Extractor Hood With Backward-Curved Fan for Quiet Compact Venting
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Solution Overview
Problem
Existing extractor hoods with forward-curved radial fans require significant space due to logarithmically expanding worm housings, limiting their ability to effectively extract cooking vapors while also producing noise.
Innovation Solution
The use of a backward-curved fan wheel within the extractor hood reduces space requirements and enhances vapor extraction efficiency, accompanied by noise reduction through a labyrinthine air duct and integrated circulating air filters that dampen sound and filter air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a forward-curved radial fan with worm housing is used, then the fan can build up working pressure effectively, but the extractor hood requires a relatively large amount of space
Solution Approach 1:
The patent changes the fundamental parameter of fan blade curvature from forward-curved to backward-curved. This parameter change fundamentally alters the fan's operational characteristics, allowing it to achieve effective vapor extraction without requiring the space-consuming worm housing that forward-curved fans need for pressure buildup.
2Productivity
If a forward-curved radial fan is used, then the fan can generate air flow, but noise emissions during operation are increased
Solution Approach 1:
The patent changes the fan blade curvature parameter to backward-curved, which fundamentally alters the noise generation mechanism. Backward-curved fans produce significantly lower noise emissions because they avoid the blade rotation sound characteristic of forward-curved fans, while maintaining effective air flow generation for vapor extraction.
3Volume of stationary object
If a backward-curved fan wheel is used, then space requirements are reduced and vapor extraction efficiency is enhanced, but the fan requires optimized airflow guidance to function effectively
Solution Approach 1:
The patent merges the air duct function directly into the extractor housing structure, creating an integrated airflow guidance system. This integration eliminates the need for separate, complex airflow guidance components while ensuring optimal airflow patterns for the backward-curved fan wheel, thereby reducing overall device complexity.
Solution Approach 2:
The integrated air duct serves as an intermediary structure that guides airflow from the cooking surface to the fan inlet. This mediator ensures smooth, optimized airflow patterns that maximize the efficiency of the backward-curved fan wheel while maintaining a compact overall design.
4Object-generated harmful factors
If the fan wheel size is increased to reduce noise emissions, then lower fan wheel speeds can be used, but the extractor housing must accommodate the larger fan
Solution Approach 1:
The patent changes the fan blade curvature parameter to backward-curved, which allows the fan to operate efficiently at lower speeds with larger wheel diameters. This parameter change enables noise reduction through reduced rotational speed while the compact housing design accommodates the larger fan wheel through optimized spatial arrangement.
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 extractor hood achieves effective vapor extraction with reduced power consumption and noise emissions, utilizing a backward-curved fan wheel and integrated noise-dampening features, resulting in a more compact and quieter design.
Implementation Method 1
the fan having a radial fan wheel with backward-curved blades
Implementation Method 2
the air flow in the air duct being guided from the underside of the extractor housing towards the top of the extractor housing
Implementation Method 3
integrated circulating air filters that dampen sound and filter air
Data Source
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AI summary
The invention relates to a cooker hood (1) for extracting cooking fumes (2) above a hob (3) by means of an airflow (4), with a hood housing (5) which has at least one air intake opening (6) and at least one air outlet (7) for the airflow (4), and at least one fan (8) arranged in the hood housing (5) for generating the airflow (4), wherein the fan (8) is a radial fan having a backward-curved impeller (9).