Drum Washer Tub Cleaning Using Controlled Water Circulation

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Solution Overview

Problem

Conventional drum-type washing machines do not effectively clean the entire inner circumferential surface of the tub, including the upper parts, leading to pollutant and scale accumulation, which can cause bad smells and laundry pollution, while pulsator-type machines require excessive water and environmentally unfriendly detergents for cleaning. Additionally, gasket cleaning is difficult due to its sectional shape and hidden pollutant accumulation.

Innovation Solution

A drum-type washing machine with a control unit that adjusts the rotation speed and water level to circulate wash water along the tub's inner surface, using steam to soak pollutants, and a mechanism to introduce wash water to the gasket for effective cleaning without additional devices or harsh detergents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the spin-drying tub is rotated at high speed to clean the water storage tub, then the cleaning effectiveness is improved, but excessive load is applied to the motor due to friction with wash water

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidmotor load
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention dynamically adjusts the rotation speed of the spin-drying tub based on operational phase. During washing, the tub rotates at high speed to generate strong water currents for cleaning. During spin-drying, the rotation speed is reduced to minimize motor load while still maintaining cleaning effectiveness through the residual water motion and centrifugal force.

Inventive Principle:
Principle #15Dynamics

2Speed

If the spin-drying tub is rotated at very high speed to reach upper side parts, then the water can reach higher areas, but it becomes difficult for wash water to reach the upper side part of the inner circumferential surface

Engineering Contradiction:
Improverotation speedVSAvoidwater distribution coverage
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The invention introduces a water supply device that operates in the vertical dimension to complement the horizontal rotation. Water is supplied from above to fall onto the spin-drying tub surface, using gravity to ensure coverage of upper areas that rotation alone cannot reach. This multi-dimensional approach ensures complete coverage without requiring excessively high rotation speeds.

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

3Reliability

If special detergent with strong cleaning force is used to clean the water storage tub, then the cleaning effectiveness is improved, but the detergent contains large amount of chemical components causing water pollution

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidwater pollution
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention replaces chemical cleaning methods with mechanical cleaning mechanisms. The spin-drying tub rotation generates strong water currents and turbulence that mechanically remove pollutants and scale from the water storage tub surface. This mechanical action substitutes for chemical detergents, achieving effective cleaning without introducing harmful chemical components into the environment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If the drum is rotated at high speed during washing, then the washing effectiveness is improved, but the laundry may be damaged due to excessive friction and impact

Engineering Contradiction:
Improvewashing effectivenessVSAvoidlaundry integrity
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The invention employs periodic variation in drum rotation speed during the washing cycle. The drum alternates between high-speed rotation for effective washing action and lower-speed periods that reduce friction and impact on laundry. This periodic action maintains washing effectiveness while preventing excessive mechanical stress that could damage fabric integrity.

Inventive Principle:
Principle #19Periodic action

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 allows for thorough cleaning of the tub's inner surface, including hard-to-reach areas, and simultaneous gasket cleaning, reducing the need for special detergents and minimizing environmental impact by using a controlled water circulation and steam treatment.

Implementation Method 1

the control unit controls the rotation speed of the drum such that wash water supplied into the tub circulates along the inner circumferential surface of the tub

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

using steam to soak pollutants

Methodology Applied
Scientific EffectSteam heating: Heating

Data Source

PatentEP1945848B2Drum-type washing machine and tub cleaning method of the same
Publication Date: 2015.02.25 LG ELECTRONICS INC
  • EP1945848B2 patent drawingFigure 1
  • EP1945848B2 patent drawingFigure 2
  • EP1945848B2 patent drawingFigure 3~4

AI summary

A drum-type washing machine that is capable of easily cleaning a tub (110) and a tub cleaning method of the same are disclosed. A drum-type washing machine that is capable of cleaning a gasket (140) along with cleaning of the tub and a gasket cleaning method of the same are also disclosed. The drum-type washing machine includes a tub (110) mounted in a cabinet (101) such that wash water is supplied into a tub (110), a drum (106) rotatably mounted in the tub (110) such that laundry is put into the drum (106), a motor (104) for rotating the drum (106), and a control unit (160) for controlling the driving of the motor (104) such that, when the drum (106) is rotated, the wash water supplied into the tub (110) reaches the upper part of the inner circumferential surface of the tub (110) so as to clean the inner circumferential surface of the tub (110).