Glass Ribbon Cooling Shielding for Uniform Heat Transfer
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Solution Overview
Problem
In glass manufacturing, variations in ribbon thickness lead to uneven cooling, causing thicker regions to set out of plane and potentially resulting in sheet breakage due to non-uniform heat transfer via radiation.
Innovation Solution
An apparatus and method that include a transition region with a heating mechanism, a cooling mechanism, and a shielding mechanism to manage heat transfer, where the cooling mechanism extends between the heating mechanism and the glass ribbon, and the shielding mechanism blocks radiation heat transfer between the cooling mechanism and the bead regions, allowing for more uniform cooling while accounting for thickness differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If radiation cooling is used as the dominant heat transfer mechanism, then cooling efficiency is improved, but thickness variations cause non-uniform cooling leading to sheet breakage
Solution Approach 1:
The patent applies different thermal conditions to different regions of the glass ribbon. Heating mechanisms are positioned to provide localized heating to the central region, while cooling mechanisms are positioned to provide localized cooling to the bead regions. This creates non-uniform thermal treatment that compensates for the non-uniform thickness distribution, ensuring uniform cooling rates across the ribbon width and preventing sheet breakage.
Solution Approach 2:
The patent applies preliminary heating to thicker bead regions before the dominant radiation cooling phase. This preliminary anti-action counteracts the excessive cooling that would otherwise occur in thicker regions, balancing the thermal history across different thickness zones and preventing the thermal stresses that lead to sheet breakage.
2Ease of manufacture
If uniform cooling is applied across the glass ribbon, then manufacturing simplicity is maintained, but thickness variations cause out-of-plane setting and quality defects
Solution Approach 1:
The patent implements localized heating and cooling zones with different thermal characteristics. Heating elements are positioned to target the central region, while cooling elements are positioned to target the bead regions. This localized differential thermal treatment compensates for thickness variations and maintains ribbon flatness without requiring complex overall process changes.
Solution Approach 2:
The patent changes thermal parameters (temperature, heating/cooling intensity) across different spatial locations of the glass ribbon. By varying these parameters locally rather than applying uniform conditions, the system achieves precise control over cooling rates to maintain ribbon flatness while accounting for thickness variations.
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 approach ensures more uniform heat transfer across the glass ribbon, reducing the risk of sheet breakage by maintaining the ribbon's plane and minimizing stress gradients during cooling.
Implementation Method 1
the amount of radiation heat transfer from the glass ribbon is, in part, a function of the emissivity of the ribbon
Implementation Method 2
the newly formed ribbon of glass is cooled with radiation being the dominant form of heat transfer
Data Source
AI summary
A method and apparatus for manufacturing a glass article includes flowing a glass ribbon through a transition region, heating the glass ribbon with a heating mechanism housed in the transition region, cooling the glass ribbon with a cooling mechanism housed in the transition region, wherein the cooling mechanism extends between the heating mechanism and the glass ribbon, and shielding the glass ribbon with a shielding mechanism that extends between the cooling mechanism and at least one of first and second bead regions of the glass ribbon.