| 摘要 |
<p>A method for controlling the drying process taking place in the dryer section of a paper machine or the like. The dryer section comprises at least one drying cylinder unit (26, 28, 30, 32, 34) and at least one air impingement unit (20, 21, 22). Optimal evaporation is first compiled in a manner known as such, for example, on the basis of a recipe or by utilising a machine-direction quality model or quality profile, when the geometry of the dryer section, the process parameters required, such as machine speed, paper grade and total evaporation required are known. According to the invention, limit values are calculated for at least two controlled variables of the dryer section, such as the steam pressure p and the temperature T of blowing air, making use of drying quality models known as such, such as models representing the adhesion and brightness of paper. After this the dryer section is divided on the basis of the distribution formed by the limit values of the controlled variables into drying segments (10, 12, 14, 16), so that in two adjacent segments, the limit value of at least one controlled variable is different. The drying process is controlled by adjusting the controlled variables in each drying segment, within the limit values of the controlled variables.</p> |
