Dishwasher Air Heating Strategy for Gentle Washing and Drying

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Solution Overview

Problem

Dishwashers often subject sensitive items to excessive thermal stress due to rapid heating methods, which can damage them during washing and drying processes.

Innovation Solution

The method employs an air heater to gently heat liquid during multiple program steps, with a desorption phase of a reversibly dehydratable drying agent like zeolite distributed across these steps, and a water heater used intermittently for faster heating, ensuring complete desorption and energy-efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a continuous-flow heater is used to heat liquid quickly, then heating speed is improved, but thermal stress on sensitive items worsens

Engineering Contradiction:
Improveheating speedVSAvoidthermal stress on items
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The heating process is segmented into multiple stages using different heating means. A first heating means (air heater) provides gentle heating during initial program steps, while a second heating means (water heater) provides rapid heating when needed. This segmentation allows the system to achieve fast heating when required while protecting sensitive items during vulnerable phases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different heating means based on the program step and requirements. The control unit activates the first heating means during specific program steps (pre-rinse, cleaning, intermediate rinsing) and the second heating means during other steps (final rinsing), creating a dynamic heating strategy that adapts to protect items while maintaining efficiency.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the washing program duration is extended to achieve complete desorption, then desorption completeness is improved, but productivity worsens

Engineering Contradiction:
Improvedesorption completenessVSAvoidwashing program duration
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The desorption process is initiated in advance during earlier program steps (pre-rinse, cleaning, intermediate rinsing) using the first heating means. This preliminary desorption prepares the drying agent for the final drying phase, ensuring complete desorption is achieved without extending the overall program duration, as the final drying step can then proceed immediately with fully prepared drying agent.

Inventive Principle:
Principle #10Preliminary action

3Temperature

If the first heating means is operated continuously during all program steps, then heating effectiveness is improved, but energy consumption worsens

Engineering Contradiction:
Improveheating effectivenessVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The first heating means is operated periodically during specific program steps (pre-rinse, cleaning, intermediate rinsing) rather than continuously. The control unit activates the heating means only when required for specific functions (heating liquid for cleaning, supporting desorption) and deactivates it during other steps (final rinsing with second heating means), reducing overall energy consumption while maintaining heating effectiveness when needed.

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

This approach reduces thermal stress on items, achieves intensive cleaning and improved drying, while maintaining a shorter washing program duration and ensuring energy efficiency.

Implementation Method 1

liquid is heated at least twice with a first heating means... an air heater is used as the first heating means... This allows the items to be washed to be heated gently

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

a water heater is used as the second heating means... the second heating means is operated at least intermittently during at least two program steps... allows further, faster heating

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

a desorption phase of a reversibly dehydratable drying agent, in particular zeolite, of a sorption drying system being distributed over at least two program steps... the reversibly dehydratable drying material is at least partially desorbed during heating with the air heater

Methodology Applied
Scientific EffectAdsorption/Desorption: Adsorption

Data Source

PatentEP2326234B1Method for operation of a dishwasher
Publication Date: 2015.09.23 BSH HAUSGERATE GMBH
  • EP2326234B1 patent drawingFigure 1
  • EP2326234B1 patent drawingFigure 2
  • EP2326234B1 patent drawingFigure 3

AI summary

The invention relates to a method for operation of a dishwasher (GS), in particular of a domestic dishwasher, in which the liquid is heated at least twice by a first heating means. The invention provides for an air heater (HZ) to be used as the first heating means.