Drain Pump Impeller Clearance Design to Prevent Sand Clogging
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Solution Overview
Problem
Conventional drain pumps in washing machines are prone to clogging due to sand and other large particles becoming trapped between the impeller and the pump body, leading to decreased performance and operational issues.
Innovation Solution
The design features a pump body with a sloped outer rim and a bi-directional impeller with a cutout and seal, facilitating the removal of debris and preventing it from lodging, ensuring efficient drainage and maintaining pump performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the impeller disk extends radially outward with a small radial gap to the pump body, then the pump can effectively move wash fluid, but sand and large particles become trapped between the impeller and pump body causing clogging
Solution Approach 1:
The patent introduces a new spatial dimension by adding an axial clearance between the impeller disk and pump body, in addition to the radial gap. This axial dimension provides a third pathway for particle escape, transforming a 2D trapping problem into a 3D flow problem where particles can be redirected along the axial direction to exit through the pump inlet, thereby resolving the clogging issue while maintaining drainage efficiency
Solution Approach 2:
The patent converts the harmful effect of particles trapped in the radial gap into a beneficial flushing mechanism. By designing the impeller and pump body with specific geometric features (axial clearance, angled surfaces), the trapped particles are redirected by the fluid flow to travel axially and be flushed out through the pump inlet, transforming the clogging problem into a self-cleaning feature
2Device complexity
If sand and particles accumulate in the space between the impeller disk and pump body, then the pump structure remains simple, but the drain pump performance decreases and it clogs
Solution Approach 1:
The patent incorporates preliminary design features during manufacturing that prevent particle accumulation before it occurs. The axial clearance and angled surfaces are built into the pump structure from the outset, creating automatic particle redirection pathways that prevent clogging before it can develop, thereby maintaining high performance without requiring complex operational interventions
Solution Approach 2:
The pump design enables self-cleaning functionality where the fluid flow itself, driven by the impeller, automatically redirects and flushes out particles that enter the clearance space. This self-service mechanism eliminates the need for external cleaning systems or complex maintenance procedures, maintaining simple structure while ensuring sustained performance
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 clogging by allowing sand and debris to flush out, maintaining high flow rates and preventing performance degradation, thus ensuring reliable operation of the drain pump.
Implementation Method 1
The outer rim has a sloped face that slopes outward along the radial direction from the axis of rotation as the sloped face extends away from the base wall along the axial direction
Implementation Method 2
an impeller positioned within the pump chamber and rotatable about the axis of rotation, the impeller having a shaft positioned within the well, a plurality of blades extending outward from the shaft along the radial direction
Data Source
AI summary
A washing machine appliance and pumps therefore are provided. In one example aspect, a drain pump for a washing machine appliance includes features for improving pump performance and sand and debris management. The drain pump includes a pump housing and a pump body defining a pump chamber in which an impeller having a disk and blades is rotatably mounted. The pump body has a base defining a pump body recess. An outer rim of the base defines an outer periphery of the pump body recess. The disk is spaced from the outer rim so that sand and debris can be flushed from beneath the impeller. A sloped surface of the outer rim also facilitates removal of sand and debris from beneath the impeller. A labyrinth is defined beneath blades of the impeller to prevent sand and debris from entering an area between a seal and a shaft of the impeller.