Apparatus for manufacturing glass articles, and method for manufacturing glass articles

Abstract

This technology provides a way to manufacture desired glass articles even if glass fragments resulting from a broken glass observation window fall inside a glass article molding apparatus. [Solution] A glass article manufacturing apparatus that melts glass raw materials to obtain molten glass, forms the molten glass into a glass article, and slowly cools it, wherein the apparatus is equipped with a glass observation window that allows the inside of the glass article manufacturing apparatus to be observed from the outside, and the glass observation window has a glass composition within the same range as the glass composition range of the glass article.

Description

Technical Field

[0001] The present disclosure relates to a glass article manufacturing apparatus and a glass article manufacturing method.

Background Art

[0002] There is known a glass article manufacturing apparatus that melts glass raw materials, forms the molten glass obtained by melting into a glass article, and slowly cools it to manufacture a glass article such as sheet glass (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Some glass article manufacturing apparatuses are equipped with a glass observation window for an operator to observe the inside of the apparatus from the outside. When performing maintenance on such a glass article manufacturing apparatus, it is common to break the glass observation window and insert a maintenance tool through the formed opening to perform the work. However, when the glass observation window is broken, glass fragments that constituted the observation window may enter the glass article manufacturing apparatus, and these glass fragments may mix into the glass raw materials or the molten glass. However, in conventional glass article manufacturing apparatuses, no consideration has been given to the composition of the glass of the glass observation window. Therefore, when glass fragments derived from the glass observation window mix into the glass article, the glass composition of the glass article may change, and it may not be possible to obtain a glass article having desired properties.

[0005] One aspect of the present disclosure provides a technique capable of manufacturing a desired glass article even if glass fragments generated by breaking a glass observation window fall inside the glass article forming apparatus.

Means for Solving the Problem

[0006] A glass article manufacturing apparatus according to an aspect of the present disclosure melts a glass raw material to obtain molten glass, forms the molten glass into a glass article, and anneals it. The glass article manufacturing apparatus includes a glass observation window through which the inside of the glass article manufacturing apparatus can be observed from the outside. The glass observation window has a glass composition within the same range as the glass composition range of the glass article.

Advantage of the Invention

[0007] According to an aspect of the present disclosure, even if glass fragments generated by cracking of the glass observation window fall inside the glass article forming apparatus, a desired glass article can be manufactured.

Brief Description of the Drawings

[0008] [Figure 1] It is a schematic diagram of a glass article manufacturing apparatus according to an embodiment of the present disclosure. [Figure 2] It is a schematic enlarged plan view of the glass observation window viewed from the outside. [Figure 3] It is a flowchart of a method for manufacturing a glass article according to an embodiment of the present disclosure.

Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present disclosure will be described in detail. In the description, reference will also be made to the drawings. In the drawings, the same or corresponding components may be denoted by the same reference numerals, and the description thereof may be omitted.

[0010] <Glass Article Manufacturing Apparatus> Figure 1 schematically shows a glass article manufacturing apparatus 100 according to one embodiment of the present disclosure. The glass article manufacturing apparatus 100 is an apparatus that melts glass raw materials, forms the molten glass obtained by melting into a glass article, and slowly cools it. More specifically, the glass article manufacturing apparatus 100 comprises at least a melting apparatus 10, a molding apparatus 30, and a slow cooling apparatus 40. As shown in Figure 1, the glass article manufacturing apparatus 100 may also include a clarifying apparatus 20 for clarifying the molten glass between the melting apparatus 10 and the molding apparatus 30. In Figure 1, the melting apparatus 10, the clarifying apparatus 20, and the molding apparatus 30 are shown as partial breakaway views to facilitate understanding of their functions.

[0011] The melting apparatus 10 melts glass raw materials by heating to produce molten glass Gm. The glass raw materials to be melted may be prepared by mixing multiple types of materials. The glass raw materials may include glass cullet in order to recycle the glass. The glass raw materials may be powdered raw materials or granulated raw materials obtained by granulating the powdered raw materials. In the example shown in Figure 1, the melting apparatus 10 is equipped with a melting tank for containing the molten glass Gm and a burner that emits a flame above the melting tank. However, instead of a burner, an electric heater, electrodes, etc. may be used as the heat source for the melting apparatus 10. The molten glass Gm can be continuously transported from the melting apparatus 10 through the clarification apparatus 20 to the molding apparatus 30. The melting tank of the melting apparatus 10 may be completely covered by a ceiling. In this way, in the melting apparatus 10, the glass raw materials and molten glass Gm inside are surrounded by the melting tank and ceiling, and the heating device as a heat source is further arranged on the outside, so that the inside of the apparatus is not easily visible from the outside.

[0012] The clarification apparatus 20 is a device that removes air bubbles contained in the molten glass Gm obtained in the melting apparatus 10 before it is molded in the molding apparatus 30. Methods for removing air bubbles include, for example, reducing the pressure of the atmosphere surrounding the molten glass or heating the molten glass to a high temperature. The clarification apparatus 20 also includes a clarification tank for containing the molten glass Gm, and the entire upper part of the clarification tank may be covered by a ceiling.

[0013] The molding apparatus 30 molds the molten glass Gm obtained in the melting apparatus 10, and optionally processed in the clarifying apparatus 20, into a glass article Gr of a desired shape. As shown in Figure 1, the glass article Gr may be a long, plate-shaped glass article, i.e., a glass ribbon. The molding apparatus 30 shown in Figure 1 is a molding apparatus using the float method, but the molding method for obtaining the glass article Gr is not limited to the float method and may be the fusion method, roll-out method, etc.

[0014] In the example shown in Figure 1, the molding apparatus 30 is configured as a molding furnace. The molding furnace may consist of a bathtub and a cover connected to and covering the bathtub. Molten metal such as molten tin or molten tin alloy is contained in the bathtub, and molten glass Gm is continuously supplied on top of it. Long, plate-shaped glass articles (glass ribbons) Gr can be formed by utilizing the smooth surface of the molten metal. In the molding apparatus 30, the molten glass Gm and glass articles Gr are surrounded by the melting furnace.

[0015] The annealing device 40 anneales the glass articles Gr formed in the molding device 30. By annealing, glass articles Gr with less residual strain can be obtained. The annealing device 40 may include, for example, a heat treatment furnace and conveying rollers that transport the glass articles in a desired direction inside the heat treatment furnace. The conveying rollers may be arranged in multiples at intervals in the horizontal direction. The glass articles Gr are annealed as they are transported from the inlet to the outlet of the heat treatment furnace. The annealing device 40 may include a chamber that surrounds the glass articles Gr being annealed.

[0016] The annealing device 40 may be backed by a processing device (not shown). The processing device processes the glass article Gr, which has been annealed in the annealing device 40, into a desired shape. The processing device may include one or more selected from, for example, a cutting device, a grinding device, a polishing device, and a coating device. Of these, for example, a cutting device can cut the glass article Gr, which has been annealed in the annealing device 40, to produce a glass plate Gp.

[0017] <Observation window> As described above, each component in the glass article manufacturing apparatus 100 has a wall-like component (also called a wall-like member) that separates the inside from the outside of the apparatus, so that the inside of the apparatus is not easily visible from the outside. For this reason, the glass article manufacturing apparatus 100 is provided with an observation window that allows the inside of the apparatus to be observed from the outside. Through the observation window, the operator can observe the state of the glass raw material, molten glass Gm, and glass article Gr, as well as other internal conditions of the apparatus. The ability to visually observe the inside of the glass article manufacturing apparatus 100 during operation is important for quality control of the glass articles manufactured. The above-mentioned "internal conditions of the apparatus" include the state of the inner surface of the apparatus, the state of the atmosphere inside the apparatus, and, if there are heating devices or the like inside the apparatus, the functional state of such devices.

[0018] The observation window Wd may be provided at any position in the glass article manufacturing apparatus 100. For example, as shown in Figure 1, the observation window Wd may be provided in one or more of the melting apparatus 10, clarifying apparatus 20, molding apparatus 30, and annealing apparatus 40. The observation window Wd may be provided in each of the melting apparatus 10, clarifying apparatus 20, molding apparatus 30, and annealing apparatus 40. In addition, multiple observation windows Wd may be provided in each apparatus.

[0019] Furthermore, in the glass article manufacturing apparatus 100, if one or more of the melting apparatus 10, clarifying apparatus 20, molding apparatus 30, and annealing apparatus 40 are physically separated, the passage between these apparatuses is also included in the glass article manufacturing apparatus 100. In that case, if a chamber is arranged to surround the entire passage, the observation window Wd may be attached to a wall-like member that constitutes such a chamber in the passage.

[0020] The observation window Wd is preferably located on the side of the glass article manufacturing apparatus 100 in the direction of travel of the manufacturing line, as shown in Figure 1, but it may also be located on the ceiling side of the glass article manufacturing apparatus 100.

[0021] The observation window Wd may be formed in a wall-like member that separates the inside from the outside of the glass article manufacturing apparatus 100. For example, if the observation window Wd is attached to the melting apparatus 10, it may be provided on the side wall of the melting tank of the melting apparatus 10, above the surface of the contents inside the tank. If the observation window Wd is provided in the molding apparatus 30, it may be provided on the upper part of the side wall of the melting furnace.

[0022] The observation window Wd may be installed in an opening pre-formed in any wall-like member that separates the inside from the outside of the glass article manufacturing apparatus 100. For example, if the observation window Wd is installed in the melting apparatus 10, the observation window Wd may be installed in an opening formed in the side wall of the melting tank of the melting apparatus 10 at a position above the storage position of the glass raw material and molten glass.

[0023] The observation window Wd is made of glass. This allows for sufficient visibility of the area beyond the observation window Wd and also prevents thermal deformation of the observation window Wd. The observation window Wd may be formed from a glass plate with dimensions of, for example, 50 mm to 250 mm on each side and a thickness of 0.2 mm to 7 mm. Furthermore, in order to suppress heat transfer between the inside and outside of the device through the observation window Wd, that is, to improve the thermal insulation performance of the observation window Wd, the observation window Wd may be made by arranging multiple glass plates with their main surfaces spaced apart. For example, the observation window Wd may be a double-glazed window. An observation window Wd made by arranging multiple glass plates is preferable because it can improve thermal insulation performance.

[0024] Furthermore, the glass observation window Wd is installed tightly to the opening in the wall-like member, that is, in a way that prevents fluid from entering or leaving the space between the observation window Wd and the opening. Preferably, the observation window is installed as a fixed window; that is, the observation window Wd is installed in a way that prevents it from being removed. This ensures sufficient airtightness between the observation window and the wall-like member of the device.

[0025] Figure 2 is a schematic diagram showing an example of the mounting state of the observation window Wd. As an example, Figure 2 is an enlarged view from the outside of a glass observation window Wd attached to the side wall 31 of the molding furnace of the molding apparatus 30 in Figure 1. In the example shown in Figure 2, a metal frame 5 is attached to the opening formed in the side wall 31. Furthermore, the glass observation window Wd may be fixed to this frame 5 using, for example, a heat-resistant and airtight sealant 3. An openable and closable outer cover 6 may be placed on the outside of the glass observation window Wd, for example, pivotally attached to the frame 5. The outer cover 6 is closed when not observing the inside to prevent heat from escaping from inside the apparatus to the outside. Similarly, an openable and closable inner cover 7 may be provided on the inside of the glass observation window Wd. The mounting method of the glass observation window Wd shown in Figure 2 is just one example, and the glass observation window Wd may be mounted in a mounting method known in the art.

[0026] <Relationship between observation windows and glass objects> Glass manufacturing equipment typically requires regular maintenance and inspections. Such maintenance or inspections are performed between the end of one operation and the start of the next. This usually involves breaking an observation window and inserting tools through the resulting opening. Breaking the glass observation window generates glass fragments, some of which inevitably fall into the glass manufacturing equipment. These glass fragments originating from the observation window can contaminate the glass raw materials, molten glass, glass articles being molded, or glass articles being annealed when the equipment is restarted. Although the observation window is also made of glass, its composition has traditionally not been considered. Therefore, if glass fragments from the observation window contaminate the glass articles, the glass composition of the manufactured articles can change, potentially resulting in the loss of desired properties. Furthermore, the glass observation window Wd may unintentionally break during the operation of the glass article manufacturing apparatus 100, even when not undergoing maintenance or inspection, and glass fragments generated at that time may become mixed into the glass articles.

[0027] In contrast, in the glass article manufacturing apparatus 100 according to the embodiment of this disclosure, the glass observation window has a glass composition within the same range as the glass composition range of the glass article. As a result, even if glass fragments generated from the glass observation window break enter the glass article manufacturing apparatus 100 and are further mixed into the glass raw material, molten glass, or the soft glass article after molding, the glass composition of the manufactured glass article will not be affected, or will have little effect. Therefore, even if glass fragments from the glass observation window enter the glass article manufacturing apparatus, a glass article with the desired properties can be manufactured.

[0028] In this specification, "glass composition" or "composition of glass" refers to the types of components that make up the glass in question and the amounts of those components relative to the total amount of glass. Here, the components that make up the glass in "glass composition" may be one or more components that characterize the glass. The components of the glass composition may include oxides of metals or metalloids. Furthermore, specific examples of the types of components in glass composition include SiO2, Al2O3, B2O3, MgO, CaO, SrO, Na2O, K2O, Fe2O3, FeO, ZrO2, Li2O, ZnO, PbO, As2O3, Sb2O3, TiO2, CeO2, SnO2, P2O5, WO3, Bi2O3, Rb2O, Cs2O, CdO, Ga2O3, Y2O3, In2O3, La2O3, Gd2O3, Ce2O3, MnO2, GeO2, TeO2, V2O5, Nb2O5, Ta2O5, As2O5, ThO2, BeO, Lu2O3, Yb2O3, Tb2O3, etc. In addition, the components of glass composition may contain halogen ions (expressed as halogen elements), and specific examples of these include F and Cl.

[0029] Furthermore, the amount of a component in the "glass composition" may include not only the amount of one component mentioned above, but also the total amount of two or more components, as long as they characterize the glass. Note that, if the component is an oxide, the amount of a component relative to the total amount of glass may be expressed in mole percent based on the oxide.

[0030] Therefore, the glass composition may include, for example, amounts of SiO2, Al2O3, B2O3, MgO, CaO, and SrO, or it may include amounts of SiO2, Al2O3, B2O3, MgO, CaO, and SrO, as well as the total amounts of MgO, CaO, and SrO. Alternatively, the glass composition may be amounts of SiO2, Al2O3, B2O3, MgO, CaO, and SrO, as well as the total amounts of MgO, CaO, and SrO. Or, the glass composition may include amounts of SiO2, Al2O3, B2O3, MgO, CaO, SrO, BaO, PbO, As2O3, and Sb2O, as well as the total amounts of MgO, CaO, and SrO.

[0031] Furthermore, in this specification, "range of glass composition" refers to the range of glass composition that is permissible for the glass in question to have the desired properties, and is a numerical range of the amounts of the components constituting the glass. If the glass composition contains two or more components, it refers to the numerical range of each component.

[0032] Therefore, for example, if the glass composition of the glass in question contains an amount of SiO2, the range of the glass composition of the glass in question is, SiO2:a L % or more a U %below It is acceptable to be the case. L The symbol with a subscript L, "a, represents the lower limit of the amount (%) of SiO2, and U The symbol with a subscript U indicates the upper limit of the amount (%) of SiO2. The glass in question may contain any amount of SiO2 within the above range.

[0033] Furthermore, for example, if the glass composition of the glass in question includes the amounts of SiO2, Al2O3, B2O3, MgO, CaO, and SrO, as well as the total amounts of MgO, CaO, and SrO, the range of the glass composition is, SiO2:a L % or more a U %below, Al2O3:b Lb or more% U and below%, B2O3: c L c or more% U and below%, MgO: d L d or more% U and below%, CaO: e L e or more% U and below%, SrO: f L f or more% U and below%, Total of MgO, CaO, and SrO: g L g or more% U and below% may be. In the above, a L、 b L、 The symbol with a subscript L as a U、 )b U、 … is the lower limit value of the amount (%) of each component, and the symbol with a subscript L as the above a

[0034] As described above, in the embodiments of the present disclosure, the glass observation window has a glass composition within the same range as the range of the glass composition of the glass article. In other words, the range of the glass composition of the glass observation window used in the method for manufacturing a glass article can be made the same as the range of the glass composition of the glass article. That is, when the glass composition of the glass article contains each component within a predetermined range, the glass composition of the glass observation window may contain the same each component within the same predetermined range. Therefore, for example, when the glass composition of the glass article contains the amount of SiO2, the amount of Al2O3, the amount of B2O3, the amount of MgO, the amount of CaO, and the amount of SrO, and the total amount of MgO, CaO, and SrO within predetermined ranges, respectively, the glass composition of the glass observation window may also contain the amount of SiO2, the amount of Al2O3, the amount of B2O3, the amount of MgO, the amount of CaO, and the amount of SrO, and the total amount of MgO, CaO, and SrO within the same ranges as the above predetermined ranges, respectively.

[0035] To be more specific, glass articles are expressed in mol% based on oxides. SiO2:a L % or more a U %below, Al2O3:b L % or moreb U %below, B2O3:c L % or morec U %below, MgO:d L % or mored U %below, CaO:e L % or more e U %below, SrO:f L % or more f U %below, Total of MgO, CaO, and SrO: g L % or more g U %below When the glass composition includes, The observation window displays the mol% based on the oxide, SiO2:a L % or more a U %below, Al2O3:b L % or moreb U %below, B2O3:c L % or morec U %below, MgO:d L % or mored U %below, CaO:e L % or more e U %below, SrO:f L % or more f U %below, Total of MgO, CaO, and SrO: g L % or more g U %below It may have a composition that includes [a specific element].

[0036] The type of glass used in the glass articles manufactured according to this embodiment is not particularly limited, but may include, for example, alkali-free glass, soda-lime silicate glass (soda glass), or aluminosilicate glass. "Alkali-free glass" refers to glass that does not substantially contain alkali metal oxides such as Na2O or K2O.

[0037] In this specification, "substantially free" of the target component in the glass composition means that, in mole percent based on oxides, the content of the target component is preferably 1% or less, more preferably 0.5% or less, even more preferably 0.1% or less, and particularly preferably 0.05% or less. Furthermore, it is preferable that the content of the target component is 0%, i.e., that the target component is not present at all.

[0038] In this embodiment, the type of glass used in the glass article and the type of glass used in the glass observation window may be the same. For example, both the glass article and the glass observation window may contain alkali-free glass.

[0039] Furthermore, it is preferable that the glass observation window has substantially the same glass composition as the glass article. This makes it possible to manufacture a glass article that is more faithful to the desired glass composition.

[0040] The following are specific examples of the range of glass compositions for glass articles. (Example 1) In the glass composition of the glass article in Example 1, expressed in mole percent based on oxide, SiO2: 65% to 70% Al2O3: 9% or more and 16% or less, B2O3: 6% or more and 12% or less, MgO: 0% or more and 6% or less, CaO: 0% or more and 7% or less, SrO: 1% or more and 9% or less, Total of MgO, CaO, and SrO: 7% to 18% That's fine.

[0041] Furthermore, it is preferable that the glass article is substantially free of BaO. It is also preferable that the glass article is substantially free of PbO, As2O3, and Sb2O3. Additionally, the phosphorus content of the glass article may be 20 ppm or less in atomic weight.

[0042] As described above, in the glass article manufacturing apparatus 100, the glass observation window has a glass composition within the same range as the glass composition of the glass article. Therefore, for example, if the glass article manufactured by the glass article manufacturing apparatus 100 is the glass article of Example 1, that is, the glass article has a glass composition expressed in mol% based on oxides, SiO2: 65% to 70% Al2O3: 9% or more and 16% or less, B2O3: 6% or more and 12% or less, MgO: 0% or more and 6% or less, CaO: 0% or more and 7% or less, SrO: 1% or more and 9% or less, Total of MgO, CaO, and SrO: 7% to 18% If the glass composition includes, The glass observation window is expressed in mole percent based on oxides. SiO2: 65% to 70% Al2O3: 9% or more and 16% or less, B2O3: 6% or more and 12% or less, MgO: 0% or more and 6% or less, CaO: 0% or more and 7% or less, SrO: 1% or more and 9% or less, Total of MgO, CaO, and SrO: 7% to 18% It has a glass composition that includes [this component].

[0043] (Example 2) In the glass composition of the glass article in Example 2, expressed in mole percent based on oxide, SiO2: 63% to 74% Al2O3: 12% or more and 14% or less, B2O3: more than 1.5% and less than 5%, MgO: 5.5% or more and 13% or less, CaO: 1.5% or more and 12% or less, SrO: 1.5% or more and 9% or less, BaO: 0% or more and 1% or less Total of MgO, CaO, SrO, and BaO: 15.5% to 21% That's fine.

[0044] Furthermore, the above glass articles substantially do not contain BaO, F, Cl, Na2O, K2O, Fe2O3, FeO, and ZrO2. For example, in the above glass composition of the glass articles, Total of Na2O and K2O: 0.1% Fe2O3: 0.1% That's fine.

[0045] Furthermore, the glass articles described above may be substantially free of PbO, As2O3, and Sb2O3, respectively.

[0046] The glass articles in both Example 1 and Example 2 above are all made of alkali-free glass.

[0047] (Example 3) The glass article in Example 3 is aluminosilicate glass. The glass composition range of the glass article is expressed in mole percent based on oxides, SiO2: 50% to 80% Al2O3: 2% or more and 25% or less Li2O: 0% or more and 10% or less Na2O: 0% or more and 18% or less K2O: 0% or more and 10% or less MgO: 0% or more and 15% or less CaO: 0% or more and 5% or less ZrO2: 0% or more and 5% or less Includes.

[0048] <Method for manufacturing glass articles> One embodiment of this disclosure may be a method for manufacturing glass articles using the glass article manufacturing apparatus described above. With this method, even if glass fragments generated from a glass observation window attached to the glass article manufacturing apparatus fall into the apparatus and become mixed with the glass raw materials, molten glass, etc. being processed inside the apparatus, the glass composition of the glass article will not be changed, or will be changed very little. As a result, a glass article with the desired properties can be obtained.

[0049] Figure 3 shows a flowchart of a glass article manufacturing method according to one embodiment of the present disclosure. As shown in Figure 3, this embodiment is a method for manufacturing a glass article using a glass article manufacturing apparatus equipped with a glass observation window that allows the inside of the apparatus to be observed from the outside, and includes: determining a range of desired glass composition of the glass article to be manufactured (S10); preparing a glass observation window having a glass composition within the same range as the determined glass composition range of the glass article (S20); attaching the glass observation window to the glass article manufacturing apparatus to obtain a glass article manufacturing apparatus with an observation window (S30); melting glass raw materials to obtain molten glass in the glass article manufacturing apparatus with an observation window; forming the molten glass into a glass article; and slowly cooling to manufacture the glass article (S40).

[0050] As shown in Figure 3, first in step S10, the desired range of glass composition for the glass article is determined. The range of glass composition for the glass article is, for example, expressed in mole percent based on oxides, SiO2:a L % or more a U %below, Al2O3:b L % or moreb U %below, B2O3:c L % or morec U %below, MgO:d L % or mored U %below, CaO:e L % or more e U %below, SrO:f L% or more f U %below, Total of MgO, CaO, and SrO: g L % or more g U %below It may include [something].

[0051] In step S10, the range of glass composition is determined as described above. Subsequently, in step S20, a glass observation window corresponding to the determined range of glass composition is prepared. More specifically, a glass observation window is prepared that has a glass composition within the same range as the glass composition range of the glass article determined in step S10. To this end, for example, the glass raw material is adjusted so that the glass composition of the glass observation window to be manufactured falls within the range of the glass composition determined in step S10, and a glass plate for the glass observation window is manufactured. The manufacturing of the glass observation window in step S20 may be carried out using the glass article manufacturing apparatus 100 before manufacturing the glass article.

[0052] Here, the preparation of the glass observation window in step S20 may include preparing in advance multiple types of glass observation windows having different glass compositions (S21a), and selecting a glass observation window from the multiple types of glass observation windows that falls within the same range as the glass composition range of the glass article to be manufactured (S22a). That is, as a preparatory step before manufacturing the glass article, multiple glass observation windows, each having a different assumed glass composition, are prepared in step S21a. The preparation of these multiple glass observation windows may, for example, involve manufacturing multiple glass observation windows having different glass compositions using the glass article manufacturing apparatus 100 or another apparatus before manufacturing the glass article, or it may involve processing commercially available glass plates into glass observation windows and storing them in their unprocessed state. Subsequently, in step S22a, a glass observation window having a glass composition within the range of the glass composition of the glass article determined in step S10 is selected from the multiple glass observation windows prepared in step S21a. Then, as shown in Figure 3, the selected glass observation window is installed in step S30.

[0053] Alternatively, instead of steps S21a and S22a described above, the preparation of the glass observation window in step S20 may include manufacturing a glass article prototype using the glass article manufacturing apparatus 100 (S21b), and then manufacturing a glass observation window from the glass article prototype (S22b). In this case, the glass article is a glass plate. In step 21b, before starting the manufacture of the glass article in the glass article manufacturing apparatus 100, a glass article prototype smaller in volume than the glass article to be actually manufactured is manufactured. Then, in step S22b, the glass observation window is manufactured by cutting the glass article prototype made in step S21b to a predetermined size and other processing. In the preparation of the glass observation window including steps S21b and S22b, the glass observation window is manufactured in the same manufacturing apparatus that manufactures the glass article to be actually manufactured. Therefore, the glass composition of the glass observation window can be more reliably kept within the range of the desired glass composition determined in step S10.

[0054] Furthermore, in the glass article manufacturing method according to this embodiment, step S40, in a glass article manufacturing apparatus with an observation window, in which glass raw materials are melted, the molten glass obtained by melting is formed into a glass article, and the glass article is manufactured by slow cooling, is considered as one series of steps in the glass article manufacturing process, and this series of steps is repeated multiple times, and at least some of the fragments generated when the observation window breaks between the series of steps in the glass article manufacturing process may enter the glass article manufacturing apparatus. Therefore, for example, during maintenance between the end of operation of the glass article manufacturing apparatus and restart, even if fragments generated by breaking the observation window to insert an instrument enter the glass article manufacturing apparatus and glass fragments are mixed into the glass raw materials or molten glass, it becomes easy to keep the glass composition of the glass article within the range of the desired glass composition. This makes it possible to manufacture glass articles with desired properties.

[0055] Therefore, one embodiment of the present disclosure is a method for manufacturing a glass article using a glass article manufacturing apparatus equipped with a glass observation window that allows the inside of the apparatus to be observed from the outside, wherein the method involves determining a range of desired glass composition for the glass article to be manufactured (S10), preparing a glass observation window having a glass composition within the same range as the determined glass composition range for the glass article (S20), attaching the glass observation window to the glass article manufacturing apparatus (S30), obtaining a glass article manufacturing apparatus with an observation window, and manufacturing a glass article in the glass article manufacturing apparatus with an observation window by a series of steps including melting a glass raw material, forming the molten glass obtained by the melting into a glass article, and slowly cooling it (S40), repeating the series of steps a number of times, and including that at least a portion of the fragments generated when the observation window breaks between the series of steps enter the glass article manufacturing apparatus.

[0056] Although the present disclosure has been described above based on embodiments, the present disclosure is not limited to these embodiments. Furthermore, the above embodiments can be modified, altered, replaced, added, deleted, and combined in various ways within the scope of the claims, and these also fall within the technical scope of the present disclosure. [Explanation of Symbols]

[0057] 10 Melting equipment 20 Clarification apparatus 30 Molding equipment 40. Slow cooling device 100 Glassware Manufacturing Equipment Wd observation window

Claims

1. A glass article manufacturing apparatus that melts glass raw materials to obtain molten glass, forms the molten glass into a glass article, and slowly cools it, The glass article manufacturing apparatus is equipped with a glass observation window that allows the inside to be observed from the outside, A glass article manufacturing apparatus wherein the glass observation window has a glass composition within the same range as the glass composition range of the glass article.

2. The glass composition of the aforementioned glass article is SiO ２ Quantity, Al ２ O ３ Amount, B ２ O ３ The amounts of MgO, CaO, and SrO, as well as the total amounts of MgO, CaO, and SrO, are each within a predetermined range. The glass composition of the glass observation window also contains the amount of SiO ２ , the amount of Al ２ O ３ , the amount of B ２ O ３ , the amount of MgO, the amount of CaO, the amount of SrO, and the total amount of MgO, CaO, and SrO within the same ranges as the respective predetermined ranges, the glass article manufacturing apparatus according to claim 1.

3. The glass article manufacturing apparatus according to claim 2, wherein both the glass article and the glass observation window include alkali-free glass.

4. The glass articles are expressed in mol% based on oxides, SiO ２ 65% to 70% Al ２ O ３ : 9% to 16% B ２ O ３ 6% to 12% MgO: 0% or more and 6% or less, CaO: 0% or more and 7% or less, SrO: 1% or more and 9% or less, Total of MgO, CaO, and SrO: 7% to 18% A glass article manufacturing apparatus according to claim 2, having a glass composition including the following:

5. The glass articles are expressed in mol% based on oxides, SiO ２ 63% to 74% Al ２ O ３ 12% to 14% B ２ O ３ 1.5% above 5% MgO: 5.5% or more and 13% or less, CaO: 1.5% or more and 12% or less, SrO: 1.5% or more and 9% or less, BaO: 0% or more and 1% or less Total of MgO, CaO, SrO, and BaO: 15.5% to 21% A glass article manufacturing apparatus according to claim 2, having a glass composition including the following:

6. The glass article manufacturing apparatus according to claim 4 or 5, wherein neither the glass article nor the glass observation window substantially contains BaO.

7. Both the aforementioned glass article and the aforementioned glass observation window are made of PbO and As ２ O ３ , and Sb ２ O ３ A glass article manufacturing apparatus according to claim 4 or 5, which substantially does not contain the specified substance.

8. The glass article manufacturing apparatus according to claim 1 or 2, wherein the glass observation window has substantially the same glass composition as the glass article.

9. The glass article manufacturing apparatus according to claim 1 or 2, wherein the glass observation window is a fixed window tightly fitted into an opening in a wall-like member of the glass article manufacturing apparatus.

10. A method for manufacturing glass articles using a glass article manufacturing apparatus equipped with a glass observation window that allows the inside of the apparatus to be observed from the outside, Determine the desired range of glass composition for the glass articles to be manufactured. A glass observation window is prepared having a glass composition within the same range as the glass composition range determined for the glass article. The glass observation window is attached to the glass article manufacturing apparatus to obtain a glass article manufacturing apparatus with an observation window. A method for manufacturing glass articles, comprising: melting glass raw materials to obtain molten glass in the glass article manufacturing apparatus with an observation window; forming the molten glass into a glass article; and slowly cooling the glass article.

11. The preparation of the aforementioned glass observation window is Multiple types of glass observation windows with different glass compositions are prepared in advance. The method for manufacturing a glass article according to claim 10, further comprising selecting from the plurality of glass observation windows a glass observation window having a glass composition within the same range as the glass composition range of the glass article to be manufactured.

12. The preparation of the aforementioned glass observation window is Using the aforementioned glass article manufacturing apparatus, a prototype glass article is produced. A method for manufacturing a glass article according to claim 10, further comprising manufacturing a glass observation window from the glass article prototype.

13. A method for manufacturing glass articles using a glass article manufacturing apparatus equipped with a glass observation window that allows the inside of the apparatus to be observed from the outside, Determine the desired range of glass composition for the glass articles to be manufactured. A glass observation window is prepared having a glass composition within the same range as the glass composition range determined for the glass article. The glass observation window is attached to the glass article manufacturing apparatus to obtain a glass article manufacturing apparatus with an observation window. In the aforementioned glass article manufacturing apparatus with an observation window, a glass article is manufactured by a series of steps including melting glass raw materials, forming the molten glass obtained by the melting into a glass article, and slowly cooling it. Repeat the above series of steps multiple times. A method for manufacturing a glass article, comprising the following: between the above-mentioned series of steps and the next series of steps, at least a portion of the fragments generated when the observation window breaks enters the glass article manufacturing apparatus.

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