Dishwasher Water Inlet Venting Against Backflow Under Negative Pressure
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Solution Overview
Problem
Dishwashers face the challenge of preventing liquid from escaping into the domestic water supply system due to negative pressure conditions, which existing technologies fail to address effectively.
Innovation Solution
A dishwasher design that incorporates a water inlet device with a steam outlet opening to equalize pressure and prevent reversal of flow, featuring a ventilation opening to dissipate negative pressure and an expansion line for condensing water vapor, ensuring that liquid does not escape into the water supply system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a water inlet device is used to fill the washing container with fresh water, then the washing container can be filled efficiently, but liquid may escape into the domestic water supply system due to negative pressure
Solution Approach 1:
The water inlet device housing is divided into separate functional chambers: a first chamber for receiving fresh water from the water feed line, and a second chamber for receiving water vapor from the washing chamber. This segmentation prevents direct communication between the water supply system and the washing chamber, blocking the escape path for liquid while maintaining independent pressure equalization for each function.
Solution Approach 2:
The water inlet device housing acts as an intermediary component between the water feed line and the washing chamber. It introduces a controlled interface where water vapor can condense and be collected separately, preventing direct liquid flow back into the water supply system while still allowing pressure equalization through the expansion line.
2Reliability
If an expansion system is provided to balance pressure in the washing chamber, then pressure equalization is achieved, but the complexity of the device increases
Solution Approach 1:
The water inlet device housing performs multiple functions simultaneously: it serves as the structural housing for the water inlet mechanism, provides pressure equalization through the expansion line connection, and acts as a condensation chamber for water vapor. By combining these functions into a single component rather than separate devices, the patent reduces overall system complexity while maintaining reliable pressure equalization.
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 effectively prevents liquid from escaping into the domestic water supply system by equalizing pressure and routing water vapor for condensation, meeting test requirements and ensuring reliable operation during wash cycles.
Implementation Method 1
The expansion line can be connected at the steam outlet opening of the water inlet device to provide a condensation route for the exiting water vapor, along which route the water vapor condenses and can be collected as condensate.
Implementation Method 2
In order to fulfill the aforesaid requirement the housing of the water inlet device can have a ventilation opening. In the above-described test case ambient air can be sucked into the water feed line via the ventilation opening, and moreover instead of water vapor and/or washing liquid from the washing chamber.
Data Source
AI summary
A dishwasher includes a washing container having a washing chamber, a water feed line for filling the washing chamber with liquid, and a water inlet device connected on an inlet side to the water feed line and ending in the washing chamber on an outlet side. The water inlet device includes a steam outlet opening that ducts water vapor out of the washing container. The water inlet device prevents a negative-pressure-induced reversal of flow against the filling direction in the water feed line.