Method for controlling the formation of a fiber web of a fiber or paper producing process

Abstract

A method for controlling the formation of a fiber web of a fiber or paper producing process includes a plurality of successive individual method steps in which controllable chemical and/or physical sequences or process steps are carried out in dependence on measured values. The materials required for the formation of the fiber web are treated, combined, and/or dewatered in the sequences or process steps. At least some of the measured values are detected inline and directly or indirectly used in order to control the formation. At least the manipulated variables, which influence the formation in a relevant manner, of the individual sequences or processes are formed dependent on definable secondary conditions during the entire process.

1 - 15 . (canceled) 
     
     
         16 . A method for controlling the formation of a fiber web in a production process (fiber or paper-production), the method comprising:
 performing a plurality of successive individual method steps and thereby acquiring measured values;   carrying out controllable chemical and/or physical sequences or process steps, respectively, in which materials required for generating the fiber web are treated, combined, and/or dewatered in dependence on the measured values, and thereby detecting at least some of the measured values inline and directly or indirectly using the measured values for controlling the formation; and   generating at least manipulated variables of the individual sequences or processes, respectively, which influence the formation in a relevant manner in the entire process in dependence on definable secondary conditions.   
     
     
         17 . The method according to  claim 16 , which comprises generating the manipulated variables depending on a definable costing function. 
     
     
         18 . The method according to  claim 17 , wherein the costing function evaluates a cost of expenditures arising as a result of a modification of the manipulated variables. 
     
     
         19 . The method according to  claim 17 , wherein the costing function evaluates consequential costs arising as a result of a modification of the manipulated variables. 
     
     
         20 . The method according to  claim 16 , wherein one of the secondary conditions is an equality condition. 
     
     
         21 . The method according to  claim 16 , wherein one of the secondary conditions is an inequality. 
     
     
         22 . The method according to  claim 16 , which comprises generating the secondary conditions depending on the initial materials or raw materials, respectively, and/or on the chemicals, auxiliaries, and energy supplied in the successive method steps, as well as on the materials and emissions to be disposed of. 
     
     
         23 . The method according to  claim 17 , which comprises minimizing the costs with the costing function by way of an optimizing algorithm while adhering to the secondary conditions. 
     
     
         24 . The method according to  claim 23 , wherein the optimizing algorithm, in order to adhere to the secondary formation conditions, influences the manipulated variables influencing the individual sequences or processes, respectively, in the entire process so as to minimize a value of a potential deviation of the formation from a nominal value. 
     
     
         25 . The method according to  claim 23 , which comprises assigning the optimizing algorithm a stored model which, either by way of a-priori knowledge or by way of interpretation of effects of previous re-adjustments, reproduces an influence of the manipulated variables on the formation in a qualitative manner. 
     
     
         26 . The method according to  claim 16 , which comprises implementing the individual methods substantially in a stock preparation, a headbox feed, and at a wet end of a fiber-web production machine. 
     
     
         27 . The method according to  claim 26 , which comprises using at least one of the following manipulated variables in the stock preparation for controlling the formation:
 a type of retention agent;   a dosing point of retention agent;   an amount of retention agent;   a grinding performance;   a dispersion performance;   a material composition; and   an amount of fixing agent.   
     
     
         28 . The method according to  claim 26 , which comprises using at least one of the following manipulated variables in the headbox feed for controlling the formation:
 a suspension jet geometry;   a lip opening;   an aperture position;   a lamella position;   inserts position; and   a speed differential between jet and wire.   
     
     
         29 . The method according to  claim 26 , which comprises using at least one of the following manipulated variables at the wet end for controlling the formation:
 a dewatering strip geometry;   dewatering strip pressures;   a vacuum; and   a wire tension.   
     
     
         30 . The method according to  claim 16 , wherein one of the manipulated variables is a machine speed.