Domestic appliance with filter unit, method for determining the saturation of a filter unit of a domestic appliance

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Solution Overview

Problem

Current filter units in air-carrying household appliances, such as extractor hoods, lack a reliable method to determine saturation, leading to inaccurate cleaning intervals and potential filter failure due to excessive contamination, which is not accounted for by existing methods that rely on operating time rather than actual usage patterns.

Innovation Solution

Incorporating a capacitive measuring unit within the filter unit to measure capacitance between electrodes, which changes with impurity accumulation, allowing for precise determination of filter saturation and timely notification for cleaning, thereby optimizing cleaning intervals based on user-specific cooking behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If filter saturation is determined by operating time, then cleaning intervals can be estimated, but the determination is imprecise and does not reflect actual usage conditions

Engineering Contradiction:
Improvefilter saturation detection precisionVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical/time-based saturation estimation with an electrical measurement system. A capacitive measuring unit measures the capacitance between the precipitation electrode and counter electrode, which changes as impurities accumulate on the electrodes. This electrical measurement provides precise real-time saturation detection without relying on operating time estimates.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The filter unit itself provides the measurement capability through its inherent electrode structure. The precipitation electrode and counter electrode, already present for electrostatic filtration, are used as capacitive sensors to detect saturation. This eliminates the need for separate external sensors and integrates the measurement function into the existing filter structure.

Inventive Principle:
Principle #25Self-service

2Reliability

If a capacitive measuring unit is added to measure capacitance between electrodes, then filter saturation can be precisely detected, but the device complexity increases

Engineering Contradiction:
Improvefilter saturation detection reliabilityVSAvoidfilter unit structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electrode structure serves dual functions: it performs the primary electrostatic filtration function while simultaneously acting as a capacitive sensor for saturation detection. The precipitation electrode and counter electrode are used both for charge separation and for capacitance measurement, making the system multi-functional and reducing the need for additional dedicated components.

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

Solution Approach 2:

The capacitance measurement serves as an intermediary parameter that indirectly indicates filter saturation. Instead of directly measuring impurity accumulation, the system measures the change in electrical capacitance caused by impurity accumulation on the electrodes, providing a reliable proxy measurement that is easier to implement.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If cleaning intervals are extended based on operating time in single-person households, then maintenance frequency is reduced, but filter efficiency may be compromised due to not accounting for actual cooking intensity

Engineering Contradiction:
Improvefilter cleaning efficiencyVSAvoidfilter performance reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The capacitive measuring unit provides continuous feedback on the actual saturation level of the filter. This feedback allows the system to dynamically determine when cleaning is actually needed based on real conditions rather than fixed time intervals. The measurement results can trigger cleaning notifications only when saturation reaches a threshold, optimizing cleaning timing based on actual usage intensity.

Inventive Principle:
Principle #23Feedback

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

Enables reliable detection of filter saturation, preventing filter failure by adjusting cleaning intervals according to actual usage, ensuring optimal filter efficiency and extending the lifespan of the filter unit.

Implementation Method 1

it has at least one capacitive measuring unit for measuring the capacitance between the precipitation electrode and the counter electrode

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

an ionization unit and a separation unit in which positive and negative electrodes are arranged alternately

Methodology Applied
Scientific EffectIonization: Ionisation

Implementation Method 3

a separation unit with at least one precipitation electrode and at least one counter electrode, in which the precipitation electrode and the counter electrode are arranged alternately and at a distance from each other

Methodology Applied
Scientific EffectElectrostatic precipitation: Electrostatic Deposition

Data Source

PatentEP3409371B1Domestic appliance with filter unit, method for determining the saturation of a filter unit of a domestic appliance
Publication Date: 2020.02.26 BSH HAUSGERATE GMBH
  • EP3409371B1 patent drawingFigure 1
  • EP3409371B1 patent drawingFigure 2~3
  • EP3409371B1 patent drawingFigure 4~5

AI summary

The invention relates to a household appliance with at least one filter unit, which has an ionization unit (22) and a separation unit (21) with at least one collecting electrode (211) and at least one counter-electrode (210), and in which the collecting electrode (211) and the counter-electrode (210 ) are arranged alternately and at a distance (d) from one another. The household appliance (1) is characterized in that the household appliance (1) has at least one capacitive measuring unit (3) for measuring the capacitance between the collecting electrode (211) and the counter-electrode (210). The invention also relates to a method for determining the saturation of a filter unit (2) of such a household appliance (1). The method is characterized in that the method comprises the step of a reference measurement and at least one operational measurement of the capacitance between the electrodes (210, 211) of the separating unit (21).