Glass Sheet Annealing Heat-Insulating Plate Design
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Solution Overview
Problem
In glass sheet manufacturing by the downdraw method, achieving precise heat management to minimize distortion and thickness deviation is challenging due to heat exchange issues through gaps between annealing spaces, which complicates controlling the desired temperature profile.
Innovation Solution
The method involves using heat-insulating plates with adjustable gaps and shaped surfaces to match the glass sheet's thickness variation, reducing heat movement between annealing spaces and allowing precise temperature control from top to bottom, thereby minimizing distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gap between heat-insulating plates is increased to accommodate thicker end portions of the glass sheet, then the glass sheet can be held without touching the plates, but heat exchange between annealing spaces increases making temperature control difficult
Solution Approach 1:
The heat-insulating plates are designed with different gap distances at different locations: a first gap distance at the center portion and a second gap distance (larger than the first) at the end portions. This local variation in gap size allows the plates to accommodate the thickness variation of the glass sheet while minimizing heat exchange between annealing spaces, thus resolving the contradiction between holding the glass sheet and maintaining temperature control.
2Manufacturing precision
If heat-insulating plates are used to partition annealing spaces, then temperature profile control is improved, but heat exchange through gaps increases when gaps are large
Solution Approach 1:
The heat-insulating plates implement local quality by having different gap distances at different positions along the glass sheet width. The smaller gap at the center and larger gap at the ends are optimized to balance temperature control precision with heat exchange minimization, allowing the system to maintain precise temperature profiles while reducing energy loss through gaps.
3Device complexity
If a single sheet heat-insulating plate is used, then the structure is simple, but the gap must be large enough to accommodate thickness variation causing poor heat management
Solution Approach 1:
The heat-insulating plate structure is segmented into multiple regions with different gap characteristics. By dividing the plate into zones with different gap distances (first gap at center, second gap at ends), the system achieves precise heat management while maintaining structural simplicity. This segmentation allows each region to be optimized for its specific function.
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 enhances the precision of heat management, reducing distortion and thickness deviation in glass sheets, meeting stricter quality requirements for glass substrates used in liquid crystal display devices.
Implementation Method 1
The heat-insulating plates suppress the movement of heat between the annealing spaces, and are provided to control the atmospheric temperature of each annealing space so that a desired temperature profile is obtained
Implementation Method 2
a facing surface of the heat-insulating plate is shaped so as to correspond to a sheet thickness variation of the glass sheet, so that a gap between the glass sheet and the heat-insulating plate is substantially uniform
Data Source
AI summary
A method of manufacturing a glass sheet includes creating split flows of molten glass in a forming body (10) and causing the molten glass to flow down, subsequently merging the flows at a merging point to form a glass sheet G and causing the glass sheet to flow downward in the vertical direction. A plurality of chambers (42b, 42c, . . . ) separated by heat-insulating plates (40a, 40b, . . . ) in the direction of movement of the glass sheet G are provided. A heater (60a, 60b, . . . ) is provided for each of the chambers (42b, 42c, . . . ) so that the temperature decreases in the direction of movement. The heat-insulating plates (40a, 40b, . . . ) are disposed facing the glass sheet G, and facing surfaces of the heat-insulating plates (40a, 40b, . . . ) are shaped so as to correspond to a sheet thickness variation of the glass sheet G.