PURPOSE: To uniformly heat powder and to reduce unevenness in the quality of fired products by drying the powder in a very short time of ≤10sec and carrying out this drying and firing in the same device and to prevent the contamination of the powder because impurities hardly enter the powder.
CONSTITUTION: A vertical heating furnace with a built-in furnace core tube made of quartz glass is kept at an internal temp. of 600-1,500°C and wet silica powder is fed from the top of the tube, allowed to fall freely and dried by heating with heat radiated and transferred from the heating furnace in such a state that powder density in the furnace is within the range of 100-0.1kg per 1m3 space volume of the furnace. A deposited layer of the dried powder is formed on the bottom of the tube and fired.
HIRACHI TSUTOMU
INABA HIDEYUKI
