| 摘要 |
PURPOSE:To increase the activity rate of an oil diffusing pump and to prevent occurrence of ''oil back'' through provision of a liquid nitrogen cooling mechanism and a refrigerator cooling mechanism. CONSTITUTION:In an oil diffusing pump 1 connected to a vacuum chamber 4 via a pipe 8 and a valve 9, there is provided liquid nitrogen baffle 2 for a liquid nitrogen cooling mechanism. Further, a refrigerator baffle 10 for a refrigerator cooling mechanism is also provided in the pump 1. The baffle 2 is supplied with liquid nitrogen via a pipe 8, while the baffle 10 is connected to a refrigerator 11 via the pipe 8. Therefore, evacuation can be performed by use of the liquid nitrogen cooling mechanism when an operator is present and by use of the refrigerator cooling mechanism when the operator is not present. Further, since evacuation can be achieved to some extent by use of the refrigerator cooling mechanism alone, evacuation is accomplished completely by using at first the refrigerator cooling mechanism and then using the liquid nitrogen cooling mechanism, for instance, in evacuation after the pump is opened to the atmosphere. |
