Multi-Detector Gas Sensor for Selective Food Ripening Gas Detection
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Solution Overview
Problem
Conventional gas sensors face limitations in selectivity and sensitivity, particularly in measuring specific gases at low concentrations, such as those emitted during the ripening process of food, due to crosstalk between target and other gases, and struggle to detect gases at ppm levels or lower.
Innovation Solution
A gas sensor with a plurality of detectors discolored in response to pH variations from reacting with specific target gases, utilizing a hydrophilic membrane and a hydrophobic base for gas permeation, and an image detector to transmit data on color changes, allowing for independent detection of multiple target gases and visual recognition of gas types and states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional gas sensors (semiconductor or electrochemical) are used to measure target gas, then the sensor can detect gas density, but crosstalk occurs where target gas and other gases are simultaneously measured, limiting measurement selectivity
Solution Approach 1:
The gas sensor is divided into multiple detectors, each coated with a different indicator substance that selectively reacts with specific target gases. This segmentation allows each detector to independently measure a specific gas component, eliminating crosstalk and enabling selective measurement of multiple gases simultaneously.
Solution Approach 2:
Each detector is assigned a specific indicator substance with localized chemical properties tailored to detect a particular target gas. This local quality differentiation ensures that each detector responds only to its designated target gas, achieving high measurement selectivity while maintaining the ability to measure multiple gases.
2Measurement precision
If conventional gas sensors are used, then gas measurement is possible, but the measurement sensitivity is less than that of the human olfactory organ, making it difficult to measure gas at ppm level or lower
Solution Approach 1:
The sensor utilizes indicators that undergo color changes in response to pH variations caused by target gas reactions. This parameter change (color) provides a visual and measurable signal that enhances sensitivity, allowing detection of gas concentrations at ppm level or lower, surpassing conventional sensor capabilities.
Solution Approach 2:
The sensor employs indicators that change color when reacting with target gases, providing a visual indication of gas presence and concentration. This color change mechanism significantly enhances measurement sensitivity, enabling detection of trace gases at ppm levels that conventional sensors cannot detect.
3Adaptability or versatility
If multiple detectors are used to detect different target gases independently, then measurement selectivity is improved, but device complexity increases
Solution Approach 1:
Multiple detectors with different indicator substances are merged into a single integrated sensor device. This combining approach maintains high measurement selectivity for multiple target gases while simplifying the overall device structure, allowing simultaneous detection of different gases in one unified sensor system.
Solution Approach 2:
The gas sensor is designed as a universal device capable of detecting multiple different target gases through its array of detectors with various indicator substances. This multi-functionality allows the single sensor to perform selective measurement of multiple gases, reducing the need for multiple separate sensors and thereby simplifying the overall system.
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 independent detection of various target gases, including those emitted during food ripening, with high selectivity and sensitivity, allowing users to intuitively recognize the category and state of food through color changes, and can be integrated into electronic products like refrigerators for temperature control.
Implementation Method 1
utilizing a hydrophilic membrane and a hydrophobic base for gas permeation
Implementation Method 2
at least one pH indicator which is discolored in response to pH variation generated by reacting with a predetermined target gas
Implementation Method 3
The plurality of detectors may include at least one pH indicator which is discolored in response to pH variation generated by reacting with a predetermined target gas
Implementation Method 4
an image detector configured to detect colors of the plurality of detectors
Data Source
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AI summary
A gas sensor includes a plurality of detectors discolored by reacting with different predetermined target gases, such that the gas sensor independently measures the amount of each target gas. A refrigerator for deciding a type and state of target food contained in a container by sensing a color change of a gas sensor mounted to the container including the target food, and a method for controlling the gas sensor are disclosed. The gas sensor for detecting a plurality of target gases includes a base and a plurality of detectors provided at the base. The detectors respectively detect different target gases, and each detector is discolored by reacting with each predetermined target gas.