Washer Drain Pump Venting Geometry for Self-Priming
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Solution Overview
Problem
Existing drain pumps in washing appliances face inefficiencies due to trapped air, which impedes or prevents liquid priming, as not all air is bled off from the impeller chamber.
Innovation Solution
A pump design featuring a pump casing with an inclined inlet conduit and a ramped surface on the ceiling that allows air to rise and vent out of the impeller chamber, ensuring self-priming by facilitating the expulsion of trapped air through the inlet conduit when the impeller is stationary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional drain pump design is used with air bleeding through the soil pipe, then the pump can operate, but trapped air remains in the impeller chamber which reduces pump efficiency
Solution Approach 1:
The pump housing is segmented into two chambers by a partition wall: a first chamber for receiving water from the wash chamber and a second chamber for air venting. This segmentation allows air and water to be separated and handled independently, enabling complete air removal while maintaining pump operation.
Solution Approach 2:
A self-closing valve is introduced as an intermediary component in the air vent line. This valve automatically opens to allow air escape and closes to prevent water loss, mediating between the need to remove air and the need to maintain water in the pump chamber for efficient operation.
2Ease of operation
If air is bled through the soil pipe, then some air can be removed, but not all trapped air is bled off requiring the impeller to overcome remaining air
Solution Approach 1:
The air venting chamber and self-closing valve mechanism are designed to automatically remove air from the impeller chamber before the pump begins its priming operation. This preliminary air removal action eliminates the need for the impeller to work against trapped air, improving priming efficiency.
Solution Approach 2:
The self-closing valve automatically performs the air bleeding function without manual intervention. It opens when air pressure builds up and closes automatically when air is expelled, providing self-service air removal that ensures complete air evacuation from the impeller chamber.
3Productivity
If the inlet conduit is positioned at a small angle above horizontal, then air can rise and vent out when the impeller is not rotating, but this requires specific geometric configuration
Solution Approach 1:
The inlet conduit is oriented at a specific angle above the horizontal plane, utilizing the vertical dimension to enable air to rise and escape. This angular orientation creates a path that leverages gravity and buoyancy forces, allowing air to naturally vent without complex mechanical components.
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 design effectively vents air from the impeller chamber, ensuring efficient priming and operation of the pump, enhancing its efficiency by automatically removing trapped air.
Implementation Method 1
the upper most periphery of the inlet being above or substantially flush with the ramped surface adjacent the inlet side of the dividing wall section so that when the impeller is not rotating, air inside the pump chamber will rise up the ramped surface through the inlet and up the inlet conduit
Data Source
AI summary
A pump for washing appliance is described. The pump has a pump casing in which an impeller is located. The pump casing has an inlet and outlet, and an inlet conduit extending from the inlet at a small angle above the horizontal. The ceiling includes a downwardly extending dividing wall section extending radially from a central location to a side wall of the casing. The dividing wall is positioned between the inlet outlet. The ceiling incorporates a ramped surface rising around the central location, between the outlet side and the inlet side of the dividing wall. The ramped surface is higher adjacent the inlet side than the outlet side of the dividing wall section so that when the impeller is not rotating, air inside the pump chamber will rise up the ramped surface through the inlet and up the inlet conduit.