Dishwasher Steam Drying Cycle to Reduce Water Usage and Overheating

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Solution Overview

Problem

Conventional dishwashers fail to uniformly distribute steam to all areas of the washing space, particularly the front and rear portions of racks, leading to inefficient cleaning and temperature distribution, and excessive water usage in drying cycles, which can cause overheating and energy inefficiency.

Innovation Solution

The dishwasher incorporates a control method that includes a pre-washing cycle with unscented wash water, a main-washing cycle with steam addition, and a steam refresh course, utilizing steam nozzles on the door and rear surface to ensure steam reaches all areas, and employs residual heat to conserve water and energy, while the steam drying cycle uses steam instead of hot water to dry dishes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If steam is supplied only via the lateral surface of the tub, then the steam generator can be简单地 installed, but uniform temperature distribution in the washing space cannot be achieved

Engineering Contradiction:
Improvesteam generator installationVSAvoidtemperature distribution uniformity
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The steam supply system is segmented into multiple independent nozzles distributed at different locations (lateral surface, front surface, rear surface) of the tub. Each nozzle independently supplies steam to specific areas, collectively achieving uniform temperature distribution while maintaining simple installation of individual components

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The steam supply is extended from a single lateral dimension to multiple spatial dimensions by adding nozzles on front and rear surfaces. This multi-dimensional steam distribution eliminates dead zones and ensures uniform temperature throughout the washing space

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

2Device complexity

If steam is injected only to the washing objects placed in both side areas of the rack, then the steam nozzle arrangement is simple, but washing objects in the central area cannot be effectively treated

Engineering Contradiction:
Improvesteam nozzle arrangementVSAvoidwashing effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The steam treatment function is segmented across multiple nozzles positioned at lateral, front, and rear surfaces. This segmentation ensures that steam reaches all areas including the central region of the rack, maintaining washing effectiveness without complexifying the overall system

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Steam injection is extended from lateral-only positioning to multi-positional distribution including front and rear surfaces. This spatial expansion ensures comprehensive coverage of washing objects regardless of their position on the rack

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

3Ease of operation

If a final rinsing cycle with heated hot wash water is implemented to raise dish temperature and evaporate water, then dishes can be dried, but the amount of hot wash water supplied is excessively increased

Engineering Contradiction:
Improvedrying functionVSAvoidhot wash water consumption
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The mechanical system of supplying large amounts of heated wash water for drying is replaced with a thermal system using steam injection. Steam directly heats and dries dishes through phase change and evaporation, eliminating the need for excessive hot water consumption while maintaining effective drying function

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

Solution Approach 2:

The drying process utilizes phase transitions of water (liquid to vapor) through steam injection. The steam condenses on cooler dish surfaces, transfers latent heat, and causes evaporation of residual water, achieving drying through thermal phase change rather than mechanical water removal

Inventive Principle:
Principle #36Phase transitions

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 solution allows for uniform steam distribution to all areas of the dishwasher, reduces water usage, prevents overheating, and enhances energy efficiency by using residual heat and steam drying, effectively cleaning and drying dishes while minimizing water and energy consumption.

Implementation Method 1

The conventional dishwasher typically heats the wash water stored in the sump to generate heated water, using a heater provided in the sump or generates steam, using an auxiliary steam generator provided therein

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

generates steam, using an auxiliary steam generator provided therein

Methodology Applied
Scientific EffectPhase change (water to steam): Phase Change

Implementation Method 3

an injection arm for injecting wash water to the racks

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 4

a pump for supplying the wash water stored in the sump to the injection arm

Methodology Applied
Scientific EffectPumping: Pump

Data Source

PatentEP3187090B1Dishwasher and control method thereof
Publication Date: 2020.09.09 LG ELECTRONICS INC
  • EP3187090B1 patent drawingFigure 1
  • EP3187090B1 patent drawingFigure 2
  • EP3187090B1 patent drawingFigure 3

AI summary

Disclosed a control method of a dishwasher comprising a steam drying cycle (S500) for drying the washing objects by suppling steam; wherein the steam drying cycle (S500) comprises: a drying steam water supply step (S502) supplying water into the circulation pump (8);and a drying steam supply step (S504) supplying steam generated inside the circulation pump (8) to the tub (2) so as to dry the washing objects, and controlling a water level of the water supplied in the drying steam water supply step (S502) to be lower than a steam outlet hole (843) provided in the circulation pump (8).