PURPOSE: To improve production efficiency, cost effectiveness, safety, etc., and to improve the durability of a furnace body by specifically regulating a heating method of a firing furnace, firing time and temp. dropping conditions, etc., at the time of firing smoked roof tile.
CONSTITUTION: Many containers 14 are disposed in the furnace body 11 and roof tile bodies which are materials to be fired are placed in the respective containers 14. Firing gases are then ejected from plural pieces of burners 12 of a high-velocity type and are uniformly spread in the firing furnace 11 via passage spacings 13 to raise the temp. atmosphere of the firing furnace 11 to a firing range of 900 to 1200°C. The firing is ended in 5 to 15 hours. The roof tile bodies are then cooled by coolers mounted at the proper points in the furnace body 11 to drop the firing atmosphere in the furnace body 11 in 7 to 15 hours to a throat temp. of 300 to 450°C. The cooling is then ended. As a result, the ending of the entire operation stage within 24 hours is made possible and, therefore, there is no need for making midnight operation.
TAGUCHI YUKIJI
HOSOE KOJI
