Vacuum Microwave Drying of Organic Products
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Solution Overview
Problem
Existing methods for drying and puffing organic, water-moist products, such as fruit and vegetables, face challenges in achieving high-quality, cost-effective results due to issues like browning, burning, and inefficiencies in industrial-scale implementation, particularly with microwave vacuum drying methods.
Innovation Solution
A method and device that involve introducing water-moist products into a chamber, evacuating to reduce pressure, applying microwave energy for puffing, alternating pressure to stabilize the product, and using infrared radiation at negative pressure for final drying, while controlling temperature and ambient pressure to prevent burning and ensure uniform heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If microwave vacuum drying is used to achieve high-quality products, then product quality and nutrient preservation are improved, but browning and burning effects occur during the drying process
Solution Approach 1:
The drying process is divided into two distinct stages: a first drying stage in vacuum using microwave energy, and a second drying stage in atmospheric pressure using infrared radiation. This segmentation allows each stage to be optimized for its specific function, preventing browning and burning while achieving high product quality.
Solution Approach 2:
The patent changes the pressure parameter between the two drying stages - from vacuum (first stage) to atmospheric pressure (second stage). This parameter change prevents browning and burning effects that occur during single-stage vacuum microwave drying, while maintaining high product quality and nutrient preservation.
2Ease of manufacture
If conventional drying methods are used to reduce costs, then cost-effectiveness is improved, but product quality deteriorates
Solution Approach 1:
The drying process is segmented into two stages with different energy sources and pressure conditions. The first stage uses microwave energy in vacuum for rapid water removal, while the second stage uses infrared radiation at atmospheric pressure for final drying. This segmentation achieves high product quality while maintaining cost-effectiveness by optimizing energy usage in each stage.
Solution Approach 2:
By changing pressure parameters between stages (vacuum to atmospheric) and using different energy sources (microwave to infrared), the process achieves superior product quality compared to conventional single-stage drying, while managing energy consumption efficiently to maintain cost-effectiveness.
3Shape
If pressure is reduced rapidly to achieve puffing, then puffing effect is improved, but product stability decreases
Solution Approach 1:
The patent applies periodic pressure variations during the drying process, alternating between vacuum conditions (for puffing) and atmospheric pressure (for stabilization). This periodic action allows the product to undergo puffing when pressure is reduced, then stabilize when pressure is increased, achieving both puffing effect and product stability.
Solution Approach 2:
The pressure parameter is changed dynamically during the process - rapidly reduced for puffing, then increased for stabilization. This controlled parameter change sequence allows the product to achieve the desired puffing effect while maintaining stability through subsequent pressure increase and inert gas atmosphere.
4Productivity
If microwave energy is applied continuously for drying, then drying speed is improved, but energy efficiency decreases due to burning risks
Solution Approach 1:
The drying process is segmented into two stages with different energy sources. The first stage uses microwave energy in vacuum for rapid water removal, achieving high drying speed. The second stage uses infrared radiation at atmospheric pressure for final drying, which is more energy-efficient and prevents burning. This segmentation optimizes both drying speed and energy efficiency.
Solution Approach 2:
By changing the energy source from microwave to infrared radiation between stages, and adjusting pressure parameters, the process achieves rapid initial drying followed by efficient final drying. This parameter change sequence prevents energy waste from burning while maintaining high productivity.
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 results in a higher-quality, cost-effective product with improved stability and extended shelf life by preventing browning and optimizing energy usage, while maintaining nutrient preservation and uniform heating.
Implementation Method 1
supplying microwave energy from a microwave source in order to increase the temperature and puff the water-moist product
Implementation Method 2
evacuating the first chamber to a first reduced ambient pressure... pump away emerging vapors
Implementation Method 3
evacuating the first chamber to a first reduced ambient pressure
Implementation Method 4
final drying of the product in a second chamber while supplying infrared radiation
Data Source
AI summary
A method of drying and buffering organic moist products, particularly food items. Introducing the product into a first chamber, bringing the first chamber to a first reduced ambient pressure, feeding microwave energy from a microwave source so as to increase the temperature and buffer the moist product, and increasing the reduced ambient pressure to a less reduced second ambient pressure multiple times and subsequently reducing the ambient pressure to the first reduced ambient pressure. Wherein the increase of the ambient pressure is carried out faster than the reduction thereof, followed by a final drying of the product in a second chamber while feeding infrared radiation at a third (reduced) ambient pressure. Subsequently, the product is cooled and discharged into the atmosphere. Thus, increased product quality, in particular a more consistent and more stable product is obtained.