Radial Oxygenator Heat Exchanger Design
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Solution Overview
Problem
Current cardiopulmonary bypass circuits face challenges in minimizing the prime volume of blood, ensuring efficient oxygenation and temperature control, and reducing shear forces on blood cells, which can lead to clotting and trauma.
Innovation Solution
A cardiopulmonary bypass apparatus with a radial flow design where blood moves sequentially through a heat exchanger and an oxygenator, with separate supply of heat transfer and oxygen-containing gas media, arranged concentrically around a core, optimizing blood distribution and minimizing pressure drop and clot formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the oxygenator volume is reduced to minimize prime volume, then the prime volume of blood is reduced, but the blood/membrane interface area is insufficient for adequate oxygen transfer
Solution Approach 1:
The heat exchanger is nested within the oxygenator structure, with heat exchange channels positioned inside the hollow fibers or between the fiber bundles. This nested arrangement allows the heat exchanger to occupy the internal void space of the oxygenator, reducing the overall device volume and prime blood requirement while preserving the external blood/membrane interface area for oxygen transfer
Solution Approach 2:
The patent transitions from a traditional linear or parallel arrangement of heat exchanger and oxygenator to a three-dimensional integrated structure where blood flows radially or concentrically through nested channels. This dimensional reorganization maximizes surface area utilization within a compact volume, maintaining adequate oxygen transfer area while minimizing prime blood volume
2Productivity
If blood flow velocity is increased to improve oxygenation efficiency, then oxygen transfer rate is improved, but shear forces on blood cells increase causing trauma and clotting
Solution Approach 1:
The patent employs curved or concentric flow paths instead of straight linear channels, where blood flows in circular or radial patterns around the nested heat exchanger. This curved geometry distributes shear forces more uniformly across blood cells, preventing localized high-shear trauma while maintaining adequate flow velocity for oxygenation efficiency
Solution Approach 2:
The patent optimizes the geometric parameters of the flow channels, including radius, cross-sectional area, and length, to achieve an optimal balance between flow velocity and shear stress. By adjusting these parameters, the system maintains sufficient velocity for effective oxygen transfer while keeping shear forces below thresholds that cause blood cell trauma
3Device complexity
If the heat exchanger and oxygenator are integrated in a compact design, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The integrated device is segmented into modular components including the oxygenator housing, nested heat exchanger modules, and standardized connection interfaces. This segmentation allows each component to be manufactured and tested separately with controlled precision requirements, then assembled through standardized procedures that maintain overall concentric alignment without requiring ultra-precise single-step manufacturing
Solution Approach 2:
The patent introduces intermediary elements such as alignment rings,定位 features, and flexible sealing structures that facilitate precise concentric arrangement during assembly. These intermediary components act as mediators that compensate for minor manufacturing tolerances and guide the nested components into proper alignment, reducing the stringency of base manufacturing precision requirements
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 radial flow design enhances oxygenation efficiency, reduces prime volume, decreases the risk of clotting, and minimizes shear forces on blood cells, ensuring maximum oxygenated blood delivery to the patient during surgery.
Implementation Method 1
The heat exchanger is generally made of a metal or a plastic, which is able to transfer heat effectively to blood coming into contact with the metal or plastic
Implementation Method 2
Due to the relatively high concentration of carbon dioxide in the blood arriving from the patient, carbon dioxide from the blood diffuses through the microscopic pores in the fibers and into the gas mixture. Due to the relatively low concentration of oxygen in the blood arriving from the patient, oxygen from the gas mixture in the fibers diffuses through the microscopic pores and into the blood
Data Source
AI summary
Disclosed is an apparatus for oxygenating and controlling the temperature of blood in an extracorporeal circuit. The apparatus has an inlet and an outlet that is located radially outward from the inlet in order to define a flowpath through the apparatus. The apparatus comprises: a core that is substantially centrally located in the apparatus and to which blood from a patient can be supplied through the inlet; a heat exchanger comprising a plurality of heat transfer elements that are arranged around the core and between which blood from the core can move radially outward; and an oxygenator comprising a plurality of gas exchange elements that are arranged around the heat exchanger and between which blood from the heat exchanger can move radially outward before exiting the apparatus through the outlet.