| 摘要 |
PROBLEM TO BE SOLVED: To provide a differential exhaust sealing device capable of being reduced in costs by suppressing the number of an exhaustion evacuating pump. SOLUTION: Suppose that the inside of a second differential pressure chamber R2 be a pressure of -Δ2 by evacuating with a second evacuating pump P2, the evacuating port of a first evacuating pump P1 reaches -Δ2 of a pressure. Therefore, the inside of the first differential pressure chamber R1 reaches a pressure of -(Δ1+Δ2) by adding the evacuating performance of the first evacuating pump P1. Notwithstanding a small number of the evacuating pump with respect to a comparative example, different pressures can be applied to the differential pressure chamber so as to able to afford a simpler and more inexpensive contruction. COPYRIGHT: (C)2006,JPO&NCIPI
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