Melting furnace and method for manufacturing glass article

Abstract

This melting furnace 1, which generates molten glass Gm by heating and melting a glass raw material, comprises: an arched ceiling wall 3c; a ceiling bearing brick 3d that supports an end surface 3ca of the ceiling wall 3c; a holding tool 5 that holds the ceiling bearing brick 3d; and a support 4 that supports the holding tool 5.

Description

Melting furnace and method for manufacturing glass articles

[0001] The present invention relates to a melting furnace and a method for producing a glass article using the same.

[0002] As is well known, glass articles such as glass plates, glass tubes, and glass fibers are produced by heating and melting glass raw materials in a melting furnace to produce molten glass, and then molding the molten glass into a predetermined shape.

[0003] A melting furnace generally comprises a melting tank for producing and storing molten glass, and an upper structure for covering the space above the melting tank.

[0004] The upper structure of the melting furnace may include an arched ceiling wall, as disclosed in, for example, Patent Document 1.

[0005] The document also discloses that the ends (both ends) of the arched ceiling wall (1a) are held by L-shaped holders (8) attached to the supports (3a) (see Figure 1 of the document).

[0006] The document also discloses that the holder (8) is made of a material such as steel SS400 (see paragraph 0039 of the document).

[0007] Japanese Patent Application Laid-Open No. 2008-1538

[0008] However, as disclosed in Patent Document 1, if the ends of an arched ceiling wall made of firebricks or other refractory materials are directly held by holders made of steel or other metal, the ends of the ceiling wall are prone to damage, which causes a problem in that the ceiling wall cannot be stably supported for a long period of time.

[0009] In view of the above, the present invention has as its technical object to stably support an arched ceiling wall for a long period of time.

[0010] (1) A first aspect of the present invention, which has been invented to solve the above-mentioned problems, is a melting furnace for heating and melting glass raw materials to produce molten glass, characterized in that it comprises an arched ceiling wall, ceiling support bricks that support the end faces of the ceiling wall, holders that hold the ceiling support bricks, and supports that support the holders.

[0011] With this configuration, the end faces of the arched ceiling wall are supported by the ceiling support bricks, and the ceiling support bricks are held by holders supported by the columns, making the ends of the ceiling wall less susceptible to damage. This makes it possible to stably support the arched ceiling wall for a long period of time.

[0012] (2) In the configuration of (1) above, the holder may have a lower support portion that supports the ceiling support brick from below and a side support portion that supports the ceiling support brick from the side, the end face of the ceiling wall abuts the support surface of the ceiling support brick, the abutting surface of the end face with the support surface is an inclined surface that is inclined at the same angle as the support surface, and the holder may be configured to receive a force that rotates the ceiling support brick downward around the corner of the ceiling support brick that corresponds to the corner between the lower support portion and the side support portion as its center.

[0013] In this way, even if the wall portion located below the ceiling support brick is removed, for example, during repair or inspection of the melting furnace, the ceiling support brick will not rotate downward around the corner. Therefore, if the retainer is configured to be fixed to the support column as described below when the wall portion is removed, the ceiling wall will remain supported by the ceiling support brick and the retainer. This prevents the ceiling wall from collapsing. As a result, when the melting furnace is restarted after repair or inspection, the ceiling wall can be reused as is.

[0014] (3) In the configuration of (1) above, the holder may be supported by a support so as to be movable up and down.

[0015] In this way, even if the wall portion located below the ceiling support brick expands or contracts in the vertical direction due to the effects of heat, the retaining device moves up and down in response, so the ceiling support brick can be held in place at all times.

[0016] (4) In any of the configurations (1) to (3) above, the holder may be supported by a support pillar so as to be movable up and down at least when the melting furnace is in operation, and may be fixed to the support pillar when the wall portion located below the ceiling support brick is removed.

[0017] In this way, the holder can properly hold the ceiling wall both when the melting furnace is in operation and when the wall portion is removed.

[0018] (5) In any of the above configurations (1) to (4), the ceiling support brick may include a first brick on the ceiling wall side and a second brick on the holder side, and the first brick may be exposed in the melting furnace while the second brick is not exposed in the melting furnace.

[0019] In this way, the second brick is less susceptible to the effects of heat from inside the melting furnace, and heat conduction from the ceiling support brick to the holder and support pillars is suppressed, allowing the ceiling support brick to be properly held by the support pillars and holder for a long period of time.

[0020] (6) In the above configuration (5), the first brick may have higher heat resistance and / or corrosion resistance than the second brick.

[0021] This arrangement makes it possible to prevent early deterioration of the first bricks that directly support the ceiling wall, thereby enabling the ceiling wall to be properly supported for a long period of time.

[0022] (7) In the above configuration (5) or (6), the second brick may have better heat retention than the first brick.

[0023] This makes it difficult for heat inside the melting furnace to escape to the outside, thereby improving energy efficiency during operation of the melting furnace.

[0024] (8) In any of the above configurations (5) to (7), the contact surfaces of the first brick and the second brick may be in contact with each other using a slippage prevention structure.

[0025] This prevents the first brick from sliding off the second brick and collapsing, and the resulting collapse of the ceiling wall.

[0026] (9) In any of the above configurations (1) to (8), the ceiling support brick may have a protrusion that protrudes toward the support column.

[0027] In this way, the convex portion can be effectively used to support the ceiling support brick on the support column via the holder.

[0028] (10) In the configuration of (9) above, the holder may have a recess for receiving the protrusion.

[0029] This arrangement makes it possible to reduce the vertical dimension of the holder, making it lighter and more compact, and also enables the holder to reliably move in accordance with the vertical movement of the ceiling support brick.

[0030] (11) A second aspect of the present invention, which has been invented to solve the above-mentioned problems, is a method for manufacturing a glass article, characterized by comprising a step of producing molten glass using a melting furnace having the configuration of any one of (1) to (10) above.

[0031] This manufacturing method can also provide substantially the same effects as those of the melting furnace having any one of the configurations (1) to (10) above.

[0032] According to the present invention, it is possible to stably support an arched ceiling wall for a long period of time.

[0033] FIG. 1 is a longitudinal sectional side view showing the overall configuration of a melting furnace according to a first embodiment of the present invention. FIG. 2 is a longitudinal sectional front view of the melting furnace shown in FIG. 1 cut along line A-A. FIG. 3 is an enlarged longitudinal sectional front view showing a main portion of the upper part of a melting furnace according to a first embodiment of the present invention. FIG. 4 is an enlarged longitudinal sectional front view showing a main portion of the upper structure of a melting furnace according to a second embodiment of the present invention. FIG. 5 is an enlarged longitudinal sectional front view showing a main portion of the upper structure of a melting furnace according to a third embodiment of the present invention. FIG. 6 is an enlarged longitudinal sectional front view showing a main portion of the upper structure of a melting furnace according to a fourth embodiment of the present invention. FIG. 7 is an enlarged longitudinal sectional front view showing a main portion of the upper structure of a melting furnace according to a first modified embodiment of the present invention. FIG. 8 is an enlarged longitudinal sectional front view showing a main portion of the upper structure of a melting furnace according to a second modified embodiment of the present invention.

[0034] A melting furnace and a method for manufacturing a glass article using the same according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0035] [First Embodiment] Fig. 1 is a longitudinal side view (cross-sectional view from the side) showing a melting furnace 1 according to a first embodiment of the present invention, and Fig. 2 is a longitudinal front view (cross-sectional view from the front) of the melting furnace 1 shown in Fig. 1 taken along line A-A. As shown in these figures, the melting furnace 1 broadly comprises a melting tank 2 for producing and storing molten glass Gm, and an upper structure 3 for covering an upper space K above the melting tank 2. In the following description, the starting point of arrow F, which indicates the flow direction (the direction from the glass raw material supply side to the molten glass discharge side, described below), in Fig. 1 is referred to as the "front side," and the ending point thereof is referred to as the "rear side." Furthermore, the side indicated by arrow B in Fig. 2 is referred to as the "right side," and the side indicated by arrow C is referred to as the "left side" (the same applies to Figs. 3 to 9 ).

[0036] The melting tank 2 includes a bottom wall 2a constituting the furnace bottom and four base side walls 2b constituting the furnace sides. The four base side walls 2b are arranged to form a rectangular shape in a plan view, and are located on the front, rear, right, and left sides, respectively. The bottom wall 2a is formed of a plurality of refractory bricks. The base side wall 2b can be formed by arranging vertically elongated refractory blocks horizontally, or by arranging a plurality of refractory bricks vertically and horizontally. The bottom wall 2a may be provided with electrodes (not shown) that heat the molten glass Gm while immersed in the molten glass Gm. Instead of or in addition to the electrodes on the bottom wall 2a, electrodes may be provided on the right and left base side walls 2b. The rear base side wall 2b is provided with an outlet 1x for discharging the molten glass Gm.

[0037] The upper structure 3 includes intermediate support bricks 3a arranged above the four base side walls 2b, respectively, and upper side walls 3b arranged above the four intermediate support bricks 3a, respectively. An arched ceiling wall 3c is also arranged at the upper end of the upper structure 3. The four intermediate support bricks 3a can be formed by arranging a plurality of refractory bricks horizontally. The four upper side walls 3b can each be formed by arranging elongated refractory blocks horizontally in the vertical direction, but may also be formed by arranging a plurality of refractory bricks vertically and horizontally. A supply device (not shown) for supplying glass raw material into the melting furnace 1 is provided on the front upper side wall 3b. The ceiling wall 3c is formed by arranging a plurality of refractory bricks in an arched shape.

[0038] A plurality of vertically extending columns 4 are arranged on the exterior of the melting tank 2 and the superstructure 3, four of which are shown in Figures 1 and 2. As shown in Figure 2, each pair of columns 4 is arranged on the exterior of both the left and right sides of the melting tank 2 and the superstructure 3, and each pair of columns 4 is arranged opposite each other, as shown in Figure 1. The columns 4 can be made of shaped steel such as H-shaped steel.

[0039] As shown in Figure 2, ceiling support bricks 3d are arranged above the right and left upper side walls 3b, and the ceiling wall 3c is supported by each ceiling support brick 3d. Each ceiling support brick 3d is held by a respective holder 5. Each holder 5 is supported by a respective support column 4.

[0040] More specifically, each holder 5 is made of metal such as ordinary steel, stainless steel, or heat-resistant steel. As shown in Fig. 1, each holder 5 extends over the entire length of the superstructure 3 in the flow direction. Furthermore, as shown in the same figure, each holder 5 is supported by two columns 4.

[0041] 2, a plurality of ceiling support bricks 3d are arranged in the flow direction, and each of the plurality of ceiling support bricks 3d is held by a corresponding holder 5. Furthermore, each of the plurality of ceiling support bricks 3d is supported from below by a corresponding upper side wall 3b.

[0042] The melting furnace 1 according to this embodiment has the same configuration on the right and left sides, and is bilaterally symmetrical. Therefore, only the components on the right side of the melting furnace 1 will be described below.

[0043] Figure 3 is an enlarged longitudinal sectional front view showing the main parts of the upper structure of the melting furnace 1. As shown in the figure, the end face 3ca of the ceiling wall 3c abuts against the receiving surface 3da of the ceiling receiving brick 3d. In this case, the abutting surface 3cb of the end face 3ca with the receiving surface 3da is an inclined surface inclined at the same angle as the receiving surface 3da. The inclination angle α of this abutting surface 3cb with respect to the horizontal plane is greater than 45° and less than 70°. The lower limit of this inclination angle α is preferably greater than 50°, more preferably greater than 55°. The upper limit of this inclination angle α is preferably less than 65°.

[0044] The ceiling support brick 3d has a protrusion 3e that protrudes toward the support column 4. More specifically, the ceiling support brick 3d has a main body 3f and a protrusion 3e that protrudes from a right end surface 3fa of the main body 3f toward the support column 4. The right end surface 3fa of the main body 3f is a vertical surface. The cross section of the protrusion 3e in a vertical plane that includes a straight line parallel to the flow direction F is rectangular. The right end surface 3ea of ​​the protrusion 3e is a vertical surface.

[0045] The lower end surface 3fb of the main body 3f of the ceiling support brick 3d abuts against the upper end surface (receiving surface) 3ba of the right upper sidewall 3b. This receiving surface 3ba is a horizontal surface. The lower end surface 3eb of the convex portion 3e of the ceiling support brick 3d is located above the lower end surface 3fb of the main body 3f by a first predetermined dimension L1, but may be located at the same height as the lower end surface 3fb of the main body 3f. The upper end surface 3ec of the convex portion 3e of the ceiling support brick 3d is located below the upper end surface 3fc of the main body 3f by a second predetermined dimension L2. The second predetermined dimension L2 is longer than the first predetermined dimension L1. In this embodiment, the second predetermined dimension L2 is at least twice the length of the first predetermined dimension L1. The upper end surface 3fc of the main body 3f is a horizontal surface. The vertical dimension L3 of the main body 3f is 1.1 to 2.5 times the vertical dimension L4 of the convex portion 3e. The horizontal dimension L5 of the main body 3f is 1.5 to 5 times the horizontal dimension L6 of the protrusion 3e.

[0046] The holder 5 has a lower support portion 5a that supports the ceiling support brick 3d from below, and a side support portion 5b that supports the ceiling support brick 3d from the side. The lower support portion 5a and the side support portion 5b are integrally formed. In this embodiment, the holder 5 has an upper support portion 5c that supports the ceiling support brick 3d from above. The upper support portion 5c and the side support portion 5b are integrally formed. The side support portion 5b is a vertical plate-like portion. The upper support portion 5c and the lower support portion 5a are both horizontal plate-like portions. In this embodiment, the inner surfaces of the upper support portion 5c and the lower support portion 5a are horizontal surfaces, but they may also be tapered surfaces.

[0047] The retainer 5 supports only the protrusion 3e of the ceiling support brick 3d. Therefore, the lower support portion 5a abuts against the lower end surface 3eb of the protrusion 3e, and the side support portion 5b abuts against the right end surface 3ea of ​​the protrusion 3e. In the illustrated example, the upper support portion 5c abuts against the upper end surface 3ec of the protrusion 3e, but this abutment is not necessary. Both the lower support portion 5a and the upper support portion 5c are spaced apart from the right end surface 3fa of the main body portion 3f of the ceiling support brick 3d. The retainer 5 does not interfere with the upper side wall 3b.

[0048] The right end surface 5ba of the side support portion 5b of the holder 5 abuts against the left end surface 4a of the support column 4. In this case, at least when the melting furnace 1 is in operation, the right end surface 5ba of the side support portion 5b of the holder 5 only contacts the left end surface 4a of the support column 4. Therefore, at this time, the holder 5 is supported by the support column 4 so as to be able to move up and down. On the other hand, when the melting furnace 1 is not in operation, for example, when the upper side wall 3b is removed during repair or inspection of the melting furnace 1, the holder 5 is fixed to the support column 4.

[0049] With the above configuration, the holder 5 is configured to receive a force that rotates the ceiling support brick 3d downward, as indicated by arrow D, with the corner 3ex of the ceiling support brick 3d, which corresponds to the corner 5x between the lower support portion 5a and the side support portion 5b of the holder 5, as its center. Here, the corner 3ex of the ceiling support brick 3d is located on the protrusion 3e and includes the portion of the protrusion 3e that abuts against the lower support portion 5a. In addition, an imaginary line Lx, which indicates the direction of the force that the support surface 3da of the ceiling support brick 3d receives from the ceiling wall 3c, is configured to intersect with the side support portion 5b of the holder 5. In the illustrated example, the imaginary line Lx intersects at the bottom of the side support portion 5b, but it is sufficient that the imaginary line Lx intersects within the range from the lower end to the upper end of the side support portion 5b.

[0050] Next, the main effects of the melting furnace 1 having the above-described configuration will be described.

[0051] In the melting furnace 1, the end surface 3ca (contact surface 3cb) of the arched ceiling wall 3c is supported by the ceiling support bricks 3d, and the ceiling support bricks 3d are held by holders 5 supported by the supports 4, so the end of the ceiling wall 3c (the area around the contact surface 3cb) is less likely to be damaged. This makes it possible to stably support the arched ceiling wall 3c for a long period of time.

[0052] The ceiling wall 3c, ceiling support brick 3d, and holder 5 are configured so that the holder 5 receives a force that rotates the ceiling support brick 3d downward around a corner 3ex of the ceiling support brick 3d, which corresponds to a corner 5x between the lower support portion 5a and the side support portion 5b of the holder 5. Therefore, even if the upper side wall 3b or the base side wall 2b located below the ceiling support brick 3d is removed, for example, during repair or inspection of the melting furnace 1, the ceiling support brick 3d will not rotate downward around the corner 3ex. Moreover, at this point, the holder 5 is fixed to the support column 4. This prevents the ceiling support brick 3d from rotating downward around the corner 3ex of the ceiling support brick 3d, and the ceiling wall 3c remains supported (sandwiched) by the ceiling support brick 3d, holder 5, and support column 4. Therefore, the ceiling wall 3c will not collapse. As a result, when the melting furnace 1 is restarted after repair or inspection, the ceiling wall 3c can be reused as is.

[0053] To configure the holder 5 so that it receives the force of the ceiling support brick 3d rotating downward around the corner 3ex of the ceiling support brick 3d as its center, the imaginary line Lx should intersect with the side support portion 5b of the holder 5. Here, the imaginary line Lx indicates the direction of the force that the receiving surface 3da of the ceiling support brick 3d receives from the ceiling wall 3c. In this way, when the imaginary line Lx intersects with the side support portion 5b of the holder 5, the holder 5 can receive the force of the ceiling support brick 3d rotating downward around the corner 3ex as its center. By adjusting the direction of the imaginary line Lx and the dimensions L1 to L6 of the ceiling support brick 3d, it is possible to make the imaginary line Lx of the ceiling support brick 3d intersect with the side support portion 5b of the holder 5. The direction of the imaginary line Lx can be adjusted by changing the inclination angle α.

[0054] Since the holder 5 is supported by the support pillar 4 so as to be able to move up and down, even if the upper side wall 3b, intermediate support brick 3a, and base side wall 2b, which are located below the ceiling support brick 3d, expand or contract in the vertical direction due to the effects of heat, the holder 5 moves up and down in response to this, so that the ceiling support brick 3d can always be properly held in place.

[0055] The holder 5 is supported by the support pillars 4 so as to be able to move up and down at least when the melting furnace 1 is in operation, and is fixed to the support pillars 4 when the upper side wall 3b located below the ceiling support brick 3d is removed, so that the ceiling support brick 3d can be properly held in place at any of the above times.

[0056] The holder 5 has a recess that receives the protrusion 3e of the ceiling support brick 3d. This recess of the holder 5 is composed of an upper support portion 5c, a side support portion 5b, and a lower support portion 5a. This makes it possible to reduce the vertical dimension of the holder 5, making it lighter and more compact, and also allows the holder 5 to reliably move in response to the vertical movement of the ceiling support brick 3d.

[0057] Second Embodiment Figure 4 is a longitudinal sectional front view showing the main components of the upper structure of the melting furnace 1 according to a second embodiment. As shown in the figure, this second embodiment differs from the first embodiment in that the ceiling support brick 3d is divided into a first brick 3d1 and a second brick 3d2. The first brick 3d1 is exposed to the interior of the melting furnace 1 (upper space K), while the second brick 3d2 is not exposed to the interior of the melting furnace 1 and is covered by the first brick 3d1. This makes the second brick 3d2 less susceptible to the heat from within the melting furnace 1 than the first brick 3d1, thereby suppressing heat conduction from the second brick 3d2 to the holder 5 and the support column 4. As a result, the ceiling support brick 3d can be properly supported by the support column 4 and the holder 5 for a long period of time. The contact surfaces 3d1a, 3d2a of the first brick 3d1 and the second brick 3d2 are both inclined surfaces inclined at the same angle α in the same direction as the support surface 3da of the ceiling support brick 3d. The first brick 3d1 has better heat resistance and / or corrosion resistance than the second brick 3d2. This prevents early deterioration of the first brick 3d1 that contacts the end surface 3ca of the ceiling wall 3c, thereby enabling the ceiling wall 3c to be properly supported over a long period of time. Furthermore, the second brick 3d2 has better heat retention than the first brick. This reduces the likelihood of heat escaping from the melting furnace 1 to the outside, thereby improving energy efficiency during operation of the melting furnace 1. To meet these requirements, it is preferable to use electrocast bricks as the first brick 3d1 and mullite-based bricks as the second brick 3d2. As another example, it is preferable to use an alumina-zircon brick as the first brick 3d1 and a mullite-based brick as the second brick 3d2. Since the other configurations and effects are the same as those of the first embodiment, the main components common to both embodiments are denoted by the same reference numerals in Figure 4, and their description will be omitted.

[0058] Third Embodiment Fig. 5 is a longitudinal sectional front view showing the main components of the upper structure of the melting furnace 1 according to a third embodiment. As shown in Fig. 5, this third embodiment differs from the second embodiment in that the contact surfaces 3d1a, 3d2a of the first brick 3d1 and the second brick 3d2 are in contact with each other using a slippage prevention structure 6. The slippage prevention structure 6 includes a first step 6x on the contact surface 3d1a of the first brick 3d1 that protrudes toward the holder 5, and a second step 6y on the contact surface 3d2a of the second brick 3d2 that protrudes toward the ceiling wall 3c. The first step 6x and the second step 6y are joined together. The provision of this slippage prevention structure 6 prevents the first brick 3d1 from sliding off the second brick 3d2 and the resulting collapse of the ceiling wall 3c. The other configurations and effects are the same as those of the second embodiment described above, so the same reference numerals are used in FIG. 5 to designate the components common to both embodiments, and the description thereof will be omitted.

[0059] [Fourth Embodiment] Figure 6 is a longitudinal sectional front view showing the main components of the upper structure of the melting furnace 1 according to a fourth embodiment. As shown in Figure 6, this fourth embodiment differs from the third embodiment in that the misalignment prevention structure 6 includes a smaller inclination angle β of the contact surfaces 3d1a, 3d2a of the first brick 3d1 and the second brick 3d2 relative to the horizontal plane than the inclination angle α. This misalignment prevention structure 6 has a wedge action that prevents the first brick 3d1 from sliding off the second brick 3d2 and the resulting collapse of the ceiling wall 3c. Other configurations and effects are the same as those of the third embodiment. Therefore, the same reference numerals are used in Figure 6 to designate components common to both embodiments, and their descriptions will be omitted.

[0060] Next, a method for manufacturing a glass article according to an embodiment of the present invention will be described.

[0061] The manufacturing method includes a molten glass producing step, a transporting step, and a forming step.

[0062] The molten glass producing step is a step of producing molten glass Gm by heating and melting glass raw materials in the melting furnace 1 having the above-described configuration.

[0063] The transfer step is a step of transferring the molten glass Gm produced in the molten glass production step from the outlet path 1x (see FIG. 1 ) of the melting furnace 1 to the forming device. The transfer step may include, as necessary, a fining step of removing bubbles from the molten glass Gm in a fining tank provided on the transfer path, a stirring step of stirring the molten glass Gm in a stirring tank, and a condition adjustment step of adjusting the viscosity of the molten glass Gm to a value suitable for forming or adjusting the flow rate.

[0064] The forming step is a step of forming a glass article from the molten glass Gm transferred in the transferring step using a forming device. In this forming step, the glass article formed is a glass plate, a glass tube, a glass fiber, or the like.

[0065] Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to these, and various modifications are possible without departing from the spirit of the present invention.

[0066] For example, in the above embodiment, the ceiling support brick 3d is formed with a protrusion 3e and is supported by the retainer 5, but as shown in Fig. 7, the ceiling support brick 3d may not be formed with the protrusion 3e and may be supported by the retainer 5. In this case, too, the ceiling support brick 3d may be divided into a first brick 3d1 and a second brick 3d2 in the same manner as in the second to fourth embodiments.

[0067] In the above embodiment, only the protrusion 3e of the ceiling support brick 3d is supported by the holder 5, but as shown in Fig. 8, in addition to the protrusion 3e of the ceiling support brick 3d, the main body 3f may also be supported by the holder 5. In this case, too, the ceiling support brick 3d may be divided into a first brick 3d1 and a second brick 3d2 in the same manner as in the second to fourth embodiments.

[0068] In the above embodiment, the side support portions 5b of the holder 5 are in contact with the support pillars 4, but as shown in Fig. 9, a connecting member 7 extending toward the ceiling support brick 3d may be attached to the support pillars 4, and the holder 5 may be supported by this connecting member 7. In this case, too, the ceiling support brick 3d may be divided into a first brick 3d1 and a second brick 3d2 in the same manner as in the second to fourth embodiments.

[0069] In the above embodiment, the holder 5 includes the lower support portion 5a, the side support portions 5b, and the upper support portion 5c, but the upper support portion 5c may not be included.

[0070] In the above embodiment, the number of support columns 4 is four, but the number of support columns 4 may be five or more.

[0071] In the above embodiment, the entire end surface 3ca of the ceiling wall 3c is flush with the abutment surface 3cb, but the area of ​​the end surface 3ca other than the abutment surface 3cb does not have to be flush with the abutment surface 3cb.

[0072] In the above embodiment, no member is provided to guide the vertical movement of the holder 5, but a guide rail or the like for guiding the vertical movement of the holder 5 may be attached to the support 4.

[0073] DESCRIPTION OF SYMBOLS 1 Melting furnace 2 Melting tank 3 Upper structure 3b Upper side wall 3c Ceiling wall 3ca End face of ceiling wall 3cb Contact surface of ceiling wall 3d Ceiling support brick 3d1 First brick 3d1a Contact surface of first brick 3d2 Second brick 3d2a Contact surface of second brick 3da Receiving surface of ceiling support brick 3e Convex portion of ceiling support brick 3ex Corner portion of ceiling support brick 4 Support 5 Holder 5a Lower support portion of holder 5b Side support portion of holder 5x Corner portion between lower support portion and side support portion 6 Misalignment prevention structure Gm Molten glass Lx Virtual straight line

Claims

1. A melting furnace for heating and melting glass raw materials to produce molten glass, comprising: an arched ceiling wall; ceiling support bricks supporting end faces of the ceiling wall; a holder for holding the ceiling support brick; and a support column for supporting the holder.

2. The melting furnace described in claim 1, characterized in that the holding device has a lower support part that supports the ceiling support brick from below and a side support part that supports the ceiling support brick from the side, the end face of the ceiling wall abuts against the receiving surface of the ceiling support brick, and the abutment surface of the end face with the receiving surface is an inclined surface that is inclined at the same angle as the receiving surface, and the holding device is configured to receive a force that rotates the ceiling support brick downward around a corner of the ceiling support brick that corresponds to the corner between the lower support part and the side support part as its center.

3. A melting furnace as claimed in claim 1, characterized in that the holder is supported by the support so as to be movable up and down.

4. A melting furnace as described in any one of claims 1 to 3, characterized in that the holder is supported by the support pillar so as to be movable up and down at least when the melting furnace is in operation, and is fixed to the support pillar when the wall portion located below the ceiling support brick is removed.

5. A melting furnace as described in any one of claims 1 to 3, characterized in that the ceiling support bricks comprise a first brick on the ceiling wall side and a second brick on the holder side, the first brick being exposed within the melting furnace and the second brick not being exposed within the melting furnace.

6. A melting furnace according to claim 5, characterized in that the first brick has higher heat resistance and / or corrosion resistance than the second brick.

7. A melting furnace according to claim 5, characterized in that the second brick has better heat retention than the first brick.

8. A melting furnace as claimed in claim 5, characterized in that the contact surfaces of the first brick and the second brick are contacted with each other using a slippage prevention structure.

9. A melting furnace as described in any one of claims 1 to 3, characterized in that the ceiling support brick has a convex portion protruding toward the support column.

10. The melting furnace according to claim 9, wherein the holder has a recess for receiving the protrusion.

11. A method for producing a glass article, comprising the step of producing molten glass using the melting furnace according to any one of claims 1 to 3.

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