Filter element for an extractor hood
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Solution Overview
Problem
Existing filter elements in extractor hoods, particularly those made of expanded metal, suffer from high pressure loss and low filtration efficiency due to large openings, leading to increased energy consumption and unit costs, while also being prone to rough edges and material losses.
Innovation Solution
A filter element with multiple layers of molded plastic material, where the openings are fixed in size and finer than those of expanded metal filters, reducing pressure loss and enhancing filtration efficiency by increasing the number and uniformity of small openings, and using plastic profiles to form the layers which can be arranged in various configurations to optimize air permeability and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If expanded metal filter layers with large openings are used, then pressure loss per layer is minimized, but filtration efficiency is low due to large meshes being too wide for finer particles
Solution Approach 1:
The filter element is divided into multiple filter layers (at least two) with different mesh sizes. The first filter layer has larger openings for coarse filtration, while the second filter layer has smaller openings for fine filtration. This segmentation allows each layer to perform its specific function optimally, achieving both low pressure loss (from the first layer) and high filtration efficiency (from the second layer).
Solution Approach 2:
Different regions of the filter element have different properties - the first filter layer is designed with large openings suitable for its position and function, while the second filter layer is designed with small openings suitable for its position and function. Each filter layer is optimally adapted to its local requirements, allowing the first layer to minimize pressure loss and the second layer to capture fine particles effectively.
2Manufacturing precision
If more layers are used to increase filter efficiency, then filtration performance improves, but unit costs and weight per filter increase significantly
Solution Approach 1:
The filter is segmented into exactly two functional layers with different mesh sizes, avoiding the need for multiple identical layers. This segmentation achieves high filtration efficiency through the complementary functions of the two layers while keeping the total number of layers minimal, thus reducing weight and cost compared to using many layers of uniform design.
Solution Approach 2:
The filter element uses a composite structure with two different filter layers made of plastic material with different opening sizes. This composite approach combines the advantages of both large-opening and small-opening filters in a single element, achieving high filtration efficiency without the need for multiple separate filter components, thereby reducing overall weight and cost.
3Manufacturing precision
If the number of filter layers is increased to achieve higher filter efficiency, then separation performance improves, but the filter element requires more installation space
Solution Approach 1:
The filter is segmented into two compact layers with different functions, allowing high filtration efficiency to be achieved in a minimal space. The first layer handles coarse particles and the second layer handles fine particles, eliminating the need for additional layers and reducing the overall installation space requirement while maintaining high separation performance.
4Area of moving object
If expanded metal is used with scored and stretched manufacturing process, then large openings are achieved, but edges become extremely rough causing high pressure drop
Solution Approach 1:
The patent uses plastic material instead of expanded metal, accepting that plastic filters may need replacement but gaining smooth edges and low pressure drop. The plastic filter layers are molded with smooth surfaces that do not create the turbulence and pressure drop associated with rough expanded metal edges, energy efficiency is improved even if the filter has a shorter service life.
Solution Approach 2:
The manufacturing process is changed from mechanical scoring and stretching of metal to molding of plastic material. This parameter change in the manufacturing process allows for smooth edges and surfaces to be achieved, eliminating the rough edges problem of expanded metal while maintaining large openings, thus reducing pressure drop.
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 achieves a 25-50% higher filter efficiency with 10% lower pressure loss, reduces turbulence, and increases the filter's resistance to corrosion and material costs, allowing for more effective separation of fat particles and other contaminants with improved durability and reduced installation space.
Implementation Method 1
the separation of the fat particles from the vapours or cooking fumes takes place, for example, by inertial separation
Implementation Method 2
reduces turbulence
Data Source
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AI summary
The invention relates to a filter element (2) for an extractor hood (1), which has at least one filter layer (20), characterized in that at least one filter layer (20) consists of a plastic material (201) and the filter layer (20) has openings (202 ) whose size is fixed.