Laundry Drum Hole Layout for Water Flow and Drum Stiffness

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Solution Overview

Problem

Front-loading laundry washing machines face challenges in achieving high washing efficiency and stiffness while maintaining cost-effectiveness and avoiding damage to laundry due to the limitations of through hole design, which affects water circulation and laundry support during washing and spinning cycles.

Innovation Solution

A rotatable drum with a cylindrical lateral wall featuring groups of through holes arranged in a hexagonal pattern, where the first and second interspaces have the same radial distance from the rotation axis, allowing for unobstructed water flow and air circulation, enhancing washing and drying efficiency, and providing additional wringing action during spinning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the through holes density is increased to maximize the overall perforated area, then washing efficiency is improved, but production costs increase and drum stiffness is compromised

Engineering Contradiction:
Improvewashing efficiencyVSAvoidproduction cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The through holes are segmented into groups arranged in a hexagonal pattern, where each group contains multiple holes positioned at specific intervals. This segmentation allows water to flow through multiple holes in sequence as the drum rotates, maximizing washing efficiency without requiring excessive hole density that would compromise structural integrity or increase manufacturing costs

Inventive Principle:
Principle #1Segmentation

2Productivity

If the nominal diameter of through holes is increased to improve water outflow, then washing efficiency is improved, but laundry textile is damaged

Engineering Contradiction:
Improvewater outflow efficiencyVSAvoidlaundry textile damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The water outflow function is segmented across multiple smaller through holes arranged in hexagonal groups rather than using fewer larger holes. This distribution allows efficient water evacuation while maintaining adequate support for the laundry textile, preventing excessive local stretching and fiber damage

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution transitions from considering only hole diameter (one dimension) to incorporating hole arrangement pattern and spacing (additional dimensions). The hexagonal pattern with specific radial distances creates optimal water flow paths without requiring increased hole diameter, thus avoiding textile damage

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If the through holes density is increased to improve water circulation, then washing efficiency is improved, but drum stiffness is compromised

Engineering Contradiction:
Improvewater circulation efficiencyVSAvoiddrum stiffness
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The perforated area is segmented into discrete hexagonal groups with specific spacing, allowing water circulation through multiple holes per group while maintaining sufficient solid material between groups to preserve drum stiffness and structural integrity

Inventive Principle:
Principle #1Segmentation

4Volume of moving object

If the nominal internal volume of drum is increased to accommodate more laundry, then laundry capacity is improved, but water outflow is blocked due to increased laundry thickness

Engineering Contradiction:
Improvelaundry capacityVSAvoidwater outflow efficiency
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The solution addresses the blocking issue by changing the spatial arrangement of through holes from a simple grid to a hexagonal pattern with optimized radial distances. This dimensional optimization creates adequate flow paths through the laundry mass, maintaining water outflow efficiency even with increased laundry volume and thickness

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 achieves optimal water exchange and evacuation during washing cycles, deep wetting action, and effective drying, while maintaining drum stiffness and reducing production costs, with a unique appearance distinguishing it from conventional drums.

Implementation Method 1

the substantially cylindrical lateral wall being provided with at least one perforated portion having a plurality of through holes

Methodology Applied
Scientific EffectWater flow through perforations: Porosity

Implementation Method 2

a rotatable drum for housing the laundry to be washed, the rotatable drum being housed inside the washing tub to rotate about its longitudinal axis

Methodology Applied
Scientific EffectRotational motion:

Implementation Method 3

a door hinged to the casing to rotate to and from a closing position in which the door closes the opening to seal the washing tub

Methodology Applied
Scientific EffectRotational motion:

Data Source

PatentEP2832916B1Laundry treating machine including a rotatable drum
Publication Date: 2018.03.07 ELECTROLUX APPLIANCES
  • EP2832916B1 patent drawingFigure 1
  • EP2832916B1 patent drawingFigure 2
  • EP2832916B1 patent drawingFigure 3~4

AI summary

The present invention relates to a rotatable drum (1) for a laundry treating machine (2), the rotatable drum (1) comprising a substantially cylindrical lateral wall (13a) having a rotation axis (L), the substantially cylindrical lateral wall (13a) being provided with at least one perforated portion (13a') having a plurality of through holes (15) which are arranged in an orderly manner so as to form groups (15a) of through holes (15), said through holes (15) in each group (15a) being separated one another by first interspaces (15b), said groups (15a) being in turn separated one another by second interspaces (15c) lacking through holes. Advantageously, said first interspaces (15b) and said second interspaces (15c) of said at least one perforated portion (13a') have substantially the same radial distance from said rotation axis (L).