Method for controlling foreign matter in glass sheets in an ultra-thin float glass tin bath

Abstract

The application discloses a kind of control methods of glass plate foreign matter in ultra-thin float glass tin bath, foreign matter is group, maximum diameter ≥20mm and maximum diameter / glass plate outlet ramp maximum line inclination <6.1, raise tin bath outlet temperature and retaining wall and retaining curtain height;Foreign matter maximum diameter ≥20mm and maximum diameter / glass plate outlet ramp maximum line inclination ≥6.1, raise tin bath outlet temperature and retaining wall and retaining curtain height, increase glass plate thickness;Foreign matter is strip, maximum thickness ≥18mm and maximum thickness / glass plate outlet ramp maximum line inclination <5.3, raise tin bath outlet temperature and retaining wall and retaining curtain height;Foreign matter maximum thickness ≥18mm and maximum thickness / glass plate outlet ramp maximum line inclination ≥5.3, raise tin bath outlet temperature and retaining wall and retaining curtain height, increase glass plate thickness.The application takes different control measures according to different foreign matter conditions, reduces the production loss caused by glass plate foreign matter.

Description

Technical Field

[0001] This invention relates to the field of glass production technology, specifically to a method for controlling foreign matter in a tin bath of ultra-thin float glass. Background Technology

[0002] During the tin bath forming stage of float ultrathin electronic glass, it is necessary to monitor the glass production status and equipment operation in the tin bath in real time to avoid problems in glass production and equipment failures that could adversely affect the product. In this process, foreign objects in the glass plate are a key aspect that needs to be controlled in the production of tin bath glass.

[0003] Foreign objects in glass plates are mainly formed by poor melting of glass raw materials. Unmelted clumps or abnormally composed molten glass are trapped in the glass plate, generally appearing as white clumps or bands. Other foreign objects include lumps of refractory material that have burned onto the glass, and slag drips. When the glass plates in the tin bath reach the tin bath outlet, they need to be transported up a roller conveyor with a certain curvature (e.g., Figure 1 As shown, glass requires a certain degree of flexibility when climbing an incline. When foreign objects are present on the glass plate, the local stress-bearing capacity of the glass decreases, leading to a plate breakage accident at the tin bath outlet. In this case, the glass plate cannot be pulled out of the tin bath by the roller conveyor, resulting in significant production losses. After a plate breakage occurs, emergency handling is required on-site in the tin bath: first, the plate is pulled back, and then the glass plate operation is resumed before adjusting the parameters to produce qualified glass. Since no good glass can be produced during the plate breakage, it causes enormous losses. Therefore, a control method is needed to promptly detect foreign objects on the glass plate and prevent or quickly carry out emergency handling to reduce losses. Summary of the Invention

[0004] 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 foreign objects in the tin bath of ultra-thin float glass. For the tin bath section in the float glass forming process, different control measures are taken according to different foreign object situations, which can detect foreign objects in time and prevent or quickly carry out emergency treatment, ultimately reducing the production losses caused by foreign objects in the glass plate.

[0005] The technical solution of this invention is as follows:

[0006] Methods for controlling foreign objects in the tin bath of ultra-thin float glass:

[0007] The foreign object in S1 is in clumps.

[0008] When the maximum diameter of the foreign object in S11 is less than 20mm, no control is required.

[0009] When the maximum diameter of the foreign object in S12 is ≥20mm and the maximum diameter / maximum slope angle of the glass plate outlet is <6.1, the outlet temperature of the tin bath is increased to reduce the viscosity of the glass, thereby increasing its flexibility and reducing its brittleness, thus improving the glass's flexural strength to resist the decrease in local flexural strength caused by the foreign object; at the same time, the height of the baffle wall and the baffle curtain are increased; after the foreign object passes through the outlet of the tin bath, the outlet temperature of the tin bath and the height of the baffle wall and the baffle curtain are restored to their original values.

[0010] When the maximum diameter of the foreign object in S13 is ≥20mm and the maximum inclination angle of the maximum diameter / glass plate outlet ramp is ≥6.1, the outlet temperature of the tin bath is increased, the thickness of the glass plate is increased, and the height of the baffle wall and curtain is increased. After the foreign object passes through the outlet of the tin bath, the outlet temperature of the tin bath, the thickness of the glass plate, and the height of the baffle wall and curtain are restored to their original values. Among them, the edge-pulling wheel at the front end of the edge-pulling machine pulls the glass plate with a certain viscosity floating on the surface of the tin bath forward. Therefore, the thickness of the glass plate and the width of the glass plate can be controlled and stabilized by adjusting the linear speed, horizontal swing angle and plane inclination angle of the edge-pulling wheel.

[0011] The foreign object in S2 is ribbon-like.

[0012] When the maximum thickness of the foreign object in S21 is less than 18mm, no control is required.

[0013] When the maximum thickness of the foreign object is ≥18mm and the maximum thickness / maximum slope angle of the glass plate outlet is <5.3, increase the outlet temperature of the tin bath and increase the height of the baffle wall and curtain; after the foreign object passes through the outlet of the tin bath, restore the outlet temperature of the tin bath to the original temperature value and adjust the height of the baffle wall and curtain to the original height value.

[0014] When the maximum thickness of the foreign object is ≥18mm and the maximum thickness / maximum slope angle of the glass plate outlet is ≥5.3, increase the tin bath outlet temperature, increase the glass plate thickness, and increase the height of the baffle wall and curtain; after the foreign object passes through the tin bath outlet, restore the tin bath outlet temperature, glass plate thickness, and the height of the baffle wall and curtain to their original values.

[0015] Preferably, in step S12, the temperature rise at the tin bath outlet is ΔT1, where ΔT1 = 0.0023 × maximum diameter. 2 × Maximum diameter / Maximum inclination angle of the tin bath outlet ramp, where ΔT1 is in °C and 0.0023 is in °℃ / mm. 3 The unit for the maximum diameter is mm, and the unit for the maximum inclination angle of the tin bath outlet ramp is °.

[0016] Preferably, to minimize the impact of the heating in step S12 on production, an optimal heating point needs to be determined. Heating begins at the solder bath outlet when the foreign object moves to this optimal point. Figure 3As shown, the distance L1 from the tin bath outlet to the optimal heating point is calculated as follows: L1 = ΔT1 ÷ heating rate × glass plate moving speed, where L1 is in meters, ΔT1 is in degrees Celsius, the heating rate is in degrees Celsius / min, and the glass plate moving speed is in meters / min.

[0017] Preferably, in steps S12 and S13, the height increase of the retaining wall and the curtain is ΔH1, where ΔH1 = maximum diameter + 5 - original height of the retaining wall and curtain, and the units of ΔH1, maximum diameter, 5, and original height of the retaining wall and curtain are mm.

[0018] Preferably, in step S13, the temperature rise at the tin bath outlet is ΔT2, where ΔT2 = 0.0023 × maximum diameter. 2 × Maximum diameter / Maximum inclination angle of the tin bath outlet ramp line, where ΔT2 is in °C and 0.0023 is in °℃ / mm. 3 The unit for the maximum diameter is mm; the unit for the maximum inclination angle of the tin bath outlet ramp is °; maximum diameter / maximum inclination angle of the tin bath outlet ramp = 6.1 mm / °; glass plate thickness increase ΔD1 = 3.1 × 10⁻⁶ -7 ×Maximum Diameter 4 Where ΔD1 is in mm, 3.1 × 10⁻⁶ -7 The unit is mm -3 The unit for the maximum diameter is mm.

[0019] Preferably, in step S22, the temperature rise at the tin bath outlet is ΔT3, where ΔT3 = 0.0033 × maximum thickness. 2 ×Maximum thickness / Maximum inclination angle of the tin bath outlet ramp line, where ΔT3 is in °C and 0.0033 is in °℃ / mm. 3 The unit for maximum thickness is mm, and the unit for maximum inclination angle of the tin bath outlet ramp is °.

[0020] Preferably, in step S22, when the foreign object moves to the optimal heating point, the solder bath outlet starts to heat up. The distance L2 from the optimal heating point to the solder bath outlet is L2 = ΔT3 ÷ heating rate × glass plate moving speed, where L2 is in meters, ΔT3 is in degrees Celsius, the heating rate is in degrees Celsius / min, and the glass plate moving speed is in meters / min.

[0021] Preferably, in steps S22 and S23, the height increase of the retaining wall and the curtain is ΔH2, where ΔH2 = maximum thickness + 5 - original height of the retaining wall and curtain, and the units of ΔH2, maximum thickness, 5, and original height of the retaining wall and curtain are mm.

[0022] Preferably, in step S23, the temperature rise at the tin bath outlet is ΔT4, where ΔT4 = 0.0033 × maximum thickness. 2 ×Maximum thickness / Maximum inclination angle of the tin bath outlet ramp line, where ΔT4 is in °C and 0.0033 is in °℃ / mm. 3 The unit for maximum thickness is mm; the unit for maximum inclination angle of the tin bath outlet ramp is °; maximum thickness / maximum inclination angle of the tin bath outlet ramp = 5.3 mm / °; glass plate thickness increase ΔD2 = 5.3 × 10 -7 ×Maximum thickness 4 The unit of ΔD2 is mm, 5.3 × 10⁻⁶. -7 The unit is mm -3 The unit for maximum thickness is mm.

[0023] Compared with the prior art, the present invention has the following beneficial effects: The present invention targets the tin bath section in the float glass forming process and adopts different control measures according to different foreign matter situations. It can detect foreign matter in a timely manner and prevent or quickly carry out emergency treatment, ultimately reducing the production losses caused by foreign matter in the glass plate. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the glass plate at the outlet of the tin bath.

[0025] Figure 2 This is a schematic diagram showing the positions of the endoscope and temperature sensor for the solder bath in the solder bath according to the present invention.

[0026] Figure 3 This is a schematic diagram of the foreign object on the glass plate in this invention.

[0027] In the diagram, 1 is the tin bath; 2 is the glass plate; 3 is the retaining wall; 4 is the curtain; 5 is the endoscope; 6 is the temperature sensor; and 7 is the foreign object. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0029] like Figure 2 As shown in the following embodiments, several endoscopes 5 for tin bath 1 are arranged at intervals in the tin bath 1, and the endoscopes 5 and temperature sensors 6 for tin bath 1 are arranged at the position where the glass plate 2 climbs at the outlet of tin bath 1, and silicon carbide rods are arranged at the outlet of tin bath 1 to heat the outlet of tin bath 1.

[0030] Example 1

[0031] In this embodiment, during the production of 0.7mm thick glass, an endoscope 5 detected a clump-shaped foreign object 7 with a maximum diameter of 25mm on the glass plate 2 inside the tin bath 1. The endoscope 5 also detected a maximum inclination angle of the ramp line at the outlet of the tin bath 1 ...

[0032] 1) Increase the outlet temperature of tin bath 1 by ΔT1 = (0.0023 × 25) 2 (×25÷6)℃≈6℃;

[0033] 2) The heating rate at the outlet of tin bath 1 is 20℃ / min, and the conveying speed of glass plate 2 is 800m / h = 13.3m / min. Therefore, the distance L1 from the outlet of tin bath 1 to the optimal heating point is (6÷20×13.3)m≈4m, that is, the heating starts when the foreign object 7 is 4m away from the outlet of tin bath 1.

[0034] 3) The original height of the barrier wall 3 and the curtain 4 from the glass plate 2 is 20mm. In this embodiment, the height of the foreign object 7 needs to be increased by ΔH1=(25+5-20)mm=10mm before it approaches the outlet of the tin bath 1. That is, the height of the barrier wall 3 and the curtain 4 from the glass plate 2 after the increase is 30mm.

[0035] 4) After the foreign object 7 passes through the outlet of the tin bath 1, restore the original production temperature and lower the height of the baffle wall 3 and the curtain 4 back to 20mm.

[0036] Example 2

[0037] In this embodiment, during the production of 0.7mm thick glass, an endoscope 5 detected a clump-shaped foreign object 7 with a maximum diameter of 40mm on the glass plate 2 within the tin bath 1. The endoscope 5 also detected a maximum inclination angle of the ramp line at the outlet of the tin bath 1 ...

[0038] 1) Increase the outlet temperature of tin bath 1 by ΔT2, where ΔT2 = (0.0023 × 36.6) 2 ×36.6÷6)℃≈18.8℃, where 36.6 is the maximum diameter value corresponding to the maximum diameter / maximum inclination angle of the tin bath outlet ramp line = 6.1;

[0039] 2) Adjust the thickness of glass plate 2 using the edge-pulling machine to ΔD1 + 0.7mm = (3.1 × 10⁻⁶ mm). -7 ×40 4+0.7)mm≈1.5mm;

[0040] 3) The original height of the barrier wall 3 and the curtain 4 from the glass plate 2 is 20mm. Therefore, in this embodiment, the height of the foreign object 7 needs to be increased by ΔH1=(40+5-20)mm=25mm before it approaches the outlet of the tin bath 1. That is, the height of the barrier wall 3 and the curtain 4 from the glass plate 2 after the increase is 45mm.

[0041] 4) After the foreign object 7 passes through the outlet of the tin bath 1, restore the original production temperature and the thickness of the glass plate 2, and lower the height of the baffle wall 3 and the curtain 4 back to 20mm.

[0042] Example 3

[0043] In this embodiment, during the production of 0.7mm thick glass, an endoscope 5 detected a strip-shaped foreign object 7 with a maximum thickness of 22mm on the glass plate 2 within the tin bath 1. The endoscope 5 also detected a maximum inclination angle of the ramp line at the outlet of the tin bath 1 ...

[0044] 1) Increase the outlet temperature of tin bath 1 by ΔT3 = 0.0033 × 22 2 ×22 / 6°=5.9℃;

[0045] 2) The heating rate at the outlet of tin bath 1 is 20℃ / min, and the conveying speed of glass plate 2 is 800m / h = 13.3m / min. Therefore, the distance L2 from the outlet of tin bath 1 to the optimal heating point is (5.9 ÷ 20 × 13.3)m ≈ 3.9m, that is, the heating starts when the foreign object 7 is 3.9m away from the outlet of tin bath 1.

[0046] 3) The original height of the barrier wall 3 and the curtain 4 from the glass plate 2 is 20mm. In this embodiment, the height of the foreign object 7 needs to be increased by ΔH2=(22+5-20)mm=7mm before it approaches the outlet of the tin bath 1. That is, the height of the barrier wall 3 and the curtain 4 from the glass plate 2 after the increase is 27mm.

[0047] 4) After the foreign object 7 passes through the outlet of the tin bath 1, restore the original production temperature and lower the height of the baffle wall 3 and the curtain 4 back to 20mm.

[0048] Example 4

[0049] In this embodiment, during the production of 0.7mm thick glass, an endoscope 5 detected a strip-shaped foreign object 7 with a maximum diameter of 33mm on the glass plate 2 within the tin bath 1. The endoscope 5 also detected a maximum inclination angle of the ramp line at the outlet of the tin bath 1 ...

[0050] 1) Increase the outlet temperature of tin bath 1 by ΔT4, where ΔT4 = (0.0033 × 31.8) 2 ×31.8÷6)℃≈17.7℃, where 31.8 is the maximum thickness value when the maximum thickness / maximum inclination angle of the tin bath outlet ramp line = 5.3;

[0051] 2) Adjust the thickness of glass plate 2 using the edge-pulling machine to ΔD2 + 0.7mm = (5.3 × 10) / 2. -7 ×33 4 +0.7)mm≈1.3mm;

[0052] 4) The original height of the barrier wall 3 and the curtain 4 from the glass plate 2 is 20mm. In this embodiment, the height of the foreign object 7 needs to be increased by ΔH2=(33+5-20)mm=18mm before it approaches the outlet of the tin bath 1. That is, the height of the barrier wall 3 and the curtain 4 from the glass plate 2 after the increase is 38mm.

[0053] 5) After the foreign object 7 passes through the outlet of the tin bath 1, restore the original production temperature and the thickness of the glass plate 2, and lower the height of the baffle wall 3 and the curtain 4 back to 20mm.

[0054] After different control measures were adopted in Examples 1-4, the occurrence of plate breakage accidents was avoided. Consequently, when the tin bath side seal was opened for plate cutting operation after a plate breakage accident, external gas was prevented from entering the tin bath through the side seal and contaminating the molten tin, which greatly reduced the impact of foreign objects on glass production.

Claims

1. A method for controlling foreign matter in a glass plate in an ultra-thin float glass tin bath, characterized in that, S1 When the foreign object (7) is in a clump When the first maximum diameter of the foreign object (7) is <20mm, no control is required; When the first maximum diameter of the foreign object (7) is ≥20mm and the maximum inclination angle of the first maximum diameter / glass plate (2) outlet ramp is <6.1mm / °, the outlet temperature of the tin bath (1) is increased and the height of the baffle wall (3) and the curtain (4) is increased; after the foreign object (7) passes through the outlet of the tin bath (1), the outlet temperature of the tin bath (1) and the height of the baffle wall (3) and the curtain (4) are restored to their original values. When the first maximum diameter of the foreign object (7) is ≥20mm and the first maximum diameter / the maximum slope angle of the glass plate (2) outlet is ≥6.1mm / °, the outlet temperature of the tin bath (1) is increased, the thickness of the glass plate (2) is increased, and the height of the baffle wall (3) and the curtain (4) is increased; after the foreign object (7) passes through the outlet of the tin bath (1), the outlet temperature of the tin bath (1), the thickness of the glass plate (2), and the height of the baffle wall (3) and the curtain (4) are restored to their original values; S2 When the foreign object (7) is in the form of a strip When the first maximum thickness of foreign object (7) is <18mm, no control is required; When the first maximum thickness of the foreign object (7) is ≥18mm and the first maximum thickness / maximum slope angle of the glass plate (2) outlet is <5.3mm / °, the outlet temperature of the tin bath (1) is increased and the height of the baffle wall (3) and the curtain (4) is increased; after the foreign object (7) passes through the outlet of the tin bath (1), the outlet temperature of the tin bath (1) is restored to the original temperature value, and the height of the baffle wall (3) and the curtain (4) is adjusted to the original height value; When the first maximum thickness of the foreign object (7) is ≥18mm and the first maximum thickness / the maximum slope angle of the glass plate (2) outlet is ≥5.3mm / °, the outlet temperature of the tin bath (1) is increased, the thickness of the glass plate (2) is increased, and the height of the baffle wall (3) and the curtain (4) is increased; after the foreign object (7) passes through the outlet of the tin bath (1), the outlet temperature of the tin bath (1), the thickness of the glass plate (2), and the height of the baffle wall (3) and the curtain (4) are restored to their original values; In step S12, the temperature rise of the tin bath (1) outlet is ΔT1, where ΔT1 = 0.0023 × the first maximum diameter. 2 × First maximum diameter / Tin bath (1) Maximum inclination angle of the outlet ramp line, where ΔT1 is in °C and 0.0023 is in °℃ / mm 3 The unit of the first maximum diameter is mm, and the unit of the maximum inclination angle of the tin bath (1) outlet ramp is °; In step S22, the temperature rise of the tin bath (1) outlet is ΔT3, where ΔT3 = 0.0033 × the first maximum thickness. 2 × First maximum thickness / Tin bath (1) Maximum inclination angle of the outlet ramp line, where ΔT3 is in °C and 0.0033 is in °℃ / mm 3 The unit for the first maximum thickness is mm, and the unit for the maximum inclination angle of the tin bath (1) outlet ramp is °.

2. The method for controlling foreign matter in the tin bath of ultra-thin float glass as described in claim 1, characterized in that, In step S12, when the foreign object (7) moves to the optimal heating point, the outlet of the tin bath (1) starts to heat up. The distance L1 from the outlet of the tin bath (1) to the optimal heating point is L1 = ΔT1 ÷ heating rate × glass plate (2) moving speed, where the unit of L1 is m, the unit of ΔT1 is ℃, the unit of heating rate is ℃ / min, and the unit of glass plate (2) moving speed is m / min.

3. The method for controlling foreign matter in the glass plate of an ultra-thin float glass tin bath as described in claim 1, characterized in that, In steps S12 and S13, the height increase of the retaining wall (3) and the curtain (4) is ΔH1, where ΔH1 = first maximum diameter + 5 - original height of retaining wall (3) and curtain (4), and the unit of ΔH1 is mm, the unit of the first maximum diameter is mm, the unit of 5 is mm, and the unit of the original height of retaining wall (3) and curtain (4) is mm.

4. The method for controlling foreign matter in the glass plate of an ultra-thin float glass tin bath as described in claim 1, characterized in that, In step S13, the temperature rise of the tin bath (1) outlet is ΔT2, where ΔT2 = 0.0023 × the second maximum diameter. 2 × second maximum diameter / tin bath (1) outlet ramp angle, where ΔT2 is in °C and 0.0023 is in °℃ / mm 3 The unit for the second largest diameter is mm, and the unit for the maximum inclination angle of the tin bath (1) outlet ramp is °. The second largest diameter / maximum inclination angle of the tin bath (1) outlet ramp = 6.1 mm / °; the thickness increase of the glass plate (2) ΔD1 = 3.1 × 10 -7 ×First maximum diameter 4 Where ΔD1 is in mm, 3.1 × 10⁻⁶ -7 The unit is mm -3 The unit for the first largest diameter is mm.

5. The method for controlling foreign matter in the tin bath of ultra-thin float glass as described in claim 1, characterized in that, In step S22, when the foreign object (7) moves to the optimal heating point, the outlet of the tin bath (1) starts to heat up. The distance from the optimal heating point to the outlet of the tin bath (1) is L2 = ΔT3 ÷ heating rate × glass plate (2) moving speed, where the unit of L2 is m, the unit of ΔT3 is ℃, the unit of heating rate is ℃ / min, and the unit of glass plate (2) moving speed is m / min.

6. The method for controlling foreign matter in the glass plate of an ultra-thin float glass tin bath as described in claim 1, characterized in that, In steps S22 and S23, the height increase of the retaining wall (3) and the curtain (4) is ΔH2, where ΔH2 = first maximum thickness + 5 - original height of retaining wall (3) and curtain (4), and the unit of ΔH2 is mm, the unit of the first maximum thickness is mm, the unit of 5 is mm, and the unit of the original height of retaining wall (3) and curtain (4) is mm.

7. The method for controlling foreign matter in the tin bath of ultra-thin float glass as described in claim 1, characterized in that, In step S23, the temperature rise of the tin bath (1) outlet is ΔT4, where ΔT4 = 0.0033 × the second maximum thickness. 2 × second maximum thickness / tin bath (1) outlet ramp angle, where ΔT4 is in °C and 0.0033 is in °℃ / mm 3 The unit for the second maximum thickness is mm, and the unit for the maximum inclination angle of the tin bath (1) outlet ramp is °. The second maximum thickness / maximum inclination angle of the tin bath (1) outlet ramp = 5.3 mm / °; the thickness increase of the glass plate (2) ΔD2 = 5.3 × 10 -7 ×First maximum thickness 4 The unit of ΔD2 is mm, 5.3 × 10⁻⁶. -7 The unit is mm -3 The unit for the first maximum thickness is mm.

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