Glass or glass ceramic element comprising glass or glass ceramic substrate and coating and method for its production and its use
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Solution Overview
Problem
Glass or glass ceramic elements used in applications with elevated temperatures often have high surface temperatures on the side facing away from the heat source, leading to potential burns and inefficient heat retention, and existing coatings fail to adequately reduce these temperatures while maintaining mechanical strength and visibility.
Innovation Solution
A glass or glass ceramic element with a transparent substrate and a coating comprising a glass-based enamel coating, including IR-reflecting pigments and fillers with specific thermal properties, such as zirconium oxide and rare earth oxides, to reduce surface temperatures on the side facing away from the heat source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a glass or glass ceramic element is used in applications with elevated temperatures, then the element can withstand high temperature environments, but the surface temperature on the side facing away from the heat source becomes high leading to potential burns
Solution Approach 1:
The patent applies a coating with specific thermal properties (low thermal conductivity and low specific molar heat capacity) to the surface of the glass element. This creates a localized thermal barrier layer that differentiates the thermal behavior of the coated surface from the bulk material, reducing heat transfer to the outer surface while maintaining the overall high-temperature resistance of the glass element.
Solution Approach 2:
The patent uses a composite coating system comprising glass or glass ceramic substrate combined with a specialized coating layer containing pigments and fillers with specific thermal properties. This composite structure combines the high-temperature stability of glass with the thermal insulation properties of the coating materials (such as zirconium oxide, hafnium oxide, and rare earth oxides) to achieve both heat resistance and surface temperature reduction.
2Loss of energy
If the glass element acts as a heat sink allowing heat to escape to the outside, then heat dissipation occurs, but this reduces the efficiency of the combustion process and leads to increased soot formation
Solution Approach 1:
The coating is applied specifically to the outer surface of the glass element to create a localized thermal barrier. This selective surface treatment prevents heat loss to the environment while maintaining the internal combustion process efficiency, as the coating only affects the external heat dissipation pathway rather than the internal heat generation and distribution.
Solution Approach 2:
The coating materials are selected to have thermal expansion coefficients compatible with the glass substrate, ensuring that the coating maintains its integrity and insulating properties under thermal cycling conditions. This prevents coating delamination or cracking that would compromise the thermal barrier function and allow heat loss.
3Temperature
If multiple panes are used to keep the outside of an oven door cool, then surface temperature is reduced, but the device complexity increases
Solution Approach 1:
The patent extracts the thermal insulation function from the bulk glass structure and concentrates it into a specialized surface coating layer. This allows a single-pane construction to achieve the thermal performance previously requiring multiple panes, as the coating contains the critical thermal barrier properties in a thin surface layer rather than requiring thick or multi-layer glass assemblies.
Solution Approach 2:
The patent changes the thermal parameters (thermal conductivity and specific molar heat capacity) of the surface layer through the application of a specialized coating. This parameter modification at the surface level achieves the desired thermal performance without altering the overall structure or requiring additional panes, maintaining simplicity while improving thermal management.
4Strength
If a TCO layer and decorative coating are applied to achieve homogeneous mechanical properties, then mechanical strength is improved, but the TCO layer becomes sensitive to scratches and handling becomes difficult
Solution Approach 1:
The patent uses a composite coating system combining glass matrix with carefully selected pigments and fillers to achieve both mechanical strength and scratch resistance. The glass-based coating provides a hard, durable surface that is resistant to scratching, while the composite structure with appropriate filler materials enhances overall mechanical properties without the sensitivity issues of TCO layers.
Solution Approach 2:
The coating is designed to provide localized protection and property enhancement at the surface level. By concentrating the functional materials (pigments for IR reflection, fillers for mechanical reinforcement) in the surface coating layer, the patent achieves improved mechanical properties and scratch resistance where needed, while keeping the bulk glass material simple and easy to handle.
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 coating effectively reduces surface temperatures on the non-exposed side of the glass or glass ceramic element, enhancing safety and heat retention while maintaining mechanical strength and visibility, even at low temperatures.
Implementation Method 1
The at least one pigment preferably comprises an IR-reflecting material
Implementation Method 2
the pigments of the decorative coating, with a particle size between 500 nm and 10 μm, are so large that the particles can efficiently scatter the heat radiation
Implementation Method 3
the at least one filler is a material with a specific molar heat capacity of at most 5 mJ / (mol K) and preferably a thermal conductivity of at most 12 W/(m K)
Implementation Method 4
specific molar heat capacity of at most 5 mJ / (mol K)
Data Source
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AI summary
The invention relates generally to glass or glass-ceramic elements for household and/or heating appliances, comprising at least one glass or glass-ceramic substrate and a coating arranged at least partially on at least one of the main surfaces. Furthermore, the present invention relates to a method for manufacturing such an element and its use.