Muffle Assembly Cooling Tubes for Glass Ribbon Thickness Control
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Solution Overview
Problem
Existing glass forming apparatuses face challenges in controlling the temperature of molten glass during fusion processes, particularly in achieving desired temperature gradients for laminated glass ribbons, which affects the thickness ratios of glass plies and manufacturing precision.
Innovation Solution
A muffle assembly with at least one first cooling tube and one second cooling tube, positioned parallel to each other, is integrated into the glass forming apparatus, with refractory materials in direct contact to form continuous heat conduction pathways, creating a vertical temperature gradient between the forming bodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional glass forming apparatuses are used without additional cooling tubes, then the device complexity is low, but the temperature control precision and manufacturing precision of glass ribbon thickness ratios deteriorate
Solution Approach 1:
The muffle assembly is segmented into multiple functional components: first cooling tubes, second cooling tubes, first refractory materials, and second refractory materials. Each component serves a specific thermal control function, allowing independent adjustment of temperature gradients to achieve precise control over glass ribbon thickness ratios.
Solution Approach 2:
Different regions of the muffle assembly are assigned different thermal properties through the strategic placement of cooling tubes and refractory materials. The first cooling tubes and first refractory materials create specific temperature zones, while the second cooling tubes and second refractory materials create complementary zones, enabling localized temperature control to achieve the desired vertical temperature gradient.
2Manufacturing precision
If multiple cooling tubes with refractory materials are added to create temperature gradients, then the temperature control precision improves, but the device complexity increases
Solution Approach 1:
The muffle assembly with multiple cooling tubes and refractory materials serves multiple functions simultaneously: it creates the primary temperature gradient for glass flow control, provides thermal insulation where needed, and enables independent temperature zone adjustment. This multi-functionality allows a single assembly to address multiple process requirements without proportionally increasing complexity.
3Temperature
If cooling tubes are positioned parallel to forming surfaces with direct contact refractory materials, then the temperature gradient establishment improves, but the heat conduction pathway complexity increases
Solution Approach 1:
Refractory materials serve as thermal intermediaries between the cooling tubes and the forming bodies. The first refractory materials mediate heat transfer from the first cooling tubes to the first forming bodies, while the second refractory materials mediate heat transfer from the second cooling tubes to the second forming bodies. This intermediary approach enables controlled heat conduction pathways that establish the desired temperature gradient without requiring direct metal-to-glass contact.
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 configuration effectively establishes a significant temperature gradient, enabling precise control over the glass ribbon's thickness ratios and improving manufacturing consistency by efficiently extracting heat from the molten glass, achieving gradients of over 100°C.
Implementation Method 1
A first refractory material may be disposed between the at least one first cooling tube and the first outer forming surface of the forming body. The first refractory material may be in direct contact with the at least one first cooling tube thereby forming a first continuous heat conduction pathway between the first refractory material and the at least one first cooling tube
Implementation Method 2
Heat may be extracted from the molten core glass composition flowing over the first outer forming surface and the second outer forming surface of the lower forming body with at least one first cooling tube extending substantially parallel to the first outer forming surface
Implementation Method 3
The first refractory material may be in direct contact with the at least one first cooling tube thereby forming a first continuous heat conduction pathway between the first refractory material and the at least one first cooling tube in a substantially horizontal direction
Data Source
AI summary
Described herein are glass forming apparatuses with cooled muffle assemblies and methods for using the same to form glass ribbons. According to one embodiment, a muffle assembly for a fusion forming apparatus may include a muffle frame comprising a back wall, a front wall opposite the back wall, and a pair of sidewalls joining the front wall to the back wall in a closed-loop. At least one first cooling tube may extend through the back wall and the front wall across the closed-loop. At least one second cooling tube may extend through the back wall and the front wall across the closed loop such that the at least one second cooling tube is spaced apart from and parallel with the at least one first cooling tube.