Glass Ribbon Edge Cooling for Width Contraction Control
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Solution Overview
Problem
The existing methods for forming glass ribbons result in significant width contraction due to cooling and surface tension, leading to reduced usable width and thickness, as the edges of the glass ribbon become thicker and stiffer, making them unsuitable for sale.
Innovation Solution
A method involving a treatment roller and edge rollers to control the viscosity of the molten glass, where the edge rollers cool the edge portions of the glass layer without contacting the central portion, thereby reducing contraction and maintaining a stable central surface, allowing for a glass ribbon with increased usable width and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the molten glass layer is cooled on the treatment roller and below, then the glass ribbon is formed and solidified, but the glass ribbon contracts in width direction and the edges thicken, reducing the useable width
Solution Approach 1:
The patent applies different cooling rates to different regions of the glass ribbon. The central portion is cooled at a first cooling rate while the edge portions are cooled at a second cooling rate that is slower than the first cooling rate. This differential cooling prevents excessive contraction at the edges, maintaining a more uniform width across the glass ribbon and increasing the useable width.
2Stability of the object's composition
If the edges of the glass ribbon are cooled rapidly, then the central surface remains stable, but the edges become thicker and stiffer, making them unsuitable for sale
Solution Approach 1:
The patent implements selective cooling where the central portion of the glass ribbon is cooled at a faster rate than the edge portions. This creates a temperature gradient that stabilizes the central surface while preventing excessive cooling and thickening of the edges, thereby maintaining suitable edge properties for sale.
Solution Approach 2:
The patent applies a preliminary anti-action by using slower cooling rates at the edge portions to counteract the natural tendency of rapid cooling that would cause edge thickening and stiffening. This preventive measure ensures the edges remain suitable for sale while the central surface achieves the necessary stability.
3Stability of the object's composition
If the molten glass is flowed over the treatment roller for the entire circumference, then the glass layer is uniformly cooled, but the edges contract excessively and the useable width is reduced
Solution Approach 1:
The patent divides the treatment roller into different functional zones: a first region for the central portion that provides uniform cooling at a first cooling rate, and a second region for the edge portions that provides slower cooling at a second cooling rate. This zonal differentiation maintains uniformity in the central area while preventing excessive contraction at the edges, thereby increasing the useable width.
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 effectively minimizes widthwise contraction of the glass ribbon, maintaining a stable central surface and increasing the usable width and thickness, thus enhancing the quality and utility of the glass sheets produced.
Implementation Method 1
flowing a stream of molten glass on an outer surface of a treatment roller... the stream of molten glass forming a molten glass layer on the outer surface of the treatment roller
Implementation Method 2
contacting an edge portion of the molten glass layer on the treatment roller with a first edge roller... the contacting cooling the edge portion and increasing a viscosity thereof
Data Source
AI summary
A method and an apparatus for forming and treating a glass ribbon. The apparatus includes a treatment roller and an edge roller that contacts an edge portion of a layer of glass disposed on the treatment roller. The edge roller cools the edge portion of the glass layer, the cooled edge portion attaining an increased viscosity compared to a center portion of the glass layer. Embodiments may include a second edge roller that contacts and cools an opposing edge portion of the glass layer. The cooled edge portions can resist widthwise contraction of the glass layer and the glass ribbon formed therefrom.