EP0408894A2 — Method for regulation and on-line measurement of …

Claim 1

Independent Claim 249 words

Method for regulation of the transverse distribution of the fibre orientation of a web produced by means of a paper machine or equivalent, wherein the transverse profile or equivalent of the discharge opening (16) of the headbox (10) of the paper machine is regulated and wherein the transverse grammage profile of the paper web (W₀...W₁) produced by means of the paper machine is measured, and the measurement signal obtained in this way is used as a feedback signal in the control system that carries out the method, characterized in that the method comprises a combination of the following steps carried out in the sequence given: (a) with the machine configuration and parameters at each particular time present in the paper machine to be controlled, data are collected concerning the relationship between the transverse distribution of fibre orientation Θ(x) i and the transverse distribution of grammage M(x) i of the web (W₀...W₁) that is being produced by, by means of the paper machine, carrying out response runs in its various states of operation (i), (b) the relation data obtained in the stage (a) specified above are stored in the memory of the computer (52) or equivalent included in the control system of the paper machine, and (c) by making use of said relation data, by means of the control system, the distribution of fibre orientation in the web (W₀...W₁) to be produced is corrected by regulating the transverse profile of the discharge opening (16) of the headbox (10) or equivalent.

Claim 2

Dependent Claim 249 words

Method for regulation of the transverse distribution of the fibre orientation of a web produced by means of a paper machine or equivalent, wherein the transverse profile or equivalent of the discharge opening (16) of the headbox (10) of the paper machine is regulated and wherein the transverse grammage profile of the paper web (W₀...W₁) produced by means of the paper machine is measured, and the measurement signal obtained in this way is used as a feedback signal in the control system that carries out the method, characterized in that the method comprises a combination of the following steps carried out in the sequence given: (a) with the machine configuration and parameters at each particular time present in the paper machine to be controlled, data are collected concerning the relationship between the transverse distribution of fibre orientation Θ(x) i and the transverse distribution of grammage M(x) i of the web (W₀...W₁) that is being produced by, by means of the paper machine, carrying out response runs in its various states of operation (i), (b) the relation data obtained in the stage (a) specified above are stored in the memory of the computer (52) or equivalent included in the control system of the paper machine, and (c) by making use of said relation data, by means of the control system, the distribution of fibre orientation in the web (W₀...W₁) to be produced is corrected by regulating the transverse profile of the discharge opening (16) of the headbox (10) or equivalent.

Claim 3

Dependent Claim 152 words

Method as claimed in claim 1, characterized in that said response runs of the paper machine comprise the following steps carried out on the basis of a program (Fig. 2A) stored in the memory of the computer (52) included in the operator's work station (50): (a) the data related to the response run, to the paper machine, and to the web to be produced are fed into said computer, (b) the reference state of the paper machine is fed (Figs. 2B and 2C), (c) based on the steps (a) and (b) specified above, for the response run a target profile of grammage is generated (Fig. 2D), (d) a change in the target profile of grammage is carried out, and the paper machine is allowed to be stabilized in the new state, and (e) the response state of the paper machine is fed (Figs. 2E and 2F), and the response run is ended.

Claim 4

Dependent Claim 117 words

Method as claimed in claim 2, characterized in that, on the basis of the program (Fig. 2A) stored in the memory of the computer included in the control system of the paper machine, preferably a microcomputer (52), the regulation stage of the method comprises the following component steps: (a) the response files, obtained from the response runs, to be included in the regulation are chosen, (b) the fibre orientation to be regulated is fed (Fig. 2G), (c) the regulation of the fibre orientation is carried out interactively (Figs. 2H, 2I and 2J), and (d) a change in the target profile of grammage is carried out in accordance with the results received, and the regulation stage is ended.

Claim 5

Dependent Claim 131 words

Method as claimed in any of the claims 1 to 3, characterized in that (a) from the database obtained in response runs, a sufficient number of response files are picked up, and changes are calculated for grammage and fibre orientation of the paper (equation (1)), (b) the equation (2) between the change in fibre orientation and the change in grammage is solved so that the solutions of the equation make said relation come true as well as possible with a sufficiently high number of response files (equation (4)), (c) a change in the target profile of grammage is calculated (equations (5) and (6)), and (d) the fault in the fibre orientation is corrected by adjusting the target profile of grammage in accordance with the change obtained in the above step (c).

Claim 6

Dependent Claim 46 words

Method as claimed in any of the claims 1 to 4, characterized in that in the method the adjustment spindles (20₁...20 N ) of the discharge opening (16) of the headbox (10) of the paper machine are adjusted by means of the regulation system (Fig. 1).

Claim 7

Dependent Claim 103 words

Method as claimed in any of the claims 1 to 5, characterized in that by means of the unit (60) for regulation of the transverse profile of fibre orientation, which unit is controlled by the computer included in the operator's work station (50), preferably a microcomputer (52), by the intermediate of a connector unit (32), the unit (60) for regulation of the transverse grammage profile is controlled, the latter unit again, by the intermediate of the connector unit (31), controlling the actuators, such as stepping-motor/angle-gear assemblies (21,25), of the adjustment spindles (20₁...20 N ) of the discharge opening (16) of the headbox (10).

Claim 8

Dependent Claim 207 words

Method for on-line measurement of the transverse distribution of the fibre orientation in a web produced by means of a paper machine or equivalent, in which method the transverse grammage profile of the web produced by means of the paper machine is measured, characterized in that the method comprises a combination of the following steps carried out in the sequence given: (a) with the machine configuration and parameters at each particular time present in the paper machine, data are collected concerning the relationship between the transverse distribution of fibre orientation Θ(x) i and the transverse distribution of grammage M(x) i of the web (W₀...W₁) that is being produced by, by means of the paper machine, carrying out response runs in its various states of operation (i), (b) the relation data obtained in the stage (a) specified above are stored in the memory of the computer (52) or equivalent included in the control system of the paper machine, and (c) by making use of said relation data, the distribution of the fibre orientation in the web (W₀...W₁) is expressed on the basis of measurement of the transverse grammage profile of the paper web and on the basis of the distribution of fibre orientation measured in the reference state.

Claim 9

Dependent Claim 207 words

Method for on-line measurement of the transverse distribution of the fibre orientation in a web produced by means of a paper machine or equivalent, in which method the transverse grammage profile of the web produced by means of the paper machine is measured, characterized in that the method comprises a combination of the following steps carried out in the sequence given: (a) with the machine configuration and parameters at each particular time present in the paper machine, data are collected concerning the relationship between the transverse distribution of fibre orientation Θ(x) i and the transverse distribution of grammage M(x) i of the web (W₀...W₁) that is being produced by, by means of the paper machine, carrying out response runs in its various states of operation (i), (b) the relation data obtained in the stage (a) specified above are stored in the memory of the computer (52) or equivalent included in the control system of the paper machine, and (c) by making use of said relation data, the distribution of the fibre orientation in the web (W₀...W₁) is expressed on the basis of measurement of the transverse grammage profile of the paper web and on the basis of the distribution of fibre orientation measured in the reference state.

Claim 10

Dependent Claim 40 words

Method for measurement of fibre orientation as claimed in claim 7, characterized in that the measured distribution of fibre orientation, and preferably also the corresponding distribution of grammage, are shown on the display screen of the measurement-system computer or equivalent.

Claim 11

Dependent Claim 36 words

Method for measurement of fibre orientation as claimed in claim 7 or 8, characterized in that the response runs to be carried out in the method comprise the steps (a),(b),(c),(d), and (e) defined in claim 2.

Claim 12

Dependent Claim 47 words

Method for measurement of fibre orientation as claimed in any of the claims 7 to 9, characterized in that the method of measurement is included as a part in the system for on-line regulation of fibre orientation as claimed in any of the claims 1 to 6.

Method for regulation and on-line measurement of the fibre orientation in a web produced by means of a paper machine

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag