Diagnostic Thermometer Using Thermal Coupling Feedback

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Solution Overview

Problem

Existing temperature sensors in process automation suffer from significant measurement distortions due to unwanted temperature gradients and thermal resistances, leading to inaccurate temperature readings, which are exacerbated by factors like thermal couplings, corrosion, and dynamic environmental changes.

Innovation Solution

A device and method that determine the thermal coupling between the sensor and the medium, using a differential temperature sensor and a diagnostic unit to correct for heat conduction effects and temperature gradients, allowing for continuous monitoring and correction of measurement deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the protective tube and measuring insert are made longer to improve thermal coupling, then measurement accuracy improves, but response time deteriorates due to increased thermal mass and heat conduction path length

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidresponse time
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent divides the temperature sensor into multiple sensing elements positioned at different locations along the measuring insert. This segmentation allows the system to capture temperature gradients and calculate the true medium temperature through evaluation algorithms, resolving the contradiction by achieving accurate measurements without requiring excessive thermal coupling length.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a feedback mechanism where the evaluation unit continuously processes temperature signals from multiple sensor elements, determines thermal coupling conditions, and corrects measurements in real-time. This feedback loop enables accurate temperature determination while maintaining fast response times by dynamically compensating for thermal resistance effects.

Inventive Principle:
Principle #23Feedback

2Speed

If the protective tube is made shorter to improve response time, then response time improves, but measurement accuracy deteriorates due to insufficient thermal equilibrium

Engineering Contradiction:
Improveresponse timeVSAvoidtemperature measurement accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

By using multiple temperature sensor elements at different positions along the shortened protective tube, the system can detect temperature gradients and use evaluation algorithms to determine the true medium temperature, achieving accurate measurements even with reduced thermal coupling length.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The evaluation unit provides real-time feedback by processing signals from multiple sensor elements, determining thermal coupling status, and correcting measurements to compensate for insufficient thermal equilibrium, enabling accurate readings with shorter protective tubes.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If additional temperature sensor elements are added to improve measurement accuracy, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidsensor and electronics complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent designs the evaluation unit to perform multiple functions: processing signals from multiple sensor elements, determining thermal coupling conditions, calculating correction factors, and outputting corrected temperature values. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while achieving improved measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Measurement precision

If thermal coupling is increased to reduce measurement deviations, then measurement precision improves, but heat conduction losses increase

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidheat conduction loss
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The evaluation unit continuously monitors temperature signals and determines thermal coupling conditions, then applies correction factors to compensate for heat conduction losses. This feedback mechanism enables accurate temperature measurement without requiring excessive thermal coupling that would cause significant energy losses.

Inventive Principle:
Principle #23Feedback

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

Enhances measurement accuracy by directly determining and correcting for thermal coupling and heat transfer dynamics, reducing measurement errors and improving the reliability of temperature readings.

Implementation Method 1

a temperature sensor for detecting the temperature and determined on the basis of the output signal of the temperature sensor

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

determine a thermal coupling between the device and the medium

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP4264213B1Thermometer having a diagnostic function
Publication Date: 2026.01.07 ENDRESS & HAUSER GMBH & CO KG
  • EP4264213B1 patent drawingFigure 1a~1b
  • EP4264213B1 patent drawingFigure 2a~2b
  • EP4264213B1 patent drawingFigure 3a~3c

AI summary

The present invention relates to a device (1) for determining and/or monitoring the temperature (T) of a medium (M), comprising a temperature sensor (5) for detecting the temperature (T) and electronics (4), wherein the temperature sensor (5) comprises a temperature-sensitive sensor element (13) that is in electrical contact with the electronics (4) by way of at least one connection line (6). The invention furthermore relates to a method for operating a corresponding device (1). The device (1) comprises a diagnostic unit (9) that has an apparatus (9a) for varying a power (P) of an input signal (E) over time, said input signal being able to be applied to the temperature sensor (5) or at least one component of the device (1), and which diagnostic unit (9) is designed so as, based on an output signal (A) from the temperature sensor (5) in response to the input signal (E), to ascertain a statement regarding thermal coupling of the device (1) to the medium (M).