PURPOSE: To repair the shell of a blast furnace thoroughly to withstand long- term use by lowering the level of the contents in said furnace to the level of a repairing place, charging a heat insulating sealant on the top surface thereof and renewing the damaged shell over the entire part then increasing the level of the contents and resuming ordinary operation.
CONSTITUTION: If a damage 6a such as cracking is produced in the upper part of the shell of a shaft 2, the content 9 of the blast furnace is lowered down to below the damaged place, and the blasting through tuyeres 7 is reduced as well. A heat insulating sealant, for example, ballast 12, is charged onto the top surface of the content 9 and granulated slag 13 is charged thereon. Upon complection of the charging, a gas is diffused through gas releasing pipes 15 installed in plural positions in the circumferential direction of the blast furnace in the position below the surface of the contents 11, whereby the blasting is reduced. Then, the shell having the damage 6a is replaced entirely with a new shell. When the repair is completed, the content in the blast furnace is increased and the rate of blasting through the tuyeres 7 is returned to the original rate.
YAMAMOTO YOSHITO
MOCHIZUKI AKIRA
