Corrosion Detection Sensor Using Impedance Segmentation

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Solution Overview

Problem

Existing methods for detecting corrosive factors in circulating liquids of hot water supply and heating systems are not highly accurate, as they can incorrectly identify non-corrosive impurities, leading to incomplete detection of corrosive factors, which can cause corrosion and reduce heat exchange performance.

Innovation Solution

An anticorrosion performance degradation detection device using a detection electrode, counter electrode, power supply, and sensor that applies AC and DC voltages to measure impedance changes in different frequency ranges, allowing for the differentiation between corrosive and non-corrosive impurities by decomposing and reforming the electrode surface coating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If impedance measurement is used to detect corrosive factors, then detection capability is improved, but measurement precision deteriorates due to inability to distinguish corrosive from non-corrosive impurities

Engineering Contradiction:
Improvedetection capabilityVSAvoidprecision
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The impedance spectrum is segmented into multiple frequency ranges (low, medium, high frequencies), and the detection method selectively uses impedance values from low and medium frequency ranges to distinguish corrosive impurities from non-corrosive ones, thereby improving measurement precision while maintaining detection capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method changes the parameter of frequency selection by excluding high frequency impedance values and focusing on low and medium frequency ranges. This parameter change enables differentiation between corrosive and non-corrosive impurities, resolving the precision issue

Inventive Principle:
Principle #35Parameter changes

2Loss of substance

If corrosion inhibitor concentration is reduced due to long-term use, then cost is reduced, but reliability deteriorates due to degradation of anticorrosion performance

Engineering Contradiction:
Improvecorrosion inhibitor concentrationVSAvoidanticorrosion performance
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The patent implements a feedback mechanism by continuously monitoring the impedance spectrum of the circulating liquid and comparing it against reference values. When changes indicate corrosive impurity detection, the system provides feedback to maintain or adjust corrosion inhibitor concentration, ensuring reliability while optimizing substance usage

Inventive Principle:
Principle #23Feedback

3Device complexity

If conventional impedance measurement is used, then device complexity is reduced, but measurement precision deteriorates due to false detection of non-corrosive impurities

Engineering Contradiction:
ImprovesimplicityVSAvoidprecision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The measurement approach is segmented by frequency range, selectively using only low and medium frequency impedance values while excluding high frequency values that cause false detections. This segmentation maintains relative simplicity while significantly improving precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method changes the measurement parameters by focusing on specific frequency ranges (low and medium) and excluding others (high frequency). This parameter optimization reduces false detections from non-corrosive impurities while maintaining device simplicity

Inventive Principle:
Principle #35Parameter changes

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 earlier, more accurate, and sensitive detection of corrosive factors, preventing corrosion and maintaining heat exchange performance by distinguishing between corrosive and non-corrosive impurities in the circulating liquid.

Implementation Method 1

a detection electrode (1), on which a corrosion inhibitor reacts to form an electrode surface coating

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

a power supply (4), capable of applying an AC voltage and a DC voltage between the detection electrode (1) and the counter electrode (2)

Methodology Applied
Scientific EffectElectrical Impedance: Electrical Resistance

Data Source

PatentEP3032245B1Corrosion-prevention-performance degradation detection sensor, hot water supply and heating system, and facility equipment
Publication Date: 2020.10.07 MITSUBISHI ELECTRIC CORP
  • EP3032245B1 patent drawingFigure 1~2
  • EP3032245B1 patent drawingFigure 3~4
  • EP3032245B1 patent drawingFigure 5~6C

AI summary

An anticorrosion performance degradation detection sensor (10) for detecting inclusion of a corrosive factor in a solvent to which a corrosion inhibitor for inhibiting corrosion of an anticorrosion target material is added includes a detection electrode (1), a counter electrode (2), and a power supply (4). The detection electrode (1) reacts with a corrosion inhibitor dissolved in the solvent to form on a surface thereof an electrode surface coating that inhibits corrosion. The counter electrode (2) is disposed to face the detection electrode (1) with a predetermined distance therebetween. The power supply (4) applies an AC voltage with a predetermined frequency between the detection electrode (1) and the counter electrode (2), and performs a voltage operation that promotes decomposition and reformation of the electrode surface coating. The detection electrode (1) detects inclusion of the corrosive factor in the solvent based on a change in an impedance response by the applied AC voltage with the predetermined frequency before and after the voltage operation that promotes decomposition and reformation of the electrode surface coating.