| 摘要 |
PURPOSE:To decrease the amt. of the gas to be conveyed over the entire part and to economize on energy by increasing the amt. of the gaseous atmosphere in a furnace during the operation for opening or shutting the door of the furnace and maintaining the gaseous atmosphere in the furnace at the prescribed amt. when the furnace is not in operation. CONSTITUTION:A solenoid valve 12 is normally held closed and a carrier gas is passed in a recarburization furnace 1 at Nm<3>/hr flow rate (A) in the heating furnace. The valve 12 is opened and the carrier gas is supplied at Nm<3>/hr flow rate (B) to the furnace 1 when a limit switch 20 operates upon opening of the furnace door 3. The flow rate of the gas in the furnace 1 is then (A+B)Nm<3>/hr. A differential pressure before and behind a limiting orifice 17 increases and a differential switch 19 is closed when the amt. of the conveying gas increases. The signal to increase the carrier gas is then emitted and the door 3 is opened to admit the carrier gas into a vestibule chamber 2. A timer starts operating and the flow rate of the carrier gas decreases when the closing of the door 3 ends. The safety against explosion during the opening or closing operation of the door is assured by the above-mentioned method. |
