Moisture Tester Using Multi-Electrode Paste Impedance
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Solution Overview
Problem
Current methods for determining moisture content in foods, such as those using electric current or infrared spectroscopy, are often inaccurate and prone to human error due to inconsistencies in sample preparation and physical properties of foodstuffs like fruits and vegetables with thick skins or seeds, leading to variations in test results.
Innovation Solution
A process and apparatus utilizing multiple impedance measurements at different locations within a homogenized paste of the material, combined with temperature measurements, to determine moisture levels, minimizing operator handling and introducing automated preparation to ensure consistency and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual sample preparation and measurement methods are used, then the procedure is simple and quick, but measurement precision deteriorates due to human error and inconsistency
Solution Approach 1:
The patent replaces manual mechanical operations (chopping, grinding, packing) with an automated sample preparation system that homogenizes food materials into paste form. This substitution eliminates operator variability in sample preparation, directly improving measurement precision while accepting increased device complexity through automation.
Solution Approach 2:
The patent changes the physical state of the sample from solid food material to homogenized paste, and uses multiple impedance measurements at different frequencies and locations. This parameter transformation allows for more consistent and accurate moisture determination by eliminating the variability inherent in manual sampling and preparation.
2Measurement precision
If multiple impedance measurements at different locations are taken, then measurement precision improves, but the time required for testing increases
Solution Approach 1:
The patent performs preliminary homogenization of the food material into paste form before taking measurements. This preliminary action ensures that the sample is in a uniform state, allowing multiple impedance measurements to be taken more efficiently and consistently, reducing the overall time required while maintaining high precision.
Solution Approach 2:
The patent employs continuous impedance measurements across multiple locations and frequencies without interruption once the paste is prepared. This continuous measurement approach maximizes the use of available data and minimizes idle time, improving precision through multiple measurements while controlling for time loss.
3Reliability
If automated sample preparation is used, then measurement precision improves by eliminating operator error, but device complexity increases
Solution Approach 1:
The patent replaces manual chopping, grinding, and packing operations with an automated sample preparation system. This substitution eliminates operator error and ensures consistent sample homogenization, directly improving reliability. The increased device complexity is justified by the elimination of human variability and the standardization of the preparation process.
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
This approach reduces human error and variability, providing more accurate and consistent moisture content determinations by using calibrated standards and statistical processing of impedance and temperature data to correlate with known moisture levels, thereby improving the reliability of moisture level assessments in foodstuffs.
Implementation Method 1
The impedance is determined by applying an alternating electrical potential at a selected frequency, thereby enabling the measurement to be compared with calibrated standards
Implementation Method 2
Temperature measurements of the material are also taken. The impedance reflects both the electrical resistivity and dielectric constant of the material, both of which vary with the moisture content and the temperature
Data Source
AI summary
The moisture content of a foodstuff or other solid matter is determined by reducing the matter to a paste, packing the paste into a vessel equipped with multiple pairs of plate electrodes and one or more temperature sensors, applying an AC voltage across each pair of electrodes, and measuring the impedance of the paste from each pair of electrodes. The multiple impedance measurements are averaged or otherwise processed to obtain a value that is representative of the paste, and that value and the temperature are processed against calibration data to achieve a value of the moisture content of the paste.