Dishwasher Filter Openings With Graded Walls for Lower Flow Resistance
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Solution Overview
Problem
Existing dishwasher filter combinations are difficult to manufacture efficiently and can have high flow resistance due to sharp edges and uneven mold contact during the injection molding process, leading to increased production tolerances and flow losses.
Innovation Solution
A filter element with a graded inner wall contour and hexagonal filter openings, where the downstream section expands in the flow direction, reduces flow resistance and allows for easier production by minimizing sharp edges and accommodating mold offsets, enhancing the flow-favorable design and material distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional filter openings with sharp edges are used, then manufacturing is simpler, but flow resistance increases
Solution Approach 1:
The patent applies curvature by replacing sharp-edged filter openings with rounded hexagonal openings. The inner wall contour of each filter opening features rounded transitions instead of sharp edges, creating a more flow-friendly geometry that reduces turbulence and energy loss while maintaining manufacturability through injection molding
2Ease of manufacture
If uniform wall thickness is used in filter openings, then manufacturing is easier, but flow distribution becomes uneven
Solution Approach 1:
The patent implements local quality by varying the wall thickness around the filter openings. The inner wall contour creates regions of different thickness: thinner walls at the upstream side and thicker walls at the downstream side of each opening. This non-uniform distribution optimizes flow characteristics while remaining compatible with injection molding processes
3Loss of energy
If round filter openings are used, then flow resistance is reduced, but manufacturing precision deteriorates due to mold offsets
Solution Approach 1:
The patent employs asymmetry by designing hexagonal filter openings instead of round openings. The hexagonal geometry with specific orientation relative to the mold parting line makes the filter openings less sensitive to mold offsets and positioning tolerances. The asymmetric wall thickness distribution within each hexagonal opening further compensates for manufacturing variations, ensuring consistent flow characteristics
Data Source
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AI summary
The invention relates to a water-bearing household appliance, in particular a dishwasher, with a hydraulic circuit in which washing liquid can be circulated, and a filter device (17) which has a filter element (15) with at least one filter opening (19) for the passage of washing liquid, the The filter opening (19) is delimited by an inner wall (27) surrounding the filter opening (19). According to the invention, a step (39) is formed at least between an upstream and a downstream wall section (43, 45) of the inner wall (27) of the filter opening (19). Additionally or independently of this, the downstream wall section (45) has a cross section that increases in the flow direction of the rinsing liquid.