JP4766303B2 - Float plate glass manufacturing apparatus and float plate glass manufacturing method - Google Patents

Description

  The present invention relates to a structure, a float plate glass manufacturing apparatus, and a bubble floating suppression method and a float plate glass manufacturing method, and more particularly to a structure, a float plate glass manufacturing apparatus, and a bubble floating suppression suitable for manufacturing a plate glass as a molded product. The present invention relates to a method and a float plate glass manufacturing method.

  The apparatus for producing plate glass by the float process continuously supplies molten glass on a molten metal contained in a bathtub, for example, molten tin, and floats on the molten tin. At this time, the equilibrium thickness is reached or reached. An apparatus for producing a strip-shaped plate glass having a constant width by pulling the glass ribbon facing toward the outlet of the molten tin bath, that is, toward the layer (downstream annealing portion) provided adjacent to the outlet of the molten tin bath It is. In such an apparatus for producing sheet glass by the float process, in addition to pulling downstream, the upper surface of both edges of the molten glass ribbon that has reached or reached the equilibrium thickness on the molten tin is made of molten tin. A plate glass thinner than the equilibrium thickness is produced by stretching in the width direction by a rotating top roll over a predetermined length on the upstream side.

  In an apparatus for producing sheet glass using a top roll, undulation may occur on the glass surface when the top roll is stretched. Therefore, the molten glass ribbon level in the vicinity of the edge in the width direction of the molten glass ribbon without using such a top roll is set lower than the molten tin bath level in the vicinity thereof, so that the molten glass ribbon A plate glass manufacturing apparatus that prevents the sheet from being narrowed in the width direction and holds an edge has been proposed (for example, Patent Document 1).

  5 and 6 show a conventional example of a sheet glass manufacturing apparatus that performs the edge holding in a non-contact manner.

  In the plan view shown in FIG. 5, the molten glass ribbon 3 is caused to flow while being pulled in the layer direction (X direction in FIG. 5) on the molten tin 2 stored in the bathtub 1. The molten glass ribbon 3 tends to reach an equilibrium thickness when its edges 4 and 4 narrow or widen in the width direction of the molten glass ribbon 3 in the high temperature region of the molten tin bath. Here, edge holding when the edge 4 of the molten glass ribbon 3 is about to narrow in the width direction will be described.

  FIG. 6 is a cross-sectional view taken along the line CC in FIG. 5. In the same figure, a rod-like body 6, which is a L-shaped structure, is immersed in the molten tin 2 of the bathtub 1 along the edge of the molten glass ribbon. It is arranged in the state. The bowl-shaped body 6 includes a vertical channel 6B in which an upper opening 6A is formed and a horizontal channel 6D in which a lower opening 6C is formed. In addition, a linear motor 7 is installed at the bottom of the bathtub 1 and below the horizontal flow path 6D of the bowl-shaped body 6. A driving force (magnetic field) is applied to the molten tin 2 in the bowl-shaped body 6 by the linear motor 7. The molten tin 2 flows in the direction of arrow A. Thereby, since the flow of the molten tin 2 in the direction substantially perpendicular to the bath surface 5 and in the direction of arrow B toward the bottom of the bathtub 1 is generated, a negative pressure is generated below the edge 4 of the molten glass ribbon 3. Due to this negative pressure, the bath surface level of the molten tin 2 in the vicinity of the edge 4 becomes lower than the surrounding bath surface level. Then, the edge 4 of the molten glass ribbon 3 flows into the recessed portion 5 </ b> A of the lowered bath surface 5, and the lower part of the edge becomes a convex portion, and the thickness of the edge 4 becomes thicker than the central portion of the molten glass ribbon 3. Due to the thickness deviation of the edge 4, the force of the arrow E that causes the molten glass ribbon 3 to narrow in the width direction is not generated based on the surface tension, so the edge 4 of the molten glass ribbon 3 is held in the recess 5 </ b> A, and the equilibrium thickness Thin plate glass is produced.

By the way, as a material which forms the cage | basket-like body 6 which is a L-shaped structure immersed in the molten tin 2 of the bathtub 1, the reactivity with the molten tin 2 is low or it does not react, A high temperature range The high-temperature resistance at the time of forming the rod-like body 6 is excellent, the workability when forming the rod-like body 6 is excellent, and when the driving force is applied to the molten tin 2 by the linear motor 7, it is required to be non-magnetic. Graphite is preferable as the material that satisfies the conditions.
Japanese Patent Laid-Open No. 10-236832

  However, as shown in FIG. 7, when the graphite rod 6 is immersed in the molten tin 2, when the temperature of the molten tin 2 is about 900 ° C. or more, for example, oxygen or a small amount dissolved in the molten tin 2 Hydrogen and graphite react to generate gas. The generated gas is initially attached to the surface of the rod-shaped body 6 as small bubbles 8, but gradually increases to increase the buoyancy and float away from the rod-shaped body 6. The floated bubbles 8 may cause problems such as disturbing the molten glass ribbon 3, generating bubbles on the lower surface of the molten glass ribbon 3, and generating irregularities. In particular, it is a thin plate having a thickness of about 0.7 mm and has a great influence on FPD plate glass such as a liquid crystal display device that requires flatness.

  Such a problem is not limited to the production of the float process plate glass, but is also the same in the case of producing a metal plate or other plate material. It is a problem to be solved about the case.

  The present invention has been made in view of such circumstances, and a structure is immersed in a molten metal stored in a bathtub, and a dissolved gas in the molten metal reacts to generate gas. However, since it is possible to suppress the gas from rising into the molten metal as a bubble, a structure and a float plate glass manufacturing apparatus that can prevent the molded object molded on the molten metal from being caused by bubbles It is another object of the present invention to provide a method for suppressing bubble levitation and a method for producing float glass.

Immersed disposed molten metal retained in the bath tub, a said porous structure made of a material of the molten metal and the non-affinity (said do not react with molten metal or hard reaction), the structure things atmosphere therein (e.g., in the float glass manufacturing facility in the float bath, the same applies hereinafter) that has a cavity passage communicating is formed in the space.

According to the structure, releasing the interior of the structure, since a cavity passage communicating with the air space, the gas generated in the surface in contact with the molten metal of the outer surface of the structure through the hollow passage to the air space Is done. Accordingly, since it prevent the gas generated in the structure outer surface floats as bubbles, air bubbles in the molded product to be molded on the molten metal, Ru can be prevented from occurring uneven due to the air bubbles.

  The mechanism by which the generated gas is released to the atmospheric space through the hollow path is assumed as follows. While the pressure in the hollow passage communicating with the atmospheric space is almost atmospheric pressure, a pressure larger than the atmospheric pressure is applied in the molten metal in which gas is generated. Therefore, the gas in the bubbles permeates through the porous structure before the bubbles adhering to the surface of the structure rise from the structure due to the pressure difference between the hollow path and the molten metal. It moves to the road and is released to the atmospheric space through the hollow path.

  In addition, the atmospheric space said here is the space in the state of atmospheric pressure, and the gas component of atmospheric space does not matter.

The porosity of the pre-Symbol porous structure Ru 5-40% der. This is because if the porosity of the porous structure is less than 5%, the generated gas does not easily pass through the structure and move to the hollow path, and the generated gas is sufficiently prevented from rising as bubbles. It is because it cannot be done. On the other hand, if the porosity exceeds 40%, the strength of the structure is weakened and there is a risk of molten metal intrusion. Further, a more preferable range of the porosity is 20 to 30%.

Before SL wall thickness from the surface of the structure to the hollow path is 1mm or more, Ru der below 100 mm. This is because if the thickness from the surface of the structure to the hollow passage exceeds 100 mm and is too thick, the generated gas is difficult to move through the structure and move to the hollow passage, and the generated gas rises as bubbles. This is because it cannot be sufficiently suppressed. Moreover, it is because the intensity | strength of a structure cannot be ensured if thickness is less than 1 mm. The thickness from the surface of the structure to the hollow path in this case refers to the thickness represented by the distance from the surface of the structure to the hollow path.
The thickness is more preferably 1.5 mm or more and 50 mm or less, and most preferably 2 mm or more and 30 mm or less.

Before Symbol structure, graphite and material. With structure was made of black lead, not reactive low or reaction with the molten metal, also better high temperature resistance in a high temperature range and is excellent further in the processability.

The communication port portion which communicates with the atmosphere space before Symbol structure (portion where the structure is projected to the atmosphere), the oxygen in the air space by the oxidation protective member formed of a hard material to oxidation than said structure that it has been protected from. This is because, when the communication port portion communicating with the atmospheric space of the structure is constantly in contact with oxygen in the atmospheric space, the structure of the communication port portion is oxidized and eroded, and the communication port portion is molten metal for a long period of time. There is a risk of being buried inside. If the communication port is buried in the molten metal, the hollow path will not communicate with the atmospheric space, so the generated gas will not pass through the structure and move to the hollow path, and the generated gas will rise as bubbles. It is because it becomes impossible to suppress. As the material of the oxidation protection member, brick or ceramic materials such as silicon carbide (SiC), silicon nitride (SiN), or a composite material thereof can be preferably used.

In order to achieve the above object, the present invention continuously supplies molten glass onto a molten metal surface of the molten metal bath in which molten metal is stored to form a molten glass ribbon, and the glass ribbon is formed on the molten metal surface. Is a device for manufacturing a plate glass having a target thickness by floating, forming a recess in the bath surface by sucking molten metal in a substantially vertical direction along the edge of the molten glass ribbon, and forming the edge in the recess. In the float sheet glass manufacturing apparatus for forming into the sheet glass while flowing and holding, in order to form the recess, a porous structure made of a material having a non-affinity with the molten metal is immersed and arranged during the melting of the metal, said structure together with hollow passage communicating with the air space is formed therein, wherein Ri gutter-like bodies der to hold the edges of the molten glass ribbon without contact, the molten metal of the outer surface of said structure Providing float glass manufacturing apparatus for guiding a gas generated in the contact surface to the cavity passage. This bowl-like body forms a recess in the bath surface by sucking the molten metal in the substantially vertical direction along the edge of the molten glass ribbon, and holds the edge in a non-contact manner by flowing the edge into the recess. This is because the flatness of the plate glass is impaired when a contact-type holding means such as a top roll is used to hold the edge of the molten glass ribbon, so that the non-contact type described above with reference to FIGS. 5 and 6 is used. It is preferable to use a rod-shaped body that is a holding means. However, graphite is used as the material of the rod-like material in terms of non-reactivity with molten metal, high-temperature resistance, ease of processing, non-magnetic properties, etc. The gas reacts with dissolved gas in the molten metal, for example, oxygen or hydrogen to generate gas. Further, when the structure is a bowl-like body, the bowl-like body is near the edge of the molten glass ribbon. Therefore, when the bubbles rise, there are many opportunities for the bubbles to collide with the molten glass ribbon, so that the effect of the present invention is particularly effectively exhibited. Therefore, since the generation | occurrence | production of the unevenness | corrugation by a bubble can be suppressed in the plate glass shape | molded, the plate glass excellent in surface flatness and plate | board thickness stability can be manufactured.

Immersed disposed molten metal retained in the bath tank, the interior of the porous structure made of a material of the molten metal and the non-affinity, hollow passage communicating with the air space is formed, said structure by directing gas generated in at the surface in contact with the molten metal of the outer surface in the cavity path, it suppresses the floats as bubbles in the structure outer surface.

In order to achieve the above object , the present invention continuously supplies molten glass onto a molten metal surface of the molten metal bath in which molten metal is stored to form a molten glass ribbon, and the glass ribbon is formed on the molten metal surface. In which a concave portion is formed in the bath surface by sucking molten metal in a substantially vertical direction along the edge of the molten glass ribbon, and the edge is formed in the concave portion. In the float sheet glass manufacturing method of forming into a sheet glass while being allowed to flow and hold, in order to form the concave portion, a porous structure made of a material having an affinity for the molten metal is immersed in the molten metal, The gas generated on the surface in contact with the molten metal on the outer surface of the structure is guided into a hollow path formed inside the structure, and the bubbles are prevented from rising as bubbles on the outer surface of the structure. Providing float glass manufacturing method characterized by the production of glass.

  According to the present invention, the molten glass is continuously supplied onto the molten metal surface of the molten metal bath in which the molten metal is stored to form the molten glass ribbon, and the molten metal is substantially removed along the edge of the molten glass ribbon. A concave portion is formed on the bath surface by sucking in the vertical direction, and the edge is poured into the concave portion and formed into a sheet glass while being held. In order to form this recess, a porous structure made of a material that is incompatible with the molten metal is immersed in the molten metal, but gas is generated on the outer surface of the structure in contact with the molten metal. Therefore, the generated glass is produced while guiding the generated gas into a hollow path formed inside the structure and suppressing bubbles from rising on the outer surface of the structure. Thereby, since the generated gas floats as a bubble and does not collide with the molten glass ribbon, there is no problem with the molten glass ribbon.

  According to the structure and float plate glass manufacturing apparatus, the bubble levitation suppression method and the float plate glass manufacturing method according to the present invention, the structure immersed in the molten metal stored in the bathtub, particularly in the molten tin, Even when dissolved gas in the metal reacts to generate gas, the gas can be suppressed from rising as bubbles. Thereby, it can be prevented that the molded object shape | molded on a molten metal is damaged by a bubble.

  Therefore, if the present invention is applied to the production of plate glass by the float process, a plate glass excellent in surface flatness and plate thickness stability can be produced.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a structure and float plate glass manufacturing apparatus, a bubble levitation suppression method, and a float plate glass manufacturing method according to the present invention will be described in detail below with reference to the accompanying drawings.

  FIG. 1 shows a plan view of a float glass sheet manufacturing apparatus 10. Glass for FPD such as liquid crystal is generally required to have a thickness of about 0.7 mm, and flatness is also required with high accuracy. As the plate glass manufacturing apparatus 10, a float plate glass manufacturing apparatus 10 of a type that holds the edge 22 using the rod-like body 12 in a non-contact manner is applied. According to this float plate glass manufacturing apparatus 10, it is required as a plate glass for FPD. A plate glass satisfying the plate thickness and flatness can be produced.

  A bowl-shaped body 12 (structure) of the float glass manufacturing apparatus 10 is disposed below the molten glass ribbon 20 of the bathtub 14 shown in FIG. 2 and is immersed in molten tin (molten metal) 16 stored in the bathtub 14. At the same time, it is disposed along both edges 22 and 22 of the molten glass ribbon 20 continuously supplied from the molten glass furnace to the supply port 18 shown in FIG. Further, the molten glass ribbon 20 advances while being pulled on the molten tin surface in the layer direction, which is the X direction in FIG. 1, and the high temperature region of the molten glass ribbon 20 in the bathtub 14 (about 930 to 1300 ° C. for soda lime glass). ) And the forming zone (about 800 to about 930 ° C. for soda lime glass), the edges 22 and 22 are held in the recess 26 of the bath surface 24 (FIG. 2). Further, the molten glass ribbon 20 having the edges 22 and 22 held by the recesses 26 is adjusted in plate thickness and width, and thereafter is sent to the subsequent stage of the bathtub in a stable state, cooled and sent to the layer. Note that the glass of the embodiment is soda lime, and the molten tin 16 in the high temperature range is heated by an electric heater. The bathtub 14 is made of refractory bricks.

  2 is a cross-sectional view taken along line FF in FIG. As shown in these drawings, the bowl-shaped body 12 is formed in a substantially L-shaped cross section, and a vertical flow path 30 in which an upper opening 28 is formed and a horizontal flow path 34 in which a lower opening 32 is formed. It consists of. In addition, a linear motor 40 is installed at the bottom of the bathtub 14 below the horizontal flow path 34 of the bowl-shaped body 12, and a driving force is applied to the molten tin 16 in the horizontal flow path 34 by the linear motor 40. 16 flows in the direction indicated by the arrow H in the vertical flow path 30 and the horizontal flow path 34 of the bowl-shaped body 12. By this operation, a flow of the molten tin 16 is generated in a direction substantially perpendicular to the bath surface 24 and toward the bottom of the bathtub 14, so that a negative pressure is generated below the edge 22 of the molten glass ribbon 20, Due to this negative pressure, the liquid level of the molten tin 16 in the vicinity of the edge 22 becomes lower than the surrounding liquid level. Then, the edge 22 of the molten glass ribbon 20 flows into the recessed portion 26 of the lowered bath surface 24. Thereby, since the edge 22 of the molten glass ribbon 20 is held in the concave portion, it is possible to widen the molten glass ribbon (preventing the molten glass ribbon from narrowing in the width direction) and maintain the wide state thereof, A sheet glass thinner than the equilibrium thickness is produced.

  The linear motor 40 has an advantage that the molten tin 16 can be directly driven and the flow rate control is easy. The linear motor 40 forms a coil on a comb-shaped primary iron core, applies a three-phase AC voltage to the coil, and sequentially magnetizes the coil to generate a magnetic field that moves in a certain direction. The linear motor 40 is disposed below the bottom surface of the bathtub 14 of the bowl-shaped body 12 and is positioned so as to apply a driving force (biasing force) to the molten tin 16 in the horizontal flow path 34 of the bowl-shaped body 12. Is arranged. As a result, the molten tin 16 in the vertical flow path 30 and the horizontal flow path 34 flows from immediately below the edge 22 of the molten glass ribbon 20 toward the side wall 15 of the bathtub 14 as indicated by an arrow H by the driving force of the linear motor 40. Then, the direction of flow is changed as shown by arrow I. Further, the molten tin 16 in the edge bathtub 14A and the molten tin 16 in the central bathtub 14B are guided to the upper opening 28 side by the suction force generated in the upper opening 28 of the vertical flow path 30, and the upper part. Sucked into the opening 28. Accordingly, a stable recess 26 is formed in the bath surface 24 and the shape of the edge 22 is stabilized, so that the edge 22 is stably held in the recess 26.

  As the material for forming the rod-shaped body 12, the reactivity with the molten tin 16 is low or non-reactive, the high temperature resistance in a high temperature range is good, and the workability when forming the rod-shaped body 12 is excellent. In addition, since the magnetic field is applied to the rod-shaped body 12 by the linear motor 40, it is required to be non-magnetic, and graphite is generally used as a material that satisfies these conditions.

  However, when the graphite rod 12 is immersed in the molten tin 16, when dissolved gas is present in the molten tin, the molten tin 16 is dissolved in a small amount in the molten tin 16 at a temperature of about 900 ° C. or higher. A dissolved gas such as oxygen or hydrogen reacts with graphite to generate a gas. The generated gas is initially attached to the outer surface of the rod-shaped body 12 as small bubbles 46 (see FIG. 4), but gradually increases to increase buoyancy, and floats away from the outer surface of the rod-shaped body 12. When the air bubbles 46 that have risen reach the lower surface of the molten glass ribbon 20, bubbles are generated on the lower surface of the molten glass ribbon 20, irregularities are generated, and other defects occur, resulting in defects in the formed plate glass. There is a risk of letting it.

  Therefore, in the present invention, a hollow passage communicating with the atmospheric space is formed inside the porous graphite-made body 12 having a porosity of 5 to 40% and immersed in the molten tin 16 stored in the bathtub 14. 42 (42A, 42B, 42C) is formed, and the gas generated by the hollow passage 42 is prevented from rising as bubbles 46.

  FIG. 3 is a cross-sectional view taken along the line KK in FIG.

  As shown in FIG. 3, the vertical direction of the vertical hollow path 42A in the vertical direction, the horizontal horizontal path 42B in the vertical direction, and the plane including the vertical hollow path 42A and the horizontal hollow path 42B is provided inside the rod-shaped body 12. A hollow path 42 formed of orthogonal hollow paths 42C (in the front and back direction in FIG. 3) is formed. The orthogonal hollow path 42 </ b> C is formed in the lower part of the edge 22 of the molten glass ribbon 20 in the cage 12. This is because when the reacted gas floats as bubbles below the edge 22 of the molten glass ribbon 20, there are many opportunities for the bubbles to collide with the lower surface of the sheet glass to be formed. Further, a protruding portion 12A protruding on the bath surface 24 of the molten tin 16 is formed in a portion of the rod-shaped body 12 away from the edge 22, and the hollow passage 42 communicates with the atmospheric space in the protruding portion 12A. A communication port 42D is formed. Thereby, the bowl-shaped body 12 which is a structure provided with the bubble floating suppression function is formed.

  Thus, by forming the hollow passage 42 inside the rod-shaped body 12, the gas generated by the reaction between oxygen or hydrogen dissolved in the molten tin 16 and graphite as the material of the rod-shaped body 12 is melted. It is possible to suppress the bubbles from rising as bubbles 46 in the tin. Thereby, it is possible to prevent the glass plate formed on the molten tin 16 from having a defect due to the bubbles 46.

It is surmised that the mechanism by which the generated gas is released into the atmospheric space through the cavity 42 will be the following mechanism. That is, the rod-shaped body 12 made of graphite has porosity. Further, by forming the hollow passage 42 communicating with the atmospheric space inside the rod-shaped body 12, the hollow passage 42 becomes almost atmospheric pressure. On the other hand, in the molten tin 16 where gas is generated, the weight of the molten tin 16 corresponding to the depth of the location where the gas is generated is added to the atmospheric pressure. Great pressure is applied. The pressure difference between the hollow passage 42 and the molten tin 16 causes the gas in the bubbles 46 to flow before the bubbles 46 adhering to the surface of the rod-shaped body 12 float away from the surface of the rod-shaped body 12. As indicated by an arrow K, it is assumed that the porous rod-shaped body 12 passes through the porous channel 12 and moves to the hollow channel 42 and is discharged from the communication port 42D to the atmospheric space on the bath surface 24 through the hollow channel 42 in FIG. The In this case, the porosity of the rod-shaped body 12 made of graphite is preferably 5 to 40%. The reason for this is that if the porosity of the rod-shaped body 12 is less than 5%, the gas in the bubbles does not easily pass through the rod-shaped body 12 and move to the hollow passage 42, and the generated gas rises as bubbles. This is because it cannot be sufficiently suppressed. On the other hand, if the porosity exceeds 40%, the strength of the rod-shaped body 12 becomes weak, and there is a risk of intrusion of molten tin. Further, a more preferable range of the porosity is 20% to 30%. Furthermore, the thickness of the wall from the surface of the bowl-shaped body 12 to the cavity 42 is preferably in the range of 1 to 100 mm, more preferably 1.5 to
It is in the range of 50 mm, most preferably in the range of 2-30 mm. The reason for this is that if the thickness from the surface of the rod-shaped body 12 to the cavity portion 42 exceeds 100 mm, the gas in the bubbles 8 does not easily pass through the rod-shaped body 12 and move to the cavity path 42. This is because it is not possible to sufficiently suppress the gas to rise as bubbles. Moreover, if the wall thickness is less than 1 mm, the strength of the heel state 12 cannot be secured. In this case, the thickness from the surface of the bowl-shaped body 12 to the cavity portion 42 refers to the thickness represented by the distance from the surface of the bowl-shaped body 12 to the cavity path 42.

  Although not shown in FIG. 3, suction means is connected to the communication port 42 </ b> D to create a negative pressure in the cavity 42, thereby actively increasing the pressure difference between the cavity 42 and the molten tin 16. You may do it. Moreover, the cross-sectional shape of the hollow path 42 is not particularly limited, and may be an arbitrary shape.

  By the way, if tin oxide generated by oxidation of the molten tin 16 on the bath surface 24 adheres to the plate glass, it becomes a factor of the defects of the plate glass. Therefore, the atmospheric space on the bath surface 24 is a mixture of nitrogen gas and hydrogen gas. It is preferable to form a non-oxygen atmosphere by gas. However, even in this case, a slight amount of oxygen remains in the mixed gas, and further, there is also intrusion from the outside. Therefore, the graphite of the protruding portion 12A in which the communication port 42D is formed is oxidized and eroded, The protruding portion 12A is buried in the molten tin 16 for a long period. When the protrusion 12A is buried in the molten tin 16, it is sealed with molten tin and the cavity 42 is not communicated with the atmospheric space, so that the generated gas does not pass through the rod-shaped body 12 and move to the cavity 42, It becomes impossible to suppress the generated gas from rising as bubbles. The atmospheric space is generally the space of the air layer, but the atmospheric space here is used to mean a space in a pressure state of atmospheric pressure, and the gas component in the atmospheric space is a problem. do not do.

  Therefore, in the present invention, the protruding portion 12A of the rod-shaped body 12 is protected from oxygen by the oxidation protection cap 44 formed of a material that is harder to oxidize than graphite. The oxidation protection caps 44 are respectively provided on the protrusions 12A of the rod-shaped body 12, and FIG. 1 shows a plurality of oxidation protection caps 44 exposed from the bath surface 24 of the molten tin 16 to the atmospheric space.

  As a material of the oxidation protection cap 44, for example, a brick or ceramic material, particularly silicon carbide (SiC) or silicon nitride (SiN) can be preferably used. Further, the oxidation protection cap 44 is formed in, for example, a reverse concave shape, and a through hole 44A that connects the communication port 42D formed in the protruding portion 12A of the rod-shaped body 12 and the atmospheric space is formed. A screw is engraved on the inner peripheral surface of the oxidation protection cap 44, and is screwed into a screw engraved on the outer peripheral surface of the protruding portion 12A. As a result, the protrusion 12A protruding on the bath surface 24 is protected from oxygen by the oxidation protection cap 44, so that the protrusion 12A is prevented from being eroded by oxygen remaining in the mixed gas. The coupling between the oxidation protection cap 44 and the protruding portion 12A is not limited to the screw structure, and any method may be used as long as the coupling can be performed so that no gap is formed in the coupling portion.

  In the embodiment of the present invention, the example of the float glass plate manufacturing apparatus for manufacturing plate glass has been described as the molded product manufacturing apparatus. However, the present invention is not limited to the plate glass manufacturing apparatus. The present invention is a porous structure formed of a material in which a structure immersed in a molten metal stored in a bathtub reacts with a dissolved gas in the molten metal to generate a gas. It can be applied to all cases where there is a problem if the gas that rises as bubbles rises.

The top view which showed the manufacturing apparatus of the FPD plate glass for liquid crystals in embodiment of the manufacturing apparatus of the molding of this invention Sectional drawing of the rod-shaped body seen from the FF line of FIG. Sectional drawing of the rod-shaped body seen from the KK line of FIG. Explanatory drawing of the mechanism of suppression of bubble levitation by the hollow passage formed inside the rod-shaped body Plan view of conventional float glass manufacturing equipment Sectional view seen from CC line of FIG. Explanatory drawing explaining the malfunction of plate glass by the graphite reacting with oxygen dissolved in molten tin reacting with oxygen to generate gas, and the generated gas rises as bubbles

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Plate glass manufacturing apparatus, 12 ... Rod-like body, 12A ... Protruding part, 14 ... Bath, 16 ... Molten tin, 18 ... Supply port, 20 ... Molten glass ribbon, 22 ... Edge, 24 ... Bath surface, 26 ... Recessed part, 28 ... upper opening, 30 ... vertical flow path, 32 ... lower opening, 34 ... horizontal flow path, 40 ... linear motor, 42 ... hollow path, 42A ... vertical hollow path, 42B ... horizontal hollow path, 42C ... orthogonal cavity Road, 44 ... Oxidation protection cap, 46 ... Air bubbles

Claims (8)

A molten glass is continuously supplied onto the molten metal surface of the molten metal bath in which the molten metal is stored to form a molten glass ribbon, and the glass ribbon is floated on the molten metal surface to produce a plate glass having a target thickness. Float plate glass, which is a device that forms a recess in a bath surface by sucking molten metal in a substantially vertical direction along an edge of the molten glass ribbon, and forms the plate while allowing the edge to flow into and hold the recess. In manufacturing equipment,
In order to form the concave portion, a porous structure made of a material having a non-affinity with the molten metal is immersed during the melting of the metal, and a hollow path communicating with the air space is formed in the structure. In addition, it is a saddle-like body that holds the edge of the molten glass ribbon in a non-contact manner, and guides the gas generated on the outer surface of the structure in contact with the molten metal into the hollow passage. Float glass manufacturing equipment. The apparatus for producing a float sheet glass according to claim 1, wherein the thickness of the wall from the surface of the structure to the hollow path is 1 mm or more and 100 mm or less. The apparatus for producing a float sheet glass according to claim 1, wherein the thickness of the wall from the surface of the structure to the hollow path is 1.5 mm or more and 50 mm or less. The apparatus for producing a float sheet glass according to claim 1, wherein the thickness of the wall from the surface of the structure to the hollow path is 2 mm or more and 30 mm or less. A molten glass is continuously supplied onto the molten metal surface of the molten metal bath in which the molten metal is stored to form a molten glass ribbon, and the glass ribbon is floated on the molten metal surface to produce a plate glass having a target thickness. A float plate glass that forms a recess in a bath surface by sucking a molten metal in a substantially vertical direction along an edge of the molten glass ribbon, and forms the plate glass while allowing the edge to flow into and hold the recess. In the manufacturing method,
In order to form the concave portion, a porous structure made of a material that is incompatible with the molten metal is immersed in the molten metal, and a gas generated on the surface of the outer surface of the structure in contact with the molten metal In the hollow path formed inside the structure, and the plate glass is manufactured while suppressing bubbles from rising as bubbles on the outer surface of the structure. 6. The method for producing a float sheet glass according to claim 5, wherein the wall thickness from the surface of the structure to the hollow path is 1 mm or more and 100 mm or less. The float sheet glass manufacturing method according to claim 5, wherein a thickness of a wall from a surface of the structure to the hollow path is 1.5 mm or more and 50 mm or less. 6. The method for producing a float sheet glass according to claim 5, wherein the wall thickness from the surface of the structure to the hollow path is 2 mm or more and 30 mm or less.

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