Dishwasher Spray Arm Flow Obstacle for Adaptive Jet Geometry

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Solution Overview

Problem

Existing dishwasher nozzles cannot easily adjust the geometry of the spray jet, making it difficult to reach hard-to-access areas such as pots and corners, despite the ability to create pulsating sprays.

Innovation Solution

Incorporating a flow obstacle within the spray arm adjacent to the nozzle, which can change the geometry of the emerging spray jet, allowing for adjustable and adaptable spray patterns by varying the design of the flow channels and obstacles, such as pins, ramps, or spirals, to enhance cleaning effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flow obstacle is added within the spray arm to change spray jet geometry, then cleaning effectiveness in hard-to-reach areas is improved, but device complexity increases

Engineering Contradiction:
Improvespray jet geometry adjustmentVSAvoidspray arm structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The flow obstacle is strategically positioned within the spray arm to counteract the limitation of fixed spray geometry. By placing the obstacle in the fluid path, it creates the desired spray pattern transformation without requiring complex external adjustment mechanisms, thus resolving the contradiction between adaptability and device complexity.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The flow obstacle acts as an intermediary element between the nozzle and the target surface. It modifies the spray jet geometry indirectly by interfering with the fluid flow, rather than requiring direct mechanical adjustment of the nozzle itself. This approach achieves spray pattern variation while keeping the overall device structure relatively simple.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the flow obstacle is positioned close to the nozzle to maximize geometry change, then spray jet control is improved, but pressure fluctuations increase

Engineering Contradiction:
Improvespray jet geometry controlVSAvoidpressure fluctuations
Core Design Contradiction:
Manufacturing precisionVSStress or pressure

Solution Approach 1:

The flow obstacle is positioned at an optimized distance from the nozzle - close enough to effectively modify spray jet geometry but not so close as to cause excessive pressure fluctuations. This partial positioning achieves sufficient geometry control while avoiding the harmful effects of placing the obstacle too near the nozzle exit.

Inventive Principle:
Principle #16Partial or excessive action

3Adaptability or versatility

If multiple flow obstacles are added to different nozzles for customized spray patterns, then adaptability to different cleaning needs is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvespray pattern customizationVSAvoidspray arm assembly
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The spray arm is divided into multiple independent nozzle units, each capable of having its own flow obstacle. This segmentation allows for customized spray patterns at each nozzle position while maintaining a modular structure that simplifies manufacturing and assembly. Each nozzle-obstacle pair can be manufactured and tested independently before final assembly.

Inventive Principle:
Principle #1Segmentation

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 improved cleaning performance by enabling the spray jet to change geometry, effectively reaching difficult areas and increasing the coverage area, while maintaining low influence from pressure fluctuations.

Implementation Method 1

a flow obstacle for changing the geometry of the spray jet is provided within the spray arm in front of at least one nozzle

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentEP2192852B1Dishwasher
Publication Date: 2011.09.14 MIELE & CO KG
  • EP2192852B1 patent drawingFigure 1~2E
  • EP2192852B1 patent drawingFigure 3~4B
  • EP2192852B1 patent drawingFigure 5~6B

AI summary

A dishwasher comprises a rinsing chamber in which is rotatably mounted at least one spray arm (V) on which are provided a plurality of nozzles (5, 6) for spraying rinsing liquid, which nozzles (5, 6) are supplied with rinsing liquid by means of a pump. A flow obstruction (8') for varying the geometry of the spray jet is provided within the spray arm in front of at least one nozzle (5). In this way, the spray pattern at the nozzle can be individually adapted.