Filter Holding Device for Bioreactor Bag Crossflow Filtration
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Solution Overview
Problem
Traditional stainless steel bioreactors are labor-intensive and costly to clean and sterilize, and perfusion filters in disposable bioreactors face issues with fragility, clogging, and fouling due to rocking motion and attachment to the bag bottom.
Innovation Solution
A filter holding device is designed to attach to the inner surface of flexible bioreactor bags, maintaining the filter at a distance from the bag surface to create a crossflow filtration effect, reducing clogging and fouling by using angled flow deflector areas and stand-offs for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the perfusion filter is attached to the bottom of the bioreactor bag, then the filter is securely positioned, but the filter gets clogged and fouled easily
Solution Approach 1:
The filter is moved from a bottom attachment position to a vertical sidewall attachment position. This dimensional change in placement allows the filter to be positioned away from the bag bottom while maintaining secure attachment through the filter holder device with attaching means.
Solution Approach 2:
A filter holder device is introduced as an intermediary component between the filter and the bioreactor bag sidewall. This holder provides secure positioning through attaching means while maintaining the filter at an optimal distance from the bag surface, preventing direct contact that causes clogging and fouling.
2Reliability
If the filter is provided close to the inner surface of the flexible bag, then the filter is securely positioned, but the filter membranes get damaged by the screen when forced into the bioreactor walls by rocking motion
Solution Approach 1:
The filter holder device serves as a protective intermediary between the fragile filter membrane and the rigid screen/bag wall interface. It absorbs and distributes mechanical stresses from rocking motion, preventing direct force transmission that would damage the filter membrane.
Solution Approach 2:
The filter holder device is designed with structural features that cushion and absorb mechanical impacts before they reach the filter membrane. This pre-protection mechanism prevents damage from rocking-induced forces against the bioreactor walls.
3Ease of manufacture
If the filter is attached to the bottom of the bioreactor bag, then the filter is easy to install, but the filter probably will get clogged and fouled easily
Solution Approach 1:
The filter installation is moved from the bottom surface to the vertical sidewall of the bioreactor bag. This positional change in another dimension maintains installation simplicity through the filter holder device while eliminating the clogging and fouling problems associated with bottom attachment.
4Device complexity
If the filter is provided inside the bioreactor without a holder device, then the device complexity is reduced, but the filter cannot be maintained at a distance from the bag surface to prevent clogging
Solution Approach 1:
The filter holder device is designed as a multi-functional component that simultaneously provides attachment to the bag sidewall, maintains optimal distance from the bag surface, and prevents clogging. This consolidates multiple functions into one device, minimizing overall system 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 crossflow filtration design extends filter lifespan by minimizing clogging and fouling, allowing for efficient fluid flow and easier maintenance, while maintaining a sterile environment.
Implementation Method 1
maintaining the filter at a distance from the bag surface to create a crossflow filtration effect
Data Source
AI summary
A filter holding device (1; 41; 75; 81) arranged for providing at least one filter (7; 43a, 43b; 85) inside a flexible bag (3; 71), said filter holding device comprising attaching means (19a-d, 21a-d; 79; 83) for attaching the filter holding device to an inner surface of the flexible bag such that the at least one filter held by the filter holding device is provided at a distance from the inner surface of the flexible bag.