METHOD FOR REMOVING FROZEN-ON METAL FROM TUYERE FOR GAS BLOWING OF MELT Russian patent published in 2007 - IPC C21C7/72 C21C5/32 

FIELD: metallurgical processes, namely processes for controlling and monitoring parameters of blast mode at blowing melts in ladle with neutral gases.

SUBSTANCE: method comprises steps of measuring pressure value in front of tuyere, descending tuyere to lower position and continuously registering pressure value in front of tuyere for the whole blowing period. Signal characterizing pressure is smoothed and time quantized. Dynamics of changing obtained time succession is analized from time moment of descending tuyere to lower position and till starting its lifting. According to progress of process difference Δ₁ between last pressure value and previous pressure value is determined. When said difference is more than 0, increased rate of metal freezing upon walls of tuyere is detected. In addition flow rate of supplied gas is measured and such value is continuously registered for the whole blowing period. Obtained signals are smoothed, time quantized and dynamics of change of time succession of signals is analyzed from time moment of descending tuyere to lower position till starting its lifting. According to progress of process difference Δ₂ between last flow rate value and its next value is determined. When Δ₁ > 0 and Δ₂ < 0 it is necessary to sharply increase gas supply to tuyere in order to significantly change pressure of emitting stream and to create dynamic shock for "pressing out" melt frozen on nozzle of tuyere and for freeing its opening at least partially. If even one of said conditions is not realized gas is supplied to tuyere in standard mode. In such case gas supply to tuyere may be sharply increased by connecting AND-regulator with high gain to circuit of gas supply.

EFFECT: lowered degree of melt freezing on nozzle of tuyere, increased useful time period of tuyere operation, enhanced condition for agitating melt.

2 cl, 1 dwg