Cooktop Capacitance Electrodes for Boil-Over Detection
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Solution Overview
Problem
Conventional cooking devices struggle to accurately detect liquid boiled over from a container in various directions, leading to potential electrode damage and user inconvenience.
Innovation Solution
A cooking device with arc-shaped electrodes on its lower surface, a capacitance detection system, and a boil-over determination mechanism that stops or reduces heating when liquid is detected, ensuring accurate detection and preventing electrode damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrodes are provided on the upper surface of the top plate to detect boiled over liquid, then the liquid boiled over can be detected, but the electrodes may be damaged which decreases detection accuracy
Solution Approach 1:
The patent inverts the conventional electrode placement by positioning electrodes on the lower surface of the top plate instead of the upper surface. This allows the electrodes to detect boiled over liquid through the top plate material without being directly exposed to the liquid, thus preventing electrode damage while maintaining detection accuracy. The detection function is achieved by sensing changes in the dielectric properties of the top plate material when liquid is present on its upper surface.
Solution Approach 2:
The top plate material acts as an intermediary between the boiled over liquid and the electrodes. The liquid on the upper surface of the top plate modifies the dielectric properties of the plate material, which in turn changes the capacitance detected by the electrodes on the lower surface. This intermediary mechanism allows indirect detection of the liquid without direct contact between the electrodes and the liquid.
2Measurement precision
If electrodes are provided only on the front side of the container to detect boiled over liquid, then the liquid boiled over onto the front side can be detected, but liquid boiled over in other directions cannot be detected
Solution Approach 1:
The patent makes the detection system universal by providing electrodes along the entire periphery of the heating device rather than only on the front side. This peripheral arrangement allows the detection system to detect boiled over liquid regardless of the direction in which it flows, making the detection function versatile and effective for liquid spillage in any direction around the container.
3Ease of operation
If touch keys are provided on the front side of the cooking device, then user operation can be detected, but it becomes impossible to discriminate between user operation and liquid boiled over
Solution Approach 1:
The patent separates the user interface function from the detection function by placing touch keys on the front side of the cooking device body while positioning detection electrodes on the lower surface of the top plate. This spatial separation in different dimensions allows both functions to coexist without interference - the touch keys remain accessible for user operation while the electrodes accurately detect liquid without being affected by finger contact with the front panel.
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
The device effectively detects liquid boiled over in multiple directions with high accuracy, preventing electrode damage and enhancing user safety and convenience by stopping or reducing heating output when necessary.
Implementation Method 1
a capacitance detection device for detecting changes in capacitance of the electrodes
Data Source
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AI summary
The cooking device includes a top plate 2 on which containers 30 are to be placed, heating devices 5L, 5R provided under the top plate 2, electrodes 15, 16, 17 provided on a lower surface of the top plate 2, capacitance detection devices 18, 19, 20 for detecting changes in capacitance of the electrodes 15, 16, 17, and a boil over determination device 31 for determining a liquid boiled over from the containers 30 on the basis of the changes in capacitance detected by the capacitance detection devices 18, 19, 20 in heating operations of the heating devices 5L, 5R. The electrodes 15, 16, 17 have a plurality of arc-shaped detection parts 15a, 16a, 17a provided along periphery of each of the heating devices 5L, 5R.