Apparatus and method for closed-loop control of creped tissue paper structure

Patent metadata

Field	Value
Publication number	US-9238889-B2
Application number	US-201414225703-A
Country	US
Kind code	B2
Filing date	Mar 26, 2014
Priority date	Oct 17, 2013
Publication date	Jan 19, 2016
Grant date	Jan 19, 2016

Abstract

A method includes obtaining measurements associated with one or more controlled variables related to a structure of creped tissue paper during production of the creped tissue paper. The method also includes generating at least one control signal that adjusts one or more manipulated variables associated with the production of the creped tissue paper in order to alter the structure of the creped tissue paper. The one or more controlled variables include a number of folds per unit length of the creped tissue paper, a caliper of the creped tissue paper, a macro crepe of the creped tissue paper, and/or a micro crepe of the creped tissue paper. The manipulated variable(s) could include a crepe percentage, a creping blade angle, a flow of sizing agent, and/or a cross direction (CD) profile of nozzle positions associated with a spray boom that sprays sizing agent onto a Yankee dryer.

First claim

What is claimed is:

1. A method comprising:
using at least one processing device:
obtaining measurements associated with one or more controlled variables related to a structure of creped tissue paper during production of the creped tissue paper; and
generating at least one control signal that adjusts one or more manipulated variables associated with the production of the creped tissue paper in order to alter the structure of the creped tissue paper;

wherein the one or more controlled variables include a caliper of the creped tissue paper;
wherein the caliper of the creped tissue paper is calculated using a function:
C=C 0 +C CS

where C represents the caliper of the creped tissue paper, C 0 represents a base caliper for a given grade of tissue paper, and C CS represents a crepe structure-dependent component of the caliper C; and
wherein the crepe structure-dependent component C CS of the caliper is calculated based on a dominant frequency ω of the creped tissue paper and a standard deviation σ r of an intensity of diffusely-reflected light from the creped tissue paper.

2. The method of claim 1 , wherein:
the one or more controlled variables further include a number of folds per unit length of the creped tissue paper; and
the one or more manipulated variables include at least one of: a crepe percentage, a creping blade angle, and a flow of sizing agent.

3. The method of claim 2 , wherein:
the crepe percentage is based on a rotational speed of a Yankee dryer and a rotational speed of a reel or drum that collects the creped tissue paper; and
the at least one control signal adjusts the rotational speed of the reel or drum.

4. The method of claim 1 , wherein the one or more manipulated variables include at least one of: a crepe percentage, a creping blade angle, and a flow of sizing agent.

5. The method of claim 1 , wherein:
the one or more controlled variables further include a macro crepe of the creped tissue paper; and
the one or more manipulated variables include at least one of: a crepe percentage, a creping blade angle, and a flow of sizing agent.

6. The method of claim 1 , wherein:
the one or more controlled variables further include a micro crepe of the creped tissue paper; and
the one or more manipulated variables include at least one of: a crepe percentage, a creping blade angle, and a flow of sizing agent.

7. The method of claim 1 , wherein:
the one or more manipulated variables include a cross direction (CD) profile of nozzle positions associated with a spray boom that sprays sizing agent onto a Yankee dryer; and
the one or more controlled variables include at least one of: a CD profile of the number of folds per unit length of the creped tissue paper, a CD profile of the caliper of the creped tissue paper, a CD profile of the macro crepe of the creped tissue paper, and a CD profile of the micro crepe of the creped tissue paper.

8. The method of claim 1 , wherein generating the at least one control signal comprises generating multiple control signals using multiple models, each model associating one controlled variable and one manipulated variable.

9. An apparatus comprising:
at least one processing device configured to:
obtain measurements associated with one or more controlled variables related to a structure of creped tissue paper;
determine how to adjust one or more manipulated variables associated with production of the creped tissue paper in order to alter the structure of the creped tissue paper; and
generate at least one control signal for adjusting the one or more manipulated variables;

wherein the one or more controlled variables include a caliper of the creped tissue paper;
wherein the caliper of the creped tissue paper is calculated using a function:
C=C 0 +C CS

where C represents the caliper of the creped tissue paper, C 0 represents a base caliper for a given grade of tissue paper, and C CS represents a crepe structure-dependent component of the caliper C; and
wherein the crepe structure-dependent component C CS of the caliper is calculated based on a dominant frequency ω of the creped tissue paper and a standard deviation σ r of an intensity of diffusely-reflected light from the creped tissue paper.

10. The apparatus of claim 9 , further comprising:
at least one interface configured to receive the measurements and output the at least one control signal.

11. The apparatus of claim 9 , wherein:
the one or more controlled variables further include a number of folds per unit length of the creped tissue paper; and
the one or more manipulated variables include at least one of: a crepe percentage a creping blade angle, and a flow of sizing agent.

12. The apparatus of claim 9 , wherein the one or more manipulated variables include at least one of: a crepe percentage, a creping blade angle, and a flow of sizing agent.

13. The apparatus of claim 9 , wherein:
the one or more controlled variables further include a macro crepe of the creped tissue paper; and
the one or more manipulated variables include at least one of: a crepe percentage, a creping blade angle, and a flow of sizing agent.

14. The apparatus of claim 9 , wherein:
the one or more controlled variables further include a micro crepe of the creped tissue paper; and
the one or more manipulated variables include at least one of: a crepe percentage, a creping blade angle, and a flow of sizing agent.

15. The apparatus of claim 9 , wherein:
the one or more manipulated variables include a cross direction (CD) profile of nozzle positions associated with a spray boom that sprays sizing agent onto a Yankee dryer; and
the one or more controlled variables include at least one of: a CD profile of the number of folds per unit length of the creped tissue paper, a CD profile of the caliper of the creped tissue paper, a CD profile of the macro crepe of the creped tissue paper, and a CD profile of the micro crepe of the creped tissue paper.

16. The apparatus of claim 9 , further comprising:
at least one memory configured to store multiple models, each model associating one controlled variable and one manipulated variable.

17. A non-transitory computer readable medium embodying a computer program, the computer program comprising computer readable program code for:
obtaining measurements associated with one or more controlled variables related to a structure of creped tissue paper; and
generating at least one control signal for adjusting one or more manipulated variables associated with production of the creped tissue paper in order to alter the structure of the creped tissue paper;
wherein the one or more controlled variables include a caliper of the creped tissue paper;
wherein the caliper of the creped tissue paper is calculated using a function:
C=C 0 +C CS

where C represents the caliper of the creped tissue paper, C 0 represents a base caliper for a given grade of tissue paper, and C CS represents a crepe structure-dependent component of the caliper C; and
wherein the crepe structure-dependent component C CS of the caliper is calculated based on a dominant frequency ω of the creped tissue paper and a standard deviation σ r of an intensity of diffusely-reflected light from the creped tissue paper.

18. The computer readable medium of claim 17 , wherein the computer readable program code for generating the at least one control signal comprises computer readable program code for generating multiple control signals using multiple models, each model associating

Assignees

• Honeywell Int Inc

Inventors

• Paavola Antti
• Kellomaki Markku

Classifications

• D21F11/14 Primary

  Making cellulose wadding, filter or blotting paper · CPC title

• D21G9/0045

  controlling the calendering or finishing · CPC title

• D21G9/0036

  controlling the press or drying section · CPC title

• D21F7/06 Primary

  Indicating or regulating the thickness of the layer; Signal devices · CPC title