Microwave Cooking Power Control for Uniform Core and Surface Heating
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Solution Overview
Problem
Existing cooking technologies, particularly microwave ovens, face challenges in uniformly heating food due to the limited penetration depth of microwave radiation, leading to inefficient heating, where most heat is applied to the surface rather than the interior, and fail to account for food-specific properties like dielectric constants and temperature distributions.
Innovation Solution
A method that determines a first core temperature and a second surface temperature at spatially distinct locations within the food, calculates a reference variable to characterize the average temperature, and adjusts microwave power based on food-specific parameters such as penetration depth, dielectric properties, and absorption characteristics to optimize heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If microwave radiation is used for heating food, then heating speed is improved, but temperature distribution uniformity deteriorates due to limited penetration depth
Solution Approach 1:
The patent implements dynamic adjustment of microwave power based on real-time temperature feedback from multiple sensors. The control unit continuously monitors temperature at different locations and adjusts power levels to maintain uniform heating, transforming the static microwave heating process into a dynamic controlled system that adapts to changing temperature distributions.
Solution Approach 2:
The patent applies different microwave power levels to different regions of the food based on local temperature conditions. By using multiple temperature sensors at different locations and adjusting power accordingly, the system creates localized heating zones that compensate for the limited penetration depth, ensuring each region receives appropriate energy input for uniform overall heating.
2Productivity
If high microwave power is applied to heat food quickly, then productivity is improved, but surface overheating and drying worsen
Solution Approach 1:
The patent employs a feedback control system where temperature sensors continuously monitor the food's temperature at multiple locations, and the control unit adjusts microwave power based on this feedback. This closed-loop control prevents surface overheating by detecting temperature rise and reducing power before drying or overcooking occurs, while maintaining high overall cooking efficiency.
Solution Approach 2:
The patent uses multiple temperature sensors placed at different locations within the food to monitor temperature distribution. By measuring temperature at multiple points rather than a single location, the system can detect surface temperature rise earlier and adjust power accordingly, preventing surface damage while maintaining efficient bulk heating.
3Loss of time
If microwave power is increased to reduce cooking time, then loss of time is reduced, but energy loss increases due to inefficient heat distribution
Solution Approach 1:
The patent uses real-time temperature feedback from multiple sensors to optimize microwave power delivery. The control unit adjusts power levels based on actual heating progress, ensuring energy is applied efficiently when needed and reduced when heating is sufficient. This prevents energy waste from continued high-power operation after the food is adequately heated, while maintaining short cooking times.
Solution Approach 2:
The patent dynamically changes microwave power parameters based on temperature measurements and food properties. By adjusting power levels according to real-time conditions and predetermined optimal curves, the system achieves rapid heating when necessary while minimizing energy waste during later stages, optimizing the balance between cooking time and energy 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
This approach allows for more uniform heating by dynamically adjusting microwave power, ensuring that both surface and core temperatures are effectively managed, leading to improved cooking results and preventing surface drying or overcooking.
Implementation Method 1
A major advantage of using microwave radiation is the direct absorption of the microwave radiation in the food, which immediately leads to heating
Implementation Method 2
heating of the food to be cooked takes place during microwave irradiation to a large extent in a surface area of the food to be cooked
Implementation Method 3
the heating inside the food, ie in the area of the core temperature, is essentially predetermined by heat diffusion within the food
Data Source
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AI summary
The method involves determining the core temperature of a cooking product at first location and determining the warmest temperature/surface temperature of food to-be-cooked at second location which is at spatial distance from first location. A characteristic of medium temperature of cooking reference value is determined by evaluating the temperatures and the spatial distance. The temperature dependent cooking product specific control parameter is determined from the reference value. The microwave power is adjusted in response to the control parameter. An independent claim is included for cooking apparatus.