Air Cycle Freeze-Drying System for High-Speed Freezing
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Solution Overview
Problem
The existing freeze-drying systems face challenges in achieving high productivity and cleanliness, particularly when using expensive and clean liquid nitrogen, which results in long freezing cycles and complex system configurations, especially when trying to freeze objects requiring hygiene.
Innovation Solution
A freeze-drying system utilizing an air cycle as the refrigerant, with a cooling device that generates cold and a cold air supplying mechanism to precool the freeze-drying chamber, allowing for flexible temperature control and efficient freezing by staging the target temperatures, thereby shortening the freezing period and improving productivity while maintaining high cleanliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If liquid nitrogen is used as refrigerant to achieve high cleaning and high freezing capacity, then the freezing speed is improved, but the system complexity and operational complexity increase due to need for external supply and storage
Solution Approach 1:
The patent extracts the refrigerant function from external liquid nitrogen supply and transfers it to an internal air cycle system. The refrigerant circulation path is taken out from the object and led to the cooling device, where heat exchange occurs, and the cooled refrigerant is returned to the object, eliminating the need for external liquid nitrogen storage and supply infrastructure
Solution Approach 2:
The patent introduces air as an intermediary refrigerant medium that circulates between the object and the cooling device. This air cycle system acts as a mediator that transfers thermal energy without requiring direct contact with liquid nitrogen, thereby simplifying the system while maintaining high freezing capacity
2Productivity
If liquid nitrogen is used to achieve high freezing capacity, then the freezing period is shortened, but the operational complexity increases due to handling requirements
Solution Approach 1:
The patent implements a self-service refrigeration system where the air cycle automatically circulates between the object and cooling device without external intervention. The system self-regulates the refrigerant flow and heat exchange process, eliminating the need for manual liquid nitrogen handling, storage monitoring, and supply operations
Solution Approach 2:
The patent merges the refrigerant circulation function with the existing freeze-drying chamber structure. The air cycle system is integrated into the chamber, combining the cooling function with the vacuum drying environment, thereby simplifying operations by eliminating separate liquid nitrogen handling procedures
3Reliability
If conventional cooling systems are used with multiple heat sources, then the system complexity increases, but the freezing efficiency is maintained
Solution Approach 1:
The patent makes the air cycle cooling device universal by enabling it to perform multiple functions: it serves as the primary refrigerant for high-speed freezing, acts as a heat exchange medium, and integrates with the vacuum drying environment. This single multi-functional system replaces what would traditionally require multiple separate cooling devices and refrigerant management systems
Solution Approach 2:
The patent segments the cooling function into distinct components: the cooling device that generates cold, the air cycle that distributes it, and the heat exchange unit that applies it to the object. This segmentation allows each component to be optimized independently while working together as a simplified integrated system with high freezing efficiency
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
The system achieves high freezing capacity with a simple configuration, reduces freezing time significantly, and ensures high cleanliness without the need for external refrigerant supply, thereby enhancing productivity and reducing costs.
Implementation Method 1
a cooling device 3 which generates the cold with an air cycle in which air is used as a refrigerant
Implementation Method 2
a cold air supplying mechanism 40 which supplies precooled air into the freeze-drying chamber 2
Implementation Method 3
a freeze-drying chamber 2 accommodating a heat exchange unit 12 which causes heat exchange between the refrigerant and the object
Implementation Method 4
collecting the sublimated moisture with a cold trap 4 cooled in advance
Implementation Method 5
freezing the object by setting a temperature in the freeze-drying chamber to a second temperature lower than the first temperature
Data Source
AI summary
A freeze-drying system is provided in which freeze-drying is performed by sublimating moisture frozen by cooling an object and collects the sublimated moisture with a cold trap. The freeze-drying system includes: a cooling device which generates cold with an air cycle in which air is used as a refrigerant; a freeze-drying chamber accommodating a heat exchange unit which causes heat exchange between the refrigerant and the object; a cold air supplying mechanism which supplies precooled air into the freeze-drying chamber; and a control unit which controls a cooling capacity of the cooling device. The control unit adjusts the temperature in the freeze-drying chamber to a predetermined target temperature by controlling an amount of the cold generated in the cooling device. The cold air supplying mechanism includes an air supply line through which air, as the refrigerant that circulates in the air cycle, is partially introduced into the freeze-drying chamber.