Microfluidic Pipe Flow Measurement With Fouling Detection
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Solution Overview
Problem
Existing microfluidic flow measurement systems are prone to fouling, leading to erroneous measurements and potential sensor malfunction due to changes in hydraulic resistance and thermal dynamics, which are difficult to detect and correct.
Innovation Solution
A flow measurement system with multiple pressure sensors arranged in series, calculating flow rates and proportional differences to detect blockages and fouling, generating alerts, and using a specially configured computer to calculate average flow rates and adjust hydraulic resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flow measurement methods (flow cytometers, particle counters) are used, then flow rate can be measured, but the device complexity is high and manufacturing cost is high
Solution Approach 1:
The patent replaces complex mechanical flow measurement systems (flow cytometers, particle counters) with an optical measurement system. The flow rate is determined by measuring the intensity of light emitted by fluorescently labeled cells passing through a detection zone, eliminating the need for complex mechanical counting mechanisms while maintaining measurement accuracy.
Solution Approach 2:
The patent uses fluorescent labels as optical copies or markers attached to cells. Instead of directly detecting and counting physical cells with complex instrumentation, the system detects the optical signal (fluorescence) emitted by these labels, which serve as simplified proxies for the actual cells, thereby reducing device complexity.
2Measurement precision
If conventional flow measurement methods are used, then flow rate can be measured, but the manufacturing cost is high
Solution Approach 1:
The patent replaces expensive mechanical flow measurement instrumentation with a cost-effective optical detection system. By using simple light sources, fluorescent labels, and photodetectors instead of complex mechanical flow cytometers, the manufacturing cost is significantly reduced while maintaining the ability to measure flow rate accurately.
Solution Approach 2:
The patent employs disposable fluorescently labeled cells or beads as measurement probes. These inexpensive, single-use labeled objects replace expensive, reusable mechanical measurement components, reducing both initial manufacturing cost and long-term operational costs.
3Productivity
If microfluidic pipes with small cross-sections are used, then fluid flow control is improved, but the velocity distribution becomes non-uniform affecting measurement accuracy
Solution Approach 1:
The patent changes the measurement parameter from direct velocity measurement to light intensity measurement. By measuring the intensity of fluorescence emitted by labeled cells passing through a fixed detection zone, the system avoids the need to directly measure and average complex velocity distributions, thereby maintaining measurement accuracy despite non-uniform flow profiles in narrow microchannels.
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 system provides reliable flow measurements by detecting and alerting fouling, ensuring accurate readings and enabling flow control despite partial blockages, with the ability to recalibrate and maintain sensors effectively.
Implementation Method 1
a stream of fluorescently labeled cells to be measured is caused to pass through a detection zone where the cells are illuminated by a light source
Data Source
Figure 1a
Figure 1b~2
Figure 3
AI summary
The present invention relates to a system for measuring the flow rate in a microfluidic pipe, comprising n pressure sensors Ci (C1, C2, ..., Cn) arranged in series on a pipe and measuring the pressure Pi (P1, P2, ..., Pn) of the liquid passing through same, these sensors being separated from one another by pipe portions Ri (R1, R2, ..., Rn-1), each having a hydraulic resistance Rhi (Rh1, Rh2, Rhn-1), thus making it possible to measure the pressure variations or head loss ΔΡi (ΔΡ1, ΔΡ2, ..., ΔΡn-1) between two consecutive sensors of the liquid flowing successively through these hydraulic resistances, the comparison between the estimated flow rates Di = ΔΡi/Ri (D1, D2, ..., Dn-1) making it possible to determine the fouling of the microfluidic pipe.