| 摘要 |
PURPOSE:To make easy pressure control with high accuracy with a low-pressure furnace in which the pressure during operation is held at a relatively low positive pressure by an in-furnace gas having the specific gravity different from the specific gravity of the outdoor air by controlling the in-furnace pressure by the height of a discharge port. CONSTITUTION:This furnace is constituted of a stationary column 3 communicated and fixed with a discharge column 2 of the low pressure furnace to be operated in the state of maintaining the in-furnace pressure at the slightly more positive pressure than the outdoor air to the ceiling part of a furnace body 1 and a movable column 4 which can be lifted by a lifting device 5 freely slidably mounted to the stationary column 3. A furnace pressure detecting sensor 1a detects the in-furnace pressure and outputs the same to a lifting control device 6. The sensor outputs the pressure to the lifting device 5 to increase the height of the discharge port from the discharge port 4a of the column 4 up to a furnace pressure measuring sensor 1a to a desired height if, for example, the in-furnace pressure is higher than a reference pressure.
|
