Forehearth Exchangeable Support Blocks for Glass Fibre Manufacturing

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Solution Overview

Problem

Existing glass fibre manufacturing plants face challenges in exchanging support blocks within the forehearth at service temperatures above 1000°C without interrupting production, as the thermal expansion of refractory masonry reduces the gap size, making it difficult to remove and replace blocks like burner blocks, measurement devices, and other equipment without cooling the forehearth or dismantling the masonry.

Innovation Solution

The design incorporates refractory masonry with spacer bricks and a lintel that resist thermal expansion, allowing for reversible insertion and removal of support blocks at high temperatures by maintaining a predetermined gap width, filled with a resilient material to ensure sealing and facilitate easy exchange of blocks like burner blocks, measurement blocks, and other equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If support blocks are integrated into the masonry during forehearth construction, then structural stability and thermal control are improved, but the ability to exchange blocks without interrupting production deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidexchangeability of support blocks
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The forehearth masonry is segmented into modular sections with replaceable support blocks. Each support block is a discrete unit that can be independently removed and replaced without affecting the entire structure, enabling maintenance and exchanges during operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The masonry structure incorporates dynamic elements such as expansion joints and flexible sealing mechanisms that allow for thermal expansion and contraction. This dynamic design permits block exchange without requiring complete structural disassembly or cooling of the entire forehearth.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the forehearth is cooled to remove support blocks, then ease of block removal is improved, but production interruption time increases

Engineering Contradiction:
Improveease of block removalVSAvoidproduction interruption time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent changes the physical parameters of the support blocks and surrounding masonry to maintain removable characteristics at high temperatures. This includes using materials with matched thermal expansion coefficients and designing gap dimensions that remain sufficient for block removal even when thermally expanded.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Resilient sealing materials act as intermediaries between the support blocks and masonry structure. These materials maintain sealing effectiveness while allowing for block insertion and removal without requiring the entire system to be cooled, thus reducing production interruption time.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of repair

If the masonry is dismantled to replace support blocks, then complete block exchange is achieved, but structural integrity and production downtime are adversely affected

Engineering Contradiction:
Improveblock replaceabilityVSAvoidstructural integrity
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The masonry is designed as an assembly of discrete, standardized blocks with uniform dimensions and connection features. This segmentation allows individual support blocks to be replaced without dismantling surrounding structural elements, maintaining overall structural integrity while enabling easy block exchange.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support blocks and surrounding masonry are designed with universal features such as standardized gaps, uniform sealing mechanisms, and compatible material properties. This universality allows any support block to be replaced with another of the same type without requiring custom dismantling procedures, preserving structural integrity while facilitating maintenance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Stability of the object's composition

If thermal expansion of masonry is allowed, then natural thermal response is maintained, but gap size reduces making block removal difficult

Engineering Contradiction:
Improvethermal response stabilityVSAvoidblock removal ease
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent explicitly accounts for thermal expansion by designing the initial gap dimensions between support blocks and masonry to be sufficiently large at room temperature. This ensures that even after thermal expansion reduces the gap size, sufficient clearance remains to facilitate block removal and insertion during high-temperature operation.

Inventive Principle:
Principle #37Thermal expansion

Solution Approach 2:

The design parameters of the masonry structure, particularly gap dimensions and material thermal expansion coefficients, are carefully selected and controlled. By changing and optimizing these parameters during the design phase, the system maintains both thermal response stability and operational ease throughout the temperature range.

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

This solution enables the exchange of support blocks at service temperature without cooling the forehearth or dismantling the masonry, reducing production interruption to less than a day, compared to the typical week-long interruption in previous methods, while maintaining optimal equipment positioning and thermal control.

Implementation Method 1

The gap is filled with a resilient material to ensure sealing and facilitate easy exchange of blocks

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The design incorporates refractory masonry with spacer bricks and a lintel that resist thermal expansion, allowing for reversible insertion and removal of support blocks at high temperatures by maintaining a predetermined gap width

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3419937B1Forehearth comprising exchangeable support blocks
Publication Date: 2019.10.23 3B FIBERGLASS SPRL
  • EP3419937B1 patent drawingFigure 1(a)~1(b)
  • EP3419937B1 patent drawingFigure 2(a)~2(b)
  • EP3419937B1 patent drawingFigure 3(a)~3(b)

AI summary

The present invention concerns a glass fibre manufacturing plant comprising a forehearth forming a passage for conveying molten glass and defined by a first and second opposite longitudinal walls, wherein each longitudinal wall is made of a refractory masonry comprising a cavity of width, Wc, and height, H1c, formed by a floor defined by a base wall, by lateral walls defined by two spacer bricks and by a ceiling defined by a lintel resting on each of the two spacer bricks, and further comprising a support block (20) comprising a hot cuboid portion of width, w, and height, h, wherein w < Wc, and h < H1c, said hot cuboid portion being reversibly inserted in the cavity, thus defining a gap surrounding the hot cuboid portion of the support block when positioned in the cavity, said gap being filled with a resilient material (29), said forehearth being characterized in that, the masonry comprises a spacing element hindering the thermal expansion of the two spacer bricks, such that the distance, Wc, between said two spacer bricks measured at room temperature cannot be reduced below a predetermined hot cavity width, W, at said service temperature, hT, wherein said predetermined distance, W, is larger than the width, w, of the hot cuboid portion of the support block.