| 摘要 |
PROBLEM TO BE SOLVED: To provide an evacuation device capable of avoiding sudden decompression in a vacuum chamber using a constitution simpler than a conventional one when evacuating the chamber. SOLUTION: The evacuation chamber 1 has a main pipe 4 connected thereto via a first opening/closing valve 5 and a vacuum pump 3 is connected to the tip of the main pipe 4. A second opening/closing valve 6 is inserted in the middle of the main pipe 4, and a bypass pipe 7 is connected in parallel to the second opening/closing valve 6. When the inside of the vacuum chamber 1 starts to be evacuated, at first, it is evacuated with the second opening/closing valve 6 closed via the bypass pipe 7 at a low speed. After the inside of the vacuum chamber 1 reaches a preset degree of vacuum, the second opening/closing valve 6 is opened and the inside of the vacuum chamber 1 is continuously evacuated via the main pipe 4 and the bypass pipe 7. This constitution can prevent the sudden decompression in the vacuum chamber 1 to prevent flying-up of particles and dew condensation in the chamber. COPYRIGHT: (C)2003,JPO
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