Dual-Sensing Electrochemical Sensor for Catalyst Deactivation Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrochemical gas sensors face challenges in maintaining accuracy and reliability due to catalyst deactivation and contamination, especially when detecting low global warming potential refrigerants, which can result in false alarms and undetected leaks, as traditional sensors lack the ability to selectively identify gas species and detect deactivation effectively.
Innovation Solution
The implementation of a dual-sensing element system with a protective feature that prevents non-target gases from contacting the second sensing element, allowing for state of health monitoring and restoration protocols, including the application of a pulse voltage to restore the sensing capability when contamination is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single sensing element is used to detect target gas, then the device complexity is low, but the reliability of detection is reduced due to inability to detect catalyst deactivation
Solution Approach 1:
The sensing system is divided into two separate sensing elements: a first sensing element exposed to all gases for detecting both target gas and contaminants, and a second sensing element protected by a selective barrier that allows only target gas to reach it. This segmentation enables comparison between the two elements to detect catalyst deactivation caused by non-target species.
2Reliability
If activated carbon is used to protect the sensing element, then the sensor is protected from poisoning, but the detectability of target gas is reduced when the target species adsorbs on the adsorbent
Solution Approach 1:
A selective barrier is introduced as an intermediary layer between the contaminant and the sensing element. This barrier selectively blocks non-target gases while allowing target gas molecules to pass through, thus protecting the catalyst without interfering with target gas detection.
3Reliability
If the sensing element is continuously monitored for contamination, then the state of health can be detected, but the device complexity increases
Solution Approach 1:
The system continuously compares the output signals from the first sensing element (exposed to all gases) and the second sensing element (protected by selective barrier). When a discrepancy is detected indicating catalyst deactivation, the system generates a signal to indicate the compromised state of health, providing real-time feedback without complex additional monitoring equipment.
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 approach enables efficient state of health monitoring and restoration of electrochemical sensors, reducing false alarms and ensuring continuous detection of target gases by identifying and mitigating catalyst deactivation, thereby enhancing the reliability of leak detection for flammable refrigerants.
Implementation Method 1
Electrochemical gas sensors are gas detectors that measure a concentration of a target gas by oxidizing or reducing the target gas at an electrode and measuring the current that is generated
Implementation Method 2
Electrochemical gas sensors are gas detectors that measure a concentration of a target gas by oxidizing or reducing the target gas at an electrode and measuring the current that is generated
Implementation Method 3
Passive fault mitigation methods such as adsorption by activated carbon have been used successfully to protect CO sensors from poisoning
Implementation Method 4
This is normally achieved by using a capillary or membrane, which limits gas access in a well-defined and repeatable way
Data Source
AI summary
A method of manufacturing an electrochemical sensing system is provided. The method includes forming a sensor with a first sensing element disposed on a sensor, the first sensing element configured to detect a target gas, disposing a second sensing element on the sensor, the second sensing element configured to detect the target gas, and coupling a protective feature to the second sensing element, the protective feature configured to prevent non-target gases from contacting the second sensing element. The sensor is configured such that if the first sensing element generates a current exceeding a first threshold current value and the second sensing element does not exceed a second threshold current value it is determined that the first sensing element is contaminated and a restoration protocol is performed on the first sensing element.