Outer Tub Coating to Reduce Foam Formation in Washing Machines

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Solution Overview

Problem

Foam formation in household appliances like washing machines degrades washing performance, affects flushing efficiency, and leads to water consumption and time inefficiencies, with existing procedural measures being environmentally and customer-unfriendly.

Innovation Solution

A household appliance component with a coating that reduces surface energy to inhibit foam formation, using materials like silicone oil and polydimethylsiloxane to prevent foam formation and dissolution of existing foam, acting as a defoamer by reducing surface tension below that of the foam.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If process engineering measures are used to remove foam generated during washing, spinning, or pumping, then foam is removed, but water and time consumption increase

Engineering Contradiction:
ImprovefoamVSAvoidwater consumption
Core Design Contradiction:
Object-generated harmful factorsVSLoss of substance

Solution Approach 1:

The coating is applied in advance to the component surface before foam formation occurs. The coating creates a hydrophobic barrier that prevents foam from adhering to the surface, thereby preemptively counteracting the harmful effects of foam without requiring additional water or time during the washing process.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The invention converts the harmful property of foam (which normally increases water consumption for removal) into a beneficial effect by using the foam's own surface tension properties. The hydrophobic coating exploits the fact that foam cannot adhere to low-energy surfaces, thereby eliminating foam problems without the need for additional water or chemical foam inhibitors.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Object-generated harmful factors

If process engineering measures are used to remove foam, then foam is removed, but time consumption increases

Engineering Contradiction:
ImprovefoamVSAvoidtime consumption
Core Design Contradiction:
Object-generated harmful factorsVSLoss of time

Solution Approach 1:

The coating is applied in advance to the component surface before foam formation occurs. The coating creates a hydrophobic barrier that prevents foam from adhering to the surface, thereby preemptively counteracting the harmful effects of foam without requiring additional time during the washing process.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The invention converts the harmful property of foam into a beneficial effect by using the foam's own surface tension properties. The hydrophobic coating exploits the fact that foam cannot adhere to low-energy surfaces, thereby eliminating foam problems without the need for additional time or process steps.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Object-generated harmful factors

If soluble foam inhibitors are used in the washing solution, then foam is reduced, but the need for additional chemicals increases

Engineering Contradiction:
ImprovefoamVSAvoidchemical usage
Core Design Contradiction:
Object-generated harmful factorsVSQuantity of substance

Solution Approach 1:

The invention extracts the foam-inhibiting function from the washing solution and relocates it to the component surface coating. Instead of adding chemical foam inhibitors to the water, the hydrophobic coating is applied directly to the component, thereby eliminating the need for additional chemicals in the washing solution while still achieving foam reduction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The hydrophobic coating acts as an intermediary between the foam and the component surface. Rather than using chemical foam inhibitors that mix with the washing solution, the coating serves as a physical barrier that prevents foam adhesion through its low surface energy properties, thereby reducing chemical usage.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Object-generated harmful factors

If foam forms in the appliance, then washing solution is affected, but washing performance deteriorates

Engineering Contradiction:
ImprovefoamVSAvoidwashing performance
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The coating is applied in advance to prevent foam from forming and adhering to component surfaces during the washing process. By creating a hydrophobic barrier before foam generation occurs, the coating maintains washing solution effectiveness and preserves mechanical action between laundry items throughout the cycle.

Inventive Principle:
Principle #9Preliminary anti-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

Eliminates the need for soluble foam inhibitors, reduces foam formation and size, enhancing washing efficiency, reducing water consumption, and preventing foam escape, thereby improving appliance performance and environmental sustainability.

Implementation Method 1

the component has a coating for reducing the surface energy of a contact surface of the component with the washing solution

Methodology Applied
Scientific EffectSurface energy reduction: Surface Tension

Implementation Method 2

The coating is a foam inhibitor. This achieves, for example, the technical advantage that soluble foam inhibitors in the washing solution can be dispensed with and foam in the component can be dissolved quickly

Methodology Applied
Scientific EffectFoam inhibition: Antifoam

Implementation Method 3

The foam bubbles are successfully destroyed and/or reduced in size when the surface tension of an insoluble material in the coating that comes into contact with the foam is lower than the surface tension of the foam itself

Methodology Applied
Scientific EffectSurface tension reduction: Surface Tension

Data Source

PatentEP3152354B1Household appliance comprising an outer tub
Publication Date: 2019.07.24 BSH HAUSGERATE GMBH
  • EP3152354B1 patent drawingFigure 1
  • EP3152354B1 patent drawingFigure 2
  • EP3152354B1 patent drawingFigure 3

AI summary

The present invention relates to a household appliance (100) comprising a component (101) for carrying or accommodating washing lye (107), the component (101) having a coating (103) for reducing the surface energy of a contact surface (105) of the component (101) with the washing lye (107).