Electronic Nose Gas Composition Detection with Environmental Conditioning
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Solution Overview
Problem
Existing electronic noses for gas mixture analysis are highly sensitive to temperature and humidity changes, leading to imprecise and unreliable measurements due to their dependence on environmental conditions and the use of active carbons, which alter relative humidity.
Innovation Solution
A device that regulates temperature and humidity using a conditioning system, mixing unknown gas mixtures with a cleaning gas to maintain a constant state, allowing for precise and repeatable measurements by calibrating sensors with a known gas mixture and analyzing the unknown mixture in a controlled environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electronic noses use sensors to detect gas components, then they can analyze and classify air composition, but the measurements become highly sensitive to temperature and humidity changes, reducing reliability
Solution Approach 1:
The patent applies parameter changes by actively controlling and stabilizing the temperature and humidity parameters of the reference gas and sensing chamber environment. The system uses temperature and humidity sensors combined with heating elements and humidification systems to maintain constant environmental parameters, thereby eliminating the sensitivity of sensor measurements to environmental variations and improving both precision and reliability
Solution Approach 2:
The patent creates an inert-controlled atmosphere in the sensing chamber by introducing a reference gas with stabilized temperature and humidity parameters. This controlled inert environment isolates the sensors from uncontrolled environmental variations, allowing accurate detection of gas composition changes without interference from temperature and humidity fluctuations
2Measurement precision
If active carbons are used to clean reference gas, then odourless reference air is obtained, but the relative humidity of the gas changes, affecting measurement accuracy
Solution Approach 1:
The patent implements feedback control by using humidity sensors to continuously monitor the humidity of the reference gas after it passes through the active carbon filter. The system adjusts humidification parameters based on this feedback to maintain constant humidity levels, thereby compensating for humidity changes caused by the active carbon cleaning process while preserving gas purity
Solution Approach 2:
The patent introduces an intermediary humidification system between the active carbon filter and the sensing chamber. This intermediary component adds moisture to the reference gas to compensate for humidity removal by the active carbon, ensuring that the final reference gas has both high purity and stable humidity without directly modifying the active carbon filter itself
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
Enables precise and repeatable detection of gas mixtures independent of climatic conditions, improving the reliability and accuracy of electronic nose measurements.
Implementation Method 1
The principle on which these sensors are based is the variation in the electrical conductivity of the oxide in the presence of odoriferous substances compared to the value of this parameter under reference conditions
Implementation Method 2
a conditioning system (18) designed to regulate a temperature and a humidity of the cleaning gas mixture (Mp) and, hence, a temperature and a humidity of the known gas mixture (Mn) and of the unknown gas mixture (Minc)
Implementation Method 3
a condenser (30) arranged to condense a water vapour in the cleaning gas mixture (Mp) to a desired extent
Implementation Method 4
an evaporating chamber (28) arranged to evaporate a water in the evaporating chamber (28) to a desired extent
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A method for detecting the composition of an unknown gas mixture (Minc) through an electronic nose (2) equipped with a measuring chamber (3) that houses at least one sensor comprises the steps of: calibrating a sensor by feeding a known gas mixture (Mn) into the measuring chamber (3); feeding the unknown gas mixture (Minc) into the chamber (3), while keeping the unknown gas mixture (Mine) in a predetermined desired state; and detecting the composition of the unknown gas mixture (Minc) by means of the sensor.