Microwave Oven Cooling Assembly With Single-Fan Branched Airflow

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Solution Overview

Problem

Modern microwave ovens with both microwave heating and pyrolytic cleaning functions require two cooling fans, which are complex and expensive due to the need for separate cooling systems for the magnetron and the oven door/housing.

Innovation Solution

A microwave oven design incorporating a single cooling fan assembly with a branching air duct system that separately cools the inverter and magnetron, integrating ventilation of the oven cavity and door, using a double-inlet centrifugal fan to optimize airflow efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If two cooling fans are used (one for magnetron, one for oven door/housing), then cooling effectiveness is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecooling effectivenessVSAvoidnumber of cooling fans
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent combines the cooling functions for the magnetron and the oven door/housing into a single cooling fan system. One cooling fan is used to cool both the magnetron and the oven door/housing simultaneously, reducing the number of fans from two to one, thereby reducing device complexity and cost while maintaining cooling effectiveness through proper airflow channel design

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single cooling fan is designed to perform multiple cooling functions: it cools the magnetron, the oven door, and the housing through different airflow channels. This multi-functional design allows one fan to replace what would traditionally require two separate fans, addressing the contradiction between cooling effectiveness and device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If a single cooling fan is used for both magnetron and oven door, then device complexity is reduced, but airflow distribution and cooling efficiency may deteriorate

Engineering Contradiction:
Improvenumber of cooling fansVSAvoidcooling efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent segments the airflow into separate channels: a first airflow channel for cooling the magnetron and a second airflow channel for cooling the oven door and housing. This segmentation allows a single fan to provide dedicated airflow paths to different components, maintaining cooling efficiency while reducing the number of fans required

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediate carrier element that holds the cooling fan and facilitates airflow distribution. This intermediary structure enables the single fan to efficiently distribute cooled air to multiple components (magnetron, oven door, housing) through properly designed channels, preventing cooling efficiency deterioration

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enhances cooling efficiency and reduces complexity and cost by utilizing a single fan to effectively cool the inverter, magnetron, and oven door, while maintaining airflow velocity and directionality for improved component cooling.

Implementation Method 1

a cooling fan assembly (14) comprising only one fan (20) configured to ventilate the oven cavity (4) and/or an oven door (16) and to force cooling air through the inverter (8) and the magnetron (10)

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

to force cooling air through the inverter (8) and the magnetron (10)

Methodology Applied
Scientific EffectConvection Cooling: Convection

Data Source

PatentEP4444040B1Microwave oven
Publication Date: 2026.02.25 ELECTROLUX APPLIANCES
  • EP4444040B1 patent drawingFigure 1
  • EP4444040B1 patent drawingFigure 2
  • EP4444040B1 patent drawingFigure 3

AI summary

A microwave oven (1) is described. That microwave oven (1) comprises a cavity casing (2) defining an oven cavity (4) for treating food, the cavity casing (2) comprising a frontal opening (5) that can be closed by a door (16), electrical components (6) comprising at least an inverter (8) and a magnetron (10), an oven housing (12) enclosing the cavity casing (2) and a component chamber (7) above the oven cavity (4) wherein the electrical components (6) are aligned, and a cooling fan assembly (14). The cooling fan assembly (14) comprises only one fan (20) configured to ventilate the oven cavity (4) and/or an oven door (16) and to force cooling air through the inverter (8) and the magnetron (10). Further, the cooling fan assembly (14) comprises an air duct (22) that branches from a main channel (24) connected to the fan (20) into two air duct branches (26, 28), a first one of such air duct branches (26) being in fluid connection with the inverter (8) and a second one of such air duct branches (28) being in fluid connection with the magnetron (10).