Bioreactor Impeller Assembly with Flexible Drive Isolation
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Solution Overview
Problem
Conventional bioreactor mixing systems face limitations in scalability and mixing efficiency, particularly when a single impeller is insufficient for larger volumes or higher mixing rates, and require cleaning and sterilization of rigid drive shafts, which complicates reuse and maintenance.
Innovation Solution
A fluid processing system with a flexible container and modular impeller assembly, where a flexible tube isolates the drive shaft from the fluid, allowing for higher mixing rates by mounting multiple impellers on a rigid second tubular connector, and enabling easy sterilization and disposal after use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single impeller is used in a flexible bag system, then the system is simple and easy to manufacture, but the mixing rate is insufficient for larger volumes
Solution Approach 1:
The single impeller is divided into multiple impellers (first impeller and second impeller) mounted on separate sections of the drive shaft. This segmentation allows each impeller to independently contribute to mixing, thereby increasing the overall mixing rate while maintaining the simplicity of the flexible bag system.
Solution Approach 2:
The patent transitions from a single impeller configuration to a multi-impeller configuration along the length of the drive shaft, effectively utilizing the longitudinal dimension of the bag to increase mixing capacity without increasing the radial footprint.
2Strength
If a rigid drive shaft is used, then the structure is strong and can transmit power effectively, but cleaning and sterilization are required between uses
Solution Approach 1:
The drive shaft is extracted from direct contact with the fluid by introducing a flexible tube that encloses it. The drive shaft remains rigid and strong for power transmission, but the flexible tube acts as a barrier that prevents fluid contact, eliminating the need for cleaning and sterilization of the drive shaft between uses.
Solution Approach 2:
The flexible tube serves as an intermediary between the rigid drive shaft and the fluid. It allows the drive shaft to maintain its structural strength and power transmission capability while preventing direct interaction with the fluid, thus eliminating cleaning and sterilization requirements.
3Volume of moving object
If the flexible bag is collapsed or folded for storage, then transportation and storage space are reduced, but the rigid drive shaft limits this ability
Solution Approach 1:
The flexible tube enclosing the drive shaft is made of a flexible material that can be collapsed or folded along with the bag. This flexible shell approach allows the entire assembly to be compacted for storage and transportation while the drive shaft inside remains rigid and functional.
4Productivity
If multiple impellers are mounted on the drive shaft, then the mixing rate increases for larger volumes, but the device complexity increases
Solution Approach 1:
Multiple impellers are merged onto a single drive shaft assembly, with the first and second impellers mounted on the drive shaft at different positions. This merging approach increases mixing capacity while consolidating the drive mechanism into a single integrated unit, managing the complexity through unified design.
Solution Approach 2:
The drive shaft serves multiple functions: it transmits power to multiple impellers, provides structural support for the flexible tube, and acts as a central axis for the entire mixing assembly. This multi-functionality reduces the need for separate components, thereby managing device complexity while achieving high mixing rates.
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 system achieves efficient mixing in larger volumes with scalable and cost-effective operation, eliminating the need for cleaning and sterilization of drive shafts, and facilitating easy storage and transportation by folding the system.
Implementation Method 1
a flexible tube isolates the drive shaft from the fluid, allowing for higher mixing rates by mounting multiple impellers on a rigid second tubular connector
Implementation Method 2
Rotation of the drive shaft and impeller facilitates mixing and/or suspension of the fluid contained within the flexible bag
Implementation Method 3
A first end of the tube is rotatably coupled by a dynamic seal to the bag while an opposing second end of the tube is sealed to an impeller
Data Source
AI summary
A method for operating a bioreactor includes passing a drive shaft into a first tubular connector and a second tubular connector projecting from the first tubular connector, the first tubular connector and the second tubular connector being at least partially disposed within a container, the first tubular connector being more flexible than the second tubular connector, the second tubular connector having a length that comprises at least 20% of a combined length of the first tubular connector and the second tubular connector. Rotating the drive shaft so as to rotate the first tubular connector and the second tubular connector within the container.