US 5,825,653 AGranted

Method for overall regulation of a former of a paper machine or equivalent

AssigneeValmet Corporation

InventorsJyrki Huovila, Jari Hamalainen, Petri Nyberg, Pekka Pakarinen

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Abstract

A method for continuous overall regulation of a former of a paper or board machine or equivalent in which a physical fluid flow model of the drainage and the flow state of the pulp suspension flow is formed. The model is solved by making use of the data on the geometry of the former and initial and boundary conditions necessary for a solution to the model. The difference between the simulated state, which has been obtained as the solution of the physical flow model, and the state adopted as the target is determined as the cost function, wherein the target state is determined by means of the quality requirements of the paper and possibly by means of the costs of operation and the runnability of the paper machine. The cost function is optimized and, thus, optimal regulation values and set values are obtained for the regulation devices and/or actuators of the former in view of the given cost function. After the optimization has been carried out in the preceding stage, the former's regulation devices and/or actuators are given new optimal regulation and set values.

Claims24

Dependent claims

A method for optimizing the overall regulation of a former of a paper or board machine in which a pulp suspension flow is drained to produce paper, comprising the steps of:

(a) forming a physical fluid flow model of the drainage and flow state of the pulp suspension flow in the former;
(b) solving the flow model to obtain a simulated flow state based on data on the geometry of the former and initial and boundary conditions related to the former;
(c) obtaining a target flow state based on quality requirements of the paper;
(d) determining a difference between the simulated flow state obtained as the solution of the flow model and the target flow state, the difference constituting a cost function;
(e) optimizing the cost function and then determining optimal regulation values and set values for regulation devices and actuators which affect the drainage and flow state of the pulp suspension flow in the former in view of the cost function;
and
(f) providing the optimal regulation values and set values to the regulation devices and actuators of the former such that the regulation devices and actuators operate at the optimal regulation values and set values to thereby realize the optimization of the cost function.

4 more elements

Dependencies are inferred from the claim text.