Dual Feedback Vacuum Fluidics for Flow Cytometry
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Solution Overview
Problem
Flow cytometer systems with pressure-driven fluidics are complex due to the need for high-pressure components, while vacuum-driven systems simplify design but require precise control of fluid ratios and flow rates to maintain analysis accuracy.
Innovation Solution
A vacuum-driven fluidics system for flow-type particle analyzers that combines sample and sheath fluids just before analysis, using a variable-resistance fluidic resistor to modulate the relative proportions of fluids and maintain constant flow rates through a flow cell, with feedback control to regulate vacuum levels and ensure accurate fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure-driven fluidics is used, then fluid flow control is achieved, but system complexity increases due to high-pressure components
Solution Approach 1:
The patent inverts the conventional pressure-driven approach by using vacuum-driven fluidics. Instead of pressurizing fluids to control flow, the system applies vacuum pressure to draw fluids through the flow cell, eliminating the need for high-pressure components, pumps, and complex sealing systems while maintaining reliable flow control.
Solution Approach 2:
The patent replaces mechanical pressure-generating components (pumps, pressure regulators) with a vacuum-based system. This substitution eliminates complex mechanical systems while achieving the same fluid transport function through atmospheric pressure differential and vacuum suction.
2Device complexity
If vacuum-driven fluidics is used, then system design is simplified, but precise control of fluid ratios and flow rates becomes challenging
Solution Approach 1:
The patent incorporates feedback control systems that monitor fluid flow rates and vacuum levels, automatically adjusting parameters to maintain precise fluid ratios. Sensors detect flow conditions and feed this information back to control mechanisms, ensuring accurate sample-to-sheath fluid ratios despite variations in vacuum pressure or flow conditions.
Solution Approach 2:
The patent utilizes variable-resistance fluidic resistors that can dynamically adjust their resistance parameters to control flow distribution. By changing the resistance parameter of fluidic pathways, the system precisely controls the ratio of sample fluid to sheath fluid without requiring complex mechanical adjustment mechanisms.
3Measurement precision
If sample and sheath fluids are combined early, then system complexity increases, but analysis accuracy improves
Solution Approach 1:
The patent segments the fluidic system into distinct sample fluid pathway and sheath fluid pathway that remain separate until the point of analysis. This segmentation allows independent control and optimization of each fluid stream while maintaining simple system architecture, combining the benefits of early mixing for analysis accuracy with late combination for system simplicity.
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 system simplifies the design of flow cytometers by eliminating pressurized components and allows for precise control of fluid ratios and flow rates, maintaining analysis accuracy and efficiency while reducing system complexity.
Implementation Method 1
a vacuum pump having a controllable power level, in vacuum communication with said outlet line, configured to draw a vacuum in said outlet line, thereby pulling said sample and sheath fluids through said flow cell
Implementation Method 2
wherein said sample fluid line or said sheath fluid line comprises a variable-resistance fluidic resistor
Implementation Method 3
a first control feedback circuit configured to regulate the power of said vacuum pump in response to the pressure drop measured by said first sensor
Data Source
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AI summary
The present invention relates to a vacuum-driven fluidic system for a flow-type particle analyzer. The system includes a vacuum pump which creates a pressure drop downstream of the flow cell, which pulls sheath fluid and sample fluid through the flow cell. A variable-resistance fluidic resistor is configured to control the ratio of sample fluid flow to sheath fluid flow. Dual feedback circuits, one configured to modulate the vacuum pump power in response to the pressure drop across the flow cell, referred to as the dynamic pressure drop, and a second configured to modulate the vacuum pump power in response to the pressure drop created by the vacuum pump relative to ambient pressure, referred to as the static pressure drop, are used to automatically control the system. The present invention enables adjustment of the sample fluid flow rate while maintaining a constant total fluid flow through the flow cell, and further, enables pausing the system without significant fluctuations in the vacuum.