Ion Exchange Sensor for Breath Water Vapor Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sensors for monitoring carbon dioxide in exhaled breath, particularly for tidal breathing, face challenges with high temperature requirements, low sensitivity, and slow response times, often relying on liquid electrolytes or high temperature catalytic methods, which are impractical for ambient conditions and frequent maintenance.
Innovation Solution
A sensor with gold electrodes and a layer of ion exchange material, such as Nafion, that hydrates to form an electrical contact upon exposure to water vapor in exhaled breath, allowing for direct measurement of water vapor concentration without the need for liquid electrolytes or high temperatures, using a conduit to channel exhaled breath and direct air onto the sensing element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature catalytic reduction methods are used to detect carbon dioxide, then detection capability is achieved, but response time becomes slow and the system becomes cumbersome
Solution Approach 1:
The invention changes the operating temperature parameter from high temperature (300-400°C) to ambient temperature, enabling fast response times while maintaining detection capability through a different detection mechanism based on water vapor measurement
Solution Approach 2:
The invention replaces the mechanical/thermal catalytic reduction system with an electrochemical sensor system that measures water vapor concentration, eliminating the need for high temperature heating elements and complex catalytic converters
2Reliability
If liquid electrolyte sensors are used for carbon dioxide detection, then measurement capability is achieved, but the sensor requires frequent maintenance and has long response time
Solution Approach 1:
The invention changes the physical state of the electrolyte from liquid to solid (Nafion membrane), eliminating evaporation and contamination issues that require frequent maintenance while maintaining ion conduction capability
Solution Approach 2:
The solid electrolyte membrane is a durable, maintenance-free component that replaces the fragile liquid electrolyte system, significantly extending sensor lifespan and reliability
3Adaptability or versatility
If a semi-permeable membrane is used to bound the liquid electrolyte, then gas permeability is achieved, but water evaporation is impeded and response time increases
Solution Approach 1:
The invention extracts the liquid electrolyte from the system and replaces it with a solid membrane, eliminating the need for a semi-permeable membrane while maintaining gas permeability and improving response time
Solution Approach 2:
The Nafion membrane is a thin, flexible solid film that allows rapid gas diffusion and ion transport, providing both gas permeability and fast response time without the constraints of liquid electrolyte containment
4Measurement precision
If solid electrolyte sensors operating at high temperature are used, then carbon monoxide detection sensitivity is improved, but the sensor becomes impractical for ambient conditions
Solution Approach 1:
The invention changes the operating temperature parameter from high temperature (300-400°C) to ambient temperature, making the sensor practical for portable and wearable applications while maintaining detection sensitivity through water vapor measurement
Solution Approach 2:
Instead of directly measuring carbon dioxide or carbon monoxide at high temperature, the invention inverts the approach by measuring water vapor concentration at ambient temperature, which correlates with respiratory gas composition
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 provides a compact, simple, and accurate measurement of water vapor concentration in exhaled breath, enabling efficient monitoring of lung function and early detection of respiratory issues like asthma, without the need for heating or cooling, with improved response times and reduced maintenance.
Implementation Method 1
a layer of ion exchange material extending between the working electrode and the counter electrode whereby contact of the ion exchange layer with water vapour in exhaled breath forms an electrical contact between the working and counter electrodes
Implementation Method 2
contact of the ion exchange layer with water vapour in exhaled breath forms an electrical contact
Data Source
Figure 1a~1c
Figure 2
Figure 3
AI summary
The present invention provides a sensor (2) for sensing water vapour in exhaled breath, the sensor comprising: a sensing element (8, 40) disposed to be exposed to the exhaled breath, the sensing element comprising: a working electrode (12, 44);a counter electrode (14, 46); and a layer of ion exchange material (48) extending between the working electrode and the counter electrode; whereby, when in use, contact of the ion exchange layer with water vapour in exhaled breath forms an electrical contact between the working and counter electrodes and the output of the sensor can be used to generate a display representative of the change in concentration of water vapour over time in a breath exhalation.