Variable-Speed Fan Impeller Drying for Residual Water in Dishwashers

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Solution Overview

Problem

Conventional dishwasher drying systems are ineffective in completely removing liquid from depressions in washware items, leading to residual water that can cause unsightly deposits and requires manual intervention, which is inconvenient and time-consuming.

Innovation Solution

A rotatable fan wheel with a variable-speed motor is integrated into the dishwasher, allowing for different air flow strengths and speeds to be used during the drying cycle, including a high-speed blow-off phase followed by a convection drying phase, to effectively remove liquid from depressions and reduce energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional drying systems are used, then energy consumption is reduced, but liquid in depressions cannot be completely removed

Engineering Contradiction:
Improveresidual liquid in depressionsVSAvoidenergy consumption
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The fan wheel operates with variable speed, switching between a first operating state (lower speed) and a second operating state (higher speed). This dynamic operation allows the system to achieve effective liquid removal in depressions while managing energy consumption, as the high-speed state is only activated when needed for blow-off phases.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The drying process alternates between different operating states of the fan wheel. The control device switches between the first and second operating states periodically, using high-speed operation for brief blow-off phases to remove liquid from depressions, then returning to lower-speed convection drying, thereby balancing effectiveness with energy efficiency.

Inventive Principle:
Principle #19Periodic action

2Use of energy by moving object

If fan speed is varied over time, then energy consumption and noise are reduced, but control complexity increases

Engineering Contradiction:
Improveenergy consumptionVSAvoidmotor speed control
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The motor's rotational speed is made variable through electronic control, allowing the fan wheel to operate in different states. This dynamic speed control enables the system to optimize energy consumption and noise levels while maintaining effective drying performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control device changes the operational parameters of the motor, specifically its rotational speed, to switch between different operating states. By adjusting this key parameter, the system achieves energy efficiency and noise reduction without requiring complex mechanical modifications.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If conventional drying methods are used, then device complexity is low, but manual intervention is required to remove residual liquid

Engineering Contradiction:
Improvemanual liquid removalVSAvoiddrying system configuration
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The drying system is designed to automatically remove liquid from depressions without requiring manual intervention. The variable-speed fan wheel, controlled by a control device, performs the blow-off function automatically, eliminating the need for users to manually tilt or wipe items after washing.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The automatic blow-off function is achieved through dynamic speed control of the fan wheel. The system automatically transitions to high-speed operation during blow-off phases, effectively removing liquid from depressions without user intervention, thereby improving ease of operation despite increased device complexity.

Inventive Principle:
Principle #15Dynamics

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 efficiently removes liquid from washware items, reduces energy usage, and minimizes noise levels by varying fan speed, ensuring thorough drying without manual intervention and preventing water marks.

Implementation Method 1

at least one rotatable fan wheel (17) is arranged in the washing compartment (2), with which air can be sucked in on the one hand and air can be blown out on the other hand

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

at least one rotatable fan wheel (17) is arranged in the washing compartment (2), with which air can be sucked in on the one hand and air can be blown out on the other hand

Methodology Applied
Scientific EffectCentrifugal Force: Centrifugal Force

Data Source

PatentEP3654814B1Dishwasher comprising at least one fan impeller in the dishwashing compartment
Publication Date: 2021.09.08 BSH HAUSGERATE GMBH
  • EP3654814B1 patent drawingFigure 1
  • EP3654814B1 patent drawingFigure 2
  • EP3654814B1 patent drawingFigure 3

AI summary

A dishwasher (1), in particular a domestic dishwasher, comprising a dishwashing compartment (2) for receiving items of washware, such as tableware, glasses, cutlery or the like, for example, is designed such that at least one rotatable fan impeller (17) is arranged in the dishwashing compartment (2), it being possible firstly to draw in air and secondly to blow out air using said fan impeller, wherein a motor (18), the rotation speed of which can be varied over time, is associated with the at least one fan impeller (17).