Laundry drying appliance comprising at least one finned-tube heat exchanger

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Solution Overview

Problem

Laundry drying appliances with heat exchangers face reduced effectiveness due to moisture condensation and adhesion of fluff and hair on the heat exchange surfaces, which existing cleaning methods and non-stick coatings fail to address effectively and efficiently, especially in cost and environmental terms.

Innovation Solution

A laundry drying appliance featuring a finned-tube heat exchanger with directly mechanically formed submillimetre-scale structures on the metal fins, providing hydrophobic or oleophobic properties through roll-to-roll imprinting, reducing adhesion and enhancing durability and chemical resistance without the need for coatings or curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a non-stick coating is applied to the heat exchange surface, then cleanability is improved, but heat exchange effectiveness is reduced and cost increases

Engineering Contradiction:
ImprovecleanabilityVSAvoidheat exchange effectiveness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces chemical coatings with a mechanically formed submillimetre-scale surface structure. The structured surface provides non-stick properties through physical geometry rather than chemical composition, eliminating the need for coatings while maintaining heat exchange effectiveness and reducing cost.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the surface parameter from smooth to submillimetre-scale structured. This geometric parameter change creates hydrophobic/oleophobic properties that reduce adhesion of fluff and hair, improving cleanability without affecting thermal performance.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a jet or spray of water is used to clean the heat exchange surface, then moisture condensation is removed, but fluff and hair remain and device complexity increases

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidcleaning device complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by forming the submillimetre-scale structure on the heat exchange surface before operation. This pre-structured surface passively prevents adhesion of fluff and hair, eliminating the need for active cleaning devices and simplifying the overall system.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The structured surface provides self-cleaning properties by preventing adhesion in the first place. The surface structure causes fluff and hair to slide off rather than stick, making the system self-maintaining without requiring external cleaning devices.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If the heat exchange surface is left untreated, then cost is reduced, but adhesion of fluff and hair increases and heat exchange effectiveness decreases

Engineering Contradiction:
Improvemanufacturing costVSAvoidheat exchange effectiveness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a mechanically formed surface structure instead of chemical coatings or complex cleaning systems. This approach maintains cost-effectiveness while solving the adhesion problem, as the structure can be formed during manufacturing without additional material or system costs.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The submillimetre-scale structure improves heat exchange effectiveness by minimizing fluff and hair adhesion, reducing cleaning needs, and offering a cost-effective and environmentally friendly solution with enhanced durability and chemical resistance.

Implementation Method 1

providing hydrophobic or oleophobic properties through roll-to-roll imprinting, reducing adhesion

Methodology Applied
Scientific EffectHydrophobic effect: Hydrophobe

Implementation Method 2

providing hydrophobic or oleophobic properties through roll-to-roll imprinting, reducing adhesion

Methodology Applied
Scientific EffectOleophobic effect: Hydrophobe

Implementation Method 3

heat exchangers to cool down and/or heat up process air flowing in a process air channel

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 4

While moisture will condensate and mostly drops down into a condensate tub or container

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3382315B1Laundry drying appliance comprising at least one finned-tube heat exchanger
Publication Date: 2019.11.20 BSH HAUSGERATE GMBH
  • EP3382315B1 patent drawingFigure 1~2
  • EP3382315B1 patent drawingFigure 3~4

AI summary

A household appliance (12) according to the invention comprises at least one metal component (14, 16) having a treated surface (17, 18) wherein the treated surface (17, 18) comprises a directly mechanically formed submillimetre-scale structure (6). A method (S1) according to the invention for treating a surface (17, 18) of a metal component (14, 16) of a household appliance (12) wherein the surface (17, 18) is treated by directly mechanically forming a submillimetre-scale structure (6) on the metal surface (17, 18). The invention is particularly useful for laundry treatment appliances, in particular laundry dryers, in particular comprising a heat pump.