Microwave Cooking Power Control Using Surface Layer Temperature
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Solution Overview
Problem
Existing microwave cooking methods fail to prevent undesirable weight loss and incrustation when cooking different food items, as they rely solely on the highest temperature sensed, neglecting the temperature gradient and thermal conductivity, leading to inefficient power adjustment.
Innovation Solution
A method that adjusts microwave power based on a temperature threshold (60°-100° C) specific to the food's characteristics and sensor placement, with multiple temperature sensors monitoring the surface layer temperature, switching between full and reduced power phases to maintain optimal cooking conditions, and accounting for temperature changes over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If microwave power is reduced based solely on the highest temperature sensed, then the temperature gradient between surface and core is reduced, but weight loss and incrustation occur
Solution Approach 1:
The patent applies local quality by monitoring temperature at multiple specific locations (surface layer and core) rather than using a single temperature sensor. Different temperature thresholds are applied to different locations: the surface layer threshold (60-100°C) prevents incrustation while the core temperature ensures thorough cooking. This localized temperature management resolves the contradiction by allowing power reduction only when the surface layer reaches critical temperatures, not when the core is still cooling.
Solution Approach 2:
The patent changes the control parameter from a single maximum temperature threshold to multiple location-specific thresholds. The surface layer temperature threshold (60-100°C) is introduced as a new control parameter that triggers power reduction earlier than core temperature-based control, preventing incrustation while maintaining cooking efficiency. This parameter change allows the system to distinguish between acceptable core temperature rise and harmful surface temperature rise.
2Object-affected harmful factors
If microwave power is reduced early to prevent surface overheating, then incrustation is prevented, but cooking time increases
Solution Approach 1:
The patent applies preliminary action by monitoring and controlling the surface layer temperature before the core temperature reaches dangerous levels. The surface layer temperature sensor detects overheating trends early in the cooking process, allowing power reduction to be triggered proactively rather than reactively. This preliminary control prevents incrustation from developing while minimizing cooking time extension, as the intervention occurs only when surface temperature approaches the 60-100°C threshold.
Solution Approach 2:
The patent implements feedback control by continuously monitoring surface layer temperature and adjusting microwave power accordingly. When the surface layer temperature reaches the 60-100°C threshold, power is reduced; when it drops below the threshold, power can be increased again. This dynamic feedback mechanism prevents incrustation while optimizing cooking time, as the system responds to real-time temperature conditions rather than using fixed timing or single-point temperature control.
3Measurement precision
If multiple temperature sensors are used to monitor surface layer temperature, then precise power control is achieved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the temperature monitoring function into two distinct sensor locations: a surface layer sensor (1-40 mm depth) and a core sensor. Each sensor serves a specific monitoring purpose, with the surface sensor detecting incrustation risks and the core sensor ensuring thorough cooking. This segmentation provides precise surface temperature control without requiring complex multi-sensor arrays, as only two strategically positioned sensors are needed to capture the critical temperature gradients.
Solution Approach 2:
The patent uses the surface layer temperature sensor as an intermediary between the microwave source and the core food. Rather than directly monitoring core temperature for power control, the system uses surface temperature as an indirect indicator of overall cooking state and incrustation risk. This intermediary approach simplifies control logic, as surface temperature responds more quickly to power changes and provides earlier warning of problematic conditions, reducing the need for complex core temperature-based control algorithms.
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 precise control of microwave power, reducing cooking time while minimizing weight loss and incrustation by ensuring the surface layer temperature is managed within safe limits, thereby enhancing cooking efficiency and food quality.
Implementation Method 1
a cooking appliance with a cooking chamber, in particular a microwave oven, with at least one microwave source
Implementation Method 2
at least one temperature sensor which can be inserted at least partially into the food to be cooked in the cooking chamber
Data Source
AI summary
The method involves heating a surface layer of a cooking product maximum to a temperature threshold value by applying microwaves in a cooking phase. Microwave application is changed in another cooking phase in comparison to the former phase by reducing microwave power emitted from a microwave source. A phase change is caused so that surface layer temperature is not increased to the temperature threshold value after elapse of time and not lowered when reducing the microwave power of the microwave source by turning off the microwave source. An independent claim is also included for a cooking device comprising a cooking chamber.