WO2013024649A1

WO2013024649A1 - Float glass production device, and float glass production method employing same

Info

Publication number: WO2013024649A1
Application number: PCT/JP2012/067624
Authority: WO
Inventors: 康裕楠木; 信之伴; 丈宜三浦
Original assignee: 旭硝子株式会社
Priority date: 2011-08-16
Filing date: 2012-07-10
Publication date: 2013-02-21
Also published as: TW201309606A; KR101944563B1; KR20140057202A; CN103635437B; JPWO2013024649A1; CN103635437A

Abstract

[Solution] A float glass production device having a water-cooled tube for cooling a bottom casing that covers the bottom part of the bottom brick of a bath filled with molten tin, the float glass production device being characterized in that, at least at the joint locations of the bottom brick, the water-cooled tube is furnished to the bottom part of the bottom casing while a heat transfer material is interposed therebetween, the heat transfer material having hardness of 10-50 (Asker C) and a heat transfer coefficient λ/d of 0.2 × 10³-1.6 × 10³W/(m² • K), where the thickness d is 0.001-0.05 m; and a float glass production method employing the same.

Description

Float glass manufacturing apparatus and float glass manufacturing method using the same

The present invention relates to a float glass manufacturing apparatus and a float glass manufacturing method using the same.

The float process is widely known as a method for producing flat glass, and in recent years, it has been used for various purposes such as display glass in addition to conventional architectural window glass and automotive window glass. Yes.

The production of plate glass by the float process is carried out using a float bath with molten tin. Specifically, molten glass is poured onto the molten tin from the upstream side, and is formed into a desired thickness and width while being guided to a strip-shaped glass ribbon in a forming region disposed on the downstream side.

As described above, the float bath needs to hold molten tin at 500 ° C. or higher inside. For this reason, the float bath has a configuration in which the inner surface of the bottom casing constituting the lower portion thereof is lined with a fire-resistant bottom brick, and molten tin is filled therein. However, depending on temperature conditions and the like, molten tin can enter the seam of the refractory bottom brick and reach the bottom casing portion. As described above, when the bottom casing and the molten tin come into contact with each other, a reaction occurs and the bottom casing is damaged. In order to avoid such a situation, the lower part of the refractory block needs to be kept below the melting temperature of tin (231.9 ° C.).

For this reason, conventionally, a method of cooling by blowing air on the outer surface of the bottom casing has been employed (Patent Document 1).

However, cooling with air blows air over the entire device and cools it uniformly, so this cannot be resolved if there is a temperature difference in the bottom casing. Also, depending on the location, the air did not reach sufficiently, resulting in further temperature variations within the bottom casing. Furthermore, since the air temperature of the refrigerant fluctuates due to changes in the outside air temperature, it has been difficult to control to a stable temperature.

And it is known that when temperature variation or fluctuation occurs in the bottom casing or the like in this way, gas is precipitated and released from the molten tin, and the gas comes into contact with the glass flowing on the molten tin. The problem of generating defects in the glass has occurred (Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2003-261339 Japanese Patent Publication No. 4-29614

The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a float glass manufacturing apparatus capable of uniformly cooling the bottom casing below the float bath, and a float glass manufacturing method using the same.

In order to solve the above problems, the present invention provides a float glass manufacturing apparatus having a water cooling pipe for cooling a bottom casing covering a bottom brick bottom of a bathtub where molten tin is provided, wherein the water cooling pipe is at least of the bottom brick. A heat transfer material is provided below the bottom casing along the joint position. The heat transfer material has a hardness of 10 to 50 (Asker C) and a heat transfer coefficient λ / d of 0.2. There is provided a float glass manufacturing apparatus characterized in that the thickness d is 0.001 to 0.05 m, and × 10 ³ to 1.6 × 10 ³ W / (m ² · K).

The present invention can make the temperature of the bottom casing more uniform by adding a water cooling mechanism to at least a portion of the bottom casing of the float glass manufacturing apparatus corresponding to the joints of the bottom brick disposed on the top casing. . Furthermore, it becomes possible to reduce or prevent the precipitation and generation of gas from molten tin.

Cross section of float glass manufacturing equipment Horizontal sectional view of float glass manufacturing equipment Explanatory drawing of the relationship between the distance from the joint part of a brick, and the cooling effect in the float glass manufacturing apparatus which concerns on this invention Explanatory drawing about the simulation model of FIG. 2A Explanatory drawing of the relationship between the heat transfer rate of the heat transfer material and the cooling effect in the float glass manufacturing apparatus according to the present invention. Explanatory drawing about the structural example of the water cooling tube and heat-transfer material which concern on this invention Explanatory drawing about the structural example of the water cooling tube and heat-transfer material which concern on this invention Explanatory drawing about the structural example of the water cooling tube and heat-transfer material which concern on this invention Explanatory drawing about the structural example of the water cooling tube and heat-transfer material which concern on this invention Explanatory drawing about the structural example of the water cooling tube and heat-transfer material which concern on this invention Explanatory drawing about the structural example of the water cooling tube and heat-transfer material which concern on this invention Explanatory drawing about the structural example of the water cooling tube and heat-transfer material which concern on this invention Explanatory drawing about the structural example of the water cooling tube and heat-transfer material which concern on this invention Explanatory drawing about the structural example of the water cooling tube and heat-transfer material which concern on this invention

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and the following embodiments are not departed from the scope of the present invention. Various modifications and substitutions can be made.

First, a float glass manufacturing apparatus will be described with reference to FIGS. 1A and 1B. In addition, FIG. 1A and FIG. 1B demonstrate the outline of a common float glass manufacturing apparatus, and this invention is not limited to the apparatus which concerns.

FIG. 1A shows a cross-sectional view of a float glass manufacturing apparatus.

As shown in FIG. 1A, the float glass manufacturing apparatus has a structure in which a float bath roof 11 is arranged at the upper part and a float bathtub 12 is arranged at the lower part, and these are surrounded by these. In the float bathtub 12, molten tin 13 is provided, and the molten glass introduced from the upstream side of the apparatus on the molten tin 13 is formed into a glass ribbon 14 having a predetermined thickness as it goes downstream of the apparatus. The

Here, the molten tin 13 has an appropriate depth and temperature so that the float process can be performed, and the inside of the float glass manufacturing apparatus is maintained in a reducing atmosphere so that the molten tin is not oxidized.

Further, since the float bathtub 12 needs to have a structure capable of withstanding the heat from the molten tin 13, a bottom brick 15 (hereinafter simply referred to as “brick”) is spread on the surface in contact with the molten tin. The outer casing is covered with the bottom casing 16.

Next, FIG. 1B shows a horizontal sectional view of the float glass manufacturing apparatus. This shows a cross-sectional view taken along line AA ′ in FIG. 1A. The molten glass flow introduced from the left side in FIG. 1B is pushed from above by a top roll (rotating roll with grooves) 17 as shown in the figure, for example, to prevent the reduction of the glass ribbon width and adjust the thickness. Thus, in the float glass manufacturing apparatus, the molten glass from the melting kiln is formed on the molten tin into a glass ribbon 14 having a predetermined thickness, and is arranged on the right side in the figure, which is the next step. It is drawn out to a slow cooling kiln (not shown).

And this invention is characterized by having a predetermined | prescribed structure, such as a water-cooled pipe | tube, in a bottom casing part in such a float glass manufacturing apparatus.

Here, FIGS. 4A to 4I described later are enlarged views of the periphery of the bottom casing portion of the float glass manufacturing apparatus. That is, for example, the part surrounded by the dotted line in FIG. 1A is enlarged, and in the float glass manufacturing apparatus of the present invention, the cross section of the part where the water-cooled tube is arranged via the heat transfer material at the joint position of the brick Is schematically shown. Here, taking FIG. 4C as an example, the structure of the peripheral portion of the bottom casing will be described. In the figure, the brick 15 is at the top, and the bottom casing 16, the heat transfer material 18, and the water cooling pipe 19 are arranged in that order. It is. Although not shown in FIG. 4C, molten tin 13 is disposed on the brick 15. Further, the heat transfer material 18 and the water cooling pipe 19 are arranged along the joint position of the brick 15. Even when there was a gap between the brick and the bottom casing (not shown), a simulation described later was performed assuming that the gap was filled with tin around the joint. In FIG. 4C, the two bricks 15 and the joint positions that are the contact portions thereof are schematically shown. However, in the float glass manufacturing apparatus, many bricks 15 are arranged in the bottom casing 16 as described above. Yes. And in this invention, it has the above structures in the joint part of each brick at least. By having such a configuration, it is possible to locally cool a portion of the bottom casing 16 corresponding to the brick joint where the temperature is likely to rise. For this reason, since the temperature gradient in the bottom casing 16 is eased and eliminated, it becomes possible to obtain a substantially uniform temperature as a whole.

Next, each member constituting the periphery of the brick joint will be described below.

Here, the brick 15 is designed and arranged so that, when the float glass manufacturing apparatus is in steady operation, the brick 15 expands due to heat in the apparatus such as molten tin 13 so that no gap is generated between the bricks.

Any material can be used for the bottom casing 16 as long as it has heat resistance and can maintain airtightness in the apparatus. However, in view of heat resistance, ease of processing, and cost, soft iron or stainless steel can be used. It is preferable that

The heat transfer material 18 has a hardness of 10 to 50 (Asker C), a heat transfer coefficient λ / d = 0.2 × 10 ³ to 1.6 × 10 ³ W / (m ² · K), and a thickness d In the range of 0.001 to 0.05 m. In this case, the thermal conductivity λ is in the range of 0.2 to 80 W / (m · K), more preferably in the range of 0.2 to 48 W / (m · K). In particular, the range is preferably 0.2 to 32 W / (m · K).

First, the heat transfer material 18 functions as a filler for increasing the adhesion between the two members in addition to the function of transferring the heat from the outer surface of the bottom casing 16 to the cooling water in the water cooling pipe 19. It functions as a cushioning material that prevents damage to the device due to thermal stress during startup and shutdown. Therefore, when it is necessary to select a material having a hardness that matches the above-mentioned purpose, if the hardness is higher than 50 (Asker C), the shape is difficult to deform, so that it is sufficient as a filler or cushioning material. Since it does not function and the adhesiveness of both members deteriorates, it is not preferable. Moreover, since it becomes difficult to construct when the hardness is lower than 10 (Asker C), it is not preferable. For this reason, the hardness having the above range was used.

Here, FIG. 2A shows a simulation result of a temperature distribution state around the brick joint portion when the heat transfer coefficient (H) of the heat transfer material is changed. At this time, calculation is performed using the structure shown in FIG. 4C as a model, and an enlarged view thereof is shown in FIG. 2B. 2A indicates the horizontal distance from the brick joint as indicated by the arrow (X) in FIG. 2B. And the Y-axis has shown the temperature distribution of the outer surface of the bottom casing compared with the case of only air cooling, ie, the bottom casing surface by the side which has arrange | positioned the heat-transfer material. Here, it shows as a temperature difference with the case of only air cooling. FIG. 3 shows the temperature change of the joint portion when the heat transfer coefficient of the heat transfer material is changed as a temperature difference from the case of only air cooling.

The simulation was performed by the finite element method. As concrete conditions, molten tin 13 is in a steady state of 1200 ° C. and water in a water-cooled tube is in a steady state of 30 ° C., and brick 15 has a thermal conductivity of 1.4 W / (main component of SiO ₂ and Al ₂ O ₃ as main components. m · K) bricks were used, and the bottom surface of the molten tin was separated from the bottom casing by 300 mm. The width of the water-cooled tube is 48 mm, and cooling is performed at the same temperature (30 ° C.) by 24 mm from the joint part to the left and right. In addition, cooling by air cooling is also performed.

As shown in FIG. 2A, by setting the heat transfer coefficient to 0.2 × 10 ³ to 1.6 × 10 ³ W / (m ² · K), it is 10 centering on the joint as compared with the case of only air cooling. C. to 40.degree. C. can be cooled. Normally, brick joints tend to transfer heat more easily than other parts (the brick body), so the corresponding bottom casing part tends to be locally hot at about 10-40 ° C. There is. This is probably because part of the molten tin flows in depending on the case or heat is easily transferred from a minute gap between the bricks. Therefore, by cooling in the temperature range corresponding to this, the temperature difference in the bottom casing can be eliminated and the temperature can be made uniform as a whole.

If the heat transfer coefficient is outside the range of 0.2 × 10 ³ to 1.6 × 10 ³ W / (m ² · K), cooling is not sufficient or excessively cooled. If the cooling is not sufficient, the object of the present invention for making the temperature of the bottom casing uniform cannot be sufficiently achieved. Moreover, when it cools too much, the temperature of a joint part will become temperature lower than another part, and since temperature distribution may reverse, it is unpreferable.

FIG. 3 shows the relationship between the heat transfer coefficient and the cooling effect of the joint part of the brick in the simulation. The Y axis shows the temperature difference from the case of only air cooling. The temperature is the temperature of the outer surface portion of the bottom casing corresponding to the joint portion of the brick, that is, the portion between the bottom casing and the heat transfer material. This shows that the higher the heat transfer coefficient, the higher the cooling effect. As a reference example, an example in which the heat transfer coefficient is 0.1 × 10 ³ W / (m ² · K) has been shown, but in such a case, the cooling effect is lower than in the case of air cooling. This is because not only the joint portion could not be cooled due to the low heat transfer coefficient but also a heat insulating effect, and it seems that the temperature rose. In the case of 0.2 × 10 ³ to 1.6 × 10 ³ W / (m ² · K) where the heat transfer rate satisfies the provisions of the present invention, −10 compared to the case of only air cooling It can be seen that the cooling effect of ˜−40 ° C. is exhibited and the object of the present invention can be achieved.

As described above, the temperature of the bottom casing, which is the object of the present invention, can be uniformly cooled by selecting the heat transfer coefficient within the above range.

Here, the thickness and heat conductivity of the heat transfer material 18 can be selected in order to set the heat transfer coefficient within the range. However, as described above, the heat transfer material plays a role as a heat transfer medium for transferring heat and a role as a buffer material and a filler between the water-cooled tube and the bottom casing. For this reason, if the thickness is too thin, it cannot play a role as a sufficient cushioning material or filler, and if it is too thick, it lacks stability as a device and is easily affected by outside air or the like. In order to avoid such a problem, the thickness of the heat transfer material is preferably in the range of 0.001 m to 0.05 m, particularly preferably 0.001 to 0.03 m, 0.001 to More preferably, it is 0.02 m. In accordance with this, it is necessary to select a heat transfer material having a heat conductivity λ that takes the range of the heat transfer coefficient, but it is preferably 0.2 to 80 W / (m · K). 0.2 to 48 W / (m · K) is more preferable. In particular, it is preferably 0.2 to 32 W / (m · K).

The heat transfer material is not particularly limited as long as it satisfies the above conditions of hardness, heat transfer rate, heat conductivity, and thickness, and any material can be used. Specific examples include silicone resin, cement (including Portland cement, mixed cement, alumina cement), silicon cement, stainless wool, stainless felt, carbon wool, carbon felt, carbon cement, Dunseal (registered trademark), and the like. it can. As used herein, the term “silicone resin” has a broad meaning and includes silicone rubber and the like. In particular, the heat transfer material is preferably made of silicone resin or cement (including Portland cement, mixed cement, and alumina cement) from the viewpoint of easy availability and handling.

Further, it is preferable that the heat transfer material 18 has the same width as the water-cooled tube 19 or a width larger than that. As described above, the heat transfer material 18 has a function as a heat medium for assisting heat transfer between the bottom casing 16 and the water-cooled pipe 19, and functions as a filler and a buffer material for improving adhesion. It is because it is doing. For this reason, it is preferable to arrange so that at least the entire range of the water-cooled tube can be covered. Therefore, considering the cooling capacity and the like as will be described later, the width of the water cooling tube 19 is preferably 20 to 200 mm, more preferably 40 to 100 mm, and the width of the heat transfer material 18 is adjusted accordingly. The thickness is preferably 20 to 200 mm, more preferably 40 to 100 mm.

Furthermore, the shape of the heat transfer material is not particularly limited as long as it is configured so that the water-cooled tube is fixed to the surface of the bottom casing and heat conduction can be performed between the two. As a specific example, as shown in FIGS. 4A to 4C, 4F, and 4H, the cross section can be provided in a substantially rectangular shape, or in FIGS. 4D, 4E, 4G, and 4I. As shown, the cross section can be provided in a substantially trapezoidal shape.

Next, the shape and the configuration of the water-cooled pipe 19 are not limited as long as the water-cooled pipe 19 is arranged along the joint position of the bottom brick.

Examples of the shape of the water-cooled tube include a square tube as shown in FIGS. 4A, 4C, 4D, 4F, and 4H, and a circular tube as shown in FIGS. 4B, 4E, 4G, and 4I. It is done. In addition, about the square tube, it is not specifically limited as the cross-sectional shape, Various shapes, such as a square and a rectangle, can be taken. Similarly, the cross-sectional shape of the circular tube is not limited, and various shapes such as a perfect circle and an ellipse can be taken.

4A, 4B, and 4F to 4I can be provided with a plurality of water-cooled pipes centering on the joint portion, or as shown in FIGS. 4C to 4E. Large water-cooled tubes can also be provided.

Further, when a plurality of water cooling tubes are provided, a plurality of water cooling tubes can be provided on one heat transfer material as shown in FIGS. 4A and 4B. However, as shown in FIGS. 4F to 4I, each water cooling tube is provided. A heat transfer material can also be provided for each tube.

When a plurality of water-cooled tubes are arranged at intervals, as shown in FIGS. 4H and 4I, an air-cooling nozzle 20 is provided between the water-cooled tubes and used together with air cooling to enhance the cooling effect. You can also.

And the size of the water-cooled tube is not particularly limited. However, in order to arrange at a position corresponding to the joint portion of the brick, it is preferable to use one having a certain width in consideration of construction errors and the like. In particular, the width is preferably 20 mm or more and 200 mm or less. In particular, the thickness is more preferably 40 mm or more and 100 mm or less. The width of the water-cooled tube here means the distance between both ends of the water-cooled tube when viewed in the horizontal direction regardless of the shape. This is because by having such a range, it can be surely installed so as to correspond to the joint portion of the brick, and furthermore, the joint portion of the brick and its periphery can be sufficiently cooled. . In addition, when attaching the heat-transfer material 18 and the water cooling pipe | tube 19 to an apparatus, it is preferable to construct so that these centerlines may correspond with the joint part of a brick. This is because the cooling can be performed equally to the left and right with the joint as the center.

Also, the material of the water-cooled tube is not limited, and is appropriately selected in consideration of heat resistance, corrosion resistance, heat transfer, and the like. However, it is particularly preferable to use a pipe made of metal such as stainless steel, soft iron, aluminum, or copper from the viewpoint of heat transfer performance, corrosion resistance, and the like. Furthermore, it is more preferable to use soft iron or stainless steel in consideration of workability and cost.

The temperature and flow rate of water in the water-cooled pipe are not limited, and can be adjusted as appropriate while monitoring the temperature distribution of the bottom casing. However, during the steady operation of the float glass manufacturing apparatus, the water temperature is preferably controlled to be in the range of 20 to 40 ° C. The temperature does not need to be uniform in the water-cooled tube, and means that the temperature falls within the temperature range as a whole. This is because, when the temperature of the cooling water is in the temperature range, it is possible to cool the bottom casing to an appropriate temperature range without excessively cooling the bottom casing.

By using the float glass manufacturing apparatus having the above configuration, the temperature of the bottom casing can be made uniform, so that generation of gas from the molten tin is suppressed, and glass with less defects due to gas can be manufactured. it can.

Although the cooling mechanism using the water-cooled pipe, which is a feature of the present invention, has been described, in order to further lower the temperature of the entire float bath, in addition to the above cooling mechanism, the entire bottom casing such as an air cooling mechanism similar to the ordinary float method is used. It is preferable to use a means for uniformly cooling the water. Further, the place where the water cooling mechanism of the present invention is provided is not limited to the joint part of the brick, and for example, if there is a part where the temperature is locally high in the bottom casing, the part is installed in the part. It is also possible.

As a method for producing a float glass using the float glass production apparatus of the present invention, a process similar to a normal float method can be employed. Specifically, after a raw material having a target glass composition is charged into a melting tank by a raw material charging machine to melt the raw material, a clarification and defoaming step is performed through a stirring device. Next, it is introduced into a float bath having the structure of the present invention, and after forming into a target plate thickness, for example, 0.1 to 0.7 mm, it is gradually cooled and processed to produce float glass.

In the float glass manufacturing apparatus of the present invention and the manufacturing method using the same, any composition can be applied as long as the glass is manufactured by the float process, but an alkali-free glass containing the following components can be used. It can be used particularly advantageously when manufacturing. Here, each percentage has shown the mass percentage of the oxide basis.
SiO ₂ : 50 to 73%, preferably 50 to 66%
Al ₂ O ₃ : 10.5-24%
B ₂ O ₃ : 0 to 12%
MgO: 0-8%
CaO: 0 to 14.5%
SrO: 0-24%
BaO: 0 to 13.5%
MgO + CaO + SrO + BaO: 8 to 29.5%, preferably 9 to 29.5%
ZrO ₂ : alkali-free glass containing 0 to 5%.

This is because the alkali-free glass has a melting point about 100 ° C. higher than that of the alkali glass, so that a temperature difference is likely to occur in the bottom casing. As a result, gas is likely to be released from the molten tin, which may cause defects on the glass surface. However, since alkali-free glass is often used for display applications, it is particularly undesirable to cause defects on the glass surface. Therefore, by adopting the float glass apparatus of the present invention and the glass manufacturing method using the same, it is possible to manufacture higher quality glass.

In addition to the above-described composition, it can be preferably applied to the production of alkali-free glass containing the following components for the same reason. Again, each percentage represents an oxide-based mass percentage.
SiO ₂ : 58 to 66%
Al ₂ O ₃ : 15-22%
B ₂ O ₃ : 5-12%
MgO: 0-8%
CaO: 0-9%
SrO: 3 to 12.5%
BaO: 0-2%
MgO + CaO + SrO + BaO: alkali-free glass containing 9 to 18%.

Furthermore, the present invention can be preferably applied to alkali-free glass containing the following components. Again, each percentage represents an oxide-based mass percentage.
SiO ₂ : 50 to 61.5%
Al ₂ O ₃ : 10.5-18%
B ₂ O ₃ : 7 to 10%
MgO: 2-5%
CaO: 0 to 14.5%
SrO: 0-24%
BaO: 0 to 13.5%
MgO + CaO + SrO + BaO: alkali-free glass containing 16 to 29.5%.

In particular, when considering a high strain point, preferably, the oxide-based mass percentage display,
SiO ₂ : 56 to 70%
Al ₂ O ₃ : 14.5 to 22.5%
B ₂ O ₃ : 0 to 2%
MgO: 0 to 6.5%
CaO: 0-9%
SrO: 0 to 15.5%
BaO: 0 to 2.5%
MgO + CaO + SrO + BaO: alkali-free glass containing 10 to 26%.

In particular, when considering a high strain point and solubility, preferably, in oxide-based mass percentage display,
SiO ₂ : 54 to 73%
Al ₂ O ₃ : 10.5 to 22.5%
B ₂ O ₃ : 1.5 to 5.5%
MgO: 0 to 6.5%
CaO: 0-9%
SrO: 0 to 16%
BaO: 0 to 2.5%
MgO + CaO + SrO + BaO: Alkali-free glass containing 8 to 25%.

As described above, according to the float glass manufacturing apparatus of the present invention, the temperature difference and temperature distribution in the bottom casing can be reduced or eliminated, and the temperature of the entire bottom casing can be made uniform. And since the temperature of a bottom casing becomes uniform, the gas discharge | release from molten tin can be suppressed. For this reason, if glass is manufactured with the manufacturing method using the manufacturing apparatus which concerns, higher quality glass can be manufactured. Moreover, an advantageous effect can be exhibited particularly when used in the production of alkali-free glass.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific embodiments, and various modifications, It can be changed.

This international application claims priority based on Japanese Patent Application No. 2011-178103 filed on Aug. 16, 2011. The entire contents of Japanese Patent Application No. 2011-178103 are hereby filed here. Incorporated into.

13 Molten tin 15 Bottom brick 16 Bottom casing 18 Heat transfer material 19 Water-cooled tube

Claims

A float glass manufacturing apparatus having a water-cooled pipe for cooling a bottom casing covering a bottom brick bottom of a bathtub where molten tin is prepared,
The water cooling pipe is provided at least along the joint position of the bottom brick via a heat transfer material at the bottom of the bottom casing,
The heat transfer material has a hardness of 10 to 50 (Asker C), a heat transfer coefficient λ / d of 0.2 × 10 3 to 1.6 × 10 3 W / (m 2 · K), The apparatus for producing float glass, wherein the thickness d is 0.001 to 0.05 m.
The float glass manufacturing apparatus according to claim 1, wherein the heat transfer material is made of silicone resin or cement.
The float glass manufacturing apparatus according to claim 1 or 2, wherein the bottom casing is made of soft iron or stainless steel, and the water-cooled tube is made of soft iron or stainless steel.
The float glass manufacturing apparatus according to any one of claims 1 to 3, wherein a width of the water-cooled tube and the heat transfer material is 20 to 200 mm.
The float glass manufacturing apparatus according to any one of claims 1 to 4, wherein the water temperature in the water-cooled tube is 20 to 40 ° C.
A float glass production method, comprising producing float glass using the float glass production apparatus according to any one of claims 1 to 5.
The float glass is an oxide based mass percentage,
SiO 2 : 50 to 73%,
Al 2 O 3 : 10.5-24%,
B 2 O 3 : 0 to 12%,
MgO: 0-8%,
CaO: 0 to 14.5%,
SrO: 0 to 24%,
BaO: 0 to 13.5%,
The total of MgO, CaO, SrO, BaO is 8-29.5%,
ZrO 2 : 0 to 5%
The float glass production method according to claim 6, wherein the glass is a non-alkali glass containing as a component thereof.