TW201507982A - Float glass production device and float glass production method using same - Google Patents

Abstract

A float glass production device provided with: a bath containing a molten metal; a ceiling situated above the bath and extending from an entrance wall to an exit wall; a plurality of top rolls provided so as to be spaced along the flow direction of a glass ribbon flowing above the liquid level of the molten metal, rotating by themselves and pressing the widthwise extremities of the glass ribbon having traversed the space between the liquid level and the entrance wall; a dividing wall whereby a forming space enclosed by the ceiling, the bath, the entrance wall, and the exit wall is divided into a high-temperature space on the upstream side and a low-temperature space on the downstream side; and an exhaust path wherefrom a gas in the high-temperature space is exhausted to the exterior of the forming space. The dividing wall is arranged more to the downstream side than the entrance wall and upstream from the top roll on the most upstream-side among the plurality of top rolls.

Description

Floating glass manufacturing device and floating glass manufacturing method using same

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

The method for producing a float glass includes a forming step of forming a sheet shape even if a glass ribbon flows on a liquid surface of a molten metal (for example, molten tin) in a bath (for example, refer to Patent Document 1). The forming space between the bath and the top wall may be filled with a reducing gas to suppress oxidation of the molten metal. The forming space contains a small amount of gas evaporated by the molten metal. The gas contains a metal element evaporated from the molten metal in the form of at least one of a monomer and a compound. The compound may, for example, be a metal oxide or a metal sulfide.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 50-3414

Previously, there was a problem that foreign matter such as droplets or particles were formed by cooling of a molten metal vapor, and the foreign matter fell to the upper surface of the glass ribbon, resulting in more defects.

The present invention has been made in view of the above problems, and a main object thereof is to provide a floating glass manufacturing apparatus which reduces the number of defects.

In order to solve the above problems, according to an aspect of the present invention, a floating glass manufacturing is provided. The device comprises: a bath for containing molten metal; an inlet wall above the upstream portion of the bath; an outlet wall above the downstream portion of the bath; and a top wall disposed above the bath and Extending from the inlet wall to the outlet wall; a plurality of upper rolls disposed at intervals along a flow direction of the glass ribbon flowing on the liquid surface of the molten metal, and pressed through the liquid surface and the inlet wall a width direction end portion of the glass ribbon and rotating itself; the partition wall partitioning the forming space surrounded by the top wall, the bath, the inlet wall and the outlet wall into a high temperature space on the upstream side and a low temperature on the downstream side a space; and an exhaust passage that discharges the gas in the high temperature space to the outside of the forming space; and the partition wall is disposed on a downstream side of the inlet wall, and is disposed in the uppermost one of the plurality of upper rolls The upper roller on the upstream side is further upstream.

According to one aspect of the present invention, a floating glass manufacturing apparatus that reduces the number of defects is provided.

10‧‧‧Forming device

11‧‧‧ molten metal

12‧‧‧ molten glass

14‧‧‧glass ribbon

20‧‧‧ bath

22‧‧‧ chute

23‧‧‧Flow channel control gate

24‧‧‧Limited bricks

25‧‧‧Limited bricks

26‧‧‧ entrance wall

27‧‧‧ chute space

28‧‧‧Exit wall

30‧‧‧ top wall

31‧‧‧Top wall housing

32‧‧‧ upper side wall

33‧‧‧ upper side wall

34‧‧‧ gas supply path

36‧‧‧heater

40‧‧‧Upper roll

42‧‧‧ partition wall

44‧‧‧Exhaust passage

46‧‧‧ Connecting rod

47‧‧‧ Nuts

50‧‧‧Forming space

51‧‧‧High temperature space

52‧‧‧low temperature space

53‧‧‧Preheating space

H1‧‧‧ Height

H2‧‧‧ Height

L1‧‧‧ distance

L2‧‧‧ distance

X‧‧‧ direction

Y‧‧‧ direction

Z‧‧‧ range

Fig. 1 is a cross-sectional view showing a molding apparatus for a floating glass manufacturing apparatus according to an embodiment of the present invention.

Figure 2 is a cross-sectional view taken along line II-II of Figure 1.

Figure 3 is a cross-sectional view taken along line III-III of Figure 1.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same or corresponding components are attached to the same or corresponding elements, and the description is omitted. Bright. In the present specification, the "width direction" means a direction orthogonal to the flow direction of the glass ribbon in the forming step.

Fig. 1 is a cross-sectional view showing a molding apparatus for a floating glass manufacturing apparatus according to an embodiment of the present invention. Figure 2 is a cross-sectional view taken along line II-II of Figure 1. In Fig. 2, the heater and the upper side wall are omitted for convenience of viewing the drawings. Figure 3 is a cross-sectional view taken along line III-III of Figure 1.

The float glass manufacturing apparatus includes a forming apparatus 10. In the molding apparatus 10, the glass ribbon 14 is caused to flow on the liquid surface of the molten metal 11 in the bath 20 to be formed into a plate shape. The glass ribbon 14 is pulled from the molten metal 11 in the downstream region of the bath 20 and sent to the slow cooling furnace from the outlet formed between the bath 20 and the outlet wall 28. A plate-shaped floating glass can be obtained by cutting the slow-cooled glass ribbon 14 in the slow cooling furnace.

The forming apparatus 10 includes, as shown, for example, in FIGS. 1 to 3, a bath 20, a spout lip 22, a flow control gate (tweel) 23, restrictor tiles 24, 25, and an inlet wall 26. The outlet wall 28, the top wall 30, the upper side walls 32, 33, the air supply passage 34, the heater 36, the upper roller 40, the partition wall 42, and the exhaust passage 44, and the like.

The bath 20 accommodates the molten metal 11 as shown in Figs. As the molten metal 11, for example, molten tin or a molten tin alloy can be used as long as the glass ribbon 14 can be floated.

The chute 22 is continuously supplied with the molten glass 12 to the liquid surface of the molten metal 11 as shown in FIG. The molten glass 12 is supplied to the liquid surface of the molten metal 11 between the chute port 22 and the flow path control shutter 23 to become the glass ribbon 14.

In order to change the flow rate of the molten glass 12, the flow path control shutter 23 is freely movable in the vertical direction with respect to the chute port 22. The greater the separation between the chute 22 and the flow control shutter 23, the greater the flow rate of the molten glass 12.

The restricting bricks 24, 25 are in contact with the glass ribbon 14 as shown in Fig. 2 to limit the width of the glass ribbon 14. The restricting bricks 24, 25 are extended downstream. Therefore, between the flow restricting bricks 24, 25, the glass ribbon 14 is flowed downstream to expand the width. On the downstream side of the more limited flow bricks 24, 25, The glass ribbon 14 is spaced apart from the side walls of the bath 20 to freely change the width between the side walls of the bath 20.

The inlet wall 26 is located above the upstream portion of the bath 20 as shown in FIG. For example, the inlet wall 26 is disposed on the downstream side of the inclined slot 22 and is disposed above the restricting bricks 24, 25. As shown in FIG. 2, on the upstream side of the inlet wall 26, all of the liquid surface of the molten metal 11 is covered by the glass ribbon 14. On the other hand, on the downstream side of the inlet wall 26, most of the liquid surface of the molten metal 11 is covered by the glass ribbon 14, but a part of the liquid surface of the molten metal 11 is not covered by the glass ribbon 14.

The outlet wall 28 is located above the downstream portion of the bath 20 as shown in FIG.

The top wall 30 is disposed above the bath 20 as shown in FIG. 1 and extends from the inlet wall 26 to the outlet wall 28. The forming space 50 surrounded by the bath 20, the top wall 30, the inlet wall 26, and the outlet wall 28 can be filled with a reducing gas to suppress oxidation of the exposed portion of the liquid surface of the molten metal 11 which is not covered by the glass ribbon 14. In order to reduce the incorporation of external gases, the gas pressure in the forming space 50 may also be higher than atmospheric pressure.

The upper side walls 32, 33 block the gap between the side wall of the bathtub 20 and the top wall 30 as shown in Fig. 3, and suppress the incorporation of external air. The upper side walls 32, 33 extend from the inlet wall 26 to the outlet wall 28. The upper side walls 32 and 33 are formed with a through hole through which the rotating shaft of the upper roller 40 is inserted, an end portion of the exhaust passage 44, and the like.

The heater 36 is inserted into the air supply passage 34 of the top wall 30 as shown in FIG. 1, and the heat generating portion of the heater 36 is disposed in the forming space 50. The heater 36 heats the molten metal 11 and the glass ribbon 14 from above. The heater 36 is provided in plural in the flow direction (X direction) and the width direction (Y direction) of the glass ribbon 14 at intervals. The downstream of the downstream side, the lower the temperature of the glass ribbon 14 is, the more the output of the heater 36 is controlled.

The upper roller 40 is used in pairs as shown in Fig. 2, and presses the end portion in the width direction of the glass ribbon 14, and applies tension to the width direction of the glass ribbon 14. The plurality of upper rollers 40 are disposed at intervals along the flow direction of the glass ribbon 14.

The upper roller 40 has a rotating member that is in contact with the glass ribbon 14 at the front end portion. While the rotating member is rotated to apply tension to the glass ribbon 14 by the plurality of upper rollers 40, the glass ribbon 14 flows toward the downstream direction and gradually cools and hardens.

In order to suppress deterioration caused by heat, the upper roller 40 may have a refrigerant flow path inside. The refrigerant such as water flowing through the refrigerant flow path absorbs and transports the heat of the upper roll 40 to the outside, thereby cooling the upper roll 40.

The partition wall 42 divides the forming space 50 into the high temperature space 51 on the upstream side and the low temperature space 52 on the downstream side as shown in FIG. 1, and restricts the flow of gas from the high temperature space 51 to the low temperature space 52. The partition wall 42 may extend from an upper side wall 32 to the other upper side wall 33 as shown in FIG. 3, and may traverse the forming space 50.

Since the high temperature space 51 has a high temperature as compared with the low temperature space 52, it contains a large amount of gas evaporated by the molten metal 11 in the bath 20. The gas contains a metal element evaporated from the molten metal 11 in the form of at least one of a monomer and a compound. The compound may, for example, be a metal oxide or a metal sulfide. Hereinafter, this gas is referred to as a metal-containing gas.

The partition wall 42 restricts the flow of the metal-containing gas from the high temperature space 51 to the low temperature space 52. The amount of foreign matter such as droplets or particles which can be formed by cooling of the metal-containing gas in the low temperature space 52 can be reduced. As a result, the number of defects generated by the foreign matter falling on the surface of the glass ribbon 14 can be reduced.

The high temperature space 51 and the low temperature space 52 are supplied with gas from the outside of the forming apparatus 10 via the air supply passages 34 formed in the respective top walls. In order to restrict oxidation of the exposed portion of the liquid surface of the molten metal 11, the gas may be a reducing gas. The reducing gas contains, for example, 1 to 15% by volume of hydrogen and 85 to 99% by volume of nitrogen. The reducing gas is preheated in the preheating space 53 surrounded by the roof casing 31 and the top wall 30, and then supplied to the high temperature space 51 and the low temperature space 52 via the air supply passage 34. Further, the gas in the preheating space 53 flows into the forming space 50 not only through the air supply passage 34 but also through the joint of the brick forming the top wall 30 or the like.

Further, in the high temperature space 51 and the low temperature space 52 of the present embodiment, the same type of gas is supplied through the air supply passages 34 formed in the respective top walls, but different types of gases may be supplied.

The high temperature space 51 may be supplied with gas from the outside of the forming apparatus 10 via a chute space 27 formed between the flow path control shutter 23 and the inlet wall 26 in addition to the air supply passage 34 formed in the top wall thereof.

For the chute space 27, gas may be supplied from at least one of the upper side and the side. The gas may be any one of an inert gas and a reducing gas. An exhaust passage is not connected to the chute space 27, and most of the gas supplied to the chute space 27 is supplied to the high temperature space 51 through the lower side of the inlet wall 26.

An exhaust passage 44 is formed in a side wall of the high temperature space 51 (ie, the upper side walls 32, 33). The exhaust passage 44 discharges the gas of the high temperature space 51 to the outside of the forming apparatus 10. The outside of the molding apparatus 10 may be hereinafter referred to as the outside of the molding space 50. The exhaust passage 44 can discharge the gas by using a difference in air pressure between the high temperature space 51 and the outside of the molding apparatus 10, or can discharge the gas by a suction force such as a pump. Further, the exhaust passage 44 may be formed not only on the side wall of the high temperature space 51 but also on the side wall of the low temperature space 52.

Next, a method of manufacturing a floating glass using the floating glass apparatus having the above configuration will be described with reference to FIGS. 1 to 3 again.

The floating glass manufacturing method includes a forming step of forming the glass ribbon 14 into a plate shape even if it flows on the liquid surface of the molten metal 11 in the bath 20. In the forming step, the upper roller 40 presses the end portion in the width direction of the glass ribbon 14 passing between the liquid surface of the molten metal 11 and the inlet wall 26, and the upper roller 40 rotates to cause the glass ribbon 14 to flow in the downstream direction.

However, as shown in FIG. 2, on the upstream side of the inlet wall 26, the entire liquid surface of the molten metal 11 is covered by the glass ribbon 14, so that the amount of the metal-containing gas is small. On the other hand, on the downstream side of the inlet wall 26, a part of the liquid surface of the molten metal 11 is not covered by the glass ribbon 14, and therefore the amount of the metal-containing gas is large. Therefore, the partition wall 42 is disposed at the entrance The wall 26 is further downstream. The high temperature space 51 on the upstream side of the partition wall 42 can capture a large amount of metal-containing gas.

Further, in the vicinity of the upper roller 40, the airflow is liable to become unstable. The reason why the airflow becomes unstable is, for example, the incorporation of the cold external air from the through hole of the upper side wall 32 through which the rotating shaft of the upper roller 40 is inserted, and the temperature of the upper roller 40 and its periphery by the cooling of the refrigerant. Poor and so on. Therefore, the partition wall 42 is disposed on the most upstream upper roller 40 among the plurality of upper rollers 40 arranged at intervals in the flow direction of the glass ribbon 14 (hereinafter, referred to as "the most upstream roller 40" ") on the upstream side. The gas flow in the vicinity of the partition wall 42 can be stabilized, and the metal-containing gas trapped in the high temperature space 51 can be suppressed from flowing out to the low temperature space 52.

As described above, the partition wall 42 is disposed on the downstream side of the inlet wall 26 and disposed on the upstream side of the uppermost upstream roller 40. Thereby, the high temperature space 51 on the upstream side of the partition wall 42 can capture a large amount of metal-containing gas, and can suppress the metal-containing gas trapped in the high temperature space 51 from flowing out to the low temperature space 52.

Further, the partition wall 42 may be disposed in the range Z of the viscosity of the glass ribbon 14 in the flow direction of the glass ribbon 14 as shown in Fig. 2 of 10 ^4.9 to 10 ^5.6 dPa ‧ s. When the partition wall 42 is disposed in the above range Z, the partition wall 42 can be disposed at a position sufficiently far from the upstream side of the most upstream upper roller 40, so that the airflow in the vicinity of the partition wall 42 can be easily stabilized. In particular, when the thickness of the floating glass is 2 mm or less, preferably 1 mm or less, and more preferably 0.7 mm or less, it is effective in terms of stabilizing the gas flow. The thinner the thickness of the floating glass becomes, the more the number of upper rolls 40 used becomes to stretch the glass ribbon 14 to be thinner. In this case, if the partition wall 42 is disposed in the above range Z, the partition wall 42 can be disposed at a position sufficiently far from the upstream side of the most upstream upper roller 40, so that the airflow in the vicinity of the partition wall 42 is easily stabilized. Chemical. Further, when the partition wall 42 is disposed in the above range Z, the partition wall 42 can be disposed at a position sufficiently far from the downstream side of the inlet wall 26, so that the high temperature space 51 on the upstream side can capture a large amount of gas containing metal. Preferably, the partition wall 42 has a viscosity of 10 ^4.9 to 10 ^5.5 dPa ‧ in the flow direction of the glass ribbon 14 , and more preferably 10 ^5.0 to 10 ^5.4 in the glass ribbon 14 . The scope of dPa‧s.

Between the partition wall 42 and the inlet wall 26, the ratio of the exposed portion of the molten metal 11 that is not covered by the glass ribbon 14 may be 10 to 40%. If the ratio of the exposed portion is 10% or more, the high-temperature space 51 formed between the partition wall 42 and the inlet wall 26 can sufficiently capture the metal-containing gas. Further, when the ratio of the exposed portion is 40% or less, deterioration of the heater 36 caused by the metal-containing gas can be suppressed. Between the partition wall 42 and the inlet wall 26, the ratio of the exposed portion of the molten metal 11 to the liquid surface of the molten metal 11 is preferably from 10 to 35%, more preferably from 10 to 20%.

Further, the partition wall 42 may be disposed in the horizontal direction (X-direction distance) L1 between the upstream end of the inlet wall 26 and the upstream end of the partition wall 42 as the upstream end and the outlet wall 28 of the inlet wall 26 as shown in FIG. The X direction between the upstream ends is 5 to 20% of the distance L2. If the distance L1 is 5% or more of the distance L2, the high-temperature space 51 formed between the partition wall 42 and the inlet wall 26 can sufficiently capture the metal-containing gas. Moreover, when the distance L1 is 20% or less of the distance L2, the partition wall 42 can be disposed at a position sufficiently far from the upstream side of the most upstream upper roller 40. The distance L1 is preferably 5 to 15% of the distance L2, more preferably 5 to 10% of the distance L2.

The partition wall 42 protrudes downward from the top wall 30. The height H1 (see FIG. 3) of the lower end of the partition wall 42 is, for example, 10 to 40% of the height H2 (see FIG. 1) below the top wall 30, based on the exposed portion of the liquid surface of the molten metal 11. If the height H1 of the lower end of the partition wall 42 is 10% or more of the height H2 below the top wall 30, the glass ribbon downstream of the partition wall 42 can be monitored from the most upstream of the forming space 50. Further, if the height H1 of the lower end of the partition wall 42 is 40% or less of the height H2 below the top wall 30, the metal-containing gas can be left in the high temperature space 51, so that the metal-containing gas can be reduced from the high temperature space 51. It flows out to the low temperature space 52. The height H1 of the lower end of the partition wall 42 is preferably 10 to 35% of the height H2 below the top wall 30, and more preferably 10 to 20% of the height H2 below the top wall 30.

In order to make the height H1 variable, the partition wall 42 can be moved in the up and down direction with respect to the top wall 30. As shown in FIG. 1 and FIG. 3, for example, a connecting rod 46 is coupled to the partition wall 42 and the top wall is The nut 47 is kept free to rotate on the outer casing 31. When the nut 47 is rotated, the connecting rod 46 screwed to the nut 47 moves in the vertical direction, and as a result, the partition wall 42 moves in the vertical direction.

In the high-temperature space 51, the discharge amount Qout of the gas to the outside of the molding apparatus 10 is preferably 100% or more of the supply amount Qin of the gas from the outside of the molding apparatus 10, more preferably 170% or more of the supply amount Qin, and further preferably More than 230% of the supply.

Here, "Qin" means a normal flow rate (Nm ³ /hr) of gas supplied to the high temperature space 51 from at least one of the upper side, the side, and the upstream (in the present embodiment from the upper side and the upstream side). Qin does not include the supply of gas from the downstream. The reason why Qin includes the supply amount of gas from the upstream (i.e., the chute space 27) is that most of the gas supplied from the outside of the forming device 10 to the chute space 27 is directly supplied to the high temperature space 51. Further, when gas is supplied from the side direction high temperature space 51, an air supply passage can be provided in the upper side walls 32, 33.

On the other hand, Qout means a normal flow rate (Nm ³ /hr) of the gas discharged from at least one of the upper side and the side (the side in the present embodiment) from the high temperature space 51. Qout does not include the amount of gas discharged downstream and upstream. Furthermore, the amount of gas discharged upstream (i.e., the chute space 27) is a small amount. The reason for this is that an exhaust passage is not connected to the chute space 27. Further, when the gas is discharged upward from the high temperature space 51, an exhaust passage may be provided in the top wall 30.

When the discharge amount is equal to the supply amount, there is almost no gas entering and leaving between the high temperature space 51 and the low temperature space 52, and almost no metal-containing gas flows out from the high temperature space 51 to the low temperature space 52.

Moreover, when the discharge amount is more than the supply amount, the gas is supplied from the low temperature space 52 to the high temperature space 51. Therefore, a gas flow from the low temperature space 52 to the high temperature space 51 is formed, which suppresses the outflow of the metal-containing gas from the high temperature space 51 to the low temperature space 52.

The float glass produced can be, for example, an alkali-free glass. The alkali-free glass is substantially free of glass of an alkali metal oxide (Na ₂ O, K ₂ O, Li ₂ O, etc.). The total amount of the alkali metal oxide in the alkali-free glass may be 0.1% by mass or less.

The alkali-free glass is, for example, represented by mass % of oxide, and contains SiO ₂ : 50 to 73%, Al ₂ O ₃ : 10.5 to 24%, B ₂ O ₃ : 0 to 12%, MgO: 0 to 8%, and CaO. : 0 to 14.5%, SrO: 0 to 24%, BaO: 0 to 13.5%, ZrO ₂ : 0 to 5%, and MgO + CaO + SrO + BaO: 8 to 29.5%.

In the case of taking into account a higher strain point and a higher solubility, the alkali-free glass is preferably represented by mass % of oxide and contains SiO ₂ : 58 to 66%, and Al ₂ O ₃ : 15 to 22%. , B ₂ O ₃ : 5~12%, MgO: 0~8%, CaO: 0~9%, SrO: 3~12.5%, BaO: 0~2%, MgO+CaO+SrO+BaO: 9~18 %.

In particular, in the case where a higher strain point is to be obtained, the alkali-free glass is preferably represented by mass % of the oxide and contains SiO ₂ : 54 to 73%, Al ₂ O ₃ : 10.5 to 22.5%, and B _{2 .} O ₃ : 0 to 5.5%, MgO: 0 to 8%, CaO: 0 to 9%, SrO: 0 to 16%, BaO: 0 to 2.5%, and MgO + CaO + SrO + BaO: 8 to 26%.

The forming temperature of the alkali-free glass is higher than the molding temperature of the usual soda lime glass by 100 ° C or more. Therefore, the amount of the metal-containing gas evaporated by the molten metal 11 is large, and the partition wall 42 suppresses the flow of the metal-containing gas from the high temperature space 51 to the low temperature space 52.

In the above, the embodiment of the floating glass manufacturing method and the floating glass manufacturing apparatus has been described. However, the present invention is not limited to the above-described embodiment and the like, and can be carried out within the scope of the gist of the present invention described in the claims. Various changes and improvements.

The present application claims the priority of Japanese Patent Application No. 2013-171982, filed on Jan. 22, 2013, to the Japanese Patent Office, the entire contents of .

10‧‧‧Forming device

11‧‧‧ molten metal

12‧‧‧ molten glass

14‧‧‧glass ribbon

20‧‧‧ bath

22‧‧‧ chute

23‧‧‧Flow channel control gate

24‧‧‧Limited bricks

26‧‧‧ entrance wall

27‧‧‧ chute space

28‧‧‧Exit wall

30‧‧‧ top wall

31‧‧‧Top wall housing

34‧‧‧ gas supply path

36‧‧‧heater

40‧‧‧Upper roll

42‧‧‧ partition wall

46‧‧‧ Connecting rod

47‧‧‧ Nuts

50‧‧‧Forming space

51‧‧‧High temperature space

52‧‧‧low temperature space

53‧‧‧Preheating space

H2‧‧‧ Height

L1‧‧‧ distance

L2‧‧‧ distance

X‧‧‧ direction

Claims (9)

A floating glass manufacturing apparatus comprising: a bath for containing molten metal; an inlet wall located above an upstream portion of the bath; an outlet wall located above a downstream portion of the bath; and a top wall configured to Above the bath and extending from the inlet wall to the outlet wall; a plurality of upper rolls are disposed at intervals along a flow direction of the glass ribbon flowing on the liquid surface of the molten metal, and are pressed through the liquid a widthwise end of the glass ribbon between the surface and the inlet wall and rotating by itself; a partition wall separating the forming space surrounded by the top wall, the bath, the inlet wall and the outlet wall into a high temperature space on the upstream side a low-temperature space on the downstream side; and an exhaust passage that discharges the gas in the high-temperature space to the outside of the forming space; and the partition wall is disposed on a downstream side of the inlet wall, and is disposed on the side The uppermost roller on the uppermost roller of the plurality of upper rollers is further upstream. The floating glass manufacturing apparatus according to claim 1, wherein the partition wall is disposed in a range in which the glass ribbon has a viscosity of 10 ^4.9 to 10 ^5.6 dPa ‧ in a flow direction of the glass ribbon. The floating glass manufacturing apparatus according to claim 1 or 2, wherein a ratio of an exposed portion of the molten metal surface which is not covered by the glass ribbon is 10 to 40% between the partition wall and the inlet wall. The floating glass manufacturing apparatus according to any one of claims 1 to 3, wherein the partition wall protrudes downward from the top wall, and The height of the lower end of the partition wall is 10 to 40% of the height below the top wall based on the exposed portion of the liquid surface of the molten metal. The floating glass manufacturing apparatus according to any one of claims 1 to 4, wherein the floating glass produced is an alkali-free glass. A method for producing a floating glass, characterized in that the gas in the high-temperature space is discharged to the outside of the forming space via the exhaust passage by using the floating glass manufacturing apparatus according to any one of claims 1 to 5. A floating glass manufacturing method using the floating glass manufacturing apparatus of claim 1, wherein the viscosity of the glass ribbon in the flow direction of the glass ribbon is in a range of 10 ^4.9 to 10 ^5.6 dPa ‧ next door. A floating glass manufacturing method using the floating glass manufacturing apparatus of claim 1, wherein a ratio of an exposed portion of the molten metal surface that is not covered by the glass ribbon is between the partition wall and the inlet wall 10~40%. A method of manufacturing a floating glass using the floating glass manufacturing apparatus of claim 1, and the manufactured floating glass is an alkali-free glass.