Web caliper measurement and control system

Abstract

The present disclosure relates to systems and methods for making adjustments to the web converting machinery based upon the measured web caliper. Generally the web caliper is measured without contacting the web and in real time while the web is being conveyed at high rates of speed. The web caliper measuring system may be employed in the web converting system to improve web caliper control and improve winding. The web caliper measurement may be fed back to a calendering system to improve the caliper of web fed into a winding system, or the caliper may be fed forward to the web winding system to improve web tension and winding performance.

What is claimed is: 
     
         1 . A method of using a winding apparatus to wind a tissue web onto a core to form a rolled tissue product comprising the steps of:
 a. providing a first winding algorithm;   b. winding the tissue web about the core in accordance with the first winding algorithm;   c. measuring the caliper of the tissue web across at least a portion of the cross-machine direction of the web;   d. comparing the measured caliper to a target caliper value;   e. providing a second winding algorithm based upon the comparison of the measured caliper to the target caliper; and   f. adjusting at least one winding parameter in accordance with the second winding algorithm.   
     
     
         2 . The method of  claim 1  wherein the steps of winding the tissue web and measuring the caliper are performed concurrently and continuously during the formation of the rolled tissue product and wherein the caliper is measured across at least a 2.0 cm portion of the web. 
     
     
         3 . The method of  claim 1  wherein the at least one winding parameter is either the tension exerted on the web or the rotational speed of the core. 
     
     
         4 . The method of  claim 1  further comprising the step of conveying the web over the surface of a draw roll prior to winding the tissue web about a core and wherein the caliper is measured using a caliper measurement device disposed above the surface of the draw roll and the device comprises a light source and a detector and wherein the caliper is measured across at least a 2.0 cm portion of the web. 
     
     
         5 . The method of  claim 4  wherein the step of measuring the caliper further comprises transmitting measurement data from the caliper measuring device to a computing device in communication therewith and calculating the web caliper based upon triangulation. 
     
     
         6 . The method of  claim 1  further comprising the steps of providing a calender load profile and adjusting the calender load profile based upon the comparison of the measured caliper to the target caliper. 
     
     
         7 . The method of  claim 6  wherein the calender load profile adjusts the displacement of a first roll in a calender system relative to a second roll in the calender system. 
     
     
         8 . A web winding and measuring system comprising:
 a. a calender system;   b. a rotatably-mounted spool onto which a web of material is wound to form a roll;   c. a draw roll over which a web of material is conveyed prior to being wound to form a roll;   d. a light-emitting device configured to illuminate the web as it is conveyed over the draw roll, providing a line measuring at least 2.0 cm on the upper surface of the web in a cross-machine direction;   e. a light-receiving device configured to detect the line;   f. a means for generating measurement data from the detected line;   g. a computing device communicatively coupled to the light-receiving device and configured to receive the measurement data and calculate web caliper; and   h. a comparison means for comparing the calculated web caliper to a target web caliper value and determining whether the target web caliper has been achieved, upon determining that the at least one target characteristic has not been achieved, determine an adjustment to at least one parameter to achieve the target characteristic; and adjust the at least one parameter based on the determined adjustment.   
     
     
         9 . The web winding and measuring system of  claim 8 , wherein the determined adjustment comprises an adjustment to an amount of tension exerted on the web. 
     
     
         10 . The web winding and measuring system of  claim 8 , wherein the at least one target characteristic comprises a target number of sheets of the roll. 
     
     
         11 . The web winding and measuring system of  claim 8 , wherein the at least one target characteristic comprises a target diameter for the roll. 
     
     
         12 . The web winding and measuring system of  claim 8 , wherein the at least one target characteristic comprises a target ratio of a number of sheets of the roll to a diameter of the roll. 
     
     
         13 . The web winding and measuring system of  claim 8  further comprises a memory coupled to the computing device for generating a three dimensional profile of the web. 
     
     
         14 . A web winding and measuring system, comprising:
 a. a web tensioning system;   b. a rotatably-mounted spool onto which a web of material is wound to form a roll;   c. a draw roll over which a web of material is conveyed prior to being wound to form a roll;   d. a light-emitting device configured to illuminate the web as it is conveyed over the draw roll, providing a line on the upper surface of the web in a cross-machine direction;   e. a light-receiving device configured to detect the line;   f. a means for generating measurement data from the detected line;   g. a computing device communicatively coupled to the light-receiving device and configured to receive the measurement data and calculate web caliper; and   h. a comparison means for comparing the calculated web caliper to a target web caliper value and determining whether the target web caliper has been achieved, upon determining that the at least one target characteristic has not been achieved, determine an adjustment to at least one parameter to achieve the target characteristic;   and adjust the at least one parameter based on the determined adjustment.   
     
     
         15 . The web winding and measuring system of  claim 14 , wherein determining an adjustment to at least one parameter includes determining an adjustment to an amount of tension exerted on the web. 
     
     
         16 . The web winding and measuring system of  claim 14 , wherein determining at least one target characteristic includes determining a target number of sheets of the roll. 
     
     
         17 . The web winding and measuring system of  claim 14 , wherein determining at least one target characteristic includes determining a target diameter for the roll. 
     
     
         18 . The web winding and measuring system of  claim 14 , wherein determining at least one target characteristic includes determining a target ratio of a number of sheets of the roll to a diameter of the roll. 
     
     
         19 . The web winding and measuring system of  claim 14  further comprising generating, in a memory coupled to the computing device, a three dimensional profile of the web. 
     
     
         20 . The web winding and measuring system of  claim 14 , wherein the web tensioning system comprises a pair of draw rolls and a dancer roll.