ABNORMALITY DETERMINATION METHOD AND ABNORMALITY DETERMINATION DEVICE FOR OXIMETER INSTALLED IN CONSECUTIVE TYPE HEATING FURNACE

摘要

To provide an abnormality determination method and an abnormality determination device for oximeter installed in a continuous type heating furnace in which it is possible to determine an abnormal state when a response delay time of the oximeter is long and to control without making air ratio abnormal.SOLUTION: An abnormality determination method performed by an oximeter is carried out in such a way that at a correlation coefficient calculation step S5, a correlation coefficient Rcontinuously varying from the correlation coefficient Rat a first specified time T1 to a correlation coefficient Rat a second specified time T2 is calculated, at a response delay time calculation step S6, a response delay time of an oximeter 8 ranging from a first specified time T1 in which the oxygen concentration in the exhaust gas is measured by the oximeter 8 to a time in which the correlation coefficient Rthat is continuously changed reaches to the maximum value is calculated, at the abnormality determination steps S7 to S9, when the response delay time of the oximeter 8 is longer than a predetermined threshold value, it is determined that the oximeter 8 shows an abnormal state.SELECTED DRAWING: Figure 2