TW201433548A - Molding device for float glass and method for manufacturing float glass - Google Patents

Abstract

Provided is a molding device for float glass that is provided with a molten tin tank which holds molten tin, and that forms band-shaped glass ribbons by causing molten glass to flow on the molten tin in the molten tin tank, wherein the molding device is further provided with the following: a projecting wall that projects from the top of the side bricks of the molten tin tank and that forms a gap with respect to an exposed portion of the molten tin which is in the molten tin tank and is not covered by the glass ribbon and an air feed pipe that feeds a reducing gas into the gap via through holes in the projecting wall.

Description

Forming device for floating glass and method for manufacturing floating glass Field of invention

The present invention relates to a forming apparatus for floating glass and a method of manufacturing floating glass.

Background of the invention

The floating glass forming apparatus includes a molten tin bath for containing molten tin, and the molten glass flows on the molten tin in the molten tin bath to form a strip-shaped glass ribbon. The glass ribbon was pulled from the molten tin in the downstream region of the molten tin bath and then cold-cut. In this way, a glass plate can be obtained.

The floating glass forming apparatus further includes a top wall disposed above the molten tin bath (for example, refer to the patent literature). A gas supply path for supplying a reducing gas to a space between the top wall and the molten tin bath (the upper space of the forming apparatus) is formed in the top wall. The reducing gas reacts with oxygen which is mixed from the outside into the upper space of the forming apparatus to suppress oxidation of the molten tin in the molten tin bath. The reducing gas generally uses a mixed gas containing nitrogen and hydrogen.

Advanced technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2006-16291

Summary of invention

However, a portion of the oxygen mixed into the upper space of the forming device from the outside is dissolved in the molten tin. Therefore, the molten tin contains oxygen as an impurity, and the tin oxide vapor is volatilized from the exposed portion of the molten tin. When the volatilized tin oxide vapor is cooled, it is formed as tin oxide particles. There is a case where the tin oxide particles fall onto the glass ribbon to cause defects.

The present invention has been made in view of the above problems, and an object of the invention is to provide a molding apparatus for a floating glass which can obtain a glass plate of good quality.

In order to solve the above problems, an aspect of the present invention is a molding apparatus for a floating glass including a molten tin bath containing molten tin and flowing molten glass on the molten tin in the molten tin bath to form a strip-shaped glass ribbon. The floating glass forming device further includes a protruding wall and an air supply pipe protruding from an upper portion of the side brick of the molten tin bath and not covered by the glass ribbon in the molten tin in the molten tin bath. A gap is formed between the exposed portions; the gas supply pipe supplies a reducing gas to the gap through the through hole of the protruding wall.

According to the present invention, it is possible to provide a forming apparatus for a floating glass in which a glass plate of good quality can be obtained.

10‧‧‧glass materials

12‧‧‧ molten glass

14‧‧‧glass ribbon

100‧‧‧Floating glass manufacturing equipment

200‧‧‧melting device

210‧‧‧melting tank

220‧‧‧ burner

300,1300,2300,3300‧‧‧forming device

302‧‧‧ top wall

304‧‧‧Upper space

306‧‧‧ gap

310‧‧‧Fused tin

311‧‧‧ exposed part

312‧‧‧ covered parts

314‧‧‧ tin oxide particles

320‧‧‧Fused tin bath

322‧‧‧shell

324‧‧‧Bottom brick

326‧‧‧ side brick

330‧‧‧ gas supply path

332‧‧‧heater

340,340A, 347‧‧ ‧ protruding wall

341-346‧‧‧Block

348‧‧‧ prominent wall body

349‧‧‧Antioxidant film

350‧‧‧ gas supply pipe

352‧‧‧Exhaust pipe

360‧‧‧Lead straight wall

400‧‧‧Xu cold installation

410‧‧‧Xu cold furnace

420‧‧‧Transport roller

440‧‧‧heater

510‧‧‧lifting roller

F‧‧‧ distance

G‧‧‧ interval

H‧‧‧ interval

H‧‧‧ interval

L1‧‧‧X-direction dimensions of the protruding wall 340

L2‧‧‧X-direction dimension of molten tin 310 in molten tin bath 320

V‧‧‧Y household size

W‧‧‧ interval

X, Y‧‧ direction

Z1‧‧ wide area

Z2‧‧‧ intermediate area

Z3‧‧‧ narrow area

1 is a view showing the manufacture of a floating glass according to an embodiment of the present invention. A cross-sectional view of the device.

Fig. 2 is a cross-sectional view showing a molding apparatus for a floating glass according to an embodiment of the present invention.

Fig. 3 is a plan view showing the structure of a lower portion of a forming apparatus for a floating glass according to an embodiment of the present invention.

Figure 4 is a cross-sectional view taken along line IV-IV of Figure 3.

Fig. 5 is a cross-sectional view showing a structure of a lower portion of a molding apparatus for a floating glass according to a first modification.

Fig. 6 is a plan view showing a structure of a lower portion of a molding apparatus for a floating glass according to a second modification.

Fig. 7 is a cross-sectional view showing a structure of a lower portion of a molding apparatus for a floating glass according to a third modification.

Fig. 8 is a plan view showing a structure of a lower portion of a forming apparatus for a floating glass according to a fourth modification.

Fig. 9 is a plan view showing a structure of a lower portion of a molding apparatus for a floating glass according to a fifth modification.

Fig. 10 is a plan view showing a structure of a lower portion of a molding apparatus for a floating glass according to a sixth modification.

Form for implementing the invention

Hereinafter, the form for carrying out the invention will be described with reference to the drawings. In the following drawings, the same or corresponding components are designated by the same or corresponding numerals, and the description is omitted. In each of the drawings, the X direction indicates the flow direction of the glass ribbon, and the Y direction indicates the width direction of the glass ribbon. X direction and Y The directions are the directions perpendicular to each other.

Fig. 1 is a cross-sectional view showing a manufacturing apparatus for a floating glass according to an embodiment of the present invention. As shown in Fig. 1, the floating glass manufacturing apparatus 100 includes a melting glass material 10 as a melting device 200 of the molten glass 12, and the molten glass 12 supplied from the melting apparatus 200 is formed into a strip shape as a glass. The forming device 300 of the belt 14 and the undercooling device 400 which is cooled by the glass ribbon 14 formed by the forming device 300.

The melting apparatus 200 has a melting tank 210 that accommodates the molten glass 12, and a burner 220 that forms a flame above the molten glass 12 accommodated in the melting tank 210. The glass raw material 10 put into the melting tank 210 is gradually melted into the molten glass 12 by the radiant heat of the flame formed by the burner 220. The molten glass 12 can be continuously supplied from the melting tank 210 to the forming apparatus 300.

The molding apparatus 300 has a molten tin bath 320 that accommodates molten tin 310. The molten glass 12 can be continuously supplied onto the molten tin 310 in the molten tin bath 320. The molding apparatus 300 causes the molten glass 12 to flow on the molten tin 310 in the molten tin bath 320 to form a ribbon-shaped glass ribbon 14. The glass ribbon 14 flows in a predetermined direction while gradually cooling, and gradually solidifies. The glass ribbon 14 is pulled up from the molten tin 310 in the downstream region of the molten tin bath 320, and is carried to the quenching device 400 by the lift roller 510.

The chilling device 400 cools the glass ribbon 14 formed by the forming device 300. The quenching device 400 has, for example, a quenching furnace (lehr) 410 having a heat insulating structure, and a plurality of conveying rollers 420 disposed in the quenching furnace 410 to convey the glass ribbon 14 in a predetermined direction. The gas ambient temperature in the cold furnace 410 is from the inlet to the outlet of the cold furnace 410, and is getting colder and lower. Gas in the cold furnace 410 The ambient temperature can be adjusted by the heater 440 or the like provided in the cold furnace 410. The glass ribbon 14 taken out from the outlet of the cold furnace 410 is cut into a predetermined size by a cutter to obtain a glass plate as a product.

Fig. 2 is a cross-sectional view showing a molding apparatus for a floating glass according to an embodiment of the present invention. Fig. 3 is a plan view showing the structure of a lower portion of a forming apparatus for a floating glass according to an embodiment of the present invention. Figure 4 is a cross-sectional view taken along line IV-IV of Figure 3.

As shown in FIG. 2, the molding apparatus 300 is comprised by the molten tin tank 320 which accommodates the molten tin 310, the top wall 302 arrange|positioned above the molten tin tank 320, etc.. The top wall 302 is provided with a gas supply path 330 for supplying a reducing gas to a space (the upper space of the forming device 300) 304 between the top wall 302 and the molten tin bath 320. Further, a heater 332 as a heating source is inserted into the gas supply path 330.

In order to suppress oxidation of the molten tin 310, the gas supply path 330 supplies the reducing gas to the upper space 304 of the forming apparatus 300. The reducing gas contains, for example, 1 to 15% by volume of hydrogen and 85 to 99% by volume of nitrogen. To limit the incorporation of outside air, the upper space 304 of the forming apparatus 300 is formed to be higher than atmospheric pressure.

In order to adjust the temperature distribution of the glass ribbon 14, the heater 332 is provided in plural, for example, in the flow direction (X direction) and the width direction (Y direction) of the glass ribbon 14. The output of the heater 332 is controlled to be downstream from the upstream side, and the temperature of the glass ribbon 14 is lower. Further, the output of the heater 332 is controlled such that the thickness of the glass ribbon 14 is uniform in the width direction.

The molten tin bath 320 has a metal casing 322 that is open at the top, and a bottom brick 324 and side bricks 326 that are disposed in the casing 322. The housing 322 is used Prevent the intrusion of outside air. The lower surface of the casing 322 is exposed to the external space to be naturally cooled. The bottom brick 324 protects the inside bottom surface of the housing 322, and the side bricks 326 protect the inside side of the housing 322. A plurality of bottom bricks 324 are arranged in a two-dimensional manner in the X direction and the Y direction. The plurality of side bricks 326 are arranged in a quadrangular ring shape along the inner side surface of the casing 322 in a state of surrounding the plurality of bottom bricks 324.

As shown in FIG. 3, the upper surface of the molten tin 310 in the molten tin bath 320 has a wide region Z1 having a large width from the upstream side, an intermediate portion Z2 having a narrow width, and a narrow region Z3 having a narrow width. In the case of an alkali-containing glass, the temperature of the wide region Z1 is set to 700 ° C or higher. Further, in the case of an alkali-free glass, the temperature of the wide region Z1 is set to 900 ° C or higher.

As shown in FIG. 4, the molten tin 310 in the molten tin bath 320 has an exposed portion 311 not covered by the glass ribbon 14 and a covered portion 312 covered by the glass ribbon 14. As shown in FIG. 3, the exposed portions 311 are located on both sides in the width direction of the glass ribbon 14.

As shown in FIG. 4, the forming apparatus 300 further includes a protruding wall 340 which protrudes from an upper portion of the side brick 326 of the molten tin bath 320 and forms a gap 306 between the exposed portion 311 of the molten tin 310 in the molten tin bath 320. . The protruding wall 340 is, for example, a plate shape and is horizontally disposed above the molten tin 310. The protruding wall 340 restricts the contact of the oxygen mixed with the molten tin 310 from the outside into the space above the protruding portion 340, and suppresses the increase in the oxygen concentration in the molten tin 310. Further, the protruding wall 340 receives the tin oxide particles 314 dropped from above, and prevents the tin oxide particles 314 from falling to the molten tin 310.

Further, the protruding wall 340 of the present embodiment is set to a level with respect to the liquid surface of the molten tin 310. For example, the liquid surface of the molten tin 310 may be inclined. oblique.

Further, the molding apparatus 300 further includes an air supply pipe 350 that supplies a reducing gas to the gap 306 between the protruding wall 340 and the exposed portion 311 of the molten tin 310 via the through hole of the protruding wall 340. The reducing gas of the gas supply pipe 350 contains, for example, hydrogen (H ₂ ). The reducing gas of the gas supply pipe 350 may be a mixed gas containing an inert gas such as nitrogen (N ₂ ), and may be a gas of the same kind as the reducing gas of the gas supply path 330 in order to reduce the cost. The reducing gas of the gas supply pipe 350 may be a high temperature gas without cooling the molten tin 310 or the glass ribbon 14, and the annular gas heater may be wound around the gas supply pipe 350.

The gas supply pipe 350 can adjust the composition of the gaseous environment in contact with the exposed portion 311 of the molten tin 310 to the desired period by supplying a reducing gas to the gap 306 between the protruding wall 340 and the exposed portion 311 of the molten tin 310. composition. Therefore, as will be described later in detail, the volatilization of the tin oxide vapor (SnO) evaporated from the exposed portion 311 of the molten tin 310 can be restricted, and the oxygen concentration in the molten tin 310 can be reduced.

The reducing gas (for example, H ₂ ) supplied from the gas supply pipe 350 to the gap 306 reacts with the tin oxide vapor (SnO) evaporated from the exposed portion 311 of the molten tin 310 to form tin vapor (Sn) and water vapor (H ₂ O). ). When the amount of tin vapor in the gap 306 exceeds the saturated vapor amount, the newly formed tin vapor is formed as tin droplets and falls onto the molten tin 310. On the other hand, the water vapor is discharged to the outside of the forming apparatus 300 through the upper space 304 of the forming apparatus 300 together with the unreacted reducing gas.

Thus, the reducing gas (for example, H ₂ ) supplied from the gas supply pipe 350 to the gap 306 decomposes the tin oxide vapor (SnO) evaporated from the exposed portion 311 of the molten tin 310, thereby suppressing the volatilization of the tin oxide vapor. Therefore, it is possible to suppress the tin oxide particles which can be generated from the tin oxide vapor from falling onto the glass ribbon 14. The volatilization of the tin oxide vapor (SnO) from the molten tin 310 is likely to occur at 700 ° C or higher, and is remarkable at 800 ° C or higher, and is particularly remarkable at 1000 ° C or higher.

Further, a reducing gas (for example, H ₂ ) supplied from the gas supply pipe 350 to the gap 306 is brought into contact with the exposed portion 311 of the molten tin 310, and reacts with oxygen in the molten tin 310 to generate water vapor. This water vapor and unreacted reducing gas are discharged to the outside of the forming apparatus 300 through the upper space 304 of the forming apparatus 300.

Thus, the reducing gas (for example, H ₂ ) supplied from the gas supply pipe 350 to the gap 306 can reduce the oxygen concentration in the molten tin 310. Therefore, the amount of the tin oxide vapor evaporated from the exposed portion 311 of the molten tin 310 can be reduced.

The hydrogen concentration (% by volume) in the reducing gas supplied from the gas supply pipe 350 to the gap 306 is preferably higher than the hydrogen concentration (% by volume) in the reducing gas supplied from the gas supply path 330 to the upper space 304 of the forming apparatus 300. When the gas supply pipe 350 is not provided, the reducing power of the gas atmosphere in contact with the exposed portion 311 of the molten tin 310 is increased. The reducing gas supplied from the gas supply pipe 350 to the gap 306 may be substantially composed only of hydrogen gas, and may have a hydrogen gas concentration of 99% by volume or more.

Further, the reducing gas of the air supply pipe 350 of the present embodiment contains hydrogen gas as a gas having a reducing power, and the gas having a reducing power is not limited to hydrogen gas. For example, the reducing gas of the gas supply pipe 350 may also contain acetylene gas (C ₂ H ₂ ) as a gas having a reducing power. The acetylene gas has a reducing power higher than that of hydrogen. At this time, the concentration of acetylene gas (% by volume) in the reducing gas supplied from the gas supply pipe 350 to the gap 306 may be lower than the concentration of hydrogen gas supplied from the gas supply path 330 to the reducing gas in the upper space 304 of the forming apparatus 300. (volume%). As compared with the case where the gas supply pipe 350 is not provided, the reducing power of the gas atmosphere in contact with the exposed portion 311 of the molten tin 310 may be high.

The protruding wall 340 is formed of carbon (C) and is exposed to a reducing gas supplied from the air supply pipe 350 to the gap 306. Carbon has a reducing power and generates carbon monoxide gas (CO) in an environment with a low oxygen concentration. The carbon reacts with tin oxide vapor (SnO) evaporated from the exposed portion 311 of the molten tin 310 to form tin vapor (Sn) and carbon monoxide gas (CO). When the amount of tin vapor in the gap 306 exceeds the saturated vapor amount, the newly formed tin vapor is formed as tin droplets and falls onto the molten tin 310 in the molten tin bath 320. On the other hand, the carbon monoxide gas is discharged to the outside of the forming apparatus 300 through the upper space 304 of the forming apparatus 300 together with the unreacted reducing gas.

Thus, the protruding wall 340 formed of carbon decomposes the tin oxide vapor (SnO) evaporated from the exposed portion 311 of the molten tin 310, thereby suppressing the volatilization of the tin oxide vapor. Therefore, it is possible to suppress the tin oxide particles which can be generated from the tin oxide vapor from falling onto the glass ribbon 14. The carbon reduction reaction is easily carried out at 450 ° C or higher.

Further, since the wettability of the protruding wall 340 formed of carbon and the molten glass is good, the flow of the glass ribbon 14 is unstable, and when the glass ribbon 14 comes into contact with the protruding wall 340, the fluidity of the glass ribbon 14 is not easily hindered.

As shown in FIG. 3, the protruding wall 340 can be divided into a plurality of blocks 341 to 346 which are continuously arranged in the flow direction (X direction) of the glass ribbon 14. Since each of the blocks 341 to 346 can be set, the setting work is easy.

The protruding wall 340 can be disposed in a wide area Z1 of high temperature. Due to wide area Since the temperature of Z1 is 700 ° C or more at the start of the volatilization of the general tin oxide vapor (SnO), the reaction of generating an oxygen-containing gas (for example, water vapor or carbon monoxide gas) and tin droplets from the tin oxide vapor is progressing rapidly.

The X-direction dimension L1 of the protruding wall 340 may be 10% or more, preferably 30% or more, more preferably 50% or more, more preferably L2, of the X-direction dimension L2 of the molten tin 310 in the molten tin bath 320. More than 70%, especially better than 90% of L2.

The protruding wall 340 may be provided at a position that does not overlap the glass ribbon 14 when viewed from above. The operator can confirm the position of the side end of the glass ribbon 14. In order to sufficiently obtain the effect of reducing gas supplied to the gap 306, the interval W (refer to FIG. 4) in the width direction (Y direction) of the glass ribbon between the front end of the protruding wall 340 and the side end of the glass ribbon 14 is, for example, 150 mm. Hereinafter, it is preferably 100 mm or less, more preferably 50 mm or less, and particularly preferably 25 mm or less. Further, in order to confirm the position of the side end of the glass ribbon 14, the interval W is larger than, for example, 0 mm, preferably 10 mm or more, and more preferably 15 mm or more.

Further, as shown in FIG. 8, the portion where the position of the side end of the glass ribbon 14 is not required to be confirmed may be overlapped with the protruding wall 340A when viewed from above. That is, when the front end portion of the protruding wall 340A is viewed from above, it may have both a portion overlapping the glass ribbon 14 and a portion not overlapping the glass ribbon 14, and may have a concavo-convex shape. In this case, in order to prevent the glass ribbon 14 from being exposed to the reducing gas having a large reducing power supplied from the gas supply pipe 350, the Y-direction dimension V of the region where the protruding wall 340A overlaps the glass ribbon 14 is 150 mm or less when viewed from above. It is 100 mm or less, more preferably 50 mm or less, and particularly preferably 25 mm or less (Fig. 8).

In order to suppress the increase in the number of ventilations described later, the underside of the protruding wall 340 The interval H (see FIG. 4) between the exposed portion 311 of the molten tin 310 is, for example, 100 mm or less, preferably 50 mm or less, more preferably 25 mm or less, still more preferably 10 mm or less. Further, since the balance plate thickness of the molten glass in the natural state without external force is about 7 mm, the gap H is prevented from coming into contact with the glass ribbon 14, and the interval H is, for example, more than 7 mm.

When the number of air changes per hour of the gap 306 between the protruding wall 340 and the molten tin 310 is too small, the purification treatment cannot be sufficiently performed. When the amount is too large, the cost is increased, so it is preferably 3 to 20 times, more preferably 8~10 times. Here, the number of air exchanges can be calculated by the ratio of the volume (Nm ³ ) of the standard state (1 atmosphere, 25 ° C) of the reducing gas supplied to the gap 306 to the volume of the gap 306 between 1 hour.

Fig. 5 is a cross-sectional view showing a structure of a lower portion of a molding apparatus for a floating glass according to a first modification, which corresponds to Fig. 4 . The forming apparatus 1300 shown in FIG. 5 differs from the forming apparatus 300 shown in FIG. 4 in that it further includes a vertical wall 360 that protrudes from the lower surface of the protruding wall 340. In the following, the main points are different.

The vertical wall 360 protrudes from the underside of the protruding wall 340. The vertical wall 360 may be integrally formed with the protruding wall 340. As shown in FIG. 5, the vertical wall 360 may extend from the front end to the lower end of the protruding wall 340, or may extend from the front end to the base end of the protruding wall 340 to the lower side. A vertical wall 360 is formed along the side edge of the glass ribbon 14 from the upstream end to the downstream end of the protruding wall 340.

Further, in the present embodiment, the vertical straight wall 360 which is perpendicular to the liquid surface of the molten tin 310 is provided as a wall which protrudes from the lower surface of the protruding wall 340. For example, a wall which is inclined with respect to the liquid surface of the molten tin 310 may be provided.

The through hole connecting the protruding wall 340 of the front end portion of the air supply pipe 350 is located between the side brick 326 of the supporting protruding wall 340 and the vertical wall 360. Therefore, the reducing gas supplied from the air supply pipe 350 to the gap 306 is integrated throughout the gap 306 along the vertical wall 360.

The vertical wall 360 may be provided at a position that does not overlap the glass ribbon 14 when viewed from above. In order to sufficiently obtain the effect of reducing gas supplied to the gap 306, the distance G between the vertical wall 360 and the side end of the glass ribbon 14 in the width direction (Y direction) of the glass ribbon is, for example, 150 mm or less, preferably 100 mm or less. More preferably, it is 50 mm or less, and particularly preferably 25 mm or less. Further, in order to confirm the position of the side end of the glass ribbon 14, the interval G is, for example, more than 0 mm, preferably 10 mm or more, and more preferably 15 mm or more.

The vertical wall 360 is disposed above the molten tin 310 and the glass ribbon 14 without impeding the flow of the molten tin 310 and the glass ribbon 14. In order to facilitate the passage of the reducing gas supplied from the air supply pipe 350 to the gap 306 throughout the gap 306, the interval h between the lower end of the vertical wall 360 and the exposed portion 311 of the molten tin 310 is preferably 50 mm or less, more preferably 25 mm or less. More preferably, it is 10 mm or less. Further, since the balance plate thickness of the molten glass in the natural state without external force is about 7 mm, in order to prevent the vertical wall 360 from coming into contact with the glass ribbon 14, the interval h is preferably larger than, for example, 7 mm.

Further, as shown in FIG. 9, the vertical wall 360 may also protrude from the lower surface of the protruding wall 340A overlapping the glass ribbon 14 when viewed from above. Since the vertical wall 360 is more easily contacted with the glass ribbon 14 than the protruding wall 340A, unlike the protruding wall 340A, it can be disposed at a position that does not overlap the glass ribbon 14 when viewed from above. It is also possible to suppress the glass ribbon 14 from being exposed to the reducing gas having a large reducing power supplied from the gas supply pipe 350. Glass strip between the vertical wall 360 and the side end of the glass ribbon 14 The interval G in the width direction (Y direction) may be the above range.

However, as shown in FIG. 10, the vertical wall 360A may have a portion overlapping the glass ribbon 14 when viewed from above, similarly to the protruding wall 340A. This portion protrudes from the side end of the glass ribbon 14 toward the inner side in the width direction of the glass ribbon 14. In order to suppress the glass ribbon 14 from being exposed to the reducing gas having a large reducing power supplied from the gas supply pipe 350, the distance F is 150 mm or less, preferably 100 mm or less, more preferably 50 mm or less, and particularly preferably 25 mm or less.

Fig. 6 is a plan view showing a structure of a lower portion of a molding apparatus for a floating glass according to a second modification, which corresponds to Fig. 3; The forming device 2300 shown in FIG. 6 differs from the forming device 300 shown in FIG. 3 in that it further includes an exhaust pipe 352 that discharges the protruding wall 340 and the molten tin 310 via the through hole of the protruding wall 340. The gas in the gap 306 between the portions 311 is exposed. In the following, the main points are different.

The exhaust pipe 352 guides the reducing gas supplied from the air supply pipe 350 to the gap 306 to the exhaust pipe 352. Therefore, the reducing gas tends to spread over the entire gap 306. An intake source may be provided at a base end portion of the exhaust pipe 352. Further, the exhaust pipe 352 suppresses the glass ribbon 14 from being exposed to the reducing gas having a large reducing power supplied from the air supply pipe 350. Further, the positions of the air supply pipe 350 and the exhaust pipe 352 are not limited to those shown in FIG. 6. For example, in FIG. 6, the positions of the air supply pipe 350 and the exhaust pipe 352 may be reversed. Further, a plurality of supply pipes 350 and exhaust pipes 352 may be separately provided.

Further, a vertical wall 360 may be provided on the lower surface of the protruding wall 340 to which the exhaust pipe 352 is connected, similarly to the first modification. At this time, the through hole of the protruding wall 340 connecting the front end portion of the exhaust pipe 352 is located between the side brick 326 of the supporting protruding wall 340 and the vertical wall 360.

Fig. 7 is a cross-sectional view showing a structure of a lower portion of a molding apparatus for a floating glass according to a third modification, which corresponds to Fig. 4; The forming device 3300 shown in FIG. 7 differs from the forming device 300 shown in FIG. 4 in that it includes a protruding wall 347 having a protruding wall body 348 formed of carbon and an oxidation resistant film 349 for protecting the protruding wall body 348. . In the following, the main points are different.

The protruding wall body 348 is formed of carbon. In order to suppress the burning of carbon, an anti-oxidation film 349 is provided on the protruding wall body 348.

The oxidation resistant film 349 is formed of a ceramic such as tantalum carbide (SiC). The method of forming the oxidation resistant film 349 is, for example, a thermal spraying method or the like. The oxidation resistant film 349 may cover the entire surface of the protruding wall 340.

Further, when the vertical wall 360 is protruded from the lower surface of the protruding wall 340, the vertical wall 360 may be formed of a vertical straight wall body formed of carbon and an oxidation resistant film for protecting the vertical wall body. At this time, the protruding wall body and the vertical wall body may be integrally formed.

In the above, the embodiment of the apparatus for forming a floating glass is described. The present invention is not limited to the above-described embodiments and the like, and various modifications and improvements can be made within the scope of the claims.

For example, the protruding wall 340 of the above embodiment may be formed of carbon or ceramic, and the material of the protruding wall 340 may be a material having heat resistance.

The present application claims the priority of Japanese Patent Application No. 2012-256510, the entire disclosure of which is incorporated herein by reference.

14‧‧‧glass ribbon

300‧‧‧Forming device

302‧‧‧ top wall

304‧‧‧Upper space

306‧‧‧ gap

310‧‧‧Fused tin

311‧‧‧ exposed part

312‧‧‧ covered parts

314‧‧‧ tin oxide particles

324‧‧‧Bottom brick

326‧‧‧ side brick

330‧‧‧ gas supply path

332‧‧‧heater

340‧‧‧ protruding wall

350‧‧‧ gas supply pipe

H‧‧‧ interval

W‧‧‧ interval

Y‧‧‧ direction

Claims (6)

A floating glass forming apparatus includes a molten tin bath for containing molten tin, and molten glass flows on the molten tin in the molten tin bath to form a strip-shaped glass ribbon, and the floating glass forming apparatus further includes a protruding wall protruding from an upper portion of the side brick of the molten tin bath and forming a gap between the exposed portion of the molten tin in the molten tin bath not covered by the glass ribbon; and an air supply tube A through hole of the protruding wall is provided to supply a reducing gas to the aforementioned gap. The forming apparatus of the floating glass of claim 1, further comprising: a top wall disposed above the molten tin bath; and a gas supply path formed on the top wall to supply a reducing gas to the top wall a space between the molten tin bath and the reducing gas supplied from the gas supply pipe to the gap is higher than a hydrogen concentration in the reducing gas supplied from the gas supply path to the space. A forming device for a floating glass according to claim 1 or 2, further comprising a wall protruding from a lower surface of the protruding wall; a through hole connecting the protruding wall of the front end portion of the air supply pipe is located at a side brick and a side supporting the protruding wall The underside of the protruding wall protrudes between the walls. The forming apparatus for a floating glass according to any one of claims 1 to 3, wherein the protruding wall is formed of carbon and exposed to the gap from the gas supply pipe to the gap In the reducing gas. The forming apparatus for a floating glass according to any one of claims 1 to 3, wherein the protruding wall has a protruding wall body formed of carbon, and an oxidation resistant film protecting the protruding wall body. A method for producing a floating glass, which is a glass sheet formed by using a forming apparatus for a floating glass according to any one of claims 1 to 5.