JP5397736B2 - Float glass manufacturing apparatus and float glass manufacturing method - Google Patents

Description

  The present invention relates to a float glass manufacturing apparatus and a manufacturing method thereof, and more particularly to an apparatus and a method for manufacturing a glass plate by a float process.

  As is well known, a glass substrate for a flat panel display (FPD) typified by a plasma display (PDP) and a liquid crystal display (LCD) is manufactured from a single piece of glass plate called mother glass. In fact, with the recent increase in the size of glass substrates for FPDs, the increase in size of mother glass is inevitably promoted.

  As a method for producing a glass plate which is a mother glass, a molten glass is stored on the bath surface of a float bath, and molten glass is continuously supplied from the upstream side to form a glass ribbon while downstream of the float bath. A float method in which a glass ribbon after molding is drawn from the end is widely used.

  In this type of float process, it is customary to use tin as the molten metal, but this tin is not only evaporated by the high temperature atmosphere in the float bath but also sulfur introduced into the float bath with the molten glass. Volatilities are greatly increased by forming compounds with oxygen and invading oxygen from the outside. And because of the ventilation in the upper space of the float bath, in addition to the vapor of tin and the vapor of tin compound being discharged out of the float bath, a glass ribbon with a small amount of tin attached to the back surface Is taken out from the downstream end of the float bath, which causes a situation where the amount of tin stored in the float bath gradually decreases.

  Thus, tin is supplied into the float bath during the forming of the glass plate. As a conventional method of supplying tin, as shown in FIG. 5, the side wall of the float bath 20 is generally used. By removing the side sealing box built into the side wall 21 and thereby applying a pushing force in the direction indicated by the arrow b to the tin ingot 23 of 25 kg or more from the opening 22 formed in the side wall 6, the ingot 23 Was put into the molten tin 24 in the float bath 20.

  However, in such a simple method, it is inevitable that the opening 22 formed in the side wall 21 is much larger than the tin ingot 23, and the exposure time of the large opening 22 is unduly long. Therefore, a large amount of outside air (especially oxygen) enters the float bath 20 through the opening 22 to contaminate the molten tin 24, and the temperature of the molten tin 24 varies due to the heat of dissolution of the tin ingot 23. As a result, the glass ribbon was distorted, that is, the molding was hindered due to the deterioration of the surface irregularity.

  In order to cope with such a problem, according to Patent Document 1, a melting furnace for melting a metal (tin ingot) is provided outside the float bath, and tin melted in the melting furnace is provided in the float bath through a supply pipe. A float glass manufacturing apparatus configured to be supplied to is disclosed. According to this apparatus, since the periphery of the supply pipe from the melting furnace is sealed by the side sealing block, a large amount of oxygen invades into the float bath from a large opening as in the prior art, and the molten tin in the float bath. It can be expected to prevent the contamination.

JP-A-6-234533

  However, as disclosed in the above-mentioned Patent Document 1, according to the configuration in which the melting furnace is provided outside the float bath, the float glass apparatus becomes large and complicated due to the presence of the melting furnace, and the manufacturing cost and operation thereof are also increased. A fatal problem that costs will rise.

  Moreover, since it is necessary to let molten tin flow down into the float bath from the melting furnace through the supply pipe, the melting furnace has to be installed at a high position, making it difficult to install, as well as maintenance inspection of the melting furnace, etc. It also raises the problem that work becomes difficult.

  Furthermore, since this melting furnace has an opening for introducing a tin ingot into the furnace, the outside air enters the furnace through this opening and the molten tin in the furnace is contaminated. The contaminated molten tin may be supplied into the float bath.

  In view of the above circumstances, the present invention does not require a large and expensive facility, does not cause difficulty in work such as maintenance and inspection, and does not cause existing contamination of the metal as the input material. It is an object of the present invention to provide a float glass manufacturing apparatus capable of replenishing metal and a manufacturing method thereof.

The apparatus according to the present invention, which was created to solve the above technical problem, is continuously supplying molten glass from the upstream side to a bath surface of a float bath that stores molten metal, and forming a glass ribbon. In the float glass manufacturing apparatus configured to pull out the glass ribbon after molding from the downstream end of the float bath, the upper end opening of the internal passage is located outside the side wall of the float bath and The guide pipe in which the lower end opening of the internal passage is located inward of the side wall is installed in an inclined posture with its outer surface sealed, and the guide pipe has a metal ingot introduced into the internal passage from the upper end opening. It is structured to be guided to the lower end opening and dropped into the molten metal, and the upper end opening of the guide tube is covered with a lid member that suppresses intrusion of outside air into the inner side of the side wall so as to be opened and closed. Invitation Comprising a push rod to push the metal ingot resides within passageway of the tube to the lower end opening of the dielectric conduit, said push rod is configured so that the tip is capable of protruding from the lower end opening of the guide tube, the guide tube of the cross-sectional shape perpendicular to the guidance direction of the interior passage, characterized in that the cross-sectional shape and a phase similar shape perpendicular to the guidance direction of the metal ingot. Here, of the above two “guidance directions”, the former “guidance direction” means a direction in which the internal passage of the induction tube guides the metal ingot obliquely downward, and the latter “guidance direction”. "Means the direction in which the metal ingot is guided obliquely downward by the internal passage of the guide tube.

According to such a configuration, when replenishing metal into the float bath, by injecting the metal ingot into the internal passage of the guide pipe installed obliquely with the outer surface side sealed to the side wall of the float bath, The metal ingot is guided obliquely downward by the internal passage and is dropped into the molten metal in the float bath. Therefore, since the main components attached to the side wall of the float bath are related to the guide pipe having the internal passage for guiding the metal ingot and its peripheral structure, the added equipment can be simplified and maintained. Inspection work and the like can be easily performed. Moreover, since the cross-sectional shape orthogonal to the guide direction of the internal passage of the guide tube and the cross-sectional shape orthogonal to the guide direction of the metal ingot are similar, the area of the former cross-section is included in the area of the former cross-section. It is possible to make the gap between the two as small as possible while making the area of the two as close as possible. As a result, outside air enters the float bath from the gap between the inner passage of the guide pipe and the metal ingot using the advantageous technical idea that the metal ingot is put into the float bath. Problems such as contamination of the molten metal in the bus are suppressed as much as possible. Further, since the metal ingot can be guided to an appropriate position in the float bath by the guide tube, the impact when the metal ingot falls into the molten metal in the float bath can be reduced. The large ripples on the surface (bath surface) and the adverse effects on the glass ribbon due to this can be minimized. In addition, since the metal ingot is thrown in without being melted, there is no situation that the metal ingot is already contaminated before being thrown in, and the molten metal in the float bath is polluted by the characteristics of the metal ingot itself. The problem is reliably avoided. Further, since the upper end opening of the guide tube is covered with a lid member so as to be opened and closed, the entry of outside air into the inside of the side wall (inside the float bath) is also suppressed. Moreover, since the metal ingot thrown into the internal passage of the induction tube is surely pushed to the lower end opening by the push rod and then falls into the molten metal, the metal ingot is in front of the lower end opening of the induction tube. This avoids the problem of remaining and melt-adhering.

  In this case, when the area of the cross section orthogonal to the guide direction of the internal passage of the guide pipe is A and the area of the cross section orthogonal to the guide direction of the metal ingot is B, B / A is 0.7 or more. Preferably there is.

  In this way, the gap between the inner passage and the metal ingot is appropriately reduced until the metal ingot introduced into the inner passage from the upper end opening of the guide tube is guided to the lower end opening. Thus, the probability of occurrence of contamination of the molten metal due to the outside air entering the float bath through the gap is suitably reduced. That is, when the B / A is less than 0.7, the gap is excessively large, which may adversely affect the molten metal due to a large amount of outside air entering the float bath. If the above B / A is 0.7 or more, such influence can be ignored.

In addition to the above configuration, it is preferable that the guide tube is inclined to such an extent that the metal ingot cannot slide down the internal passage due to its own weight .

In this way, by the state of the metal ingot in the gentle slope of the induced conduit can not slide off the internal passage by its own weight, it is possible to induce reliably metal ingot to the lower end opening of the guide tube, the inclination of the guide tube Therefore, it is possible to effectively avoid problems such as the metal ingot sliding down at a high speed due to its own weight and causing undue undulations on the surface of the molten metal.

  In this configuration, it is preferable that the cross-sectional shape orthogonal to the guide direction of the internal passage of the guide pipe and the cross-sectional shape orthogonal to the guide direction of at least the tip of the push rod are similar.

  In this way, coupled with the fact that the cross-sectional shape of the internal passage of the guide pipe and the cross-sectional shape of the metal ingot are similar, it is possible to prevent further outside air from entering the float bath. it can. That is, even if the cross-sectional shape and the area of the metal ingot are the same as the cross-sectional shape and the area of at least the tip of the push rod, the postures of both, that is, the angles in the cross-section are different. In this case, since the area for closing the inner passage of the guide pipe is larger than that of either one, the gap between the guide passage and the inner passage of the guide pipe is inevitably reduced, and the outside air enters the float bath. Can be further prevented.

  Also in this case, when the area of the cross section orthogonal to the guide direction of the internal passage of the guide pipe is A and the area of the cross section orthogonal to the guide direction of at least the tip of the push rod is C, C / A Is preferably 0.7 or more.

  In this way, in addition to obtaining the numerical advantage by setting the above-mentioned B / A to be 0.7 or more, it is already possible to block the internal passage of the guide tube by the metal ingot and the push rod. The advantages described above can also be obtained appropriately.

  In addition to the above configuration, it is preferable that the guide pipe includes an outside air intrusion suppressing unit that suppresses intrusion of outside air into the inside of the side wall.

  In this way, in addition to optimizing the cross-sectional shape and cross-sectional area of the guide passage, the metal ingot, and the push rod, the guide pipe is provided with an outside air intrusion suppression means. This can be an effective measure for suppressing the intrusion of outside air from the guide tube into the float bath when no metal ingot is present in the internal passage.

In this case, the outside air intrusion inhibiting means may be a curtain of antioxidant gas formed so as to close the internal passage of the previous SL guide tube.

  Here, nitrogen gas or reducing gas can be used as the “antioxidant gas”. The “curtain” means a film-like gas shielding part formed in the internal passage by blowing an antioxidant gas.

  In the above configuration, the weight per metal ingot is preferably 5 kg or less.

  In this way, a commercially available metal ingot (a metal ingot conventionally used) is 25 kg, and if this is mixed as it is in the molten metal in the float bath, the surface of the molten metal In addition to the formation of unreasonably large waves, the temperature of the molten metal fluctuates due to the melting heat of the metal ingot, resulting in distortion of the glass ribbon. Therefore, if the metal ingot is subdivided and the cross section thereof is processed into the shape and area described above to make it 5 kg or less, and the metal ingot of 5 kg or less is used as the metal ingot, the occurrence probability of the distortion and the like is efficiently obtained. Can be reduced.

  Furthermore, in the above configuration, the guide pipe is preferably installed at a downstream position of the float bath.

  In this way, since the glass ribbon is solidified at the downstream position of the float bath as compared with the upstream position, even if the metal ingot is mixed into the molten metal at this position, the heat of dissolution Thus, the influence on the glass ribbon can be reduced, and the occurrence of the distortion and the like can be effectively suppressed.

On the other hand, the method according to the present invention, which was created in order to solve the above technical problem, forms a glass ribbon by continuously supplying molten glass from the upstream side to the bath surface of a float bath that stores molten metal. However, in the float glass manufacturing method having a glass ribbon forming step of drawing the glass ribbon after forming from the downstream end of the float bath, in the glass ribbon forming step, on the side wall of the float bath, on the outside of the side wall In the state where the upper end opening of the inner passage is located and the guide pipe in which the lower end opening of the inner passage is located inward of the side wall is sealed in the outer surface side and installed in an inclined posture, the upper end opening of the guide pipe from the time of dropping into the molten metal and guided to the lower end opening of the metal ingot is charged into the internal passage, the inside of the openable cover and the side wall of the upper end opening of the guide tube The addition to lid opening suppressing lid member penetration of outside air, and the cross-sectional shape perpendicular to the guidance direction of the internal passage of the guide tube, similar in shape and cross-sectional shape perpendicular to the guidance direction of the metal ingot, the tip It is characterized in that a metal ingot existing in the internal passage of the guide tube is pushed into the lower end opening of the guide tube by a push rod that can protrude from the lower end opening of the guide tube .

  According to such a method, it is possible to obtain substantially the same operational effects as those obtained with respect to the basic configuration of the float glass manufacturing apparatus described above.

As described above, according to the present invention, since the main components attached to the side wall of the float bath are related to the guide pipe having the internal passage for guiding the metal ingot and the peripheral structure thereof, the equipment to be added is simplified. The maintenance and inspection work can be easily performed. Moreover, since the cross-sectional shape orthogonal to the guide direction of the internal passage of the guide tube and the cross-sectional shape orthogonal to the guide direction of the metal ingot are similar, the area of the former cross-section is included in the area of the former cross-section. It is possible to make the gap between the two as small as possible, and the outside air enters the float bath from the gap between the guide tube and the metal ingot. Problems such as contamination of molten metal are suppressed as much as possible. Further, since the metal ingot is charged without being melted, the situation that the metal ingot is already contaminated before the charging does not occur, and the molten metal in the float bath is contaminated by the characteristics of the metal ingot itself. Defects are reliably avoided. In addition, since the upper end opening of the guide tube is covered with a lid member so as to be openable and closable, entry of outside air into the float bath is also suppressed by this. Moreover, since the metal ingot thrown into the internal passage of the induction tube is surely pushed to the lower end opening by the push rod and then falls into the molten metal, the metal ingot is in front of the lower end opening of the induction tube. This avoids the problem of remaining and melt-adhering.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following embodiments, a float glass manufacturing apparatus used for forming a glass substrate for FPD represented by PDP or LCD is exemplified.

  FIG. 1 is a schematic longitudinal sectional front view of a float glass manufacturing apparatus according to an embodiment of the present invention. As shown in the figure, the float glass manufacturing apparatus 1 according to this embodiment includes a float bath 3 in which molten tin 2 is stored at the bottom, and on the surface (bath surface) of the molten tin 2, the upstream side (of the paper surface). A glass ribbon 4 is formed by continuously supplying molten glass from the front side), and a drawing force from the downstream end (the back end of the paper surface) acts on the glass ribbon 4.

  The float bath 3 includes a plurality of bottom blocks 5a constituting the bottom wall 5 and a plurality of side blocks 6a and 7a constituting side walls 6 and 7 rising from both sides of the bottom wall 5 respectively. The upper space is covered with a plurality of roof blocks 8a constituting the ceiling wall 8, and casings 9 and 10 are pasted around the outer periphery of the blocks 5a, 6a, 7a and 8a. And the side sealing blocks 6b and 7b are respectively incorporated in the airtight state in the middle part in the up-and-down direction of the side walls 6 and 7, and the casing is not pasted on the outer peripheral side of these side sealing blocks 6b and 7b. An electric heater 11 for controlling the glass ribbon 4 to an appropriate temperature is arranged below the roof block 8 a constituting the ceiling wall 8.

  In the side sealing block 6b existing on the side wall 6 of one of the side walls 6 and 7 (the right side of the figure), the upper end opening 12a is located outside the side wall 6 and the lower end opening 12b is located inside the side wall 6. The guide tube 12 positioned immediately above the surface of the molten tin 2 is installed in an inclined posture with the outer surface side sealed. The guide tube 12 is configured to guide a metal ingot (tin ingot) 13 introduced from the upper end opening 12a into the internal passage 12c to the lower end opening 12b and drop it into the molten tin 2. The guide pipe 12 is disposed at a downstream position of the float bath 3.

  More specifically, as shown in FIG. 2, the guide tube 12 is a pipe member extending in a straight line, and the upper end opening 12a is covered with the lid member 14 so as to be opened and closed, and the lower end opening 12b is opened. Yes. A push rod 15 is inserted into the internal passage 12c of the guide tube 12 through the lid member 14 so as to be able to move forward and backward. The tip of the push rod 15 abuts on the tin ingot 13 and moves forward. Thus, the tin ingot 13 is configured to be pushed obliquely downward. As shown in FIG. 3, when the push rod 15 reaches the forward end, the tip of the push rod 15 slightly protrudes from the lower end opening 12b of the guide tube 12, and the tin ingot 13 is made of molten tin 2 It is supposed to fall inside.

  In this case, the push rod 15 is slidably inserted in a state where the shaft portion 15a is sealed in a through-hole formed at the center of the lid member 14, and an operator is attached to the rear end of the shaft portion 15a. A gripping portion 15b for gripping with a hand is mounted. In this embodiment, a contact portion 15c that contacts the tin ingot 13 is mounted at the tip of the shaft portion 15a. Further, in the vicinity of the upper end opening 12a in the internal passage 12c of the guide pipe 12, a film-like curtain 16 is formed by blowing out an antioxidant gas made of nitrogen gas or reducing gas.

  Thus, in this embodiment, the sectional shape orthogonal to the guiding direction a of the internal passage 12c of the guiding tube 12 and the sectional shape orthogonal to the guiding direction a of the tin ingot 13 are as shown in FIG. In addition, both are quadrangular and similar in shape. The area of the cross section of the tin ingot 13 is 70% or more of the area of the cross section of the internal passage 12c of the guide pipe 12. In this embodiment, the shape of the cross section perpendicular to the guide direction a of the contact portion 15c of the push rod 15 is also a quadrangle, and the area of the cross section is also the area of the cross section of the internal passage 12c of the guide pipe 12 70% or more.

  In this case, as long as the cross-sectional shape of the internal passage 12c of the guide tube 12 and the cross-sectional shape of the tin ingot 13 are similar, the triangle shown in FIG. 4B and the cross-sectional shape shown in FIG. It may be a circle or a polygon shown in FIG. 4 (d) (hexagon in the example), and the area ratio is the same as described above. The tin ingot 13 is obtained by subdividing a normal 25 kg tin ingot and processing it into a required shape to 5 kg or less.

  According to the float glass manufacturing apparatus 1 having the above configuration, tin is supplied to the molten tin 2 in the float bath 3 as described below. That is, first, immediately after opening the lid member 14 of the guide tube 12 shown in FIG. From the upper end opening 12a to the internal passage 12c. Thereby, as shown to Fig.4 (a), it will be in the state from which the slight clearance gap exists between the internal channel | path 12c of the induction | guidance | derivation pipe | tube 12, and the tin ingot 13. As shown in FIG. Therefore, at this time, it is difficult for outside air to enter the float bath 3 through the internal passage 12c of the guide tube 12. While this operation is performed, the internal passage 12c of the guide tube 12 is in a state of being blocked by the antioxidant gas curtain 16. As a result, a situation in which outside air enters the float bath 3 through the internal passage 12c of the guide tube 12 hardly occurs.

  Thereafter, the lid member 14 is closed to close the upper end opening 12a of the guide tube 12, and the push bar 15 is moved forward to push the tin ingot 13 diagonally downward of the internal passage 12c. As shown in FIG. 3, when the push rod 15 reaches the forward end, the tin ingot 13 falls into the molten tin 2 in the float bath 3.

  In this case, since the tin ingot 13 is configured to be guided obliquely downward through the internal passage 12c of the guide tube 12 by the push rod 15, the inclination of the guide tube 12 is so gentle that the tin ingot 13 cannot slide down due to its own weight. can do. Thereby, since the tin ingot 13 can be dropped after moving along the internal passage 12c of the guide tube 12 at a low speed, it is possible to reduce the ripple of the molten tin 2 immediately after the dropping. In addition, the guide pipe 12 is disposed at the downstream side position of the float bath 3, and since the glass ribbon 4 is appropriately solidified at the downstream side position, even if the tin ingot 13 is mixed into the molten tin 2, The influence of the heat of dissolution on the glass ribbon 4 is reduced as much as possible.

It is a vertical front view which shows schematic structure of the float glass manufacturing apparatus which concerns on embodiment of this invention. It is an expanded vertical front view which shows schematic structure of the principal part of the float glass manufacturing apparatus which concerns on embodiment of this invention. It is an expanded vertical front view which shows schematic structure of the principal part of the float glass manufacturing apparatus which concerns on embodiment of this invention. (A) is an expanded sectional view of the principal part of the float glass manufacturing apparatus which concerns on embodiment of this invention which concerns on embodiment of this invention, (b)-(d) is a cross section which shows the modification of the said principal part, respectively. FIG. It is an enlarged vertical front view which shows schematic structure of the principal part of the float glass manufacturing apparatus which concerns on a prior art example.

Explanation of symbols

1 Float glass manufacturing equipment 2 Molten tin (molten metal)
3 Float bath 4 Glass ribbon 12 Guide pipe 12a Upper end opening 12b Lower end opening 12c Internal passage 13 Tin ingot (metal ingot)
14 Lid member 15 Push bar 15 Contact part (tip part of push bar)
16 Antioxidant gas curtain

Claims (10)

The glass ribbon is drawn from the downstream end of the float bath while the molten glass is continuously supplied from the upstream side to the bath surface of the float bath containing the molten metal to form the glass ribbon. In the constructed float glass manufacturing device,
Inclined posture by sealing the outer surface side of the guide pipe in which the upper end opening of the internal passage is located outside the side wall and the lower end opening of the internal passage is located inside the side wall of the float bath The guide pipe is configured to guide the metal ingot introduced into the internal passage from the upper end opening to the lower end opening and drop it into the molten metal,
The upper end opening of the guide tube is covered with a lid member that suppresses intrusion of outside air into the inside of the side wall so as to be opened and closed,
A push bar that pushes a metal ingot existing in the internal passage of the guide pipe to the lower end opening of the guide pipe, and the push bar is configured so that the tip can protrude from the lower end opening of the guide pipe;
The induction pipe of the cross-sectional shape perpendicular to the guidance direction of the internal passage, a float glass manufacturing apparatus is characterized in that the cross-sectional shape and a phase similar shape perpendicular to the guidance direction of the metal ingot.   When the area of the cross section orthogonal to the guide direction of the internal passage of the guide pipe is A and the area of the cross section orthogonal to the guide direction of the metal ingot is B, B / A is 0.7 or more. The float glass manufacturing apparatus according to claim 1, wherein the apparatus is a float glass manufacturing apparatus. The float glass manufacturing apparatus according to claim 1 or 2, wherein the guide tube is inclined to such an extent that the metal ingot cannot slide down the internal passage by its own weight .   The float glass according to claim 3, wherein a cross-sectional shape orthogonal to the guide direction of the internal passage of the guide tube and a cross-sectional shape orthogonal to the guide direction of at least the tip of the push rod are similar. manufacturing device.   C / A is 0.7 or more, where A is a cross-sectional area perpendicular to the guiding direction of the internal passage of the guiding pipe and C is a cross-sectional area perpendicular to the guiding direction of at least the tip of the push rod. The float glass manufacturing apparatus according to claim 4, wherein   The float glass manufacturing apparatus according to any one of claims 1 to 5, wherein the guide tube includes an outside air intrusion suppressing unit that suppresses intrusion of outside air into the inside of the side wall.   The float glass manufacturing apparatus according to claim 6, wherein the outside air intrusion suppression means is an antioxidant gas curtain formed so as to close an internal passage of the guide pipe. The float glass manufacturing apparatus according to any one of claims 1 to 7 , wherein a weight per piece of the metal ingot is 5 kg or less. The induction pipe, a float glass manufacturing apparatus according to any one of claims 1-8, characterized in that it is installed at a position downstream of the float bath. Glass ribbon molding that continuously supplies molten glass from the upstream side to the bath surface of a float bath that stores molten metal to form the glass ribbon while drawing the glass ribbon from the downstream end of the float bath In the float glass manufacturing method having a step,
In the glass ribbon forming step, a guide pipe having an upper end opening of the internal passage located outside the side wall and a lower end opening of the internal passage located inside the side wall is provided on the outer surface of the float bath. When the metal ingot introduced into the internal passage from the upper end opening of the guide tube is guided to the lower end opening and dropped into the molten metal with the side sealed and installed in an inclined posture, A lid member that covers the upper end opening so as to be openable and closable and that suppresses intrusion of outside air into the inside of the side wall, and a cross-sectional shape that is orthogonal to the guiding direction of the internal passage of the guide pipe, and the metal ingot and a sectional shape perpendicular to the guidance direction and similar shapes, push the push rod to be projectable tip from the lower end opening of the guide tube, the metal ingot resides within passage of the guide tube to the lower end opening of the dielectric conduit Float glass production process, characterized in that writing.

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