being hindered in discharge to the baffle 6 even when the shutter 14 is fully closed.
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