To restrain the penetration of molten metal into a gas blowing plug at the time of shifting a ladle by arranging a circuit constituted with a gas cylinder for pressure accumulation for preventing the penetration of metal into the gas blowing nozzle at the time of shifting the ladle and three safety valves for executing the pressure accumulation into the pressure accumulation into the gas cylinder.
Gas is supplied from a gas supplying source connected with a piping connecting part 10 and the pressure is accumulated firstly into the gas cylinder 3 through the safety valve 7b. Successively, in the case the pressure in the gas cylinder 3 becomes the setting pressure of the safety valve 7a plus the back pressure of molten metal or higher, the safety valve 7a is opened and the gas blowing action is executed in the pressure accumulating condition into the gas cylinder 3. Then, after completing the gas blowing, the gas supplying source connected with the piping connecting part 10 is taken off, and at the time of stopping the gas supplying, the gas pressure- accumulated in the gas cylinder 3 is contracted into a regulating flow rate through the safety valve 7c and a switch valve 4 and supplied into the gas blowing plug 2, and the gas blowing is executed even at the time of shifting. Then, at the time of becoming the back pressure or higher, the safety valve 7c is closed.
ARAMAKI KEIZO
TOMIMATSU HIROYASU
