APPARATUS AND METHOD FOR MAINTAINING OUTLET OF BLAST FURNACE DURING BLOWING DOWN

PURPOSE: An apparatus and a method for maintaining the outlet channel of a dust catcher for a blast furnace gas during blowing down are provided to prevent an outlet from being closed so that the outlet channel is not clogged by automatically decomposing and discharging dust precipitated into the dust catcher. CONSTITUTION: The method for maintaining an outlet of a blast furnace during blowing down comprises a first step (S61) of completing dust discharging when a temperature of the dust catcher becomes a set temperature or more by reducing blowing of air and starting discharging dust of a dust catcher; a second step (S62) of supplying diluting water into an upper short pipe in a high pressure by opening a diluting water automatic valve after supplying nitrogen into a lower short pipe of the outlet by opening a nitrogen automatic valve, and closing the diluting water automatic valve when a flow rate detected at a flow rate detector becomes a set flow rate; a third step (S63) of supplying diluting steam into the diluting water by opening the seam automatic valve when wet dust is settled; a fourth step (S64) of closing the steam automatic valve and nitrogen automatic valve when an air volume reaches a set air volume by starting reblowing; and a fifth step (S65) of discharging the diluting water by opening a sealing valve, a dust valve and a flow rate control valve after starting a pug mill.