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What's The Importance of Annealing in Float Glass Production Line?

Views: 11     Author: Site Editor     Publish Time: 2023-12-20      Origin: Site

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This article will introduce the role of annealing in the float glass production line, the consequences of improper annealing, and provide precautions for using the annealing furnace.


The definition and function of float glass annealing

In the float glass production line, the annealing furnace is one of the three major thermal equipment. The annealing of glass is an important link in the glass production process. The continuous glass ribbon with a temperature of about 600°C drawn from the tin bath enters the annealing kiln through the transfer roller table. Annealing and cooling are performed in the kiln. Through appropriate temperature drop, the residual internal stress generated in the glass ribbon can be controlled within the allowable range, and the glass ribbon leaves the annealing kiln and enters the cold end unit at a temperature lower than 70°C.


The annealing of float glass can be divided into two main processes: one is to weaken or eliminate the internal stress of the glass, and the other is to prevent the regeneration of internal stress. The weakening and elimination of internal stress in glass history is based on the relaxation theory; the so-called internal stress relaxation refers to the process of dissipating the internal stress of the material under the action of molecular thermal motion. The relaxation speed of the internal stress is largely determined by the glass The temperature at which it is located.


The main function of annealing is to eliminate residual internal stress and optical inhomogeneity in float glass, and to stabilize the internal structure of the glass. It has a very important impact on the product quality, yield and energy consumption of float glass.


What are the consequences of improper annealing of float glass?

Improper annealing of float glass can lead to various negative consequences that affect the quality and performance of the glass product. Some of the main consequences of insufficient annealing include:


1. Inadequate or incorrect annealing can result in residual internal stresses within the glass.


These residual stresses can cause unexpected rupture of float glass, posing a safety hazard. This is particularly important for applications where glass is used as a structural or safety component.


2. Inadequate annealing can cause optical distortion, such as waviness or warping of the glass.

This compromises the visual quality of the glass, making it unsuitable for applications where optical clarity is critical, such as architectural windows or car windshields.


3. Improper annealing may result in the formation of glass surface defects, including scratches, bubbles, or other imperfections.

These defects not only affect the aesthetics of the glass but also weaken its structural integrity.


4. Insufficient annealing can cause the glass to become mechanically less strong, making it more susceptible to cracking under mechanical or thermal stress.

This is an important issue, especially in applications where the glass is subjected to external forces or temperature changes.


5.Proper annealing is critical to maintaining uniform thickness throughout the glass sheet.

Insufficient annealing can result in thickness variations that may affect the suitability of the glass for certain applications, such as in structures where precise dimensions are necessary.


In contrast to the above consequences, proper annealing of float glass has many benefits, including minimizing internal stresses, enhancing mechanical strength, and improving thermal stability. The controlled cooling process during annealing ensures a uniform glass structure, helping to improve flatness, smoothness and reduce optical distortion.


Precautions for using annealing furnace in float glass production line

1. The annealing kiln roller table should be inspected frequently, and any abnormalities such as stalling and pauses should be dealt with promptly.


2. During normal production, the annealing curves of different types of glass should be formulated by the technical department, and other personnel are not allowed to change them without authorization.


3. Regularly check the broken glass situation in the annealing kiln, especially after dealing with tin bath accidents. Too much broken glass in the annealing furnace will affect the temperature control or block the operation of the glass ribbon and scratch the glass.


4. Before starting the fans in each area of the annealing kiln, the inlet or outlet valves should be closed first, and after normal operation, slowly open the manual valves.


5. Annealing workers must inspect all fans and main drive motors of the annealing kiln every 2 hours, and deal with problems in a timely manner; broken glass in the kiln must also be cleaned up in time to avoid affecting temperature control.


6. When production is abnormal or production adjustments are made, if there is a large deviation between the measured temperature and the set temperature, manual control should be used instead.


7. When a power outage occurs, you should first check whether the main drive and the backup 5.5kW motor are operating normally to ensure that the rollers do not stop rotating to avoid deformation of the rollers and affecting production.


8. Try to prevent cold wind from entering the annealing kiln. When breaking the glass, open the operating door as little as possible, and do not open it on both sides to avoid the draft from causing the glass plate to burst.


About US - Choice of glass production factory

Nanjing Baisheng Glass Technology Co., Ltd is a global glass technology equipment engineering system integration service provider located in the Airport Science & Technology Industrial Park, Lishui District, Nanjing. The company offers comprehensive services encompassing glass engineering R & D, engineering construction, equipment manufacturing, commissioning, and production and operation. Boasting over 20 sets of advanced intelligent manufacturing and system equipment, the company has a strong foundation in glass technology.


Nanjing Baisheng has accumulated nearly 20 years of experience in constructing glass factories, cold and hot repairs of melting furnaces, furnace heat-up, and equipment manufacturing for glass production lines. The company holds patented technology and expertise in various glass types, including photovoltaic calendered glass, small and medium float energy-saving glass, water glass, light industrial energy-saving glass, and all oxygen and electric boosting glass furnaces.


With a robust talent structure comprising more than 60 professional engineering and technical personnel, including over 20 with medium and senior technical titles, Nanjing Baisheng focuses on continuous innovation. If you have any questions about glass production, especially float glass production lines, please contact us and our technical staff will provide you with professional answers.



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