Dishwasher, in particular household dishwasher

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Solution Overview

Problem

In dishwashers, the fine screen filter cake buildup reduces wash water permeability, necessitating frequent manual cleaning, which is inconvenient and can lead to inadequate washing results if not performed.

Innovation Solution

An axial circulating pump with a reversible direction is used, allowing for backwashing to break up and detach the filter cake, reducing the need for manual cleaning by routing the washing liquor flow through a second suction line, which connects directly to the collection pot, enabling automated filter cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a fine screen is used to filter wash water, then washing quality is improved, but the filter cake buildup reduces permeability and requires frequent manual cleaning

Engineering Contradiction:
Improvewashing qualityVSAvoidmanual cleaning frequency
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent applies backwashing by reversing the flow direction through the fine screen. Instead of only filtering water from inside to outside, the system periodically reverses the flow to flush accumulated filter cake from the screen surface, automatically cleaning it without user intervention.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The system performs self-cleaning of the fine screen through automated backwashing. The circulating pump reverses its rotation to create reverse flow that detaches and removes filter cake, eliminating the need for manual cleaning by the user while maintaining filtering performance.

Inventive Principle:
Principle #25Self-service

2Device complexity

If a radial pump is used for circulating wash water, then the pump structure is simple, but the pump delivery direction cannot be reversed to enable backwashing

Engineering Contradiction:
Improvepump structureVSAvoidpump delivery direction
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent employs an axial pump whose impeller rotation direction can be dynamically reversed. This dynamic capability allows the pump to switch between normal circulation mode and backwashing mode, adapting the delivery direction to different operational requirements without changing the pump structure.

Inventive Principle:
Principle #15Dynamics

3Reliability

If manual cleaning of the fine screen is performed frequently, then filter permeability is maintained, but user convenience is reduced and water consumption increases

Engineering Contradiction:
Improvefilter permeabilityVSAvoidwater consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The system implements periodic backwashing instead of continuous or frequent manual cleaning. The circulating pump reverses its rotation at scheduled intervals to flush the fine screen, maintaining filter permeability through automated periodic action rather than continuous user intervention.

Inventive Principle:
Principle #19Periodic action

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

This configuration simplifies the handling of the screening device, minimizes manual filter cleaning, and maintains effective wash performance by automatically removing filter cake, reducing water consumption and complexity compared to prior art systems.

Implementation Method 1

The great advantage of an axial pump compared to a radial pump is that by reversing the direction of rotation of the impeller, it is possible to change the pump delivery direction.

Methodology Applied
Scientific EffectImpeller rotation reversal: Impeller

Implementation Method 2

By means of an axial pump, it is therefore possible, by changing the direction of rotation of the impeller, to either drain rinsing liquid out of the collecting pot or introduce it into the collecting pot.

Methodology Applied
Scientific EffectFluid flow detachment: Fluid Spray

Data Source

PatentEP3545813B1Dishwasher, in particular household dishwasher
Publication Date: 2022.08.24 MIELE & CO KG
  • EP3545813B1 patent drawingFigure 1
  • EP3545813B1 patent drawingFigure 2
  • EP3545813B1 patent drawingFigure 3

AI summary

The invention relates to a dishwasher, in particular a household dishwasher, with a washing container (3) providing a washing chamber (4) which serves to hold items to be cleaned, a collection pot (5) into which the washing container (3) flows, and a circulation pump (9) which is fluidly connected to the collection pot (5) by means of a suction line (10), wherein the circulation pump (9) is an axial pump, and a second suction line (19) is provided by means of which the circulation pump (9) is fluidly connected to the collection pot (5).