Dishwasher Reverse-Flow Filtration for Self-Cleaning Impurity Removal
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Solution Overview
Problem
Conventional dishwasher filter arrangements require large-area filters that clog easily, reducing the cleaning effectiveness and necessitating manual cleaning, while existing self-cleaning filters are inefficient and can compromise wash cycles if heavily loaded with impurities.
Innovation Solution
A dishwasher design with a self-cleaning filter that reverses the direction of flow to ensure continuous filtration and cleaning, eliminating the need for manual filter maintenance and optimizing power consumption and cleaning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large-area filters are used in conventional filter arrangements, then the flow to the pump is guaranteed and impurities are filtered effectively, but the filters clog easily and require manual cleaning
Solution Approach 1:
The patent applies reverse flow to clean the filter element. During the drain phase, the pump reverses rotation to create reverse flow through the filter element, washing accumulated impurities from the filter surface back into the wash compartment. This inversion of flow direction enables self-cleaning without manual intervention.
Solution Approach 2:
The filter element cleans itself through the reverse flow mechanism. The system uses its own pump and circulating water to automatically wash the filter element during the drain phase, eliminating the need for manual cleaning by the user.
2Reliability
If multiple filter elements (coarse, fine, micro filters) are arranged in parallel, then impurities are filtered effectively, but the device complexity increases and maintenance becomes more difficult
Solution Approach 1:
The patent extracts and eliminates the complex multi-stage filter arrangement (coarse, fine, and micro filters in parallel) from the pump well. Instead, a single filter element is positioned in the water circuit where it is automatically cleaned by reverse flow, simplifying the overall filter system while maintaining effective impurity removal.
Solution Approach 2:
The single filter element performs multiple functions: it filters impurities during the wash phase and is cleaned during the drain phase through reverse flow. This multi-functionality replaces the need for multiple specialized filter elements.
3Reliability
If coarse impurities are held in the pump well, then they are retained for filtration, but they provide an attack surface for cleaning agents reducing cleaning effectiveness
Solution Approach 1:
The filter element is continuously cleaned during the drain phase through reverse flow, preventing accumulation of impurities that would create attack surfaces. This continuous cleaning action ensures the filter surface remains clean and does not interfere with cleaning agent effectiveness.
Solution Approach 2:
The reverse flow that could be seen as disrupting filtration is actually beneficial, as it continuously cleans the filter element and prevents impurity accumulation. The same water circulation system that filters impurities also cleans the filter itself.
4Ease of operation
If self-cleaning filters are implemented, then manual cleaning is eliminated, but the cleaning effectiveness may be reduced if the filter is heavily loaded with impurities
Solution Approach 1:
The reverse flow cleaning occurs periodically during each drain phase of the wash cycle. This regular periodic cleaning prevents excessive impurity accumulation on the filter element, ensuring it remains effective throughout the wash phase while providing automatic cleaning without manual intervention.
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 self-cleaning filter arrangement ensures reliable and effective impurity removal without manual intervention, maintaining high cleaning performance and reducing energy consumption by preventing clogging and maintaining effective wash cycles.
Implementation Method 1
the washing liquor being conveyed through a filter element during circulation in order to filter impurities
Implementation Method 2
a device for reversing the direction of flow is provided which enables circulation of the washing liquor in a second direction, opposite to the first direction, so as to flow through and remove impurities from a first filter
Data Source
AI summary
A dishwasher, in particular a domestic dishwasher, having at least one substantially closed water circuit in which washing liquor is recirculated in a first direction in accordance with a program control unit, with the washing liquor being conveyed through a filter element during recirculation in order to filter impurities. Provision is made of a device for reversing the direction of flow, and this allows recirculation of the washing liquor in a second direction, which runs counter to the first direction, in order to flow through and eliminate impurities from a first screen, with the first screen being arranged in the water circuit in such a way that liquid forcibly flows through the first screen during recirculation of the washing liquor both in the first and in the second direction.