Continuous-Flow Centrifuge Chamber Priming via Variable Speed
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Solution Overview
Problem
Conventional priming methods for continuous-flow centrifuges, such as solution priming, require excessive fluid volume and time, and blood priming risks damaging red blood cells and is wasteful, while also extending the connection time for donors or patients.
Innovation Solution
A fluid processing device with a controller, pump system, optical detection assembly, and pressure sensor that rotates the centrifuge chamber at varying rates to convey blood as the priming fluid, ensuring air evacuation without significant volume or steps, and ending the priming when specific flow and pressure conditions are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solution priming is used to evacuate air from the centrifuge chamber, then air evacuation is achieved, but excessive fluid volume and time are required
Solution Approach 1:
The patent changes the physical parameters of the priming fluid by adjusting centrifugal force through variable rotational speeds. The system transitions from low-speed rotation to high-speed rotation to facilitate air evacuation, allowing efficient air removal with minimal fluid volume. This parameter change enables the centrifuge to operate effectively as an air evacuation device rather than requiring large volumes of priming fluid.
Solution Approach 2:
The patent employs periodic variation of rotational speed during the priming process. The centrifuge rotates at different speeds at different stages: initially at lower speeds to allow fluid entry, then increasing to high speeds to evacuate air. This periodic action pattern optimizes both air evacuation efficiency and fluid volume usage, resolving the contradiction between reliable air removal and minimal fluid consumption.
2Ease of manufacture
If blood is used as priming fluid to evacuate air, then no additional non-biological fluid is required, but red blood cells may be damaged and significant blood volume is wasted
Solution Approach 1:
The patent uses parameter changes in centrifugal force to differentiate between blood priming and air evacuation modes. By controlling rotational speed, the system can evacuate air without subjecting blood to damaging centrifugal forces. The high-speed rotation phase is specifically used for air evacuation, while blood processing occurs at controlled speeds that prevent cell damage, thus resolving the contradiction between blood availability and blood cell integrity.
3Reliability
If conventional priming methods are used, then air evacuation is completed, but extended connection time for donors or patients occurs
Solution Approach 1:
The patent implements periodic variation of rotational speed to accelerate the air evacuation process. By alternating between low-speed fluid entry phase and high-speed air evacuation phase, the system completes priming significantly faster than conventional continuous low-speed methods. This periodic action reduces the time donors or patients remain connected while ensuring thorough air evacuation, resolving the contradiction between reliable priming and minimal time loss.
Solution Approach 2:
The patent maintains continuous useful action during the priming process by keeping the centrifuge operating throughout. Rather than stopping between steps, the system continuously rotates at optimized speeds to simultaneously facilitate fluid entry and air evacuation. This continuous operation eliminates idle time and accelerates the overall priming process, reducing connection time while ensuring complete air evacuation.
4Productivity
If high centrifugal force is applied during priming to evacuate air, then air evacuation efficiency increases, but red blood cells may be damaged
Solution Approach 1:
The patent uses periodic action by alternating between low-speed and high-speed rotation phases. During low-speed phases, blood enters the centrifuge chamber without damage. During high-speed phases, air is efficiently evacuated. This temporal separation of functions allows the system to achieve high air evacuation efficiency while protecting blood cells from damaging forces, resolving the contradiction between productivity and harm prevention.
Solution Approach 2:
The patent segments the priming process into distinct functional phases: a low-speed blood entry phase and a high-speed air evacuation phase. By dividing the process into separate temporal segments with different rotational speeds, the system can optimize each phase for its specific function without compromising the other. This segmentation allows high air evacuation efficiency while preventing blood cell damage through appropriate speed control in each segment.
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 reduces the blood volume required for priming, minimizes the risk of blood cell damage, and shortens the time needed for priming, thereby improving efficiency and reducing waste.
Implementation Method 1
As the whole blood is spun by the centrifuge, the heavier (greater specific gravity) components, 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
The pump system is configured to convey fluid through the fluid flow circuit
Data Source
AI summary
A fluid processing device includes a controller, a centrifuge configured to receive and rotate a continuous-flow centrifuge chamber, a pump system, an optical detection assembly, and a pressure sensor. The controller executes a priming procedure in which a priming fluid is conveyed into the centrifuge chamber while the chamber is being rotated by the centrifuge, which moves air out of the chamber via a low-g outlet conduit. Upon detecting priming fluid exiting the centrifuge chamber via the low-g outlet conduit, the chamber is rotated at a higher rate to attempt to move any remaining air out of the chamber via the low-g outlet conduit. The controller then determines, based on signals from the optical detection assembly and pressure sensor, whether there is any air remaining in the centrifuge chamber. If so, the rotational rate is alternately decreased and increased until all the air has been cleared from the centrifuge chamber.