Microwave Pasteurization Cooling Plate Prevents Package Bursting
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Solution Overview
Problem
Conventional microwave pasteurization of food in sealed packages faces challenges such as burst containers due to internal pressure from steam formation, requiring complex and costly systems for maintaining overpressure, and inefficient heating leading to unsatisfactory results, especially with solid foods and different food types.
Innovation Solution
A device and process utilizing a microwave chamber at atmospheric pressure with a conveyor belt and cooling system to dissipate overpressure by cooling the package surface below the water vapor condensation point, allowing for continuous operation without external pressure and using standard containers, ensuring homogeneous heating and maintaining food safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If microwave heating is used for pasteurization of sealed packages, then heating time is reduced and pasteurization efficiency is improved, but internal pressure builds up causing package bursting
Solution Approach 1:
The package is divided into a base container and a separate flexible lid that can deform independently. This segmentation allows the lid to absorb pressure changes through deformation while the food contents undergo pasteurization, preventing package bursting during microwave heating
Solution Approach 2:
The patent changes the physical state of the package lid from rigid to flexible, allowing it to deform under pressure. This parameter change enables the package to withstand microwave heating without bursting, as the flexible lid can expand and contract with internal pressure changes
2Stability of the object's composition
If conventional heating methods are used, then homogeneous heating is achieved, but heating time is extended causing cooking effects and quality degradation
Solution Approach 1:
The microwave heating process uses periodic pulsing with intervals between heating bursts. This periodic action allows brief heating periods followed by rest periods, preventing continuous overheating and cooking effects while still achieving pasteurization within a short total time, thus preserving food quality
Solution Approach 2:
The flexible lid continuously deforms and relaxes during the heating process, continuously managing internal pressure. This continuous adaptation allows sustained microwave heating without package failure, achieving efficient pasteurization while maintaining food quality
3Object-affected harmful factors
If external overpressure is applied during microwave heating, then package bursting is prevented, but system complexity and operating costs increase
Solution Approach 1:
The package lid performs the pressure management function itself through its flexible properties. As the lid is made of deformable material, it automatically expands when internal pressure increases and contracts when pressure decreases, eliminating the need for external pressure control systems or monitoring devices
4Object-affected harmful factors
If ventilation openings are provided in packages, then pressure relief is achieved, but hermetic sealing is compromised causing contamination and leakage
Solution Approach 1:
The patent employs a flexible lid made of deformable material that acts as a dynamic seal. This flexible shell can deform to accommodate pressure changes during heating, providing pressure relief through deformation rather than venting, while maintaining hermetic sealing to prevent contamination and liquid leakage
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
Enables efficient pasteurization of food in sealed packages without bursting, reducing system complexity and costs, achieving homogeneous heating, and preserving food quality by preventing aroma and liquid leakage, suitable for various food types and containers.
Implementation Method 1
heating by means of microwaves, usually with a frequency of 2.450 GHz or 915 MHz
Implementation Method 2
The microwave energy is introduced at a frequency of 2.45 GHz or 915 MHz or a combination of both frequencies
Implementation Method 3
an overpressure in the packings (22) is dissolved by cooling and condensation of water vapor on an elevated surface of the packing (22), which is cooled by means of the cooling device (10)
Data Source
AI summary
Apparatus and method for pasteurizing food products and ready meals in hermetically sealed packages (22) by means of microwaves, comprising a microwave chamber (14); a lower conveyor belt (20) for the packages (22); an upper conveyor belt (18), extending substantially horizontally and vertically movable, and a microwave source (16) located below the lower conveyor belt (20), the microwave chamber (14) being under atmospheric ambient pressure. The apparatus comprises a cooling plate (10) in close contact with the upper conveyor belt (18) so that during microwave heating the top of the package (22) is cooled to below the condensation point of water vapor and overpressure in the package is avoided.