US2002066545A1PendingUtilityA1

Method for monitoring quality of paper web

23
Priority: Jan 28, 1999Filed: Jul 27, 2001Published: Jun 6, 2002
Est. expiryJan 28, 2019(expired)· nominal 20-yr term from priority
Inventors:Jari-Matti Karjanmaa
G01N 33/346G01N 25/72D21G 9/0009
23
PatentIndex Score
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References
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Claims

Abstract

A paper web exiting a paper manufacturing machine is monitored on a continual basis, either substantially continuously or at periodic intervals, by imaging the web with a thermal camera operating in the infrared spectrum in order to detect defects such as wet spots, patches, or streaks in the base paper web and/or irregularities in a coating layer applied to the paper web in a downstream coating unit. Based on the detected defects, the manufacturing process and/or subsequent treatment process can be adjusted to eliminate the defects.

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
         1 . A method for monitoring and controlling quality of a paper web being manufactured in a paper machine, comprising: 
 conveying the paper web from an exit of the paper machine and subjecting the paper web to a treatment process;    imaging the paper web with a thermal camera on a continual basis in order to detect defects in the paper web; and    adjusting at least one of the manufacturing process and the treatment process for the paper web based on the detected defects.    
     
     
         2 . The method of  claim 1 , wherein the step of subjecting the paper web to a treatment process comprises coating the paper web with a coating material.  
     
     
         3 . The method of  claim 1 , wherein the step of subjecting the paper web to a treatment process comprises calendering the paper web.  
     
     
         4 . The method of  claim 2 , wherein the paper web is imaged prior to the treatment process.  
     
     
         5 . The method of  claim 2 , wherein the paper web is imaged after the treatment process.  
     
     
         6 . The method of  claim 2 , wherein the paper web is imaged both prior to and after the treatment process.  
     
     
         7 . The method of  claim 3 , wherein the paper web is imaged prior to the treatment process.  
     
     
         8 . The method of  claim 3 , wherein the paper web is imaged after the treatment process.  
     
     
         9 . The method of  claim 3 , wherein the paper web is imaged both prior to and after the treatment process.  
     
     
         10 . The method of  claim 1 , wherein the thermal camera images the paper web substantially continuously.  
     
     
         11 . The method of  claim 10 , wherein a video camera is used to image the paper web substantially continuously.  
     
     
         12 . The method of  claim 1 , wherein the thermal camera images the paper web at periodic intervals of time.  
     
     
         13 . The method of  claim 12 , wherein still images of the paper web are taken at periodic intervals.  
     
     
         14 . The method of  claim 1 , wherein images of the paper web taken by the thermal camera are used in order to detect nonuniformities in a characteristic of the paper web.  
     
     
         15 . The method of  claim 14 , wherein the images are used to detect nonuniformities in wetness of the paper web.  
     
     
         16 . The method of  claim 14 , wherein the images are taken after the paper web is coated with a coating layer, and the images are used to detect nonuniformities in the coating layer.  
     
     
         17 . The method of  claim 1 , wherein the imaging is performed within the infrared light spectrum of 3 to 12 micrometers in wavelength.  
     
     
         18 . The method of  claim 1 , wherein the imaging is performed within the infrared light spectrum of 3 to 5 micrometers in wavelength.  
     
     
         19 . The method of  claim 1 , wherein the imaging is performed within the infrared light spectrum of 8 to 12 micrometers in wavelength.  
     
     
         20 . The method of  claim 1 , wherein the web is conveyed to a coating unit in which a coating layer is applied to the paper web, and the coated paper web is then conveyed to a calendering unit in which the web is calendered, and wherein the coated paper web is imaged prior to entering the calendering unit in order to detect irregularities in the coating layer.  
     
     
         21 . The method of  claim 1 , wherein images of the paper web taken with the thermal camera are displayed on a monitor to enable continuous monitoring during manufacturing and treatment of the paper web.  
     
     
         22 . The method of  claim 1 , wherein an image of the paper web taken with the thermal camera is stored in a memory for further analysis.

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