Measurement system for improved paper roll runnability

Abstract

A system for measuring both caliper and tension of a web such as paper wound into a roll. The system may include a standard caliper sensor whose air supply is selectively modified to allow for both the measurement of caliper and tension of the web. In another embodiment two similar or identical measurement devices are installed in tandem where one device measures tension without pinching the sheet and the other device measures caliper. The sensor may include two sheet guides for providing support for tension measurement or one or both sheet guides can be eliminated by support from machinery rolls.

1 . A method for measuring in a direction across a moving web both tension and caliper of said moving web comprising: 
 using a single sensor to measure tension and caliper of said moving web at a location on said moving web;    providing support for said moving web before and after said location on said moving web where said single sensor measures tension and caliper of said moving web; and    controlling said single sensor to alternate between two operating modes where in one of said two operating modes said single sensor measures caliper of said moving web and in another of said two operating modes said single sensor measures tension of said moving web.    
     
     
         2 . The method of  claim 1  further comprising causing said single sensor to move transversely across said moving web.  
     
     
         3 . The method of  claim 1  wherein said single sensor is controlled upon demand or at predetermined intervals to alternate between said two operating modes.  
     
     
         4 . The method of  claim 1  further comprising controlling air pressure to said single sensor to thereby cause said single sensor to alternate between said two operating modes.  
     
     
         5 . The method of  claim 1  wherein said single sensor has first and second sensing planes on opposite sides of said moving web and said controlling said sensor to alternate between said two operating modes comprises extending in one of said two operating modes both said first and said second sensing planes to measure caliper of said moving web and extending in the other of said operating modes only said first sensing plane to measure tension of said moving web.  
     
     
         6 . The method of  claim 4  wherein said single sensor has first and second sensing planes on opposite sides of said moving web and said controlling of air pressure to said single sensor further comprises controlling said air pressure in one of said two operating modes to extend both said first and said second sensing planes to measure caliper of said moving web and controlling air pressure to only said first sensing plane to measure tension of said moving web.  
     
     
         7 . The method of  claim 5  wherein said moving web has a predetermined thickness and said sensor is controlled in said other operating mode to extend only said first sensing plane to lightly touch said moving web to thereby deflect said moving web by an amount that is larger than said predetermined web thickness.  
     
     
         8 . The method of  claim 4  further wherein said air pressure to said single sensor is adjustably controlled.  
     
     
         9 . A single sensor for measuring in a direction across a moving web both tension and caliper of said moving web at a location on said moving web comprising: 
 means for operating said single sensor to alternate between said caliper measurement and said tension measurement.    
     
     
         10 . The single sensor of  claim 9  further comprising a guide for supporting said moving web either before, after or both before and after said location.  
     
     
         11 . The single sensor of  claim 10  wherein said guide for supporting said moving web is selected from rollers, sliding contact bars or non contacting air bearings.  
     
     
         12 . The single sensor of  claim 9  further comprising: 
 means for measuring caliper of said web at said location on said moving web; and    means for operating said caliper measuring means to upon demand or at selectable intervals alternate between said caliper measurement and said tension measurement.    
     
     
         13 . The single sensor of  claim 12  wherein said means for measuring caliper of said web at said location on said moving web comprises first and second sensing planes located on opposite sides of said moving web, said single sensor measuring caliper of said moving web when said first and said second sensing planes are both activated and said means for operating said caliper measuring means to upon demand or at selectable intervals alternate between said caliper measurement and said tension measurement deactivates at said selectable alternate intervals a selected one of said first and said second sensing planes.  
     
     
         14 . The single sensor of  claim 9  wherein said means for operating said single sensor to alternate between said caliper measurement and said tension measurement operates said sensor upon demand or at selectable intervals.  
     
     
         15 . The single sensor of  claim 9  wherein said means for operating said sensor to alternate between said caliper measurement and said tension measurement comprises means for providing controllable air pressure to said single sensor to thereby cause said single sensor to alternate between said caliper measurement and said tension measurement.  
     
     
         16 . The single sensor of  claim 15  further comprising first and second sensing planes on opposite sides of said moving web and said means for controlling of air pressure to said single sensor further comprises means for controlling said air pressure in said caliper measurement to extend both said first and said second sensing planes and controlling said air pressure in said tension measurement to only extend said first sensing plane.  
     
     
         17 . The single sensor of  claim 13  wherein said moving web has a predetermined thickness and said sensor is controlled in said tension measurement to extend only said first sensing plane to lightly touch said moving web to thereby deflect said moving web by an amount that is larger than said predetermined web thickness.  
     
     
         18 . The single sensor of  claim 15  wherein said means for providing controllable air pressure is adjustably controlled.  
     
     
         19 . A method for measuring in a direction across a moving web both tension and caliper of said moving web comprising: 
 using two sensors in tandem to measure at a location on said moving web tension of said moving web by one of said two sensors and caliper of said moving web by another of said two sensors.    
     
     
         20 . The method of  claim 19  further comprising supporting said moving web before and after said tension measurement by at least one guide associated with said one of said two sensors.  
     
     
         21 . A system for measuring at a location on a moving web both caliper and tension of said moving web comprising: 
 a sensor for measuring caliper of said moving web in tandem with a sensor for measuring tension of said moving web;    at least one guide associated with said sensor for measuring tension of said moving web to support said moving web during said tension measurement.    
     
     
         22 . The system of  claim 21  further comprising a first guide associated with said sensor for measuring tension of said moving web before said tension measurement and a second guide associated with said sensor for measuring tension of said moving web just after said tension measurement.  
     
     
         23 . A quality control system for a web making machine comprising: 
 a scanning frame having an opening through which a moving web passes;    a sensor mounted in said scanning frame for measuring at locations across said moving web both tension and caliper of said moving web, said scanning frame operable to cause said sensor to move back and forth across said moving web; and    means for operating said sensor to alternate between said caliper measurement and said tension measurement.    
     
     
         24 . A web making machine comprising: 
 a system for controlling quality of said web comprising:    a scanning frame having an opening through which a moving web passes;    a sensor mounted in said scanning frame for measuring at locations across said moving web both tension and caliper of said moving web, said scanning frame operable to cause said sensor to move back and forth across said moving web; and    means for operating said sensor to alternate between said caliper measurement and said tension measurement.