In-situ Thermometer Calibration via Solid Phase Transition
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Solution Overview
Problem
Existing methods for calibrating and validating thermometers require separate comparison measurements, which are cumbersome and prone to errors due to aging effects and sensor drift in reference elements, especially when dealing with in situ applications.
Innovation Solution
A method and device for in situ calibration of a thermometer using a reference element with a phase transition in the solid phase, allowing for multi-point calibration and validation by adjusting the sensor's characteristic curve based on deviations from phase transition temperatures, with the aid of a dynamic heat flow model to account for thermal equilibrium and environmental influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate comparative measurements are used for calibration, then calibration accuracy can be achieved, but the process becomes cumbersome and time-consuming
Solution Approach 1:
The patent combines the calibration reference element and the temperature sensor into a single integrated thermometer device, eliminating the need for separate comparative measurements. The reference element with known phase transition temperatures is integrated directly with the temperature sensor, allowing calibration to occur in-situ during normal operation rather than requiring removal and separate measurement procedures.
Solution Approach 2:
The thermometer performs self-calibration by utilizing its own integrated reference element that exhibits predictable phase transitions at known temperatures. The device automatically detects these phase transitions and uses them to校准 the temperature sensor without requiring external calibration equipment or separate measurement procedures, making the calibration process self-service and eliminating time loss.
2Ease of operation
If reference elements are used for in-situ calibration, then calibration can be performed in operation, but aging effects and sensor drift reduce reliability
Solution Approach 1:
The patent utilizes phase transitions of a reference material (such as ferroelectric or ferromagnetic materials) that occur at precise, well-defined temperatures. These phase transitions serve as inherent calibration markers that are physically determined by the material properties rather than by sensor characteristics. Since phase transition temperatures are fundamental material properties that do not drift with aging, this approach maintains high reliability while enabling in-situ calibration during operation.
Solution Approach 2:
The patent changes the calibration reference from sensor-based references (which drift) to material-property-based references (phase transition temperatures). By monitoring physical parameter changes (phase transitions) of a reference material rather than relying on the stability of reference sensor elements, the system achieves calibration stability that is immune to aging effects and sensor drift.
3Adaptability or versatility
If multiple reference elements with different materials are used, then multi-point calibration is possible, but device complexity increases
Solution Approach 1:
The patent makes a single reference element multi-functional by selecting materials that exhibit multiple phase transitions at different temperatures within the operating range. A ferroelectric or ferromagnetic reference material can provide multiple calibration points (e.g., different Curie temperatures or phase transition points) without requiring multiple separate reference elements, thus achieving multi-point calibration capability while minimizing device 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
Enables simple, accurate in situ calibration and validation of thermometers, reducing errors and measurement inaccuracies by using phase transitions in materials like ferroelectric or ferromagnetic materials, and correcting for dynamic heat flow effects, thus maintaining calibration stability and accuracy.
Implementation Method 1
at least one reference element, which reference element consists at least partially of a material for which, within the temperature range relevant for the operation of the thermometer, at least one phase transition occurs at at least one predetermined phase transition temperature
Data Source
Figure 1
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AI summary
The present invention relates to a method for the in-situ calibration and/or validation of a thermometer (1), having at least one temperature sensor (7) and at least one reference element (8), which reference element (8) consists at least partially of a material for which at least one phase transition occurs at at least one predefined phase transition temperature (TPh) within the temperature range relevant for the use of the thermometer (1), during which phase transition the material remains in the solid phase. The invention also relates to a device for carrying out the method. The method comprises the following steps: detecting and/or recording at least one measured value (Tm) obtained by the temperature sensor (7), in particular as a function of time (Tm(t)); detecting and/or recording at least one characteristic physical or chemical reference variable (G) of the reference element (8), in particular as a function of time (G(t)); detecting the occurrence of the phase transition using a change, in particular a sudden change, in the reference variable (G); establishing a phase transition time point (tPh) at which the phase transition has occurred; determining a sensor temperature (Tm) from a measured value obtained by the temperature sensor (7) at a measurement time point (tm) which has the shortest time interval from the phase transition time point (tPh); and comparing the sensor temperature (Tm) with the phase transition temperature (Tph) and/or determining a deviation (ΔΤ) which may be present between the sensor temperature (Tm) and the phase transition temperature (Tph).