Microfluid Flow Meter Using Volumetric Electrode Detection
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Solution Overview
Problem
Current miniature flow meters lack a reliable calibration method and have limitations in measuring low flow rates, with existing methods being either inaccurate or impractical for commercial use due to external environmental restrictions and high error rates.
Innovation Solution
A flow measuring device with multiple electronic circuits and channels, utilizing a volumetric method to detect resistance variation signals from gas-liquid or liquid-liquid interfaces, allowing for precise measurement of microfluid flow rates by calculating the ratio of volume to time difference across multiple pairs of electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal sensing type miniature flow meter is used, then metering capability can be achieved, but maximum error reaches up to 10%
Solution Approach 1:
The patent replaces thermal sensing and pressure gradient methods with a volumetric method using electrode pairs to detect gas-liquid or liquid-liquid interfaces. This substitution eliminates the measurement errors inherent in thermal and pressure-based methods, achieving accurate flow rate measurement without the 10% error margin of thermal sensing devices.
Solution Approach 2:
The patent changes the measurement parameter from thermal or pressure-based indirect measurement to direct volumetric measurement through electrode detection. By detecting the position of fluid interfaces through electrical resistance changes, the system achieves more reliable and accurate flow rate measurement.
2Measurement precision
If gravimetric method is used for flow measurement, then measurement capability is achieved, but the system becomes bulky and requires highly stable external surroundings
Solution Approach 1:
The patent extracts the essential measurement function from the complex gravimetric system by using simple electrode pairs to detect fluid interfaces directly. This extraction eliminates the need for bulky components and stable environmental conditions, achieving accurate measurement in a compact form factor suitable for commercial use.
Solution Approach 2:
The patent substitutes the mechanical and environmental dependencies of gravimetric measurement with an electrical detection system. The electrode-based volumetric method replaces the need for precise mass measurement and stable environmental conditions, simplifying the system while maintaining measurement accuracy.
3Measurement precision
If pressure gradient type miniature flow meter is used, then metering capability is achieved, but minimum metering capability approximates to around 300 μL/min
Solution Approach 1:
The patent implements a dynamic measurement system where electrode pairs can detect fluid interfaces across different flow rates. The system adapts to various flow conditions by adjusting the detection parameters and electrode positioning, enabling accurate measurement from very low flow rates (0.01 μL/min) up to higher flow rates (1.05 mL/min), thus achieving broad flow rate range adaptability.
4Reliability
If conventional calibration method using graduated syringe is used, then calibration can be performed, but errors arise due to subjective presumption
Solution Approach 1:
The patent implements a self-calibrating system where the device uses its own electrode pairs to detect fluid interfaces and calculate flow rates automatically. This self-service calibration eliminates the need for external graduated syringes and subjective readings, achieving reliable and accurate calibration through objective electrical detection.
Solution Approach 2:
The patent replaces the mechanical graduated syringe calibration method with an electrical detection system. The electrode-based volumetric measurement provides objective, repeatable calibration data without the subjective errors inherent in manual reading methods, thereby improving both calibration reliability and accuracy.
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
The device provides accurate and reliable measurement of flow rates from 1.05 mL/min to 0.01 μL/min, overcoming the limitations of existing technologies by minimizing errors and accommodating various flow conditions with improved sensitivity and precision.
Implementation Method 1
detecting a respective variation signal corresponding to the respective at least two sections
Data Source
AI summary
A device for measuring a flow of a fluid is provided. The device includes a base, a channel, and at least two electronic circuits. The channel is mounted on the base, flowing the fluid therein and having at least two sections, and the at least two electronic circuits are electrically connected to the respective at least two sections, detecting a respective variation signal corresponding to the respective at least two sections so as to obtain the flow according to the respective variation signal.