Internal Radiation Heating for Freeze-Drying
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Solution Overview
Problem
Conventional freeze-drying methods face inefficiencies due to the need for significant temperature changes in cooling and heating media, leading to slow processing times and reduced productivity, as well as inefficient heat transmission and potential loss of ice lining during the freeze-drying process.
Innovation Solution
The method involves supplying a liquid material to be dried onto a frozen surface within a vertical tube, where it is frozen and then subjected to radiation heat from internal heating means, allowing for efficient sublimation without melting, and utilizing a vacuum to enhance heat transfer and maintain efficient drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional heating means is used to heat the frozen dried material, then the heating process can be completed, but the heating efficiency is low and the processing time is long
Solution Approach 1:
The patent inverts the conventional heating approach by placing the heating means inside the vertical tube rather than outside. This internal placement allows radiation heat to directly reach the frozen dried material, eliminating the need for heat to travel through the tube wall and significantly improving heating efficiency and reducing processing time.
Solution Approach 2:
The patent replaces conventional conductive heating through the tube wall with radiation heating from an internal source. This substitution of heating mechanism allows direct energy transfer to the frozen material, overcoming the inefficiency of heat conduction through the tube wall and achieving rapid freeze-drying.
2Quantity of substance
If the vertical tube is formed into a large shape, then the capacity is increased, but the heat transmission efficiency is reduced
Solution Approach 1:
By inverting the heating arrangement from external to internal, the patent enables radiation heat to directly reach the material regardless of tube size. This internal radiation heating mechanism maintains high heat transmission efficiency even in large-diameter tubes, allowing increased material capacity without sacrificing heating efficiency.
3Device complexity
If the cooling medium temperature is significantly changed between freezing and freeze-drying processes, then the phase change can be achieved, but the temperature control becomes difficult and productivity is reduced
Solution Approach 1:
The patent separates the freezing and heating functions spatially by placing the heating means inside the tube while the cooling means remains external. This inversion allows independent control of temperature profiles: the external cooling medium can be optimized for freezing, while the internal radiation heating provides controlled heating during freeze-drying, simplifying temperature control and improving productivity.
4Ease of operation
If ice lining is formed on the inner surface, then the dried material can be easily scraped off, but the ice lining may be heated and sublimated before the water content in the dried material is sublimated
Solution Approach 1:
By placing the heating means inside the vertical tube, the patent ensures that radiation heat directly reaches the frozen dried material and the ice lining simultaneously. This internal heating allows the ice lining to be heated and sublimated in controlled manner during the freeze-drying process, preventing premature disappearance and ensuring stable contact between the heating source and the material throughout the process.
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 enables rapid and efficient freeze-drying by minimizing conductive heat loss and ensuring consistent heat delivery, significantly increasing production efficiency and maintaining product quality.
Implementation Method 1
freezing the liquid material to be dried onto an inner circumferential surface of a vertical tube
Implementation Method 2
radiation heat is supplied from internal heating means arranged in the vertical tube to the frozen dried material
Implementation Method 3
the frozen-water content in the dried material is sublimated from an inner surface side facing a pressure-reduced space
Implementation Method 4
utilizing a vacuum to enhance heat transfer and maintain efficient drying
Data Source
Figure 1
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AI summary
A material to be dried is frozen and is efficiently freeze-dried in a short time, thereby increasing production efficiency. A freeze-drying apparatus includes a vertical tube (2) having an inner circumferential surface formed with a frozen surface (2a), a liquid-supply device (5) for supplying a liquid material to be dried (47) onto the frozen surface (2a), a freezing device (10) arranged around the vertical tube (2) and intended for cooling the frozen surface (2a), a pressure-reduction device (12) which puts an interior area of the vertical tube (2) into a state of vacuum, and an internal heating device (41) in the vertical tube (2). The internal heating device (41) is arranged in the vertical tube (2) along a center axis thereof, and has an outer surface formed with a vertically long circular-cylindrical radiation surface (43). The liquid material to be dried (47) supplied from the liquid-supply device (5) is sprinkled onto the frozen surface (2a), and the frozen surface (2a) is cooled to freeze the dried material (47) into a shape of a pipe. Then, the interior area of the vertical tube (2) is pressure-reduced to supply radiation heat from the internal heating device (41) to the dried material (47) for freeze-drying the dried material (47).