Thickness Measurement Gap Compensation via Reference Sensor
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Solution Overview
Problem
Existing thickness measurement devices for wide, strip-shaped materials like coils and paper webs face challenges in maintaining measurement accuracy due to mechanical instability and thermal changes, which are exacerbated by vibrations and temperature fluctuations, leading to inaccuracies in micrometer-range measurements.
Innovation Solution
A compensation sensor is coupled with path measuring sensors to continuously or intermittently measure the distance from a reference ruler, allowing for compensation of changes in the measuring gap, thereby maintaining measurement accuracy without the need for high-stability materials or complex mechanical structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional materials and simple mechanical structures are used for the measuring mechanism, then cost and simplicity are improved, but measurement precision deteriorates due to thermal expansion and vibrations
Solution Approach 1:
The patent replaces the mechanical approach of maintaining a stable measuring gap through rigid, temperature-stable materials with an optical/electronic system. Displacement sensors (optical, capacitive, or inductive) measure the actual positions of the measurement beams relative to the material surfaces, and the control unit calculates thickness based on these electronic signals rather than relying on mechanical stability. This substitution allows conventional materials to be used while maintaining micrometer-range measurement accuracy.
2Measurement precision
If temperature-stable materials like Invar are used to maintain measurement gap stability, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent eliminates the need for temperature-stable materials like Invar by replacing the mechanical stability requirement with an electronic measurement system. The displacement sensors continuously monitor the positions of the measurement beams, and the control unit compensates for any mechanical drift through calculation, allowing the use of conventional, simpler materials without sacrificing measurement precision.
Solution Approach 2:
The measuring mechanism performs self-compensation for thermal expansion and mechanical drift. The displacement sensors continuously monitor the actual positions of the measurement beams, and the control unit automatically adjusts the thickness calculation based on these measurements, eliminating the need for external compensation mechanisms or special materials.
3Measurement precision
If the distance between measurement beams is kept constant through rigid mechanical structures, then measurement precision is improved, but adaptability to vibrations and thermal changes worsens
Solution Approach 1:
The measuring mechanism continuously self-adjusts to environmental changes. The displacement sensors monitor the actual positions of the measurement beams in real-time, and the control unit automatically compensates for vibrations and thermal expansion by calculating thickness based on the current beam positions rather than assuming a fixed measuring gap. This makes the system adaptable to varying environmental conditions while maintaining precision.
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 ensures a robust, industrially suitable measuring mechanism with high accuracy for measuring web and piece goods, using conventional materials and reducing the impact of vibrations and thermal changes, while being cost-effective and simple to integrate.
Implementation Method 1
Optical sensors (triangulation, confocal measurement technology)
Implementation Method 2
Optical sensors (triangulation, confocal measurement technology)
Implementation Method 3
eddy current sensors
Implementation Method 4
capacitive sensors
Implementation Method 5
ultrasonic sensors
Implementation Method 6
radiometric sensors (beta emitters)
Implementation Method 7
length expansion as a result of temperature changes
Implementation Method 8
vibrations or can be caused by length expansion as a result of temperature changes
Data Source
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AI summary
An apparatus for measuring the thickness of a measurement object, preferably a measurement object in the form of a web or piece goods, in a measuring gap, with a measuring mechanism which is fitted to a machine frame, wherein the measuring mechanism for measuring the thickness comprises one or more travel measurement sensor(s) aimed at the measurement object, is characterized in that a compensation sensor which is coupled to a travel measurement sensor measures the distance to a reference rule in order to detect and compensate for a change in the measuring gap, in that the reference rule is in the form of a side of a frame-shaped reference device integrated in the measuring mechanism, and in that the reference device is configured in such a manner that the distance between the reference rule and that side of the reference device which is opposite the reference rule is known during the thickness measurement. A corresponding method for measuring the thickness is also stated.