Inferential mass rate control system for paper refiners

Claim 2

In combination with a refiner for processing fluid paper stock which includes a pair of relatively rotatable and axially movable refining elements, a drive motor for relatively rotating said elements and a control motor for axially shifting one of said elements with respect to the other, a control system comprising means providing a signal indicative of the rise in temperature of the stock flowing through said refiner, means providing a signal indicative of the consistency of said stock, means providing a signal representative of the ratio of said first signal with respect to said second signal to provide an output signal inferentially representative of the energy per unit mass required by said refiner for the particular temperature rise of the stock passing therethrough, means for comparing said output signal with a set point signal which is representative of the desired energy per unit mass, and means for controlling said control motor in accordance with any difference between said output signal and said set point signal.

Claim 3

The combination set forth in claim 1 in which said comparing means includes a first temperature transmitter for sensing the temperature of the stock entering the refiner, a second temperature transmitter for sensing the temperature of the stock leaving the refiner, and a comparator for comparing the signal from said first temperature transmitter with the temperature for said second transmitter to provide said signal representative of the rise in temperature of the stock passing through said refiner.

Claim 4

The combination set forth in claim 2 in which said means providing a signal representative of the consistency of said stock includes a transmitter for providing a signal in accordance with the consistency of the stock, said last-mentioned means further including means for multiplying the signal provided by said consistency transmitter by a predetermined constant to provide said signal representative of the consistency of said stock, whereby said means providing a ratio of said signals fUrnishes an output signal having the inferential relationship that is representative of the energy per unit mass consumed by the refiner as said stock passes therethrough.

Claim 5

The combination set forth in claim 1 including means for providing a measured signal indicative of a given stock property and additionally controlling said control motor in accordance with any difference between said measured stock property signal and a set point signal representative of a desired stock property.

Claim 6

The combination set forth in claim 4 in which said last-mentioned means includes a transmitter for measuring the given stock property and a comparator for comparing said measured stock property signal with a desired stock property signal to provide an error signal in accordance with any difference therebetween.

Claim 7

The combination set forth in claim 5 including a comparator for comparing said error signal with said signal representative of any difference between said output signal and said first-mentioned set point signal.

Claim 8

In combination with a refiner for processing fluid paper stock which includes a pair of relatively rotatable and axially movable refining elements, a dive motor for relatively rotating said elements and a control motor for axially shifting one of said elements with respect to the other, a control system comprising a first temperature transmitter for sensing the temperature of the stock entering said refiner to produce a first temperature signal, a second temperature transmitter for sensing the temperature of the stock leaving said refiner to produce a second temperature signal, a first comparator for comparing said first and second temperature signals to provide a first error signal representative of any difference between said first and second temperature signals, a consistency transmitter for sensing the consistency of the stock flowing through said refiner to produce a signal indicative of the consistency of said stock, means for dividing said error signal by said consistency signal to provide an output signal inferentially representative of the energy per unit mass required by said refiner, a second comparator for comparing said output signal with a desired energy per bone-dry ton signal to provide a second error signal, and means for controlling said control motor in accordance with the value of said second error signal.

Claim 9

In combination with a refiner for processing fluid paper stock which includes a pair of relatively rotatable and axially movable refining elements, a dive motor for relatively rotating said elements and a control motor for axially shifting one of said elements with respect to the other, a control system comprising a first temperature transmitter for sensing the temperature of the stock entering said refiner to produce a first temperature signal, a second temperature transmitter for sensing the temperature of the stock leaving said refiner to produce a second temperature signal, a first comparator for comparing said first and second temperature signals to provide a first error signal representative of any difference between said first and second temperature signals, a consistency transmitter for sensing the consistency of the stock flowing through said refiner to produce a signal indicative of the consistency of said stock, means for dividing said error signal by said consistency signal to provide an output signal inferentially representative of the energy per unit mass required by said refiner, a second comparator for comparing said output signal with a desired energy per bone-dry ton signal to provide a second error signal, and means for controlling said control motor in accordance with the value of said second error signal.

Claim 10

The combination set forth in claim 7 including a transmitter for providing a measured signal indicative of a given stock property of the stock flowing through said refiner, a comparator for comparing said measured stock property signal with a set point signal representative of a desired stock property to provide a third error signal representative of any difference therebetween and an additional comparator for comparing said second and their error signals to provide an additional error signal, said additional error signal controlling said control motor.