Web Measurement Accuracy via Traversing and Array Sensor Fusion
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Solution Overview
Problem
Current methods for measuring web characteristics in paper manufacturing, such as moisture and basis weight, are either inaccurate due to calibration limitations of stationary sensor arrays or inefficient due to the need for traversing sensors to calibrate outside the web, leading to sparse and costly measurements across both machine and cross directions.
Innovation Solution
A combined measuring method using a traversing measuring unit and a stationary array measuring unit, where the traversing unit measures characteristics with one radiation type at multiple locations over time, and the array unit measures with another radiation type at different times, allowing for estimation and control of web characteristics, thereby simplifying and improving measurement accuracy and density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traversing sensor unit is used to measure web characteristics, then measurement accuracy is improved due to the ability to calibrate outside the web, but measurement density in the machine direction deteriorates because measurements are taken at extremely long intervals
Solution Approach 1:
The patent combines a traversing sensor unit and a stationary sensor array into a single measurement system. The traversing unit provides accurate calibration-based measurements, while the stationary array provides dense machine-direction coverage. By merging these two approaches, the system achieves both high measurement accuracy and dense measurement density without requiring all sensors to measure the same characteristics.
2Productivity
If a stationary sensor array is used to measure web characteristics, then measurement density in the machine direction is improved, but measurement accuracy deteriorates because sensors cannot be calibrated outside the web and are subject to dirtying
Solution Approach 1:
The stationary sensor array serves as an intermediary that provides dense measurement coverage, while the traversing sensor unit acts as a reference standard for calibration. The system uses the traversing unit's accurate measurements to periodically calibrate or validate the stationary array's measurements, allowing the array to maintain high density without sacrificing accuracy due to dirtying or lack of calibration.
3Adaptability or versatility
If all desired sensors are placed in both traversing and stationary configurations to measure all characteristics, then measurement completeness is improved, but device complexity and cost deteriorate
Solution Approach 1:
The system implements multi-functionality by having the traversing sensor unit and stationary sensor array measure different characteristics. Each sensor type is optimized for specific measurements, and the system achieves complete measurement coverage by combining these different functional capabilities rather than duplicating all sensors in both configurations.
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 enables dense and accurate web measurements without the need for both traversing and stationary sensors to measure the same characteristic, reducing costs and improving measurement speed and accuracy, allowing for real-time control of paper manufacturing processes.
Implementation Method 1
measuring, with the traversing measuring unit, at least one characteristic of the web with a first radiation type from a plurality of measuring locations during the traversing movement
Implementation Method 2
measuring, with the array measuring unit, at least one characteristic of the web with another radiation type during each traversing movement at a plurality of different moments in time by measuring the web at each moment in time at a plurality of measuring locations
Data Source
AI summary
One measuring part (106) of a traversing measuring unit (104) measures at least one characteristic of a web (14) with a first radiation type from a plurality of measuring locations (112) during a traversing movement at successive moments in time. At least two measuring parts (108) of an array measuring unit (102) measure at least one characteristic of the web (14) with another radiation type during each traversing movement at a plurality of different moments in time by directing the measurement to a plurality of measuring locations (110) in the web (14) at each moment in time. A signal processing unit (114) is arranged to estimate at least one characteristic measured by the traversing measuring unit (104) with at least one measurement of the array measuring unit (102).