THE AIR-PADDED HEADBOX AS PLANT OF THE MASS HEAD CONTROL

For papermakers the headbox is plant of exceptional importance, because it forms a thin jet of mass, which then enters the paper machine mesh on which it turns into paper. In the past, this process was almost on the brink of craft and art, but contemporary engineers have made a significant contribution to the systematization of the means and methods on which the headboxes operate or are controlled. The task is not only to make the headboxes easier to operate, but also to increase productivity and accuracy with which they can work.To control the headbox, two input control actions are required (the position of control member for air supply and the position of control member for mass feed). Unfortunately, each of the output variables (mass level, air cushion pressure and mass head) is influenced by all two input actions. For instance, if the position of air supply control members is changed, they will cause a change not only in the air pressure, but also disrupt the mass level and the mass flow in a significant range. Therefore, such an automatic control system calculation and setting can be very tedious. Thus, it is very important to have dynamic characteristics for all control variables, depending on each input action.The description of some methods that are suitable for solving this problem is the main content of this article.
Розроблено математичну модель напірного ящика із повітряною подушкою як об’єкта керування напором маси, яку пропонується використати для аналітичного конструювання мікропроцесорного регулятора напору маси.