| 摘要 |
PROBLEM TO BE SOLVED: To reliably prevent temperature in a vacuum tank body 1 from being disturbed by improving a vacuum tank of temperature adjustment type. SOLUTION: Gas in the vacuum tank body 1 is evacuated by a vacuum pump 6, whereby the inside of the vacuum tank body is kept into a negative pressure. In order to control the negative pressure precisely, the gas of which the flow rate is controlled by a flow rate controller 11 is sucked through a pressure control part 5. Because temperature of the sucked air flow is not controlled, there is concern of disturbing the temperature in the vacuum tank body 1. In this invention, the sucked gas flow through the pressure control part 5 is not made to flow into the vacuum tank body 1 and is caused to flow into the suction side of an exhaust part 4. Thereby, an effective exhaust amount of the vacuum pump 6 is compensated and reduced, therefore, an inflow gas flow (arrow (b)) is controlled by the flow rate controller 11 and, thereby, the gas pressure in the vacuum tank body 1 can be precisely reduced in a short time while keeping a constant temperature. COPYRIGHT: (C)2007,JPO&INPIT
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