Disposable pH Test Paper for Water Quality Monitoring
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Solution Overview
Problem
Conventional water quality measurement techniques, particularly glass electrodes, face issues such as susceptibility to acids and alkalis, slow response times, complex maintenance, and limitations in real-time monitoring, along with high manufacturing costs and poor package stability in solution property sensors.
Innovation Solution
A solution property sensor is designed with a substrate hosting temperature, electrical conductivity, and pH value sensing elements, electrically connected to conductive patterns for simultaneous signal transmission, utilizing indium tin oxide for pH sensing and a reference electrode, with a waterproof layer for stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If glass electrode is used for pH measurement, then measurement precision is improved, but device complexity and maintenance difficulty increase
Solution Approach 1:
The patent replaces the complex, maintenance-intensive glass electrode with a simple, disposable pH test paper strip. The test paper is inexpensive, single-use, and eliminates the need for calibration, cleaning, and storage of fragile glass electrodes. Users simply dip the strip into the solution and read the color change, achieving sufficient precision for water quality monitoring without the complexity of traditional electrodes.
Solution Approach 2:
The patent replaces the electrical/mechanical glass electrode system with a chemical/colorimetric test paper system. Instead of measuring electrical potential differences through a glass membrane, the test paper uses pH-sensitive dyes that change color based on hydrogen ion concentration. This substitution eliminates the need for electrical connections, calibration circuits, and fragile glass structures while providing adequate measurement precision for the application.
2Measurement precision
If glass electrode is used for pH measurement, then measurement precision is improved, but response time increases
Solution Approach 1:
The disposable test paper strip provides immediate color change upon contact with the solution, eliminating the slow response time of glass electrodes. The chemical reaction on the test paper surface occurs instantly, allowing users to obtain pH readings within seconds rather than waiting for the electrode to equilibrate, which is particularly advantageous for monitoring rapidly changing water quality conditions.
3Measurement precision
If glass electrode is used for pH measurement, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The test paper strip requires no calibration, cleaning, or special handling procedures. Users simply dip the strip into the water sample and compare the color change to a reference chart. This eliminates the complex operational steps required for glass electrodes, including zero calibration with neutral buffer, sensitivity correction with pH 4 and pH 10 buffers, temperature compensation, and proper storage to prevent degradation.
4Adaptability or versatility
If solution property sensor with multiple sensing patterns is used, then measurement versatility is improved, but manufacturing cost increases
Solution Approach 1:
Instead of integrating multiple sensing patterns on a single complex substrate, the patent segments the measurement functions into separate, simple test paper strips. Each strip is dedicated to measuring one specific property (pH, temperature, or electrical conductivity), making each strip simple to manufacture. Users can select and use only the strip type needed for their specific measurement requirement, avoiding the need to manufacture and stock complex multi-functional sensors.
5Adaptability or versatility
If solution property sensor with multiple sensing patterns is used, then measurement versatility is improved, but device complexity increases
Solution Approach 1:
The patent divides the multi-functional measurement capability into separate, simple test paper strips, each designed for a specific measurement type. This segmentation keeps each individual strip structurally simple and easy to manufacture, while providing users with the versatility to measure multiple solution properties by selecting the appropriate strip type for each measurement need.
6Adaptability or versatility
If solution property sensor with multiple sensing patterns is used, then measurement versatility is improved, but package stability deteriorates
Solution Approach 1:
By segmenting the measurement functions into separate test paper strips, each strip can be packaged independently in a simple, stable format. This avoids the complex packaging requirements needed to protect integrated multi-functional sensors from moisture, contamination, and physical damage. Each strip can be stored in its own sealed container until use, maintaining stability and reliability.
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
Facilitates accurate, real-time analysis of solution properties with reduced manufacturing complexity and improved stability, enabling easier mass production and electrical connectivity.
Implementation Method 1
The film wall has a highly selectivity for hydrogen ions. By measuring a potential change, the pH value of the tested solution is obtained.
Implementation Method 2
In the temperature section, a glass thermometer or an infrared thermometer is mostly used.
Implementation Method 3
the electrical conductivity can be measured using a glass electrode, and an electrical conductivity value is mainly measured by measuring resistance of the aqueous solution.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A solution property sensor (10) is provided and has: a substrate (11), a temperature sensing element (12), an electrical conductivity sensing element (13), a pH value sensing element (14), and a reference electrode (15). The solution property sensor (10) utilizes different sensing elements to sense various solution properties, and all of these sensing elements can be electrically connected and fixed to conductive patterns (115) on the same substrate, thereby facilitating mass production in the industry or reducing production difficulty.