Paper Web Moisture Measurement Using Scattering Element
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Solution Overview
Problem
Existing methods for optically measuring physical properties of a paper web are unreliable when attempting to assess multiple properties simultaneously.
Innovation Solution
A measurement apparatus that uses an optical radiation source, a scattering element, and a detector to measure the scattered radiation from a moving paper web, allowing for the determination of moisture and dry weight based on spectral information, with the scattering element causing single or multiple scattering to improve measurement accuracy and the detector rejecting non-scattered radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical measurement is used to assess multiple physical properties of paper web simultaneously, then measurement capability is improved, but measurement reliability deteriorates
Solution Approach 1:
The patent segments the measurement process by using multiple detectors positioned at different angles to measure different physical properties separately. Each detector measures specific properties (moisture, dry weight, etc.) by receiving scattered optical radiation at its specific angle, allowing reliable simultaneous measurement of multiple properties without mutual interference
Solution Approach 2:
The patent introduces angular dimension as a new measurement dimension by positioning detectors at different angles relative to the paper web surface. This angular differentiation allows simultaneous measurement of multiple physical properties by capturing scattered radiation from different directions, resolving the contradiction between measurement versatility and reliability
2Measurement precision
If scattered radiation is measured from moving paper web, then measurement accuracy is improved, but detector dynamical range requirements increase
Solution Approach 1:
The patent applies local quality by having each detector positioned at a specific angle to receive scattered radiation from a particular direction. This angular localization ensures that each detector measures a specific portion of the scattered radiation spectrum, reducing the overall dynamical range requirements while maintaining measurement accuracy for each physical property
Solution Approach 2:
The patent introduces the scattering element as an intermediary between the optical radiation source and the detectors. This scattering element diffuses the optical radiation and creates scattered radiation that carries information about paper web properties, enabling accurate measurement while reducing the dynamical range burden on detectors by measuring scattered rather than direct radiation
3Stability of the object's composition
If variations in distance and tilt are compensated, then measurement stability is improved, but system complexity increases
Solution Approach 1:
The patent implements feedback mechanisms to compensate for variations in distance and tilt between the scattering element and the paper web. By continuously monitoring and adjusting for these variations, the system maintains stable measurements without requiring overly complex mechanical positioning systems, resolving the contradiction between measurement stability and 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 enables reliable and repeated measurements of moisture and dry weight, reducing the dynamical range requirements for the detector and improving the accuracy of the measurement by compensating for variations in distance and tilt, thus providing a stable and precise assessment of the paper web's properties.
Implementation Method 1
The scattering element causes single or multiple scattering to improve measurement accuracy
Implementation Method 2
The detector receives side-scattered optical radiation from the paper web
Implementation Method 3
an optical radiation source that outputs optical radiation toward a scattering element
Data Source
AI summary
A measurement apparatus of a moving paper web, includes an optical radiation source that outputs optical radiation toward a scattering element of the measurement apparatus. The scattering element scatters the optical radiation, and a transmitting surface of the scattering element directs the optical radiation in a scattered manner toward the moving paper web. A distance between said transmitting surface of the scattering element and a surface of the paper web is known, and the transmitting surface and a detector of the apparatus are on opposite sides of the paper web. The detector receives at least a part of the optical radiation, which is side-scattered from the moving paper web. The detector determines a moisture value and a dry weight of the paper web on the basis of spectral information on the received optical radiation and the known distance.