Rotating Dishwasher Filter With Backflow Protection at the Inlet
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Solution Overview
Problem
Dishwashers face challenges in effectively filtering out foreign objects and soil particles from the recirculating wash fluid, leading to potential re-deposition on utensils and reduced machine performance over time.
Innovation Solution
A dishwashing machine with a liquid recirculation system and a rotary filter assembly that includes a rotating filter with artificial boundaries and flow diverters, which creates a backflow zone to prevent foreign objects from entering the recirculation flow path and efficiently separates soil particles from the wash fluid through centrifugal force and pressure gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotating filter is used to filter recirculating wash fluid, then filtration efficiency is improved, but foreign objects may still enter the inlet opening along the recirculation flow path
Solution Approach 1:
The artificial boundary creates a backflow zone that generates counter-flowing liquid movement before the inlet opening, which opposes and retards the entry of foreign objects along the recirculation flow path. This preliminary counter-action prevents harmful objects from reaching the filter inlet.
Solution Approach 2:
The artificial boundary acts as an intermediary structure between the recirculation flow path and the inlet opening. It creates a backflow zone that mediates the flow, allowing filtered liquid to pass through while retarding foreign objects from entering the inlet.
2Device complexity
If the filter is stationary, then the structure is simpler, but soil particles can re-deposit on the filter surface reducing performance over time
Solution Approach 1:
The filter is made rotatable about its longitudinal axis, transforming it from a stationary to a dynamic component. This rotation prevents soil particles from re-depositing on the filter surface by continuously changing the filter surface orientation relative to the incoming flow, maintaining filtration performance over time.
Solution Approach 2:
The rotating filter periodically presents different surface areas to the incoming wash fluid. This periodic action prevents continuous accumulation of soil particles on any single area of the filter surface, thereby maintaining filter performance.
3Productivity
If the inlet opening is larger, then more liquid can be recirculated, but foreign objects can more easily enter the inlet opening
Solution Approach 1:
The artificial boundary creates a localized backflow zone with specific flow characteristics near the inlet opening. This local modification of flow quality retards foreign objects in the high-velocity recirculation stream, allowing a larger inlet opening to maintain high liquid recirculation rates while preventing foreign object entry.
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 enhances filtration efficiency, prevents soil re-deposition on utensils, and reduces maintenance requirements by effectively cleaning the filter throughout the dishwasher's operation, ensuring optimal performance and cleanliness.
Implementation Method 1
efficiently separates soil particles from the wash fluid through centrifugal force and pressure gradients
Implementation Method 2
creates a backflow zone to prevent foreign objects from entering the recirculation flow path
Data Source
AI summary
A dishwasher with a tub at least partially defining a washing chamber, a liquid spraying system, a liquid recirculation system defining a recirculation flow path, and a liquid filtering system. The liquid filtering system includes a rotating filter disposed in the recirculation flow path to filter the liquid.