PURPOSE: To prevent the deterioration of refractories due to thermal shocks and the variation of blast temps. by refuxing the hot air in a hot air main pipe through a hot air pipeline to pressurize a hot stove before the blasting is started.
CONSTITUTION: When a combustion stage is switched to a blasting stage in a hot air stove 11, a pressurizing valve 38 is opened immediately before the blasting is started. Consequently, a part of hot air in a hot air main pipe 36 is refluxed through a hot air pipeline 33, and sent into a regenerator (b) which is pressurized. The hot air pipeline 33 is preheated by the pressurization with hot air. Consequently, when the stage is switched to the blasting stage by opening a cold air valve 32 and a hot air valve 34, thermal shocks to refractories in the hot air pipeline 33, a decrease in the temps. of the hot air due to heat absorption by the hot air pipeline 33 and a disorder in temp. control due to the time lag in a temp. sensor can be reduced, and the operation can be carried out smoothly.
SASAKI SHIGEJI
YAMADA HARUYASU
HIRABAYASHI SHIGERU
