Micro Total Analysis System Fluid Mixing Ratio Control
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Solution Overview
Problem
In micro total analysis systems, achieving a stable and accurate mixing ratio of two fluids with significantly different ratios is challenging due to variations in flow path resistances and pumping forces, especially when the mixing ratio deviates from 1:1, leading to instability in flow rates and mixing accuracy.
Innovation Solution
The system employs a micro total analysis system with multiple micro-pumps of the same shape, where the drive voltages are kept equal, and flow path resistances are adjusted by varying the sectional area or length of the flow paths to maintain a consistent mixing ratio of m:n, ensuring stable fluid mixing without altering drive voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the drive voltage of one micro-pump is lowered considerably to achieve a high mixing ratio (deviating from 1:1), then the mixing ratio can be adjusted, but the mixing ratio becomes unstable due to the pumping force of the other pump
Solution Approach 1:
The invention changes the physical parameters of the flow paths (sectional area or length) to adjust flow path resistances, allowing mixing ratio control without varying drive voltages. This resolves the contradiction by providing adaptability through parameter changes while maintaining stability through constant voltage operation.
Solution Approach 2:
The invention replaces the mechanical control method (adjusting drive voltages) with a resistance-based control method (modifying flow path geometry). This substitution eliminates the instability caused by voltage adjustments while maintaining the ability to control mixing ratios.
2Ease of operation
If the flow paths are slowly filled with fed fluids over time, then the system starts feeding fluids from an initial empty state, but the flow path resistances increase with time causing flow rates to decrease
Solution Approach 1:
The invention designs the flow paths with pre-calculated resistance values that account for the filling process. By preliminarily setting the resistance characteristics, the system compensates for the gradual resistance increase during filling, maintaining reliable and consistent flow rates throughout the operation.
3Adaptability or versatility
If the flow path is extended downward from the joining part to accommodate high mixing ratios, then the system can handle varying flow rates, but the flow rates vary with time due to changes in downstream flow path resistance and liquid feeding pressure
Solution Approach 1:
The invention modifies the flow path resistance parameters (sectional area or length) to achieve the desired mixing ratios. By carefully designing these parameters, the system provides adaptability for different mixing requirements while maintaining flow rate stability through optimized resistance characteristics that compensate for downstream variations.
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 allows for precise and stable mixing of fluids at various ratios, enhancing the accuracy and reliability of fluid mixing in micro total analysis systems, even when the mixing ratio is far from 1:1, thereby improving analytical precision and efficiency.
Implementation Method 1
a piezoelectric element 44 and a vibration plate 43 which are laminated on the side of the pressure chamber 45 facing the inside of the pressure chamber 45
Implementation Method 2
a vibration plate 43 which are laminated on the side of the pressure chamber 45 facing the inside of the pressure chamber 45
Implementation Method 3
the flow path resistances which are a load of the micro-pumps are slowly increased with time
Data Source
AI summary
A system including an inspection chip equipped with at least a pump connection having a flow path opening for interconnecting to a micro-pump, a flow path through which a fluid flows, and a fluid mixing section for joining and mixing two or more fluids, and including a system body equipped with at least a base body, a chip connection having a flow path opening for interconnecting to the inspection chip, a micro-pump unit in the base body including micro-pumps in substantially the same shape, a detection processor and a controller for controlling at least the functions of the micro-pump unit and the detection processor, and the joining amount ratio is adjusted to set the mixing ratio of two fluids to be joined in the fluid mixing section to be approximately m:n (not 1:1) by making the drive voltages of the micro-pumps substantially equal to each other.