Cross-Flow Sieve Surface for Dishwasher Water Filtration

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Water-carrying household appliances, such as dishwashers and washing machines, face challenges with sieve systems becoming clogged under high dirt loads, leading to re-contamination due to ineffective filtration.

Innovation Solution

A sieve device with a stationary sieve surface designed to generate cross currents, featuring elevations and depressions to concentrate dirt particles, allowing for backwashing to maintain functionality and prevent clogging, while maintaining a minimal passage cross-section for water flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional sieve system is used to filter washing water, then filtration is effective under normal conditions, but the sieve becomes clogged under high dirt loads and loses effectiveness

Engineering Contradiction:
Improvefiltration effectivenessVSAvoidclogging
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sieve surface is designed with locally differentiated properties through elevations and depressions. The depressions serve as particle collection zones while the elevations maintain open flow paths. This local quality differentiation allows the sieve to handle high dirt loads without clogging, as particles are concentrated in specific areas rather than blocking the entire sieve surface.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sieve surface is segmented into functional zones through the elevation-depression pattern. This segmentation creates distinct particle collection areas (depressions) and flow maintenance areas (elevations), allowing the system to continue filtering effectively even when particles accumulate in specific segments.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the sieve surface area is increased to handle more particles, then filtration capacity improves, but the device complexity and space requirements increase

Engineering Contradiction:
Improvefiltration capacityVSAvoidsieve structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Instead of increasing sieve area in two dimensions, the invention utilizes the third dimension by creating elevations and depressions on the sieve surface. This vertical dimensionality allows particle collection without requiring additional horizontal space, maintaining filtration capacity while avoiding increased device complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The elevations and depressions are integrated into the existing sieve structure rather than adding separate components. The particle collection function is nested within the sieve surface itself through the elevation-depression pattern, avoiding additional device complexity while maintaining high filtration capacity.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 ensures reliable filtration even with high dirt loads, prevents re-contamination, and allows for maintenance-free operation by effectively concentrating and removing dirt particles during backwashing, maintaining the sieve system's effectiveness.

Implementation Method 1

the sieve surface is designed to generate cross currents directed transversely to the flow direction of the sieve surface, so that the cross flow causes retained particles to collect in selected areas

Methodology Applied
Scientific EffectCross flow: Turbulence

Implementation Method 2

The sieve system can be cleaned with a backwashing device, in which the rinsing liquor flows through the sieve system in countercurrent to the direction of flow

Methodology Applied
Scientific EffectBackwashing: Fluid Spray

Implementation Method 3

Due to centrifugal force, dirt particles that adhere to the inside are pushed down into a dirt trap chamber until they are removed during an emptying process

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2217755B1Water-bearing domestic appliance
Publication Date: 2013.06.12 BSH HAUSGERATE GMBH
  • EP2217755B1 patent drawingFigure 1~2

AI summary

The present invention relates to a water-bearing domestic appliance, in particular a dishwasher or washing machine, at least having a hydraulic circuit and a stationary screening apparatus (10) which has a screening face (12), which is arranged in the hydraulic circuit, for filtering recirculated washing water. The invention is characterized in that the screening face (12) is formed so as to generate transverse flows which are directed transverse to the passage-flow direction (D) of the screening face (12).