Variable-Area Liquid Filtration for Clog-Resistant Appliances

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Solution Overview

Problem

Existing liquid filtration systems in water-using household appliances face premature clogging issues, leading to increased hydraulic resistance and reduced flow rates, which can be exacerbated by the accumulation of particles on the filter surface.

Innovation Solution

A system with a movable element that varies the filter surface area by changing its position and size, controlled by an actuator or servo motor, to maintain a constant hydraulic resistance and flow rate by periodically expanding the available filter surface as it becomes clogged.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dead-end filtration is used to filter particles from liquid, then filtration effectiveness is improved, but hydraulic resistance increases rapidly leading to premature clogging

Engineering Contradiction:
Improvefiltration effectivenessVSAvoidflow rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The filter surface area is made dynamic through a movable filter element that can change its position and effective surface area. The filter element is connected to a drive mechanism that periodically moves it along its longitudinal axis, allowing the system to adapt the filter surface area to operating conditions and prevent premature clogging by redistributing the filtration load.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of filter surface area dynamically during operation. By moving the filter element along its longitudinal axis, the effective filter surface area available to the liquid flow is varied, which changes the hydraulic resistance characteristics and prevents the rapid clogging that occurs with static filter surfaces.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If filter surface area is increased to maintain flow rate, then productivity is improved, but device complexity increases due to movable elements and actuators

Engineering Contradiction:
Improveflow rateVSAvoidsystem structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The filter element is segmented along its longitudinal axis, with different sections that can be selectively engaged or disengaged from the liquid flow path. This segmentation allows the effective filter surface area to be adjusted in discrete steps by moving the filter element to different positions, providing variable filtration capacity without requiring a completely complex adjustable mechanism.

Inventive Principle:
Principle #1Segmentation

3Reliability

If filter element is made movable to vary filter surface, then hydraulic resistance stability is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvehydraulic resistance stabilityVSAvoidfilter element assembly
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The movable filter element serves multiple functions: it provides the filtration surface, acts as a movable component that varies the effective filter area, and works with the drive mechanism to automatically adjust to clogging conditions. This multi-functionality reduces the need for separate adjustment mechanisms and simplifies the overall manufacturing process despite the added mobility feature.

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

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 system ensures a consistent hydraulic resistance and flow rate by dynamically adjusting the filter surface, reducing the need for frequent filter cleaning and improving energy efficiency by allowing smaller pumps to maintain optimal performance.

Implementation Method 1

at least a part of the housing (2) is designed as a filter element (3), so that the liquid can be discharged from the at least one space (5) via a filter surface of the filter element (3), wherein the filter element (3) is designed to filter particles from the liquid

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

the filter surface of the filter element (3) is variable by the at least one movable element (10, 11), so that the filter surface of the filter element (3) available to the liquid can be varied by the at least one movable element (10, 11), in particular with regard to its position and/or size

Methodology Applied
Scientific EffectMechanical displacement: Displacement

Data Source

PatentEP3915662B1System for filtering a liquid, water-conducting domestic appliance with the system and method for filtering a liquid
Publication Date: 2025.10.01 BOSCH SIEMENS HAUSGERATE GMBH
  • EP3915662B1 patent drawingFigure 1
  • EP3915662B1 patent drawingFigure 2
  • EP3915662B1 patent drawingFigure 3

AI summary

A system (1) for filtering a liquid, particularly for a water-bearing household appliance, is provided. The system (1) comprises a housing (2) which has at least one movable element (10) inside it, which together with the housing (2) defines at least one substantially fluid-tight space (5), and a liquid supply (4) configured to supply a liquid to the at least one space (5). At least a part of the housing (2) is configured as a filter element (3) such that the liquid can be discharged from the at least one space (5) via a filter surface of the filter element (3). The filter element (3) is configured to filter particles (9) from the liquid.The filter area of ​​the filter element (3) is variable by means of the at least one movable element (10), so that the filter area of ​​the filter element (3) available to the liquid can be changed by the at least one movable element (10), in particular with regard to its position and/or size. Furthermore, a water-bearing household appliance with the system (1) and a method for filtering a liquid are provided.