Flexible Pouch Mixing System for Biopharmaceutical Fluids
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Solution Overview
Problem
Existing container systems for mixing biopharmaceutical compositions in large-scale operations face inefficiencies in mixing due to the use of flexible bags supported by stainless-steel vessels, which require complex driving solutions and do not effectively create a vortex for rapid mixing.
Innovation Solution
The system comprises a flexible plastic bag with a bottom, top, and tubular sidewall, arranged within a tank with a rectangular base and four upwardly extending panels. The bag is unfolded to create a parallelepiped configuration, allowing the stirring device to be driven from below, which efficiently creates a vortex at the liquid's surface despite significant height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a flexible bag is used inside a rigid container with a stirring device driven from below, then the bag can be easily stored in a folded state and offers significant capacity, but mixing efficiency becomes insufficient at large scales
Solution Approach 1:
The patent applies curvature by rounding the four corners of the bag's base to create a curved surface configuration. This curvature allows the bag to maintain contact with the rigid container walls while enabling effective vortex formation during mixing, resolving the contradiction between maintaining bag capacity and improving mixing efficiency at large scales
2Stability of the object's composition
If the bag corners contact the rigid container walls, then the bag is stable in position, but vortex formation is inhibited and mixing efficiency decreases
Solution Approach 1:
The rounded corner design creates a curved transition zone between the bag and container walls. This curvature prevents sharp corner contact while maintaining overall positional stability, allowing vortex formation without compromising bag stability during the mixing process
3Device complexity
If the stirring device is driven from below, then the system structure is simplified, but creating a vortex at the liquid surface becomes difficult with significant height
Solution Approach 1:
The curved corner configuration of the bag works synergistically with the bottom-driven stirring device to enhance vortex formation. The curvature creates favorable flow patterns that amplify the vortex-generating capability of the impeller, enabling effective mixing even with significant liquid heights while maintaining the simple bottom-driven configuration
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 configuration enables efficient mixing of large volumes (over 2000 L) within two minutes or less, preventing undesirable folds and maintaining a rectangular cross-section, thus enhancing mixing efficiency and preventing product loss during drainage.
Implementation Method 1
efficiently creates a vortex at the liquid's surface
Implementation Method 2
efficient mixing of large volumes (over 2000 L) within two minutes or less
Data Source
AI summary
Initially heterogenous biopharmaceutical composition is mixed in a bag designed as a mixed bioreactor with capacity of at least 1500 liters, using an apparatus that includes a tank, the flexible and collapsible bag received in the tank and a stirring device. The device includes an impeller driven from below for initiating agitation adjacent to a tank base. Once the bag is stretched under liquid pressure, it becomes parallelepiped with a bottom wall, a top wall and a sidewall. The bag, in contact against four side panels of the tank, has a rectangular cross section including four rounded corners each spaced from the side wall.