Yankee dryer profiler and control

Abstract

A method for creping paper includes applying an adhesive composition to an outer surface of a creping cylinder (Yankee cylinder) to form an adhesive coating, contacting paper with the adhesive coating, removing the paper and adhesive coating from the creping cylinder, and determining a quality of the adhesive coating. Determining the quality of the adhesive coating may include measuring a degree of cross-linking of the adhesive polymer, a concentration of the adhesive polymer in the adhesive coating, a water content of the adhesive coating, an ash content of the adhesive coating, or combinations thereof. Determining the quality of the adhesive coating may also include determining a thickness of the adhesive coating by measuring light absorbed by the coating and calculating the thickness using Beer's Law. Systems and apparatuses for determining the quality of the adhesive coating and for creping paper are also disclosed.

What is claimed is: 
     
         1 . A coating inspection system for determining a quality of an adhesive coating on a creping cylinder, the coating inspection system comprising an instrument array comprising a topography instrument, at least one spectrometer, and an infrared temperature sensor, wherein the instrument array is positioned to direct the topography instrument, the at least one spectrometer, and the infrared temperature sensor at the adhesive coating on an outer surface of the creping cylinder. 
     
     
         2 . The coating inspection system of  claim 1 , further comprising an instrument housing coupled to a first instrument positioner, wherein:
 the instrument array is disposed within the instrument housing; and   the first instrument positioner is operable to translate the instrument housing laterally back and forth along a width of the creping cylinder.   
     
     
         3 . The coating inspection system of  claim 2 , wherein the instrument housing comprises a window disposed between the instrument array and the adhesive coating, wherein the instrument array is position to direct one or more beams of light through the window to the adhesive coating on the outer surface of the creping cylinder. 
     
     
         4 . The coating inspection system of  claim 2 , further comprising a second instrument positioner operatively coupled to the topography instrument, the second instrument positioner operable to translate the topography instrument along a direction normal to the outer surface of the creping cylinder to move the topography instrument closer to or farther away from the outer surface of the creping cylinder. 
     
     
         5 . The coating inspection system of  claim 1 , wherein the topography instrument is operable to measure one or more properties of the adhesive coating on an outer surface of the creping cylinder. 
     
     
         6 . The coating inspection system of  claim 5 , wherein the topography instrument comprises:
 a light source system operable to direct a beam of light towards the adhesive coating at an angle and measure an initial intensity of the beam of light, wherein the angle is a non-zero angle of the beam of light relative to a direction normal to the outer surface of the creping cylinder;   an imaging system operable to capture an image of a cross-section of the beam after the beam is reflected from the outer surface of the creping cylinder and passed back through the adhesive coating; and   a beam intensity measuring system operable to measure a final intensity of the beam after the beam passes through the adhesive coating and is reflected from the outer surface of the creping cylinder.   
     
     
         7 . The coating inspection system of  claim 1 , wherein the at least one spectrometer comprises a first spectrometer operable to determine one or more of a concentration of an adhesive polymer in the adhesive coating, a degree of cross-linking of the adhesive polymer, the concentration of one or more other constituents of the adhesive coating, or combinations of these. 
     
     
         8 . The coating inspection system of  claim 7 , wherein:
 the first spectrometer is operable to pass light having wavelengths in a range of from 200 nm to 1000 nm through the adhesive coating and measure wavelengths and intensities of the light passed through the adhesive coating and reflected from the outer surface of the creping cylinder or fluoresced by the adhesive coating; and   the first spectrometer is operable to determine an absorbance spectrum, a fluorescence spectrum, or both of the adhesive coating from the wavelengths and intensities of the light passed through the adhesive coating or fluoresced by the adhesive coating; and   at least one of a concentration of an adhesive polymer in the adhesive coating, a degree of cross-linking of the adhesive polymer, or both is determined from the absorbance spectrum, fluorescence spectrum, or both.   
     
     
         9 . The coating inspection system of  claim 7 , further comprising a second spectrometer operable to determine a concentration of water in the adhesive coating, an ash content in the adhesive coating, or both. 
     
     
         10 . The coating inspection system of  claim 9 , wherein:
 the second spectrometer operable to pass near infrared light having wavelengths in a range of from 750 nm to 2500 nm through the adhesive coating and measure wavelengths and intensities of the near infrared light reflected from the adhesive coating and the outer surface of the creping cylinder;   the second spectrometer is operable to determine an absorbance spectrum of near infrared light for the adhesive coating from the wavelengths and intensities of the near infrared light reflected from the adhesive coating and the outer surface of the creping cylinder; and   a concentration water in the adhesive coating, an ash content in the adhesive coating, or both is determined from the absorbance spectrum of near infrared light for the adhesive coating.   
     
     
         11 . The coating inspection system of  claim 1 , wherein the infrared temperature sensor is operable to measure a temperature of the adhesive coating, a temperature of the outer surface of the creping cylinder, or both. 
     
     
         12 . A coating system for applying an adhesive coating to an outer surface of a creping cylinder, the coating system comprising:
 an adhesive system operable to prepare an adhesive composition;   an adhesive applicator positioned to apply the adhesive composition to the outer surface of the creping cylinder to form the adhesive coating; and   the coating inspection system of  claim 1 , wherein the coating inspection system is positioned downstream of the adhesive applicator relative to a direction of rotation of the creping cylinder and between the adhesive applicator and contact of a paper web with the adhesive coating.   
     
     
         13 . The coating system of  claim 12 , wherein the coating inspection system is oriented to direct the instrument array towards the adhesive coating on the outer surface of the creping cylinder. 
     
     
         14 . The coating system of  claim 12 , further comprising a control system communicatively coupled to the adhesive system, the adhesive applicator, and the coating inspection system, the control system comprising at least one processor, at least one memory module communicatively coupled to the at least one processor, and machine readable instructions stored on the at least one memory module, wherein the machine readable instructions, when executed by the at least one processor, may cause the control system to automatically:
 determine one or more than one of a thickness, a topography, or a rheology of the adhesive coating using the topography instrument, and   adjust application of the adhesive composition to the outer surface of the creping cylinder in response to the thickness, topography, or rheology of the adhesive coating.   
     
     
         15 . The coating system of  claim 12 , further comprising a repair wand positioned downstream of the coating inspection system relative to a direction of rotation of the creping cylinder. 
     
     
         16 . A method for determining a quality of an adhesive coating on an outer surface of a creping cylinder in a process for creping paper, the method comprising determining a thickness of the adhesive coating disposed on the outer surface of the creping cylinder, wherein determining the thickness of the adhesive coating comprises:
 directing a beam of light through the adhesive coating at an angle, wherein at least a portion of the beam reflects from the surface of the creping cylinder and passes back through the adhesive coating;   determining an absorbance of the beam of light by the adhesive coating from a difference between an initial intensity of the beam and a final intensity of the beam; and   calculating the thickness of the adhesive coating from the absorbance of the beam by the adhesive coating.   
     
     
         17 . The method of  claim 16 , further comprising developing a topography of the adhesive coating from a plurality of thicknesses of the adhesive coating. 
     
     
         18 . The method of  claim 17 , wherein developing the topography of the adhesive coating comprises rotating the creping cylinder and moving the beam of light back-and-forth along a width of the creping cylinder during rotation of the creping cylinder, wherein moving the beam of light along the width of the creping cylinder directs the beam of light through the adhesive coating at the angle at a plurality of points along the width of the creping cylinder. 
     
     
         19 . The method of  claim 16 , further comprising measuring at least one of a degree of cross-linking of the adhesive polymer, a concentration of the adhesive polymer in the adhesive coating, a water content of the adhesive coating, an ash and/or fiber content of the adhesive coating, or combinations thereof. 
     
     
         20 . The method of  claim 16 , wherein determining the quality of the adhesive composition comprises determining the adhesive polymer content of the adhesive coating, wherein determining the polymer content of the adhesive coating comprises:
 measuring an incoming absorbance curve of the adhesive coating using a spectrometer; and   comparing the incoming absorbance curve of the adhesive coating to a reference absorbance curve, wherein the adhesive polymer content is proportional to a magnitude of one or more absorbance peaks of the incoming absorbance curve relative to corresponding peaks of the reference absorbance curve.