Dishwasher Treatment Container Assembly to Prevent Crevice Corrosion
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Solution Overview
Problem
Existing water-carrying household appliances, such as dishwashers, face challenges with crevice corrosion when connecting components made of different materials like chromium steel and chromium-nickel steel, particularly due to the risk of moisture penetration and capillary effects in the connection areas.
Innovation Solution
A connection technology is implemented where the mechanical connection between components is made in a moisture-protected section, and a sealing element is strategically placed on the interior side of the washing compartment to prevent capillary gaps, using methods like welding, adhesive, folding, or clamping, ensuring the sealing element remains intact and effectively seals the gap between components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If components are made of different materials (chromium steel and chromium-nickel steel), then manufacturing costs are reduced, but crevice corrosion occurs in connection areas
Solution Approach 1:
The treatment container is divided into multiple components made of different materials (chromium steel and chromium-nickel steel), allowing cost reduction by using simpler chromium steel for non-critical parts while maintaining chromium-nickel steel for corrosion-prone areas. The components are mechanically connected via folds rather than welded, preventing crevice corrosion at connection points.
Solution Approach 2:
A sealing element made of elastomeric material is introduced as an intermediary between the chromium steel container roof and chromium-nickel steel side walls. This sealing element prevents moisture penetration and capillary effects at the mechanical connection, eliminating the crevice corrosion risk while allowing the use of different materials.
2Strength
If components are connected via welding, then mechanical strength is ensured, but crevice corrosion occurs in the connection area
Solution Approach 1:
The welding process is replaced with a mechanical connection system consisting of folds and sealing elements. The container roof and side walls are mechanically connected through folded edges with inserted sealing elements, providing sufficient mechanical strength while eliminating the crevice corrosion risk associated with welded joints.
3Reliability
If a sealing element is inserted via squeezing process, then sealing effect is achieved, but the sealing element may be squeezed off or not rest intimately on component walls
Solution Approach 1:
The sealing element is pre-inserted into the fold before the final assembly step. The fold structure is designed to automatically clamp and secure the sealing element in place during assembly, preventing it from being squeezed off while ensuring intimate contact with the component walls for effective sealing.
Solution Approach 2:
An elastomeric sealing element with flexible properties is used, allowing it to deform and conform to the component surfaces for intimate contact. The flexibility of the elastomeric material enables the sealing element to maintain sealing pressure without being squeezed off by the assembly process.
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 solution effectively prevents crevice corrosion by ensuring a capillary-free design, allowing the use of simpler chromium steel components while maintaining corrosion resistance and a visually appealing, smooth interior surface, even when connecting components with different corrosion resistance properties.
Implementation Method 1
a gap between the edges of the two components, which is exposed to moisture and has a capillary effect, is sealed by means of a sealing element
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a water-conducting household appliance, particularly a dishwasher, comprising a treatment container assembled of at least two components (10, 20) made of different materials. Each component (10, 20) comprises an edge section (11, 21). A mechanical connection (31; 40; 32) of the two components is achieved via said edge section, wherein the mechanical connection is located in a section (51) protected from humidity. The sealing of the mechanical connection by means of a sealing element (30) is located on the side facing the dishwashing interior space (50) of the treatment container such that a gap, exposed to humidity and having a capillary effect, between the components is omitted.