System and method for estimating production and feed consistency disturbances

A method for estimating disturbances in a refiner, comprising:

• generating a predicted motor load and a predicted refiner consistency, said refiner having refiner plates configured to apply a rotational abrasive fibrillating force to a fibrous material passing through the refiner plates;
• measuring during an actual operation of the refiner a first motor load and a first refiner consistency;
• determining an unpredicted second motor load based on the predicted motor load and the measured first motor load;
• determining an unpredicted second refiner consistency based on the predicted refiner consistency and the measured first refiner consistency;
• estimating during said actual operation of the refiner the disturbances based on the unpredicted second motor load and the predicted second refiner consistency;
• and
• providing control signals for the refiner based on the estimated disturbances.

A computer program product comprising a computer usable medium having computer readable program code embodied in the computer usable medium that, when executed, causes a computer to:

• retrieve during an actual operation of the refiner a first operating condition and a second operating condition of a refiner, said refiner having refiner plates configured to apply a rotational abrasive fibrillating force to a fibrous material passing through the refiner plates;
• generate a predicted first operating condition and a predicted second operating condition which is different from the predicted first operating condition;
• compare 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;
• compare during said actual operation of the refiner the measured second operating condition to the predicted second operation condition to determine an unpredicted second operating conditions;
• estimate during the actual operation of the refiner a first disturbance in the refiner based on a weighted sum of the unpredicted first and second operating conditions;
• and
• provide a control signal for the refiner based on the estimated first disturbance.

A system for estimating disturbances in a refiner, comprising:

• means for receiving during an actual operation of the refiner a first operating condition and a second operating condition of the refiner, having refiner plates configured to apply a rotational abrasive fibrillating force to a fibrous material passing through the refiner plates;
• means for generating a predicted first operating condition and a predicted second operating condition of the refiner;
• means for comparing during said actual operation of the refiner the measured first operating condition to the predicted first operating condition which is different from the first operating condition to determine an unpredicted first operating condition, and for comparing the measured second operating condition to the predicted second operating condition which was predicted from the second operating condition to determine an unpredicted second operating conditions;
• means for calculating disturbances in the refiner during said actual operation of the refiner based on,
• a comparison based on a first weighted sum of the unpredicted first and second operating conditions.

A system for controlling a refiner, comprising:

• a first control system coupled to the refiner, said refiner having refiner plates configured to apply a rotational abrasive fibrillating force to a fibrous material passing through the refiner plates, the first control system being configured to measure operating conditions of the refiner;
• and
• a processing unit coupled to the control system, the processing unit being configured to,
• receive during an actual operation of the refiner a measured first operating condition and a measured second operating condition of the refiner from the control system,
• generate a predicted first operating condition and a predicted second operating condition which is different from the predicted first operating condition,
• compare 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;
• compare 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;
• estimate during the actual operation of the refiner a first disturbance in the refiner based on a weighted sum of the unpredicted first and second operating conditions;
• and
• provide a control signal for the refiner based on the estimated first disturbance,
• wherein the control system is further configured to control the refiner based on the control signal associated with the first disturbance

A fiber processing system comprising:

• a refiner having refiner plates configured to process a fibrous material by use of a rotational abrasive fibrillating force applied to the fibrous material passing through the refiner plates;
• a plurality of measurement units coupled to the refiner to measure different operating conditions of the refiner;
• a first control system coupled to the plurality of measurement units and configured to receive during an actual operation of the refiner a plurality of measured operation conditions of the refiner from the plurality of measurement units;
• a processing unit coupled to the control system and configured to estimate a production disturbance and a feed consistency disturbance of the refiner based on the plurality of measured operation conditions and based on weighted sums of predicted and unpredicted measured operating conditions;
• and
• a second control system coupled to the processing unit and configured to generate during said actual operation of the refiner a target operating condition based on the production disturbance and the feed consistency disturbance,
• wherein the first control system is further configured to control al operation of the refiner based on the target operating condition.