Multi-Detector Gas Sensor for Selective Food Ripening 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, leading to crosstalk between target gases and difficulty in detecting gases at ppm levels or lower, which hampers accurate identification of food ripening or spoilage.
Innovation Solution
A gas sensor with multiple detectors discolored by reacting with different target gases, utilizing pH indicators and hydrophilic membranes, and a hydrophobic base for gas permeation, capable of independently detecting gases like hydrogen sulfide, ammonia, and carbon dioxide, with an image detector to analyze color changes and transmit data for determining food type and state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional gas sensors (semiconductor or electrochemical) are used to measure gas density, then the sensor can detect the presence of target gas, but measurement selectivity deteriorates due to crosstalk where target gas and other gases are simultaneously measured
Solution Approach 1:
The gas sensor is divided into multiple independent detectors, each equipped with specific pH indicators that react selectively to different target gases. This segmentation allows each detector to independently measure specific gas types without interference from other gases, thereby improving measurement selectivity while maintaining detection capability
Solution Approach 2:
Each detector is assigned a specific pH indicator with distinct chemical properties tailored to detect particular gases. The local quality of each detector is optimized through selective indicator placement, enabling differentiated response to different target gases and eliminating crosstalk between measurements
2Measurement precision
If conventional gas sensors are used to measure low concentration gases, then the sensor structure remains simple, but measurement sensitivity deteriorates making it difficult to measure gases at ppm level or lower
Solution Approach 1:
The sensor is segmented into multiple detectors, each specialized for detecting specific low concentration gases through pH indicators with high sensitivity. This segmentation enables each detector to focus on detecting trace amounts of its target gas without being overwhelmed by other gas components, achieving ppm-level or lower detection sensitivity
Solution Approach 2:
The invention utilizes pH parameter changes as the detection mechanism. pH indicators undergo distinct color changes in response to minute pH variations caused by low concentration target gases, enabling highly sensitive detection of trace gas amounts while maintaining a relatively simple sensor structure
3Adaptability or versatility
If multiple pH indicators are used in detectors to improve selectivity, then the ability to independently detect different target gases improves, but device complexity increases
Solution Approach 1:
Instead of placing multiple pH indicators in a single detector, the invention segments the sensor into multiple detectors, each containing a specific pH indicator. This segmentation approach achieves multi-gas detection capability while keeping each detector's composition simple and manageable
Solution Approach 2:
The array of detectors with different pH indicators collectively provides universal detection capability for multiple target gases. Each detector performs a specialized function, but together they create a multi-functional system capable of independently detecting various gases without requiring complex individual detector designs
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, improving selectivity and sensitivity to ppm levels, allowing for accurate identification of food types and ripening states, and enabling temperature control in refrigeration based on gas sensor data.
Implementation Method 1
each of the plurality of detectors is discolored by reacting with each predetermined target gas
Implementation Method 2
pH variation generated by reacting with a predetermined target gas
Implementation Method 3
The base may include a hydrophobic membrane needed for gas permeation
Implementation Method 4
The base may include a hydrophobic membrane needed for gas permeation
Implementation Method 5
The detector may include a hydrophilic membrane having a detection solution
Data Source
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.