Steam Generator Surface Structure for Scale Flaking and Water Spreading
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Solution Overview
Problem
Conventional steam generators for garment care devices face issues such as water pooling, scale build-up, and film boiling due to high temperatures, which compromise steam generation efficiency and lead to coating delamination.
Innovation Solution
A steam generator design featuring a steaming surface with spatially separated protrusions of truncated and pyramidal shapes to promote scale flaking, reduce coating delamination, and enhance water spreading, combined with a hydrophilic and porous steam promoter coating to suppress film boiling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the steaming surface length is shortened to make the steam generator more compact, then the device size is reduced, but water pooling occurs at the bottom of the steaming surface
Solution Approach 1:
The steaming surface is divided into multiple zones with different protrusion densities. The first zone (proximal to water inlet) has a first density of protrusions, while the second zone (distal to water inlet) has a second density of protrusions that is lower than the first density. This segmentation allows different regions to perform different functions: the first zone promotes water spreading and prevents pooling, while the second zone allows controlled water flow.
Solution Approach 2:
Different regions of the steaming surface are given different local properties through varying protrusion densities. The first zone has higher protrusion density to enhance water distribution and prevent pooling, while the second zone has lower protrusion density to allow efficient water flow and steam generation. This local quality variation resolves the contradiction between compact size and water pooling prevention.
2Productivity
If the steaming surface temperature is increased to improve steam generation, then steam production efficiency is enhanced, but film boiling occurs on the steaming surface
Solution Approach 1:
The steaming surface is provided with an array of protrusions that create a porous or textured surface structure. This porous structure increases the surface area for water contact and promotes capillary action, allowing water to be drawn closer to the heated surface without forming a insulating vapor film. The protrusions create micro-channels that facilitate continuous water supply to the heating elements, preventing film boiling while maintaining high steam generation efficiency.
3Productivity
If a steam promoter coating is applied to the steaming surface to prevent film boiling, then steam generation is improved, but the coating delaminates during use
Solution Approach 1:
Instead of applying a continuous coating that is prone to delamination, the invention uses discrete protrusions segmented across the steaming surface. These protrusions are inherently resistant to delamination as they are structural features rather than surface coatings. The protrusions perform the steam promotion function through their geometric configuration and surface area effects, eliminating the adhesion problems associated with coatings.
Solution Approach 2:
The invention replaces the steam promoter coating with a structural copy or alternative implementation. Rather than relying on a chemical coating layer, the protrusions provide the same steam promotion functionality through their physical geometry and surface characteristics. This structural approach achieves the desired steam generation enhancement without the reliability issues of coating delamination.
4Volume of moving object
If the steaming surface area is reduced to compact the device, then device footprint is minimized, but scale build-up reduces steam generation capability
Solution Approach 1:
The array of protrusions creates a porous-like structure on the steaming surface that increases the effective surface area for steam generation within a compact footprint. The protrusions provide multiple surfaces for water contact and vaporization, effectively increasing the active steaming area without increasing the overall device size. This porous structure also facilitates scale prevention by disrupting scale formation patterns.
Solution Approach 2:
The invention transitions from a flat two-dimensional steaming surface to a three-dimensional structure with protrusions. This dimensional change increases the surface area available for steam generation within the same footprint, allowing compact device design while maintaining or enhancing steam generation capability. The vertical dimension provided by protrusions adds functional surface area without increasing horizontal footprint.
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 design improves steam generation efficiency by reducing scale build-up, minimizing water pooling, and prolonging instantaneous steam production while maintaining coating adhesion, thus maintaining heat transfer efficiency.
Implementation Method 1
the steaming surface comprises a first portion proximal to the water inlet, and a second portion extending from the first portion in said first direction
Implementation Method 2
Orientation of the protrusions in this manner may assist lateral/transverse water spreading on the steaming surface
Implementation Method 3
Such high temperatures can result in film boiling of water on the steaming surface, also known as the Leidenfrost effect. This can compromise the capability of the steam generator to generate steam instantaneously. Whilst the Leidenfrost effect can be mitigated via a steam promoter coating being applied to the steaming surface.
Implementation Method 4
combined with a hydrophilic and porous steam promoter coating to suppress film boiling
Implementation Method 5
Steam generators vaporise water to generate steam
Implementation Method 6
the adhered scale making heat transfer from the steaming surface to the water thereon less efficient
Data Source
Figure 1A~1B
Figure 2A~3
Figure 4A~5B
AI summary
The invention relates to a steam generator (120) for a garment care device. The steam generator comprises a steam generator body (122) comprising a steaming surface (124). An arrangement of spatially separated protrusions (126) project away from the steaming surface. A water inlet (128) is arranged to supply water towards the steaming surface. The steaming surface (124) extends away from the water inlet (128) in a first direction (D1). The steaming surface (124) comprises a first portion (124A) proximal to the water inlet, and a second portion (124B) extending from the first portion in the first direction. The arrangement of spatially separated protrusions comprises a first sub-arrangement of protrusions (126A) projecting from the first portion, with each of the protrusions of the first sub-arrangement having a truncated pyramidal shape. The arrangement of spatially separated protrusions further comprises a second sub-arrangement of protrusions (126B) projecting from the second portion, with each of the protrusions of the second sub-arrangement having a pyramidal shape.