Multi-layered Window Sealing for Condensation Prevention

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Solution Overview

Problem

Multi-layered windows in high-speed railroad cars face issues with condensation between glass and polycarbonate panes due to water permeability and thermal expansion differences, leading to sealer failure and moisture ingress.

Innovation Solution

A multi-layered window structure with a glass pane and a smaller, thinner polycarbonate pane, a hollow annular spacer packed with desiccating agent, and a primary sealer made of isobutylene-isoprene rubber, along with a secondary sealer and black coating film to prevent moisture and thermal stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a polycarbonate window pane is used to prevent breakage from stone impact, then safety and breakage resistance are improved, but water permeability increases causing condensation between panes

Engineering Contradiction:
Improvebreakage resistanceVSAvoidcondensation prevention
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

A desiccating agent is introduced as an intermediary substance between the glass and polycarbonate panes. This agent actively absorbs moisture that permeates through the polycarbonate pane, preventing condensation. The desiccating agent serves as a mediator that addresses the water permeability issue without requiring changes to the polycarbonate pane itself, thus maintaining its breakage resistance while solving the condensation problem.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a sealer is used to make the air layer airtight, then airtightness is improved, but thermal expansion differences cause sealer peeling and cracking

Engineering Contradiction:
Improveair layer airtightnessVSAvoidsealer integrity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention changes the physical parameters of the sealer by specifying minimum thickness (0.5 mm or more) and minimum width (6 mm or more). These parameter changes increase the sealer's elasticity and stress absorption capacity. The thicker and wider sealer can accommodate the thermal expansion differences between glass and polycarbonate without peeling or cracking, maintaining both airtightness and structural integrity under temperature variations.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a thick desiccating agent layer is used to prevent condensation, then dehumidification effectiveness is improved, but space between panes increases reducing insulation performance

Engineering Contradiction:
Improvecondensation preventionVSAvoidthermal insulation
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The desiccating agent is placed locally at the edges of the window panes rather than uniformly distributed across the entire air layer. This localized placement at the periphery allows effective moisture absorption with minimal space occupation, preserving the central air layer thickness for thermal insulation. The edge-specific positioning optimizes both dehumidification functionality and thermal insulation performance.

Inventive Principle:
Principle #3Local quality

4Strength

If a shatterproof film is applied to prevent glass damage from stone impact, then breakage resistance is improved, but it does not completely prevent damage

Engineering Contradiction:
Improveimpact resistanceVSAvoiddamage prevention
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention uses a composite window structure combining glass and polycarbonate panes. The polycarbonate pane serves as the primary impact-resistant layer facing the outside, while the glass pane provides optical clarity inside. This composite material approach leverages the high impact resistance of polycarbonate to protect against stone impacts, eliminating the need for shatterproof films while achieving complete damage prevention.

Inventive Principle:
Principle #40Composite materials

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

Prevents condensation by limiting thermal expansion deformation, maintaining sealer integrity, and dehumidifying the air layer, effectively reducing moisture permeation and sealer deterioration.

Implementation Method 1

a hollow annular spacer disposed so as to extend along edges of the first window pane and the second window pane... The spacer has a hollow annular shape, and is packed with desiccating agent

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

a primary sealer being an elastic body, with a thickness of 0.5 mm or more and a width of 6 mm or more... is disposed between the first window pane and the spacer, and between the second window pane and the spacer

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2597244B1Multi-layered window structure
Publication Date: 2018.10.03 TOHO SHEET & FRAME CO LTD
  • EP2597244B1 patent drawingFigure 1
  • EP2597244B1 patent drawingFigure 2
  • EP2597244B1 patent drawingFigure 3

AI summary

A multi-layered window structure of the present invention includes: a first window pane made of glass; a second window pane made of polycarbonate, being smaller in both height and width than the first window pane, and formed to a thickness of 5 mm to 30 mm; a hollow annular spacer disposed so as to extend along edges of the first window pane and the second window pane, and having holes in a side wall facing an air layer between the first window pane and the second window pane; and a primary sealer being an elastic body, with a thickness of 0.5 mm or more and a width of 6 mm or more, that extends along the edges of the first window pane and the second window pane, and is disposed between the first window pane and the spacer, and between the second window pane and the spacer.