Dual-Coil Electric Heating Element With Inner Coil Temperature Control
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Solution Overview
Problem
Stovetop electric heating elements are prone to overheating, posing fire hazards and requiring manufacturers to conform to the UL 858 Standard for Household Electric Ranges. There is a need for automatic temperature control to prevent overheating and for retrofitting existing electric stoves with improved heating elements that meet the UL 858 standard without requiring adaptors.
Innovation Solution
The electric heating element comprises an electrically resistive inner and outer heating element, temperature sensors along the cold leg of the inner heating element, and a controller that adjusts the electrical current to the inner heating element while maintaining maximum current to the outer heating element. This configuration allows for precise temperature control and safe operation without the need for adaptors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single heating element is used, then the device complexity is low, but the temperature control precision is insufficient leading to overheating hazards
Solution Approach 1:
The heating element is divided into two separate coils: an inner heating element and an outer heating element. This segmentation allows independent temperature control of each zone, enabling precise temperature regulation and preventing overheating while maintaining a manageable structural complexity through modular design.
Solution Approach 2:
Different regions of the heating surface are assigned different heating elements with different control characteristics. The inner heating element provides focused high-heat output for rapid heating, while the outer heating element provides distributed heat for temperature maintenance, creating local quality variations that improve overall temperature control safety.
2Adaptability or versatility
If an adaptor is added to enable mounting, then the adaptability to existing stoves is improved, but the ease of installation deteriorates due to additional components
Solution Approach 1:
The heating element assembly is designed with a universal mounting interface that directly fits standard stove receptacles. The outer heating element serves dual purposes: as a heating source and as a structural mounting frame, eliminating the need for separate adaptors while maintaining compatibility with existing stove configurations.
Solution Approach 2:
The mounting structure is merged with the outer heating element itself. The outer coil serves both as a functional heating element and as the structural component that interfaces with the stove receptacle, combining multiple functions into a single integrated unit that simplifies installation.
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 solution effectively regulates heat to prevent overheating, ensuring safe cooking and compliance with the UL 858 standard. The adaptor-free design facilitates easy retrofitting of existing electric stoves, enhancing safety and performance.
Implementation Method 1
Electric heating elements convert electrical energy to heat energy
Implementation Method 2
one or more temperature sensors positioned along a cold leg of the inner heating element
Data Source
AI summary
An embodiment of an electric heating element is disclosed, including an electrically resistive inner heating element, an electrically resistive outer heating element, and a thermostat positioned underneath a centrally-positioned medallion and along a cold leg of the inner heating element. The thermostat is configured to selectively allow electrical current to be delivered to the inner heating element while maximum electrical current, for example, continues to be provided to the outer heating element. The thermostat cycles the electrical current on and off when detecting maximum and minimum desired temperatures radiated from the electric heating element. The inner heating element has a pair of cold legs that extend parallel to a pair of cold legs of the outer heating element, some or all of which may be supported by a terminal bracket.