WO2006059575A1

WO2006059575A1 - Glass production apparatus and process for producing glass

Info

Publication number: WO2006059575A1
Application number: PCT/JP2005/021813
Authority: WO
Inventors: Akihiro Koyama; Junji Kurachi; Hiromitsu Seto; Kazuhiro Yamamoto; Daisuke Miyabe; Yutaka Senshu
Original assignee: Nippon Sheet Glass Company, Limited
Priority date: 2004-12-01
Filing date: 2005-11-28
Publication date: 2006-06-08

Abstract

A glass production apparatus making use of vacuum clarification technique; and a relevant process for producing glass. There is provided a glass production apparatus that without relying on stirrers and screws only, is capable of enhancing of air bubble removing efficiency through, for example, reduction of any vertical interval between melting unit and vacuum clarification unit, homogenization of molten glass and/or air bubble generation, and provided a process for producing glass with the use of the apparatus. In particular, there is provided a glass production apparatus comprising a melting unit capable of melting a glass raw material into a molten glass; a vacuum clarification unit capable of transferring the molten glass via piping and reducing any air bubbles trapped in the transferred molten glass in vacuum atmosphere; and a molding unit capable of molding the molten glass having any air bubbles reduced, wherein a barrier for changing the flow of molten glass is disposed in a flow channel of molten glass up to reaching of air bubbles to a flux line of molten glass in the vacuum clarification unit and is supported by at least one member selected from among the melting unit, the piping and the vacuum clarification unit.

Description

Specification

Glass manufacturing apparatus and glass manufacturing method

Technical field

TECHNICAL FIELD [0001] The present invention relates to a glass manufacturing apparatus and a glass manufacturing method using a vacuum clarification method for reducing bubbles contained in a molten glass under a reduced pressure atmosphere.

Background art

[0002] Generally, glass is formed by melting a glass raw material into a molten glass (melting process), and reducing the compositional deviation in the molten glass as necessary (homogenization process) (molding process). Become a product. Usually, in molten glass, there are innumerable bubbles formed by chemical decomposition of raw materials. Such bubbles may affect the optical properties of the product after molding. In particular, glass or the like used for a display substrate is required to be substantially free of bubbles that affect the properties of the substrate. For this reason, the process of reducing bubbles in glass melt (clarification process) is very important in the glass manufacturing process.

[0003] Conventionally, a vacuum clarification method is known as one of the clarification methods! In the vacuum clarification method, molten glass is introduced into the vacuum clarification part in a reduced pressure atmosphere from the molten part to reduce bubbles contained in the molten glass. Examples of a glass production apparatus using a vacuum clarification method are disclosed in, for example, Japanese Patent Laid-Open Nos. 5-58646 and 5-208830.

[0004] In the glass manufacturing apparatus disclosed in Japanese Patent Application Laid-Open No. 5-58646, a decompression treatment tank, which is a depressurization and clarification section, is arranged at a higher position than a melting tank, which is a melting section, and both tanks use risers. Connected. In the glass manufacturing apparatus disclosed in Japanese Patent Laid-Open No. 5-208830, a screw is placed in the riser pipe, and pressure is applied in the direction in which the molten glass is pushed back to the molten part. The height difference between the melting part and the vacuum clarification part provided in the production apparatus of the publication is reduced. In addition, a stirrer is arranged in the flow path of the molten glass, and the efficiency of removing the bubbles by homogenizing the molten glass and generating bubbles by stirring the molten glass is achieved.

[0005] However, the glass manufacturing apparatus disclosed in Japanese Patent Laid-Open No. 5-208830 has the above-described height difference. To reduce the difference in height, such as using a screw to reduce the glass, and using a stirrer to generate bubbles in the molten glass, rotation is performed in order to reduce the height difference and to generate molten glass and Z or bubbles. It is the structure which uses only the stirring mechanism which has a part. With such a configuration, there is a problem in the durability of the apparatus that places a large load on the stirring mechanism. In addition, while the screw stirrer is rotating, it may come into contact with the riser or the inner wall of the vacuum clarification tank (vacuum defoaming tank), causing damage to the production equipment or contamination.

Disclosure of the invention

[0006] The glass manufacturing apparatus of the present invention includes a melting part that melts a glass raw material to form a molten glass, the molten glass is transferred via a pipe, and bubbles contained in the transferred molten glass are reduced in a reduced-pressure atmosphere. The glass manufacturing apparatus includes a vacuum clarification part (vacuum degassing part) to be reduced in step 1 and a molding part for molding the molten glass in which the bubbles are reduced, and a barrier for changing the flow of the molten glass. In the reduced pressure clarification part, the bubbles are disposed in the flow path of the molten glass until the bubbles reach the ground surface of the molten glass, and the barrier is selected from the molten part, the pipe, and the reduced pressure clarification part. Supported by at least one.

[0007] The method for producing glass of the present invention includes a melting step in which a glass raw material is melted in a melting part to form a molten glass, and the molten glass is transferred to a reduced pressure clarification part in a reduced pressure atmosphere via a pipe. A method for producing glass, comprising a reduced-pressure clarification step (vacuum defoaming step) for reducing bubbles contained in the molten glass at a reduced-pressure clarification portion and a molding step for forming the molten glass with reduced bubbles. The flow of the molten glass is changed by arranging a barrier in the flow path of the molten glass. The barrier is disposed in the flow path until the bubbles reach the ground surface of the molten glass in the vacuum clarification unit, and at least one selected from the melting unit, the pipe, and the vacuum clarification unit. It is supported by one.

[0008] In the present invention, the flow of the molten glass is changed by the rear supported by at least one of the melting part, the piping, and the reduced pressure clarification part force. For this reason, for example, pressure loss can be generated without relying only on the screw, and for example, the difference in height between the melting part and the reduced pressure clarification part in the glass manufacturing apparatus can be reduced. For example, stirrer The molten glass can be mixed without relying on only one, and for example, the compositional deviation of the molten glass can be reduced. Furthermore, compared with the case where the stirring mechanism which has a rotation part like a screw and a stirrer is used, mixing of the foreign material to molten glass can be suppressed.

Brief Description of Drawings

FIG. 1 is a schematic view showing an example of a glass manufacturing apparatus of the present invention.

FIG. 2A is a schematic diagram showing an example of a static mixer used as a rear in the glass manufacturing apparatus of the present invention.

FIG. 2B is a schematic diagram showing an example of an element of a static mixer used as a rear in the glass manufacturing apparatus of the present invention.

FIG. 3 is a schematic view showing another example of the glass manufacturing apparatus of the present invention.

FIG. 4 is a schematic view showing still another example of the glass manufacturing apparatus of the present invention.

FIG. 5 is a schematic view showing an example of a barrier in the glass manufacturing apparatus of the present invention.

FIG. 6 is a schematic view showing still another example of the glass manufacturing apparatus of the present invention.

FIG. 7 is a schematic view showing another example of the glass manufacturing apparatus of the present invention different from the above.

FIG. 8 is a schematic view showing an example different from the above of the glass manufacturing apparatus of the present invention.

FIG. 9 is a schematic view showing an example different from the above of the glass manufacturing apparatus of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are assigned to the same members, and duplicate descriptions may be omitted.

[0011] First, the glass manufacturing apparatus of the present invention will be described.

[0012] A glass manufacturing apparatus 1 shown in FIG. 1 includes a melting part (melting tank 2) that melts a glass raw material to form a molten glass 4, and a vacuum clarification part that reduces bubbles contained in the molten glass 4 in a reduced-pressure atmosphere. (A vacuum clarification tank 3 and a chamber 31) and a molding part 12 for molding the molten glass 4 in which bubbles are reduced. The molten glass 4 is transferred to the vacuum clarification tank 3 through a pipe 6 disposed between the melting tank 2 and the vacuum clarification tank 3. Inside the pipe 6, a static mixer element 5 (hereinafter also simply referred to as “element 5”) is arranged as a noria for changing the flow of the molten glass 4. The element 5 is supported by the pipe 6 and constitutes a static mixer together with the pipe 6. In the vacuum clarification tank 3, the molten gas with reduced air bubbles The lath 4 is supplied to the forming unit 12 through the adjustment tank 11.

[0013] The element 5 can play the same role as a screw or stirrer in the flow path of the molten glass. For example, depending on the shape and arrangement method of the element 5, the element 5 becomes a flow path resistance against the flow of the molten glass 4, and pressure loss can be generated in the region of the pipe 6 where the element 5 is arranged. There is a pressure difference between the melting tank 2 and the vacuum clarification tank 3. The above pressure loss can reduce the height difference to be provided between the melting tank 2 and the vacuum clarification tank 3. By selecting the shape and arrangement method of the element 5 in more detail, the above height difference can be almost eliminated. For example, in the example shown in FIG. 1, the ground surface of the molten glass 4 in the melting tank 2 and the ground surface of the molten glass 4 in the vacuum clarification tank 3 are substantially at the same height, and the molten glass 4 is in the horizontal direction. Be transported. Such a glass manufacturing apparatus can be made smaller than the glass manufacturing apparatus disclosed in Japanese Patent Laid-Open No. 5-58646. However, as long as the molten glass 4 can be transferred from the melting tank 2 to the vacuum clarification tank 3, a height difference may be provided between both tanks.

[0014] For example, depending on the shape and arrangement method of the element 5, bubbles can be generated in the molten glass 4 flowing in the flow path. When bubbles are generated appropriately, bubbles can be reduced more efficiently in the vacuum clarification tank 3.

[0015] The element 5 does not require a drive unit required for a screw or a stirrer, and the drive unit is disposed outside the flow path of the molten glass 4 or the chamber 31 and is connected to the drive unit. Does not need to be formed on the flow path and the wall of Z or chamber 31. For this reason, the flow path of the molten glass 4 can be substantially sealed, and for example, the pressure fluctuation in the vacuum clarification tank 3 and the mixing of foreign matters into the vacuum clarification tank 3 can be suppressed. The element 5 is fixed inside the pipe 6 (that is, in the flow path of the molten glass 4), and does not actively operate by the power of external force. For this reason, it is possible to suppress damage to the equipment due to damage to the inner wall and rotating part of the pipe 6 and the resulting contamination of the molten glass 4, and it is more durable than stirrers and screws. . That is, by using the glass manufacturing apparatus of the present invention, it becomes easy to continuously manufacture glass with stable quality. Particularly effective when glass contains a highly volatile substance (for example, diboron trioxide (B 2 O 3)) as a component.

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large. High volatility substances are likely to change volatility due to pressure fluctuations in the vacuum clarification tank 3. In addition, when a through-hole is formed in the wall surface of the flow path, a volatilized substance accumulates in the vicinity of the through-hole and may cause contamination.

FIG. 2A shows an example of the arrangement of the elements 5 in the pipe 6. In the example shown in FIG. 2A, a plurality of elements 5 are arranged in the pipe 6 (more specifically, two kinds of elements 21 and 22 are alternately connected). 5 (elements 21 and 22) is supported by the inner wall of the pipe 6 through the blanket 23 and fixed to the pipe 6. Further, a static mixer 20 is configured by the pipe 6 and the element 5 arranged in the pipe 6.

[0017] The elements 21 and 22 are norias having a structure in which the molten glass flowing in the pipe 6 is rotated in the opposite directions (clockwise or clockwise with respect to the traveling direction of the molten glass, respectively). (See arrow in Figure 2A). In addition, the elements 21 and 22 are arranged so that the phases thereof are different from each other by 90 ° at the connection surface between the elements when viewed in the traveling direction of the molten glass.

[0018] The position where the element 5 is arranged is not limited to the inside of the pipe 6 connecting the melting tank 2 and the vacuum clarification tank 3, but until the bubbles reach the ground surface of the molten glass 4 in the vacuum clarification tank 3. It only has to be arranged in the flow path of the molten glass 4. For example, as shown in FIG. 3, the element 5 may be disposed in the flow path 8 of the molten glass provided in the vacuum clarification clarification tank 3. The flow path 8 in FIG. 3 is located until the bubbles 7 reach the ground surface of the molten glass 4. Further, as shown in FIG. 4, the element 5 may be disposed in the flow path 8 of the molten glass 4 provided inside the melting tank 2. When element 5 is placed in pipe 6, optimization and maintenance of the shape and arrangement of element 5 are easy. A plurality of elements 5 may be arranged dispersed in a plurality of regions. For example, the element 5 is divided into an upstream side (melting tank 2 side) and a downstream side (vacuum clarification tank 3 side) of the pipe 6. May be arranged.

[0019] The element 5 as a barrier may be supported by at least one selected from the melting tank 2, the pipe 6, and the vacuum clarification section (the vacuum clarification tank 3 and the chamber 31) force. The method and structure for supporting the element 5 are not particularly limited. For example, as shown in FIG. 2A, the element 5 may be supported by a blanket 23 fixed to the inner wall of the pipe 6, or the pipe 6 or the chamber 31 may be supported. It may be supported by a member that penetrates the wall surface. Supported by a member that penetrates the wall Even in this case, unlike the case where the drive shaft of the screw or stirrer is passed through, the space between the wall surface and the member can be sealed, so that the flow path of the molten glass 4 can be substantially sealed. From the viewpoint of ensuring the sealing more reliably, it is preferable that the element 5 is supported by at least one inner wall selected from the melting tank 2, the pipe 6, and the vacuum clarification section as in the example using the blanket 23. ,.

[0020] The specific structure of the element 5 is not particularly limited. If the shape and arrangement of element 5 are arbitrarily set according to the characteristics required for element 5.

The material used for the element 5 is not particularly limited as long as it has heat resistance and resistance to the molten glass 4. For example, a metal having heat resistance and corrosion resistance to the molten glass 4 may be used. Specifically, for example, it is sufficient to use a metal or alloy having a melting point of 1700 ° C or higher. More specifically, platinum, tungsten, molybdenum, iridium, or an alloy containing these metals, or An alloy containing these metals and rhodium may be used.

[0022] The viscosity of the molten glass 4 flowing in the region where the element 5 is disposed may be in the range of, for example, 100 d-Pa-sec (poise) to: L 0 ⁴ d · Pa · sec (poise). 100d − Pa − sec (poise) ˜: L 0 ³ d · P a ′ sec (poise) is preferable. Since element 5 has a lower load than a screw or stirrer, the temperature range of molten glass 4 flowing in the flow path can be set wider.

[0023] When a plurality of elements 5 are arranged, the number of the elements 5 is not particularly limited, the required pressure loss, the viscosity, density, flow rate, Reynolds of the molten glass 4 flowing in the area where the elements 5 are arranged. It may be determined according to the number. For example, the range of 4 to 36 including the two types of elements 21 and 22 is preferable. In general, the length of the element 5 is 1.5 times the element diameter a (1.5a), as shown in FIG. 2B.

The noria in the glass manufacturing apparatus 1 of the present invention is not limited to the form shown in FIG. It is arranged in the flow path of the molten glass 4 until the bubbles reach the ground surface of the molten glass 4 in the pressure reducing clarification tank 3, and is supported by at least one selected from the melting tank 2, the pipe 6, and the vacuum clarification force. As long as the flow of the molten glass 4 can be changed, the structure and configuration of the barrier are not particularly limited. For example, a plate-like barrier 24 disposed inside the pipe 6 as shown in FIG. 5 may be used. In addition, the materials used for Noria, The viscosity and temperature of the molten glass 4 that flows through the region where the a is placed are the same as in the case of the static mixer element 5.

[0025] The number of barriers disposed in the flow path of the molten glass is not particularly limited, and a single barrier may be disposed, or two or more barriers may be disposed as shown in FIG. 2A and FIG. Also good. Among these, it is preferable to arrange two or more nozzles. For example, the pressure loss value generated in the barrier can be optimized and the generation of bubbles can be controlled more easily. When two or more barriers are arranged, the arrangement method of the noria is not particularly limited, and may be arbitrarily arranged according to the characteristics required for the noria. In particular, as shown in FIG. 2A and FIG. 5, it is preferable that the flow paths overlap with each other when viewed in the direction of progress of the molten glass. With such an arrangement method, for example, the control range of the pressure loss value and the amount of generated bubbles can be made wider. Note that “overlapping each other” means that at least a part of the barrier overlaps, and “the direction of molten glass travel” means that the molten glass travels through the flow path when the barrier is removed. It is for the direction.

When the static mixer element 5 is used as the noria, the molten glass 4 can be mixed in the flow path to reduce the compositional deviation of the molten glass 4. For this reason, depending on the shape and arrangement method of the element 5, it is possible to more efficiently reduce bubbles in the vacuum clarification tank 3, and to simplify the homogenization process when homogenization is performed after vacuum clarification. .

[0027] The barrier may have a movable part as long as it operates passively according to the flow of the molten glass 4 or the like, which is not necessarily fixed to the flow path.

[0028] The structure, configuration and the like of the melting tank 2 are not particularly limited as long as the glass raw material can be melted by heating, and may be the same structure and structure as those of a melting tank generally used as a glass manufacturing apparatus.

[0029] The structure and configuration of the vacuum clarification section are not particularly limited as long as the inside of the vacuum clarification tank 3 can be maintained in a reduced pressure atmosphere, and has the same structure and configuration as the vacuum clarification section generally used as a glass manufacturing apparatus. I just need it. In the examples shown in FIGS. 1, 3 to 4 and the following FIGS. 6 to 9, the vacuum clarification tank 3 is accommodated in a chamber 31 having a strength that can withstand a reduced pressure atmosphere, and the pressure reduction mechanism 32 is provided in the chamber 31. By connecting, the inside of the vacuum clarification tank 3 is maintained in a vacuum atmosphere. For example, the decompression mechanism 32 may include an exhaust pump. [0030] The reduced-pressure clarification tank 3 includes, for example, a refractory brick! Do it! /. In particular, it is preferable that the inner wall of the vacuum clarification tank 3 is coated with a metal having heat resistance and corrosion resistance to molten glass. Specifically, the metal exemplified as the material used for the element 5 may be used. Since these metals have high resistance to molten glass, the durability of the production apparatus can be improved.

[0031] The pressure in the vacuum clarification tank 3 at the time of vacuum clarification is not particularly limited as long as vacuum clarification can be performed, and may be maintained in a range of, for example, 0.05 atm to 0.5 atm.

In the example shown in FIG. 1, the melting tank 2 is shown as the melting part, and the vacuum clarification tank 3 and the chamber 31 are shown as the vacuum clarification part. In the glass manufacturing apparatus of the present invention, the glass raw material is used. As long as it can be melted by heating, and the bubbles contained in the molten glass can be reduced in a reduced-pressure atmosphere, it can be a melting part and a reduced-pressure clarification part having an arbitrary structure and configuration, respectively.

[0033] The method for transferring the molten glass 4 to the vacuum clarification tank 3 is not particularly limited. For example, as shown in FIG. 1, the molten glass 4 may be introduced in the horizontal direction with respect to the ground surface of the molten glass 4 in the vacuum clarification tank 3. Moreover, as shown in FIG. 6, the molten glass 4 may be introduced from the upper part of the vacuum clarification tank 3, or as shown in FIG. 7, the molten glass 4 is introduced from the lower cover of the vacuum clarification tank 3. Also good. A similar effect can be obtained in each case. Note that the method of transferring the molten glass 4 from the vacuum clarification tank 3 to the adjustment tank 11 (the adjustment tank 11 can be omitted, and in that case, the molding unit 12 and the homogenization mechanism 13 described later) is particularly effective. Not limited! The flow rate adjusting mechanism (e.g., a plunger) is provided at the inlet and Z or outlet of each tank, such as the outlet to the piping 6 in the melting tank 2 and the outlet to the adjusting tank 11 in the vacuum clarification tank 3. ) May be arranged. By arranging the flow rate adjustment mechanism, conditions such as pressure in each tank can be made closer to the optimum values.

In the glass manufacturing apparatus 1 of the present invention, as shown in FIG. 8, a plurality of pipes 6 for transferring the molten glass 4 to the vacuum clarification tank 3 may be arranged. In the manufacturing apparatus 1 shown in FIG. 8, two pipes 6 are arranged in parallel, two in the vertical direction and two in the back of the two pipes 6 shown. When multiple pipes 6 are arranged, for example, by appropriately selecting the number of pipes 6 for transferring the molten glass 4, the flow rate control of the molten glass 4 transferred to the vacuum clarification tank 3 can be controlled. It can be carried out. In addition, since the inner diameter of each pipe 6 can be reduced, when the static mixer element 5 is arranged in the pipe 6, for example, the number of elements 5 required to obtain the same pressure loss can be reduced, and the length of the pipe 6 can be reduced. Can be shorter.

[0035] In the glass manufacturing apparatus 1 of the present invention, the pipe 6 may be configured with a member force capable of conducting heating. When the pipe 6 is energized and heated, the temperature of the molten glass 4 flowing in the pipe 6 can be adjusted, and the flow rate of the molten glass 4 transferred to the vacuum clarification tank 3 can be controlled. At this time, if the barrier is arranged in the pipe 6, the barrier itself is heated as the pipe 6 is energized and heated, so that the molten glass flowing in the pipe 6 is compared to the case where the noria is not arranged. 4 can be adjusted more easily. In particular, the effect is great when a noria composed of members that can be heated by electric current is disposed.

[0036] The structure and configuration of the adjusting tank 11 and the forming unit 12 are not particularly limited, and may be the same structure and configuration as the adjusting tank and the forming unit that are generally used as a glass manufacturing apparatus. As described above, the adjustment tank 11 can be omitted.

FIG. 9 shows another example of the glass manufacturing apparatus of the present invention. In the glass manufacturing apparatus 1 shown in FIG. 9, there is a homogenization mechanism 13 between the vacuum clarification tank 3 and the forming part 12 for reducing the compositional deviation of the molten glass 4 in which bubbles are reduced in the vacuum clarification tank 3. Has been placed. Such a manufacturing apparatus 1 can manufacture glass with reduced striae.

[0038] The structure, configuration and the like of the homogenization mechanism 13 are not particularly limited, and may be the same structure and configuration as those of a homogenization mechanism generally used as a glass manufacturing apparatus. For example, as shown in FIG. 9, a homogenization mechanism 13 having a stirring mechanism 14 such as a stirrer may be used.

[0039] Next, a method for producing the glass of the present invention will be described. The glass manufacturing method of the present invention can be carried out, for example, by the glass manufacturing apparatus of the present invention described above.

[0040] In the glass manufacturing method of the present invention, the flow of molten glass in the flow path is changed by disposing noria in the flow path for transferring the molten glass from the melting process to the vacuum clarification process. . Noria is arranged in the flow path of the molten glass until the bubbles reach the ground surface of the molten glass in the vacuum clarification part, and is supported by at least one selected from the melting part, the piping, and the vacuum clarification part force. ing. The barrier used in the manufacturing method of the present invention does not require a drive unit, and the drive unit is disposed outside the melting unit, piping, and vacuum clarification unit. There is no need to connect to the barrier. For this reason, piping and a reduced pressure clarification part can be sealed substantially, and the pressure fluctuation in a reduced pressure clarification process and the mixing of the foreign material to a molten glass can be suppressed. That is, by using the production method of the present invention, it becomes easy to continuously produce glass with stable quality.

[0041] Depending on the shape and arrangement method of the nozzle, pressure loss can be generated, bubbles can be generated in the molten glass, or the molten glass can be mixed. In the case of a barrier that generates a pressure loss, the difference in height between the melting part (for example, the melting tank) and the reduced pressure clarification part (for example, the reduced pressure clarification tank) can be reduced. By selecting the shape and arrangement method of the nozzles in more detail, it is possible to carry out both processes continuously without providing a height difference. In the case of a barrier that generates bubbles in the molten glass, the force depending on the amount of bubbles generated can reduce bubbles more efficiently in the vacuum clarification process. In the case of a barrier mixed with molten glass, the compositional deviation of the molten glass can be reduced. At this time, depending on the shape and arrangement method of the rear, it is possible to more efficiently reduce the bubbles in the vacuum clarification process, and when performing the homogenization process after the vacuum clarification process, Can be simplified. The specific structure and configuration of the barrier may be the same as those of the above-described Noria in the glass manufacturing apparatus of the present invention.

[0042] In the manufacturing method of the present invention, by selecting the shape and arrangement method of the barrier, the degree of load applied to the barrier structurally compared to the case of using a stirring mechanism such as a screw or a stirrer !, Therefore, the temperature range of the molten glass to be transferred can be set wider. Here, the method of transferring the molten glass to the melted part force reduced pressure clarified part is not particularly limited.

[0043] In the production method of the present invention, the viscosity of the molten glass flowing in the region where the barrier is disposed is, for example, in the range of lOOd 'Pa' sec (poise) to: L0 ⁴ d 'Pa' sec (poise) 100d

• Pa 'sec (poise) ~: The range of LO d · Pa · sec (poise) is preferred! / ヽ.

[0044] The conditions for the vacuum clarification are not particularly limited if a general method and apparatus are used in the vacuum clarification process. For example, the pressure in the vacuum clarification section may be in the range of about 0.05 atm to 0.5 atm.

[0045] The melting process and the molding process are not particularly limited, and are generally used for glass production. A method and an apparatus may be used. Specifically, it can be applied to various glass production methods such as a float method, a roll-out method, a Colburn method, and a fusion method.

[0046] In the production method of the present invention, a homogenization process for reducing the deviation in the composition of the molten glass after the reduction of bubbles in the vacuum clarification process is further performed between the vacuum clarification process and the molding process. May be included. Since the striae can be reduced by the homogenization process, glass with more stable quality can be obtained. The homogenization process is not particularly limited, and a general homogenization method and apparatus may be used. For example, the molten glass may be stirred using a stirring mechanism such as a stirrer to homogenize the molten glass.

[0047] The production method of the present invention can be applied regardless of the type of glass. In particular, application to glass containing diboron trioxide (B 2 O 3) is effective. Diboron trioxide is clarified under reduced pressure

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High volatility at the time. For this reason, the volatilization amount of nitrous acid triboron is easily affected by pressure fluctuations in the vacuum clarification section. When manufacturing glass, the raw material is melted in advance taking into consideration the volatilization amount of diboron trioxide. However, if the volatilization amount of boron trioxide is varied, the quality of the resulting glass will be reduced. It becomes difficult to keep it constant. In the production method of the present invention, the pressure fluctuation in the vacuum clarification part can be reduced, and the bubbles contained in the molten glass can be reduced more efficiently. Therefore, a highly volatile component such as triboron trioxide is used. In the case of producing a glass containing, for example, in the case of producing a glass containing 5 mol% or more of niobium trioxide, it becomes easier to produce a glass having a stable quality.

[0048] The present invention can be applied to other embodiments without departing from the intent and essential characteristics thereof. The embodiments disclosed in this specification are illustrative in all respects and are not limited thereto. The scope of the present invention is shown not by the above description but by the appended claims, and all modifications that are equivalent in meaning and scope to the claims are included therein.

Industrial applicability

[0049] According to the present invention, since the flow of the molten glass is changed by the noria supported by at least one selected from the melting part, the piping, and the vacuum clarification part, in the vacuum clarification of the molten glass, Rather than relying solely on a stirrer or screw, for example, reducing the height difference between the molten part and the vacuum clarified part, homogenizing the molten glass, and The efficiency of removing bubbles due to the generation can be improved.

The glass production apparatus and the glass production method of the present invention can be applied regardless of the type of glass, and in particular, can be applied to glass containing a highly volatile component (eg, niobium triacid). It is effective.

Claims

The scope of the claims

[1] a melting part that melts a glass raw material to form a molten glass;

The molten glass is transferred through a pipe, and a reduced pressure clarification unit that reduces bubbles contained in the transferred molten glass in a reduced pressure atmosphere,

A glass manufacturing apparatus comprising a molding unit for molding the molten glass with reduced bubbles.

A barrier that changes the flow of the molten glass is disposed in the flow path of the molten glass until the bubbles reach the ground surface of the molten glass after the reduced-pressure clarified portion.

The glass manufacturing apparatus, wherein the barrier is supported by at least one selected from the melting section, the pipe, and the vacuum clarification section.

[2] The glass manufacturing apparatus according to [1], wherein the barrier is disposed inside the pipe.

[3] The glass manufacturing apparatus according to claim 1, wherein two or more of the barriers are arranged.

[4] The glass manufacturing apparatus according to claim 3, wherein the two or more barriers are arranged so as to overlap each other when the flow path is viewed in the traveling direction of the molten glass.

5. The glass manufacturing apparatus according to claim 1, wherein the barrier is fixed with respect to the flow path.

6. The glass manufacturing apparatus according to claim 1, wherein the barrier is a static mixer element.

[7] Between the reduced pressure clarification part and the molding part,

The glass manufacturing apparatus according to claim 1, further comprising a homogenization mechanism that reduces a deviation in a composition of the molten glass in which the bubbles are reduced.

[8] a melting process in which a glass raw material is melted in the melting part to form a molten glass;

A vacuum clarification step of transferring the molten glass through a pipe to a vacuum clarification part in a reduced pressure atmosphere, and reducing bubbles contained in the molten glass in the vacuum clarification part;

A glass manufacturing method comprising a molding step of molding the molten glass with reduced bubbles,

The flow of the molten glass is changed by arranging a barrier in the flow path of the molten glass. Let

The barrier is disposed in the flow path until the bubble reaches the ground surface of the molten glass, and is selected from the molten part, the pipe, and the reduced pressure clarified part. A method for producing glass, wherein the glass is supported by at least one.

9. The glass manufacturing method according to claim 8, wherein the flow of the molten glass flowing through the pipe is changed by arranging the barrier inside the pipe.

10. The method for producing glass according to claim 8, wherein two or more barriers are arranged.

11. The glass manufacturing method according to claim 10, wherein the two or more barriers are arranged so as to overlap each other when the flow path is viewed in the traveling direction of the molten glass.

12. The glass manufacturing method according to claim 8, wherein the barrier is fixed to the flow path.

13. The method for producing glass according to claim 8, wherein the barrier is a static mixer element.

[14] Between the reduced pressure clarification step and the molding step,

9. The method for producing glass according to claim 8, further comprising a homogenization step of reducing the compositional deviation of the molten glass in which the bubbles are reduced.

15. The method for producing glass according to claim 8, wherein the glass contains diboron trioxide (B 2 O 3).