Dishwasher appliance having backflow device
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Solution Overview
Problem
Dishwasher appliances face the issue of reverse fluid flow through the filter assembly after a wash cycle, which can carry trapped soils back into the wash chamber, contaminating the fluid and potentially damaging the pump.
Innovation Solution
A filter assembly with a backflow device positioned within the second filter, allowing fluid flow in the open position and preventing it in the closed position, is used to prevent reverse fluid flow by moving automatically to the closed position when opposite flow is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the pump stops providing pressurized fluid through conduits at the end of a wash cycle, then the pump conserves energy and stops operation, but the weight of fluid in the conduits causes reversal of flow through the pump and filter assembly, carrying trapped soils back into the wash chamber
Solution Approach 1:
The backflow prevention device is positioned within the filter assembly to proactively counteract the harmful reverse flow before it can contaminate the wash chamber. The device includes a backflow prevention member that automatically closes in response to reverse flow conditions, preventing contaminated fluid from entering the wash chamber while allowing normal forward flow during operation
Solution Approach 2:
The backflow prevention device acts as an intermediary element between the filter assembly and the wash chamber. It includes a backflow prevention member that can be positioned to block the inlet of the filter assembly, serving as a mediator that prevents direct communication between the contaminated fluid path and the clean wash chamber
2Reliability
If a filter assembly is provided to trap soils carried with wash fluid, then the pump is protected and fluid is recirculated cleanly, but trapped soils can be carried back into the wash chamber when fluid flow reverses through the pump
Solution Approach 1:
The backflow prevention device proactively prevents the release of trapped soils by closing the backflow prevention member before reverse flow can carry contaminated fluid back into the wash chamber. This preliminary anti-action maintains the reliability benefit of soil trapping while eliminating the harmful release of trapped soils
Solution Approach 2:
The filter assembly is segmented into functional zones: a first filter for initial filtration, a second filter for fine filtration, and a backflow prevention device for flow direction control. This segmentation allows each component to specialize in its function while working together to prevent soil release
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 the backflow of contaminated fluid into the wash chamber, maintaining the cleanliness of the wash fluid and protecting the pump, ensuring a continuous clean wash cycle.
Implementation Method 1
the weight of the fluid positioned in the conduits may cause a reversal of the flow through the pump
Implementation Method 2
a filter assembly to trap at least certain of the soils carried with the wash fluid
Data Source
AI summary
A filter assembly for a dishwasher appliance is provided including a first filter, a second filter, and a backflow device. The backflow device is positioned within the second filter and movably attached to the second filter, such that backflow device is movable between an open position and a closed position. When in the closed position, the backflow device prevents a flow of fluid through an inlet of the second filter.