Fluorescent Tracer Method for Papermaking Surface Additive Control
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Solution Overview
Problem
Current methods for measuring surface additives in papermaking processes are inaccurate and unreliable, often leading to overapplication of starch, with manual techniques and previous metering methods failing to control variations effectively.
Innovation Solution
A method involving the addition of inert fluorescent tracers with surface additives, allowing for fluorescence measurement using a reflectance-based fluorometer to correlate additive concentration with coating thickness, enabling precise control of additive application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual techniques and mass balance calculations are used to measure surface additives, then the measurement process is simple to implement, but the measurement precision and reliability are poor leading to overapplication of starch
Solution Approach 1:
The patent introduces fluorescent tracers as intermediary substances that are mixed with surface additives in a known ratio. These tracers serve as measurable proxies that allow indirect but accurate measurement of surface additive concentration through fluorescence intensity, resolving the contradiction between measurement accuracy and system simplicity.
Solution Approach 2:
The patent replaces manual measurement techniques and mass balance calculations with an optical detection system based on fluorescence measurement. This substitution provides automated, objective, and precise measurement of surface additives, eliminating the inaccuracies of manual methods while maintaining operational simplicity through non-contact optical detection.
2Loss of substance
If metering size press applications with blade application technique are used, then starch application can be reduced by 50-70%, but the reliability is poor due to unpredicted and uncontrolled variations of starch pickup
Solution Approach 1:
The patent implements a closed-loop feedback system where fluorescence measurements are continuously taken from the paper web, and the results are used to automatically adjust the dosage of surface additives and fluorescent tracers. This real-time feedback eliminates the uncontrolled variations in starch pickup while enabling precise control at reduced application levels.
Solution Approach 2:
The patent replaces mechanical blade application techniques with a system that uses fluorescent tracers and optical detection to control starch application. This substitution provides precise measurement and control of starch pickup, eliminating the unpredicted variations inherent in mechanical blade application while maintaining reduced starch usage.
3Reliability
If puddle style size presses are used to ensure enough starch is added, then the reliability of starch application is improved, but the loss of substance increases due to overapplication
Solution Approach 1:
The patent uses real-time fluorescence measurement feedback to precisely control the dosage of surface additives, replacing the overapplication approach of puddle style size presses. This feedback control ensures consistent and reliable starch application at optimal levels, eliminating excess starch waste while maintaining application reliability.
Solution Approach 2:
The patent changes the measurement parameter from indirect mass balance calculations to direct fluorescence intensity measurement. This parameter change enables precise quantification of surface additive concentration, allowing reliable application control at optimized dosage levels and eliminating the need for overapplication that characterizes puddle style size presses.
4Measurement precision
If fluorescent tracers are added in known proportion with surface additives, then the measurement precision of surface additives is improved, but the device complexity increases due to the need for fluorometer and correlation systems
Solution Approach 1:
The patent makes the fluorescent tracer system universal by using tracers that can be detected by standard fluorometers already present in many papermaking facilities for other purposes. The system correlates fluorescence intensity with surface additive concentration through a universal relationship, allowing the same measurement infrastructure to serve multiple functions and reducing overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for accurate and timely measurement of surface additives, enabling the reduction of starch application to low levels while predicting and controlling out-of-specification rates, improving process efficiency and reducing waste.
Implementation Method 1
adding a known amount of a composition containing one or more surface additives to a papermaking process either alone or in known proportion with a known amount of one or more inert fluorescent tracers
Implementation Method 2
measuring the fluorescence of the surface additives and/or one or more inert fluorescent tracers
Data Source
AI summary
A method of monitoring and optionally controlling the addition of one or more surface additives to a papermaking process via fluorometric means is disclosed.