Bioreactor Filter Pocket Structure for Large-Volume Stability

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Solution Overview

Problem

Existing bioreactors face challenges in maintaining the integrity of filter bags for large volumes, particularly 100 to 200 liters, due to detachment of filter edges under hydrostatic pressure and mechanical stress, and difficulties in joining materials with different melting points.

Innovation Solution

A bioreactor design with a filter pocket stabilized by direct connections between the filter medium and the bioreactor wall, using through-openings in a spacer to secure the filter medium without welding or gluing, ensuring the spacer is not involved in these connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If edge welding of filter medium is used to attach filter pocket to bioreactor wall, then filter pocket is secured to wall, but for large volumes (100 liters or more) the filter medium edge detaches due to hydrostatic pressure and mechanical stress

Engineering Contradiction:
Improvefilter pocket integrityVSAvoidattachment strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The filter pocket attachment is divided into multiple discrete welding points distributed across the filter medium surface rather than relying on a single continuous edge weld. This segmentation distributes the mechanical stress and hydrostatic pressure loads across multiple independent attachment points, preventing the filter medium from detaching in large-volume bioreactors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The attachment method transitions from a two-dimensional edge weld (along the perimeter) to a three-dimensional distributed pattern of welding points across the surface of the filter medium. This dimensional change allows the filter pocket to withstand higher pressures and mechanical stresses by utilizing multiple attachment points throughout the structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If multiple materials (filter medium, spacer, bioreactor wall) are joined together by welding, then components are connected, but the significantly different melting points of materials make welding problematic or impossible

Engineering Contradiction:
Improvejoining feasibilityVSAvoidmaterial compatibility
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The spacer is extracted from the welding process entirely. Instead of attempting to weld all three materials (filter medium, spacer, and bioreactor wall) together, the spacer is positioned and secured separately, allowing the filter medium to be welded directly to the bioreactor wall without the spacer interfering. This eliminates the material compatibility problem caused by different melting points.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The design creates a situation where the filter medium acts as an intermediary between the bioreactor wall and the spacer. The filter medium is welded to the wall, and the spacer is positioned against the filter medium but not welded to it, allowing each material to be joined only to compatible materials.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3908648B1Bioreactor comprising a filter pocket, and method for producing same
Publication Date: 2026.01.28 SARTORIUS STEDIM BIOTECH GMBH
  • EP3908648B1 patent drawingFigure 1~3
  • EP3908648B1 patent drawingFigure 4~6

AI summary

A bioreactor and a method for culturing microorganisms and cells of animal or vegetable origin comprise a filter pocket provided on the inner surface of a flexible wall (18) of the bioreactor, the outer side of said pocket being delimited by the wall (18) of the bioreactor and the inner side being delimited by a filter-pocket wall. At least part of the inner-side filter-pocket wall is formed by a filter medium (12). A spacer (10) is provided between the wall of the bioreactor (18) and the filter medium (12). The spacer (10) has at least one passage opening (20). A connector section (22) of the filter medium (12) protrudes through the passage opening (20) and is directly connected to the wall (18) of the bioreactor.