Glass forming apparatus and method for manufacturing glass article

Abstract

The invention provides a glass forming device and a manufacturing method of a glass article. The glass forming device can alleviate stress concentration at corners of a pressure-receiving surface portion of a formed body, wherein the stress concentration may be generated when a horizontal load acts on the pressure-receiving surface portion from a support brick, thereby inhibiting damage of the formed body. A glass molding device (1) is provided with: a molding body (2); a support brick (3) that supports the molded body (2); a pressure-receiving surface section (2b) that is present in the molded body (2) and has corner sections (2bx, 2by); the glass forming apparatus (1) includes a support brick (3), a pressure-receiving surface (2b) disposed on the support brick (3), and a pressing surface (3c) disposed on the support brick (3) and facing the pressure-receiving surface (2b), the glass forming apparatus (1) is configured so that a horizontal load acts on the pressure-receiving surface (2b) of the forming body (2) from the support brick (3), a buffer plate (4) is interposed between the pressure-receiving surface (2b) and the pressing surface (3c), and the buffer plate (4) is disposed so as to form gaps (T1, T2) between corners (2bx, 2by) of the pressure-receiving surface (2b) and the pressing surface (3c).

Description

Technical Field

[0001] The present invention relates to a glass forming device configured to support a formed body by using support bricks, and a method for manufacturing a glass article using the glass forming device. Background Art

[0002] For example, a molded body used in the overflow down-draw method generally supports only both ends in the longitudinal direction from below, so creep deformation occurs over time, such that the central portion in the longitudinal direction sags due to high operating temperature and the weight of the molded body.

[0003] Such deformation of the forming body has a negative impact on the quality and size of the glass ribbon formed by the forming body and the product glass, so a means of reducing the deformation is needed. As such a means, it is proposed to apply a horizontal load from both ends of the forming body in the longitudinal direction toward the center of the longitudinal direction to reduce the deadweight load of the forming body.

[0004] As a specific example, Patent Documents 1 and 2 disclose that a horizontal load is applied to pressure receiving surfaces at both ends of the formed body in the longitudinal direction from supporting bricks that support both ends of the formed body from below.

[0005] In this case, the lower part of the formed body is wedge-shaped or substantially wedge-shaped, and the support brick is arranged at the lower part of the formed body, so the pressure-receiving surface of the formed body has a corner. In addition, the support brick has a pressing surface facing the pressure-receiving surface of the formed body.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2004-284843

[0009] Patent Document 2: International Publication No. 2018 / 232092 Summary of the invention

[0010] Problems to be solved by the invention

[0011] The means disclosed in Patent Documents 1 and 2 are that the pressure surface of the formed body is in direct contact with the pressing surface of the supporting brick. According to the research results obtained by the present inventors, in this state, when the required horizontal load acts on the pressure surface of the formed body from the supporting brick, stress concentration occurs at the corner of the pressure surface. And this may cause the formed body to break.

[0012] From the above viewpoints, an object of the present invention is to alleviate stress concentration at the corners of the pressure-receiving surface that may be generated when a horizontal load acts on the pressure-receiving surface of a formed body from a supporting brick, thereby suppressing breakage of the formed body.

[0013] Solutions to Solve Problems

[0014] (1) The first aspect of the present invention made to solve the above-mentioned problems is a glass forming device, comprising: a forming body; a supporting brick that supports the forming body; a pressure surface that exists on the forming body and has a corner; and a pressing surface that exists on the supporting brick and is opposite to the pressure surface, wherein the glass forming device is configured to apply a horizontal load from the supporting brick to the pressure surface, and the glass forming device is characterized in that a buffer plate is sandwiched between the pressure surface and the pressing surface, and the buffer plate is arranged in a manner to form a gap between the corner of the pressure surface and the pressing surface. It should be noted that the glass forming device is suitable for use in the case of forming a glass ribbon using a down-draw method, particularly an overflow down-draw method.

[0015] According to the structure of (1) above, by interposing the buffer plate between the pressure-receiving surface of the formed body and the pressing surface of the supporting brick, a gap is formed between the corner of the pressure-receiving surface and the pressing surface. Therefore, even if a horizontal load acts on the pressure-receiving surface of the formed body from the supporting brick, stress concentration that may occur at the corner of the pressure-receiving surface is alleviated, thereby suppressing damage to the formed body.

[0016] (2) In the structure of (1) above, the pressure receiving surface may be in a wedge shape or a substantially wedge shape having one corner at the lower end and two corners at the upper end, and the buffer plate may be arranged in a manner to form a gap between the corner at the lower end of the pressure receiving surface and the pressing surface.

[0017] In this way, stress concentration is alleviated at the corner portion of the lower end portion where stress concentration is most likely to occur in the pressure receiving surface portion having a wedge shape or a substantially wedge shape.

[0018] (3) In the configuration of (2) above, the buffer plate may be arranged so as to form gaps between the pressing surface portion and two corners of the upper end portion of the pressure receiving surface portion.

[0019] Thus, stress concentration is relieved not only at the corner of the lower end of the pressure receiving surface but also at the two corners of the upper end. Therefore, stress concentration is relieved in the entire region of the pressure receiving surface that is in a wedge shape or a substantially wedge shape.

[0020] (4) In the configuration of (3) above, the buffer plate may have a wedge shape having one corner at the lower end and two corners at the upper end, in which three corners are missing.

[0021] In this manner, the buffer plate only needs to have the three corners of the wedge shape cut out, so that the buffer plate for forming gaps between the three corners of the pressure receiving surface portion and the pressing surface portion can be easily manufactured.

[0022] (5) In any one of the above structures (1) to (4), the outer contour of the buffer plate may be located inside the outer contour of the pressure receiving surface portion over the entire circumference.

[0023] Thus, a gap is formed between the pressure-receiving surface and the pressing surface not only at the corners of the pressure-receiving surface but also at the entire circumference. Therefore, stress concentration is alleviated not only at the corners of the pressure-receiving surface but also at the entire circumference, further suppressing the breakage of the formed body.

[0024] (6) In any of the above (1) to (5), under the condition of stress F / A obtained by dividing the load F pressing the support brick to apply a horizontal load to the pressure surface by the area A of the pressure surface, the creep strain rate of the support brick is set to R and the creep strain rate of the buffer plate is set to P, so that the relationship (R / P) < 1 is satisfied.

[0025] Thus, the creep strain rate of the buffer plate is greater than that of the supporting brick, so even if a large stress is generated in the buffer plate between the pressure receiving surface and the pressing surface, the stress can be quickly relieved. As a result, creep fracture of the buffer plate due to the large stress can be avoided.

[0026] (7) In any one of the above structures (1) to (6), the buffer plate may be formed of a platinum group element as a main component.

[0027] In this way, creep rupture of the buffer plate caused by large stress generated in the buffer plate can be appropriately suppressed.

[0028] (8) In any one of the above structures (1) to (7), the pressing surface portion may have an inclined portion that gradually moves away from the pressure receiving surface portion as it goes toward the outer peripheral side, and the inclined portion may face a corner portion of the pressure receiving surface portion.

[0029] Thus, even if the creep deformation of the supporting brick progresses in the direction of the horizontal load and the corners of the pressing surface and the pressed surface come into contact, the presence of the inclined portion of the pressing surface prevents the contact between the two. Thus, the device can be used for a long time and its durability is improved.

[0030] (9) In any one of the above-mentioned structures (1) to (7), the pressing surface portion may have a recessed portion, and the recessed portion may face a corner portion of the pressure receiving surface portion.

[0031] In this case, even if the corners of the pressing surface and the pressure receiving surface can contact each other due to creep deformation of the supporting brick in the direction of the horizontal load, the contact between the two can be avoided by the presence of the concave portion of the pressing surface. In this case, the device can be used for a long time and its durability is improved.

[0032] (10) In any one of the above-mentioned structures (1) to (9), a plurality of buffer plates may be interposed between the pressure receiving surface portion and the pressing surface portion.

[0033] In this way, the gap between the corner of the pressure surface and the pressing surface can be kept wide, so even if the creep deformation of the supporting brick progresses in the direction of the horizontal load, a gap can be maintained between the two. Thus, contact between the two is avoided. In this case, the device can be used for a long time and its durability is improved.

[0034] (11) In any one of the above structures (1) to (10), a buffer auxiliary plate extending outward from both side edges and a lower end edge of the pressing surface portion may be interposed between the pressing surface portion and the buffer plate.

[0035] Thus, even if the corner of the pressure receiving surface portion and the pressing surface portion come into contact due to creep deformation of the supporting brick in the direction in which the horizontal load acts, the presence of the buffer auxiliary plate prevents direct contact between the two.

[0036] (12) In the structure of (11) above, under the condition of stress F / A obtained by dividing the load F pressing the supporting brick to apply a horizontal load to the pressure surface by the area A of the pressure surface, the creep strain rate of the supporting brick is set to R and the creep strain rate of the buffer auxiliary plate is set to Pa, so that the relationship (R / Pa)>1 is satisfied.

[0037] Thus, even if the creep deformation of the supporting brick progresses in the direction of the horizontal load and the corner of the pressure receiving surface portion comes into contact with the buffer auxiliary plate, the contact between the two is avoided because the relationship (R / Pa)>1 is satisfied.

[0038] (13) In any one of the above (1) to (12), the refractory used in the supporting brick may have a compressive creep deformation of 0.3% or less when subjected to a pressure of 0.5 MPa in an atmosphere at 1400°C for 100 hours.

[0039] In this way, the support bricks are formed using a refractory material that is difficult to creep deform. Therefore, the horizontal load acting from the support bricks on the pressure-receiving surface of the formed body can be increased, and the creep deformation of the formed body can be further suppressed.

[0040] (14) In any one of the above (1) to (13), the refractory used in the supporting brick may be arranged in a 1300°C atmosphere with the longitudinal direction of the refractory sheet having a longitudinal dimension of 20 mm, a lateral dimension of 25 mm and a length direction of 75 mm, and supported at both ends in the longitudinal direction in a horizontal direction. When a load of 2 kg is applied vertically downward to the center portion in the longitudinal direction for 100 hours, the maximum deflection of the refractory sheet in the vertical direction is less than 0.5 mm.

[0041] In this way, the support bricks are formed using a refractory material that is difficult to creep deform. Therefore, the horizontal load acting from the support bricks on the pressure-receiving surface of the formed body can be increased, and the creep deformation of the formed body can be further suppressed.

[0042] (15) A second aspect of the present invention made to solve the above-mentioned problems is a method for manufacturing a glass article, characterized in that the method includes a forming step of forming a glass ribbon from molten glass using any one of the glass forming apparatuses described in (1) to (14).

[0043] According to this method, substantially the same operational effects as those described with respect to any one of the glass forming apparatuses (1) to (14) above can be obtained.

[0044] Effects of the Invention

[0045] According to the present invention, stress concentration at the corners of the pressure receiving surface portion that may be generated when a horizontal load acts on the pressure receiving surface portion of the formed body from the supporting bricks is alleviated, thereby suppressing breakage of the formed body. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a front view showing the overall structure of a glass forming apparatus according to a first example of the first embodiment of the present invention.

[0047] Figure 2 It shows that according to Figure 1 The cross section is cut along the JJ line of FIG. 8 and is a perspective view showing a state in which a buffer plate is arranged on the pressure receiving surface portion.

[0048] Figure 3 This is a perspective view showing a supporting brick of a glass forming apparatus according to a first example of the first embodiment of the present invention.

[0049] Figure 4 It is a side view showing a pressure receiving surface portion and a buffer plate of a glass forming apparatus according to a first example of the first embodiment of the present invention.

[0050] Figure 5 is in accordance with Figure 4The enlarged longitudinal section main view obtained by cutting along the K-K line.

[0051] Figure 6 is in accordance with Figure 4 An enlarged longitudinal section view obtained by cutting along the L-L line.

[0052] Figure 7 This is a perspective view for explaining the characteristics of the supporting brick of the glass forming apparatus according to the first example of the first embodiment of the present invention.

[0053] Figure 8 This is a perspective view for explaining the characteristics of the supporting brick of the glass forming apparatus according to the first example of the first embodiment of the present invention.

[0054] Fig. 9 This is a perspective view showing a supporting brick of a glass forming apparatus according to a first example of the first embodiment of the present invention.

[0055] Fig.10 It is a front view showing the main part structure of the glass forming apparatus of the first example of the first embodiment of the present invention.

[0056] Fig.11 It is a front view showing the main part structure of the glass forming apparatus of the second example of the first embodiment of the present invention.

[0057] Fig.12 This is a perspective view showing a supporting brick of a glass forming apparatus according to a second example of the first embodiment of the present invention.

[0058] Fig.13 It is a side view showing a pressure receiving surface portion and a buffer plate of a glass forming apparatus according to a second example of the first embodiment of the present invention.

[0059] Fig.14 is in accordance with Fig.13 An enlarged longitudinal section view obtained by cutting along the M-M line.

[0060] Fig.15 This is a side view showing the stress distribution which is the result of numerical analysis on the pressure receiving surface portion of the glass forming apparatus according to the second example of the first embodiment of the present invention.

[0061] Fig.16 It is a side view showing a pressure receiving surface portion and a buffer plate of a glass forming apparatus according to a third example of the first embodiment of the present invention.

[0062] Fig.17 It is a front view showing the main part structure of the glass forming apparatus according to the fourth example of the first embodiment of the present invention.

[0063] Fig.18It is a side view showing a pressure receiving surface portion and a buffer plate of a glass forming apparatus according to a fourth example of the first embodiment of the present invention.

[0064] Fig.19 It is a perspective view showing a supporting brick and a buffer plate of a glass forming apparatus according to a first example of a second embodiment of the present invention.

[0065] Fig. 20 This is an enlarged longitudinal sectional front view showing the main part of the glass forming apparatus according to the first example of the second embodiment of the present invention cut at the center in the width direction.

[0066] Fig.21 It is a perspective view showing a supporting brick and a buffer plate of a glass forming apparatus according to a second example of the second embodiment of the present invention.

[0067] Fig. 22 It is a perspective view showing a supporting brick and a buffer plate of a glass forming apparatus according to a third example of the second embodiment of the present invention.

[0068] Fig.23 It is a perspective view showing a supporting brick, a buffer plate, and a buffer auxiliary plate of a glass forming apparatus according to a fourth example of the second embodiment of the present invention.

[0069] Fig.24 This is an enlarged longitudinal sectional front view showing a main part of a glass forming apparatus according to a fourth example of the second embodiment of the present invention cut at the center in the width direction.

[0070] Fig.25 This is an enlarged longitudinal sectional front view showing a main part of a glass forming apparatus according to a fourth example of the second embodiment of the present invention cut at the center in the width direction.

[0071] Fig.26 This is a side view showing the problems of the conventional glass forming apparatus and the result of numerical analysis on the pressure receiving surface portion, that is, stress distribution.

[0072] Fig. 27 This is an enlarged longitudinal sectional front view showing the main part of the glass forming device cut at the center in the width direction, illustrating the problems of the conventional glass forming device.

[0073] Fig.28 This is a side view showing the problems of the conventional glass forming apparatus and the result of numerical analysis on the pressure receiving surface portion, that is, stress distribution.

[0074] Description of Reference Numerals

[0075] 1 Glass forming device

[0076] 2 formed body

[0077] 2b Pressure face

[0078] 2bx Corner at the lower end of the pressure surface

[0079] 2by The corner of the upper end of the pressure surface

[0080] 3 Support bricks

[0081] 3c Press the face

[0082] 3e Inclined part

[0083] 3f concavity

[0084] 4 Buffer plate

[0085] 4a Missing part

[0086] 7 Buffer auxiliary plate

[0087] T1 gap

[0088] T2 gap

[0089] T3 gap

[0090] T4 gap. DETAILED DESCRIPTION

[0091] Hereinafter, a glass forming apparatus and a method for producing a glass article according to an embodiment of the present invention will be described with reference to the drawings. It should be noted that the glass forming apparatus according to the following embodiment is used when forming a glass ribbon by an overflow down-draw method.

[0092] <First embodiment>

[0093] Figure 1 1 is a front view showing the overall structure of a glass forming device 1 of a first example of a first embodiment of the present invention. It should be noted that in the following description, the A-A direction shown in the figure is recorded as the longitudinal direction. As shown in the figure, the glass forming device 1 has support bricks 3 that support the two ends of the longitudinal direction of the forming body 2 from below. The upper surfaces 3a of the two support bricks 3 are in contact with the support surfaces 2a respectively provided at the two ends of the width direction of the forming body 2. The weight of the forming body 2 is borne only by the two support bricks 3.

[0094] There are pressure-bearing surfaces 2b at both ends of the formed body 2 in the width direction. It is a structure in which horizontal loads are applied to the two pressure-bearing surfaces 2b from the two supporting bricks 3. And, in order to make these horizontal loads act on the two pressure-bearing surfaces 2b, it is a structure in which the two supporting bricks 3 are pressed in the direction of the arrow X by the action of a pressure device (not shown in the figure). In the first example of this embodiment, the pressure device presses only one supporting brick 3 in the direction of the arrow X, and the other supporting brick 3 is restricted from retreating along the length direction by a stopper member (not shown in the figure) which is a stopper fixed at a fixed position. Therefore, the stopper member also presses the other supporting brick 3 in the direction of the arrow X. It should be noted that the pressure device can also press both supporting bricks 3 in the direction of the arrow X. The pressure device is composed of a fluid pressure cylinder such as an air cylinder and a hydraulic cylinder, a device using a servo motor, and the like. In addition, the stopper member is composed of a member forming a furnace wall surrounding the formed body 2, a member separately installed on the furnace wall, and the like.

[0095] Buffer plates 4 are respectively interposed between the two pressure-bearing surfaces 2b of the forming body 2 and the two supporting bricks 3. Here, the glass forming device 1 has the same structure at one end and the other end in the longitudinal direction, so only one end in the width direction of the glass forming device 1 (the left end in the width direction in the example) is described below.

[0096] Figure 2 It shows that according to Figure 1 A cross section obtained by cutting along the J-J line of the figure and showing a three-dimensional view of a state in which a buffer plate 4 is arranged on the pressure-receiving surface 2b. It should be noted that in the following description, the BB direction shown in the figure is recorded as the width direction. As shown in the figure, an overflow groove 2x is formed in the upper part of the formed body 2. The lower part of the formed body 2 is wedge-shaped, and the entire area below the support surface 2a is wedge-shaped. Therefore, the pressure-receiving surface 2b is a wedge-shaped having one corner 2bx at the lower end and two corners 2by at the upper end.

[0097] Figure 3 : is a three-dimensional view showing the supporting brick 3. In this figure, dot-dash lines are used to depict the projection of the pressure-bearing surface 2b and the buffer plate 4 on the entire surface area of ​​the pressing side of the supporting brick 3 along the length direction, that is, the pressing surface 3b as the entire surface area of ​​the side pressing the pressure-bearing surface 2b. The surface area on which the pressure-bearing surface 2b is projected in the pressing surface 3b of the supporting brick 3 is the pressing surface 3c. That is, the pressure-bearing surface 2b and the pressing surface 3c are opposite to each other, so the outer contour line of the pressure-bearing surface 2b and the outer contour line of the pressing surface 3c are consistent throughout the circumference when viewed along the length direction. Therefore, as can be seen from Figure 2 as well as Figure 3 As can be understood, the buffer plate 4 is interposed between the pressure receiving surface portion 2 b of the formed body 2 and the pressing surface portion 3 c of the supporting brick 3 .

[0098] The pressure-bearing surface 2b of the present embodiment is a single plane portion. Therefore, in the first example of the present embodiment, the entire surface area below the supporting surface 2a in the formed body 2 is the pressure-bearing surface 2b. Therefore, in this first example, the height position of the upper end of the pressure-bearing surface 2b is the same as the height position of the supporting surface 2a of the formed body 2. In addition, the height position of the upper end of the pressing surface 3c is the same as the height position of the upper end of the pressing surface 3b of the supporting brick 3. On the other hand, the height position of the lower end of the pressure-bearing surface 2b (the height position of the lower end of the pressing surface 3c is also the same) is slightly higher than the height position of the lower end of the pressing surface 3b of the supporting brick 3.

[0099] like Figure 4 As shown in the figure, the corner 2bx at the lower end of the pressure-receiving surface 2b is an area surrounded by a circle S1 represented by a dashed line with the vertex 2ba at the lower end of the wedge shape as the center. In addition, the two corners 2by at the upper end of the pressure-receiving surface 2b are areas surrounded by circles S2 represented by a dashed line with the two vertices 2bb at the upper end of the wedge shape as the center.

[0100] The buffer plate 4 is in a wedge shape having one corner at the lower end and two corners at the upper end, and the three corners are missing. In the example, the three missing parts 4a are in an arc shape, but they can also be in other shapes such as a straight line or a polygonal shape. The outer line of the buffer plate 4 is located inside the outer line of the pressure surface 2b over the entire circumference. In addition, the buffer plate 4 is arranged to avoid the three corners 2bx and 2by of the pressure surface 2b. The thickness of the buffer plate 4 is 1.0 to 5.0 mm. The lower limit of the thickness is preferably 1.5 mm. In addition, the upper limit of the thickness is preferably 3.0 mm.

[0101] Figure 5 is in accordance with Figure 4 As shown in the figure, a buffer plate 4 is sandwiched between the pressure-bearing surface 2b of the formed body 2 and the pressing surface 3c of the supporting brick 3, so that a gap T1 is formed between the corner 2bx at the lower end of the pressure-bearing surface 2b and the pressing surface 3c. Figure 6 is in accordance with Figure 4 As shown in the figure, by sandwiching the buffer plate 4 in the same manner as described above, a gap T2 is formed between the corner 2by on one side of the upper end of the pressure-receiving surface 2b and the pressing surface 3c. A gap is also formed in the same manner at the corner 2by on the other side of the upper end of the pressure-receiving surface 2b.

[0102] By forming the gaps T1 and T2 in this way, the stress concentration generated at the three corners 2bx and 2by of the pressure receiving surface portion 2b in the absence of the buffer plate 4 is alleviated. Figure 4As shown, the corner 2bx at the lower end of the pressure-receiving surface 2b has a small angle, so stress concentration occurs in a relatively wide area. Therefore, the separation length L1 from the vertex 2ba of the corner 2bx to the buffer plate 4 is relatively long. In contrast, the two corners 2by at the upper end of the pressure-receiving surface 2b have a larger angle than the angle of the corner 2bx at the lower end, so stress concentration occurs in a relatively narrow area. Therefore, the separation length L2 from the vertex 2bb of these corners 2by to the buffer plate 4 is relatively short. By configuring the buffer plate 4 in this way, the stress concentration generated at the corner 2bx at the lower end of the pressure-receiving surface 2b and the stress concentration generated at the two corners 2by at the upper end of the pressure-receiving surface 2b are effectively alleviated.

[0103] Hereinafter, characteristics and the like of the supporting brick 3, the buffer plate 4, and the formed body 2 used in the first example of the present embodiment will be described.

[0104] When a load F (towards the support brick 3) is applied to the pressure receiving surface 2b so as to apply a horizontal load from the support brick 3 to the pressure receiving surface 2b, Figure 1 Under the condition of stress F / A obtained by dividing the load F pressing the support brick 3 in the direction of the arrow X shown by the area A of the pressure surface 2b, when the creep strain rate of the support brick 3 is set to R and the creep strain rate of the buffer plate is set to P, the relationship (R / P) < 1 is satisfied. In this case, the load F of the pressure device pressing the support brick 3 on one side is the same as the load F of the bearing member pressing the support brick 3 on the other side. The buffer plate 4 is formed of platinum in this embodiment, but it can also be formed of platinum alloy, reinforced platinum, reinforced platinum alloy, etc., and can also be formed of other platinum group elements, such as palladium, rhodium, etc. In addition, the buffer plate 4 can be formed of a material with a creep strain rate greater than that of the support brick 3, and can also be a material other than the above-mentioned materials.

[0105] Thus, even when a large stress is generated in the buffer plate 4 between the pressure surface 2b and the pressing surface 3c, the stress can be quickly relieved because the creep strain rate of the buffer plate 4 is greater than the creep strain rate of the supporting brick 3. As a result, the stress generated in the buffer plate 4 can be reduced, and the buffer plate 4 can be prevented from creeping and rupturing due to the large stress.

[0106] The buffer plate 4 is subjected to surface treatment by sputtering, thermal spraying, etc. In this case, it is preferable to perform zirconium oxide thermal spraying on the buffer plate 4 to prevent slipping. The molded body 2 is formed of a material having a creep strain rate R smaller than that of the support brick 3 .

[0107] The amount of compressive creep deformation of the refractory used in the supporting brick 3 when a pressure of 0.5 MPa is applied in an atmosphere of 1400° C. for 100 hours is 0.3% or less (preferably 0.15% or less). Accordingly, in order to obtain a supporting brick 3 that is less likely to undergo creep deformation, the horizontal load acting from the supporting brick 3 on the pressure-receiving surface 2b of the formed body 2 can be increased to, for example, 0.1 MPa or more, preferably 0.2 MPa or more, more preferably 0.3 MPa or more, and even more preferably 0.4 MPa or more, and the creep deformation of the formed body 2 can be further suppressed.

[0108] In addition, the refractory used in the supporting brick 3 also has the following characteristics. Figure 7 As shown in FIG. 1 , a refractory sheet 3p having a longitudinal dimension Lx of 20 mm, a transverse dimension Ly of 25 mm, and a lengthwise dimension Lz of 75 mm is prepared. Then, the refractory sheet 3p is heated in an atmosphere at 1300° C. as follows. Figure 8 As shown, the two ends of the longitudinal direction are arranged and supported in a manner that the longitudinal direction is along the horizontal direction. In this state, a counterweight W is placed in the central part of the longitudinal direction of the refractory sheet 3p (the area where the dimension Lw in the longitudinal direction in the central part is 20mm), and a load of 2kg is applied vertically downward under the action of the counterweight W. Further, in this state, the maximum deflection amount of the refractory sheet 3p in the vertical direction after 100 hours is measured. The result of the measurement is less than 0.5mm. Therefore, in order to obtain a supporting brick 3 that is difficult to creep deform, the horizontal load acting from the supporting brick 3 to the pressure surface 2b of the formed body 2 can be increased to, for example, 0.1MPa or more, preferably 0.2MPa or more, more preferably 0.3MPa or more, and even more preferably 0.4MPa or more, which can further suppress the creep deformation of the formed body 2.

[0109] Fig. 9 as well as Fig.10 Preferred means for reliably preventing the buffer plate 4 from being displaced or falling are respectively exemplified. Fig. 9 The means exemplified in the example is to form a depression 5 of the same shape as the buffer plate 4 on the pressing surface 3b of the supporting brick 3 and to insert the buffer plate 4 into the depression 5. In this case, it is preferable to increase the thickness of the buffer plate 4 described above by an amount corresponding to the depth of the depression 5. The depth of the depression 5 is preferably about 0.2 to 3 mm. Fig.10The means illustrated in the example is to form a buffer plate 4 integrally with a restriction portion 6 which is sometimes used as a component of the forming body 2. The restriction portion 6 is provided at both ends of the forming body 2 in the longitudinal direction and restricts the outflow of the molten glass to the outside in the longitudinal direction. Furthermore, the restriction portion 6 is formed of a plate such as platinum, and covers the surface portion of the lower part of the forming body 2 which is opposite to the pressing surface portion 3c. Therefore, there is a pressure surface portion 2b at the portion of the restriction portion 6 which covers the surface portion. It should be noted that the glass forming device 1 described above does not adopt such means, and the glass forming device 1 described later also does not adopt such means. The restriction portion 6 may be adopted in the glass forming device 1 described above, and a structure in which the buffer plate 4 is integrally formed in the restriction portion 6 may be adopted.

[0110] Fig.11 1 is a front view showing the main part structure of the glass forming device 1 according to the second example of the first embodiment of the present invention. Fig.12 is a perspective view showing the supporting brick 3 of the device 1, Fig.13 : is a side view showing the pressure-bearing surface 2b and the buffer plate 4 of the device 1. As shown in the above figures, the glass forming device 1 of the second example is different from the glass forming device 1 of the above-mentioned first example in that a planar chamfered surface 3d is formed at the upper end of the pressing surface 3b of the supporting brick 3 and a curved chamfered surface 2d is formed above the pressure-bearing surface 2b. In the second example, the height positions of the upper and lower ends of the chamfered surface 3d of the pressing surface 3b are the same as the height positions of the upper and lower ends of the chamfered surface 2d above the pressure-bearing surface 2b. In this case, the pressure-bearing surface 2b is a single planar portion as described above, so as Fig.11 as well as Fig.13 As shown in FIG. 1 , the height position of the upper end of the pressure-receiving surface 2b is the same as the height position of the lower end of the chamfered surface 2d. Fig.13 As shown in FIG. 1 , the height position of the upper end of the pressure-receiving surface 2b is lower than the height position of the upper end of the pressure-receiving surface 2b shown in the first example (a straight line Lb extending in the width direction indicated by a dashed line in the figure) by the height of the chamfered surface 2d. Fig.12 As shown, the height position is the same as the lower end of the chamfered surface 3d.

[0111] Here, if Fig.13 As shown, two corners 2by of the upper end of the pressure receiving surface portion 2b are regions surrounded by circles S2 indicated by dashed lines with two vertices 2bb located at lower positions than in the first example as centers. Fig.14 is in accordance with Fig.13An enlarged sectional view obtained by cutting along the M-M line. As shown in the figure, by sandwiching a buffer plate 4 between the pressure-bearing surface 2b of the formed body 2 and the pressing surface 3c of the supporting brick 3, a gap T2 is formed between the corner 2by on one side of the upper end of the pressure-bearing surface 2b and the pressing surface 3c. A gap T2 is also formed in the same manner with respect to the corner 2by on the other side of the pressure-bearing surface 2b. In addition, a gap T1 is formed with respect to the corner 2bx at the lower end of the pressure-bearing surface 2b, as in the case of the first example. This second example is the same as the first example described above except for the structure described here, and therefore the components common to both are described in detail below. Figure 11 to Figure 14 The same reference numerals are used to denote the same reference numerals and their descriptions are omitted.

[0112] The present inventors have performed the following numerical analysis on the second example, and the gist and analysis results will be described below.

[0113] Suitable materials for each component constituting the glass forming apparatus 1 can be determined by performing a numerical analysis assuming the horizontal loads and temperatures described above that are expected to be experienced during operation of the apparatus 1. In this numerical analysis, the creep phenomenon of the support brick 3 is reproduced using the creep strain rate (dδ / dt) of each component, which is expressed by an exponential law expression such as the following formula 1.

[0114] dδ / dt=Aσnexp(-Q / T) Equation 1

[0115] Here, δ is strain, t is time, T is temperature, σ is stress obtained by dividing the horizontal load by the area of ​​the pressure-bearing surface portion 2b, and A, n, and Q are constants determined by the material.

[0116] Fig.26 The results of numerical analysis are shown when there is no buffer plate 4 in the structure of the second example, that is, when the pressure surface 2b of the molded body 2 is in direct contact with the pressing surface 3c of the support brick 3, and the stress distribution in the pressure surface 2b of the molded body 2 is shown. In this numerical analysis, the support brick 3 is an aluminum zircon refractory, and the molded body 2 is a zircon refractory. The support brick 3 is pressed with a horizontal load corresponding to a stress of 2 MPa in a temperature environment of 1200°C. Fig.26 In the image, as the color becomes whiter, the stress increases, and as the color becomes darker, the stress decreases. Fig.26 From the image, it can be understood that stress concentration occurs in a wider area at the corner 2bx at the lower end of the pressure-receiving surface portion 2b, and stress concentration occurs in an area narrower than the corner 2bx at the lower end at the two corners 2by at the upper end.

[0117] In contrast, Fig.15The results of numerical analysis are shown for the second example, that is, when a buffer plate 4 is interposed between the pressure surface 2b of the formed body 2 and the pressing surface 3c of the support brick 3, and the stress distribution in the pressure surface 2b is shown. In this numerical analysis, the buffer plate 4 is a platinum plate with a thickness of 2 mm, the support brick 3 is an aluminum zircon refractory, the formed body 2 is a zircon refractory, and the support brick 3 is pressed with a horizontal load corresponding to a stress of 2 MPa in a temperature environment of 1200°C. According to Fig.15 From the image, it can be understood that the above-mentioned stress concentration does not occur at the three corners 2bx and 2by of the pressure receiving surface portion 2b.

[0118] Fig.16 1 is a side view showing the main part structure of the glass forming device 1 of the third example of the first embodiment of the present invention. As shown in the figure, the glass forming device 1 of the third example is different from the glass forming device 1 of the first example described above in that the shape of the pressure-receiving surface 2b of the forming body 2 is substantially wedge-shaped. Specifically, the shape of the pressure-receiving surface 2b in the third example is that a rectangular portion 2bd is connected to the upper part of a portion 2bc whose width direction length gradually decreases as it goes downward. Therefore, two corners 2by with an angle of 90° exist at the upper end of the pressure-receiving surface 2b. In addition, a buffer plate 4 is sandwiched between the pressure-receiving surface 2b and the pressing surface 3c, so that a gap is formed between the two corners 2by and the pressing surface 3c. It should be noted that the corner 2bz existing between the corner 2by at the upper end of the pressure-receiving surface 2b and the corner 2bx at the lower end may not form a gap between it and the pressing surface 3c. A gap is formed in the corner 2bx at the lower end of the pressure-receiving surface 2b as in the case of the first example described above. In addition, in the third example, the chamfered surfaces 2d and 3d similar to those in the second example can also be formed. The third example is the same as the first example except for the structure described here, so the common components in both examples are as follows. Fig.16 The same reference numerals are used to denote the same reference numerals and their descriptions are omitted.

[0119] Fig.17 1 is a front view showing the main part structure of a glass forming device 1 according to a fourth example of the first embodiment of the present invention. Fig.18 FIG. 2 is a side view showing the pressure receiving surface 2 b and the buffer plate 4 of the device 1. Fig.17 As shown, the glass forming device 1 of the fourth example is different from the glass forming device 1 of the first example in that the height position of the lower end of the support brick 3 is higher than the height position of the lower end of the forming body 2. Fig.18As shown, there are two corners 2bx with an angle less than 120° at the lower end of the pressure-bearing surface 2b, and stress concentration may occur at these corners 2bx. Even in this case, since a buffer plate 4 is sandwiched between the pressure-bearing surface 2b and the pressing surface 3c, gaps are formed between these corners 2bx and the pressing surface 3c, respectively, and stress concentration at these corners 2bx is alleviated. In addition, gaps are formed at the two corners 2by at the upper end of the pressure-bearing surface 2b, similarly to the case of the first example described above. It should be noted that in this fourth example, the same chamfered surfaces 2d and 3d as those in the second example described above can also be formed. This fourth example is the same as the first example described above except for the structure described here, so the common components of both are described in detail. Fig.17 as well as Fig.18 The same reference numerals are used to denote the same reference numerals and their descriptions are omitted.

[0120] <Second embodiment>

[0121] The glass forming device 1 of the second embodiment of the present invention improves the glass forming device 1 of the first embodiment described above so that the horizontal load acting from the support brick 3 to the pressure receiving surface 2b of the forming body 2 is increased. That is, the glass forming device 1 of the first embodiment described above is not sufficient in terms of durability. Therefore, first, based on the numerical analysis described in the second example of the first embodiment described above, the analysis results when the operation period of the glass forming device 1 of the second example is extended by 20 times are described.

[0122] Fig. 27 1 is a schematic longitudinal sectional front view showing the analysis result and the main part structure of the glass forming device 1 of the second example. As shown in the figure, when the operation period of the device 1 is extended by 20 times, the creep deformation of the support brick 3 progresses in the longitudinal direction under the action of the horizontal load, and as a result, the lower end of the pressing surface 3c of the support brick 3 contacts the corner 2bx of the lower end of the pressure receiving surface 2b of the forming body 2 despite the presence of the buffer plate 4. Fig.28 The stress distribution of the pressure-receiving surface 2b at this time is shown. According to the image of this figure, it can be understood that stress concentration occurs at the corner 2bx at the lower end of the pressure-receiving surface 2b. And, its stress value exceeds 2MPa. The second embodiment shown below avoids this undesirable situation.

[0123] Fig.19This is a three-dimensional view showing the main part structure of the glass forming device 1 of the first example of the second embodiment of the present invention. It should be noted that, in this figure, only the state in which the buffer plate 4 is arranged on the supporting brick 3 is shown, but the structure of the forming body 2 and the pressure-bearing surface 2b is the same as the structure in the second example of the first embodiment described above (the same applies to the second to fourth examples of the second embodiment below). As shown in the figure, in this first example, an inclined portion 3e is formed at the lower end of the pressing surface 3b of the supporting brick 3 over the entire length in the width direction, and gradually moves away from the pressure-bearing surface 2b as it goes downward. The inclined portion 3e includes the lower end of the pressing surface 3c and is opposite to the corner 2bx of the lower end of the pressure-bearing surface 2b. According to this structure, even if the creep deformation of the supporting brick 3 progresses as described above due to the operation period of the glass forming device 1 being set to 20 times, the inclined portion 3e is not as large as the lower end of the pressing surface 2b. Fig. 20 As shown, a gap T3 is formed between the lower end portion (inclined portion 3e) of the pressing surface portion 3c and the corner portion 2bx of the lower end portion of the pressure-receiving surface portion 2b. Therefore, stress concentration is not generated at the corner portion 2bx of the lower end portion of the pressure-receiving surface portion 2b. It should be noted that the shape of the inclined portion 3e may not be planar as shown in the illustration, and may be other shapes, such as a polygonal shape or a curved shape when viewed from the front, as long as it gradually moves away from the pressure-receiving surface portion 2b as it moves downward. It should be noted that an inclined portion that gradually moves away from the pressure-receiving surface portion 2b as it moves toward the outer peripheral side may also be formed in the area at the upper end portion of the pressing surface portion 3c that is opposite to the corner portion 2by at the upper end portion of the pressure-receiving surface portion 2b. The first example of the second embodiment is the same as the second example of the first embodiment described above except for the structure described here, so the common components of both are described in detail below. Fig.19 as well as Fig. 20 The same reference numerals are used to denote the same reference numerals and their descriptions are omitted.

[0124] Fig.21: is a perspective view showing the main part structure of the glass forming device 1 of the second example of the second embodiment of the present invention. As shown in the figure, in the second example, a recess 3f is formed in the width direction center part of the lower end of the pressing surface 3b of the supporting brick 3. The recess 3f includes the lower end of the pressing surface 3c and is opposite to the corner 2bx of the lower end of the pressure-receiving surface 2b. According to this structure, as in the first example of the second embodiment described above, even if the operation period of the glass forming device 1 is set to 20 times, a gap is formed between the lower end (recess 3f) of the pressing surface 3c and the corner 2bx of the lower end of the pressure-receiving surface 2b. Therefore, stress concentration does not occur at the corner 2bx of the lower end of the pressure-receiving surface 2b. It should be noted that the shape of the recess 3f may not be hemispherical as in the example, for example, it may be rectangular in side view or front view. It should be noted that a recess may also be formed in the area opposite to the corner 2by of the upper end of the pressure-receiving surface 2b in the upper end of the pressing surface 3c. The second example of the second embodiment is the same as the second example of the first embodiment except for the structure described here, so the components common to both are described in detail. Fig.21 The same reference numerals are used to denote the same reference numerals and their descriptions are omitted.

[0125] Fig. 22 This is a three-dimensional view showing the main part structure of the glass forming device 1 of the third example of the second embodiment of the present invention. As shown in the figure, in this third example, a plurality of (three in the example) buffer plates 4 are arranged in an overlapping manner between the pressing surface 3c of the supporting brick 3 and the pressure-bearing surface 2b of the forming body 2. In this case, the thickness of one buffer plate 4 is the same as the thickness already described. According to this structure, a large gap is formed between the corner 2bx at the lower end of the pressure-bearing surface 2b and the pressing surface 3c before the creep deformation of the supporting brick 3 progresses, so even if the operation period of the glass forming device 1 is set to 20 times, it becomes a state where a smaller gap still remains between the two. Therefore, stress concentration does not occur at the corner 2bx at the lower end of the pressure-bearing surface 2b. The third example of the second embodiment is the same as the second example of the first embodiment described above except for the structure described here, so the components common to both are described in detail below. Fig. 22 The same reference numerals are used to denote the same reference numerals and their descriptions are omitted.

[0126] Fig.23 1 is a perspective view showing the main part structure of a glass forming device 1 according to a fourth example of the second embodiment of the present invention. Fig.24It is an enlarged longitudinal section front view obtained by cutting the device 1 in the center in the width direction. As shown in the above figures, in this fourth example, a buffer auxiliary plate 7 is sandwiched between the pressing surface 3b of the supporting brick 3 and the buffer plate 4. The buffer auxiliary plate 7 is rectangular in shape, and extends from the two side edges 3ca of the pressing surface portion 3c to both sides in the width direction and extends downward from the lower end 3cb of the pressing surface portion 3c. In addition, the height position of the upper end of the buffer auxiliary plate 7 is the same as the height position of the lower end of the chamfered surface 3d of the supporting brick 3, and the height position of the lower end of the buffer auxiliary plate 7 is the same as the height position of the lower end of the pressing surface 3b of the supporting brick 3. According to this structure, the three corners 2bx and 2by of the pressure-receiving surface portion 2b are not in direct contact with the pressing surface portion 3c, and a gap T4 (at Fig.24 Only the corner portion 2bx at the lower end of the pressure-receiving surface portion 2b is shown in the figure.

[0127] In the fourth example of the second embodiment, when the operating period of the glass forming device 1 is set to 20 times, the buffer auxiliary plate 7 also progresses creep deformation along the length direction together with the support brick 3, so that the lower end of the buffer auxiliary plate 7 may contact the corner 2bx of the lower end of the pressure-bearing surface 2b and generate stress concentration at the corner 2bx. Therefore, the buffer auxiliary plate 7 is formed of a material having a creep strain rate smaller than that of the support brick 3. That is, under the condition of stress F / A obtained by dividing the load F that presses the support brick 3 to apply a horizontal load from the support brick 3 to the pressure-bearing surface 2b by the area A of the pressure-bearing surface 2b, when the creep strain rate of the support brick 3 is set to R and the creep strain rate of the buffer auxiliary plate 7 is set to Pa, the relationship (R / Pa)>1 is satisfied. According to this structure, even if the operating period of the glass forming device 1 is set to 20 times, Fig.25 As shown, the lower end of the buffer auxiliary plate 7 does not contact the corner 2bx of the lower end of the pressure receiving surface 2b, and stress concentration does not occur at the corner 2bx. The fourth example of the second embodiment is the same as the second example of the first embodiment described above except for the structure described here, so the common components of both are described in detail. Figure 23 to Figure 25 The same reference numerals are used to denote the same reference numerals and their descriptions are omitted.

[0128] Next, a method for producing a glass article according to an embodiment of the present invention will be described. The method includes a melting step, a transfer step, and a forming step.

[0129] The melting step is a step of generating molten glass using a melting furnace. The transferring step is a step of transferring the molten glass generated in the melting furnace to the glass forming device 1 using a feeder. Figure 2) is a process in which the molten glass transferred by the feeder overflows from the overflow trough 2x of the forming body 2, flows down the guide surfaces 2z on both sides of the width direction of the forming body 2, and then fuses at the lower end of the forming body 2 and is conveyed downward to form a glass ribbon. In addition, a glass sheet or a glass roll as a glass product is obtained from the glass ribbon.

[0130] As mentioned above, although embodiment of this invention was described, embodiment of this invention is not limited to this, Various changes can be made within the range which does not deviate from the summary of this invention.

[0131] For example, in the above embodiment, the shape of the buffer plate 4 is set to a wedge shape having missing portions 4a at three corners, but as long as gaps T1 and T2 are formed between the corners 2bx, 2by of the pressure-bearing surface 2b and the pressing surface 3c, it can also be other shapes such as circular, rectangular, diamond, elliptical, etc.

[0132] In the above embodiment, the buffer plate 4 is configured in a manner to form gaps T1 and T2 between the three corners 2bx, 2by of the pressure-receiving surface 2b and the pressing surface 3c, but it can also be configured in a manner to form a gap T1 only between the corner 2bx at the lower end of the pressure-receiving surface 2b and the pressing surface 3c.

[0133] In the above embodiment, when chamfered surfaces 2d and 3d are formed above the pressure-receiving surface 2b and above the pressing surface 3c, respectively, the height position of the lower end of the chamfered surface 2d on one side is made the same as the height position of the lower end of the chamfered surface 3d on the other side, but the height positions of the two may also be different.

[0134] In the above embodiment, regarding the substantially wedge-shaped pressure receiving surface 2b, Fig.16 Although an example is shown in FIG. 1 , the present invention can be similarly applied to the pressure receiving surface portion 2 b having a substantially wedge shape other than this shape.

[0135] In the above embodiment, the present invention is applied to a glass forming device that forms a glass ribbon using an overflow down-draw method, but as long as the glass forming device has a forming body and supporting bricks and a horizontal load is applied from the supporting bricks to the pressure surface of the forming body, the present invention can also be similarly applied to a glass forming device that forms a glass ribbon using other down-draw methods such as a slit down-draw method, for example.

Claims

1. A glass forming device, comprising: a forming body; a supporting brick that supports the forming body; a pressure-receiving surface portion that exists on the forming body and has a corner portion; and a pressing surface portion that exists on the supporting brick and is opposed to the pressure-receiving surface portion, wherein the glass forming device is configured such that a horizontal load is applied from the supporting brick to the pressure-receiving surface portion. The glass forming device is characterized in that: A buffer plate is interposed between the pressure receiving surface portion and the pressing surface portion, and the buffer plate is arranged so as to form a gap between a corner portion of the pressure receiving surface portion and the pressing surface portion.

2. The glass forming device according to claim 1, characterized in that: The pressure-receiving surface is in a wedge shape or a substantially wedge shape having one corner at the lower end and two corners at the upper end. The buffer plate is arranged so as to form a gap between a corner portion of the lower end portion of the pressure receiving surface portion and the pressing surface portion.

3. The glass forming device according to claim 2, characterized in that: The buffer plate is arranged so as to form gaps between the pressing surface portion and two corner portions of the upper end portion of the pressure receiving surface portion.

4. The glass forming device according to claim 3, characterized in that: The buffer plate has a wedge shape having one corner at a lower end portion and two corners at an upper end portion, and the three corners are respectively missing.

5. The glass forming device according to any one of claims 1 to 4, characterized in that: The outer contour of the buffer plate is located inside the outer contour of the pressure receiving surface portion over the entire circumference.

6. The glass forming device according to any one of claims 1 to 4, characterized in that: Under the condition of stress F / A obtained by dividing the load F pressing the support brick to apply a horizontal load to the pressure receiving surface by the area A of the pressure receiving surface, and assuming that the creep strain rate of the support brick is R and the creep strain rate of the buffer plate is P, Satisfies the relationship of (R / P)<1.

7. The glass forming device according to claim 6, characterized in that: The buffer plate is formed of a platinum group element as a main component.

8. The glass forming device according to any one of claims 1 to 4, characterized in that: The pressing surface portion has an inclined portion that gradually moves away from the pressure receiving surface portion toward the outer peripheral side, and the inclined portion faces a corner portion of the pressure receiving surface portion.

9. The glass forming device according to any one of claims 1 to 4, characterized in that: The pressing surface portion has a recessed portion, and the recessed portion faces a corner portion of the pressure receiving surface portion.

10. The glass forming device according to any one of claims 1 to 4, characterized in that: A plurality of the buffer plates are interposed between the pressure receiving surface portion and the pressing surface portion.

11. The glass forming device according to any one of claims 1 to 4, characterized in that: A buffer auxiliary plate extending from both side edges and a lower end edge of the pressing surface portion toward the outer peripheral side is interposed between the pressing surface portion and the buffer plate.

12. The glass forming device according to claim 11, characterized in that: Under the condition of stress F / A obtained by dividing the load F pressing the support brick to apply a horizontal load to the pressure receiving surface by the area A of the pressure receiving surface, and assuming that the creep strain rate of the support brick is R and the creep strain rate of the buffer auxiliary plate is Pa, The relationship of (R / Pa)>1 is satisfied.

13. The glass forming device according to any one of claims 1 to 4, characterized in that: The refractory used in the supporting brick has a compressive creep deformation of 0.3% or less when subjected to a pressure of 0.5 MPa in an atmosphere at 1400° C. for 100 hours.

14. The glass forming device according to any one of claims 1 to 4, characterized in that: The refractory used in the supporting bricks has a longitudinal dimension of 20 mm, a lateral dimension of 25 mm and a length direction of 75 mm. When a load of 2 kg is applied vertically downward to the center portion of the longitudinal direction and 100 hours have passed, the maximum deflection of the refractory sheet in the vertical direction is less than 0.5 mm when the sheet is arranged in a horizontal direction along the length direction in an atmosphere of 1300°C and supported at both ends in the length direction.

15. A method for manufacturing a glass article, characterized in that: The method for producing the glass article comprises a forming step of forming a glass ribbon from molten glass using the glass forming apparatus according to any one of claims 1 to 4.

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