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AssigneeYokogawa Electric Corporation
InventorTakashi Sasaki
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The present invention relates to an algorithm used in a method and apparatus for controlling a paper machine, in order to automatically tune parameters used to calculate the initial value of web moisture percentage at a dryer part inlet after grade change and parameters used to calculate the dry-bulb temperature of air within a hood. In the method and apparatus, a regression line correlating the ratio of a difference in bone dry basis weight before and after grade change with a difference between the predicted value and steady-state value of steam pressure is determined from a plurality of point-of-grade-change data items, and a first parameter is calculated from the slope of this regression line. With the method and apparatus of the present invention, it is possible to automatically determine the value of the first parameter using earlier point-of-grade-change data, which used to be determined empirically. It is also possible to obtain parameter values in which the intrinsic properties of the paper machine in question are factored, by determining a regression line and calculating the values of parameters best suited to earlier data.
A method of predictive dryer control in a paper machine wherein the initial value of web moisture percentage (MP) at a dryer part inlet after grade change is determined from the sum of a value obtained by multiplying the ratio of a difference in bone dry basis weight before and after grade change by a first parameter and a value obtained by multiplying the ratio of a difference in machine speed before and after grade change by a second parameter, wherein a regression line correlating said ratio of a difference in bone dry basis weight before and after grade change with a difference between the predicted value and steady-state value of steam pressure is determined from a plurality of earlier point-of-grade-change data items and said first parameter is calculated from the slope of said regression line.
A method of predictive dryer control in a paper machine wherein the initial value of web moisture percentage (MP) at a dryer part inlet after grade change is determined from the sum of a value obtained by multiplying the ratio of a difference in bone dry basis weight before and after grade change by a first parameter and a value obtained by multiplying the ratio of a difference in machine speed before and after grade change by a second parameter, wherein a regression line correlating said ratio of a difference in bone dry basis weight before and after grade change with a difference between the predicted value and steady-state value of steam pressure is determined from a plurality of earlier point-of-grade-change data items and said second parameter is calculated from the slope of said regression line.
A method of predictive dryer control in a paper machine wherein the dry-bulb temperature of air within a hood after grade change is determined from a value obtained by multiplying an increment in steam temperature within a drum by a third parameter, wherein a regression line correlating the ratio of a difference in production volume before and after grade change with a difference between the predicted value and steady-state value of steam pressure is determined from a plurality of earlier point-of-grade-change data items and said third parameter is calculated from the slope of said regression line.
A method of predictive dryer control in a paper machine wherein the initial value of web moisture percentage (MP) after grade change is determined from the sum of a value obtained by multiplying the ratio of a difference in bone dry basis weight before and after grade change by a first parameter and a value obtained by multiplying the ratio of a difference in machine speed before and after grade change by a second parameter, and the dry-bulb temperature of air within a hood is determined from a value obtained by multiplying an increment in steam temperature within a drum by a third parameter, wherein a regression line correlating said ratio of a difference in bone dry basis weight before and after grade change with a difference between the predicted value and steady-state value of steam pressure is determined from a plurality of earlier point-of-grade-change data items, said first parameter is calculated from the slope of said regression line, a regression line correlating the ratio of a difference in production volume before and after grade change with a difference between the predicted value and steady-state value of steam pressure is determined from a plurality of earlier point-of-grade-change data items, said third parameter is calculated from the slope of said regression line, and said third parameter is corrected by means of a difference between the current value of said first parameter and the previous value of said first parameter.
An apparatus for predictive dryer control in a paper machine, comprising:
An apparatus for predictive dryer control in a paper machine, comprising:
An apparatus for predictive dryer control in a paper machine, comprising:
Dependencies are inferred from the claim text.