Dual Temperature Sensor Layout for Thick-Film Liquid Heaters

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Solution Overview

Problem

Existing heating devices require multiple coating steps due to the use of different materials for temperature sensors and heating conductors, leading to complex and unreliable constructions.

Innovation Solution

A heating device with a carrier having heating conductors and two temperature sensors, where the first sensor is closely positioned to monitor the heating conductor temperature and the second sensor is farther away to measure the medium temperature, allowing for efficient temperature detection and prevention of overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If two different coating steps are used for temperature sensors and heating conductors, then both components can be applied to the carrier, but the construction becomes complex and reliability decreases

Engineering Contradiction:
Improvecoating process simplicityVSAvoidheating device reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies both temperature sensors and heating conductors using the same thick-film technology on the ceramic carrier, eliminating the need for two different coating steps. This homogeneous manufacturing approach simplifies the process while improving reliability by reducing interface complexities between different material layers.

Inventive Principle:
Principle #33Homogeneity

2Measurement precision

If the first temperature sensor is positioned close to the heating conductor, then direct temperature monitoring is achieved, but electrical insulation distance requirements must be carefully observed

Engineering Contradiction:
Improveheating conductor temperature detection accuracyVSAvoidinsulation design complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a ceramic carrier as an intermediary substrate between the heating conductor and the first temperature sensor. This ceramic material provides inherent electrical insulation properties, allowing the temperature sensor to be positioned close to the heating conductor for accurate temperature monitoring while automatically satisfying electrical insulation requirements without additional complex insulation structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If the second temperature sensor is positioned at a greater distance from the heating conductor, then medium temperature measurement is improved, but the sensor arrangement becomes more spread out

Engineering Contradiction:
Improvemedium temperature detection accuracyVSAvoidcarrier surface area occupied
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent arranges the second temperature sensor at a greater distance from the heating conductor along the flow direction of the medium, utilizing the longitudinal dimension of the carrier rather than spreading components across the surface area. This dimensional arrangement allows accurate medium temperature measurement while maintaining a compact overall device footprint.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration enables direct monitoring of heating conductor temperature and minimizes environmental influence, ensuring safe and reliable operation by initiating countermeasures when high temperatures are detected, while also simplifying the construction process.

Implementation Method 1

heating conductors being applied to the carrier... the heating device to heat the medium or a liquid

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the first temperature sensor is arranged close to the heating conductor... the temperature at the first temperature sensor is also essentially influenced by the heating conductor

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

the second temperature sensor is at a greater distance from the heating conductor... its temperature is essentially determined by the medium to be heated

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2693835B1Heating device and electric device with a heating device
Publication Date: 2016.03.23 E G O ELEKTRO GERAETEBAU GMBH
  • EP2693835B1 patent drawingFigure 1~2
  • EP2693835B1 patent drawingFigure 3~4
  • EP2693835B1 patent drawingFigure 5

AI summary

A heating device for heating a liquid in the flow has a carrier with heating conductors on it and at least two SMD temperature sensors. A first temperature sensor is arranged close to the heating conductor at a distance of less than twice the width of the heating conductor. A second temperature sensor has a greater distance from the heating conductor than the first temperature sensor, preferably more than twice the distance of the first temperature sensor from the heating conductor.