Apparatus and method for winding a paper web and equipment therefor for controlling nip load

Abstract

A winding apparatus for winding a paper web, comprising a reel spool onto which the web is wound to form a paper roll, a support member forming a nip with the paper roll, and an actuator mounted at the support member or reel spool to control the distance therebetween. According to the invention the apparatus has a measuring and controlling equipment comprising a light-emitting member to illuminate the paper roll by light providing a line on the cylindrical surface of the paper roll, a receptive system arranged to depict the line, and a control unit connected to the receptive system and arranged to analyze the depicted line in order to calculate the distance between the paper roll and the support member and send a position-correcting signal to the actuator when the distance calculated deviates from a predetermined distance. The invention also relates to such a measuring and controlling equipment and a method for controlling the distance between the paper roll and the support member.

1 . A winding apparatus for winding a paper web, comprising: 
 a rotatably mounted reel spool onto which the paper web is wound to form a roll of paper;    a support member forming a nip with the roll of paper;    an actuator configured to control the distance between the support member and the roll of paper; and    a measuring and controlling equipment comprising:    a light-emitting member arranged to illuminate the roll of paper by light providing a line on the cylindrical surface of the roll of paper;    a receptive system arranged to depict the line; and    a control unit connected to the receptive system and arranged to analyze the depicted line in order to calculate the distance between the roll of paper and the support member and send a position-correcting signal to said actuator when the distance calculated deviates from a predetermined distance.    
   
   
       2 . An apparatus according to  claim 1  wherein the receptive system comprises a camera positioned and aligned to depict the line as a curve.  
   
   
       3 . An apparatus according to  claim 1  wherein upon said analysis of the depicted line the control unit is configured to calculate the radius and the axis position of the growing roll of paper.  
   
   
       4 . An apparatus according to  claim 3  wherein the support member is arranged at a known position in the apparatus, and the control unit is arranged to calculate the distance between the roll of paper and the support member on the basis of the calculated radius and axis position of the roll of paper and of a known position of the support member.  
   
   
       5 . An apparatus according to  claim 3  wherein the support member is a surface winding drum and the light-emitting member is arranged to illuminate the surface winding drum with light providing a second line on the cylindrical surface of the surface winding drum; 
 wherein the receptive system is positioned and aligned to depict the second line as a curve;    wherein the control unit is arranged to analyze the depicted second line in order to calculate the radius and axis position of the surface winding drum; and    wherein the control unit is arranged to calculate the distance between the growing roll of paper and the surface winding drum on the basis of the calculated radii and axis positions of the roll of paper and the surface winding drum.    
   
   
       6 . An apparatus according to  claim 3  wherein the control unit is configured to calculate the peripheral speed of the roll of paper by multiplying the radius of the growing roll of paper by the speed of rotation of the roll of paper, compare the calculated peripheral speed with a desired peripheral speed, and send a signal correcting the rotational speed to a drive unit of the reel spool when the calculated peripheral speed deviates from the desired speed.  
   
   
       7 . An apparatus according to  claim 1  wherein upon said analysis of the depicted line on the cylindrical surface of the roll of paper the control unit is arranged to digitalize the depicted line, identify a plurality of points on the line, calculate the equation of the line on the basis of the relative positions of the points, and calculate the radius and axis position of the roll of paper on the basis of the equation of the line.  
   
   
       8 . An apparatus according to  claim 1  wherein the light-emitting member is aligned to emit light in one plane.  
   
   
       9 - 14 . (canceled)  
   
   
       15 . A method for winding a paper web, comprising: 
 rotatably mounting a reel spool onto which the paper web is to be wound to form a roll of paper;    mounting a support member forming a nip with the roll of paper;    mounting an actuator configured to control the distance between the support member and the roll of paper;    illuminating the roll of paper by light from a light-emitting member and thereby providing a line on its cylindrical surface;    depicting the line by a receptive system;    analyzing the line by a control unit connected to the receptive system;    calculating by the control unit a distance between the roll of paper and the support member; and    sending a position-correcting signal to said actuator when the calculated distance deviates from a predetermined distance.    
   
   
       16 . (canceled)  
   
   
       17 . A method according to  claim 15 , further comprising calculating the radius and the axis position of the roll of paper upon said analysis by the control unit.  
   
   
       18 . A method according to  claim 17  wherein said first calculating step comprises defining the distance between the roll of paper and the support member according to the calculated position of the roll of paper and a known position of the support member.  
   
   
       19 . A method according to  claim 17  wherein the support member is a surface winding drum and further comprising: 
 illuminating the support member in the form of a surface winding drum to provide a second line on its cylindrical surface by light from the light-emitting member;    depicting the second line as a curve;    analyzing the second line by the control unit;    calculating the radius and axis position of the surface winding drum; and    defining the distance between the roll of paper and the surface winding drum on the basis of the calculated radii and axis positions of the roll of paper and the surface winding drum.    
   
   
       20 . A method according to  claim 17 , further comprising: 
 calculating a peripheral speed of the roll of paper by multiplying the calculated radius of the roll of paper by the speed of rotation of the roll of paper;    comparing the calculated peripheral speed of the roll of paper with a desired peripheral speed; and    sending a signal correcting the rotational speed to the drive unit of the reel spool when the calculated peripheral speed deviates from the desired peripheral speed.    
   
   
       21 . A method according to  claim 15  wherein said analyzing step comprises: 
 digitizing the depicted line;    identifying a plurality of points on the line;    calculating the equation of the line on the basis of the relative positions of the points; and    calculating the radius of curvature and the center of curvature of the roll of paper on the basis of the equation of the line.    
   
   
       22 - 35 . (canceled)  
   
   
       36 . A winding apparatus for a paper web, the apparatus comprising: 
 a rotatable reel spool configured to receive the web thereon to form a paper roll;    a support member adjacent to the growing paper roll, the support member and the growing paper roll defining a nip therebetween;    an actuator configured to control a nip load between the growing paper roll and the support member;    a light emitting member arranged apart from the support member and configured to emit a light pattern onto a portion of the growing paper roll;    a light detection device configured to receive a reflection of the light pattern from the growing paper roll; and    a control unit in communication with the light detection device and configured to determine a value representative of the nip load between the growing paper roll and the support member based on the reflection of the light pattern from the growing paper roll,    wherein the control unit is configured to communicate with the actuator to provide a desired nip load between the growing paper roll and the support member by moving the actuator.    
   
   
       37 . An apparatus according to  claim 36  wherein the control unit is configured to calculate a radius of the growing paper roll and a position of a rotational axis of the growing paper roll based on the reflection of the light pattern received from the growing paper roll.  
   
   
       38 . An apparatus according to  claim 36  wherein the value representative of the nip load, between the growing paper roll and the support member is an indentation of the support member into the growing paper roll.  
   
   
       39 . An apparatus according to  claim 36  wherein the support member is positioned at a predetermined position in the apparatus and the control unit is configured to determine the value representative of the nip load according to a calculated radius and axial position of the growing paper roll relative to the predetermined position of the support member based on the reflection of the light pattern received from the growing paper roll.  
   
   
       40 . An apparatus according to  claim 36  wherein the support member is a winding drum, the light emitting member is configured to emit a second light pattern on a surface of the winding drum, the light detection device is configured to receive a reflection of the second light pattern from the winding drum, and the control unit is configured to determine the value representative of the nip load according to a calculated radius and axial position of the growing paper roll based on the reflection of the light pattern received from the growing paper roll relative to a calculated radius and axial position of the winding drum.  
   
   
       41 . An apparatus according to  claim 36  wherein the control unit is configured to calculate a peripheral speed of the growing paper roll according to a calculated radius of the growing paper roll based on the reflection of the light pattern received from the growing paper roll and a rotational speed of the growing paper roll, compare the peripheral speed to a desired peripheral speed, and control the peripheral speed of the growing paper roll according to a deviation of the peripheral speed from the desired peripheral speed.  
   
   
       42 . An apparatus according to  claim 36  wherein the control unit is configured to identify a plurality of points in said light pattern and determine a radius and center of curvature of the growing paper roll according to the plurality of points.  
   
   
       43 . An apparatus according to  claim 36  wherein the light emitting member is configured to emit light substantially in one illumination plane.  
   
   
       44 - 47 . (canceled)  
   
   
       48 . An apparatus according to  claim 36  wherein the light emitting member and the light detection device are positioned inside a width of the paper web.  
   
   
       49 . An apparatus according to  claim 36  wherein the light emitting member and the light detection device are positioned outside a width of the paper web.  
   
   
       50 - 51 . (canceled)  
   
   
       52 . A method of controlling a nip load between a growing roll of paper and a support member, the method comprising: 
 rotating a reel spool to receive a web of paper thereon to form the growing paper roll, the growing paper roll defining a nip with the support member;    emitting a light pattern from a position apart from the support member onto a surface of the growing paper roll;    receiving a reflection of the light pattern from the growing paper roll;    determining a value representative of a nip load between the growing paper roll and the support member according to the reflection of the light pattern; and    adjusting the relative distance between the growing paper roll and the support member to control the nip load.    
   
   
       53 . A method according to  claim 52  further comprising calculating a radius of the growing paper roll and a position of an axis of the growing paper roll based on the reflection of the light pattern received from the growing paper roll.  
   
   
       54 . A method according to  claim 53  further comprising: 
 emitting a second light pattern onto the support member;    receiving a reflection of the second light pattern from the support member; and    determining a position of the support member according to the reflection of the second light pattern,    wherein the value representative of the nip load is calculated according to the position of the support member and the radius and axial position of the growing paper roll.    
   
   
       55 . A method according to  claim 52  further comprising: 
 calculating a peripheral speed of the growing paper roll according to a calculated radius of the growing paper roll based on the reflection of the light pattern received from the growing paper roll and a rotational speed of the growing paper roll;    comparing the peripheral speed to a desired peripheral speed; and    adjusting the peripheral speed of the growing paper roll according to a deviation of the peripheral speed from the desired peripheral speed.    
   
   
       56 . A method according to  claim 52  wherein said determining step comprises identifying a plurality of points in said light pattern and determining a radius and center of curvature of the growing paper roll according to the plurality of points.  
   
   
       57 - 61 . (canceled)