Electrochemical Gas Sensor with BaCO3 Absorbent Housing

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Solution Overview

Problem

Existing electrochemical gas sensors face challenges in achieving high measurement sensitivity and signal stability, particularly when detecting acid gases like hydrogen halides, due to issues such as cross-sensitivity to other gases and electrode material degradation.

Innovation Solution

An electrochemical gas sensor design featuring a housing with absorbent composition, including BaCO3, that captures reaction products, preventing their accumulation and ensuring continuous operation, combined with a specific electrolyte composition for enhanced detection of acidic gases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional electrochemical sensors are used for detecting acid gases, then basic detection function is achieved, but measurement sensitivity and signal stability deteriorate due to cross-sensitivity and electrode degradation

Engineering Contradiction:
Improvemeasurement sensitivityVSAvoidsignal stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

An absorbent composition is introduced as an intermediary substance between the gas phase and the electrodes. This composition selectively absorbs acid gases (HF, HCl, H2S) from the gas stream, preventing them from reaching and degrading the electrodes while still allowing the sensor to detect the gas presence and concentration through the electrochemical reaction in the electrolyte.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The absorbent composition is placed specifically in the gas inlet region and around the electrodes, creating a localized protective environment. This localized application allows the sensor to maintain high sensitivity in the detection zone while protecting vulnerable components from harmful gas exposure.

Inventive Principle:
Principle #3Local quality

2Duration of action of stationary object

If electrodes are exposed to acid gases for continuous detection, then continuous monitoring capability is achieved, but electrode material degrades and sensor fails

Engineering Contradiction:
Improvecontinuous operation timeVSAvoidsensor failure risk
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The absorbent composition is positioned in advance in the gas inlet path and around the electrodes to cushion them against acid gas exposure. This protective layer absorbs the harmful gases before they can contact and degrade the electrode materials, enabling continuous operation without sensor failure.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The absorbent composition serves as a protective intermediary that stands between the acid gases and the electrodes. It selectively binds the harmful gases through absorption, preventing direct contact with the electrode materials and thus preventing degradation and failure during continuous operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If reaction products accumulate on electrodes during continuous operation, then detection function continues, but signal drift increases and accuracy decreases

Engineering Contradiction:
Improvecontinuous detection capabilityVSAvoidsignal stability
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The absorbent composition continuously extracts reaction products (such as metal halides formed at the electrodes) from the electrolyte and gas phases. By removing these accumulating substances, the system maintains stable electrochemical conditions at the electrodes, preventing signal drift and maintaining detection accuracy during continuous operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The absorbent composition continuously removes reaction products from the sensor system, effectively discarding substances that would otherwise accumulate and cause signal drift. This continuous removal process maintains the integrity of the electrochemical reactions and ensures stable, drift-free signals over extended operation periods.

Inventive Principle:
Principle #34Discarding and recovering

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 sensor achieves high measurement sensitivity and stability, effectively preventing the release of toxic gases and reducing signal drift during continuous exposure to acidic gases, ensuring accurate and reliable detection.

Implementation Method 1

the counter electrode and/or the housing consists at least partially of an absorbent composition, wherein the absorbent composition contains BaCO3 as an absorbent

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

They usually have several electrodes that are in conductive contact with an electrolyte liquid and in this way form a galvanic element - also referred to below as an electrochemical measuring cell

Methodology Applied
Scientific EffectElectrochemical reaction: Redox Reactions

Implementation Method 3

For the purposes of the present invention, acidic gases are generally understood to mean gases that form (weak) acids when dissolved in water

Methodology Applied
Scientific EffectDissolution: Solvation

Data Source

PatentEP3108226B1Electrochemical gas sensor
Publication Date: 2022.07.27 DRAGER SAFETY AG & CO KAAA
  • EP3108226B1 patent drawingFigure 1a~1c
  • EP3108226B1 patent drawingFigure 2a~2c
  • EP3108226B1 patent drawingFigure 3a~3c

AI summary

The invention relates to an electrochemical gas sensor (10) comprising a housing (11) which has a number of electrodes (31, 32), i.e. at least one working electrode (31) and at least one counter electrode (32), in additon to a liquid electrolyte (60), at least one of said electrodes (31, 32) and/or the housing (11) consisting at least partially of an absorption agent composition. The invention also relates to the use of a sensor of this type for detecting acid gases.