Electrochemical Sensor Reference Electrode Contamination Cleaning

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Solution Overview

Problem

Electrochemical sensors with two electrodes experience potential drift due to polarization, leading to non-linear patterns when detecting high gas concentrations, which can be exacerbated by environmental changes, volatile organic compounds, and contamination, causing reduced sensitivity and potential sensor failure.

Innovation Solution

Incorporating a third reference electrode and using cyclic voltammetry (CV) scans to identify and clean contamination on the reference electrode, ensuring it returns to its normal potential state, thereby maintaining sensor linearity and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a two-electrode electrochemical sensor is used, then the device complexity is low, but the measurement precision deteriorates due to potential drift and polarization

Engineering Contradiction:
Improvenumber of electrodesVSAvoidgas concentration detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The sensor is segmented into three separate electrodes (working electrode, reference electrode, and counter electrode) instead of using a two-electrode configuration. This segmentation allows the reference electrode to be dedicated solely to providing a stable potential reference, while the working electrode focuses on gas detection and the counter electrode handles balancing reactions. This division of functions eliminates the potential drift and polarization issues that plague two-electrode systems, thereby improving measurement precision without significantly increasing overall device complexity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the sensor operates in challenging environments with contamination and environmental changes, then the sensor must maintain reliability, but the measurement precision deteriorates due to contamination and polarization

Engineering Contradiction:
Improvesensor operation stabilityVSAvoidgas concentration detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The reference electrode provides continuous feedback on the electrochemical cell's potential state. By monitoring the reference electrode's potential, the system can detect shifts caused by contamination or environmental changes. This feedback mechanism enables the system to compensate for drift and maintain measurement precision even in challenging environments, thereby resolving the contradiction between reliability and measurement precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention changes the electrochemical parameters by introducing a stable reference electrode with a fixed, known potential. This parameter change (adding a constant reference potential) allows the system to compensate for variable conditions such as temperature changes and contamination. The reference electrode's stable potential serves as an anchor point, enabling the system to maintain measurement accuracy despite environmental variations and contamination.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If high gas concentrations are detected, then the sensor's detection range is sufficient, but the measurement precision deteriorates due to non-linear patterns from polarization

Engineering Contradiction:
Improvegas concentration rangeVSAvoiddetection linearity
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The reference electrode acts as an intermediary that mediates the potential relationship between the working and counter electrodes. By introducing this intermediate reference point with a stable, known potential, the system can accurately measure gas concentrations across a wide range without the non-linear polarization effects that occur in two-electrode systems. The reference electrode decouples the potential control function from the detection function, maintaining linearity even at high gas concentrations.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The solution effectively stabilizes the reference electrode potential, enhancing the sensor's ability to detect gas concentrations accurately by reducing the impact of contamination and environmental factors, ensuring reliable operation even in challenging work environments.

Implementation Method 1

scanning a reference electrode using a first cyclic voltammetry (CV) scan to generate a first set of readings

Methodology Applied
Scientific EffectCyclic voltammetry:

Implementation Method 2

the reference electrode is scanned again using a second CV scan... rapid cleaning of the reference electrode is carried out using a third CV scan

Methodology Applied
Scientific EffectCyclic voltammetry cleaning:

Implementation Method 3

The target gas is reacted at this electrode while a balancing reaction takes place at the counter electrode. The gas reacts at the electrode and affects the electrical output of the sensor.

Methodology Applied
Scientific EffectElectrochemical reaction:

Data Source

PatentEP3507597B1System and method for identifying and cleaning contamination of an electrochemical sensor
Publication Date: 2024.05.08 HONEYWELL INTERNATIONAL INC
  • EP3507597B1 patent drawingFigure 1
  • EP3507597B1 patent drawingFigure 2~3
  • EP3507597B1 patent drawingFigure 4~5

AI summary

Methods and systems for identifying contamination of an electrochemical sensor (10) and cleaning the electrochemical sensor (10) are provided. A method may comprise scanning the sensor (10) for the first time using CV to generate a reference set of readings; scanning the sensor (10) for the second time after the sensor (10) has been employed; comparing a second set of readings from the second CV scan to the reference set of readings; when the second set of readings is different from the reference set of readings, determining that the sensor (10) potential has shifted; scanning the sensor (10) for the third time to clean one or more elements of the sensor (10); scanning the sensor (10) for the fourth time; comparing a fourth set of readings from the fourth CV scan to the second set of readings; and determining that the potential of the sensor (10) has shifted due to pollution of the sensor (10), and/or that the sensor (10) can be further cleaned.