JP2009221105A - Molten glass supply device and method of producing glass formed product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the quality of glass articles formed in each forming device and the product yield by properly improving a multi-feeder to supply molten glass to each forming device under a uniform condition. <P>SOLUTION: Each of distribution resistance providing portions 8, ... 8 is provided in the middle of each branch paths 4, ... 4 to give the distribution resistance to the molten glass flowing in each of the branch paths 4, ... 4 to equalize each supply pressure when the high viscosity molten glass is distributed and supplied to each of the branch paths 4, ... 4 from the distribution portion 3 in the multi-feeder 1 provided with a melting furnace 2, a distribution portion 3, and a plurality of branch paths 4. A plurality of baffle plates 9 are arranged in the distribution resistance providing portion 8 to change the direction of the flow of the high viscosity molten glass or to narrow flow. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a molten glass supply technique, and in particular, an improvement of a molten glass supply apparatus configured to supply molten glass flowing into a distribution unit from a melting furnace to each forming apparatus through a plurality of branch channels, and molten glass It is related with the improvement of the technique which supplies glass from a melting kiln and manufactures a glass molded article.

  In general, when a glass article is manufactured, a molten glass supply device including a melting furnace serving as a supply source of molten glass and a supply channel for supplying molten glass flowing out of the melting furnace to a molding apparatus is used. The As this molten glass supply apparatus, for example, as disclosed in the following Patent Documents 1 to 4, a distribution section that leads to the outlet of the melting furnace, and a branch from the distribution section that extends toward a plurality of molding apparatuses. An apparatus (hereinafter also referred to as a multi-feeder) having a plurality of branched flow paths is known.

  This multi-feeder melts glass (hereinafter also referred to as low-viscosity glass) that forms articles such as glass panels, glass funnels, window panes, and glassware of bottles and tableware, and articles equivalent thereto, such as cathode ray tubes (CRT). The molten glass is distributed and supplied from the melting furnace to each molding apparatus through the distribution section and each branch channel. That is, Patent Document 1 has a description of “window glass”, Patent Document 2 has a description of “glass gob” and “glass for container production”, and Patent Document 3 has a “glass bottle”. "And the composition of the glass that can be judged to be a low-viscosity glass are listed in Table 1, and since Patent Document 4 has a description of" glass bottles and glass tableware ", these are disclosed in each of these documents. It can be understood that the multi-feeder used is intended for the low-viscosity glass described above.

  On the other hand, in recent years, glass substrates for flat displays typified by liquid crystal displays (LCD) and electroluminescence displays (ELD), charge coupled devices (CCD), equal-magnification proximity solid-state imaging devices (CIS), CMOS image sensors, etc. The demand expansion of various image sensors and cover glasses such as laser diodes, and glass substrates for hard disks and filters has rapidly progressed.

  The articles listed below and the glass (hereinafter also referred to as high-viscosity glass) forming articles similar thereto have extremely different characteristics as compared with the low-viscosity glass described above. Specifically, taking a non-alkali glass for a liquid crystal display, which is a high-viscosity glass, and a soda-lime glass for containers, which is a typical example of a low-viscosity glass, as shown in FIG. The characteristic curve A shows that the viscosity does not decrease moderately unless it is an extremely high temperature region of about 1400 ° C. or higher, and the smooth flow of the molten glass in the molten glass supply device cannot be maintained. On the other hand, the characteristic curve B of soda-lime glass shows that the viscosity is moderately reduced at about 1200 ° C. or less. Strictly speaking, liquid crystal display glass (characteristic curve A) has a temperature of about 1460 ° C. or more and a viscosity of 1000 poise or less, while soda lime glass (characteristic curve B) has a temperature of about 1180 ° C. The viscosity is 1000 poises or less.

  The above-mentioned high viscosity glass generally exhibits a characteristic that when the viscosity is 1000 poise, the temperature corresponding to the viscosity is 1350 ° C. or higher, particularly 1420 ° C. or higher when the viscosity is high. The low-viscosity glass described above exhibits a characteristic that when the viscosity is 1000 poise, the temperature corresponding to the viscosity is 1250 ° C. or lower, particularly 1200 ° C. or lower when the viscosity is low. Therefore, the above-mentioned high viscosity glass and low viscosity glass can be distinguished based on the relationship between temperature and viscosity.

Japanese Patent Publication No. 48-17845 JP 62-176927 A JP-A-6-24752 JP 2000-313623 A JP 2000-185923 (FIG. 2)

  By the way, as disclosed in the above Patent Documents 1 to 4, in the multi-feeder for low viscosity glass, it is possible to easily reduce the viscosity of the molten glass. The molten glass that flowed in was supplied to each branch channel without any problem. For this reason, when molten glass is supplied from the distributor to each branch channel, the supply amount and viscosity vary between the branch channels, but the variation is not unreasonably large. Therefore, this variation has not been regarded as a problem.

However, if the multi-feeder disclosed in the above Patent Documents 1 to 4 is used to distribute and supply the high-viscosity glass as a molten glass to a plurality of molding apparatuses, the molten glass is reduced in viscosity. It is inevitable that it is extremely difficult to distribute and supply the branched flow path from the distribution section to each branch flow path with uniform viscosity. That is, when flowing this highly viscous glass as molten glass, it is necessary to maintain it at a very high temperature by heating means, but it is substantially impossible to heat the molten glass uniformly from all directions. As compared with the case of low viscosity glass, a large temperature difference is generated in the molten glass, and due to this, the viscosity becomes unreasonably uneven.

  Therefore, it becomes impossible to make the supply amount of the molten glass uniform for all the branch channels, and this causes the molten glass to be supplied from the distributor to each molding device through the branch channels under equal conditions. Is extremely difficult. More specifically, if the viscosity of the molten glass is relatively low at one location leading to one branch flow path in the distribution section, the molten glass immediately flows into the one branch flow path from the distribution section. If the viscosity of the molten glass is relatively high at other locations leading to other branch flow paths in the distribution section, the molten glass flows from the distribution section. It becomes difficult to flow into the other branch flow path, and the flowability of the molten glass toward the downstream side is hindered even after the flow.

  For this reason, there is a large variation in the amount of molten glass supplied to each molding device through each branch flow path, the molding process by each molding device cannot be performed under equal conditions, and the molding operation is hindered. This leads to problems such as a variation in quality, a decrease in quality, and a decrease in product yield. Due to the inevitable inconvenience of such a problem, conventionally, a multi-feeder is not used as an apparatus for supplying high-viscosity glass to a molding apparatus. As, for example, as disclosed in Patent Document 5 above, there is an apparatus (hereinafter also referred to as a single feeder) configured to supply molten glass from a melting furnace to a molding apparatus through a single supply channel. It was used.

  The present invention has been made in view of the above circumstances, and it is possible to supply molten glass under uniform conditions to each molding apparatus by appropriately modifying a manufacturing method involving distribution and supply of a multi-feeder and molten glass. In addition, an object of the present invention is to improve the quality of glass articles molded by each molding apparatus and improve the product yield.

  The present invention, which has been made to solve the above technical problem, includes a melting kiln serving as a molten glass supply source, a distribution unit communicating with the outlet of the melting kiln, and a plurality of molding apparatuses branched from the distribution unit. In the molten glass supply apparatus provided with a plurality of branch channels extending toward the top, the molten glass has a characteristic that a temperature corresponding to a viscosity of 1000 poise is 1350 ° C. or more, and each of the branches In the middle of the flow path, a flow resistance application portion is provided in which a plurality of baffle plates for providing flow resistance to the molten glass flowing through each branch flow path are fixed. In this case, it is preferable that each flow resistance imparting portion is disposed on the downstream side of the distribution portion in each branch flow path, that is, on the upstream end portion of each branch flow path. The distribution part preferably has a function as a volume part capable of temporarily stagnating the flow of the molten glass. However, the distribution part is merely a collection of the branch flow paths not having such a function. Part. Further, as the baffle plate, it is preferable that a plurality of baffle plates are arranged from the upstream side to the downstream side, and further, a plurality of baffle plates and / or different arrangement positions with respect to the cross section of the flow path of the molten glass. It is preferable that a plurality of baffle plates having different shapes are provided.

  According to such a configuration, the following advantages can be obtained. In other words, if no positive flow resistance is given to the molten glass flowing through each branch flow path, the low viscosity of the molten glass through the branch flow path from the distribution section with respect to the portion where the viscosity of the molten glass is relatively low. The part of the molten glass flows at a relatively high speed, whereas the part of the molten glass having a relatively high viscosity has a relatively low speed through the branch channel from the distributor. As a result, the supply pressure of the molten glass from the distributor to each branch channel becomes non-uniform. On the other hand, by imparting flow resistance to the molten glass flowing through each branch flow path, the flow velocity in the branch flow path can be increased for both the relatively low and high viscosity portions of the molten glass. If the speed is made extremely low, the flow speeds of both can be made substantially the same. In other words, the flow resistance necessary for making the flow speeds of both the above comparable may be provided in each branch flow path. Thereby, each supply pressure of the molten glass distributed and supplied from the distribution part to each branch flow path can be made uniform. As a result, it is possible to smoothly perform each molding operation without any trouble, and it is also possible to avoid problems such as variations in the quality of molded products, a decrease in quality, and a decrease in product yield. Moreover, each flow resistance imparting section can be configured by simply fixing a baffle plate in the middle of each branch flow path, preferably directly downstream of the distribution section, reducing labor and labor required for production. In addition, it is possible to reliably impart flow resistance to the molten glass. In addition, the baffle plate can change the flow direction of the molten glass or constrict the flow, which facilitates heat transfer between the parts with different viscosities in the molten glass, and individual flow resistance There is an advantage that it can contribute to the rectification of the molten glass in the application portion, and to the homogenization of the viscosity. Therefore, the flow resistance imparting portion also serves as a viscosity uniformizing portion for the molten glass.

  The above operation and effect become remarkable when the glass to be supplied is a highly viscous glass. Therefore, molten glass having a characteristic that the temperature corresponding to a viscosity of 1000 poise is 1350 ° C. or higher (further having a characteristic that the temperature corresponding to a viscosity of 1000 poise is 1420 ° C. or higher) is supplied. It becomes. This glass is a high-viscosity glass, as is clear from the matters already described, and is distinguished from a low-viscosity glass. And this highly viscous glass contains an alkali free glass (glass whose alkali component is 0.1% or less, especially 0.05% or less).

  As described above, since the molten glass supply device for high-viscosity glass has a structure in which a plurality of branch flow paths extend from the melting furnace via the distribution unit, this type of high-viscosity glass is targeted. Compared to the conventional molten glass supply device (single feeder), problems due to excessive heat dissipation and excessive erosion in the melting furnace are avoided. That is, the value obtained by dividing the heat dissipation area of the melting kiln when the multi-feeder is used by the number of branch channels, that is, the heat dissipation area of the melting kiln per branch channel is the volume of the melting kiln and the total volume. This is much smaller than the heat radiation area of the melting kiln per supply channel in a plurality of single feeders having the same melting kiln. As described above, since the heat radiation area of the melting furnace per one branch flow path is much smaller than that of the conventional apparatus (single feeder), the heat radiation amount from the melting furnace for one branch flow path is small. It is possible to avoid an excessive increase in the heating cost necessary for one molding line and to reduce the product cost. In addition, the value obtained by dividing the contact area with the molten glass on the inner wall of the melting furnace by the number of branch channels, that is, the erosion area of the melting furnace per branch channel is also the supply channel in the case of a single feeder. Much smaller than the erosion area of the melting furnace per one. As a result, the amount of erosion foreign matter in the molten glass supplied to the molding apparatus through individual branch channels and the amount of foreign glass due to erosion are not excessive, and contamination of the molten glass and the quality of the molded product resulting from this The problem of decline and product yield is avoided.

  In addition, if a high-viscosity glass is to be supplied to each forming apparatus as a molten glass using a multi-feeder, as is apparent from the characteristics shown in FIG. 5, the temperature of the molten glass has changed slightly. However, since the viscosity changes greatly, it is extremely difficult to maintain the viscosity uniform. Particularly, when the molten glass is distributed and supplied from the distribution unit to the plurality of branch channels, the viscosity is May be unjustly uneven. However, this problem can be avoided by the configuration according to the present invention as described above. Therefore, even if it is a case where high viscosity glass is made into a supply object, the various advantages which a multi feeder has can be enjoyed.

  That is, the advantage that different types of glass articles can be simultaneously formed by the molten glass distributed and supplied from the same melting furnace is obtained. Moreover, even when the supply of the molten glass from one branch channel is stopped, the required molding process can be performed by supplying the molten glass to the molding apparatus through another branch channel. Therefore, when it is desired to change the molding of a glass article by one line molding apparatus to the molding of another different glass article, it is not necessary to stop all of the branch flow paths, and the branch corresponding to the line to be changed. Only the flow path is stopped, the molding apparatus is replaced and replaced, and the other molding apparatuses can be kept in an operating state, so that the production efficiency can be improved.

In addition, each branch flow path in this multi-feeder may extend radially from the distribution unit toward each molding device, or may extend from the distribution unit toward each molding device in parallel with each other. However, in order to prevent problems such as non-uniform viscosity of molten glass and deterioration of fluidity, it is preferable that all of these branch flow paths extend linearly in plan view. Moreover, in the melting furnace, foreign substances such as silica may be in a state of floating in the form of a film on the liquid surface of the molten glass. In such a case, the purpose of removing the film-like suspended matter, etc. Therefore, it is preferable that two or three or more melting furnaces are installed in series from the upstream side to the downstream side.

  In particular, in recent years, with the widespread use of liquid crystal display devices and the increase in size of the panels, the demand for plate glass constituting the liquid crystal display devices has increased rapidly, and the size of the panels has increased. In this case, a slight difference in composition or material property between the two glass plates sandwiching the liquid crystal tends to cause a pitch shift at the time of manufacturing the panel. Therefore, a large amount of glass having a constant composition and material properties is required, and for such an increase in demand for plate glass, a conventional molten glass supply device (single feeder) may be added. According to such a simple method, plate glass produced by different single feeders has different operating conditions and blending conditions, so that the composition and material characteristics are not constant even for the same type. Invite. On the other hand, the molten glass supply apparatus according to the present invention is formed by branching a plurality of supply channels (branch channels) from the melting kiln, so that it can easily cope with the recent increase in demand for plate glass. In addition, even glass plates formed through different branch channels have the same operating conditions and blending conditions, and the composition and material properties are constant accordingly. As a result, it becomes possible to supply a large amount of plate glass having a constant composition and material properties.

  In such a configuration, it is preferable that each supply pressure when the molten glass is distributed and supplied from the distribution unit to each branch channel is made uniform.

Here, the uniform supply pressure means that there is no undue variation in the amount of molten glass that is distributed and supplied to each branch flow path, and the molten glass remains in each branch flow path even after distribution and supply. Means flowing with equal fluidity. Therefore, the molten glass continuously flowing from the melting furnace into the distribution unit is appropriately supplied to each molding apparatus without causing a large difference in quantity through each branch flow path, and the molding process by each molding apparatus is performed as follows: Performed on equal conditions with appropriate certainty. As a result, the smoothing of each molding operation is sufficiently promoted, and problems such as variations in the quality of molded products, a decrease in quality, and a decrease in product yield can be avoided appropriately.

  In such a configuration, at least the contact surface with the molten glass on the inner wall surface of the flow resistance imparting portion is preferably formed of platinum, molybdenum, palladium, rhodium, or an alloy thereof (hereinafter referred to as platinum). More preferably, platinum or a platinum alloy is used.

  If it does in this way, when supplying highly viscous glass as molten glass, the distribution resistance provision part which has sufficient durability can be obtained. That is, platinum and the like have excellent heat resistance and erosion resistance, so even when they come into contact with extremely high-temperature molten glass made of high-viscosity glass, they are unlikely to undergo thermal deformation or erosion, and therefore can withstand long-term use. An obtained distribution resistance imparting portion is obtained. This avoids a situation where the inner wall surface of the flow resistance imparting portion is eroded by contact with the molten glass made of highly viscous glass and foreign matter is generated, and molding by mixing or melting of the eroded foreign matter into the molten glass is avoided. Problems such as product quality degradation and product yield decline do not occur. In this case, all the wall portions of the corresponding portion of the distribution resistance application portion may be formed of platinum or the like, but considering that this platinum or the like is expensive, the main body of the distribution resistance application portion is made of a refractory (refractory brick). Etc.) and at least the contact surface of the inner wall surface with the molten glass is preferably covered with a thin plate such as platinum. In addition, if platinum or the like having both heat resistance and corrosion resistance of 1350 ° C. or higher (preferably 1420 ° C. or higher) is used, both heat treatment and erosion resistance can be realized at the same time. It is possible to reduce the time and effort.

  Furthermore, it is preferable to include an electric heating means for heating the molten glass by energizing the platinum or the like.

  In this way, if the molten glass in the flow resistance application portion is heated by energizing the above-described platinum or the like using the electric heating means, the molten glass is in the flow resistance application portion. It will be heated through a contact part with this molten glass, and compared with the case where it heats using a burner, while heating efficiency improves, it becomes possible to heat a molten glass uniformly. Further, in the case where such energization heating is performed, even when heating by a burner is used in combination, the molten glass can be efficiently and uniformly heated as compared with the case where heating is performed only by the burner.

  In this case, if a temperature detecting means for detecting the temperature of the molten glass in each flow resistance applying portion is provided, and the amount of current supplied to the above-described platinum or the like is variably controlled based on a signal from the temperature detecting means. In addition, it becomes possible to maintain the temperature of the molten glass in each flow resistance applying portion at an optimum value. Therefore, this distribution resistance imparting part also serves as a temperature adjusting part for controlling the temperature of the molten glass.

  Further, not only each flow resistance imparting part but also at least the contact surface with the molten glass on the inner wall surface of the above-mentioned distribution part, heat treatment and erosion treatment at 1350 ° C. or higher (preferably 1420 ° C. or higher), such as platinum It is preferable to perform a process of covering with a thin plate. Note that the same treatment can be applied to the melting furnace formed of the refractory, but since the volume of the melting furnace is much larger than that of the distribution section and the distribution resistance imparting section, It is advantageous in terms of cost that the treatment is not performed, and the problem of eroding foreign matters when high viscosity glass is targeted can be avoided by other means as described in the following embodiment. Preferably not.

  Further, among the three of the flow resistance imparting unit, the distributing unit, and the melting furnace, the distributing unit has the highest temperature (in the case of high-viscosity glass, for example, 1600 ° C. to 1700 ° C., and the viscosity is 1000 poise or less). It is preferable to heat so that. That is, since a complicated and complicated flow is generated in the molten glass in the distribution section, it is convenient to keep the viscosity low in order to distribute and supply the molten glass uniformly to each branch channel. is there.

  In such a configuration, it is preferable that at least a contact surface of the baffle plate with the molten glass is formed of platinum or the like. In this case, the heat-resistant treatment and the erosion-resistant treatment may be performed separately, but platinum having both heat resistance of 1350 ° C. or higher (preferably 1420 ° C. or higher) and erosion resistance, particularly platinum or platinum. It is preferable to use an alloy. Also, the baffle plate body may be formed of other heat-resistant members, and the contact surface with the molten glass may be covered with a thin plate such as platinum, but this baffle plate requires a large rigidity and a wide area. Therefore, it is preferable that the baffle plate itself is made of a plate such as platinum.

  Even in this case, the durability of the baffle plate against the heat of the molten glass is improved and it can withstand long-term use, and in particular, erosion foreign matter is caused by contact between the molten glass made of high-viscosity glass and the baffle plate. Occurrence of such a situation is avoided, and problems such as deterioration of the quality of molded products and product yield due to the penetration of eroded foreign substances into the molten glass do not occur.

  In the above configuration, the molding apparatus is preferably a sheet glass molding apparatus.

  And the glass molded product containing plate glass becomes a quality thing excellent in the quality by shape | molding and manufacturing the molten glass supplied from the molten glass supply apparatus provided with the above structure with the said shaping | molding apparatus.

  In this case, examples of the sheet glass forming apparatus include a down draw forming apparatus, an up draw forming apparatus, and a float forming apparatus, and further examples of the down draw forming apparatus include an overflow forming apparatus and a slot down forming apparatus. . Among these, it is desirable to use an overflow molding apparatus that does not require polishing of the surface of the molded sheet glass. Further, as the plate glass formed by these forming apparatuses, various image sensors such as a glass substrate of a flat display typified by a liquid crystal display or an electroluminescence display, a charge coupled device, an equal magnification proximity solid-state imaging device, a CMOS image sensor, etc. And a glass substrate of a hard disk or a filter.

  In forming these plate glasses, if the viscosity of the molten glass supplied to the forming apparatus is not uniform, the thickness of the plate glass varies and undulates, resulting in forming defects and a reduction in product yield. These problems are particularly fatal in applications such as glass substrates for liquid crystal displays that require high quality. And since this invention can respond appropriately to the problem of viscosity nonuniformity as already stated, it will be suitable for shaping | molding of the above-mentioned plate glass.

  In addition, the method for producing a glass molded article according to the present invention, which has been made to solve the above technical problem, is a melting method in which a glass having a characteristic that a temperature corresponding to a viscosity of 1000 poise is 1350 ° C. or more is melted in a melting furnace. A process, a distribution step of supplying the molten glass that has flowed out of the melting furnace to a plurality of branch channels via a distribution unit that leads to an outlet of the melting furnace, and a branching of the molten glass that flows through the plurality of branch channels A flow resistance imparting step for imparting flow resistance by passing a plurality of baffle plates fixed in the flow path, and a molding for passing the molten glass flowing down the plurality of branch flow paths to the plurality of branch flow paths, respectively. And a molding step of molding the glass molded article by supplying the apparatus.

  Also by implementing this manufacturing method, the basic effects of the molten glass supply apparatus already described can be obtained. In carrying out this manufacturing method, it is preferable that the molten glass is in contact with platinum or the like in the flow resistance application step in order to obtain the same effects as those already described. It is preferable that a heat treatment and an erosion treatment of at least ° C. are performed, it is preferable to heat the molten glass by energizing the platinum or the like, and at least the contact surface of the baffle plate with the molten glass Preferably, the forming step is a step of forming plate glass (particularly a glass substrate of a flat display).

  As described above, according to the molten glass supply apparatus according to the present invention (the manufacturing method of the glass molded product is substantially the same), each of the multi-feeders including the melting furnace, the distribution unit, and the plurality of branch channels is provided. Since flow resistance imparting sections that provide flow resistance to the molten glass flowing through the branch flow path are provided, the flow velocity in the branch flow path for both the relatively low and high viscosity portions of the molten glass By extremely reducing the speed, each supply pressure of the molten glass distributed and supplied from the distribution unit to each branch flow path can be made uniform, and each molding operation can be performed smoothly without any trouble. It is possible to avoid problems such as variations in the quality of the molded product, a decrease in quality, and a decrease in product yield. In addition, since a plurality of branch channels are formed by branching from the melting furnace, it is possible to easily cope with an increase in demand for plate glass in recent years without adding another molten glass supply device, and different branch channels. Even in the case of the plate glass formed through the process, since the operation conditions and the blending conditions are the same, a large amount of plate glass having a constant composition and material properties can be supplied.

  In addition, since each flow resistance applying portion is configured by fixing a baffle plate in the middle of each branch flow path, the flow resistance is applied to the molten glass after reducing labor and labor required for production. Can be reliably performed. In addition, the baffle plate can change the flow direction of the molten glass or restrict the flow of the molten glass, so that heat transfer between the parts of the molten glass having different viscosities is promoted, and individual branch flows The advantage that it can contribute effectively to the homogenization of the viscosity of the molten glass in the channel is obtained.

  Furthermore, since a high-viscosity glass having a temperature corresponding to a viscosity of 1000 poise of 1350 ° C. or higher (more preferably 1420 ° C. or higher) is an object to be supplied, compared with a single feeder which is a conventional apparatus, The heat radiation area of the melting kiln per branch flow path is much smaller, and it becomes possible to reduce the heating cost required for each molding line and to reduce the product cost. In addition, the erosion area of the melting furnace per branch flow path is much smaller than that of the conventional apparatus (single feeder), and in the molten glass supplied to the forming apparatus through each branch flow path By reducing the amount of eroded foreign matter and the amount of foreign glass, it is possible to avoid problems such as contamination of the molten glass and deterioration of the quality of molded products and product yield due to this.

It is a partially broken schematic perspective view which shows the whole structure of the molten glass supply apparatus which concerns on embodiment of this invention. It is a cross-sectional top view which shows the principal part of the molten glass supply apparatus which concerns on embodiment of this invention. It is a vertical side view which shows the principal part of the molten glass supply apparatus which concerns on embodiment of this invention. 4 (a) to 4 (e) are respectively longitudinal sectional front views showing baffle plates installed in a branch flow path that is a component of the molten glass supply apparatus according to the embodiment of the present invention. It is the graph which compared the characteristic of the high viscosity glass with which this invention is applied, and the characteristic of the low viscosity glass which concerns on a prior art.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially broken perspective view showing a schematic configuration of a molten glass supply apparatus according to an embodiment of the present invention, FIG. 2 is a transverse plan view showing a main part of the molten glass supply apparatus, and FIG. It is a vertical side view which shows the principal part of a glass supply apparatus. In the following description, the direction between the upstream side and the downstream side of the molten glass supply apparatus is also referred to as the front-rear direction, and the direction orthogonal to the front-rear direction in the horizontal plane is also referred to as the left-right direction.

First, based on FIG.1 and FIG.2, the whole structure of the molten glass supply apparatus which concerns on embodiment of this invention is demonstrated. The molten glass supply apparatus 1 includes a substantially rectangular melting furnace 2 serving as a molten glass supply source, a distribution chamber (distribution unit) 3 communicated with an outlet 2 a of the melting furnace 2, and the distribution chamber 3. A plurality of branch flow paths 4 communicated at substantially equal intervals to the downstream end of each of the flow paths, and the downstream ends of these branch flow paths 4 communicate with a plurality of molding devices 5, respectively. Note that the number of paths through the branch flow path 4 to the molding apparatus 5 is three in the illustrated example, but may be two, or may be four or more. Moreover, the melting kiln 2 may be arranged in a state where two or more are connected in series or in parallel from the upstream side to the downstream side, for example.

  The melting furnace 2 has a bottom wall 21, side walls 22 to 25, and an arched ceiling wall 26 that covers the entire area above the bottom wall 21, and each of these walls is formed of a high zirconia refractory (refractory brick). At the same time, flames F of a plurality of burners are irradiated from above the left and right side walls 22 and 23 toward the upper space of the molten glass. And the flame F of these burners is maintaining the temperature of 1500-1650 degreeC by heating the molten glass with which the inside of the melting furnace 2 is filled from upper direction.

  The downstream side wall 24 of the melting furnace 2 has an outlet 2a formed at the center in the left-right direction. The outlet 24a is connected to the melting furnace 2 via a narrow outlet 6 having the outlet 2a at the upstream end. The distribution chamber 3 is in communication. The distribution chamber 3 has a bottom wall 31, side walls 32 to 35, and an arched ceiling wall (not shown) that covers the entire area above the bottom wall 31, and each of these walls has a high zirconia refractory (refractory brick). ). The outflow passage 6 has passage walls 61 to 63 and an arched ceiling wall (not shown) covering the entire upper area thereof, and these walls are also made of high zirconia refractories (refractory bricks). Is formed. And from the upper side of the left and right side walls 32 and 33 of the distribution chamber 3, the flame F of the burner is irradiated toward the upper space of the molten glass filled inside. In this case, the temperature of the molten glass in the distribution chamber 3 is maintained at 1600 ° C to 1700 ° C.

  The distribution chamber 3 is smaller in volume than the melting furnace 2, and a thin plate made of platinum or a platinum alloy is stretched on the inner wall surface (at least the inner wall surface portion in contact with the molten glass) of the bottom wall 31 and the side walls 32 to 35. In addition, a thin plate made of platinum or a platinum alloy is similarly stretched on the bottom wall 61 of the outflow passage 6 and the inner wall surfaces of the side walls 62 and 63. The distribution chamber 3 is elongated in the left-right direction, and the downstream end of the outflow passage 6 is opened at the center in the left-right direction of the upstream side wall 34. And in the center part of the distribution chamber 3 in the front-rear and left-right direction, a straightening wall part 37 that is long in the left-right direction is fixed with a flow space between all the side walls 32 to 35. The rectifying wall portion 37 is also formed of a high zirconia refractory (refractory brick), and a thin plate made of platinum or a platinum alloy is stretched on the outer surface thereof.

  In this case, as shown in FIG. 3, the distribution chamber 3 is shallower than the melting furnace 2. That is, the depth dimension X to the bottom surface 21a of the melting furnace 2 is longer than the depth dimension Y to the bottom surface 31a of the distribution chamber 3 on the basis of the liquid level L of the molten glass when the apparatus 1 is in operation. Has been. Specifically, the depth dimension Y of the distribution chamber 3 is 4/5 or less, preferably 3/5 or less, more preferably 1/2 or less of the depth dimension X of the melting furnace 2, and 1 / 20 or more. The depth dimension Y of the distribution chamber 3 is 500 mm or less, preferably 400 mm or less, and 50 mm or more. In this embodiment, the outflow path 6 has the same depth as the distribution chamber 3, and a step D is formed at the boundary between the melting furnace 2 and the outflow path 6.

  As shown in FIGS. 1 and 2, a plurality of small outlets 3a are formed at substantially equal intervals on the downstream side wall 35 of the distribution chamber 3, and each of these small outlets 3a is connected to the upstream end. A plurality of branch passages 4 communicate with the downstream side of the distribution chamber 3 through the narrow small outflow passages 7. The plurality of branch channels 4 are arranged in parallel to each other, and all of the individual branch channels 4 extend on a straight line in plan view.

  A plurality of flow resistance imparting chambers (flow resistance imparting portions) 8 that open at the downstream ends of the small outflow passages 7 are formed at the upstream end of each branch flow path 4, that is, at a position immediately downstream of the distribution chamber 3. Has been. These flow resistance imparting chambers 8 are long in the front-rear direction and have a smaller volume than the distribution chamber 3. And each distribution | circulation resistance provision chamber 8 has the surrounding walls 81-85 which form a flow path, and the ceiling wall (illustration omitted) which covers the whole upper area, These each wall is a high zirconia refractory ( Refractory brick). The small outflow passage 7 has passage walls 71 to 73 and a ceiling wall (not shown) covering the entire area above the passage walls 71 to 73, and these walls are also formed of a high zirconia refractory (refractory brick). ing. Each distribution resistance imparting chamber 8 is shallower than the distribution chamber 3.

  Further, a thin plate made of platinum or a platinum alloy is stretched on the inner wall surface (at least the inner wall surface portion in contact with the molten glass) of the surrounding walls 81 to 85 of each flow resistance imparting chamber 8, and the passage of the small outflow passage 7 Similarly, thin plates made of platinum or a platinum alloy are stretched on the inner wall surfaces of the walls 71 to 73. Then, the molten glass in the flow resistance imparting chamber 8 is energized and heated by flowing an electric current through the above-described thin plate made of platinum or platinum alloy by an energizing heating means (not shown). Further, in each flow resistance imparting chamber 8, temperature detection means (temperature sensor) (not shown) for detecting the temperature and viscosity of the molten glass is disposed. Based on signals from these temperature detection means. Thus, the energization amount when performing the above-described energization heating, and thus the heating amount is controlled. Accordingly, each flow resistance imparting chamber 8 also serves as a temperature adjustment chamber (temperature adjustment unit). And by performing such control, the temperature of the molten glass in each flow resistance provision chamber 8 is maintained at 1500 to 1650 degreeC.

  In each of the flow resistance imparting chambers 8, baffle plates 9 made of a plurality of platinum or platinum alloys for constricting the flow while changing the flow direction of the molten glass flowing through the chamber are provided at predetermined intervals in the front-rear direction. Are fixed in parallel. And as a result, these baffle plates 9 provide resistance to the molten glass flowing through each flow resistance applying chamber 8, in other words, any of the low-viscosity part and the high-viscosity part of the molten glass. Is prevented from flowing immediately without receiving resistance at the upstream end of each branch flow path 4. Therefore, these baffle plates 9 and thus each flow resistance imparting chamber 8 constitutes a distribution pressure adjusting means for making the supply pressure uniform when the molten glass is distributed and supplied from the distribution chamber 3 to each branch flow path 4. It is.

  FIGS. 4A to 4E are front views showing baffle plates 9 arranged in order from the upstream side in each flow resistance applying chamber 8. In addition, the chain line L described in each figure shows the liquid level of the molten glass at the time of this apparatus 1 operation | movement.

The baffle plate 9 at the most upstream position shown in FIG. 4 (a) has a rectangular shape covering a cross section corresponding to a substantially lower half of a rectangular flow path cross section in the flow resistance applying chamber 8, and is melted. The glass flow is lowered after the direction is changed upward. The second baffle plate 9 from the upstream side shown in FIG. 4 (b) has a rectangular shape covering a cross section corresponding to a substantially upper half or a substantially upper third of the flow path cross section of the flow resistance imparting chamber 8. Then, the flow of the molten glass is raised after being squeezed while changing the direction downward. The third baffle plate 9 from the upstream side shown in FIG. 4 (c) has a rectangular shape that covers the center portion excluding both sides in the width direction of the flow path cross section of the flow resistance imparting chamber 8 from the top to the bottom. Thus, the molten glass flow is collected after being separated on both sides in the width direction. The fourth baffle plate 9 from the upstream side shown in FIG. 4 (d) is a plate-like body that covers the entire surface of the flow passage cross section of the flow resistance imparting chamber 8, and a plurality of through holes 9a having a relatively larger diameter on the upper side. In which the flow of molten glass is gathered after being narrowed down at a plurality of locations with a vertical difference. The fifth baffle plate 9 from the upstream side shown in FIG. 4 (e) is a plate-like body that covers the entire surface of the flow path cross section of the flow resistance imparting chamber 8, and a plurality of through holes having a relatively large diameter on the lower side. 9a is formed, and the molten glass flows are gathered after being narrowed down at a plurality of locations with a vertical difference. As described above, the direction of the flow of the molten glass is changed or squeezed to actively transfer heat between the low viscosity portion and the high viscosity portion, thereby improving the heat transfer efficiency. The plate 9 can also perform the rectifying action of the molten glass in the individual flow resistance imparting chambers 8, and thus the viscosity equalizing action. Accordingly, each flow resistance imparting chamber 8 also serves as a viscosity homogenizing chamber (viscosity uniformizing portion).

  The molten glass supplied from the melting furnace 2 shown in FIG. 1 and FIG. 2 to each molding device 5 through the distribution chamber 3 and each flow resistance imparting chamber 8 has a temperature corresponding to a viscosity of 1000 poise of 1350 ° C. or higher. Has a characteristic of 1420 ° C. or higher, and is preferably alkali-free glass. The strain point of the glass is 600 ° C. or higher, preferably 630 ° C. or higher, and the liquid phase viscosity of the glass is 300000 poise or higher, preferably 600000 poise or higher. And the composition of glass is as follows, when it shows by the mass%, for example.

_{SiO 2: 40~70%, Al 2} O 3: 6~25%, B 2 O 3: 5~20%, MgO: 0~10%, CaO: 0~15%, BaO: 0~30%, SrO : 0 to 10%, ZnO: 0 to 10%, alkali metal oxide: 0.1% or less, clarifier: 0 to 5%. In this case, the glass composition is preferably as follows. _{SiO 2: 55~70%, Al 2} O 3: 10~20%, B 2 O 3: 5~15%, MgO: 0~5%, CaO: 0~10%, BaO: 0~15%, SrO : 0 to 10%, ZnO: 0 to 5%, alkali metal oxide: 0.1% or less, clarifier: 0 to 3%.

  In addition, each molding apparatus 5 to which molten glass is supplied from each flow resistance applying chamber 8 through the downstream branch flow path 10 is a plate glass molding apparatus represented by a liquid crystal plate glass (glass substrate for liquid crystal display). It is.

  In addition, although each wall of the above-mentioned predetermined component is all formed with a high zirconia refractory, each wall of the component other than the melting furnace 2 is formed with a refractory other than the high zirconia. Also good.

  According to the molten glass supply apparatus 1 having the above configuration, the plurality of branch flow paths 4 extend from the melting furnace 2 through the distribution chamber 3 toward the molding apparatus 5 side. The molten glass exhibiting high viscosity characteristics in 2 is supplied to each molding device 5 through each of the branch flow paths 4. That is, a melting step of melting high-viscosity glass having a characteristic corresponding to a viscosity of 1000 poise of 1350 ° C. or more in the melting furnace 2, and the molten glass flowing out of the melting furnace 2 is discharged from the outlet 2 a of the melting furnace 2. A distribution step of supplying the plurality of branch flow paths 4 via the distribution chamber 3 leading to the flow path, a flow resistance applying step for applying a flow resistance to the molten glass flowing through the plurality of branch flow paths 4, and a plurality of branch flows The molten glass that has flowed down the passage 4 is supplied to the forming devices 5 that respectively lead to the plurality of branch passages 4 to form a glass molded product.

  Therefore, the value obtained by dividing the heat radiation area of the melting furnace 2 (particularly the heat radiation area of the side walls 22 to 25) by the number of the branch flow paths 4, that is, the heat radiation area of the melting furnace 2 per branch flow path 4 is The supply flow path of a plurality of single feeders having a plurality of melting kilns whose total volume is the same as the volume of the melting kiln 2 is much smaller than the heat dissipation area of one melting kiln. As a result, the amount of heat released from the melting kiln 2 for each branch channel 4 is not excessive, and an undue increase in heating cost required for one molding line can be avoided. In addition, the value obtained by dividing the contact area with the molten glass on the inner wall surface of the melting furnace 2 by the number of the branch channels 4, that is, the erosion area of the melting furnace 2 per one branch channel 4 is also a single feeder. This is much smaller than the erosion area of the melting kiln per supply channel. As a result, the amount of erosion foreign matter in the molten glass supplied to the molding apparatus 5 through the individual branch flow paths and the amount of foreign glass due to erosion are not excessive, and the molten glass is contaminated and the quality of the molded product is deteriorated due to this. And the problem of reduced product yield is avoided.

  Furthermore, if a plurality of molding devices 5 are different, different types of plate glass can be simultaneously molded by the plurality of molding devices 5 by the molten glass distributed and supplied from the same melting furnace 2. Moreover, even if the supply of the molten glass from one branch flow path 4 is stopped, the molten glass can be supplied to the molding apparatus 5 through the other branch flow path 4 to perform a required forming process. When it is desired to change the forming of the sheet glass by the forming device 5 of one line to the forming of another different plate glass, only the branch flow path 4 corresponding to the line to be changed is stopped and the forming device is replaced and replaced. The other molding apparatus 5 can be in an operating state. In addition, in a high viscosity glass such as glass for liquid crystal, the molding temperature becomes high, and the molding apparatus and the like are easily damaged, but even if one of the branch flow paths 4 is in a supply stop state for repair, Other molding apparatuses can be kept in operation.

  Moreover, since the branch flow path 4 is formed by branching into a plurality from the melting furnace 2, it can easily cope with the recent increase in demand for plate glass without adding another molten glass supply device, and is different. Even plate glass formed through the branch channel 4 has the same operating conditions and blending conditions, so that a large amount of plate glass having a constant composition and material properties can be supplied.

  In addition to the natural phenomenon due to the relationship between specific gravity and temperature, the molten glass that is about to flow out from the melting furnace 2 into the distribution chamber 3 is irradiated with the burner frame F in its upper space. However, since the distribution chamber 3 is shallower than the melting furnace 2, the lower viscosity molten glass remains in the melting furnace 2. Only the molten glass with low viscosity at the top flows into the distribution chamber 3. As a result, the molten glass having a low viscosity can be effectively used without waste, the viscosity of the molten glass can be made uniform from the upper part to the lower part of the distribution chamber 3, and defoaming from the molten glass is further promoted. Is done.

  Moreover, since zirconia, which is a component of a refractory eroded by the molten glass coming into contact with the melting furnace 2, has a higher specific gravity than the molten glass, a contaminated molten glass in which the zirconia is dissolved in the molten glass is Accumulate at the bottom. Even in such a case, since the distribution chamber 3 is shallower than the melting furnace 2, the contaminated molten glass is appropriately prevented from flowing into the distribution chamber 3.

  The molten glass that has flowed into the distribution chamber 3 is irradiated with the burner frame F by oxyfuel combustion and heated so that its viscosity is 1000 poise or less. 3, the molten glass can be smoothly distributed and supplied to the flow resistance imparting chamber 8 of each branch flow path 4. The molten glass that has flowed into the distribution chamber 3 from the melting furnace 2 is prevented from going straight by the rectifying wall portion 37 disposed in the center of the distribution chamber 3, and the flow is appropriately dispersed in the left-right direction. After that, since it is distributed and supplied to each flow resistance applying portion 8, a situation in which molten glass is supplied in a concentrated manner in the flow resistance applying chamber 8 in the central portion in the left-right direction is avoided. At this time, the temperature of the molten glass in the distribution chamber 3 is maintained at 1600 ° C. to 1700 ° C., the temperature of the molten glass in the melting furnace 2 (1500 ° C. to 1650 ° C.) and the temperature of the flow resistance imparting chamber 8 (1500 ° C. ˜1650 ° C.). On the other hand, since the inner wall surface of the distribution chamber 3 is covered with platinum or a platinum alloy, the durability against heat does not deteriorate, and the problem of contamination of the molten glass due to eroded foreign matter or foreign glass also arises. Absent.

  Further, each flow resistance application chamber 8 into which molten glass flows from the distribution chamber 3 is provided with a plurality of baffle plates 9, so that it is appropriate for the molten glass flowing through these flow resistance application chambers 8. Resistance is given. Therefore, even when the viscosity and the flow direction of the molten glass passing through the distribution chamber 3 and reaching the respective flow resistance imparting chambers 8 are different from each other, each pressure when being distributed and supplied to each flow resistance imparting chamber 8 is different. Is made uniform by applying the above-mentioned appropriate resistance.

  In addition, since the molten glass flowing through the flow resistance application chamber 8 is subjected to direction change and squeezing action by the baffle plate 9, heat transfer between the molten glasses having different viscosities in the individual flow resistance application chambers 8. Is promoted, and the viscosity of the molten glass is made uniform. In addition, in this flow resistance imparting chamber 8, the temperature of the molten glass is controlled using the temperature detecting means, so that it is possible to supply molten glass having a very accurate viscosity to the molding device 5 in response to the request. Become. Thereby, generation | occurrence | production of shaping | molding defects, such as thickness variation and waviness of the plate glass shape | molded with the shaping | molding apparatus 5, is avoided.

1 Molten glass supply device 2 Melting kiln
2a Outlet of melting furnace 3 Distribution room (distribution section)
4 Branching channel 5 Molding device 8 Flow resistance applying chamber (flow resistance applying section)
9 Baffle plate

Claims (10)

A melting furnace provided with a melting kiln serving as a supply source of molten glass, a distribution unit leading to an outlet of the melting kiln, and a plurality of branch flow paths branched from the distribution unit and extending toward a plurality of molding apparatuses In the glass feeder,
The molten glass has a characteristic that a temperature corresponding to a viscosity of 1000 poise is 1350 ° C. or higher,
In the middle of each branch channel, a molten glass is provided with a flow resistance applying portion in which a plurality of baffle plates for providing flow resistance to the molten glass flowing in each branch channel are fixed. Feeding device.   2. The molten glass supply device according to claim 1, wherein at least a contact surface of the inner wall surface of the flow resistance imparting portion with the molten glass is formed of platinum, molybdenum, palladium, rhodium, or an alloy thereof.   The molten glass supply apparatus according to claim 2, further comprising an electric heating means for heating the molten glass by energizing the platinum, molybdenum, palladium, rhodium or an alloy thereof.   The molten glass supply device according to claim 1, wherein at least a contact surface of the baffle plate with the molten glass is formed of platinum, molybdenum, palladium, rhodium, or an alloy thereof.   The molten glass supply apparatus according to claim 1, wherein the forming apparatus is a sheet glass forming apparatus.   Through a melting step of melting glass having a characteristic corresponding to a viscosity of 1000 poise of 1350 ° C. or more in a melting kiln, and a distribution unit that leads the molten glass flowing out of the melting kiln to an outlet of the melting kiln Distributing step for supplying to a plurality of branch channels and distribution resistance application for imparting distribution resistance by passing the molten glass flowing through the plurality of branch channels through a plurality of baffle plates fixed in each branch channel A glass molding product comprising: a step of forming a glass molded product by supplying a molten glass flowing down the plurality of branch channels to a molding device respectively connected to the plurality of branch channels Production method.   The method for producing a glass molded article according to claim 6, wherein the molten glass is in contact with platinum, molybdenum, palladium, rhodium or an alloy thereof in the flow resistance application step.   The method for producing a glass molded article according to claim 7, wherein the molten glass is heated by energizing the platinum, molybdenum, palladium, rhodium, or an alloy thereof.   The method for producing a glass molded article according to claim 6, wherein at least a contact surface of the baffle plate with the molten glass is formed of platinum, molybdenum, palladium, rhodium, or an alloy thereof.   The method for producing a glass molded product according to any one of claims 6 to 9, wherein the molding step is a plate glass molding step.

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