Dishwasher Spray Distribution Control for Foam Suppression

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Solution Overview

Problem

Dishwashers face challenges in reducing foam formation during operation, which leads to reduced delivery pressure and flushing capacity, affecting cleaning performance and increasing energy and water consumption.

Innovation Solution

A dishwasher with at least two spray devices and a distribution unit controlled by a detection system that adjusts the volume flow of washing liquid to suppress foam formation by switching between different spray devices, reducing the tendency for foam to form and allowing existing foam to break down.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the volume flow of washing liquid is increased to improve cleaning performance, then the flushing capacity is improved, but foam formation is promoted which ultimately reduces delivery pressure and flushing capacity

Engineering Contradiction:
Improveflushing capacityVSAvoidfoam formation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system dynamically adjusts the distribution of washing liquid among spray devices based on real-time foam detection. When foam is detected, the control unit redirects water flow from lower-rack spray devices to upper-rack or ceiling spray devices, creating a dynamic response that adapts washing conditions to current foam levels while maintaining cleaning effectiveness.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the distribution parameter of washing liquid volume flow to different spray devices based on foam detection. By altering which spray devices receive water flow and at what rates, the system modifies washing characteristics to suppress foam while preserving cleaning performance through optimized liquid distribution patterns.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If foam formation is suppressed by reducing volume flow or changing spray device distribution, then foam tendency is reduced, but cleaning performance may be compromised

Engineering Contradiction:
Improvefoam formationVSAvoidcleaning performance
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The system employs dynamic switching between different spray device configurations based on real-time foam detection. When foam is detected, the distribution is temporarily adjusted to suppress foam; when foam subsides, the distribution returns to optimize cleaning. This dynamic adaptation ensures cleaning performance is maintained while suppressing foam formation during critical periods.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention implements periodic adjustments to spray device distribution in response to foam detection cycles. The system monitors foam levels continuously and periodically redirects water flow to different spray devices, creating alternating phases of foam suppression and optimized cleaning that maintain overall cleaning performance while preventing excessive foam accumulation.

Inventive Principle:
Principle #19Periodic action

3Object-generated harmful factors

If a detection device and control system are added to suppress foam formation, then foam tendency is reduced, but device complexity increases

Engineering Contradiction:
Improvefoam formationVSAvoidsystem complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The system incorporates a foam detection device that provides real-time feedback to the control unit about foam formation in the washing liquid. This feedback loop enables automatic adjustment of water distribution to spray devices, creating a closed-loop control system that suppresses foam formation through responsive, automated decision-making based on actual foam conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention enables the washing system to self-regulate foam formation through automated detection and control. The foam detection device monitors conditions and the control unit automatically adjusts spray device distribution without requiring manual intervention, allowing the system to service itself by detecting and correcting foam problems in real-time.

Inventive Principle:
Principle #25Self-service

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

Effectively suppresses foam formation while maintaining optimal cleaning performance, reducing energy and water consumption by adjusting the distribution of washing liquid based on detected foam levels, ensuring consistent delivery pressure and capacity.

Implementation Method 1

a pump, in particular a circulating pump, for conveying washing liquid to the spray devices

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

at least two spray devices arranged inside the washing compartment for applying washing liquid to the items to be washed

Methodology Applied
Scientific EffectSpray: Spray

Data Source

PatentEP2701571B1Dishwasher and method for operating a dishwasher
Publication Date: 2015.01.21 BSH HAUSGERATE GMBH
  • EP2701571B1 patent drawingFigure 1
  • EP2701571B1 patent drawingFigure 2~3

AI summary

A dishwasher comprises a dishwashing compartment (1), at least two spray apparatuses (7, 8, 9) which are arranged inside the dishwashing compartment (1), a pump (13) for delivering dishwashing liquid to the spray apparatuses (7, 8, 9), a distributor unit (15) for distributing the dishwashing liquid to the spray apparatuses (7, 8, 9), wherein a volumetric flow rate of the dishwashing liquid is set in dependence on the distribution of the dishwashing liquid to the spray apparatuses (7, 8, 9). A control unit (17) for controlling the distributor unit (15) and a detection device (27) for detecting the formation of foam in the dishwashing liquid are also provided. When the formation of foam in the dishwashing liquid is detected, the distributor unit (15) is actuated in such a way that a volumetric flow rate of the dishwashing liquid is set which is lower than the current volumetric flow rate.