Bulk Freeze Drying via Spray Freezing and Agitated Vacuum
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Solution Overview
Problem
Current bulk freeze drying methods for pharmaceutical and other bulk powder products face challenges such as inefficient heat transfer, manual handling risks, and the need for secondary milling to achieve uniform particle sizes, particularly in aseptic conditions, where tray-based systems are not optimized and consume significant resources like nitrogen gas.
Innovation Solution
A freeze drying system comprising a freezing chamber with spray nozzles for atomizing the product and a freezing agent, a vacuum drying chamber with agitating mechanisms, and a condensing chamber, allowing for spray-freezing and vacuum drying without trays, minimizing handling and optimizing heat transfer through continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tray-based freeze drying is used for bulk product, then aseptic conditions are maintained, but heat transfer efficiency is poor and handling is difficult
Solution Approach 1:
The patent changes the physical state and arrangement of the product from bulk powder in trays to atomized liquid droplets in airborne suspension. This parameter change enables direct exposure of all product surfaces to the drying environment, dramatically improving heat and mass transfer efficiency while maintaining aseptic conditions through controlled atomization and vacuum sealing.
Solution Approach 2:
The patent uses pneumatic atomization to disperse the liquid product into fine droplets that are suspended in air within the sealed chamber. This pneumatic system enables efficient heat transfer through the droplet surface area while maintaining aseptic conditions through the closed vacuum environment, eliminating the need for manual tray handling.
2Ease of operation
If manual handling of trays is used, then product can be loaded and removed, but risk of liquid spill and handling loss increases
Solution Approach 1:
The patent replaces the mechanical tray-handling system with an airborne atomization system. The liquid product is atomized into droplets that are suspended and processed in place within the sealed chamber, eliminating manual tray manipulation entirely. Product is loaded as liquid and removed as dried powder through automated mechanisms, eliminating spill risks associated with manual tray handling.
3Manufacturing precision
If spray freezing is used to create fine particles, then particle size uniformity is achieved, but additional milling is required
Solution Approach 1:
The patent performs preliminary particle size control during the atomization and freeze-drying process itself. By controlling the atomization parameters and drying conditions, the desired particle size distribution is achieved directly in the dried powder, eliminating the need for subsequent milling operations. The preliminary action of controlled atomization creates the final particle morphology required.
4Stability of the object's composition
If batch processing in trays is used, then product stability is maintained, but cycle time is extended
Solution Approach 1:
The patent enables continuous atomization of liquid product into the sealed vacuum chamber, maintaining uninterrupted freeze-drying operation. Multiple batches can be processed in sequence or simultaneously in different zones, eliminating the idle time associated with loading and unloading trays between batches. The continuous action maintains product stability through controlled environmental conditions while dramatically reducing overall cycle time.
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 system enables efficient, aseptic bulk freeze drying with reduced handling, minimized energy consumption, and uniform particle sizes, maintaining product integrity and reducing cycle times, while allowing for continuous operation and easier product collection.
Implementation Method 1
The at least one spray nozzle is connected for spraying the bulk product and a freezing agent, and is configured to spray the bulk product and the freezing agent in the interior of the freezing chamber to create a spray-frozen powder
Implementation Method 2
spray the bulk product and the freezing agent in the interior of the freezing chamber to create a spray-frozen powder
Implementation Method 3
The spray-frozen powder is agitated under the vacuum pressure in the vacuum drying chamber using an agitating mechanism to bring portions of the spray-frozen powder into and out of contact with a wall of the vacuum drying chamber
Implementation Method 4
agitated under the vacuum pressure in the vacuum drying chamber using an agitating mechanism to bring portions of the spray-frozen powder into and out of contact with a wall of the vacuum drying chamber
Implementation Method 5
the spray-frozen powder is agitated under the vacuum pressure in the vacuum drying chamber using an agitating mechanism to bring portions of the spray-frozen powder into and out of contact with a wall of the vacuum drying chamber. During the agitating, the spray-frozen powder is heated to cause sublimation of frozen liquid
Implementation Method 6
a condensing chamber in communication with the drying chamber and comprises surfaces for condensing a vapor from exhaust gas received from the drying chamber
Data Source
AI summary
A freeze dryer processes bulk powder products. The freeze dryer freezes the product by mixing an atomized spray of product with sterile liquid nitrogen. The resultant powder is freeze dried in a vessel, and the vessel contents is agitated to maintain product contact with heated vessel wall and to prevent agglomeration.