Platinum Conduit Ceramic Insulation for Thermal Expansion

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Solution Overview

Problem

In glass manufacturing apparatuses, such as vacuum degassing apparatuses, the difference in thermal expansion between platinum or platinum alloy conduits and ceramic structures leads to cracks, while existing solutions with gaps between conduits and ceramic structures risk conduit deformation and corrosion from molten glass.

Innovation Solution

A method involving a conduit structure with a first ceramic structure around it, where the gap between the conduit and a second ceramic structure is filled with a slurry body containing specific zirconium oxide and silicon dioxide particles, sintered to form a ceramic structure with a coefficient of linear thermal expansion matching that of platinum or platinum alloys, eliminating gaps and enhancing corrosion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If unshaped ceramic material is filled between the conduit and insulating brick to absorb thermal expansion differences, then the conduit can move relatively during temperature changes, but cracks still occur at junctions between vertical and horizontal pipes due to insufficient absorption of thermal expansion

Engineering Contradiction:
Improvecrack preventionVSAvoidthermal expansion matching
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the key parameter of the ceramic material from generic unshaped ceramic to zirconia-based ceramic with specifically controlled thermal expansion coefficient (7-10×10^-6/K) to match the platinum conduit. This parameter optimization enables the ceramic to absorb thermal expansion differences effectively, preventing cracks at pipe junctions while maintaining structural integrity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure consisting of platinum conduit surrounded by zirconia-based ceramic insulating material. This composite design combines the high-temperature resistance of platinum with the thermal expansion compatibility of zirconia ceramic, creating a system that can withstand thermal cycling without cracking.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a gap is provided between the conduit and ceramic structure to absorb thermal expansion timing deviation, then cracks at junctions are prevented, but the conduit may deform due to expansion pressure from molten glass

Engineering Contradiction:
Improvecrack preventionVSAvoidconduit deformation resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the mechanical parameters of the zirconia ceramic, achieving compression strength of 5 MPa or more at 1400°C. This enhanced mechanical property allows the ceramic to provide both gap absorption for thermal expansion and sufficient support to prevent conduit deformation under molten glass pressure.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the ceramic structure is arranged without providing a gap around the conduit to prevent conduit deformation, then expansion pressure from molten glass is resisted, but it becomes difficult to arrange the ceramic structure at junctions between vertical and horizontal pipes

Engineering Contradiction:
Improveconduit deformation resistanceVSAvoidceramic arrangement difficulty
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent specifies that the zirconia-based ceramic should have porosity of 20-60%, making the material more flexible and easier to shape and arrange around complex conduit geometries including junctions between vertical and horizontal pipes, while still maintaining sufficient mechanical strength to prevent conduit deformation.

Inventive Principle:
Principle #31Porous materials

4Reliability

If platinum or platinum alloy is used as the conduit material to ensure heat resistance and corrosion resistance, then the conduit can withstand high temperature and molten glass corrosion, but the difference in thermal expansion coefficient with ceramic materials causes thermal expansion problems

Engineering Contradiction:
Improveheat resistance and corrosion resistanceVSAvoidthermal expansion stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent creates a composite system where platinum conduit (with thermal expansion coefficient of 9-11×10^-6/K) is surrounded by zirconia-based ceramic (with thermal expansion coefficient of 7-10×10^-6/K). The closely matched thermal expansion coefficients of these two materials enable the composite structure to withstand thermal cycling without cracking, while maintaining the excellent heat resistance and corrosion resistance of platinum.

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 cracks and deformation of conduits due to thermal expansion and corrosion from molten glass, ensuring stable and long-term operation of glass manufacturing apparatuses by maintaining the integrity of the ceramic structure.

Implementation Method 1

a method involving a conduit structure with a first ceramic structure around it, where the gap between the conduit and a second ceramic structure is filled with a slurry body containing specific zirconium oxide and silicon dioxide particles, sintered to form a ceramic structure

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 2

a ceramic structure having a coefficient of linear thermal expansion substantially equal to that of platinum or a platinum alloy constituting a conduit for molten glass

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2918554B1Molten glass conveying equipment element, method for manufacturing molten glass conveying equipment element, glass manufacturing apparatus comprising molten glass conveying equipment element and method for manufacturing glass product
Publication Date: 2019.09.11 AGC INC
  • EP2918554B1 patent drawingFigure 1~2
  • EP2918554B1 patent drawingFigure 3
  • EP2918554B1 patent drawingFigure 4~5

AI summary

The present invention provides a molten glass conveying equipment element which has a ceramic structure that achieves prevention of crack generation in a conduit caused by thermal expansion during heating or contraction during cooling as well as prevention of conduit deformation caused by inflation pressure applied by molten glass, and that is not susceptible to erosion even if the molten glass leaks for some reason. The present invention also provides a method for manufacturing the molten glass conveying equipment element and a glass manufacturing apparatus comprising the molten glass conveying equipment element.