Microwave Steam-Sensing Control for No-Load and Overload Cooking
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Solution Overview
Problem
Drawer-type microwave ovens face challenges in accurately controlling cooking time due to the absence of weight sensors, leading to potential overcooking or undercooking, as humidity sensors struggle with variations in food quantity and placement, increasing manufacturing costs and complexity.
Innovation Solution
A method using a humidity sensor to detect steam volume and adjust cooking duration by establishing minimum and maximum steam curves, with safety factors, to prevent overheating and underheating, allowing for accurate cooking even without a weight sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a weight sensor is used to accurately control cooking duration, then cooking precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the weight sensing function from a dedicated weight sensor and implements it through the existing humidity sensor by detecting steam generation characteristics. This eliminates the need for a separate weight sensor while maintaining cooking precision for foods within a specific weight range.
Solution Approach 2:
The humidity sensor is made multi-functional by using it for both its original humidity detection purpose and for inferring food weight through steam generation patterns. This universal approach allows one sensor to serve multiple functions, reducing overall device complexity.
2Ease of manufacture
If a humidity sensor is used to detect cooking state, then manufacturing cost is reduced, but measurement precision deteriorates due to variations in food quantity and placement
Solution Approach 1:
The system implements feedback control by continuously monitoring steam generation through the humidity sensor and adjusting cooking duration based on detected steam patterns. This feedback mechanism compensates for variations in food quantity and placement, improving measurement precision while maintaining cost-effectiveness.
Solution Approach 2:
The patent changes the interpretation parameters of the humidity sensor readings by establishing relationships between steam generation rates and food weight. By transforming how humidity data is analyzed rather than changing the sensor itself, the system maintains low manufacturing cost while improving measurement precision through sophisticated parameter interpretation.
3Reliability
If cooking duration is extended to accommodate larger food quantities, then underheating is prevented, but overheating occurs for smaller food quantities
Solution Approach 1:
The cooking duration is made dynamic rather than fixed. The system continuously adjusts cooking time based on real-time steam generation detection, allowing the cooking process to adapt to actual food quantity and heating rate. This dynamic adjustment prevents both underheating and overheating across different food quantities.
Solution Approach 2:
The system implements early termination of cooking when sufficient heating is detected through steam generation patterns. By allowing the cooking process to complete quickly when food quantity is small or heating is sufficient, the system prevents overheating while ensuring adequate cooking when needed.
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 method ensures precise cooking control, preventing overheating in small quantities and underheating in large quantities, while reducing manufacturing costs and complexity by relying solely on humidity sensors.
Implementation Method 1
a microwave heating unit 14 for radiating microwaves to heat an object placed in the heating chamber 3
Implementation Method 2
a humidity sensor 11 that detects a steam volume in the heating chamber 3
Data Source
AI summary
In a method of controlling a heating cooking apparatus, when a generated steam volume at a forced finish time Tn−1 determined based on a minimum volume-minimum steam curve does not reach a minimum steam volume B1 determined based on a slowly rising maximum volume-maximum steam curve, the generated steam volume is smaller than in the case of a food having a maximum weight. Therefore, it can be judged that heating is performed in a no-load condition with an exceedingly small generated steam volume, and the operation of the heating cooking apparatus is forcedly stopped. When a generated steam volume at a maximum detection time Tm+1 does not reach a standard steam volume A determined based on the maximum volume-maximum steam curve, it is judged that a large amount of food exceeding a maximum amount is being heated and the operation of the heating cooking apparatus is forcedly stopped.