Patent ID: 7412350

Claim:
A method for estimating disturbances in a refiner, comprising: measuring during an actual operation of the refiner a first operating condition and a second operating condition of the refiner, said refiner having refiner plates configured to apply a rotational abrasive fibrillating force to a fibrous material passing through the refiner plates; generating a predicted first operating condition and a predicted second operating condition which is different from the predicted first operating condition; comparing during said actual operation of the refiner the measured first operating condition to the predicted first operating condition to determine an unpredicted first operating condition; comparing during said actual operation of the refiner the measured second operating condition to the predicted second operation condition to determine an unpredicted second operating condition; estimating during the actual operation of the refiner a first disturbance in the refiner based on a first weighted sum of the unpredicted first and second operating conditions; and providing a control signal for the refiner based on the estimated first disturbance.