| 摘要 |
PROBLEM TO BE SOLVED: To provide a degassing device for a holding furnace for low-pressure casting which does not require the insertion and removal of a blowing nozzle into the holding furnace at every degassing, does not require the equipment and driving power for horizontally rotating the blowing nozzle, does not increase the formation of oxide by disturbance in a molten metal surface as the molten metal is not strongly stirred, substantially prevents the clogging of the blowing nozzle when the degassing device is not necessary and can reduce the consumption of nonoxidizing gas. SOLUTION: The degassing device DG has, a nonoxidizing gas supply piping 5 which connects the blowing nozzle 4 and nonoxidizing gas supply sources 21 and 22 and is disposed with an electromagnetic stop valve 6 and a pressure regulating valve 7 in its mid-way and a controller 9 which controls the opening and closing of this electromagnetic stop valve 6 according to a prescribed blowing mode. The pressure of the nonoxidizing gas on the secondary side of the pressure regulating valve is regulated and controlled to the pressure lower than the maximum pressurizing pressure in the holding furnace for preventing the nonoxidizing gas from the blowing nozzle 4 from being blown into the molten metal.
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