Oxide Layer Thickness Measurement Using Emissivity Sub-ranges
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for measuring the thickness of an oxide layer on steel sheets face challenges in accuracy due to the monotonic increase and subsequent decrease in emissivity, making it difficult to determine the thickness beyond a certain point, and the small change in emissivity leading to significant changes in layer thickness, especially at longer wavelengths.
Innovation Solution
The oxide layer thickness measurement device measures emitting light luminances at different wavelengths and calculates emissivity, using layer thickness conversion information to determine the thickness within specific sub-ranges where the ratio of emissivity change to thickness change falls within a preset extent, allowing for accurate measurement across a wider range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the emissivity-thickness relation is used for calculation, then the thickness can be determined within a limited range, but the measurement fails when emissivity reaches peak and cannot measure beyond
Solution Approach 1:
The measurement range is divided into multiple sub-ranges, with each sub-range having its own conversion information stored in the storage unit. The control unit selects the appropriate sub-range based on the measured emissivity value, enabling continuous measurement across the entire range by segmenting the problematic monotonic relation into manageable sections where each section has a unique thickness-emissivity correspondence.
2Adaptability or versatility
If the ratio of emissivity change to thickness change is small, then the measurement can cover wider range, but the thickness significantly changes with slight emissivity difference reducing accuracy
Solution Approach 1:
The system dynamically adjusts the measurement approach by selecting different conversion information based on the measured emissivity value. When the emissivity-thickness relation has a small slope (low sensitivity), the system switches to using conversion information from a different sub-range where the slope is more favorable, thereby maintaining measurement accuracy across varying conditions.
3Measurement precision
If multiple wavelengths are used for measurement, then the measurement accuracy and range improve, but the device complexity and cost increase
Solution Approach 1:
The system pre-calculates and stores conversion information for multiple wavelengths in the storage unit before actual measurement. During measurement, the control unit selects the appropriate pre-prepared conversion information based on the measured wavelength and emissivity, avoiding the need for complex real-time multi-wavelength analysis hardware while still benefiting from multi-wavelength measurement capabilities.
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 more accurate measurement of oxide layer thickness across a broader range by dividing the measurement range into sub-ranges with specific wavelength settings, improving resolution and measurement accuracy while reducing costs by using emitting light thermometers instead of spectro-luminometers.
Implementation Method 1
calculating, based on the emitting light luminances and the temperature, an emissivity of the surface of the steel sheet
Implementation Method 2
a temperature measurement part for measuring a temperature of the surface of the steel sheet
Data Source
AI summary
An oxide layer thickness measurement device according to the present invention stores, for each of layer thickness measurement sub-ranges constituting a layer thickness measurement range, layer thickness conversion information representing a correlation between a layer thickness and an emissivity where a ratio of a change in the emissivity to a change in the layer thickness in the layer thickness measurement sub-range falls within a set extent. Emitting light luminances of a surface of a steel sheet are measured at respective measurement wavelengths different from each other, and a temperature of the surface of the steel sheet is measured to thereby calculate the emissivity at each of the measurement wavelengths. Calculated in connection with the emissivity calculated at each of the measurement wavelength are the layer thickness corresponding to the emissivity at the measurement wavelength, and a ratio at the layer thickness by using the layer thickness conversion information corresponding to the measurement wavelength. The calculated thickness is extracted as a candidate value for an actual layer thickness when the calculated ratio is within the preset extent assigned for the layer thickness conversion information.