Electrochemical Oxygen Sensor Venting and Wicking Against Spiking
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Solution Overview
Problem
Electrochemical gas sensors, particularly oxygen sensors, face issues such as instability due to gas bubbles forming in the electrolyte, leading to false readings and corrosion, and the presence of inert gases like nitrogen can enhance oxygen diffusion, causing spiking failures across varying temperatures.
Innovation Solution
The design incorporates a stacked electrochemical gas sensor with a separator and breather tab to control oxygen concentration, using a gas diffusion membrane and wicking channels to maintain electrolyte contact, and a planar separator geometry to manage reactant gradients and prevent gas phase diffusion to the sensing electrode, while a breather tab allows venting of gases within the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the sensor operates at elevated temperatures, then the response time improves, but gas bubbles form in the electrolyte causing signal instability
Solution Approach 1:
The patent extracts and removes gas bubbles from the electrolyte using a wick structure that draws bubbles away from the sensing electrode through capillary action, preventing bubble accumulation and signal instability while maintaining elevated operating temperatures for fast response
Solution Approach 2:
The wick structure acts as an intermediary component between the electrolyte and the sensing electrode, mediating the removal of gas bubbles and preventing direct contact between bubbles and the electrode surface, thus maintaining signal stability
2Adaptability or versatility
If inert gas such as nitrogen is present in the sensor, then gas phase diffusion path is created, but oxygen diffusion rate increases causing spiking failures
Solution Approach 1:
The patent removes inert gases and gas phase diffusion paths from the sensor structure by using a sealed design where the sensing electrode is in direct contact with the electrolyte without headspace, eliminating the gas phase pathway that would allow rapid oxygen diffusion and spiking failures
Solution Approach 2:
The patent uses a thin film electrolyte layer that directly contacts the sensing electrode, creating a barrier that prevents gas phase diffusion while allowing ionic conduction, thus blocking the rapid oxygen transport pathway through inert gases
3Reliability
If the electrolyte volume is increased, then bubble formation is reduced, but the sensor size increases
Solution Approach 1:
The patent extracts and removes gas bubbles from the electrolyte using a wick structure, allowing the use of minimal electrolyte volume while preventing bubble accumulation, thus maintaining reliability without increasing sensor size
Solution Approach 2:
The patent uses a porous wick material that provides large surface area and capillary action for bubble removal, enabling effective bubble management with small electrolyte volumes and compact sensor dimensions
4Speed
If the sensing electrode is exposed to gas phase, then oxygen diffusion is rapid, but signal stability decreases due to bubble diffusion
Solution Approach 1:
The patent uses a thin film electrolyte layer that directly contacts the sensing electrode, creating a barrier that prevents gas phase diffusion while allowing controlled ionic transport, thus blocking rapid oxygen transport through gas phase and maintaining signal stability
Solution Approach 2:
The electrolyte thin film acts as an intermediary between the gas environment and the sensing electrode, mediating oxygen transport through ionic conduction rather than gas phase diffusion, thus controlling the diffusion rate and maintaining signal stability
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 improves the sensor's resistance to spiking failures by limiting oxygen diffusion to the sensing electrode, maintaining stable readings across a broad temperature range and preventing corrosion, thereby enhancing the accuracy and reliability of gas concentration measurements.
Implementation Method 1
wicking channels to maintain electrolyte contact
Implementation Method 2
gas diffusion membrane
Implementation Method 3
breather tab allows venting of gases within the sensor
Implementation Method 4
planar separator geometry to manage reactant gradients and prevent gas phase diffusion to the sensing electrode
Data Source
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AI summary
An electrochemical sensor comprising a housing defining a reservoir; a sensing electrode; a counter electrode; at least one separator retaining an electrolyte, wherein the electrolyte provides an ionically conductive pathway between each of the sensing electrode and the counter electrode within the housing; and a plurality of channels located on the interior of the reservoir, operable to transport electrolyte from the reservoir into the separator.