Electric heater and cooking appliance having same
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Solution Overview
Problem
Existing plane heating elements in electric stoves have high electrode resistance, leading to local heating and potential hot wire breakdown due to high current density differences, especially when multiple electrodes are connected in a limited area.
Innovation Solution
The electric heater features a plane heating element with thicker electrode and bridge sections compared to the pattern tracks, reducing resistance and preventing local heating by configuring the electrode portion to generate heat at 200°C or less and the bridge to generate heat at 500°C or less, thereby ensuring uniform heating and preventing insulation breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode is configured to be much wider than the width of the heating pattern to achieve low resistance, then the electrode resistance is reduced, but the available area for multiple electrodes and patterns is limited
Solution Approach 1:
The patent transitions from two-dimensional planar electrodes to three-dimensional raised electrodes with controlled height (0.1-1.0 mm). This vertical dimension allows the electrodes to achieve lower resistance through increased cross-sectional area without occupying more horizontal space, thereby resolving the contradiction between electrode resistance and available heating area.
Solution Approach 2:
The patent changes the geometric parameters of the electrode by controlling its height within a specific range (0.1-1.0 mm). This parameter adjustment optimizes the balance between electrical resistance (requiring larger cross-section) and spatial constraints (limiting horizontal expansion), enabling low resistance while preserving heating area.
2Temperature
If a single hot wire is used in a limited area to heat to high temperatures, then the heating temperature is achieved, but local heat generation occurs due to current density differences causing hot wire breakdown
Solution Approach 1:
The patent applies different geometric properties to different parts of the heating element: the heating pattern maintains thin trace width for high resistance and heat generation, while the electrode portions are raised to create lower resistance. This local differentiation of structural quality prevents uniform current density distribution issues and eliminates hot wire breakdown while maintaining high heating temperatures.
Solution Approach 2:
The heating element is segmented into distinct functional zones: raised electrode portions for current input (low resistance) and thin heating pattern portions for heat generation (high resistance). This segmentation allows each zone to optimize its electrical properties independently, preventing the current density imbalances that cause hot wire breakdown.
3Adaptability or versatility
If multiple electrodes are connected in a limited area, then multi-pattern configurations are enabled, but the resistance of electrodes cannot be sufficiently reduced due to spatial constraints
Solution Approach 1:
By utilizing the vertical dimension to create raised electrodes, the patent enables multiple electrodes to be accommodated in a limited horizontal area while each electrode achieves sufficient cross-sectional area for low resistance. This three-dimensional configuration allows multi-pattern heating elements to be implemented without compromising electrode resistance.
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 design effectively lowers the heating temperature of the electrode portion in a limited area, preventing hot wire breakdown and allowing for uniform heating across the pattern area, enabling gradual high-temperature heating and multi-pattern configurations.
Implementation Method 1
the electrode portion is configured to have a smaller resistance than the pattern portion, and thus, an unheated unit may be constituted. Therefore, the resistance of the electrode portion may be remarkably small in a limited area, so that an unheated unit may be constituted. the electrode portion may generate heat at 200° C. or less during current flow
Implementation Method 2
the bridge may be formed to be thicker than the thickness of the track, the thickness of the bridge may be formed within a range of 1.3 to 2.0 with respect to the thickness of the track. The bridge may generate heat at 500° C. or less during current flow
Implementation Method 3
As current is supplied through the electrodes, radiant heat is generated in the heater track
Data Source
AI summary
An electric heater includes a substrate; and a plane heating element disposed on one surface of the substrate, in which the plane heating element includes a pattern portion including a start point and an end point; and an electrode portion connected to the start point and the end point of the pattern portion, and a thickness of the electrode portion is thicker than a thickness of the pattern portion.