Method for controlling transverse temperature difference of molten glass in tin bath in production of ultrathin float glass

Abstract

The invention discloses a method for controlling the transverse temperature difference of molten glass in a tin bath in ultrathin float glass production, and relates to the technical field of glass production. According to the invention, the tin bath is precisely divided into 59 electric heating areas, so that the electric heating parameters of each motor hot area can be respectively adjusted, the transverse temperature difference of molten glass in the tin bath in the glass production process is obviously reduced, and the production loss of broken plates caused by uneven glass stress due to the transverse temperature difference is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of glass production, and in particular to a method for controlling the lateral temperature difference of tin bath glass liquid in the production of ultra-thin float glass. Background Art

[0002] In the production process of ultra-thin float glass, the significance of annealing is the cooling process with a certain temperature curve. Its purpose is to eliminate the residual internal stress and optical unevenness in the glass. Due to the ultra-thin thickness of ultra-thin glass, the heat dissipation is extremely rapid, and the resulting longitudinal and transverse temperature difference is large, which makes the stress greater than that of conventional glass. Because the ultra-thin thickness makes the glass strength smaller, as the stress increases, the glass will be distorted and deformed, forming permanent warping, and when the limit value is exceeded, the plate will explode and break. Therefore, how to effectively control the rate of reduction of the transverse and longitudinal temperature of the glass plate is the core of the annealing process.

[0003] The inlet temperature of the glass ribbon in the annealing furnace is determined according to the outlet temperature of the tin bath. The outlet temperature of the tin bath shall not be lower than 575℃. If it is too low, the process effect of the A zone of the annealing furnace will be affected due to insufficient heat of the glass ribbon, resulting in insufficient lateral heat uniformity and even failure to meet the control index. The heat can only be supplemented by starting a large amount of electric heating.

[0004] The control standard requirements of Zone A of the annealing furnace are, first, high uniformity of heat, and second, accuracy. In the existing ultra-thin float glass production process, there is always a lateral temperature difference in the tin bath. Generally, the temperature in the middle is high and the temperature on both sides is low, which leads to a large flow rate in the middle of the glass liquid and a small flow rate on both sides. The finished glass is thick in the middle and thin on both sides. Although there is electric heating for adjustment, there is no partition between the electric heating, and the heat dissipates rapidly in the space, so that the longitudinal temperature of the glass edge at the outlet of the tin bath, i.e. the entrance of Zone A of the annealing furnace, still does not meet the standard, and the lateral temperature difference of the glass is large, which causes uneven stress of the glass due to the temperature difference problem, resulting in production losses of broken glass.

[0005] Therefore, in order to solve the above problems, it is necessary to provide a method for controlling the lateral temperature difference of the glass liquid in the tin bath. Summary of the invention

[0006] The technical problem to be solved by the present invention is: to overcome the shortcomings of the prior art and provide a method for controlling the lateral temperature difference of the glass liquid in the tin bath in the production of ultra-thin float glass, by accurately dividing the tin bath into a total of 59 electric heating zones, so that the electric heating parameters of each motor heating zone can be adjusted separately, thereby significantly reducing the lateral temperature difference of the glass liquid in the tin bath during the glass production process, thereby avoiding the production loss of broken plates caused by uneven glass stress due to the lateral temperature difference.

[0007] The technical solution of the present invention is: A method for controlling the lateral temperature difference of glass liquid in a tin bath in the production of ultra-thin float glass, wherein the tin bath includes 22 Å in the longitudinal direction, wherein: The 1-2 Bei area is divided into 1#-5# electric heating areas horizontally; The 3-4 Bei area is divided into 6#-10# electric heating areas; The 5-6 Bei area is divided into 11#-19# electric heating areas; The 7-8 Bei area is divided into 20#-28# electric heating areas; The 9-10 Bei area is divided into 29#-35# electric heating areas; The 11-12 Bei area is divided into 36#-40# electric heating areas; The 13-14 Bei area is divided into 41#-45# electric heating areas; The 15-16 Bei area is divided into 46#-50# electric heating areas; The 17-18 Bei area is divided into 51#-54# electric heating areas; The 19-21 Bei area is divided into 55#-59# electric heating areas; By adjusting the temperature of each electric heating zone, the lateral temperature difference of the glass liquid in the tin bath can be controlled.

[0008] Preferably, thermocouples are provided on both sides of the tin bath corresponding to the 1-2 Bei, 5-6 Bei, 7-8 Bei, 11-12 Bei, 15-16 Bei, 17-18 Bei, and 19-21 Bei regions.

[0009] Preferably, the temperature of the 1-4 Bei region in the tin bath is 980-1060°C, the temperature of the 5-10 Bei region is 890-980°C, the temperature of the 11-16 Bei region is 730-890°C, and the temperature of the 17-21 Bei region is 600-730°C.

[0010] Preferably, partitions are used to divide the tin bath into a total of 59 electric heating zones.

[0011] Preferably, the partition is made of the same material as the top cover bricks.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The method of controlling the lateral temperature difference of the glass liquid in the tin bath of the present invention can accurately divide the tin bath into a total of 59 electric heating zones, so that the electric heating parameters of each motor heat zone can be adjusted separately, which can not only accurately control the rate of longitudinal and lateral temperature reduction of the glass liquid in the bath, so that the lateral temperature difference of the glass plate in the tin bath can be effectively reduced, thereby improving production efficiency and product quality, but also reducing power consumption and saving resources. The present invention aims to significantly reduce the lateral temperature difference of the glass liquid in the tin bath during the glass production process, so that the glass plate can achieve the uniformity and accuracy required by the zone A of the annealing furnace when entering the zone, thereby avoiding the production loss of broken plates caused by uneven glass stress due to the lateral temperature difference. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the tin bath in the present invention.

[0014] Figure 2 It is a distribution diagram of the electric heating zone in the tin bath of the present invention.

[0015] In the figure, 1. tin bath; 2. partition; 3. electric heating rod; 4. glass liquid; 5. tin liquid; 6. top cover brick; 7. electric heating zone. DETAILED DESCRIPTION

[0016] In order to enable persons skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0017] like Figure 1 As shown, the tin bath 1 is filled with tin liquid 5, and glass liquid 4 floats on the tin liquid 5. An electric heating rod 3 is arranged on the top of the tin bath 1 to heat the glass liquid 4. A partition 2 made of the same material as the top cover brick 6 is also arranged to divide the tin bath 1 into a total of 59 electric heating zones 7.

[0018] In order to control the lateral temperature difference of the glass liquid 4 in the tin bath 1, the present invention provides a method for controlling the lateral temperature difference of the glass liquid in the tin bath during the production of ultra-thin float glass, such as Figure 2 As shown, the tin bath 1 includes 22 longitudinal sections, wherein: The 1-2 Bei area is laterally divided into 1#-5# electric heating zones 7; The 3-4 Bei area is divided into 6#-10# electric heating areas 7; The 5-6 Bei area is divided into 11#-19# electric heating zones 7; The 7-8 Bei area is divided into 20#-28# electric heating area 7; The 9-10 Bei area is divided into 29#-35# electric heating zones 7; The 11-12 Bei area is divided into 36#-40# electric heating area 7; The 13-14 Bei area is divided into 41#-45# electric heating areas 7; The 15-16 Bei area is divided into 46#-50# electric heating area 7; The 17-18 Bei area is divided into 51#-54# electric heating area 7; The 19-21 Bei area is divided into 55#-59# electric heating area 7; By adjusting the temperature of each electric heating zone 7, the lateral temperature difference of the tin bath 1 and the glass liquid 4 can be controlled.

[0019] Among them, thermocouples are respectively arranged on both sides of the tin bath 1 corresponding to the 1-2 Bei, 5-6 Bei, 7-8 Bei, 11-12 Bei, 15-16 Bei, 17-18 Bei, and 19-21 Bei regions; and the temperature of the 1-4 Bei region in the tin bath 1 is 980-1060℃, the temperature of the 5-10 Bei region is 890-980℃, the temperature of the 11-16 Bei region is 730-890℃, and the temperature of the 17-21 Bei region is 600-730℃.

[0020] Example 1 When a certain ultra-thin float glass production line produces 1mm thick glass, the power and thermocouple temperature measurement of 59 electric heating zones 7 in the tin bath 1 are shown in Table 1: Table 1 Power and thermocouple temperature measurement of 59 electric heating zones

[0021] A total of 7 pairs of thermocouples are set in the tin bath to control the lateral temperature difference at 0-2℃.

[0022] It can be seen from Table 1 that the two thermocouples in the 5-6 Bei area measured temperatures of 973°C and 968°C respectively, which means that the lateral temperature difference in this area is 5°C. The temperature difference is too large, so the electric heating opening of the 17# electric heating zone on the side with lower temperature can be increased by 1%, the electric heating opening of the 18# electric heating zone can be increased by 2%, and the electric heating opening of the 19# electric heating zone can be increased by 3%, so that the temperature measured by the thermocouple on one side increases from 968°C to 972°C, thereby controlling the lateral temperature difference in this area to 1°C.

[0023] The two thermocouples in the 11-12 Bei area measured temperatures of 887°C and 890°C respectively, which means that the lateral temperature difference in this area is 3°C. The temperature difference is too large, so the electric heating opening of the 36# electric heating zone on the side with lower temperature can be increased by 2%, and the electric heating opening of the 37# electric heating zone can be increased by 1%, so that the temperature measured by the thermocouple on one side rises from 887°C to 890°C, thereby controlling the lateral temperature difference in this area to 0°C.

[0024] Before using the control method of the present invention, the frequency of plate breakage in the tin bath was once a week on average, and the product yield was 90%. After using the control method of the present invention, the electric heating power was accurately controlled by partitioning and zoning, thereby effectively reducing the lateral temperature difference of the glass plate in the tin bath. Except for large-scale defects, plate breakage did not occur, and the glass plate yield was increased from 90% to 98%.

Claims

1. A method for controlling the lateral temperature difference of molten glass in a tin bath during production of ultra-thin float glass, characterized in that: The tin bath (1) includes 22 shells in the longitudinal direction, wherein: The 1-2 Bei area is laterally divided into 1#-5# electric heating zones (7); The 3-4 Bei area is divided into 6#-10# electric heating areas (7); The 5-6 Bei area is divided into 11#-19# electric heating areas (7); The 7-8 Bei area is divided into 20#-28# electric heating areas (7); The 9-10 Bei area is divided into 29#-35# electric heating areas (7); The 11-12 Bei area is divided into 36#-40# electric heating areas (7); The 13-14 Bei area is divided into 41#-45# electric heating areas (7); The 15-16 Bei area is divided into 46#-50# electric heating areas (7); The 17-18 Bei area is divided into 51#-54# electric heating areas (7); The 19-21 Bei area is divided into 55#-59# electric heating areas (7); By regulating the temperature of each electric heating zone (7), the lateral temperature difference between the tin bath (1) and the glass liquid (4) can be controlled.

2. The method for controlling the lateral temperature difference of molten glass in the tin bath in the production of ultra-thin float glass according to claim 1, characterized in that: Thermocouples are respectively arranged on both sides of the tin bath (1) corresponding to the 1-2 Å, 5-6 Å, 7-8 Å, 11-12 Å, 15-16 Å, 17-18 Å, and 19-21 Å regions.

3. The method for controlling the lateral temperature difference of molten glass in the tin bath in the production of ultra-thin float glass according to claim 1, characterized in that: The temperature of the 1-4 Å region in the tin bath (1) is 980-1060°C, the temperature of the 5-10 Å region is 890-980°C, the temperature of the 11-16 Å region is 730-890°C, and the temperature of the 17-21 Å region is 600-730°C.

4. The method for controlling the lateral temperature difference of molten glass in the tin bath in the production of ultra-thin float glass according to claim 1, characterized in that: The tin bath (1) is divided into a total of 59 electric heating zones (7) by partitions (2).

5. The method for controlling the lateral temperature difference of molten glass in the tin bath in the production of ultra-thin float glass according to claim 4, characterized in that: The partition plate (2) is made of the same material as the top cover brick (6).

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