Dishwasher Impeller Jet Control for Complete Upper Rack Coverage

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Solution Overview

Problem

Conventional dishwashers often fail to effectively wash dishes in the central and peripheral areas of the upper rack due to the limited reach of the umbrella jet generated by the impeller, leaving some dishes unwashed.

Innovation Solution

The method involves a dishwasher with a centrifugal pump that adjusts rotation speed to generate multiple water jets with varying diameters, ensuring all areas of the upper rack are washed by actuating the pump to produce jets with specific profiles and areas of impact, and varying the water temperature and dispensing duration to optimize washing cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a single fixed-speed pump is used to generate an umbrella jet, then the device complexity is reduced, but the washing coverage area is insufficient

Engineering Contradiction:
Improvewashing coverage areaVSAvoidpump control system complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the pump rotation speed variable rather than fixed. The control unit dynamically adjusts the pump's rotation speed according to a predetermined program, enabling the water jet to cover different areas of the upper rack at different times. This resolves the contradiction by allowing a single pump to achieve comprehensive washing coverage through speed variation instead of requiring multiple fixed-speed pumps or complex mechanical positioning systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the pump, specifically the rotation speed, to control the washing process. By varying the rotation speed parameter, the system adjusts the water jet's amplitude and coverage area. This parameter change approach allows the single pump to adapt to different washing needs and cover the entire upper rack area, resolving the contradiction between device simplicity and washing coverage.

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If the pump rotation speed is increased to expand the jet amplitude, then the washing coverage is improved, but the energy consumption increases

Engineering Contradiction:
Improvejet coverage areaVSAvoidpump energy consumption
Core Design Contradiction:
Area of stationary objectVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by varying the pump rotation speed in a predetermined sequence rather than maintaining a constant high speed. The control unit programs the pump to operate at different speeds at different times during the washing cycle, expanding the jet amplitude only when needed to cover specific areas. This periodic variation in speed reduces overall energy consumption while still achieving complete washing coverage of the upper rack.

Inventive Principle:
Principle #19Periodic action

3Productivity

If the umbrella jet is used to wash the upper rack, then the device complexity is minimized, but the washing effectiveness in central and peripheral areas is insufficient

Engineering Contradiction:
Improvewashing effectivenessVSAvoidadaptability to different washing patterns
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent makes the washing system dynamic by enabling the pump speed to vary according to a predetermined program. This allows the single umbrella jet to adapt its coverage pattern over time, effectively washing both central and peripheral areas of the upper rack. The dynamic speed adjustment provides the adaptability needed to ensure comprehensive washing effectiveness without requiring multiple complex spraying mechanisms.

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 approach ensures complete washing of all dishes on the upper rack by adjusting the water jet's amplitude and temperature, adapting to different washing requirements and improving efficiency by ensuring all areas are covered, including the inner walls of the dishwasher at higher speeds.

Implementation Method 1

a supply pump, generally a centrifugal pump to feed the washing water alternately and sequentially to the dispensers or to the impeller

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

sprayers of this type consist of an impeller mounted idly to generate a jet with an umbrella profile

Methodology Applied
Scientific EffectImpeller rotation: Impeller

Data Source

PatentEP2756788B1Dish washing method
Publication Date: 2020.03.25 WHIRLPOOL EMEA SPA
  • EP2756788B1 patent drawingFigure 1
  • EP2756788B1 patent drawingFigure 2

AI summary

A dish washing method, comprising the steps of: distributing washing water to at least one impeller (29) arranged above a rack (39) for containing dishes; and generating through the impeller (29) a jet of water (69a-69c) directed at a predefined area (79a-79c) of the rack (39) to hit the dishes with said water; said step of distributing the water being actuated by supplying the water to the impeller (29) according to a plurality of predefined values each of which represents a different area (79a-79c) subtended by a respective jet (69a-69c) dispensed from the impeller (29).