Fire-resistant glazing unit with transparent screening layer
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Solution Overview
Problem
Fire-resistant glazings with intumescent alkaline silicate layers face defects such as bubbles and veils due to inadequate composition and exposure to heat or radiation, particularly when in contact with the 'tin' side of glass sheets, leading to optical defects and reduced transparency.
Innovation Solution
A thin, inert screening layer made from materials like titanium dioxide or modified titanium oxide is interposed between the intumescent layer and the glass to prevent interaction, applied via cathode sputtering to maintain transparency and chemical stability, ensuring minimal light transmission reduction and resistance to alkaline environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screening layer is added to prevent interaction between the intumescent layer and the glass, then defect formation is prevented, but light transmission is reduced
Solution Approach 1:
A screening layer made of chemically inert material (such as silicon oxide, titanium oxide, or zinc oxide) is introduced as an intermediary between the intumescent alkaline silicate layer and the glass sheet. This intermediate layer prevents direct harmful interaction while being sufficiently transparent to minimize impact on light transmission, thus resolving the contradiction between defect prevention and optical quality.
2Illumination intensity
If the intumescent layer is made thinner to maintain transparency, then optical quality is improved, but fire resistance is reduced
Solution Approach 1:
The glazing assembly uses a composite structure combining multiple materials: glass sheets, intumescent alkaline silicate layer, and screening layer. This composite approach allows optimization of each layer's thickness and properties to simultaneously achieve good transparency, fire resistance, and defect-free performance.
3Reliability
If multiple intumescent layers are added to improve fire resistance, then fire protection is enhanced, but manufacturing complexity increases
Solution Approach 1:
The protective function is segmented into distinct layers: fire-resistant intumescent layers and defect-preventing screening layers. This segmentation allows each layer to perform its specific function optimally while making the overall manufacturing process more manageable through standardized layer assembly.
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 solution effectively prevents defects and maintains optical quality, with light transmission reduction below 3% and color variation under accelerated aging, ensuring the glazing's fire-resistant and transparent properties are preserved over time.
Implementation Method 1
The method for applying the screen layers is deposition by cathode sputtering under vacuum, advantageously assisted by magnetron.
Data Source
Figure 1~2b
AI summary
The invention relates to a fire-resistant glazing unit comprising several glass sheets separated by layers of intumescent material based on hydrated alkali metal silicate, at least one "tin" face of one of the sheets being in contact with the intumescent material, characterized in that the latter face is coated with an essentially transparent thin layer of a material which withstands contact with the intumescent composition of hydrated alkali metal silicate.