Boiler for a household appliance

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Solution Overview

Problem

The existing boiler designs for household appliances, such as ironing appliances, suffer from inefficient heat transfer between the heating device and the steam generating vessel due to manufacturing tolerances and compression defects in the flexible interface part, leading to reduced energy efficiency.

Innovation Solution

The boiler incorporates thermally conductive interface parts with protuberances on the heat exchange and/or heating surfaces, which compress and penetrate the interface part, increasing contact surface area and reducing the distance between the heating device and steam generating vessel, ensuring effective heat transfer even in weakly compressed zones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a flexible interface part is compressed between the heating surface and heat exchange surface, then heat transfer is promoted, but manufacturing tolerances cause non-negligible portions of the interface part to not contact or be compressed, limiting heat transfer efficiency

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidcontact and compression uniformity
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The heating surface is designed with convex protuberances that protrude toward the flexible interface part. These curved/rounded protuberances increase the contact area with the flexible interface part even when compressed, ensuring reliable thermal contact despite manufacturing tolerances in the flatness of the heating surface and heat exchange surface.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

Instead of requiring the entire heating surface and heat exchange surface to be perfectly flat and parallel, the invention introduces localized protuberances on the heating surface that create concentrated contact points. This local quality approach ensures sufficient thermal contact in critical areas while tolerating variations in other regions.

Inventive Principle:
Principle #3Local quality

2Reliability

If the heating surface and heat exchange surface are assembled by compression, then the steam generating tank is fixed to the heating device, but manufacturing tolerances result in clearance zones where no heat transfer occurs

Engineering Contradiction:
Improvethermal contact reliabilityVSAvoidflatness tolerance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The convex protuberances on the heating surface provide localized contact points that penetrate or compress the flexible interface part effectively. The curved geometry of these protuberances ensures consistent contact pressure and thermal coupling even when the overall assembly has clearance zones due to flatness tolerances.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the heating surface by adding protuberances with specific dimensions (height, diameter, spacing). This parameter modification ensures that despite variations in compression force and flatness tolerance, the protuberances maintain adequate contact pressure and thermal contact area with the flexible interface part.

Inventive Principle:
Principle #35Parameter changes

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 configuration significantly enhances energy efficiency by increasing the contact surface and maintaining thermal contact, resulting in a more efficient boiler compared to prior art designs.

Implementation Method 1

a heating element configured to heat the heating surface

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the interface part being thermally conductive and being compressed between the heating surface and the heat exchange surface

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3502583B1Boiler for a household appliance
Publication Date: 2020.06.24 SEB SA
  • EP3502583B1 patent drawingFigure 1~2
  • EP3502583B1 patent drawingFigure 3~5
  • EP3502583B1 patent drawingFigure 6

AI summary

The boiler (2) comprises a heating device (3) including a heating surface (5), and a heating element configured to heat the heating surface (5); a steam-generating vessel (7) including a bottom (9) provided with a heat exchange surface, the steam-generating vessel (7) being attached to the heating device (3); and an interface piece (19) disposed and compressed between the heating surface (5) and the heat exchange surface, the interface piece (19) being thermally conductive and intended to facilitate heat transfer between the heating device (3) and the steam-generating vessel (7). The heat exchange surface and/or the heating surface (5) has protrusions (24) compressing at least partially the interface piece (19) and penetrating the thickness of the interface piece (19).