Capacitive Foam Detection in Bioreactors Without Sensor Contact

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Solution Overview

Problem

Current methods for detecting foam in bioreactor systems are inefficient and invasive, particularly for fast-growing foams, leading to potential damage to cells, proteins, and increased production costs due to foam-related issues like filter clogging and pressure increases.

Innovation Solution

A capacitive sensor system with multiple units placed at various positions within the bioreactor system, including disposable containers and ports, to non-invasively detect foam levels and presence using capacitive measurements, transmitting data to a control unit for monitoring and regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conductivity sensors are used to detect foam, then foam detection is possible, but the sensor must come into direct contact with the foam and cultivation liquid

Engineering Contradiction:
Improvefoam detection capabilityVSAvoidsensor contact with foam and liquid
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary substance (liquid with different dielectric properties than the cultivation medium) between the capacitive sensor and the foam/cultivation liquid interface. This intermediary layer allows the sensor to detect foam formation through changes in capacitance without requiring direct contact with the foam or cultivation liquid, thereby maintaining reliable detection while eliminating the harmful contact effect

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the conductivity-based detection mechanism (which requires direct sensor contact) with a capacitive sensing mechanism. This substitution allows foam detection through electrical field interactions and dielectric property changes without mechanical or direct electrical contact between the sensor and the foam/liquid interface

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If optical foam sensors are used, then foam presence can be detected, but the sensor requires a foam contact surface for application

Engineering Contradiction:
Improvefoam detection capabilityVSAvoidsensor structure with contact surface
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the optical detection system (which requires a physical contact surface for light interaction) with a capacitive sensing system. This substitution eliminates the need for complex optical components and contact surfaces, using instead electrical field interactions to detect foam formation, thereby simplifying the device structure while maintaining detection reliability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses an intermediary liquid layer with distinct dielectric properties as a medium between the capacitive sensor and the foam. This intermediary allows the sensor to detect foam through capacitance changes without requiring a dedicated foam contact surface, thereby reducing device complexity while preserving detection capability

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If multiple sensor units are placed at various positions, then foam detection coverage is improved, but system complexity increases

Engineering Contradiction:
Improvefoam detection coverageVSAvoidnumber of sensor units
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the bioreactor system into multiple monitoring zones, each equipped with a capacitive sensor unit. This segmentation allows localized foam detection at critical positions (liquid surface, ports, hoses) without requiring a single complex sensor system, thereby improving overall detection coverage while keeping individual sensor units simple and modular

Inventive Principle:
Principle #1Segmentation

4Loss of time

If foam is detected early, then intervention can be timed to prevent damage, but detection must be non-invasive

Engineering Contradiction:
Improveresponse time for foam interventionVSAvoidinvasiveness of detection method
Core Design Contradiction:
Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The patent replaces invasive mechanical or conductivity-based sensors with non-invasive capacitive sensing. This substitution enables early foam detection through electrical field interactions that do not require physical contact or disruption of the foam structure, thereby achieving timely intervention while maintaining a non-invasive detection approach

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary liquid layer that allows capacitive sensors to detect foam formation early in the process without direct contact. This intermediary medium enables non-invasive detection while maintaining sensitivity to foam growth, allowing timely intervention before foam causes damage to cells or blocks filters

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables reliable and efficient detection of foam growth, allowing for localized intervention to prevent foam-related issues, reducing the risk of cell damage and production downtime by enabling timely anti-foam agent application and system adjustments.

Implementation Method 1

capacitive sensor units that each have at least one electrode system for a capacitive measurement, in particular for a permittivity measurement

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

the capacitive sensor units each have at least one electrode system for a capacitive measurement, in particular for a permittivity measurement

Methodology Applied
Scientific EffectDielectric Permittivity: Dielectric Permittivity

Data Source

PatentEP3872162B1Detection of foam in a bioreactor system
Publication Date: 2024.11.06 SARTORIUS STEDIM BIOTECH GMBH
  • EP3872162B1 patent drawingFigure 1a~1b
  • EP3872162B1 patent drawingFigure 2a~2b
  • EP3872162B1 patent drawingFigure 3

AI summary

System (100) for detecting at least the presence of foam (92, 93) of a medium (9) in a bioreactor system (50), wherein the system (100) comprises: - a bioreactor system (50) with at least one disposable container (1) for receiving the medium (9), which may contain the foam (92, 93); and - at least two capacitive sensor units (10A, 10B) attached to at least two different arrangement positions (A1-A3; B1-B6) of the bioreactor system (50), wherein the capacitive sensor units (10A, 10B) each have at least one electrode system (19) for capacitive measurement and are able to detect the presence of foam (92, 93) at the at least two arrangement positions (A1-A3; B1-B6) based on the capacitive measurement;and wherein the capacitive sensor units (10A, 10B) are designed to transmit detected data concerning the presence of foam (92, 93) to at least one control unit (14) for controlling, controlling and/or regulating foam formation (9) in the bioreactor plant (50) on the basis thereof.