Ceramic-Coated Glass Fiber Bushing Nozzles

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Solution Overview

Problem

Homogeneous glass fiber production is hindered by irregular phenomena such as turbulence and foreign matter generation during long-term operation of glass fiber spinning devices, primarily due to platinum volatilization and high-speed air flow affecting nozzle integrity.

Innovation Solution

A ceramic coating layer is applied to the nozzle surfaces of the bushing plate, covering at least the outermost row of nozzles, with specific dimensions to minimize platinum volatilization and abrasion, while leaving the nozzle tip and end face uncoated to prevent molten glass contact and ensure proper glass discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a precious metal nozzle is used, then high-temperature strength and chemical stability are improved, but platinum volatilization causes nozzle abrasion and foreign matter generation

Engineering Contradiction:
Improvehigh-temperature strengthVSAvoidplatinum volatilization
Core Design Contradiction:
StrengthVSLoss of substance

Solution Approach 1:

A ceramic coating layer is applied to the nozzle surface to serve as an intermediary barrier between the precious metal substrate and the molten glass environment. This coating layer suppresses platinum volatilization by preventing direct exposure of the precious metal to the high-temperature glass melt, while allowing the underlying precious metal to maintain its high-temperature strength properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The nozzle is constructed as a composite structure combining a precious metal base material with a ceramic coating layer. This composite design leverages the high-temperature strength of the precious metal while the ceramic coating provides resistance to volatilization and chemical corrosion, creating a material system that exhibits properties superior to either component alone.

Inventive Principle:
Principle #40Composite materials

2Loss of substance

If the entire nozzle is coated with ceramic, then platinum volatilization is suppressed, but molten glass contact with coating causes discharge problems

Engineering Contradiction:
Improveplatinum volatilization suppressionVSAvoidglass discharge stability
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The ceramic coating is applied selectively to specific regions of the nozzle rather than covering the entire surface. The coating is applied to the upper portion and lateral surface where platinum volatilization occurs, while deliberately leaving the tip portion and end face uncoated to ensure proper molten glass contact and discharge. This localized coating strategy addresses volatilization suppression without compromising discharge reliability.

Inventive Principle:
Principle #3Local quality

3Loss of substance

If coating length is increased, then platinum protection is improved, but glass flow irregularity increases

Engineering Contradiction:
Improveplatinum loss reductionVSAvoidglass flow stability
Core Design Contradiction:
Loss of substanceVSStability of the object's composition

Solution Approach 1:

The coating length is optimized to a specific parameter range (50-90% of the total nozzle length from the tip) to balance two competing requirements: sufficient coating coverage to suppress platinum volatilization while maintaining enough uncoated tip area to ensure stable glass flow. This parameter optimization resolves the contradiction by identifying the precise coating length threshold where both protection and flow stability are achieved.

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 ceramic coating suppresses platinum volatilization and abrasion, stabilizing glass flow and preventing foreign matter contamination, enabling long-term stable production of uniform glass fibers with reduced fiber breakage and count variation.

Implementation Method 1

the phenomenon of volatilization loss of platinum on a nozzle surface... the ceramic coating suppresses platinum volatilization and abrasion

Methodology Applied
Scientific EffectVolatilization suppression: Evaporation

Implementation Method 2

a high-speed air flow is generated in a certain direction around the nozzle that ejects the high-temperature fluid at such a high speed. In addition, from the observation results by the present inventors, the high-speed air flow transports platinum volatilized from the nozzle to the vicinity of a base plate

Methodology Applied
Scientific EffectHigh-speed air flow transport: Convection

Implementation Method 3

the volatilized platinum transported to the vicinity of the base plate is cooled and becomes minute lumps of platinum, and the minute lumps adhere onto a surface of the base plate

Methodology Applied
Scientific EffectCooling and condensation: Condensation

Data Source

PatentEP3848335B1Bushing for producing glass fibers
Publication Date: 2023.11.08 TANAKA KIKINZOKU KOGYO KK
  • EP3848335B1 patent drawingFigure 1~2
  • EP3848335B1 patent drawingFigure 3~4
  • EP3848335B1 patent drawingFigure 5~6

AI summary

The present invention relates to a bushing for producing glass fibers, including: a base plate; and multiple nozzles from which molten glass is discharged, in which a nozzle group formed with the alignment of the multiple nozzles is joined to the base plate. In the present invention, a coating layer made of ceramics is formed on each of the nozzles forming at least a row of the outermost layer of the nozzle group. The coating layer does not cover the entire nozzle, that is, the nozzle is covered so as to be in a state of no coating layer in the vicinity of the nozzle tip. The present invention is a bushing plate for producing glass fibers, with which the occurrence of irregular phenomena is suppressed and a uniform glass flow can be obtained stably over a long period of time.