Bioprocessing Impeller Vent Holes for Bubble Dispersion
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Solution Overview
Problem
Existing bioprocessing systems face issues with sparge gas bubbles becoming trapped in impeller assemblies, leading to localized nonhomogeneous zones and cell damage due to bubble popping.
Innovation Solution
The impeller assembly features a hub with blades and vent holes that allow sparge gas to pass through, minimizing bubble trapping and enhancing gas dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sparge gas is introduced into the bioreactor to improve mixing and oxygenation, then gas transfer efficiency is improved, but gas bubbles become trapped in the impeller assembly creating localized nonhomogeneous zones
Solution Approach 1:
The impeller assembly is segmented into multiple components including a top impeller, bottom impeller, and intermediate impeller arranged at different vertical positions. This segmentation allows gas bubbles to pass through multiple levels rather than becoming trapped in a single location, improving overall gas dispersion while maintaining mixing efficiency.
Solution Approach 2:
The patent introduces a vertical dimension to gas bubble transport by positioning impellers at different heights (top, intermediate, bottom). Gas bubbles travel vertically through the impeller assembly from bottom to top, utilizing the vertical dimension to prevent trapping and enhance dispersion throughout the bioreactor volume.
2Productivity
If sparge gas bubbles are trapped in the impeller assembly, then localized gas zones are created, but this leads to bubble popping that damages cells
Solution Approach 1:
The harmful function of gas bubble trapping is extracted and eliminated by designing vent holes and open pathways in the impeller assembly structure. This allows gas bubbles to be taken out of the impeller assembly and dispersed into the bulk fluid, removing the source of cell damage while preserving the beneficial mixing function.
Solution Approach 2:
The patent converts the potentially harmful trapped gas bubbles into beneficial dispersed gas bubbles by providing controlled pathways through the impeller assembly. The gas that would otherwise be trapped and cause damage is instead guided through the impeller structure to create gentle, distributed gas-liquid mixing that enhances oxygenation without cell damage.
3Device complexity
If traditional impeller design is used to maintain simple structure, then device complexity is low, but gas bubbles become entrapped creating nonhomogeneous zones
Solution Approach 1:
The impeller assembly is designed with multi-functionality, where the same structural components (impeller blades, hub, and vent holes) simultaneously perform mixing functions and gas dispersion functions. The vent holes serve dual purposes: preventing bubble trapping while maintaining structural integrity, thereby achieving fluid homogeneity without significantly increasing device complexity.
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 solution improves gas dispersion and reduces cell damage, increasing the efficiency and homogeneity of bioprocessing by preventing bubble accumulation and vibration.
Implementation Method 1
at least one vent hole in the impeller assembly providing a pathway for gas to travel from an area beneath the impeller assembly to an area above the impeller assembly
Implementation Method 2
a sparger outputs small gas bubbles into a liquid in order to agitate and/or dissolve the gas into the liquid
Implementation Method 3
An agitator assembly disposed within the bag is used to mix the fluid
Data Source
AI summary
An impeller assembly for a bioprocessing system includes a hub, a plurality of blades disposed along a circumferential direction of the hub and spaced apart from each other, and at least one vent hole in the impeller assembly providing a pathway for gas to travel from an area beneath the impeller assembly to an area above the impeller assembly.