Window Frame Thermal Break Design for Condensation Prevention

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Solution Overview

Problem

In window frames, especially in sliding windows, decorative materials on the indoor side are prone to water condensation when outdoor temperatures are lower, leading to potential water dripping onto insulating connecting members, which can cause early deterioration and compromise the insulating properties.

Innovation Solution

A frame design with an inner, outer, and intermediate lower frame part, where insulating connecting members are interposed between the intermediate and inner, and outer frames, and a support member with drainage features is used to prevent water from reaching the insulating members, ensuring the decorative material remains dry and maintaining insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the decorative material is arranged between the track on the indoor side and the plate member on the outdoor side, then the design is improved, but water condensation occurs on the decorative material when outdoor temperature is lower than indoor temperature

Engineering Contradiction:
ImprovedesignVSAvoidwater condensation
Core Design Contradiction:
ShapeVSObject-affected harmful factors

Solution Approach 1:

An intermediate lower frame part is introduced between the inner lower frame part and the outer lower frame part. This intermediate structure serves as a thermal break, preventing direct thermal transmission from the outdoor side to the indoor decorative material, thereby eliminating the condensation problem while preserving the design.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The lower frame is divided into three separate parts: inner lower frame part, intermediate lower frame part, and outer lower frame part. This segmentation creates thermal breaks that prevent heat transfer, stopping the temperature drop that causes condensation on the decorative material.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the connecting member is arranged on the outdoor side of the track, then the insulating property is improved, but water condensation causes early deterioration of the connecting member

Engineering Contradiction:
Improveinsulating propertyVSAvoidservice life of connecting member
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The intermediate lower frame part acts as a mediator that prevents water condensation from reaching the connecting member. By positioning the connecting member on the outdoor side of the track while using the intermediate frame part as a thermal and moisture barrier, the insulating property is maintained and water damage is prevented.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The intermediate lower frame part is positioned in advance to prevent water condensation from reaching the connecting member before deterioration can occur. This preliminary protective measure ensures the connecting member remains dry and maintains its insulating properties throughout its service life.

Inventive Principle:
Principle #9Preliminary anti-action

3Object-affected harmful factors

If the lower frame is divided into inner, outer, and intermediate parts, then water condensation prevention is improved, but the device complexity increases

Engineering Contradiction:
Improvewater condensation preventionVSAvoidframe structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The intermediate lower frame part combines multiple functions: it serves as a thermal break to prevent condensation, provides structural support, and acts as a mounting surface for the covering member. By merging these functions into a single component, the overall complexity is reduced despite the segmented frame structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The intermediate lower frame part is designed as a multi-functional component that provides thermal insulation, structural support, and mounting capabilities. This universal design approach reduces the need for additional separate components, thereby managing complexity while achieving effective condensation prevention.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design effectively prevents water condensation on decorative materials and reduces the risk of early deterioration of insulating members, while maintaining the insulating properties and improving the external appearance of the window frame.

Implementation Method 1

an inner connecting member having an insulating property is interposed between the intermediate lower frame part and the inner lower frame part, and an outer connecting member having an insulating property is interposed between the intermediate lower frame part and the outer lower frame part

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3530858B1Fitting and method of manufacturing frame member
Publication Date: 2020.06.24 YKK AP INC
  • EP3530858B1 patent drawingFigure 1
  • EP3530858B1 patent drawingFigure 2
  • EP3530858B1 patent drawingFigure 3

AI summary

A lower frame (12) includes an inner lower frame part (40) on which a track (17) is arranged, an outer lower frame part (50) supporting a surface facing an outdoor side of a panel (21), and an intermediate lower frame part (60) positioned between the inner lower frame part (40) and the outer lower frame part (50). A covering member (140) is arranged at a portion closer to an outdoor side of a fitting than a movable sash (30) in the lower frame (12), the covering member (140) including an upper surface part (142) extending toward an indoor side from an upper end of the outer lower frame part (50) to cover a gap between the outer lower frame part (50) and the movable sash (30), and a leg part (141) extending downward from an edge positioned on an indoor side of the upper surface part (142) to be supported by the intermediate lower frame part (60). The intermediate lower frame part (60) and the inner lower frame part (40) are separated from each other and an inner connecting member (90) having an insulating property is interposed therebetween, and the intermediate lower frame part (60) and the outer lower frame part (50) are separated from each other and an outer connecting member (100) having an insulating property is interposed therebetween.