| 摘要 |
PROBLEM TO BE SOLVED: To control the feeding quantity of pressure control gas to maintain pressure in a hollow body at a fixed value. SOLUTION: To maintain pressure in a muffle 21 of a heat treatment apparatus 20 at a fixed value, the pressure control apparatus 10 is provided with a flow meter 2, a pressure sensor 3, a control circuit 4, a mass flow controller 6, and a pump 7. Filling gas is supplied into the muffle 21 through a feeding pipe 11 at a fixed flow rate regulated by the flow meter 2. The pump 7 exhausts the filling gas in the muffle 21 to the outside through an exhaust pipe 12. A control circuit 4 reduces or increases the feeding quantity of pressure control gas to be set in the mass flow controller 6 in accordance with whether the pressure in the muffle 21 detected by the pressure sensor 3 is higher than a regulated value or not. COPYRIGHT: (C)2007,JPO&INPIT
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