| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum system, in which a desired exhaust speed can be acquired without employing pumps allowing a high exhaust speed, the inside diameter of piping can be reduced, and the consumption power of calefaction means for piping heating is curbed. SOLUTION: The vacuum system comprises a vacuum container 10, 11, and 12 each having a gas inlet and outlet, a first vacuum pump 1, 2, and 3 for keeping inside of the above vacuum containers decompressed, and a second vacuum pump 4, 5, and 6 connected to the above first vacuum pumps; wherein, in the section between the vacuum containers and the first vacuum pumps, a gas flow in the piping A2 is a molecular flow or a median flow between the molecular flow and a viscous flow, and in the section between the first vacuum pump 1, 2, and 3 and the second vacuum pump 4, 5, and 6, the gas flow in the piping A1 is the viscous flow.
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