A method and device for forming low-viscosity optical glass with large diameter

Abstract

The present invention is entitled "A method and device for forming large-diameter low-viscosity optical glass." It belongs to the field of optical glass forming technology. It mainly solves the problem of stripes in forming large-sized sheets of low-viscosity, easily crystallized optical glass. Its main features are: (1) the high-temperature glass liquid coming out of the furnace first flows through a cooling device to rapidly cool the high-temperature glass liquid to a temperature away from the crystallization temperature; (2) the glass liquid flowing out of the cooling device flows into a liquid storage buffer and is heated to a temperature above the transition temperature; (3) the glass liquid flowing out of the liquid storage buffer flows through a leaking molding tube to adjust the glass liquid temperature to the molding temperature range; and (4) the glass liquid flowing out of the leaking molding tube is drained into a mold for molding. The present invention has the characteristics of preventing the generation of tumbling molding stripes and being capable of mass production, and is mainly used for the production of large-sized sheets of low-viscosity, easily crystallized glass.

Description

Technical Field

[0001] The invention belongs to the technical field of optical glass molding, and in particular relates to a method and a device for molding low-viscosity optical glass with a large diameter. Background Art

[0002] Large-diameter optical glass is a high-quality optical material for the manufacture of reflectors and transmissive lenses in high-power laser systems. It is widely used in space telescopes, astronomical spectrographs, high-orbit imaging satellites, spacecraft reconnaissance and remote sensing systems, microsecond and sub-microsecond lithography lenses, and space-based laser weapons. With the application of high-refractive-index optical glass in these applications, the demand for large-diameter glass is increasing. This high-refractive-index optical glass, most of which contains multiple rare earth elements, is generally characterized by easy crystallization, high crystallization temperature, and low viscosity. When producing this type of glass, platinum barrels are generally used. The barrel nozzle is the outlet for the molten glass. The barrel nozzle should not be wrapped or insulated, as it is exposed to air and is exposed to low temperatures during the flow of the molten glass. To prevent crystallization, the temperature is generally above the crystallization temperature. However, these low-viscosity grades have high crystallization temperatures, resulting in low viscosity when the glass exits the barrel nozzle, which can easily cause tumbling streaks when entering the mold. Moreover, as the molding width and thickness increase, the tumbling stripes become more serious. In order to control the tumbling stripes, the continuous furnace production of this small viscosity grade generally reduces the molding width and thickness. If large-diameter products are produced, single-cup casting is often used, and then milling and grinding are used to remove the stripes, resulting in a high yield rate and low cost.

[0003] Patent document CN105948463B provides an optical glass edge drop forming device, including a bottom mold, a bracket, a rail trolley, a heating system and a preheating system. The heating system controls the temperature of the molding space, and the preheating system heats the bottom of the mold. The bracket is set on the rail trolley, and the bottom mold is set on the bracket. It also includes a frame and a plug. The bottom mold, frame and plug constitute a molding mold for optical glass.

[0004] Similarly, patent document CN113277713A provides a glass forming device and a forming method for large-diameter neodymium-doped phosphate laser glass, designed to ensure glass forming results while substantially avoiding surface cracks in the glass caused by moisture in the air. The glass forming device, by providing a cover plate, can largely seal the enclosed forming cavity. A protective gas conduit is provided to introduce protective gas into the cavity, driving out the air within and protecting the molten glass to be formed, preventing moisture in the air from re-entering the surface and subsurface layers of the glass in the form of OH-, thereby substantially avoiding the formation of surface cracks in the glass. Furthermore, by zigzagging the preheating section of the protective gas conduit along the cover plate, the heat transferred from the cover plate can be used to preheat the protective gas, preventing the excessively low protective gas temperature from significantly disturbing the forming temperature within the cavity and affecting the normal forming of the glass.

[0005] Patent document CN105948463B provides a method for forming the edge of large-diameter optical glass, which also highlights the solution to the problem of tumbling stripes, but is mainly used for single-cup production, not suitable for continuous production, and the operation is relatively complicated and the stability cannot be guaranteed. Patent document CN113277713A provides a glass forming device and a forming method for large-diameter neodymium-doped phosphate laser glass, which aims to ensure the glass forming effect while basically avoiding cracks on the glass surface caused by moisture in the air. The limitations are strong and cannot solve the tumbling stripes that appear in the continuous production process of low-viscosity grades that are easy to crystallize. The forming equipment and methods described in these two patents are difficult to solve the problem of large-diameter tumbling stripes in low-viscosity optical glass, which brings difficulties to production. Therefore, it is urgent to develop a forming device and method to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to solve the problem of rolling stripes occurring in large-diameter molding of low-viscosity glass during continuous production, and to design a large-diameter molding method and device for low-viscosity glass.

[0007] The technical problem to be solved by the present invention is: for glass with low viscosity that is easy to crystallize and has a high crystallization temperature, the glass liquid flowing out of the material pipe has a low viscosity due to its high temperature, and is prone to tumbling stripes when directly molded. The viscosity is often increased by reducing the discharge volume, and the width is reduced to prevent and reduce the occurrence of tumbling stripes. However, large-scale products often require milling to remove the stripes, resulting in a high yield and low cost. The present invention does not directly mold the glass liquid when it flows out of the leakage pipe at high temperature, but first rapidly cools the high-temperature glass liquid so that it quickly passes through the crystallization temperature zone to prevent the glass liquid from crystallizing at the discharge nozzle; then, the glass liquid is heated to a molding temperature zone below the glass crystallization temperature. By avoiding the method of increasing the viscosity due to glass crystallization, the low-viscosity glass brand is prevented from tumbling stripes when directly molded due to its low viscosity due to its high temperature. At the same time, the glass liquid with increased viscosity is matched with a flat and wide material pipe, which reduces the difficulty of producing large-diameter plates of low-viscosity glass brand and improves the yield.

[0008] The technical solution of the molding method of the present invention is: a large-diameter molding method for low-viscosity optical glass, which is used for large-diameter molding of low-viscosity optical glass in a continuous production process, and is characterized by comprising the following steps:

[0009] (1) The high-temperature molten glass coming out of the furnace is first passed through a cooling device to rapidly cool the high-temperature molten glass to a temperature away from the crystallization temperature;

[0010] (2) The glass liquid flowing out of the cooling device flows into the liquid storage buffer and is heated to a temperature above the transition temperature;

[0011] (3) The glass liquid flowing out of the liquid storage buffer tank flows through the leaking molding tube and the temperature of the glass liquid is adjusted to the molding temperature range;

[0012] (4) The glass liquid flowing out of the leaking molding tube is drained into the mold for molding.

[0013] The technical solution of the molding method of the present invention includes the following steps:

[0014] (1) The high-temperature glass liquid coming out of the furnace first flows through the cooling device to rapidly cool the high-temperature glass liquid to 100-600℃ below the crystallization temperature Lt;

[0015] (2) The glass liquid flowing out of the cooling device flows into the liquid storage buffer, and is heated to a temperature of 50-300°C above the transition temperature Ts;

[0016] (3) The glass liquid flowing out of the liquid storage buffer tank flows through the leakage forming tube, and the temperature of the glass liquid is adjusted to a temperature range of 50-300°C above Tg;

[0017] (4) The glass liquid flowing out of the leaking molding tube is drained into the mold for molding.

[0018] The technical solution of the molding device of the present invention is: a large-diameter molding device for low-viscosity optical glass, characterized in that: the device includes a leakage material injection pipe, a cooling device, a liquid storage buffer bin, a leakage material molding tube and a mold; wherein the leakage material injection pipe is connected to the discharge pipe of the glass melting furnace and is located above the cooling device; the cooling device is provided with a first temperature monitoring device for monitoring the liquid temperature; the liquid storage buffer bin is located below the outlet of the cooling device, and is provided with a first heating device and a second temperature monitoring device for monitoring the liquid temperature; the leakage material molding tube is connected to the outlet of the liquid storage buffer bin, and is provided with a second heating device and a fourth temperature monitoring device for monitoring the liquid temperature; the mold is located below the outlet of the leakage material molding tube.

[0019] The liquid storage buffer chamber described in the technical solution of the molding device of the present invention is provided with a third temperature monitoring device for monitoring the temperature above the liquid surface.

[0020] The cooling device described in the technical solution of the molding device of the present invention is a cooling trough with an inclined arc surface and shallow grooves; the cooling trough is composed of a cooling channel and baffles on both sides; the outlet of the leakage material injection pipe is located on the side of the cooling trough close to the high end.

[0021] The liquid storage buffer chamber described in the technical solution of the molding device of the present invention is composed of a funnel-shaped chamber body and a liquid storage buffer chamber cover; the liquid storage buffer chamber cover is provided with a liquid storage buffer chamber inlet that cooperates with the outflow end of the cooling trough; the outlet of the chamber body is flat and wide.

[0022] The leaking forming tube described in the technical solution of the forming device of the present invention is a straight flat wide tube, the upper end of which is fixedly connected to the outlet end of the bin body.

[0023] The first heating device described in the technical solution of the forming device of the present invention is composed of a first heating electrode sheet and a second heating electrode sheet, which are respectively arranged on two opposite sides of the warehouse body; the second heating device is composed of a third heating electrode sheet and a fourth heating electrode sheet, which are respectively arranged at the upper and lower ends of the relatively wide surface of the leakage forming tube.

[0024] The first temperature monitoring device described in the technical solution of the molding device of the present invention is composed of a first thermocouple and is arranged in the cooling tank; the second temperature monitoring device is composed of a second thermocouple and is arranged in the liquid storage buffer below the set liquid level; the fourth temperature monitoring device is composed of a fourth thermocouple and is arranged in the leaking molding tube; the cooling channel is built with foam copper; the cooling tank is made of stainless steel, aluminum bronze, platinum, gold, iridium or alloys of two or more thereof; the liquid storage buffer (6) is a fusion of one or more of platinum, gold and iridium materials.

[0025] The third temperature monitoring device described in the technical solution of the molding device of the present invention is composed of a third thermocouple, which is arranged in the liquid storage buffer chamber to set the glass liquid level warning line position.

[0026] The beneficial effects of the present invention are:

[0027] 1. Most brands of low-viscosity optical glass are prone to crystallization and have a high crystallization temperature, which is much higher than the temperature in the molding area. In order to prevent the glass liquid from crystallizing at the feed pipe mouth, the temperature of the glass liquid flowing out of the feed pipe mouth is generally kept higher than the crystallization temperature. The viscosity of the high-temperature glass liquid is low, and when it is formed, the viscosity changes greatly due to the large temperature difference, and it takes a long time to cool. During this molding process, tumbling stripes are likely to appear. The viscosity is often increased by reducing the discharge amount, and the width and thickness are reduced at the same time to allow the glass liquid to solidify as quickly as possible to prevent the occurrence of tumbling stripes. The present invention utilizes the characteristic that the crystallization temperature of low-viscosity optical glass is much higher than the molding temperature. The high-temperature glass liquid coming out of the furnace is not directly molded. Instead, before the glass liquid is molded, the high-temperature glass liquid flowing out of the furnace feed pipe is first quenched to allow it to quickly cross the crystallization temperature zone to prevent the glass liquid from crystallizing. The glass liquid is then heated to increase its temperature, allowing it to bypass the crystallization temperature and enter the molding temperature zone. At this time, the glass liquid has a high viscosity and is not easy to crystallize and tumbling stripes are unlikely to appear, so large-diameter glass can be produced.

[0028] 2. The funnel-shaped liquid storage chamber prevents dead corners that could cause glass stagnation. A heating electrode is installed to control the temperature of the glass liquid. Built-in glass liquid temperature detection thermocouples and liquid level over-limit thermocouples stabilize the glass liquid temperature and prevent overflow due to excessive liquid levels.

[0029] 3. The molding tube is different from the previous one. A wide flat tube is used instead of a round one. This can shorten the route of the glass liquid from the nozzle to the solidification process on both sides of the sheet, reduce the stroke difference between the two sides and the middle of the sheet during the molding process, enhance the consistency of the glass liquid molding history to reduce the temperature difference in the sheet molding area, and reduce the convection stripes caused by viscosity differences.

[0030] 4. The arc-shaped, smooth and shallow grooves in the cooling tank reduce the local retention of the glass liquid, allowing the glass liquid to cool gradually, reducing reflux and improving cooling efficiency. A glass liquid temperature detection thermocouple is installed inside to stabilize the cooling effect.

[0031] 5. The cooling channel hole below the cooling tank is designed to be made of foam copper, which can increase the heat dissipation area of the channel hole, reduce the amount of cooling medium, and improve the cooling effect and the utilization rate of the cooling medium.

[0032] 6. The optical glass of the present invention can be used to form large-diameter crown, flint, lanthanide, fluorophosphorus and other types of optical glasses, and can solve the problem of forming stripes in lanthanide, fluorophosphorus and other types of optical glasses with low viscosity and easy crystallization.

[0033] The invention has the characteristics of preventing the generation of tumbling forming stripes and being capable of batch production, and is mainly used for the production of large-size plates of low-viscosity and easy-crystallization glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a structural schematic diagram of a low-viscosity optical glass large-diameter molding device according to the present invention.

[0035] Figure 2 .It is a cross-sectional schematic diagram of a large-diameter forming device for low-viscosity optical glass according to the present invention.

[0036] Explanation of symbols: 1-cooling trough; 2-leakage material injection pipe; 3-first thermocouple; 4-glass liquid; 5-liquid storage buffer chamber cover; 6-liquid storage buffer chamber; 7-first heating electrode sheet; 8-second heating electrode sheet; 9-third heating electrode sheet; 10-fourth heating electrode sheet; 11-leakage material forming tube; 12-liquid storage buffer chamber entrance; 13-second thermocouple; 14-third thermocouple; 15-cooling channel; 16-fourth thermocouple. DETAILED DESCRIPTION

[0037] The present invention will be further described below with reference to the accompanying drawings.

[0038] like Figure 1 、 Figure 2As shown. The present invention provides a large-diameter forming device for low-viscosity optical glass, comprising a leaking material injection pipe 2, a cooling trough 1, a liquid storage buffer 6, a leaking material forming pipe 11, and a mold (not shown). The cooling trough 1 is in the shape of a shallow, inclined arc-shaped groove, consisting of a cooling channel 15 at the lower end and baffles on both sides. The cooling channel 15 is made of aluminum bronze, but can also be made of stainless steel, platinum, gold, iridium, or alloys of two or more thereof. The cooling effect can be controlled by adjusting the flow rate of the cooling medium in the cooling channel 15. Filling the cooling channel 15 with foamed copper can enhance the cooling effect and improve the cooling efficiency. The cooling medium is air, but can also be nitrogen or water as needed. The leakage injection pipe 2 is connected to the leakage pipe of the furnace. The outlet of the leakage injection pipe 2 is located on the side close to the high end of the cooling tank 1. The glass liquid is introduced from the furnace into the arc-shaped cooling tank 1. A first thermocouple 3 is set in the cooling tank 1 to detect the cooling degree of the glass liquid 4. The high-temperature glass liquid 4 introduced from the furnace is rapidly cooled to 100-600°C below the crystallization temperature Lt through the cooling tank 1. At this time, the glass liquid 4 is far away from the crystallization temperature Lt area and is difficult to crystallize, and has a certain fluidity. The liquid storage buffer tank 6 consists of a funnel-shaped tank body and a lid 5. Made of platinum, it can also be made of gold, iridium, or a combination of these materials. The funnel-shaped tank body prevents dead corners that could cause glass stagnation. The lid 5 is equipped with a reservoir inlet 12 that mates with the outflow end of the cooling trough 1. The tank body's outlet is flat and wide. As the amount of glass 4 injected into the cooling trough 1 via the leaking injection pipe 2 increases, the cooled glass 4 flows through the reservoir inlet 12 into the liquid storage buffer tank 6. The liquid storage buffer tank 6 is equipped with a first heating electrode 7 and a second heating electrode 8 to heat the liquid storage buffer tank 6. A second thermocouple 13 and a third thermocouple 14 are also located within the liquid storage buffer tank 6. The second thermocouple 13 is located below the set liquid level in the liquid storage buffer tank 6 to control the temperature of the glass molten in the liquid storage buffer tank 6 to 100-500°C below the crystallization temperature Lt. A third thermocouple 14 is positioned within the liquid storage buffer chamber 6 to define a glass level warning line, enabling the temperature control alarm to function as a liquid level overrun alarm, preventing overflow of the glass within the liquid storage buffer chamber 6. The liquid storage buffer chamber 6 is also provided with a liquid storage buffer chamber cover 5, which maintains the stability and uniformity of the glass temperature field within the chamber while reducing component volatilization.

[0039] A wide and flat leakage forming tube 11 is provided at the lower end of the liquid storage buffer bin 6. A pair of heating electrode sheets are provided above and below the leakage forming tube 11, namely, a third heating electrode sheet 9 and a fourth heating electrode sheet 10. A fourth thermocouple 16 is provided in the middle, which can adjust the glass liquid temperature to control the forming flow rate. The current passing through the third heating electrode sheet 9 and the fourth heating electrode sheet 10 heats the leakage forming tube 11 so that the glass liquid at its outlet reaches a temperature above Tg in the range of 50-300°C so that it can be injected into the forming mold. In the appropriate temperature range, the total amount of glass liquid flowing into and out of the liquid storage buffer bin reaches a balance, thereby achieving a stable temperature field cache space.

[0040] The following is a further explanation of the operation steps using specific brands.

[0041] H-ZLaF7* is a brand of optical glass containing rare earth and heavy metals, characterized by low viscosity and easy crystallization. Its crystallization temperature reaches as high as 1310°C, while its molding temperature is around 660°C. During production, the melt output can reach over 700 kg / day. Because the crystallization temperature is so high, with a 650°C difference from the molding temperature, the glass nozzle temperature must be kept above 1330°C to prevent crystallization. The viscosity of the glass melt at the discharge nozzle is extremely low, and the temperature must be lowered to around 650°C before the glass begins to solidify and set. This significant temperature difference requires significant cooling time and space, making it prone to tumbling streaks within this temperature range. To prevent these streaks, the output is often reduced to below 500 kg / day, and the molding width is reduced by 80 mm from the standard 160 mm. Even with these reductions in output and molding width, tumbling streaks are still unavoidable, especially in production of thicknesses above 20 mm, where the milling loss due to streaks is at least 30%, resulting in significant cost losses. The following describes the process steps of the molding device of the present invention by taking the production of large-size glass strips of 300 mm in width and 50 mm in thickness as an example.

[0042] 1. According to Figure 1 The molding device shown in the figure has a cooling trough 1 measuring 120 mm wide and 200 mm long, with a maximum depth of 50 mm, allowing the glass melt to flow in higher than the outflow side. Based on the molding material volume and specifications, the liquid storage buffer chamber 6 is designed to be funnel-shaped, with a length of 250 mm, a width of 200 mm, and a depth of 150 mm. First and second heating electrode sheets 7 and 8 are mounted on either side, and a liquid storage buffer chamber cover 5 with a liquid storage buffer chamber inlet 12 is located on top. A flat, wide molding leaking pipe 11 is located at the lower end of the liquid storage buffer chamber 6. The molding leaking pipe 11 has a cross-sectional width of 200 mm and a thickness of 10 mm. The length is designed to be 350 mm based on the required height of the on-site space. Third and fourth heating electrode sheets 9 and 10 for heating, as well as a fourth thermocouple 16, are located at the upper and lower ends of the molding leaking pipe 11. By adjusting the input current of the third and fourth heating electrode sheets 9 and 10, the temperature and viscosity within the molding leaking pipe 11 are adjusted to control the flow of the glass melt within the pipe.

[0043] 2. First, connect the leakage injection pipe 2 to the glass liquid outlet of the furnace, control the glass liquid at the furnace outlet to be above 1330℃, and introduce the glass liquid into one side of the cooling tank 1 through the leakage injection pipe 2 (such as Figure 1 As the amount of molten glass flowing into the cooling tank 1 increases, the molten glass 4 fills the cooling tank 1 and overflows from the other side. The position and parallelism of the cooling tank 1 are adjusted so that the molten glass is evenly distributed at the outlet of the cooling tank 1 and flows into the molten glass buffer tank 6 from the molten glass buffer tank inlet 12. The molten glass is then transported to the forming mold through the forming leakage pipe 11 for forming the lead.

[0044] 3. After the lead forming specifications and discharge volume are close to the target, adjust the amount of glass liquid from the melting furnace flowing into the leakage injection pipe 2 so that the glass liquid in the liquid storage buffer bin 6 reaches the appropriate liquid level position.

[0045] 4. When the glass liquid in the liquid storage buffer bin 6 reaches an appropriate liquid level, cooling air is introduced into the cooling channel at the bottom of the cooling tank 1. The amount of cooling air is adjusted so that the temperature of the glass liquid 4 in the cooling tank 1 reaches a preset range. Here, the temperature is set to 750±30℃ based on the H-ZLaF7* crystallization temperature and discharge amount parameters.

[0046] 5. After the temperature in the cooling tank 1 reaches stability, adjust the current of the heating electrodes on both sides of the liquid storage buffer tank 6 to make the glass liquid temperature in the liquid storage buffer tank 6 reach the set temperature of 850±20℃.

[0047] 6. After the temperature of the glass liquid in the liquid storage buffer tank 6 is stabilized, adjust the current of the third heating electrode piece 9 and the fourth heating electrode piece 10 of the leaking material forming tube 11 so that the temperature of the fourth thermocouple 16 in the leaking material forming tube 11 reaches the set temperature of 800±50℃.

[0048] 7. The glass liquid in the liquid storage buffer 6 is much hotter than the ambient temperature. This characteristic can be exploited to implement a temperature-controlled alarm for liquid level overruns. The method involves first setting a glass level warning line in the liquid storage buffer 6 and lowering the end of the fourth thermocouple 14 to the liquid level warning line. When the glass level reaches the warning line, it contacts the detection thermocouple, triggering a temperature limit alarm. This allows for a liquid level overrun alarm using both the thermocouple and the temperature controller.

[0049] 8. When the forming thickness needs to be adjusted, it can be achieved by adjusting the amount of glass liquid supplied by the melting furnace to the leakage injection pipe 2, the glass liquid level in the liquid storage buffer bin 6, and the temperature of the leakage forming pipe 11. Many links cooperate with each other to achieve this.

[0050] 9. If some glass is prone to tumbling streaks or convection streaks, the temperature of the forming tube 11 can be further reduced.

Claims

1. A method for forming large-diameter low-viscosity optical glass, which is used for forming large-size low-viscosity optical glass sheets in a continuous production process, characterized in that The following steps are involved: (1) The high-temperature molten glass from the melting furnace is first passed through a cooling device to rapidly cool the high-temperature molten glass to a temperature away from the crystallization temperature; the cooling device is a cooling trough with an inclined arc surface and shallow grooves, which is composed of a cooling channel and baffles on both sides; (2) The glass liquid flowing out of the cooling device flows into a liquid storage buffer chamber, and is heated to raise the temperature of the glass liquid to above the transition temperature; the outlet of the liquid storage buffer chamber is flat and wide; (3) The glass liquid flowing out of the liquid storage buffer tank flows through the leakage forming tube, and the temperature of the glass liquid is adjusted to a temperature range of 50-300° C. above Tg; the leakage forming tube is a straight flat wide tube; (4) The glass liquid flowing out of the leaking molding tube is drained into the mold for molding.

2. A method for forming a large-diameter low-viscosity optical glass according to claim 1, characterized in that The following steps are involved: (1) The high-temperature glass liquid coming out of the furnace first flows through the cooling device to rapidly cool the high-temperature glass liquid to 100-600℃ below the crystallization temperature Lt; (2) The glass liquid flowing out of the cooling device flows into the liquid storage buffer, and is heated to a temperature of 50-300°C above the transition temperature Ts; (3) The glass liquid flowing out of the liquid storage buffer tank flows through the leaking molding tube and the temperature of the glass liquid is adjusted to the molding temperature range; (4) The glass liquid flowing out of the leaking molding tube is drained into the mold for molding.

3. A low-viscosity optical glass large-diameter forming device, used for forming low-viscosity optical glass large-size sheets in a continuous production process, characterized by: The device comprises a leaking material injection pipe (2), a cooling device, a liquid storage buffer chamber (6), a leaking material forming pipe (11) and a mold; wherein the leaking material injection pipe (2) is connected to the discharge pipe of the glass melting furnace and is located above the cooling device; the cooling device is a cooling trough (1) in the form of an inclined arc-shaped shallow groove, which is composed of a cooling channel (15) and baffles on both sides, and is provided with a first temperature monitoring device for monitoring the liquid temperature; the liquid storage buffer chamber (6) is located below the outlet of the cooling device, the outlet is flat and wide, and is provided with a first heating device and a second temperature monitoring device for monitoring the liquid temperature; the leaking material forming pipe (11) is a straight flat and wide pipe, connected to the outlet of the liquid storage buffer chamber (6), and is provided with a second heating device and a fourth temperature monitoring device for monitoring the liquid temperature; the mold is located below the outlet of the leaking material forming pipe (11).

4. The low-viscosity optical glass large-diameter forming device according to claim 3, characterized in that: The liquid storage buffer chamber (6) is provided with a third temperature monitoring device for monitoring the temperature above the liquid surface.

5. A low-viscosity optical glass large-diameter forming device according to claim 3 or 4, characterized in that: The outlet of the leakage material injection pipe (2) is located on the side close to the high end in the cooling tank (1).

6. The low-viscosity optical glass large-diameter forming device according to claim 5, characterized in that: The liquid storage buffer chamber (6) is composed of a funnel-shaped chamber body and a liquid storage buffer chamber cover (5); the liquid storage buffer chamber cover (5) is provided with a liquid storage buffer chamber inlet (12) that cooperates with the outflow end of the cooling trough (1).

7. The low-viscosity optical glass large-diameter forming device according to claim 6, characterized in that: The upper end of the leaking material forming tube (11) is fixedly connected to the outlet end of the bin body.

8. A low-viscosity optical glass large-diameter forming device according to claim 6 or 7, characterized in that: The first heating device is composed of a first heating electrode sheet (7) and a second heating electrode sheet (8), which are respectively arranged on two opposite sides of the bin body; the second heating device is composed of a third heating electrode sheet (9) and a fourth heating electrode sheet (10), which are respectively arranged at the upper end and the lower end of the relatively wide surface of the leaking forming tube (11).

9. The low-viscosity optical glass large-diameter forming device according to claim 8, characterized in that: The first temperature monitoring device is composed of a first thermocouple (3) and is arranged in the cooling tank (1); the second temperature monitoring device is composed of a second thermocouple (13) and is arranged in the liquid storage buffer chamber (6) below the set liquid level; the fourth temperature monitoring device is composed of a fourth thermocouple (16) and is arranged in the leaking material forming tube (11); the cooling channel (15) is built with foam copper; the cooling tank (1) is made of stainless steel, aluminum bronze, platinum, gold, iridium or alloys of two or more thereof; the liquid storage buffer chamber (6) is a fusion of one or more of platinum, gold and iridium materials.

10. The low-viscosity optical glass large-diameter forming device according to claim 4, characterized in that: The third temperature monitoring device is composed of a third thermocouple (14) and is arranged in the liquid storage buffer chamber (6) to set the glass liquid level warning line position.

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