Dishwasher Delayed Start Wetting for Lower-Energy Cleaning

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Solution Overview

Problem

Existing delayed start dishwashers do not effectively enhance the cleaning effect during the waiting phase, leading to suboptimal dirt removal and increased energy consumption.

Innovation Solution

The dishwasher controller wets dishes during the waiting phase, reduces water and energy usage by partial water replacement between phases, and adjusts temperatures based on waiting phase duration to soften dirt, allowing for reduced intensity in subsequent wash phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If the dishwasher uses a delayed start with a waiting phase, then energy consumption is reduced by delaying the heating process, but the cleaning effectiveness deteriorates because dirt remains dry and harder to remove

Engineering Contradiction:
Improveenergy consumptionVSAvoidcleaning effectiveness
Core Design Contradiction:
Use of energy by stationary objectVSManufacturing precision

Solution Approach 1:

The controller activates spray means during the waiting phase to wet the dishes before the actual washing program begins. This preliminary wetting action softens the dirt on the dishes, making it easier to remove during the subsequent wash phases. The spray means are activated at specific time points during the waiting phase to ensure the dishes are adequately moistened without requiring full heating, thus maintaining cleaning effectiveness while preserving energy benefits of delayed start

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The controller modifies the operational parameters of the spray means during the waiting phase, activating them at specific time points to deliver water to the dishes. This parameter change (from inactive to active spray) transforms the state of the dishes from dry to wet, enabling effective dirt removal in subsequent phases while maintaining the energy-saving delayed start functionality

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the dishwasher wets dishes during the waiting phase, then cleaning effectiveness is improved by softening dirt, but water consumption increases

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidwater consumption
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

Instead of continuously wetting the dishes throughout the entire waiting phase, the controller applies partial wetting by activating the spray means only at specific time points. This partial action is sufficient to soften the dirt on the dishes without unnecessarily consuming large amounts of water. The spray duration and timing are optimized to achieve the minimum required wetting effect

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The controller implements periodic wetting by activating the spray means at predetermined time intervals during the waiting phase rather than continuously. This periodic action allows the water to be effectively utilized for softening dirt while reducing overall water consumption compared to continuous spraying. The intervals between spray activations are calculated to maintain dirt softening while minimizing water use

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If the dishwasher replaces all process water between pre-rinse and main rinse phases, then cleaning effectiveness is improved with fresh water, but energy consumption increases due to heating new water

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by stationary object

Solution Approach 1:

The controller implements partial water replacement between the pre-rinse and main rinse phases rather than complete replacement. It retains a portion of the process water that is still suitable for use and only replaces the contaminated portion. This approach recovers usable water from the pre-rinse phase, reducing the amount of new water that needs to be heated and thus lowering energy consumption while maintaining adequate cleaning effectiveness

Inventive Principle:
Principle #34Discarding and recovering

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

Improves cleaning effectiveness by loosening dirt before the wash phase, reducing energy consumption, and maintaining water efficiency without unnecessary water usage.

Implementation Method 1

When the delayed start is activated, the controller is designed to heat the process water to a lower temperature in the pre-wash phase and/or main wash phase than in the pre-wash phase and/or main wash phase without a delayed start. This exploits the fact that the dirt has already softened thanks to wetting in the waiting phase

Methodology Applied
Scientific EffectThermal softening: Heating

Implementation Method 2

The controller is designed to reduce the temperature of the process water in the pre-rinse phase (B) and/or main rinse phase (C) with a delayed start compared to the corresponding temperature without a delayed start by a value that depends on the length of the waiting phase (A)

Methodology Applied
Scientific EffectTemperature reduction: Cooling

Data Source

PatentEP2868251B1Dishwasher with start delay
Publication Date: 2017.04.19 V-ZUG AG
  • EP2868251B1 patent drawingFigure 1~3

AI summary

A dishwasher offers the option of starting the cleaning program with a delayed start. In this case, in a waiting phase (A) before the cleaning program, the dishes are regularly wetted in wetting steps (20-1, 20-2, . . . ) in order to soften or at least partially dissolve the dirt.