Virtual Sensor for Predicting Paper Strength, 2000 Process Control, Electrical & Info. Conference Proceedings

Willard M. Reed, Jr., John B. Rudd--The delay in receiving strength properties information in a timely manner, is probably the most significant challenge facing today’s machine operator. In most cases, these variables are not measured directly and the operator is dependent on a laboratory test. The test sample is taken, at best, at the end a reel turn-up and the lab result is returned as much as thirty minutes to one hour later. If the test result comes back and is bad, does the operator take immediate action? He probably doesn’t. He usually waits until the next test to determine if a bad test result has occurred. In the mean time, a significant amount of production is either sold at a greatly reduced rate, or if the situation is bad enough, the reel is cut down and repulped.

This paper discusses a software methodology that creates a virtual sensor for paper strength properties that operates in real time. The operator knows how the property is changing and can take corrective action immediately. The result is tighter control of the process, less off-spec production and, in some cases, an increase in production.