Color-Based Interface Control in Blood Centrifugal Separation
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Solution Overview
Problem
Existing centrifuge systems for blood separation struggle with maintaining the interface position between fluid components during centrifugation, particularly when dealing with lipemic plasma, as they rely on light transmission through the plasma layer which can be problematic due to reduced optical clarity.
Innovation Solution
The system employs color-based optical measurements using reflectance spectroscopy to determine the dominant wavelength of fluid layers, allowing for continuous control of the interface position by measuring color duration, independent of plasma clarity, and adjusting flow rates to maintain desired fluid thicknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light transmission through the plasma layer is used to determine interface position, then the measurement method is simple, but the measurement precision deteriorates when plasma becomes less optically clear
Solution Approach 1:
The patent applies colorimetric detection by measuring the color of reflected light from the plasma layer using a colorimeter or spectrophotometer. Different plasma conditions (clear vs. lipemic) produce different color signatures that can be distinguished and used to accurately determine interface position regardless of optical clarity. This transforms the measurement from relying on light transmission intensity to relying on color wavelength analysis.
Solution Approach 2:
Instead of measuring light transmission through the plasma layer (traditional method), the patent inverts the approach by measuring the color of reflected light from the plasma layer. This inversion allows measurement of plasma properties without requiring light to pass through the plasma, thereby maintaining measurement precision even when plasma optical clarity is compromised.
2Ease of operation
If the interface position is not accurately controlled, then the system operation is simpler, but the separation efficiency and purity deteriorate
Solution Approach 1:
The patent implements a feedback control system where the colorimeter continuously monitors plasma color and interface position, and the controller automatically adjusts pump flow rates to maintain the interface at the desired position. This closed-loop feedback maintains high separation efficiency and purity while requiring minimal operator intervention, as the system self-corrects for variations in plasma properties.
3Device complexity
If light transmission method is used for interface detection, then the device complexity is low, but the reliability deteriorates when plasma clarity is compromised
Solution Approach 1:
The patent replaces the mechanical/optical transmission-based detection system with a colorimetric reflection-based system. Instead of measuring light transmission through the plasma layer, a colorimeter measures the color of reflected light, which is not affected by plasma optical clarity. This substitution maintains device simplicity while significantly improving detection reliability in various plasma conditions.
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 method effectively controls the interface position in centrifuges, ensuring efficient separation procedures even with lipemic plasma, enhancing separation efficiency and reducing contamination risks.
Implementation Method 1
As the centrifuge assembly rotates the centrifugal separation chamber of the disposable fluid processing assembly during a collection procedure, the heavier (greater specific gravity) components of the whole blood in the separation chamber, such as red blood cells, move radially outwardly away from the center of rotation toward the outer or 'high-G' wall of the separation chamber. The lighter (lower specific gravity) components, such as plasma, migrate toward the inner or 'low-G' wall of the separation chamber.
Implementation Method 2
A color-based interface control system using reflectance spectroscopy measures the dominant wavelength of fluid layers to determine the interface position
Data Source
AI summary
A fluid separation device includes a centrifugal separator configured to receive a centrifugal separation chamber of a disposable fluid flow circuit, a pump system configured to convey a fluid into the centrifugal separation chamber and to remove a separated fluid component from the centrifugal separation chamber via an outlet, a color-based interface monitoring system configured to determine an interface position between separated fluid components continuously flowing through the centrifugal separation chamber based on dominant wavelength measurements of layers of separated fluid components during a centrifugal separation procedure, and a controller configured to measure the dominant wavelengths of the layers, calculate a duration as a color time for each measured dominant wavelength, set target color times, calculate error signals and calculate control signals to adjust the pump system to control the flow rate and interface position.