Bioreactor Mixing Time Detection Using Optical Decolorization

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for determining mixing time in bioreactors are invasive, inaccurate, and prone to human error, lacking consistency and objectivity across different scales.

Innovation Solution

A device arrangement using a light source, photodetector, and processing unit to objectively quantify mixing time by analyzing light intensity changes during a decolorization reaction, eliminating human error and ensuring consistent measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If visual inspection based on video footage analysis is used to determine mixing time, then the method is simple and inexpensive, but the results are subjective and error-prone due to human observation variability

Engineering Contradiction:
Improvesimplicity of methodVSAvoidobjectivity of measurement
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical/visual observation system with an optical detection system. A photodetector measures light intensity changes during the decolorization reaction, substituting human visual inspection with automated optical measurement. This eliminates subjectivity while maintaining the simplicity of the decolorization chemistry method.

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

Solution Approach 2:

The patent introduces light as an intermediary to transfer information about mixing state from the reaction medium to the measurement system. The photodetector detects light intensity changes that correlate with decolorization progress, providing an objective intermediate signal that bridges the chemical reaction and the measurement outcome.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If sensor method measuring conductivity at different positions is used, then objective measurements can be obtained, but the sensors influence the dynamic flow path and measurement accuracy depends on sensor position and response time

Engineering Contradiction:
Improveobjectivity of measurementVSAvoidnumber and positioning of sensors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the measurement function from the bulk fluid by using a non-invasive optical detection approach. Instead of placing conductivity sensors throughout the reactor volume, a single photodetector measures light transmission through the medium, removing the need for multiple intrusive sensors while maintaining measurement capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the electrical conductivity measurement system with an optical measurement system. This substitution eliminates the need for multiple conductivity sensors and their complex positioning requirements, using light intensity measurement instead to achieve the same mixing time determination objective.

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

3Reliability

If confocal optical system with fluorescence detection is used, then noninvasive measurement is achieved, but the system is complex and expensive with multiple components including pinhole, lens, APD detector and light filters

Engineering Contradiction:
Improvenoninvasive measurement capabilityVSAvoidnumber of optical components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential measurement function from the confocal system - detecting light intensity changes during decolorization. By removing unnecessary components like pinholes, complex lens systems, and multiple filters, the invention retains the noninvasive optical measurement capability while dramatically simplifying the device architecture.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive, complex optical components with simpler, more affordable alternatives. Instead of an APD detector with associated optics, a standard photodetector is used that provides sufficient measurement capability at lower cost and complexity, making the system more accessible for routine use.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Loss of information

If frame-by-frame video analysis is used to determine mixing time, then visual documentation is obtained, but the process is time-consuming and subject to human error in determining when 95% decolorization is achieved

Engineering Contradiction:
Improvevisual record of processVSAvoidtime for analysis
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The patent implements continuous real-time measurement of light intensity during the decolorization reaction. Instead of capturing discrete video frames for later analysis, the photodetector continuously monitors the reaction progress, providing an uninterrupted data stream that immediately reflects the current mixing state without requiring post-processing time.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent replaces the manual video analysis process with automated photodetector measurement and digital signal processing. The system automatically converts light intensity changes into mixing time data, eliminating the need for human observers to manually analyze video frames and determine when decolorization thresholds are reached.

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

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

Provides accurate, real-time, and scalable mixing time determination across various bioreactor sizes, enhancing precision and efficiency by automating data capture and analysis.

Implementation Method 1

at least one photodetector... The processing unit is configured to receive signals from the photodetector... evaluate the signals received from the photodetector during a decolorization reaction

Methodology Applied
Scientific EffectPhotodetection: Photoelectric Effect

Data Source

PatentEP4700110A1Device arrangement and method for determining a mixing time in a vessel, especially in a bioreactor
Publication Date: 2026.02.25 SARTORIUS STEDIM DATA ANALYTICS AB
  • EP4700110A1 patent drawingFigure 1
  • EP4700110A1 patent drawing

AI summary

A device arrangement for determining a mixing time in a vessel (10), especially in a bioreactor, is provided. The device arrangement comprises a vessel (10), especially a bioreactor, including a mixing mechanism (12) for mixing a medium (14) in the vessel (10). The device arrangement further comprises at least one light source (16), at least one photodetector (18), and a processing unit (20). The processing unit (20) is configured to receive signals from the photodetector (18) when the light source (16) and the mixing mechanism (12) are active. The processing unit (20) is configured to evaluate the signals received from the photodetector (18) during a decolorization reaction in a medium (14) contained in the vessel (10) to determine a mixing time. Preferably, the light source (16) is arranged outside the vessel (10). The vessel (10) is transparent or includes at least one window that is transparent with respect to light emitted by the light source (16). The vessel (10) is arranged at least partly between the light source (16) and the photodetector (18) so that light from the light source (16) can reach the photodetector (18) when the vessel (10) is empty.