Oxy-burner Cooling Unit for Glass Fibre Forehearth

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Solution Overview

Problem

Oxy-burners in glass fibre manufacturing forehearths are prone to thermal degradation due to higher flame temperatures and lower oxygen and fuel flow rates, leading to irreversible damage and reduced service life, especially when oxygen and fuel flow cease, causing the burner tip to overheat.

Innovation Solution

A cooling unit with a thermally conductive cooling plate and annular cavity surrounding the oxy-burner's downstream end, connected to both inlet and outlet for fluid communication, maintains the oxy-burner's temperature below safety thresholds by circulating a refrigerating fluid, preventing overheating and carbon deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If oxy-burners are used to heat the forehearth, then energy efficiency is improved, but the burner tip temperature exceeds safety thresholds causing thermal degradation

Engineering Contradiction:
Improveenergy efficiencyVSAvoidburner tip temperature
Core Design Contradiction:
Use of energy by moving objectVSTemperature

Solution Approach 1:

The burner system is segmented into a heating function (oxy-burner flame) and a cooling function (separate cooling channels). The cooling channels are integrated into the burner block structure, allowing independent control of heating and cooling processes. This segmentation enables the burner to efficiently heat the forehearth while simultaneously protecting the burner tip from overheating through dedicated cooling passages.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Cooling channels are strategically positioned at critical locations within the burner block, particularly near the burner tip and in areas experiencing highest thermal loads. The cooling fluid flow rate and temperature are optimized for each local region to maintain burner components below safety threshold temperatures while allowing the flame zone to reach high temperatures for efficient heating.

Inventive Principle:
Principle #3Local quality

2Use of energy by moving object

If oxygen and fuel flow rates are reduced in oxy-burners, then energy efficiency is improved, but carbon deposition increases due to lower combustion completeness

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcarbon deposition
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The combustion parameters (oxygen and fuel flow rates, mixture ratio, pressure) are precisely controlled and optimized to maintain complete combustion at lower flow rates. The cooling system allows operation at reduced flow rates without thermal degradation, enabling parameter optimization to prevent carbon deposition while maintaining energy efficiency. The cooling channels provide a safety margin that allows operating point adjustment without compromising burner integrity.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If conventional air-burners are replaced by oxy-burners, then productivity is improved, but burner reliability decreases due to thermal degradation

Engineering Contradiction:
Improveforehearth heating efficiencyVSAvoidburner service life
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Cooling channels are pre-integrated into the burner block structure before the burner is installed in the forehearth. The cooling system is designed and positioned in advance to protect critical components from the high temperatures generated during oxy-burner operation. This preliminary integration ensures that the burner can operate at high productivity levels from the start without risk of thermal degradation, extending service life and reliability.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If the number of oxy-burners is increased to improve temperature uniformity, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature uniformityVSAvoidburner system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Each oxy-burner is designed as a universal module with integrated cooling channels that can be installed in standardized positions along the forehearth. The modular design with multi-functional components (heating flame plus integrated cooling protection) reduces the variety of different burner types needed, simplifying the overall system despite having multiple burners for temperature uniformity control.

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

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 cooling unit significantly reduces the frequency of oxy-burner cleaning operations, extends their service life, and allows for a broader range of flow rates, ensuring the oxy-burner operates within safe temperature limits, thereby enhancing operational efficiency and longevity.

Implementation Method 1

a cooling channel (3C) defined by walls and comprising an inlet (3U) and an outlet (3D) for circulating a refrigerating fluid

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

The downstream end (1D) of the burner is in thermal contact with the aperture wall of the cooling plate

Methodology Applied
Scientific EffectThermal Conduction: Conduction (thermal)

Implementation Method 3

the oxygen and fuel flowing through an oxy-burner and mixed at a tip of the oxy-burner act as cooling medium

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Data Source

PatentEP3420276B1Glass fibre manufacturing plant comprising oxy-burner having cooling unit
Publication Date: 2021.04.14 3B FIBERGLASS SPRL
  • EP3420276B1 patent drawingFigure 1(a)~1(b)
  • EP3420276B1 patent drawingFigure 2(a)~2(b)
  • EP3420276B1 patent drawingFigure 3(a)~3(b)

AI summary

The present invention concerns a glass fibre manufacturing plant comprising a forehearth (31) comprising a longitudinal wall provided with at least one burner assembly comprising: (A) a burner block (20) made of a refractory material and comprising a through-passage and comprising a hot surface (20H) forming a portion of the longitudinal wall (31 L); and (B) a burner sub-assembly comprising: (a) an oxy-burner (1) comprising a downstream end ending at a free end of the downstream end, wherein a cross-sectional area of said downstream end of the oxy-burner body decreases towards the free end of the downstream end; characterized in that, the burner sub-assembly further comprises: (b) a cooling unit (3) comprising: · a cooling plate (5) comprising an aperture which geometry matches the geometry of the downstream end of the oxy-burner which is inserted in said aperture to form a thermal contact therewith; • a cooling channel (3C) defined by walls and comprising an inlet (3U) and an outlet (3D) for circulating a refrigerating fluid, wherein a cooling wall (5W) of said cooling channel is formed by a portion of the cooling plate, and in that, the cooling plate is encased in the through-passage.