Microwave Oven Heater Assembly With Airflow-Cooled Reflection Plate
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Solution Overview
Problem
Conventional microwave oven heater assemblies face issues with incomplete insulation of ceramic heaters, leading to potential sparks due to overheating, which complicates the configuration and reduces reliability, necessitating additional cooling fans for heat dissipation.
Innovation Solution
A heater assembly design for a microwave oven that includes a ceramic heater and a halogen heater with a reflection plate having open portions for the ceramic heater to prevent overheating contact and uses a cooling fan-generated airflow through a heater duct for indirect heat dissipation, eliminating the need for additional heat dissipation components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If insulators are fixed to ceramic heater during manufacturing, then heater assembly is complete, but insulation may be incomplete leading to overheating and sparks
Solution Approach 1:
The patent applies beforehand cushioning by providing a cooling fan that generates airflow to cool the ceramic heater before overheating can occur. The cooling fan is positioned to direct airflow toward the ceramic heater, preventing temperature buildup that could cause insulation failure or sparks. This proactive cooling measure compensates for potential insulation deficiencies.
Solution Approach 2:
The patent introduces air as an intermediary cooling medium between the ceramic heater and its surroundings. The cooling fan moves air through a passage formed by the reflection plate and heater cover, allowing heat to be dissipated from the ceramic heater surface without direct contact with insulating materials, thus preventing overheating-related failures.
2Reliability
If additional cooling fan is added for ceramic heater cooling, then overheating prevention is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by making the reflection plate serve multiple functions: it reflects heat from the halogen heater toward the cooking chamber, forms a cooling passage for the ceramic heater, and structurally supports the heater assembly. This multi-functionality eliminates the need for separate cooling components, maintaining reliability while avoiding increased complexity.
Solution Approach 2:
The patent merges the heat reflection function and cooling passage function into a single integrated reflection plate structure. The reflection plate is formed with a through-passage that simultaneously allows heat reflection and provides a cooling airflow path, combining what would traditionally be separate components into one unified structure.
3Power
If reflection plate is made solid for heat reflection, then heat reflection efficiency is improved, but heat dissipation from ceramic heater is reduced
Solution Approach 1:
The patent applies local quality by creating different functional zones on the reflection plate: one region reflects heat from the halogen heater toward the cooking chamber, while another region forms a through-passage for cooling airflow. This localized differentiation allows the same component to optimize both heat reflection and heat dissipation in different areas.
Solution Approach 2:
The reflection plate is segmented into functional regions: a solid portion for heat reflection and a through-passage portion for cooling airflow. This segmentation allows the plate to simultaneously perform heat reflection and heat dissipation functions without compromising either performance.
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 prevents overheating damage to the ceramic heater, improves product reliability, and simplifies the configuration by using airflow for heat dissipation, reducing production costs and maintaining heating performance.
Implementation Method 1
The cooling fan assembly 17 generates airflow for cooling the magnetron 18 and the high voltage transformer 19
Implementation Method 2
The ceramic and halogen heaters 21 and 22 substantially generate heat used for heating food in the cooking chamber 11
Implementation Method 3
The reflection plate 24 serves to reflect the heat of the ceramic and halogen heaters 21 and 22 to the cooking chamber 11, i.e., downwardly
Implementation Method 4
The porous portion 13A is a portion through which the heat from a ceramic heater 21 and a halogen heater 22 is transferred to the cooking chamber 11
Data Source
AI summary
A heater assembly for a microwave oven is provided. The heater assembly includes a ceramic heater and a halogen heater that provides heat used to cook food in a cooking chamber provided in a cavity assembly; a heater supporter fixed to a side of the cavity assembly, with the ceramic and halogen heaters fixed to the heater supporter; and a reflection plate provided above the ceramic and halogen heaters to reflect heat of the ceramic and halogen heaters to the cooking chamber, wherein a portion of the reflection plate corresponding to the ceramic heater is open in its longitudinal direction. With this structure, contact between a heating wire of the ceramic heater and the reflection plate is prevented and the heat dissipation of the ceramic and halogen heaters is obtained by means of airflow that is generated by a cooling fan assembly to cool electric parts.