Electrostatic filter unit and extraction hood device with electrostatic filter unit

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Solution Overview

Problem

Existing electrostatic filter units for ventilation devices, such as extractor hoods, have complex structures and a high risk of damage due to wire ionization electrodes, which can break or experience voltage fluctuations, and face challenges with particle contamination and electrical creepage issues.

Innovation Solution

An electrostatic filter unit with a simplified structure featuring needle-shaped ionization electrodes with insulating coatings, housed within a conductive frame, and a plate-shaped counter electrode with openings, minimizing obstruction and promoting higher electric field strength for effective particle charging and filtration while reducing the risk of damage and contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If wire-shaped ionization electrodes are used, then the filter can be compact, but the structure becomes susceptible to damage from wire breakage or voltage arcing

Engineering Contradiction:
Improvefilter compactnessVSAvoidresistance to damage
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent extracts the ionization function from a continuous wire structure and concentrates it at discrete needle-shaped electrode tips. This extraction of the critical ionization function to specific points allows the use of more robust needle structures instead of fragile wires, while maintaining the necessary compact form factor of the filter unit.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the geometric parameters of the ionization electrode from thin wires to needle-shaped structures with specific tip radii (0.1-1mm). This parameter change increases the mechanical strength and damage resistance while maintaining the ionization capability through the concentrated electric field at the needle tips.

Inventive Principle:
Principle #35Parameter changes

2Strength

If plate-shaped deposition electrodes with electrically conductive bridges are used, then the structure provides structural support, but the number of parts and design complexity increases

Engineering Contradiction:
Improvestructural supportVSAvoidnumber of parts
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the structural support function and the electrical connection function into a single ionization electrode frame made of electrically conductive material. This frame provides both mechanical support for the needle-shaped electrodes and electrical connectivity, eliminating the need for separate structural supports and conductive bridges, thereby reducing part count and design complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The ionization electrode frame serves multiple functions simultaneously: it provides structural support for the needle electrodes, acts as an electrical conductor to deliver high voltage, and serves as a mounting structure. This multi-functionality reduces the overall complexity of the filter design by consolidating multiple components into one.

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

3Power

If the ionization electrode tip is positioned in the opening of the counter electrode, then higher electric field strength is achieved for better particle charging, but the risk of voltage arcing increases

Engineering Contradiction:
Improveelectric field strengthVSAvoidvoltage arcing
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by providing insulating coating only on specific portions of the ionization electrode frame and needle electrodes, leaving the tips exposed. This localized insulation approach allows the tips to generate high electric field strength for effective particle charging while the coated portions prevent unwanted voltage arcing and electrical discharge along the electrode surfaces.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The insulating coating acts as an intermediary material between the conductive electrode surfaces and the surrounding environment. It mediates the electrical field distribution, allowing concentrated field strength at the exposed tips for ionization while preventing harmful arcing along the electrode bodies, thus resolving the contradiction between power and harmful effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Device complexity

If wire ionization electrodes are used without insulating coating, then the structure is simple, but electrical creepage and contamination issues arise

Engineering Contradiction:
Improvestructural simplicityVSAvoidelectrical creepage and contamination
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the surface properties of the ionization electrode by applying insulating coating, transforming it from a fully conductive surface to a partially insulated structure with exposed tips. This parameter change eliminates electrical creepage along the electrode surface and prevents contamination buildup, while maintaining relative structural simplicity through selective coating rather than complete redesign.

Inventive Principle:
Principle #35Parameter changes

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 provides a safer, more reliable filtration system with enhanced particle charging efficiency, reduced risk of electrical issues, and improved resistance to water and contamination, maintaining effective filtration performance even under heavy mechanical stress and high particle loads.

Implementation Method 1

the tip being located in the opening of the counter electrode, wherein the ionization electrode and the ionization electrode frame have an insulating coating

Methodology Applied
Scientific EffectCorona discharge: Corona Discharge

Implementation Method 2

the counter electrode has at least one opening and the ionization element comprises an ionization electrode frame made of electrically conductive material and at least one needle-shaped ionization electrode with a tip

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 3

the ionization electrode and the ionization electrode frame have an insulating coating

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 4

at least one needle-shaped ionization electrode with a tip, to which the ionization electrode is attached

Methodology Applied
Scientific EffectElectric field concentration: Electric Field

Data Source

PatentEP3552710B1Electrostatic filter unit and extraction hood device with electrostatic filter unit
Publication Date: 2023.12.27 BSH HAUSGERATE GMBH
  • EP3552710B1 patent drawingFigure 1~3
  • EP3552710B1 patent drawingFigure 4~5
  • EP3552710B1 patent drawingFigure 6~7

AI summary

The present invention relates to an electrostatic filter unit for a ventilation device (5), comprising an ionization unit (2) with at least one ionization element (28) and at least one counter electrode (22), and a separation unit (3). The filter unit (1) is characterized in that the at least one counter electrode (22) has at least one opening (220), and the ionization element (28) comprises at least one needle-shaped ionization electrode (21) with a tip (211), the ionization electrode (21) being perpendicular to the opening (220) of the counter electrode (22), and the tip (211) being located in the opening (220) of the counter electrode (22). The invention further relates to a ventilation device (5) comprising at least one such filter unit.