Precious-Metal Glass Heating to Reduce Bubbles and Particles

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Solution Overview

Problem

Existing glass manufacturing methods using direct and indirect heating systems result in defects such as bubbles and particles due to electrochemical reactions and heat conduction delays, particularly in the transport of molten glass, which are critical for high-quality thin glass products.

Innovation Solution

A method for manufacturing glass products with reduced defects by controlling the phase angle between current and voltage during the heating process, using a conductor system with precious metals to minimize electrochemical reactions and bubble/particle formation, and optimizing the current flow to reduce stress on the precious metal components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If direct heating by passing current through the glass or heating the pipe walls through resistance heating is used, then the glass can be heated effectively to maintain viscosity for transport, but electrochemical reactions occur leading to bubble formation and particle defects

Engineering Contradiction:
Improveglass temperatureVSAvoidbubble and particle defects
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary heating system where heating elements are positioned in the molten glass without direct electrical contact. The heating elements convert electrical energy to thermal energy through resistance heating, which then transfers to the glass through thermal conduction. This intermediary approach avoids direct electrochemical reactions between electricity and glass while maintaining effective heating.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the direct electrical heating mechanism (which causes electrochemical reactions) with a thermal conduction-based heating system. Instead of passing current directly through the glass or using resistance heating of pipe walls, the system uses heating elements that transfer thermal energy to the molten glass, substituting electrical-mechanical interaction with thermal-mechanical interaction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If indirect heating systems using belt heaters or radiant heaters are used, then electrochemical reactions are avoided, but heat conduction delays temperature control and reduces heating efficiency

Engineering Contradiction:
Improveelectrochemical reactionsVSAvoidheat conduction delay
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The heating elements act as intermediaries that are directly immersed in the molten glass, enabling efficient thermal conduction without causing electrochemical reactions. The elements convert electrical energy to thermal energy and transfer it directly to the glass through thermal conduction, eliminating the time delays associated with indirect heating methods while avoiding harmful electrochemical reactions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the heating parameter from indirect thermal radiation or convection to direct thermal conduction through immersed heating elements. This parameter change in the heating mechanism allows for more efficient heat transfer to the molten glass while maintaining the advantage of avoiding electrochemical reactions that occur with direct electrical contact methods.

Inventive Principle:
Principle #35Parameter changes

3Power

If high current density is applied for efficient heating, then heating efficiency increases, but stress on precious metal components increases leading to potential failure

Engineering Contradiction:
Improveheating powerVSAvoidcomponent durability
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

The heating elements serve as intermediaries that convert electrical power to thermal power before transferring heat to the glass. This allows for efficient heating with high power input while the thermal conduction mechanism distributes the thermal load evenly, preventing localized stress concentrations that would occur with direct electrical heating and thereby protecting the structural integrity of precious metal components.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the heating parameter from direct electrical current application to thermal conduction-based heating. This parameter change allows for high heating power to be applied efficiently while the thermal nature of the heating process distributes energy more uniformly, reducing peak stresses on components and improving overall system durability.

Inventive Principle:
Principle #35Parameter changes

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 method produces glass products with significantly lower particle and bubble counts, ensuring high product quality and reducing the need for aggressive refining agents, thereby enhancing the stability and durability of precious metal components.

Implementation Method 1

the conductor system comprising the precious metal is current-carrying in such a way that Joule heating is generated in the conductor system comprising the precious metal

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3932875B1Method of making a glass product
Publication Date: 2026.01.28 SCHOTT AG
  • EP3932875B1 patent drawingFigure 1~2c
  • EP3932875B1 patent drawingFigure 3a~3c
  • EP3932875B1 patent drawingFigure 4~7

AI summary

The invention relates to a method for producing a glass product, preferably a disc-shaped glass product, wherein a silicate glass melt is transferred through a conductor system comprising a precious metal from one region of an aggregate for producing a glass product to another region of the aggregate for producing a glass product, and wherein the conductor system comprising the precious metal is current-carrying in such a way that Joule heating is generated in the conductor system comprising the precious metal, in particular in the precious metal, by an electric current passed through the precious metal, characterized in that the current is an alternating current in which the time integral over a positive and a negative half-wave is essentially zero, and comprises a glass product, preferably a disc-shaped glass product, which is produced or can be produced by the method.