PURPOSE: To accurately inform changing timing of a bell liner by measuring dropping condition of charging material by four or more of sensors arranging from circumferential direction in a furnace top hole part toward dropping position of the charging material at the equal intervals.
CONSTITUTION: The raw material 3 staying between a bell 1 and a bell cup 2 is charged into a blast furnace from gap formed by descent of the bell 1. At the time of arranging four or more of cantilevers 12 from the circumferential direction in the furnace top hole part of the blast furnace toward the dropping position of the raw material at the equal intervals, the dropped raw material 3 collides to the cantilever 12. Vibration at this time is measured by each vibrator 13 arranged on the cantilever 12 and each time required to the raw material charging in the cantilever 12 setting position at each charging chance is detected. On the other hand, the standard time of the raw material charging is beforehand set and in case even one of every times required to the raw material charging detected by the above is shorter than the standard time of the raw material charging, it can be judged that a bell liner 4 is worn more than the standard condition in this position.
KIMURA YOSHIO
SHIMIZU SHOKEN
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