Semiconductor Microwave Freeze-Drying for Uniform Vacuum Heating
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Solution Overview
Problem
Conventional freeze-drying systems face inefficiencies in heat transfer under vacuum conditions, leading to a temperature gradient and reduced overall efficiency due to reliance on heat convection and emissivity of frozen products.
Innovation Solution
A device incorporating a microwave module based on semiconductor technology is used to supply energy for freeze-drying, allowing for controlled and uniform temperature management independent of pressure conditions, with microwave antennas arranged within the drying chamber to ensure efficient energy distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If heat transfer is performed under vacuum conditions using conventional methods (heat convection through gas and radiation), then the freeze-drying process can proceed, but the thermal conductivity decreases and heat transfer efficiency is reduced
Solution Approach 1:
The patent replaces conventional thermal radiation and convection mechanisms with microwave electromagnetic field heating. Instead of relying on thermal radiation from heating elements or convection through gas (which are inefficient under vacuum), the invention uses microwave radiation to directly heat the product and sublimation front, achieving efficient energy transfer under vacuum conditions without depending on gas phase thermal conductivity
Solution Approach 2:
The invention changes the heating parameter from thermal radiation/convection to microwave electromagnetic field interaction. By utilizing the dielectric properties of frozen materials at microwave frequencies, the system achieves direct volumetric heating of the product, fundamentally changing how energy is transferred and absorbed during the freeze-drying process under vacuum
2Temperature
If heat is supplied primarily through the base of the vessel, then the freeze-drying process can proceed, but a temperature gradient remains in the frozen product reducing efficiency
Solution Approach 1:
The patent replaces base heating through thermal conduction with microwave electromagnetic field heating. The microwave antennas positioned within or near the drying chamber generate electromagnetic fields that penetrate the frozen product, enabling uniform volumetric heating throughout the product rather than creating temperature gradients from base-to-top heating
Solution Approach 2:
The invention introduces microwave electromagnetic fields as an intermediary heating mechanism. The microwave field acts as a mediator that distributes energy uniformly throughout the frozen product volume, eliminating the need for direct thermal contact through the vessel base and the resulting temperature gradients
3Loss of energy
If heat transfer depends on heat convection through gas and emissivity of frozen products, then the freeze-drying process can proceed, but the process becomes inefficient under vacuum conditions
Solution Approach 1:
The patent substitutes inefficient thermal convection and radiation-based heating with microwave dielectric heating. Since microwave heating does not depend on gas phase convection or product surface emissivity, it maintains high energy efficiency under vacuum conditions where conventional thermal transfer mechanisms are compromised
Solution Approach 2:
The invention changes the energy transfer parameter from thermal convection/radiation to microwave electromagnetic field interaction. This parameter change eliminates dependence on gas density and product emissivity, allowing efficient energy transfer directly to the frozen product regardless of vacuum conditions
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 microwave-based energy supply enhances the efficiency of the freeze-drying process by providing a more uniform and controlled heat input, reducing the dependence on conventional heat transfer methods and improving the overall efficiency of the process.
Implementation Method 1
a microwave module based on semiconductor technology is provided, which is used to generate microwaves for supplying energy to products arranged in the drying chamber during the freeze-drying process
Implementation Method 2
The microwave module comprises at least one microwave antenna based on semiconductor technology, in particular at least one semiconductor antenna
Implementation Method 3
The microwave module comprises at least one microwave antenna based on semiconductor technology, in particular at least one semiconductor antenna
Implementation Method 4
Freeze-drying, also referred to as lyophilization or sublimation drying, is a method for carefully drying these products
Implementation Method 5
During the primary drying stage, pressure is reduced and the solvent contained in the product sublimates at low temperatures
Implementation Method 6
The freezing there is also referred to as crystallization. The onset of freezing is called seed crystal formation or nucleation
Data Source
AI summary
The invention relates to a device and a method for freeze-drying products, wherein products are arranged in a drying chamber (2) for a freeze-drying process, wherein energy is supplied to the products arranged in the drying chamber (2) by means of microwaves at least during some parts of the freeze-drying process, and wherein the microwaves are generated by at least one microwave module (6) based on semiconductor technology. The invention also relates to the use of a microwave module (6) based on semiconductor technology in a freeze-drying process.