Freeze-Drying Thermal IR Control for Uniform Sublimation

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Solution Overview

Problem

Current freeze-drying methods are inefficient and lack precise control, leading to slow processing times and variability in batch quality, particularly during the experimental and development phases, due to limitations in optimizing the freezing cycle and controlling the sublimation process.

Innovation Solution

A method and apparatus utilizing thermal IR imaging to monitor and control the sublimation process by calculating temperature values on the container wall, adjusting power supply based on calculated maximum product temperature and dynamic safety margins, and rotating the container to ensure uniform energy distribution, thereby improving process efficiency and product quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional batch freeze-drying is used to process multiple containers simultaneously, then productivity is improved through batch processing, but manufacturing precision deteriorates due to local variations in process conditions that cannot be compensated

Engineering Contradiction:
Improvebatch processing capacityVSAvoidproduct quality uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system divides the batch processing into individual container-level control units. Each container is equipped with independent sensors and heating elements, allowing the batch to be segmented into independently controllable units. This enables simultaneous processing of multiple containers while maintaining uniform quality through individualized control of temperature, pressure, and sublimation rate for each container.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the sublimation process is accelerated to reduce processing time, then productivity is improved, but reliability deteriorates due to risk of overheating the product

Engineering Contradiction:
Improveprocessing speedVSAvoidproduct temperature control
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system implements real-time feedback control by continuously monitoring temperature, pressure, and sublimation front position in each container. The control unit receives data from sensors and automatically adjusts heating power to maintain optimal sublimation rate while preventing overheating. This closed-loop feedback enables faster processing while ensuring product safety through dynamic adjustment of process parameters.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static batch processing to dynamic control where process parameters are continuously adjusted based on real-time conditions. Heating power, pressure, and temperature are dynamically modified during the sublimation process to optimize both speed and safety, allowing the system to adapt to changing conditions within each container.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If thermal imaging and real-time control systems are implemented, then manufacturing precision is improved through better process control, but device complexity increases

Engineering Contradiction:
Improveprocess control accuracyVSAvoidsystem component count
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system replaces complex mechanical control mechanisms with optical and electronic systems. Thermal imaging cameras detect temperature distributions without physical contact, and the control unit processes visual data to adjust heating elements. This substitution of mechanical systems with optical-electronic systems achieves precise control while reducing mechanical complexity through non-contact measurement and digital processing.

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

4Reliability

If continuous monitoring and adjustment of process parameters are implemented, then reliability is improved through better temperature control, but loss of time increases due to repeated measurements and adjustments

Engineering Contradiction:
Improvetemperature control accuracyVSAvoidmeasurement and adjustment cycle time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system implements continuous monitoring and adjustment rather than periodic measurements. Thermal imaging and sensor data are collected continuously, and the control unit makes real-time adjustments to heating power without interrupting the sublimation process. This continuous operation eliminates idle time between measurements and maintains optimal conditions throughout the process, improving reliability without significant time penalty.

Inventive Principle:
Principle #20Continuity of useful action

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 approach significantly reduces processing time while maintaining product quality by dynamically adjusting safety margins and ensuring uniform heating, resulting in improved throughput and consistent batch quality.

Implementation Method 1

capturing a thermal IR image of at least a portion of the container wall using at least one thermal IR camera; processing the thermal IR image by determining a plurality of temperature values associated with a plurality of points located on an outer surface of the container wall

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

controlling an amount of power supplied to at least a portion of the container based on the calculated maximum product temperature

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

a primary drying phase (sublimation)... forcing sublimation of ice crystals formed in the frozen composition... allowing the ice to change directly from a solid to a vapour state

Methodology Applied
Scientific EffectSublimation: Sublimation

Implementation Method 4

rotating the container to ensure uniform energy distribution

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3500811B1Method and apparatus for freeze-drying
Publication Date: 2020.12.23 RHEAVITA
  • EP3500811B1 patent drawingFigure 1~2B
  • EP3500811B1 patent drawingFigure 3A~3F
  • EP3500811B1 patent drawingFigure 4(A)~5

AI summary

A method of drying (sublimation or desorption) a frozen product stored in a container (703), comprising: a) capturing (1401) a thermal IR image of the container wall using a thermal IR camera (701); b) processing (1402) the thermal IR image by calculating temperature values of points located on the outer surface of the container wall; c) calculating (1403) a maximum temperature of the product in the container using a mathematical model that models heat flow and that models progress of the drying process; d) controlling an amount of power supplied to the container based on the calculated maximum product temperature (Tprod_max) and on a temperature safety_margin (Tsm). A freeze drying apparatus for performing said method. A container having a specific shape for use in such a process.