JP2011121863A - Molten glass supply apparatus and method for producing glass molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molten glass supply apparatus free from the occurrence of problems such as the degradation of a glass molded article or the reduction of product yield which are caused by the formation of two kinds of heterogeneous phases or the chipping of a stirring blade even when the remarkable increase of flow rate of the molten glass is required in a flow passage exclusive for high viscous molten glass. <P>SOLUTION: The molten glass supply apparatus 1 includes a melting furnace 2 as a molten glass supply source and a supply passage 4 for supplying the molten glass flowing out from the melting furnace 2 to a molding unit 3. The molten glass has a feature that a temperature corresponding to 1,000 poise viscosity is ≥1,350°C, a plurality of stirring vessels K1, K2 are independently disposed adjacent to each other in the up to downstream direction in the middle of the supply flow passage 4. The height position of the end part of a stirring blade in the up and down direction in each of stirring vessels K1, K2 is present between the upper end position and the lower end position of each of inflow openings M1, M2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a molten glass supply apparatus and a method for producing a glass molded product, and in particular, an improvement in a supply flow path for supplying molten glass exhibiting high viscosity characteristics from a melting furnace to a molding apparatus, and supply of the molten glass from the melting furnace. The present invention relates to an improvement in a technique for manufacturing a glass molded product by supplying it to a molding apparatus via a flow path.

  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, cover glasses such as laser diodes, and glass substrates for hard disks and filters has rapidly progressed.

  These examples and listed articles and the glass forming these articles (hereinafter also referred to as high-viscosity glass) are optical glass, window glass, and articles such as bottles and tableware that have been used in the past. Compared with glass forming a similar article (hereinafter also referred to as low viscosity glass), its characteristics are greatly different. Specifically, as described in Patent Document 1 below, a high-viscosity glass typified by an alkali-free glass for a liquid crystal display has a temperature corresponding to the viscosity of 1350 when the viscosity is 1000 poise. The low viscosity glass represented by soda-lime glass for containers is a temperature corresponding to the viscosity when the viscosity is 1000 poise, while it exhibits the characteristic that it is 1420 ° C. or higher in the case of a high viscosity or higher, particularly high viscosity. Of 1250 ° C. or lower, particularly 1200 ° C. or lower for low viscosity. Therefore, the above-mentioned high-viscosity glass and low-viscosity glass can be distinguished as being different based on the relationship between temperature and viscosity.

  When manufacturing an article formed of the above-mentioned high-viscosity glass, molten glass made of high-viscosity glass is supplied to a molding apparatus, and, for example, a plate glass used as a glass panel for a liquid crystal display is molded with the molding apparatus. Is done. Therefore, when manufacturing such an article, a molten glass supply apparatus having a high-viscosity dedicated supply channel for supplying molten glass flowing out from a melting furnace serving as a molten glass supply source to a molding apparatus is used. The

  In a melting furnace in this type of molten glass supply device, a heterogeneous phase having a small specific gravity is formed on the surface portion of the molten glass in the melting furnace due to the fact that the glass raw material is not properly melted (for example, melt separation). Due to the erosion of the refractory forming the inner wall of the melting furnace (for example, a high zirconia refractory), a heterogeneous phase having a large specific gravity is formed on the bottom surface of the molten glass in the melting furnace. Or When such molten glass flows out of the melting furnace and is supplied to the molding apparatus as it is through the supply flow path, the quality deteriorates due to the presence of a heterogeneous phase in the glass molded product molded by the molding apparatus, for example, When the glass molded product is a plate glass, the heterogeneous phase portion forms irregularities on the glass surface, leading to a reduction in quality, and in turn, causing frequent occurrence of defective products.

  Therefore, a stirring tank is provided in the middle of the supply flow path in this type of molten glass supply apparatus for the purpose of eliminating the above-mentioned heterogeneous phase of the molten glass and making it homogeneous. Conventionally, only one agitation tank is disposed in the middle of a high-viscosity supply channel, as disclosed in Patent Documents 2, 3, and 4 below. The following Patent Document 5 includes a first flow part having a stirrer at the downstream end of the cooling tank, and a screw having a screw at each of the upstream end and the downstream end of the vacuum degassing tank. 2, the structure provided with the 3rd distribution part and the 4th distribution part which has a blade in the upper stream side end of a homogeneous tank is indicated. Further, in Patent Document 6 below, in the middle of a low-viscosity dedicated supply channel for producing optical glass, plate glass (to be interpreted as window glass for glass), bottle glass, etc. A configuration is disclosed in which one bubble breaker stirring tank is provided between the tanks and two stirring tanks, a homogenization stirring tank and a temperature control tank, are provided downstream of the clarification tank. Furthermore, in the following Patent Document 7 and Patent Document 8, the glass viscosity at the time of stirring is 650 poise (equivalent to 1200 ° C.), and a low-viscosity dedicated glass that supplies low-viscosity molten glass made of soda-lime glass or lead crystal glass is used. A configuration including a plurality of agitation flow sections in the middle of the supply flow path is disclosed.

JP 2004-262745 A JP 2005-511462 A US Patent Application Publication No. 2004/0177649 Japanese Patent Laid-Open No. 2005-60215 Japanese Patent Laid-Open No. 5-208830 Japanese Patent Publication No.43-12885 JP 63-8226 A JP-A-60-27614

  By the way, in recent years, for example, an increase in the size of a plate glass for a liquid crystal display has been promoted, and a glass molded product made of other high-viscosity glass is also intended to improve productivity. The flow rate per unit time of the molten glass supplied to the forming apparatus through the supply channel has rapidly increased. In this way, when the flow rate of the molten glass is increased, in order to eliminate the above-mentioned heterogeneous phase and to homogenize the molten glass, it is necessary to increase the stirring ability in the stirring tank. Therefore, the present inventors tried to increase the rotation speed of the stirring blade in order to meet such a request. However, since the molten glass is highly viscous, increasing the number of revolutions of the stirring blade in this molten glass increases the load on the stirring means (stirrer) body and causes a fatal trouble such as breakage. It becomes. Further, the resistance acting on the stirring blade becomes unreasonably large, the stirring blade is scraped, and the cut foreign matter (usually platinum) is mixed into the molten glass, and this foreign matter causes a defect in the glass molded product. In order to reduce the resistance to the stirring blade, operation at a higher temperature may be considered. However, with such a method, the mechanical strength of platinum or the like that is the material of the stirring blade is not sufficient, and the same problem is caused. It came to the conclusion that occurs.

  As another measure for dealing with this type of problem, according to the above-mentioned Patent Document 2, it has been proposed to improve the shape of the stirring blade to reduce the excision amount of the noble metal foreign matter. Under the restriction that the stirring blades must be rotated in the molten glass, there is a limit to such a method, and it is impossible to cope with a large increase in the flow rate of molten glass in recent years.

  Due to the above circumstances, in the past, when a problem related to an increase in the flow rate as described above occurs in a supply channel dedicated to high viscosity, a set of equipment including a melting kiln, a supply channel, and a molding device is used. However, it was only trying to solve the problem by adding another one.

  In the above-mentioned Patent Document 5, there are a first flow part having a stirrer, second and third flow parts having a screw, and a fourth flow part having blades in the middle of a supply channel dedicated to high viscosity. Although it is arranged, the first flow part performs the action of changing the occluded gas contained in the molten glass into bubbles in the previous step of stirring the molten glass to make it homogeneous. Both the second and third flow sections perform an action of pushing down the molten glass to be raised. Accordingly, since only the fourth flow section performs the homogenizing action of the molten glass, even with the technique described in Patent Document 5, it is possible to eliminate the heterogeneous phase and achieve sufficient homogenization. It becomes extremely difficult. Therefore, in this case as well, in order to cope with a recent increase in the flow rate of molten glass, a set of equipment including a supply flow path, a melting furnace, and a molding apparatus having the same configuration as that disclosed in the same document is used. It must be added separately.

  On the other hand, in the low-viscosity dedicated supply channel, the resistance received by the rotation of the stirring blade is much smaller than in the case of the above-mentioned high-viscosity glass, and the temperature of the molten glass is low. Even when it is necessary to increase the flow rate of the glass, there is no problem of deterioration of the quality of the glass molded product and product yield due to breakage of the stirrer, scraping of the stirring blades.

  Therefore, when trying to increase the flow rate of the molten glass, problems related to the presence of a heterogeneous phase, stirrer breakage, stirring blade scraping, etc., have a high viscosity dedicated supply flow path. It is an inherent problem. In other words, the highly viscous molten glass flowing through this supply channel has the characteristics that the flowability is hindered even by a slight temperature drop, and it easily shifts to a state where stirring by stirring blades is difficult. It is not preferable to change the basic configuration of the supply channel. Therefore, the high-viscosity dedicated supply channel disclosed in Patent Document 5 already described is not provided with a new tank, but is merely an improvement of a part of the existing tank. Considering the above matters, in order to cope with the increase in the flow rate of the molten glass, it has been considered optimal to take measures such as adding another set of facilities as described above.

  In contrast, in the low-viscosity dedicated supply flow path, even if a slight temperature change occurs, the fluidity of the molten glass is not adversely affected, so the basic configuration of the supply flow path can be easily changed. Therefore, in Patent Documents 6, 7, and 8 described above, various types and numbers of tanks are provided in a supply channel dedicated to low viscosity. However, in the field of manufacturing a glass molded product made of high-viscosity glass, if such a configuration is adopted, the fluidity of the molten glass deteriorates and the molding operation by the molding apparatus, and thus the defects that are extremely conspicuous in the glass molded product. It is considered inevitable that such an idea has become common sense. For this reason, if attention is paid to the configuration of the supply channel dedicated to high viscosity, no effective measures against the increase in the flow rate of the molten glass are actually taken.

  Therefore, the first problem of the present invention is that even when there is a request for a significant increase in the flow rate of the molten glass by applying an effective improvement that has been impossible in the past to the supply channel dedicated to high viscosity. It is intended to prevent problems such as deterioration of the quality of the glass molded product and product yield due to the presence of the heterogeneous phase and the scraping of the stirring blade.

  In addition, in Patent Document 5 described above, the first to fourth circulation portions that perform agitation are provided in the supply channel dedicated to high viscosity. It is formed as a part of a defoaming tank and a homogeneous tank. For this reason, since the stirring flow part cannot be handled in an independent state, maintenance, inspection, repair or replacement becomes troublesome and cumbersome, and the stirring flow part of the stirring flow part is appropriately adjusted so that the resistance acting on the stirring blades from the molten glass is appropriate. Even when the temperature is adjusted, the entire tank is affected, and there is a possibility that it is difficult to adjust the temperature of the molten glass flowing through the stirring flow part, and thus to optimize the viscosity.

  Note that such a problem, particularly the problem related to the difficulty in optimizing the viscosity, is a problem inherent to the high-viscosity dedicated supply flow path and cannot occur in the low-viscosity dedicated supply flow path. It can be said that it is a problem. That is, as already described, in the supply channel dedicated to low viscosity, the basic configuration can be changed relatively freely. Various types and numbers of tanks are provided in the supply flow path. However, in the field of high-viscosity glass, adopting such a configuration was thought to inevitably cause a fatal defect in the molding operation of the molding apparatus and the glass molded product. For this reason, no effective countermeasures against such a problem have been taken with respect to the configuration of the supply flow path dedicated to high viscosity.

  Accordingly, the second problem of the present invention is that maintenance, inspection, repair, or replacement of the stirring flow section is easily performed by providing an effective improvement, which has been impossible in the past, to the supply channel dedicated to high viscosity. It is possible to easily optimize the resistance of the molten glass acting on the stirring blade.

  An apparatus according to the present invention, which was created to solve the first and second problems, supplies a molten kiln serving as a molten glass supply source and molten glass flowing out of the molten kiln to a molding apparatus. In the molten glass supply apparatus provided with a supply flow path, the molten glass has a characteristic that a temperature corresponding to a viscosity of 1000 poise is 1350 ° C. or more, and is in an independent state in the middle of the supply flow path. Are arranged adjacent to each other in the upstream / downstream direction, and each of the plurality of stirring tanks includes a peripheral wall portion and a bottom wall portion whose inner peripheral surfaces are cylindrical surfaces, and the peripheral wall portions thereof. The inlet and outlet of the molten glass are formed respectively, and one inlet and the other outlet of the adjacent agitation tanks are connected via a communication path, and the stirring blades accommodated inside them are connected. Height position at the end in the vertical direction But it characterized in that there between the opening upper end position and the opening lower end position of the respective inlet.

  In this case, “the plurality of stirring tanks arranged adjacent to each other in the upstream / downstream direction” means that no other tank exists between the adjacent stirring tanks. The communication state between the adjacent agitation tanks is not particularly limited, but the adjacent agitation tanks are in direct communication with each other, that is, a communication channel mainly serving as a passage. It is preferable that only the connection is made. However, it is not excluded that the communication channel is provided with a baffle plate or the like in the middle thereof. Moreover, it is preferable that the channel area of this communication channel is smaller than the channel area of a stirring tank. In addition, the above-mentioned “multiple stirring tanks that are individually independent” means that the part that performs the stirring action does not exist as a part of the tank, but the entire tank performs the stirring action. It means that each is composed.

Here, since the object to be supplied by this apparatus is a molten glass having a characteristic that the temperature corresponding to a viscosity of 1000 poise is 1350 ° C. or higher, this glass is clear from the matters already described. High-viscosity glass is distinguished from low-viscosity glass. If the molten glass has a characteristic that the temperature corresponding to a viscosity of 1000 poise is 1420 ° C. or more, it is advantageous in that the distinction from the low-viscosity glass can be made clearer. An example of such a highly viscous glass is an alkali-free glass (a glass having an alkali component of 0.1% by mass or less, particularly 0.05% by mass or less). Specifically, in _{mass%, SiO 2: 40~70%,} Al 2 O 3: 6~25%, B 2 O 3: 5~20%, MgO: 0~10%, CaO: 0~15% BaO: 0 to 30%, SrO: 0 to 10%, ZnO: 0 to 10%, fining agent: alkali-free glass containing 0 to 5%, more preferably, by mass%, SiO ₂ : 55 to 70% _{, Al 2 O 3: 10~20%} , B 2 O 3: 5~15% ,: MgO: 0~5%, CaO: 0~10%, BaO: 0~15%, SrO: 0~10%, Non-alkali glass containing ZnO: 0 to 5%, fining agent: 0 to 3% can be mentioned.

  According to such a configuration, since the plurality of stirring tanks are arranged adjacent to each other in the upstream and downstream directions in the supply channel dedicated to high viscosity, for example, the plate glass for a liquid crystal display is made larger, Even when the flow rate per unit time of the molten glass supplied to the molding device through the supply channel is increased, the molten glass is mixed with a plurality of agitators in order to cope with the productivity improvement of the glass molded product made of high-viscosity glass. By passing through the tank, the stirring ability and thus the homogenization ability is enhanced. In addition, the height position of the vertical ends of the stirring blades respectively accommodated in the plurality of stirring tanks is between the opening upper end position and the opening lower end position of the inlet formed in each of the peripheral wall portions. Since it exists, the homogenization ability of molten glass is efficiently improved (details are described in the section of [Description of Embodiments]). Accordingly, the heterogeneous phase generated due to the high-viscosity glass, for example, the two kinds of heterogeneous phases of the surface phase having a small specific gravity and the heterogeneous phase of the bottom surface having a large specific gravity are appropriately eliminated, It becomes possible to achieve sufficient homogenization of the highly viscous molten glass. As a result, the deterioration of the quality of the glass molded product due to the presence of a heterogeneous phase in the molten glass supplied to the molding apparatus (for example, the formation of irregularities due to the presence of the heterogeneous phase when the glass molded product is plate glass) is effective. To be avoided. In addition, when there are a plurality of stirring tanks in this way, the total stirring ability (homogenization ability) can be sufficiently increased without increasing the number of revolutions of the stirring blade per stirring tank. It is possible to greatly increase the homogenization effect while keeping the resistance acting on the stirring blade from the glass small. As a result, the stirrer blade is scraped by the resistance of the high-viscosity molten glass, and the cut foreign matter (platinum, etc.) is mixed into the molten glass. To be suppressed. The advantages as described above can be enjoyed only because the supply channel is dedicated to high viscosity, and the supply channel dedicated to low viscosity does not cause any problems in the first place. Of course, the benefits are not enjoyable.

  Furthermore, according to such a configuration, since a plurality of individual agitation tanks are arranged in the middle of the supply channel dedicated to high viscosity, each agitation tank can be handled in an independent state. As a result, it is possible to easily and easily perform maintenance inspection, repair or replacement. In addition, even when adjusting the temperature of the stirring unit to appropriately adjust the resistance acting on the stirring blade from the molten glass, compared to the conventional (exclusive supply channel for high viscosity disclosed in Patent Document 5 described above). In the individual tanks, the stirring unit is not easily affected by other parts, and the temperature of the molten glass flowing through the stirring unit (stirring tank) and thus the viscosity can be adjusted easily and appropriately. In this case as well, the above-mentioned advantages, particularly the advantages relating to the adjustment of the viscosity, can be enjoyed because the supply channel is exclusively for high viscosity. As a matter of course, the above-mentioned advantages cannot be enjoyed.

  In this case, with respect to the adjacent stirring tanks in the plurality of stirring tanks, an inlet is formed in one of the upper peripheral wall portion and the lower peripheral wall portion of the upstream stirring tank, and an outlet is formed in the other. The inlet and outlet of the agitation tank are formed so that the upper and lower parts are the same as the inlet and outlet of the upstream agitation tank, and the outlet of the upstream agitation tank and the outlet are It is possible to connect the inlet of the downstream stirring tank having the opposite part via the communication path (hereinafter referred to as the first connection form).

  In addition, for the adjacent stirring tanks in the plurality of stirring tanks, an inlet is formed in one of the upper peripheral wall portion and the lower peripheral wall portion of the upstream stirring tank, and an outlet is formed in the other, and the downstream stirring is performed. The inlet and outlet of the tank are respectively formed upside down from the inlet and outlet of the upstream stirring tank, and the outlet of the upstream stirring tank and the outlet are It is possible to connect the inlet of the downstream stirring tank having the same part via a communication path (hereinafter referred to as a second connection configuration).

  Furthermore, about the said some stirring tank, the above-mentioned 1st connection form and 2nd connection form can also be arranged in parallel adjacently.

  In the above configuration, it is preferable that all of the plurality of stirring tanks are configured to perform a homogenizing action.

  Moreover, in the above structure, it is preferable that the outer peripheral end of the stirring blade accommodated in the stirring vessel is close to the inner peripheral surface.

  In the above configuration, all of the plurality of stirring tanks are reversed (upward or downward) with respect to the forward flow (downward or upward) of the molten glass by the stirring blades housed inside the stirring tank. It is preferable that the resistor is provided with a resistance of

  In this way, since the stirring blade stirs the molten glass in a manner that prevents the flow of the molten glass, the molten glass is stirred by the stirring blade as compared with the case where the directionality is reversed. The time for receiving becomes longer, and sufficient stirring performance can be obtained.

  In the above configuration, the temperature of the molten glass flowing through all of the plurality of stirring tanks is preferably 1350 to 1550 ° C.

  That is, when the temperature of the molten glass is excessively low, the viscosity becomes unreasonably high, the stirring blade is scraped by the resistance of the molten glass, and a fatal defect that the cut foreign matter is mixed in the molten glass On the other hand, when the temperature of the molten glass is excessively high, the stirring blades are prematurely deteriorated and the durability is lowered. In consideration of such matters, it is preferable that the temperature of the molten glass flowing inside all of the plurality of stirring tanks is within the above numerical range, and if the lower limit is 1400 ° C and the upper limit is 1500 ° C, more preferable results are obtained. can get.

  Furthermore, it is preferable that the viscosity of the molten glass flowing through all of the plurality of stirring tanks is 300 to 7000 poise.

  That is, if the viscosity of the molten glass is excessively low, the temperature is unreasonably high, leading to premature deterioration of the stirring blade and a decrease in durability, while the viscosity of the molten glass is excessively high. This causes a fatal defect that the stirring blade is scraped by the resistance of the molten glass and the cut foreign matter is mixed into the molten glass. In consideration of such matters, it is preferable that the viscosity of the molten glass flowing inside all of the plurality of stirring tanks is within the above numerical range, and more preferable results are obtained when the lower limit is 700 poise and the upper limit is 4000 poise. can get.

  And in the above structure, the plate glass shape | molded with the said shaping | molding apparatus can further enjoy the effect of this invention, when using both front and back both surfaces in an unpolished state.

  That is, when used in an unpolished state, the homogeneity of the glass directly determines the surface quality of the glass. Therefore, when the apparatus of the present invention is used, for example, the above-mentioned heterogeneous phase on the surface portion and the heterogeneous phase on the bottom surface in the high-viscosity molten glass are subjected to stirring action in a plurality of stirring tanks (especially homogeneous tanks). Thus, since these heterogeneous phases cause the defects, both the unpolished front and back surfaces of the plate glass are defective, and the generation of defective products can be effectively suppressed.

  The method according to the present invention, which was created to solve the first and second problems described above, uses a high-viscosity glass having a characteristic that a temperature corresponding to a viscosity of 1000 poise is 1350 ° C. or more in a melting kiln. When the molten glass flows through the melting step for melting and the supply flow path leading from the melting furnace to the molding apparatus on the downstream side, a plurality of stirring tanks that are individually independent are arranged adjacent to the upstream and downstream sides. An agitation step for allowing the molten glass to flow into and through the agitating tank arrangement site in the middle of the supply flow path, and molding for forming a glass molded product by supplying the molten glass agitated in the agitation step to a molding apparatus And in the stirring step, each of the plurality of stirring tanks includes a peripheral wall portion and a bottom wall portion whose inner peripheral surface is a cylindrical surface, and a molten glass inflow port is provided in each of the peripheral wall portions. And the outlet The one inlet and the other outlet of the adjacent stirring tanks are connected via a communication path, and the height position of the vertical ends of the stirring blades housed inside them is It is characterized in that molten glass flows into and out of the plurality of stirring tanks in a state existing between the upper end position of the opening and the lower end position of the opening.

  The components of this method and the various items related to them are substantially the same as those already described with respect to the above apparatus, so that the description thereof is omitted here for convenience.

  As described above, according to the molten glass supply apparatus according to the present invention, since the stirring tank is disposed adjacent to the upstream and downstream directions in the supply channel dedicated to high viscosity, the molten glass flowing through the supply channel Even when the flow rate is increased, the molten glass passes through a plurality of stirring tanks, whereby the stirring ability and thus the homogenization ability is enhanced. In particular, the height positions of the vertical ends of the stirring blades respectively housed in the plurality of stirring tanks exist between the opening upper end position and the opening lower end position of the inlet formed in each of the peripheral wall portions. Therefore, the heterogeneous phase generated due to the high viscosity glass can be appropriately eliminated, and the molten glass can be sufficiently homogenized. In addition, when there are a plurality of stirring tanks in this way, the total stirring ability (homogenization ability) can be sufficiently increased without increasing the number of revolutions of the stirring blade per stirring tank. The stirrer blade is scraped by the resistance of the glass, and the cut foreign matter (platinum or the like) is mixed into the molten glass, thereby effectively preventing a problem that a fatal defect occurs in the glass molded product.

  In addition, according to the molten glass supply apparatus according to the present invention, since a plurality of individual agitation tanks are arranged in the middle of the supply channel dedicated for high viscosity, each agitation tank is independent. Thus, it is possible to easily and easily perform maintenance, inspection, repair or replacement. Moreover, even when adjusting the temperature of the agitation unit so that the resistance acting from the molten glass on the agitation blade is appropriate, the agitation unit is less susceptible to the influence of other parts in the individual tanks. It is possible to easily and appropriately adjust the temperature of the molten glass flowing through the glass) and thus the viscosity.

  On the other hand, according to the manufacturing method of the glass molded product which concerns on this invention, there exists an effect substantially the same as said molten glass supply apparatus.

It is a front view which shows schematic structure of the molten glass supply apparatus which concerns on 1st Embodiment of this invention. It is a vertical front view which shows the principal part of the 1st stirring tank which is a component of the molten glass supply apparatus which concerns on the said 1st Embodiment. It is a schematic longitudinal front view which shows the state which a molten glass flows through the inside of the 1st, 2nd stirring tank which is a component of the molten glass supply apparatus which concerns on the said 1st Embodiment. It is a front view which shows schematic structure of the principal part of the molten glass supply apparatus which concerns on 2nd Embodiment of this invention. It is a front view which shows schematic structure of the principal part of the molten glass supply apparatus which concerns on 3rd Embodiment of this invention. It is a front view which shows schematic structure of the principal part of the molten glass supply apparatus which concerns on 4th Embodiment of this invention. It is a vertical front view which shows the principal part of the 2nd stirring tank which is a component of the molten glass supply apparatus which concerns on the said 4th Embodiment. It is a schematic longitudinal front view which shows the state which a molten glass flows through the inside of the 1st, 2nd stirring tank which is a component of the molten glass supply apparatus which concerns on the said 4th Embodiment. It is a front view which shows schematic structure of the principal part of the molten glass supply apparatus which concerns on 5th Embodiment of this invention. It is a front view which shows schematic structure of the principal part of the molten glass supply apparatus which concerns on 6th Embodiment of this invention. It is a front view which shows schematic structure of the principal part of the molten glass supply apparatus which concerns on 7th Embodiment of this invention. It is a front view which shows schematic structure of the principal part of the molten glass supply apparatus which concerns on 8th Embodiment of this invention. It is a graph which shows the effect | action of the molten glass supply apparatus which concerns on 1st-8th embodiment of this invention. It is a graph which shows the effect | action of the molten glass supply apparatus which concerns on 1st-8th embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, based on FIG. 1, schematic structure of the molten glass supply apparatus which concerns on 1st Embodiment of this invention is demonstrated. As shown in the figure, a molten glass supply apparatus 1 includes a melting furnace 2 that is disposed at an upstream end and melts a glass raw material, and has a high viscosity molten glass that flows out of the melting furnace 2 (corresponding to a viscosity of 1000 poise). The temperature of 1350 ° C. or higher) is supplied through the supply channel 4 to the molded body of the molding apparatus 3 for molding the sheet glass by the overflow down draw method. Specifically, as the high viscosity glass supplied here, for example, in mass%, SiO ₂ 60%, Al ₂ O ₃ 15%, B ₂ O ₃ 10%, CaO 5%, BaO 5%, SrO. An alkali-free glass having a composition of 5% and a temperature corresponding to a viscosity of 1000 poise of about 1450 ° C. can be used. In the supply flow path 4, a clarification tank 5 leading to the downstream side of the melting furnace 2 at the upstream end is disposed, and the first agitation on the upstream side in an independent state is provided immediately downstream of the clarification tank 5. The tank K1 and the downstream second stirring tank K2 are arranged adjacent to each other in the upstream and downstream directions. Both of these two agitation tanks K1 and K2 are structured to perform a homogenizing action. Furthermore, in any of these two cases, the temperature of the molten glass flowing inside the stirring tanks K1 and K2 is 1350 to 1550 ° C. (preferably 1400 to 1500 ° C.), and the viscosity is 300 to 7000 poise (preferably 700 to 4000 poise). From the downstream side of the second agitation tank K2, molten glass is supplied to the molded body of the molding apparatus 3 through the cooling pipe 7, the pot (not shown), the small diameter pipe, and the large diameter pipe, and melted in this molded body. It is set as the structure which shape | molds glass in plate shape. And the plate glass obtained by shaping | molding with this shaping | molding apparatus 3 turns into a product in the state in which front and back both surfaces are an unpolished surface.

  Each of the first and second stirring tanks K1 and K2 contains first and second stirring means S1 and S2 made of a single stirrer, and the inner peripheral surfaces of the tanks K1 and K2 are located in the entire vertical direction. Each of the inner peripheral surfaces is in close proximity to the outer peripheral ends of the first and second stirring means (respective stirring blades) S1 and S2. The first stirring tank K1 and the second stirring tank K2 both have a cylindrical peripheral wall and a bottom wall formed of platinum or a platinum alloy, and the two tanks K1, K2 have a size, a shape, And the internal structure is the same or substantially the same. And the clarification channel | path 10 which goes downstream from the clarification tank 5 is connected to the upper part (upper end part of a surrounding wall) of the 1st stirring tank K1, and the lower part (lower end part of a surrounding wall) of the 1st stirring tank K1 and 2nd. A cooling pipe (cooling passage) 7 is connected to the upper portion (upper end portion of the peripheral wall) of the stirring tank K2 via the first communication path R1, and the lower portion (lower end portion of the peripheral wall) of the second stirring tank K2 communicates with the pot. It is connected. Therefore, the molten glass that has flowed into the inside of the first stirring tank K1 from the clarification passage 10 through the first inlet M1 formed in the upper part of the first stirring tank K1 flows downward in the first stirring tank K1, After flowing out to the first communication path R1 through the first outlet N1 formed in the lower part of the stirring tank K1, and flowing obliquely upward through the first communication path R1, the second stirring tank K2 is passed through the first communication path R1. The second inflow port N2 formed in the lower part of the second stirring tank K2 after flowing into the inside through the second inflow port M2 formed in the upper part and flowing downward in the second stirring tank K2. Through the cooling passage 7. In addition, each said inlet is formed in the upstream part of the surrounding wall of each stirring tank, and each outlet is formed in the downstream part of the surrounding wall of each stirring tank, and each inlet and each outlet The channel area is set smaller than the channel area inside each agitation tank (the same applies to each inlet and outlet in the following embodiments).

  In this case, as shown in FIG. 2, the molten glass flowing into the inside from the first inflow port M1 of the first stirring tank K1 is partly passed through the path indicated by the arrow A immediately after the first stirring. The position of each part is set so that the uppermost stirring blade S11 of the means S1 contacts the uppermost stirring blade S11 and the remaining portion flows through the path indicated by the arrow B into the portion above the uppermost stirring blade S11. In other words, the height position of the upper end of the uppermost stirring blade S11 in the first stirring tank K1 (the vertical ends of all the stirring blades) is the upper opening position and the lower opening position of the first inlet M1. Exist between. Further, the molten glass flowing into the second inlet M2 of the second stirring tank K2 also has a part of the molten glass at the uppermost stage of the second stirring means S2, as in the first stirring tank K1. The position of each part is set so that the remaining part flows into the part above the uppermost stirring blade S21 while being in contact with the blade S21. And for the molten glass which flows into the first stirring tank K1 and the second stirring tank K2 and flows downward in the inside, both the first stirring means S1 and the second stirring means S2 are upward. It is comprised so that the resistance which turns may be provided, ie, the resistance of the direction opposite to the flow of a molten glass may be provided.

  In order to manufacture plate glass as a glass molded product using the molten glass supply apparatus 1 having the above-described configuration, a melting step of melting high-viscosity glass in the melting furnace 2, and a downstream side of the melting furnace 2 When the molten glass flows through the supply channel 4 leading to the molding device 3, the molten glass flows into the first and second stirring tanks K1 and K2 that are in an independent state and perform a homogenizing action. The process and the shaping | molding process which supplies the molten glass stirred by this stirring process to the shaping | molding apparatus 3, and shape | molds plate glass are performed.

  Next, the agitation process in the first embodiment will be described in detail.

  The molten glass flowing out from the melting furnace 2 and flowing into the clarification tank 5 (see FIG. 1) first flows into the first stirring tank K1 from the clarification passage 10 through the first inlet M1, and rotates. After flowing downward in the first stirring tank K1 while being stirred by S1, it flows out from the first outlet N1 and flows obliquely upward in the first communication path R1. Thereafter, the molten glass flows from the first communication path R1 into the second stirring tank K2 through the second inlet M2, and is moved downward in the second stirring tank K2 while being stirred by the rotating second stirring means S2. Then, it flows out from the second outlet N2 and reaches the cooling passage 7.

  FIG. 3 shows a simulation experiment (model experiment) on the mode of molten glass flowing while receiving the stirring action by the first and second stirring means S1 and S2 in the first and second stirring tanks K1 and K2 as described above. It is the schematic which shows the result of having performed. The path indicated by the alternate long and short dash line with the symbol C in the figure is the path through which the molten glass existing in the upper part of the clarification passage 10, that is, the molten glass containing the heterogeneous phase suspended in the surface portions of the melting furnace 2 and the clarification tank 5. The path indicated by the broken line with the symbol D in the same figure was sunk in the molten glass existing in the lower part of the clarification passage 10, that is, the bottom of the melting furnace 2 and the clarification tank 5. The path | route through which the molten glass containing a heterogeneous phase flows is represented typically.

  As can be seen from the figure, the molten glass existing in the upper part of the clarification passage 10 first flows into the first stirring tank K1 from the upper part of the first inlet M1, and the central part (the peripheral part of the central axis) is moved downward. , Flows out from the lower part of the first outlet N1, flows obliquely upward in the vicinity of the lower surface of the first communication path R1, and then enters the second stirring tank K2 from the lower part of the second inlet M2. After flowing in and flowing downward in the vicinity of the inner peripheral surface, it flows out from the upper portion of the second outlet N2 and flows in the vicinity of the upper surface portion of the cooling passage 7. On the other hand, after the molten glass existing in the lower part of the clarification passage 10 first flows into the first stirring tank K1 from the lower part of the first inlet M1, and flows downward in the vicinity of the inner peripheral surface thereof, It flows out from the upper part of the 1st outflow port N1, flows in the upper surface part vicinity of 1st communicating path R1 diagonally upward, and then flows in into the 2nd stirring tank K2 from the upper part of the 2nd inflow port M2, and the center part is passed. After flowing downward, it flows out from the lower portion of the second outlet N2 and flows in the vicinity of the lower surface portion of the cooling passage 7.

  In this case, in the first agitation tank K1 and the second agitation tank K2, the molten glass flowing from the upper part to the lower part contacts the rotating first agitation means S1 and second agitation means S2. In contrast to the sufficient stirring action, the molten glass flowing from the top to the bottom in the vicinity of each inner peripheral surface does not come into contact with the first stirring means S1 and the second stirring means S2. I will not receive it. Therefore, while the molten glass existing in the upper part of the clarification passage 10 flows along the path indicated by the symbol C (path indicated by the alternate long and short dash line), the molten glass is sufficiently stirred inside the first stirring tank K1. The molten glass existing in the lower part of the clarification passage 10 is sufficiently stirred inside the second stirring tank K2 while flowing along the path indicated by the symbol D (path indicated by the broken line). As a result, the heterogeneous phase having a small specific gravity existing on the surface portion of the molten glass in the melting furnace 2 and the clarification tank 5 is sufficiently stirred inside the first stirring tank K1 and disappears, whereby the surface portion of the molten glass is removed. While becoming homogeneous, the heterogeneous phase having a large specific gravity present on the bottom surface portion of the molten glass is sufficiently stirred inside the second stirring tank K2 and disappears, thereby making the bottom surface portion of the molten glass homogeneous, and consequently Homogenization is achieved throughout the molten glass.

  FIG. 4 is a schematic front view showing the main part of the molten glass supply apparatus according to the second embodiment of the present invention. The molten glass supply apparatus 1 according to the second embodiment is different from the molten glass supply apparatus 1 according to the first embodiment described above in the middle of the supply flow path 4 in the first stirring tank K1 and the first stirring tank K1. In addition to the two stirring tanks K2, a third stirring tank K3 having the same or substantially the same size, shape and internal structure as those tanks K1, K2 is disposed on the downstream side of the third stirring tank K3. This is the point where the cooling passage 7 is communicated with the downstream side. Specifically, the lower part of the second stirring tank K2 (lower end of the peripheral wall) and the upper part of the third stirring tank K3 (upper end of the peripheral wall) are connected via the second communication path R2, and the third stirring tank A cooling passage 7 is connected to the lower part of K3 (the lower end of the peripheral wall). Therefore, the molten glass that has flowed out through the second outlet N2 of the second stirring tank K2 flows obliquely upward through the second communication path R2, and then forms on the upper part of the third stirring tank K3 from the second communication path R2. After flowing into the inside of the third inlet M3 and flowing downward in the third stirring tank K3, the cooling passage 7 is passed through the third outlet N3 formed in the lower part of the third stirring tank K3. It has come to leak.

  In the case of producing a plate glass as a glass molded product using the molten glass supply device 1 according to the second embodiment, as in the case of the above-described first embodiment, a melting step, a stirring step, The molding process is executed. In the stirring step, the first stirring means S1 and the second stirring means S2 in which the molten glass rotates in the first stirring tank K1 and the second stirring tank K2, as in the case of the first embodiment described above. The stirred molten glass is further stirred by the rotating third stirring means S3 inside the third stirring tank K3. Then, referring to the result of the simulation experiment shown in FIG. 3 described above, the molten glass flow in the third stirring tank K3 is substantially the same as that in the first stirring tank K1. That is, in the molten glass that flows out from the second outlet N2 of the second stirring tank K2 and flows obliquely upward through the second communication path R2, it exists in the vicinity (upper part) of the upper surface of the second communication path R2. Molten glass (the molten glass originally present in the upper part of the clarification passage 10) flows into the third stirring tank K3 through the upper part of the third inlet M3, and the central part of the inner part is directed downward from above. After flowing, it flows out from the lower part of the third outlet N3 and reaches the vicinity of the lower surface of the cooling passage 7. On the other hand, the molten glass existing in the vicinity (lower part) of the lower surface portion of the second communication path R2 (the molten glass originally existing in the lower part of the clarification passage 10) passes through the lower part of the third inlet M3. After flowing into the third stirring tank K3 and flowing in the vicinity of the inner peripheral surface from the upper side to the lower side, it flows out from the upper part of the third outlet N3 and reaches the vicinity of the upper surface of the cooling passage 7. Therefore, compared with the case of the above-mentioned 1st Embodiment, it can be anticipated that the stirring action with respect to the heterogeneous phase of the surface part of the molten glass in the melting furnace 2 and the clarification tank 5 and thus the homogenizing action can be performed more accurately. .

  FIG. 5 is a schematic front view showing the main part of the molten glass supply apparatus according to the third embodiment of the present invention. The molten glass supply apparatus 1 according to the third embodiment is different from the molten glass supply apparatus 1 according to the second embodiment described above in the middle of the supply flow path 4 in the first, second, and second. In addition to the three stirring tanks K1, K2, and K3, a fourth stirring tank K4 having the same or substantially the same size, shape, and internal structure as those tanks K1, K2, and K3 is disposed on the downstream side thereof. The cooling passage 7 is communicated with the downstream side of the fourth stirring tank K4. More specifically, the lower part of the third stirring tank K3 (lower end of the peripheral wall) and the upper part of the fourth stirring tank K4 (upper end of the peripheral wall) are connected via the third communication path R3, and the fourth stirring tank A cooling passage 7 is connected to the lower part of K4 (the lower end of the peripheral wall). Accordingly, the molten glass that has flowed out through the third outlet N3 of the third stirring tank K3 flows obliquely upward through the third communication path R3 and then forms on the upper part of the fourth stirring tank K4 from the third communication path R3. After flowing into the fourth inlet M4 and flowing downward in the fourth stirring tank K4, the cooling passage 7 is passed through the fourth outlet N4 formed in the lower part of the fourth stirring tank K4. It has come to leak.

  In the case of producing a plate glass as a glass molded product using the molten glass supply apparatus 1 according to the third embodiment, as in the case of the above-described first embodiment, a melting step, a stirring step, The molding process is executed. In the agitation step, the first, second, and third rotating glass is rotated in the first, second, and third agitation tanks K1, K2, and K3 as in the case of the second embodiment described above. The agitated molten glass is further agitated by the rotating fourth agitating means S4 inside the fourth agitating tank K4 while being agitated by the 3 agitating means S1, S2, S3. Then, referring to the result of the simulation experiment shown in FIG. 3 described above, the form of the molten glass flow in the fourth stirring tank K4 is substantially the same as that in the second stirring tank K2. That is, in the molten glass that flows out from the third outlet N3 of the third stirring tank K3 and flows obliquely upward in the third communication path R3, it exists in the vicinity (lower part) of the lower surface portion of the third communication path R3. Molten glass (the molten glass originally present in the upper part of the clarification passage 10) flows into the fourth stirring tank K4 through the lower part of the fourth inlet M4, and the vicinity of the inner peripheral surface thereof is directed downward from above. After flowing, it flows out from the upper part of the fourth outlet N4 and reaches the vicinity of the upper surface part of the cooling passage 7. On the other hand, the molten glass existing in the vicinity (upper part) of the upper surface portion of the third communication path R3 (the molten glass originally existing in the lower part of the clarification passage 10) passes through the upper part of the fourth inlet M4. After flowing into the fourth agitation tank K4 and flowing from the upper part toward the lower part in the inside, it flows out from the lower part of the fourth outlet N4 and reaches the vicinity of the lower surface part of the cooling passage 7. Therefore, compared with the case of the above-mentioned 2nd Embodiment, the stirring action with respect to the heterogeneous phase of the bottom face part of the molten glass in the melting furnace 2 and the clarification tank 5, and hence the homogenization action, and the case of the above-mentioned 1st Embodiment In comparison, it can be expected that the agitation action and thus the homogenization action on the two kinds of heterogeneous phases of the surface portion and the bottom portion can be performed more accurately.

  FIG. 6 is a schematic front view showing the main part of the molten glass supply apparatus according to the fourth embodiment of the present invention. The molten glass supply apparatus 1 according to the fourth embodiment differs from the molten glass supply apparatus 1 according to the first embodiment described above in the passage around the first stirring tank K1 and the second stirring tank K2. The configuration is basically different. More specifically, the clarification passage 10 going downstream from the clarification tank 5 is connected to the upper part (the upper end part of the peripheral wall) of the first stirring tank K1, and the lower part (the lower end part of the peripheral wall) of the first stirring tank K1. The lower part (lower end of the peripheral wall) of the second stirring tank K2 is connected via the fourth communication path R4, and the upper part (upper end part of the peripheral wall) of the second stirring tank K2 is connected to the cooling passage 7 leading to the pot. ing. Therefore, the molten glass that has flowed into the interior of the first stirring tank K1 from the clarification passage 10 through the first inlet M1 flows downward in the first stirring tank K1, and then flows into the first stirring tank K1. After flowing out to the fourth communication path R4 through the first outlet N1 formed in the lower part of the first flow path, flowing in the substantially horizontal direction through the fourth communication path R4, the lower part of the second stirring tank K2 from the fourth communication path R4 So as to flow into the cooling passage 7 through the second outlet N2 at the upper part of the second stirring tank K2. It has become.

  In this case, as shown in FIG. 7, the molten glass flowing into the inside from the second inlet M <b> 2 of the second stirring tank K <b> 2 immediately after flowing in, partly passes through the path indicated by the arrow E for the second stirring. The position of each part is set so that it abuts on the lowermost stirring blade S21 of the means S2 and the remaining part flows through the path indicated by the arrow F into the part below the lowermost stirring blade S21. In other words, the height position of the lower end of the uppermost stirring blade S21 in the second stirring tank K2 (the vertical ends of all the stirring blades) is the upper opening position and the lower opening position of the second inlet M2. Exist between. In addition, the aspect immediately after inflow of the molten glass which flows in into the inside from the 1st inflow port M1 of the 1st stirring tank K1 is the same as the matter already demonstrated based on FIG. And, for the molten glass that flows into the first stirring tank K1 and flows downward in the inside thereof, the first stirring means S1 is configured to give resistance upward, The second stirring means S2 is configured to give a downward resistance to the molten glass that flows into the second stirring tank K2 and flows upward in the interior thereof.

  In the case of producing a plate glass as a glass molded product using the molten glass supply apparatus 1 according to the fourth embodiment, the melting step, the stirring step, and the like, as in the case of the first embodiment described above, The molding process is executed. In the stirring step, the molten glass rotates while flowing inside the first stirring tank K1 downward from above and while flowing inside the second stirring tank K2 upward from below. Stirring is performed by the stirring means S1 and the second stirring means S2.

  FIG. 8 shows the result of the simulation experiment on the mode of the molten glass flowing while receiving the stirring action by the first and second stirring means S1 and S2 in the first and second stirring tanks K1 and K2 as described above. FIG. The path indicated by the alternate long and short dash line with the symbol G in the same figure is the path through which the molten glass existing in the upper part of the clarification passage 10, that is, the molten glass containing the heterogeneous phase suspended in the surface portion of the melting furnace 2 and clarification tank 5 The path indicated by the broken line with the symbol H in the same figure was sunk in the molten glass existing in the lower part of the clarification passage 10, that is, the bottom of the melting furnace 2 and the clarification tank 5. The path | route through which the molten glass containing a heterogeneous phase flows is represented typically.

  As can be seen from the figure, the molten glass present in the upper part of the clarification passage 10 first flows into the first stirring tank K1 from the upper part of the first inlet M1 and flows downward in the central part thereof. , Flows out from the lower part of the first outlet N1, flows in the vicinity of the lower surface of the fourth communication path R4 in a substantially horizontal direction, and then flows into the second stirring tank K2 from the lower part of the second inlet M2 After flowing upward through the part, it flows out from the upper part of the second outlet N2 and flows in the vicinity of the upper surface part of the cooling passage 7. On the other hand, after the molten glass existing in the lower part of the clarification passage 10 first flows into the first stirring tank K1 from the lower part of the first inlet M1, and flows downward in the vicinity of the inner peripheral surface thereof, It flows out from the upper part of the first outlet N1, flows in the vicinity of the upper surface of the fourth communication path R4 in a substantially horizontal direction, and then flows into the second stirring tank K2 from the upper part of the second inlet M2, and its inner periphery. After flowing upward in the vicinity of the surface, it flows out from the lower portion of the second outlet N2 and flows in the vicinity of the lower surface portion of the cooling passage 7.

  In this case, while the molten glass existing in the upper part of the clarification passage 10 flows along the path indicated by the symbol G (path indicated by the alternate long and short dash line), the molten glass is inside the first stirring tank K1 and the second stirring tank K2. The molten glass that is present in the lower part of the clarification passage 10 is in contact with the rotating first stirring means S1 and the second stirring means S2 and receives a sufficient stirring action. Since it does not contact the first stirring means S1 and the second stirring means S1, S2 during the flow along the path indicated by Therefore, when the heterogeneous phase having a small specific gravity present on the surface portion of the molten glass in the melting furnace 2 and the refining tank 5 is particularly problematic, the heterogeneous phase on the surface portion of the first and second stirring tanks K1 and K2 The surface portion of the molten glass becomes sufficiently homogeneous by being sufficiently stirred inside and disappearing.

  FIG. 9 is a schematic front view showing the main part of the molten glass supply apparatus according to the fifth embodiment of the present invention. The molten glass supply apparatus 1 according to the fifth embodiment differs from the molten glass supply apparatus 1 according to the fourth embodiment described above in the middle of the supply flow path 4 in the first stirring tank K1 and the first stirring tank K1. In addition to the two stirring tanks K2, a third stirring tank K3 having the same or substantially the same size, shape and internal structure as those tanks K1, K2 is disposed on the downstream side of the third stirring tank K3. This is the point where the cooling passage 7 is communicated with the downstream side. Specifically, the upper part of the second stirring tank K2 (upper end of the peripheral wall) and the upper part of the third stirring tank K3 (upper end of the peripheral wall) are connected via the fifth communication path R5, and the third stirring tank A cooling passage 7 is connected to the lower part of K3 (the lower end of the peripheral wall). Therefore, the molten glass that has flowed out through the second outlet N2 of the second stirring tank K2 flows through the fifth communication path R5 in a substantially horizontal direction and then passes from the fifth communication path R5 to the upper part of the third stirring tank K3. After flowing into the inside through the formed third inlet M3 and flowing downward in the third stirring tank K3, the cooling passage is passed through the third outlet N3 formed in the lower part of the third stirring tank K3. 7 will flow out.

  In the case of producing a plate glass as a glass molded product using the molten glass supply apparatus 1 according to the fifth embodiment, as in the case of the above-described fourth embodiment, the melting step, the stirring step, The molding process is executed. In addition, in the stirring step, the molten glass is added to the third stirring tank K1 while flowing from the upper side to the lower side and while flowing inside the second stirring tank K2 from the lower side to the upper side. While flowing in the stirring tank K3 from above to below, stirring is performed by the rotating first, second, and third stirring means S1, S2, and S3. Then, referring to the result of the simulation experiment shown in FIG. 8, the flow of molten glass inside the third stirring tank K3 is substantially the same as the inside of the first stirring tank K1. Accordingly, when compared with the case of the above-described fourth embodiment, when the heterogeneous phase of the surface portion of the molten glass in the melting furnace 2 and the clarification tank 5 is particularly problematic, the stirring action and thus the homogenizing action on this heterogeneous phase. Can be expected to be performed more accurately.

  FIG. 10: is a schematic front view which shows the principal part of the molten glass supply apparatus which concerns on 6th Embodiment of this invention. The molten glass supply apparatus 1 according to the sixth embodiment differs from the molten glass supply apparatus 1 according to the fifth embodiment described above in the middle of the supply flow path 4 in the first, second, and second. In addition to the three stirring tanks K1, K2, and K3, a fourth stirring tank K4 having the same or substantially the same size, shape, and internal structure as those tanks K1, K2, and K3 is disposed on the downstream side thereof. The cooling passage 7 is communicated with the downstream side of the fourth stirring tank K4. Specifically, the lower part of the third stirring tank K3 (lower end of the peripheral wall) and the lower part of the fourth stirring tank K4 (lower end of the peripheral wall) are connected via the sixth communication path R6, and the fourth stirring tank A cooling passage 7 is connected to the upper portion of K4 (the upper end portion of the peripheral wall). Therefore, the molten glass that has flowed out through the third outlet N3 of the third stirring tank K3 flows through the sixth communication path R6 in a substantially horizontal direction and then passes through the sixth communication path R6 to the lower part of the fourth stirring tank K4. After flowing into the inside through the fourth inlet M4 and flowing upward in the fourth stirring tank K4, it flows out into the cooling passage 7 through the fourth outlet N4 at the upper part of the fourth stirring tank K4. It has become.

  In the case of producing a plate glass as a glass molded product using the molten glass supply apparatus 1 according to the sixth embodiment, as in the case of the first embodiment described above, the melting step, the stirring step, The molding process is executed. In the stirring step, the molten glass flows from the top to the bottom in the first stirring tank K1, while flowing from the bottom to the top in the second stirring tank K2, and the third stirring tank K3. The first, second, third, and fourth stirring means S1 that rotate while flowing through the inside of the fourth stirring tank K4 from the bottom to the top, Stir by S2, S3, S4. Then, referring to the result of the simulation experiment shown in FIG. 8 described above, the form of the flow of the molten glass inside the fourth stirring tank K4 is substantially the same as the inside of the second stirring tank K2. Therefore, even when compared with the case of the fifth embodiment described above, when the heterogeneous phase of the surface portion of the molten glass in the melting furnace 2 and the clarification tank 5 becomes a particular problem, the stirring action on the heterogeneous phase and thus homogenization are performed. It can be expected that the action is performed more accurately.

  FIG. 11: is a schematic front view which shows the principal part of the molten glass supply apparatus which concerns on 7th Embodiment of this invention. The molten glass supply apparatus 1 according to the seventh embodiment includes a communication configuration of the two stirring tanks K1 and K2 in the first embodiment and a communication configuration of the two stirring tanks K1 and K2 in the fourth embodiment. Is equivalent to a combination of That is, in order from the upstream side of the supply flow path 4, the clarification passage 10 is connected to the first inlet M1 at the top of the first stirring tank K1, and the first outlet N1 and the second stirring at the lower part of the first stirring tank K1. The second inlet M2 at the upper part of the tank K2 is connected via the first communication path R1, and the second inlet N2 at the lower part of the second stirring tank K2 and the third inlet M3 at the upper part of the third stirring tank K3. Are connected via the second communication path R2, and the third outlet N3 at the lower part of the third stirring tank K3 and the fourth inlet M4 at the lower part of the fourth stirring tank K4 are connected via the third communication path R3. The cooling passage 7 is connected to the fourth outlet N4 at the top of the fourth stirring tank K4.

  Even in the case of producing a plate glass as a glass molded product using the molten glass supply apparatus 1 according to the seventh embodiment, as in the case of the first embodiment described above, a melting step, a stirring step, The molding process is executed. In the stirring step, the molten glass flows in the first, second, and third stirring tanks K1, K2, and K3 from above to below, and in the fourth stirring tank K4 from below to above. While flowing in the direction, the first, second, third, and fourth stirring means S1, S2, S3, and S4 are stirred. Accordingly, in this case, not only the heterogeneous phase on the surface portion of the molten glass in the melting furnace 2 and the clarification tank 5 but also the agitating action and the homogenizing action are accurately performed not only on the heterogeneous phase on the bottom face portion. I can expect that.

  FIG. 12: is a schematic front view which shows the principal part of the molten glass supply apparatus which concerns on 8th Embodiment of this invention. The molten glass supply apparatus 1 according to the eighth embodiment differs from the molten glass supply apparatus 1 according to the first embodiment described above in that the molten glass in the first stirring tank K1 and the second stirring tank K2 The passage configuration is changed so that the flow direction is from the bottom to the top. That is, in order from the upstream side of the supply flow path 4, the clarification passage 10 is connected to the first inlet M1 formed in the lower part of the first stirring tank K1, and the first outlet N1 formed in the upper part of the first stirring tank K1. And the second inlet M2 formed in the lower part of the second stirring tank K2 are connected via the first communication path R1, and the cooling passage 7 is connected to the second outlet N2 formed in the upper part of the second stirring tank K2. It is a thing.

  In the case of producing a plate glass as a glass molded product using the molten glass supply apparatus 1 according to the eighth embodiment, the melting step, the stirring step, and the like, as in the case of the first embodiment described above, The molding process is executed. In the stirring step, the molten glass is stirred by the first and second stirring means S1 and S2 that rotate while flowing inside the first and second stirring tanks K1 and K2 from the lower side to the upper side. Is done. Therefore, also with such a configuration, as in the case of the first embodiment described above, the two kinds of heterogeneity of the heterogeneous phase on the surface portion and the heterogeneous phase on the bottom surface portion of the molten glass in the melting furnace 2 and the refining tank 5 are obtained. It can be expected that the agitation action and thus the homogenization action can be accurately performed on the phases. In addition, in the same mode as the communication configuration of the first and second stirring tanks K1 and K2 in the eighth embodiment, the third stirring tank is added and communicated, and further the fourth stirring tank is added and communicated. Alternatively, the communication configuration of the two agitation tanks K1 and K2 in the eighth embodiment and the communication configuration of the two agitation tanks K1 and K2 in the first embodiment described above or the two agitations in the fourth embodiment You may make it combine with the communication structure of the tanks K1 and K2.

  FIG. 13 is a graph showing the stirring efficiency when the number of stirring tanks is 2 to 4 in the above embodiment (first to third embodiments). Here, the stirring efficiency refers to the stirring means (each stirrer) that rotates the flow rate (kg / h) of the molten glass per unit time flowing through the supply channel (inside each stirring tank) within each stirring tank. The value is divided by the average number of revolutions (rpm). Therefore, this agitation efficiency is a measure for grasping the flow rate of the molten glass that can receive the agitation action (homogenization action) when each agitation means rotates once in each agitation tank. A characteristic curve J indicated by a solid line in the figure represents a change in actual stirring efficiency with respect to the number of stirring tanks, whereas a straight line K indicated by a broken line in the figure is proportional to the number of stirring tanks. This represents a state when the stirring efficiency is assumed to increase. As can be understood from the characteristic curve J in the figure, the actual stirring efficiency in the case of two stirring tanks is about three times that in the case of one, and the actual stirring efficiency in the case of three stirring tanks is The actual stirring efficiency when the number of stirring tanks is four is about 10 times or 11 times that when the number of stirring tanks is four. Thus, the stirring efficiency does not increase in proportion to the number of stirring tanks, but increases at a larger ratio, so the number of stirring tanks is set to 2 to 4 as in the above embodiments. If it is made into individual pieces, it becomes possible to efficiently stir and homogenize the molten glass.

  FIG. 14 is a graph showing the number of rotations required for homogenization when the number of stirring tanks is 2 to 4 in the above embodiment (first to third embodiments). Here, the rotation speed required for homogenization means that when the molten glass having a flow rate of 1 ton / h is to be flowed, the stirring means (stirrer) of the stirring tank is sufficiently stirred without any unreasonable resistance ( This means the number of rotations (rpm) of the stirring means required for homogenization. In addition, the rotation speed of the stirring means here is the total value of the rotation speed of each stirring means of each stirring tank. The characteristic curve L shown in the figure represents the relationship between the number of stirring tanks and the number of rotations required for homogenization. As is apparent from this characteristic curve L, as the number of stirring tanks increases, the number of rotations required for homogenization decreases, and the number of rotations of each stirring means can be significantly reduced. Therefore, if the number of stirring tanks is 2 to 4 as in each of the above-described embodiments, unreasonable resistance does not act on the stirring means of each stirring tank, and the stirring blades are scraped off as platinum foreign matter in the molten glass. It becomes difficult to cause a problem of being mixed in.

  Moreover, in the above embodiment, since 2 to 4 stirring tanks are arranged adjacent to each other in the upstream and downstream directions in an independent state, each stirring tank can be handled in an independent state, Maintenance and inspection, repair or replacement can be facilitated and simplified, and the temperature of the agitation tank can be adjusted to make the resistance acting on the agitation means from molten glass appropriate. It becomes difficult, and it becomes possible to adjust the temperature of the molten glass flowing through each stirring vessel, and thus the viscosity, easily and appropriately.

  The molten glass supply apparatus according to the above embodiment can be effectively applied when forming a glass sheet used for a glass panel for a liquid crystal display by an overflow downdraw method, but the forming method is other than this. As for glass molded products, glass panels for other flat displays such as electroluminescence displays and plasma displays, charge coupled devices (CCD), equal-magnification proximity solid-state imaging devices (CIS), CMOS The present invention can also be applied to forming various types of image sensors such as image sensors, cover glasses such as laser diodes, and plate glass used for glass substrates of hard disks and filters.

  In the above embodiment, 2 to 4 stirring tanks are arranged adjacent to each other in the upstream / downstream direction in the middle of the supply flow path, but 5 or more stirring tanks are arranged adjacent to each other in the upstream / downstream direction. May be. Specifically, five or more agitation tanks may be provided only in the communication configuration shown in FIG. 1, FIG. 4, or FIG. 5, and more than five in the communication configuration shown in FIG. 6, FIG. 9, or FIG. A stirring tank may be provided, or two or more kinds of communication structures shown in FIG. 11 and a communication structure shown in FIG. 12 may be arbitrarily selected and combined to provide five or more stirring tanks. In this case, it is preferable that the number of the stirring tanks is at least 2, at least 3, at least 4, and further at least 5 in accordance with the flow rate of the molten glass flowing through the supply channel.

DESCRIPTION OF SYMBOLS 1 Molten glass supply apparatus 2 Molten kiln 3 Molding apparatus 4 Supply flow path K1 1st stirring tank K2 2nd stirring tank K3 3rd stirring tank K4 4th stirring tank M1 1st inlet M2 2nd inlet M3 3rd inlet M4 fourth inlet S1 stirring blade (first stirring means)
S2 stirring blade (second stirring means)
S3 stirring blade (third stirring means)
S4 stirring blade (fourth stirring means)

Claims (6)

In a molten glass supply apparatus comprising a melting furnace serving as a supply source of molten glass and a supply flow path for supplying molten glass flowing out of the melting furnace to a molding apparatus,
The molten glass has a characteristic that a temperature corresponding to a viscosity of 1000 poise is 1350 ° C. or more, and a plurality of stirring tanks that are individually independent are arranged in the upstream and downstream directions in the middle of the supply flow path. The plurality of stirring tanks each include a peripheral wall portion and a bottom wall portion whose inner peripheral surfaces are cylindrical surfaces, and an inlet and an outlet for molten glass are formed on the peripheral wall portions, respectively. , One inflow port and the other outflow port of the adjacent stirring tanks are connected via a communication path, and the height position of the vertical direction end of the stirring blade accommodated in the inside of each of the mixing tanks A molten glass supply device, which exists between an opening upper end position and an opening lower end position of an inflow port.   Regarding the adjacent stirring tanks in the plurality of stirring tanks, an inlet is formed in one of the upper peripheral wall part or the lower peripheral wall part of the upstream stirring tank, and an outlet is formed in the other. An inflow port and an outflow port are formed so that the upper and lower portions are the same as the inflow port and the outflow port of the upstream stirring tank, and the upper and lower portions of the upstream stirring tank and the outflow port are opposite to each other. The molten glass supply apparatus according to claim 1, wherein the inlet of the downstream stirring tank is connected via a communication path.   Regarding the adjacent stirring tanks in the plurality of stirring tanks, an inlet is formed in one of the upper peripheral wall part or the lower peripheral wall part of the upstream stirring tank, and an outlet is formed in the other. An inflow port and an outflow port are respectively formed upside down with respect to the inflow port and the outflow port of the upstream stirring tank, and the upper and lower portions of the outflow port of the upstream stirring tank and the outflow port have upper and lower parts. The molten glass supply apparatus according to claim 1 or 2, wherein the same inlet of a downstream agitation tank is connected via a communication path.   The molten glass supply device according to any one of claims 1 to 3, wherein all of the plurality of stirring tanks are configured to perform a homogenizing action.   The molten glass supply apparatus according to any one of claims 1 to 3, wherein an outer peripheral end of a stirring blade accommodated in the stirring tank is close to the inner peripheral surface.   The molten glass has a melting step for melting high-viscosity glass having a characteristic corresponding to a viscosity of 1000 poise of 1350 ° C. or more in a melting furnace, and a supply flow path from the melting furnace to a molding apparatus on the downstream side. When flowing, an agitation step for allowing the molten glass to flow into and through an agitation tank arrangement part in the middle of a supply flow path in which a plurality of agitation tanks that are individually independent are arranged adjacent to each other on the upstream and downstream sides And a molding step of forming the glass molded product by supplying the molten glass stirred in the stirring step to a molding device. In the stirring step, the plurality of stirring tanks each have an inner peripheral surface of a cylindrical surface. The peripheral wall portion and the bottom wall portion are formed, and an inlet and an outlet for molten glass are formed on each of the peripheral walls, and one inlet and the other outlet of the adjacent stirring tanks are formed. Via the passage The plurality of agitation blades in a state where the height positions of the vertical ends of the stirring blades that are connected to each other and are located between the opening upper end position and the opening lower end position of each of the inlets. A method for producing a glass molded product, wherein molten glass flows into and out of a tank.

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