Laundry Drum Gap Design to Reduce Water Ring Formation During Spin
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Solution Overview
Problem
The existing household appliances face challenges in efficiently removing water from the gap between the laundry drum and the tub during spin cycles, leading to the formation of a water ring that complicates drainage due to localized radial expansion and high dynamic pressure.
Innovation Solution
A household appliance design featuring a gap between the laundry drum and tub with varying radial dimensions, where the gap's azimuthal section extends over at least 80°, with a continuous increase in radial dimension from the first section end to the second, reducing dynamic pressure by at least 30% to facilitate improved water drainage and minimize water ring formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the gap has localized radial expansion only in a small lower area, then the structure is simple, but water drainage is poor and water ring formation occurs
Solution Approach 1:
The gap is designed with non-uniform radial dimensions where the radial distance between the laundry drum and tub varies continuously in the circumferential direction. Specifically, the gap width is smaller at the inlet side (where water enters from the drum) and progressively larger toward the outlet side, creating localized quality variations that optimize water flow guidance and drainage efficiency while preventing water ring formation.
Solution Approach 2:
The invention transitions from localized radial expansion (point-like expansion in a small lower area) to extended radial dimension variation across a large circumferential section (at least 80°). This dimensional expansion in the circumferential direction allows water to be guided more effectively along the gap, improving drainage without significantly increasing structural complexity.
2Length of stationary object
If the gap has small radial dimensions, then the structure is compact, but dynamic pressure is high making drainage difficult
Solution Approach 1:
The radial dimension of the gap is varied continuously in the circumferential direction to change the dynamic pressure distribution. By making the gap narrower at the inlet and progressively wider toward the outlet, the design exploits pressure gradient effects to facilitate water flow from high-pressure to low-pressure zones, reducing overall dynamic pressure buildup while maintaining compact dimensions.
3Speed
If water flows at high speed in the gap, then pumping effect is strong, but water ring forms making drainage difficult
Solution Approach 1:
The gap geometry is designed to dynamically adapt to water flow conditions by utilizing the continuous circumferential variation in radial dimensions. As water enters the gap at high speed, the progressively increasing gap width allows for controlled deceleration and pressure equalization, preventing water ring formation while maintaining effective pumping action throughout the spin cycle.
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 design enhances water drainage management by reducing dynamic pressure and calming the water flow, minimizing water ring formation and enabling continuous pumping across all spin speeds, while also reducing backflow and re-humidification.
Implementation Method 1
Depending on the speed of the laundry drum and the geometric dimensions of the gap, a certain dynamic pressure occurs along the gap between the laundry drum and the tub. This dynamic pressure also leads to a reduction in the static pressure in the gap.
Implementation Method 2
When the household appliance spins, jets of water constantly emerge radially from the laundry drum at a relatively high speed. This means that water gets into the gap between the tub and the laundry drum. Due to the rotating laundry drum, a water flow occurs in the gap.
Implementation Method 3
The first section end is arranged in the 3 o'clock position or the 9 o'clock position. This is advantageous because, due to the intended arrangement of the household appliance, the falling speed or the weight of the water is already fully effective at the first end of the section. The water entering the gap then no longer has to be guided in a quasi horizontal direction along the outside of the laundry drum, but can practically flow completely downwards.
Data Source
Figure 1~2
AI summary
One aspect of the invention relates to a household appliance (1) for the care of laundry items, comprising a housing (2) in which a washing drum (3) of the household appliance (1) and a tub (4) of the household appliance (1) surrounding the washing drum (3) in a circular direction about an axis of rotation (A) of the washing drum (3) are arranged, wherein a gap (6) is formed in the radial direction to the axis of rotation (A) between the washing drum (3) and the tub (4), wherein the gap (6) is formed with varying radial dimension when viewed in the circular direction about the axis of rotation (A), wherein the gap (6) has a circular section (11) which extends over at least 80° and in which the radial dimension increases continuously from a first section end (12) to a second section end (13).