Glass manufacturing apparatus and glass manufacturing method

Abstract

To provide a technique for efficiently forming a buffer film in the entire width direction of the product part of a glass ribbon.SOLUTION: An apparatus for manufacturing glass includes: a plurality of conveyance rolls for conveying a beltlike glass ribbon including a product part having a uniform thickness in the center in the width direction and an ear part thicker than the product part at both ends in the width direction in the longitudinal direction of the glass ribbon; and a supply pipe for spraying a buffer on the lower surface of the glass ribbon or the outer peripheral surface of the conveyance roll. The supply pipe has a discharge port for discharging the buffer; when viewed from above, the discharge port is arranged on the outside of the product part in the width direction; and the ejection line of the discharge port faces the product part and is inclined in the axial direction of the conveyance roll.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] The glass manufacturing apparatus includes a plurality of metal rollers that transport a band-shaped glass ribbon and a nozzle that sprays sulfurous acid (SO2) gas onto the underside of the glass ribbon (see, for example, Patent Document 1). The sulfurous acid gas reacts with the constituent components of the glass to form a buffer film of sulfates such as sodium sulfate on the underside of the glass ribbon.

[0003] The nozzle shown in Figure 11b of Patent Document 1 extends parallel to the axial direction of the metal roller and ejects sulfur dioxide gas horizontally from an outlet at its tip. The nozzle shown in Figures 1 and 2a of Patent Document 1 has multiple outlets arranged at intervals in the axial direction of the metal roller and ejects sulfur dioxide gas directly upward from each outlet.

[0004] Patent Document 2 describes spraying a powder onto the lower surface of the glass ribbon instead of sulfur dioxide gas. The powder is sprayed together with a carrier gas. The powder is a compound of an alkali metal, an alkaline earth metal, or a transition metal. These compounds may be any of oxides, nitrides, sulfides, and carbides. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2002 / 051767 [Patent Document 2] Japanese Patent Application Publication No. 2016-20282 Summary of the Invention [Problem to be solved by the invention]

[0006] 11b of Patent Document 1 extends parallel to the axial direction of the metal roller and discharges sulfur dioxide gas horizontally from a discharge port at the tip of the nozzle. Therefore, a buffer film is not sufficiently formed in the vicinity of directly above the nozzle discharge port, i.e., in the vicinity of both ends in the width direction of the glass ribbon.

[0007] 1 and 2a of Patent Document 1 has a plurality of discharge ports arranged at intervals in the axial direction of the metal roller, and discharges sulfur dioxide gas directly upward from each discharge port. Since the sulfur dioxide gas hardly spreads in the width direction of the glass ribbon, a large amount of sulfur dioxide gas is used.

[0008] One aspect of the present disclosure provides a technique for efficiently forming a buffer film across the entire width of a product portion of a glass ribbon. [Means for solving the problem]

[0009] A glass manufacturing apparatus according to one aspect of the present disclosure includes a plurality of conveying rolls configured to convey a band-shaped glass ribbon, the glass ribbon having a product portion with a uniform thickness in a widthwise center and edge portions at both widthwise ends that are thicker than the product portion, in a longitudinal direction of the glass ribbon, and a supply pipe configured to spray a buffering agent onto a lower surface of the glass ribbon or an outer peripheral surface of the conveying rolls. The supply pipe has a discharge port configured to discharge the buffering agent. When viewed from above, the discharge port is disposed on the outer side of the product portion in the width direction, and a ray of radiation from the discharge port is directed toward the product portion and is inclined with respect to the axial direction of the conveying rolls. [Effects of the Invention]

[0010] According to one aspect of the present disclosure, when viewed from above, the buffering agent is discharged from the outer side of the product portion in the width direction toward the product portion at an angle relative to the axial direction of the conveying roll, so that the discharged buffering agent can be spread along the conveying roll, and a buffering film can be efficiently formed across the entire width of the product portion. [Brief explanation of the drawings]

[0011] [Figure 1]FIG. 1 is a cross-sectional view showing a glass manufacturing apparatus according to one embodiment. [Figure 2] FIG. 2 is a side view showing an example of a supply pipe and its surrounding structure. [Figure 3] FIG. 3 is a plan view showing an example of a supply pipe and its surrounding structure. [Figure 4] FIG. 4 is a cross-sectional view showing an example of a glass ribbon. [Figure 5] FIG. 5 is a side view showing an example of the range of intersections between the ray of light from the discharge portion and the lower surface of the glass ribbon. [Figure 6] FIG. 6 is a side view showing an example of the range of intersection between the ray of the discharge portion and the outer peripheral surface of the layer roll. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that in each drawing, the same or corresponding configurations are denoted by the same reference numerals, and descriptions thereof may be omitted. In each drawing, the X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other, the X-axis direction and Y-axis direction are horizontal directions, and the Z-axis direction is vertical direction. The X-axis direction is the conveying direction of the glass ribbon G, and the Y-axis direction is the width direction of the glass ribbon G. In the specification, the symbol "to" indicating a numerical range means that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0013] A glass manufacturing apparatus 1 according to one embodiment will be described with reference to Fig. 1. The glass manufacturing apparatus 1 includes, for example, a float bath 2, a dross box 3, and an annealing furnace 5, arranged from upstream to downstream in the conveyance direction of a glass ribbon G. The glass manufacturing apparatus 1 forms a glass ribbon G on molten metal M stored in the float bath 2, and pulls the formed glass ribbon G out of the float bath 2 by a plurality of lift-out rolls 31 provided inside the dross box 3 and sends it to the annealing furnace 5. The glass manufacturing apparatus 1 anneals the glass ribbon G inside the annealing furnace 5, and then cuts it into a desired size and shape. Float glass is obtained by cutting the glass ribbon G.

[0014] Float glass is, for example, alkali-free glass, aluminosilicate glass, borosilicate glass, soda-lime glass, etc. Alkali-free glass means glass that is substantially free of alkali metal oxides such as NaO and KO. Here, "substantially free of alkali metal oxides" means that the total content of alkali metal oxides is 0.1% by mass or less.

[0015] The use of float glass is not particularly limited, but for example, it is used as a cover glass for displays (e.g., liquid crystal displays or organic EL displays). When float glass is used as a cover glass, it is glass for chemical strengthening. Unlike alkali-free glass, chemical strengthening glass contains alkali metal oxides.

[0016] The thickness of float glass is selected depending on the use of the float glass. When the float glass is used as a cover glass for a display, the thickness of the float glass is, for example, 0.1 mm to 2.0 mm. When the float glass is used as a glass substrate for a display, the thickness of the float glass is, for example, 0.1 mm to 0.7 mm. When the float glass is used as a windshield for an automobile, the thickness of the float glass is, for example, 0.2 mm to 3.0 mm.

[0017] Next, referring again to FIG. 1 , the float bath 2, dross box 3, and annealing furnace 5 according to one embodiment will be described in this order. The float bath 2 includes a bath 21. The bath 21 contains molten metal M. As the molten metal M, for example, molten tin is used. In addition to molten tin, molten tin alloys and the like can also be used, and the molten metal M may be any metal as long as it has a higher density than the molten glass. The molten glass is continuously supplied onto the molten metal M, and is formed into a band-shaped glass ribbon G by utilizing the smooth liquid surface of the molten metal M.

[0018] The float bath 2 has a ceiling 22 above the bath 21. The interior of the float bath 2 is filled with a reducing gas and maintained at a pressure higher than atmospheric pressure to prevent oxidation of the molten metal M. The reducing gas is, for example, a mixed gas of nitrogen gas and hydrogen gas, containing 85% to 98.5% by volume of nitrogen gas and 1.5% to 15% by volume of hydrogen gas. The reducing gas is supplied through the joints between the bricks of the ceiling 22 and through holes in the ceiling 22.

[0019] The float bath 2 includes a heater 23 that heats the glass ribbon G. The heater 23 is suspended from, for example, a ceiling 22 and heats the glass ribbon G passing below. The heater 23 is, for example, an electric heater that is heated by electrical current. A plurality of heaters 23 are arranged in a matrix in the conveying direction and width direction of the glass ribbon G. By controlling the output of the plurality of heaters 23, it is possible to control the temperature distribution of the glass ribbon G and the thickness distribution of the glass ribbon G.

[0020] The dross box 3 is equipped with lift-out rolls 31 that lift up the glass ribbon G. A plurality of lift-out rolls 31 are arranged inside the dross box 3 at intervals in the conveying direction (X-axis direction) of the glass ribbon G. The number of lift-out rolls 31 is not particularly limited. The lift-out rolls 31 are rotationally driven by a driving device (not shown) such as a motor, and convey the glass ribbon G obliquely upward by the driving force. The axial direction of the lift-out rolls 31 is the same as the width direction (Y-axis direction) of the glass ribbon G.

[0021] The dross box 3 may be provided with a heater 37 on the ceiling to adjust the temperature of the glass ribbon G. The heater 37 may be provided not only above but also below the glass ribbon G. In the dross box 3, the temperature of the glass ribbon G is preferably (Tg-50)°C to (Tg+30)°C, with the glass transition point Tg of float glass as the reference.

[0022] The annealing furnace 5 is equipped with layer rolls 51 that transport the strip-shaped glass ribbon G in the longitudinal direction (X-axis direction) of the glass ribbon G. In this embodiment, the layer rolls 51 correspond to the transport rolls described in the claims. A plurality of layer rolls 51 are provided at intervals in the transport direction of the glass ribbon G. The number of layer rolls 51 is not particularly limited. The layer rolls 51 are rotationally driven by a driving device (not shown) such as a motor, and transport the glass ribbon G in the horizontal direction (X-axis direction) by the driving force. The axial direction of the layer rolls 51 is the same as the width direction (Y-axis direction) of the glass ribbon G.

[0023] The annealing furnace 5 anneals the glass ribbon G to a temperature equal to or lower than the strain point of the glass while conveying the glass ribbon G by annealing rolls 51. The annealing furnace 5 includes an internal heater (not shown) for adjusting the temperature of the glass ribbon G.

[0024] The annealing furnace 5 is equipped with a supply pipe 52 that sprays a buffering agent onto the lower surface of the glass ribbon G. The buffering agent reacts with the lower surface of the glass ribbon G to form a buffering film on the lower surface of the glass ribbon G. The buffering film reduces collision between the glass ribbon G and the lehr roll 51 and suppresses scratches from occurring on the lower surface of the glass ribbon G.

[0025] As the buffering agent, for example, sulfur oxide gas is used. The sulfur oxide gas may be either SO2 gas or SO3 gas. The sulfur oxide gas reacts with the lower surface of the glass ribbon G to form a buffering film on the lower surface of the glass ribbon G. The buffering film contains sulfate crystals and the like.

[0026] The supply pipe 52 may also spray a diluent gas along with the sulfur oxide gas. The diluent gas dilutes the sulfur oxide gas, reducing the amount of sulfur oxide gas used while maintaining the airflow speed. The diluent gas may be, for example, air.

[0027] The powder described in Patent Document 2 may be used as the buffer. The powder is sprayed together with a carrier gas. The powder is a compound of an alkali metal, an alkaline earth metal, or a transition metal. These compounds may be any of oxides, nitrides, sulfides, and carbides.

[0028] A band heater (not shown) may be wound around the supply pipe 52. The band heater heats the supply pipe 52, thereby heating the buffering agent and promoting the reaction between the buffering agent and the glass ribbon G.

[0029] The supply pipe 52 is disposed, for example, between the first and second layer rolls 51, 51 from the upstream side to the downstream side in the conveying direction of the glass ribbon G. The buffer film can be formed relatively upstream of the annealing furnace 5, and the occurrence of scratches on the lower surface of the glass ribbon G can be suppressed.

[0030] Although not shown, the supply pipe 52 may be disposed upstream of the first (most upstream) layer roll 51. Furthermore, although not shown, the supply pipe 52 may be disposed downstream of the second layer roll 51 in the conveying direction.

[0031] Next, the glass ribbon G will be described in detail with reference to FIG. 4, and then the supply pipe 52 will be described in detail with reference to FIGS.

[0032] As shown in FIG. 4, the glass ribbon G has a product portion G1 with a uniform thickness in the center in the width direction, and edge portions G2 thicker than the product portion G1 at both widthwise ends (only one widthwise end is shown in FIG. 4). The edge portions G2 are cut off by a cutting device after annealing. The dimension of the product portion G1 in the Y-axis direction is not particularly limited, but is, for example, 4 m to 6 m. After annealing, the product portion G1 is cut into the desired size and shape by a cutting device and used as float glass.

[0033] 2 and 3, the supply pipe 52 has a discharge port 521 that discharges the buffering agent. The discharge port 521 is provided, for example, at the tip of the supply pipe 52. An extension line of the discharge port 521 is referred to as a ray 522 of the discharge port 521. The ray 522 of the discharge port 521 represents the discharge direction of the buffering agent. The ray 522 of the discharge port 521 passes through the center of the discharge port 521.

[0034] As shown in Fig. 3, when viewed from above, discharge outlet 521 is provided on the outer side of product portion G1 in the width direction and discharges the buffer toward product portion G1. Although one discharge outlet 521 is provided on one side of product portion G1 in the width direction as shown in Fig. 3, a pair of discharge outlets may be provided on both sides of product portion G1 in the width direction.

[0035] When viewed from above, the discharge port 521 is preferably disposed on the widthwise outer side of the ear portion G2, that is, on the widthwise outer side of the glass ribbon G. This makes it possible to ensure space below the glass ribbon G. Although not shown, the discharge port 521 may also be disposed directly below the ear portion G2.

[0036] When viewed from above, a ray 522 of the discharge port 521 is directed toward the product part G1 and is inclined with respect to the axial direction (Y-axis direction) of the layer roll 51. Therefore, when viewed from above, the discharge port 521 discharges the buffering agent from the outer side of the product part G1 in the width direction toward the product part G1 at an angle with respect to the axial direction of the layer roll 51.

[0037] The buffering agent discharged from the discharge port 521 heads toward the inside in the width direction of the glass ribbon G and toward one side in the longitudinal direction of the glass ribbon G. As a result, the buffering agent discharged from the discharge port 521 heads toward the upper edge of the layer roll 51. The upper edge of the layer roll 51 is in contact with the lower surface of the glass ribbon G and is blocked by the glass ribbon G.

[0038] The buffer material discharged from the discharge port 521 changes direction without going over the upper edge of the layer roll 51 and flows in the Y-axis direction along the upper edge of the layer roll 51. As a result, the buffer material can be supplied to the entire width of the product part G1. Furthermore, by flowing the buffer material in the Y-axis direction, the position of unreacted buffer material can be displaced in the Y-axis direction, allowing the buffer material to be used efficiently and reducing the amount of buffer material used.

[0039] In Patent Document 2, a supply pipe is provided across the entire width of the product portion G1 when viewed from above. According to this embodiment, even if a supply pipe 52 is not provided across the entire width of the product portion G1 when viewed from above, the buffering agent can be supplied across the entire width of the product portion G1.

[0040] Incidentally, when viewed from above, inside the annealing furnace 5, the gas pressure decreases from the upstream side to the downstream side in the conveying direction of the glass ribbon G, and an air flow is formed in the same direction as the conveying direction of the glass ribbon G. This is to prevent oxygen gas inside the annealing furnace 5 from entering the float bath 2 and to suppress oxidation of the molten metal M.

[0041] Therefore, when viewed from above, it is preferable that the ray 522 of the discharge port 521 is inclined more downstream in the conveyance direction of the glass ribbon G as it moves inward in the width direction of the glass ribbon G. This allows the buffering agent to be distributed over the entire width direction of the product part G1 of the glass ribbon G without disturbing the overall air flow inside the annealing furnace 5.

[0042] When viewed from above, the ray 522 of the discharge port 521 may be inclined more upstream in the conveyance direction of the glass ribbon G as it moves inward in the width direction of the glass ribbon G.

[0043] For example, when the discharge outlet 521 is positioned between the kth (k is a natural number greater than or equal to 1) and (k+1)th layer rolls 51, 51 from the upstream side to the downstream side in the conveying direction of the glass ribbon G, it is preferable that the ray 522 of the discharge outlet 521 is directed toward the k+1th layer roll 51 rather than the kth layer roll 51.

[0044] When viewed from above, the inclination angle θ2 of the ray 522 of the discharge port 521 with respect to the axial direction (Y-axis direction) of the layer roll 51 is set appropriately depending on the position of the discharge port 521, and is, for example, 1° to 45°. When viewed from above, the inclination angle θ2 is 0° when the ray 522 of the discharge port 521 is parallel to the Y-axis direction.

[0045] The ray 522 of the discharge port 521 intersects, for example, the edge portion G2. In Figures 2 and 3, P is the intersection point of the ray 522 and the underside of the glass ribbon G. The buffering agent discharged from the discharge port 521 hits the edge portion G2 and then flows toward the product portion G1. Therefore, the buffering agent can be supplied to the entire width direction of the product portion G1. The ray 522 of the discharge port 521 may also intersect the boundary between the edge portion G2 and the product portion G1. Although the ray 522 of the discharge port 521 intersects the underside of the glass ribbon G in Figures 2 and 3, it may also intersect the outer peripheral surface of the layer roll 51.

[0046] 5, when viewed from the Y-axis direction, it is preferable that an intersection P1 between a ray 522 of the discharge port 521 and the lower surface of the glass ribbon G is within a range A1. The range A1 is the range from a midpoint CP between the upper end 511A of the upstream layer roll 51A and the upper end 511B of the downstream layer roll 51B to the upper end 511B of the downstream layer roll 51B.

[0047] 6, when viewed from the Y-axis direction, it is preferable that intersection P2 between ray 522 of discharge port 521 and the outer circumferential surface of downstream layer roll 51B is within range A2. Range A2 is the range from upper end 511B of downstream layer roll 51B to upstream end 512B of downstream layer roll 51B.

[0048] As shown in FIG. 2, when viewed from the axial direction of the layer roll 51, a wedge-shaped gap GP is formed between the lower surface of the glass ribbon G and the outer peripheral surface of the layer roll 51. The wedge-shaped gap GP is formed across the entire width of the glass ribbon G. The discharge port 521 discharges the buffering agent toward the wedge-shaped gap GP. The wedge-shaped gap GP can be used to spread the buffering agent across the entire width of the product portion G1.

[0049] When viewed from the axial direction of the layer roll 51, the inclination angle θ1 of the ray 522 of the discharge port 521 with respect to the conveying direction (X-axis direction) of the glass ribbon G is set appropriately depending on the position of the discharge port 521, and is, for example, 0° to 45°. When viewed from the axial direction of the layer roll 51, the inclination angle θ1 is 0° when the ray 522 of the discharge port 521 is parallel to the X-axis direction.

[0050] The supply pipe 52 has, for example, a parallel pipe 523 parallel to the axial direction of the layer roll 51 and an inclined pipe 524 extending obliquely from the parallel pipe 523, and has a discharge port 521 at the tip of the inclined pipe 524. An extension line of the inclined pipe 524 is a ray 522 of the discharge port 521.

[0051] The supply pipe 52 may have only an inclined pipe 524 as long as the ray 522 of the discharge outlet 521 can be directed in the desired direction, but by also having a parallel pipe 523, interference with the layer roll 51 can be easily avoided.

[0052] The shortest distance from the lower surface of the glass ribbon G to the discharge port 521 is not particularly limited, but may be any distance that can achieve the effects of the present invention, that is, a distance that can form a buffer film across the entire width of the product portion G1.

[0053] As shown in Fig. 3, the annealing furnace 5 may be provided with a suction nozzle 53 directly below the product portion G1 that sucks up the buffer discharged from the supply pipe 52. According to this embodiment, when viewed from above, the discharge port 521 of the supply pipe 52 is provided on the outer side of the product portion G1 in the width direction, so that the suction nozzle 53 can be installed directly below the product portion G1, and excess buffer that has not reacted with the product portion G1 can be efficiently recovered. By improving the recovery rate of the buffer, corrosion of the annealing furnace 5 by the buffer can be suppressed. The recovered buffer can also be purified or reused.

[0054] The suction nozzle 53 has a rectangular box 531 and a slit 532 opening on the top surface of the box 531. The slit 532 opens, for example, directly upward and sucks the buffering agent. The narrower the gap between the top surface of the box 531 and the bottom surface of the glass ribbon G, the higher the recovery rate of the buffering agent. However, if the gap is too narrow, there is a risk that the box 531 and the glass ribbon G may come into contact due to vibrations or the like. The box 531 is installed taking vibrations and other factors into consideration.

[0055] When viewed from above, the slits 532 are provided parallel to the width direction (Y-axis direction) of the glass ribbon G. The dimension of the slits 532 in the Y-axis direction is, for example, 70% to 130% of the dimension of the product portion G1 in the Y-axis direction. Although the slits 532 are provided only directly below the product portion G1 in FIG. 3, they may also be provided directly below the edge portions G2.

[0056] 1 , the suction nozzle 53, like the supply pipe 52, is disposed between the first and second layer rolls 51, 51 from the upstream side to the downstream side in the conveying direction of the glass ribbon G. The buffer agent discharged from the supply pipe 52 can be efficiently collected.

[0057] It is sufficient that both the supply pipe 52 and the suction nozzle 53 are disposed between the kth (k is a natural number equal to or greater than 1) and (k+1)th layer rolls 51, 51, and they may be disposed downstream of the second layer roll 51. Also, both the supply pipe 52 and the suction nozzle 53 may be disposed upstream of the first layer roll 51.

[0058] The glass manufacturing apparatus and glass manufacturing method according to the present disclosure have been described above, but the present disclosure is not limited to the above-described embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure. [Explanation of symbols]

[0059] 1. Glass manufacturing equipment 51 Layer roll (transport roll) 52 Supply Pipe 521 Discharge port 522 Line of fire G Glass ribbon G1 Product Department G2 ears

Claims

1. a plurality of conveying rolls that convey a band-shaped glass ribbon in a longitudinal direction of the glass ribbon, the glass ribbon being a product portion having a uniform thickness in a center in a width direction and having ear portions at both ends in the width direction that are thicker than the product portion; a supply pipe for spraying a buffering agent onto a lower surface of the glass ribbon or an outer peripheral surface of the conveying roll, the supply pipe has a discharge port for discharging the buffer agent, When viewed from above, the discharge port is disposed on the outer side of the product portion in the width direction, and a ray of radiation from the discharge port is directed toward the product portion or the outer peripheral surface of the transport roll and is inclined with respect to the axial direction of the transport roll, When viewed from the axial direction of the transport roll, a wedge-shaped gap is formed between the lower surface of the glass ribbon and the outer peripheral surface of the transport roll, The discharge port discharges the buffer toward the wedge-shaped gap.

2. The glass manufacturing apparatus according to claim 1 , wherein, when viewed from above, the ray of radiation from the discharge port is inclined toward a downstream side in a conveying direction of the glass ribbon as it moves toward an inner side in a width direction of the glass ribbon.

3. The glass manufacturing apparatus according to claim 1 or 2, wherein the ray of light from the discharge port intersects with the ear portion or a boundary between the ear portion and the product portion.

4. The glass manufacturing apparatus according to any one of claims 1 to 3, wherein the discharge port is disposed on an outer side of the edge portion in the width direction when viewed from above.

5. 5. The glass manufacturing apparatus according to claim 1, wherein the supply pipe includes a parallel pipe parallel to an axial direction of the transport roll and an inclined pipe extending obliquely from the parallel pipe, and the discharge port is provided at a tip of the inclined pipe.

6. The glass manufacturing apparatus according to any one of claims 1 to 5, further comprising a suction nozzle for sucking the buffer agent, located immediately below the product portion.

7. The glass manufacturing apparatus according to any one of claims 1 to 6, wherein the buffering agent is sulfur oxide gas.

8. A glass manufacturing method comprising: using the glass manufacturing apparatus according to any one of claims 1 to 7 to transport the glass ribbon; and spraying the buffer onto a lower surface of the glass ribbon or an outer peripheral surface of the transport roll.

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