Patent Publication Number: US-2020299171-A1

Title: Method and device for manufacturing glass article

Description:
TECHNICAL FIELD 
     The present invention relates to a method and an apparatus for manufacturing a glass article such as a sheet glass. 
     BACKGROUND ART 
     As is well known, flat panel displays such as liquid crystal displays and OLED displays have been reduced in thickness and weight. Along with such reduction in thickness and weight, further reduction in thickness of a sheet glass to be used for the flat panel displays is also required. 
     In general, as a method for manufacturing a sheet glass to be used for flat panel displays, various forming methods such as an overflow down-draw method are used. For example, the sheet glass is formed into a thin sheet through various steps such as a melting step, a fining step, a homogenizing step, and a forming step. In Patent Literature 1, there is disclosed a manufacturing apparatus configured to perform the steps described above, which includes a melting furnace, a fining bath, a stirring bath, a forming device, and transfer pipes (glass supply pipes) configured to connect these constituents to each other and transfer a molten glass. 
     The molten glass to be transferred through the transfer pipes becomes higher in temperature. Therefore, in order to enable the transfer of the molten glass, it is required that the transfer pipes be pre-heated in advance before operation of the sheet glass manufacturing apparatus (hereinafter, this step is referred to as “pre-heating step”). In the pre-heating step, when heating is performed under a state in which the transfer pipes are coupled to each other or in which the transfer pipes and other constituents such as the fining bath are coupled, the coupling portions may be deformed due to thermal expansion (hereinafter simply referred to as “expansion”), with the result that the transfer pipes may be damaged. Therefore, in Patent Literature 1, there is disclosed a method of assembling the manufacturing apparatus after performing the pre-heating step under a state in which the transfer pipes and other constituents are separated. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP 2013-216535 A 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, with the pre-heating step in the related art, in some cases, the expansion of the transfer pipe cannot be sufficiently secured due to differences in various conditions such as a supporting structure, a heating temperature, and a heating time for the transfer pipe. When the expansion of the transfer pipe in the pre-heating step is insufficient, thermal stress is generated in the transfer pipe. In this case, in the manufacture of the glass article after assembly of the manufacturing apparatus, the transfer pipe is further expanded. Therefore, the thermal stress in the transfer pipes is increased, and there is a risk of causing damage. 
     The present invention has been made in view of the circumstances described above, and has an object to provide a manufacturing method and a manufacturing apparatus for a glass article, which is capable of sufficiently expanding a transfer pipe in a pre-heating step. 
     The present invention has been made to solve the problem described above, and provides a manufacturing method for a glass article, comprising: a pre-heating step of heating a transfer pipe; and a transfer step of causing molten glass to flow through the transfer pipe after the pre-heating step, wherein the transfer pipe comprises a main body portion having a tubular shape and a flange portion formed on an end portion of the main body portion, wherein the main body portion is retained by a refractory, and wherein, in the pre-heating step, the main body portion is heated while the flange portion is movably supported so that the flange portion is moved in accordance with extension of the main body portion. 
     According to such a configuration, in the pre-heating step, the main body portion is heated while the flange portion of the transfer pipe is supported. Thus, the flange portion being a heavy object acts like a weight so that expansion (extension) of the main body portion can be prevented from being hindered. Further, the flange portion is movably supported. Thus, frictional resistance generated when the flange portion moves in accordance with expansion of the main body portion can be reduced as much as possible. Accordingly, thermal stress generated in the transfer pipe can be reduced, and the transfer pipe can be expanded sufficiently. Therefore, also in the manufacture of the glass article after the pre-heating step, the thermal stress in the transfer pipe can be reduced, and deformation or buckling of the transfer pipe caused by the expansion can be prevented, thereby being capable of achieving a long lifetime. 
     It is desired that, in the pre-heating step, an electric wire connected to the transfer pipe be movably supported so that the electric wire is moved in accordance with the extension of the main body portion. With this, when the main body portion is expanded, the electric wire is prevented from hindering the expansion. Therefore, thermal stress generated in the transfer pipe can be further reduced in the pre-heating step, and the thermal stress in the transfer pipe can be further reduced also in manufacture of a glass article after the pre-heating step. 
     It is preferred that, in the pre-heating step, an upper portion of the flange portion be movably supported. In addition, in the pre-heating step, a configuration, in which an intermediate portion of the flange portion in an up-and-down direction is movably supported, can be adopted. In the pre-heating step, a lower portion of the flange portion may be movably supported. 
     In the pre-heating step, it is preferred that the flange portion be movably supported by a rolling member. With this, the rolling member rolls when the flange portion moves so that frictional resistance at the time of expansion of the main body portion can be reduced as much as possible. 
     In the pre-heating step, a configuration, in which the flange portion is movably supported by a rod-shaped coupling member having an upper end swingably retained and a lower end swingably coupled to the flange portion, may be adopted. 
     The present invention has been made to solve the problem described above, and provides a manufacturing device for a glass article, comprising: a transfer pipe configured to cause molten glass to flow therethrough; and a refractory configured to retain the transfer pipe, wherein the transfer pipe comprises a main body portion having a tubular shape and a flange portion formed on an end portion of the main body portion, wherein the main body portion is retained by the refractory, and wherein the manufacturing device further comprises a support device configured to support the flange portion under a state in which the flange portion is movable in accordance with extension of the main body portion. 
     According to such a configuration, in the pre-heating step, the main body portion is heated while the flange portion of the transfer pipe is supported. Thus, the flange portion being a heavy object acts like a weight so that expansion (extension) of the main body portion can be prevented from being hindered. Further, the flange portion is movably supported. Thus, frictional resistance generated when the flange portion moves in accordance with expansion of the main body portion can be reduced as much as possible. Accordingly, thermal stress generated in the transfer pipe can be reduced, and the transfer pipe can be expanded sufficiently. Therefore, also in the manufacture of the glass article after the pre-heating step, the thermal stress in the transfer pipe can be reduced, and deformation or buckling of the transfer pipe caused by the expansion can be prevented, thereby being capable of achieving a long lifetime. 
     Advantageous Effects of Invention 
     According to the present invention, the transfer pipe can be sufficiently expanded in the pre-heating step. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a side view for illustrating an overall configuration of a manufacturing device for a glass article according to a first embodiment. 
         FIG. 2  is a side view of a transfer pipe. 
         FIG. 3  is a front view of the transfer pipe. 
         FIG. 4  is aside view for illustrating a supporting structure for an electric wire. 
         FIG. 5  is a flowchart of a manufacturing method for a glass article. 
         FIG. 6  is a side view for illustrating a part of the transfer pipe in a pre-heating step. 
         FIG. 7  is a front view of a transfer pipe of a second embodiment. 
         FIG. 8  is a side view of a transfer pipe of a third embodiment. 
         FIG. 9  is a front view of the transfer pipe of  FIG. 8 . 
         FIG. 10  is a side view for illustrating a supporting structure for the electric wire. 
         FIG. 11  is a side view for illustrating the supporting structure for the electric wire. 
         FIG. 12  is a side view of a transfer pipe of a fourth embodiment. 
         FIG. 13  is a side view of a transfer pipe of a fifth embodiment. 
         FIG. 14  is a side view of a transfer pipe of a sixth embodiment. 
         FIG. 15  is a front view of the transfer pipe of  FIG. 14 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention are described below with reference to the drawings. A manufacturing method and manufacturing apparatus for a glass article according to an embodiment (first embodiment) of the present invention are illustrated in  FIG. 1  to  FIG. 6 . 
     As illustrated in  FIG. 1 , a manufacturing apparatus for a glass article according to this embodiment comprises: a melting bath  1 ; a fining bath  2 ; a homogenization bath (stirring bath)  3 ; a pot  4 ; a forming body  5 ; and glass supply passages  6   a  to  6   d  configured to connect these constituents  1  to  5  in the stated order from an upstream side. In addition thereto, the manufacturing apparatus further comprises: an annealing furnace (not shown) configured to anneal a sheet glass GR (glass article) formed by the forming body  5 ; and a cutting device (not shown) configured to cut the sheet glass GR after the annealing. 
     The melting bath  1  is a container for performing a melting step of melting loaded glass raw materials to obtain a molten glass GM. The melting bath  1  is connected to the fining bath  2  through the glass supply passage  6   a.    
     The fining bath  2  is a container for performing a fining step of, while transferring the molten glass GM, degassing the molten glass GM through the action of a fining agent or the like. The fining bath  2  is connected to the homogenization bath  3  through the glass supply passage  6   b.  The fining bath  2  of this embodiment is formed of the transfer pipe made of a platinum material (platinum or a platinum alloy). 
     The homogenization bath  3  is a container made of a platinum material for performing a step (homogenization step) of stirring the molten glass GM having been fined to homogenize the molten glass GM. The homogenization bath  3  comprises a stirrer  3   a  having a stirring blade. The homogenization bath  3  is connected to the pot  4  through the glass supply passage  6   c.    
     The pot  4  is a container for performing a state adjustment step of adjusting the state of the molten glass GM so as to be suitable for forming. The pot  4  is presented as an example of a volume part configured to adjust the viscosity and flow rate of the molten glass GM. The pot  4  is connected to the forming body  5  through the glass supply passage  6   d.    
     The forming body  5  is configured to form the molten glass GM into a preferred shape (for example, a sheet shape). In this embodiment, the forming body  5  is configured to form the molten glass GM into a sheet shape by an overflow down-draw method. Specifically, the forming body  5  has a substantially wedge shape in a sectional shape (sectional shape perpendicular to the drawing sheet of  FIG. 1 ), and has an overflow groove (not shown) formed on an upper portion thereof. 
     The forming body  5  is configured to cause the molten glass GM to overflow from the overflow groove to flow down along both side wall surfaces (side surfaces located on a front surface side and a back surface side of the drawing sheet) of the forming body  5 . The forming body  5  is configured to cause the molten glasses GM having flowed down to join each other at lower end portions of the side wall surfaces. With this, the band-shaped sheet glass GR is formed. Further, the forming body  5  may be used for performing any other down-draw method such as a slot down-draw method. 
     The band-shaped sheet glass GR obtained in such a manner is cut so that sheet glasses having a sheet shape are cut out. The sheet glass obtained as described above has a thickness of, for example, from 0.01 mm to 2 mm, and is utilized for a flat panel display, such as a liquid crystal display or an OLED display, a substrate of an OLED illumination or a solar cell, or a protective cover. A glass article according to the present invention is not limited to the sheet glass, and encompasses a glass pipe and other glass articles having various shapes. For example, when a glass pipe is to be formed, a forming device utilizing a Danner method is arranged in place of the forming body  5 . 
     As a material of the sheet glass, silicate glass or silica glass is used, borosilicate glass, soda lime glass, aluminosilicate glass, or chemically strengthened glass is preferably used, and alkali-free glass is most preferably used. The “alkali-free glass” as used herein refers to glass substantially free of an alkaline component (alkali metal oxide), and specifically refers to glass having a weight ratio of an alkaline component of 3,000 ppm or less. In the present invention, the weight ratio of the alkaline component is preferably 1,000 ppm or less, more preferably 500 ppm or less, most preferably 300 ppm or less. 
     The glass supply passages  6   a  to  6   d  are each formed of a transfer pipe  7 . As illustrated in  FIG. 2 , the transfer pipe  7  comprises a main body portion  8  and flange portions  9   a  and  9   b.  The main body portion  8  has an elongated shape and is configured to transfer the molten glass GM. The flange portions  9   a  and  9   b  are provided at end portions of the main body portion  8 , respectively. The main body portion  8  is retained by a refractory  10 , and the refractory  10  is fixed to a casing  11 . 
     The main body portion  8  is made of a platinum material (platinum or a platinum alloy) and has a tubular shape (for example, cylindrical shape). The main body portion  8  is formed so as to be longer than the refractory  10 . Therefore, the end portions of the main body portion  8  project in a longitudinal direction from end portions of the refractory  10 . 
     The flange portions  9   a  and  9   b  each have a plate shape. The flange portions  9   a  and  9   b  comprise a first flange portion  9   a  provided at one end portion of the main body portion  8  and a second flange portion  9   b  provided at another end portion of the main body portion  8 . The flange portions  9   a  and  9   b  are formed so as to surround outer peripheral surfaces at the end portions of the main body portion  8 , respectively. 
     As illustrated in  FIG. 2  and  FIG. 3 , the flange portions  9   a  and  9   b  each comprise a disc portion  12  and a plurality of projecting portions  13  to  15  projecting from the disc portion  12 . The disc portions  12  are fixed at the end portions of the main body portion  8  in the longitudinal direction and are each made of the platinum material. The projecting portions  13  to  15  comprise a first projecting portion  13 , a second projecting portion  14 , and a third projecting portion  15 . The first projecting portion  13  projects upward from an upper portion of the disc portion  12 . The second projecting portion  14  and the third projecting portion  15  project sideward from side portions of the disc portion  12 . 
     The first projecting portions  13  serve as electrode portions (terminals) configured to cause a current to flow through the main body portion  8  via the flange portions  9   a  and  9   b.  By applying a predetermined voltage to the first projecting portions  13 , the main body portion  8  is directly energized and heated. Therefore, the first projecting portions  13  are made of, for example, copper (including a copper alloy) or nickel (including a nickel alloy). 
     The first projecting portions  13  comprise first portions  13   a,  which are formed integrally with the flange portions  9   a  and  9   b,  and second portions  13   b,  which are formed integrally with end portions of the first portions  13   a.  The first portions  13   a  are rectangular plate portions projecting upward from upper portions of the flange portions  9   a  and  9   b.  The second portions  13   b  are rectangular plate portions being continuous with the first portions  13   a  at the right angle. The second portions  13   b  project from upper end portions of the first portions  13   a  in a substantially horizontal direction or along the longitudinal direction of the main body portion  8 . The second portions  13   b  each have a hole  13   c  passing through the corresponding one of the second portions  13   b  in an up-and-down direction. 
     An electric wire  16  is connected to the second portion  13   b  through intermediation of a connector. The electric wire  16  is formed of a braided wire, and is covered with an insulating material. The electric wire  16  extends in a direction intersecting with a longitudinal direction of the transfer pipe  7 . 
     The electric wire  16  is supported so as to be movable in the longitudinal direction of the transfer pipe  7  by a support member  17 . As illustrated in  FIG. 2  to  FIG. 4 , the support member  17  comprises a first support body  18  and second support bodies  19 . The first support body  18  is configured to support a lower portion of the electric wire  16 . The second support bodies  19  are configured to support an end portion of the first support body  18 . 
     The first support body  18  comprises a roller  20  and a shaft portion  21  configured to support the roller  20  so as to be rotatable. The roller  20  is a rolling element formed into a cylindrical shape. A length L of the roller  20  is set larger than a width W of the electric wire  16 . With this, the roller  20  is configured to support the electric wire  16  so as to allow movement of the electric wire  16  in a certain range when the electric wire  16  moves (slides) in the longitudinal direction of the main body portion  8  of the transfer pipe  7 . Flange portions  20   a  are formed on both end portions of the roller  20 . The shaft portion  21  is inserted through the roller  20 . The shaft portion  21  comprises an annular coupling portion  21   a  coupled to the second support body  19 . The annular coupling portion  21   a  is formed into an annular shape. 
     The second support bodies  19  are formed of, for example, a pair of long screws (threaded rods). However, the second support bodies  19  are not limited thereto, and may be formed of other various support members. Upper end portions of the second support bodies  19  are supported on the casing  11  through intermediation of fixing members  22   a  and  22   b.  The fixing members  22   a  and  22   b  are formed of a pair of nuts. Lower end portions of the second support bodies  19  each comprise an annular coupling portion  19   a  coupled to the first support body  18 . The annular coupling portion  19   a  is formed into an annular shape, and is coupled to the annular coupling portion  21   a  of the shaft portion  21  of the first support body  18 . An insulating material  19   b  is interposed between the long screw of the second support body  19  and the annular coupling portion  19   a.    
     The second projecting portion  14  of each of the flange portions  9   a  and  9   b  comprises a first portion  14   a  and a second portion  14   b.  The first portion  14   a  projects sideways from the disc portion  12 . The second portion  14   b  projects from an end portion of the first portion  14   a  toward a center portion of the transfer pipe  7  in the longitudinal direction. The second projecting portion  14  may be made of steel, or may be made of copper or nickel similarly to the first projecting portion  13 . 
     The third projecting portion  15  of each of the flange portions  9   a  and  9   b  comprises a first portion  15   a  and a second portion  15   b.  The first portion  15   a  projects in a direction opposite to the first portion  14   a  of the second projecting portion  14 . The second portion  15   b  projects from an end portion of the first portion  15   a  toward the center portion of the transfer pipe  7  in the longitudinal direction. The third projecting portion  15  may be made of steel, or may be made of copper or nickel similarly to the first projecting portion  13 . 
     The first portions  14   a  and  15   a  of the second projecting portion  14  and the third projecting portion  15  are each formed into an elongated plate shape. The first portion  14   a  of the second projecting portion  14  projects outward in the radial direction from one side portion (intermediate portion in the up-and-down direction) of the disc portion  12 . The first portion  15   a  of the third projecting portion  15  projects from another side portion of the disc portion  12  (intermediate portion in the up-and-down direction) in a direction opposite to the second projecting portion  14 . The first portions  14   a  and  15   a  of the second projecting portion  14  and the third projecting portion  15  each have a length projecting from a side surface of the casing  11 . 
     The second portions  14   b  and  15   b  of the second projecting portion  14  and the third projecting portion  15  are fixed to end portions of the first portions  14   a  and  15   a,  which project from the casing  11 , in the longitudinal direction, respectively. The second portions  14   b  and  15   b  are each formed into a plate shape, and are fixed to lower portions of end portions of the second projecting portion  14  and the third projecting portion  15 , respectively, in a posture of being parallel to the main body portion  8  of the transfer pipe  7 . 
     The refractory  10  (for example, a refractory brick) is made of a highly zirconia-based refractory, but the material is not limited thereto. The casing  11  is formed as a rectangular parallelepiped body or a cylindrical body made of steel or other metal, but the shape thereof is not limited thereto. The casing  11  is supported so that a position thereof is changeable by a carrier or the like (not shown) in a building such as a factory in which the manufacturing apparatus for a glass article is arranged. 
     A supporting material  23  configured to support the transfer pipe  7  is interposed between the refractory  10  and the main body portion  8 . The supporting material  23  of this embodiment is a bonded body which is obtained by filling powder serving as a raw material between the main body portion  8  of the transfer pipe  7  and the refractory  10 , and then diffusion-bonding the powder through heating. The “diffusion-bonding” refers to a method involving bringing the powder particles into contact with each other to bond the powder particles to each other through utilization of diffusion of atoms occurring between contact surfaces. 
     For example, a mixture of alumina powder and silica powder may be used as the powder to be the raw material of the supporting material  23 . In this case, the mixture desirably contains alumina powder having a high melting point as a main component. The configuration of the supporting material  23  is not limited to the configuration described above, in addition to alumina powder and silica powder, other various material powders such as zirconia powder and yttria powder may be used independently. Alternatively, the supporting material  23  may be configured by mixing a plurality of kinds of powders. The supporting material  23  may be formed of a refractory fiber layer, which is held in contact with an outer peripheral surface of the main body portion  8  of the transfer pipe  7 , and an unformed refractory layer, which is arranged on an outer side of the refractory fiber layer. 
     The projecting portions  13  to  15  of each of the flange portions  9   a  and  9   b  are supported by support devices  24   a  to  24   c,  respectively, so as to be movable in the longitudinal direction of the transfer pipe  7 . The support devices  24   a  to  24   c  comprise a first support device  24   a,  a second support device  24   b,  and a third support device  24   c.  The first support device  24   a  is configured to support the first projecting portion  13  of each of the flange portions  9   a  and  9   b  of the transfer pipe  7 . The second support device  24   b  is configured to support the second projecting portion  14  of each of the flange portions  9   a  and  9   b  of the transfer pipe  7 . The third support device  24   c  is configured to support the third projecting portion  15  of each of the flange portions  9   a  and  9   b  of the transfer pipe  7 . 
     The first support device  24   a  comprises a support column  25  and a rod-shaped coupling member  26 . The support column  25  is fixed to the casing  11 . The coupling member  26  connects the support column  25  and the first projecting portion  13  to each other. 
     The support column  25  is made of steel or other metal and has an elongated shape. The support column  25  has one end portion (lower end portion) fixed to the outer surface of the casing  11  by a method such as welding. The support column  25  projects upward from an upper portion of the casing  11 . 
     The support column  25  comprises a support portion  27  to which one end portion of the coupling member  26  is coupled. The support portion  27  projects from an upper end portion of the support column  25  along a horizontal direction or a longitudinal direction of the casing  11  (cylinder center direction). The support portion  27  has a hole (hereinafter referred to as “long hole”)  27   a  formed to be elongated along a projecting direction thereof. The long hole  27   a  is formed so as to pass through the support portion  27  in the up-and-down direction. Apart of each coupling member  26  is inserted through the long hole  27   a.  In addition, the support portion  27  has holes  27   b  through which the second support bodies  19  configured to support the electric wire  16  can be inserted. End portions of the second support bodies  19  are inserted through the holes  27   b,  and the support portion  27  is fastened so as to be sandwiched by the fixing members  22   a  and  22   b  configured to be threadedly engaged with the second support bodies  19  so that the second support bodies  19  are fixed to the support portion  27 . 
     The coupling member  26  comprises a first rod  28 , a second rod  29 , and an insulating member  30 . The first rod  28  is coupled to the supporting portion  27 . The second rod  29  is coupled to a corresponding one of the flange portions  9   a  and  9   b.  The insulating member  30  is provided at a midway portion of a corresponding one of the coupling member  26 . The first rod  28  is supported by the supporting portion  27 . The second rod  29  is fixed to the first projecting portion  13  of a corresponding one of the flange portions  9   a  and  9   b  by fixing members  31   a  and  31   b.    
     The first rod  28  is formed of a screw member made of metal. One end portion of the first rod  28  (upper end portion) may be fixed to the support portion  27 . Another end portion of the first rod  28  is fastened into a female thread portion of the insulating member  30 . 
     A roller  28   a,  which is configured to travel (roll) on an upper surface of the support portion  27 , is rotatably provided to an upper end portion of the first rod  28 . The roller  28   a  is a rolling member configured to follow movement of the first rod  28  that is caused in accordance with expansion of the main body portion  8  of the transfer pipe  7  when the main body portion  8  expands by heating. The roller  28   a  is held in contact with the upper surface of the support portion  27 . 
     The second rod  29  is formed of a screw member made of metal, similarly to the first rod  28 . One end portion (upper end portion) of the second rod  29  is fastened to a female thread portion of the insulating member  30 . Another end portion (lower end portion) of the second rod  29  is inserted through a hole  13   c  formed through the second portion  13   b  of the first projecting portion  13  of a corresponding one of the flange portions  9   a  and  9   b,  and is fixed to the second portion  13   b  by the fixing members  31   a  and  31   b.    
     The fixing members  31   a  and  31   b  are formed of a pair of nuts. The fixing members  31   a  and  31   b  are threadedly engaged with the second rod  29 . Under a state in which a part of the second rod  29  is inserted through the hole  13   c  formed in the second portion  13   b  of the first projecting portion  13 , the fixing members  31   a  and  31   b  are fastened so as to sandwich the second portion  13   b  of the first projecting portion  13 , thereby fixing the second rod  29  to the second portions  13   b.    
     An insulator is suitably used as the insulating member  30 . Besides the insulator, a member which is made of a synthetic rubber or any other various materials and has a rectangular parallelepiped shape or a circular column shape may be used. The insulating member  30  couples the first rod  28  and the second rod  29  to each other under a state in which the lower end portion of the first rod  28  and the upper end portion of the second rod  29  are separated apart from each other without contact therebetween. As described above, the insulating member  30  is interposed between a corresponding one of the supporting member  27  and the first projecting portion  13  under a state in which the corresponding one of the supporting member  27  of the support column  25  and the first projecting portion  13  are connected to each other by the first rod  28  and the second rod  29 . 
     The second support device  24   b  and the third support device  24   c  comprise rollers  32  and  33  serving as rolling members, and support bases  34  and  35  configured to rotatably support the rollers  32  and  33 , respectively. An outer surface of each of the rollers  32  and  33  is formed of an insulating material. The rollers  32  and  33  are held in contact with lower surfaces of the second portions  14   b  and  15   b  of the second projecting portion  14  and the third projecting portion  15  of each of the flange portions  9   a  and  9   b,  respectively. 
     The support bases  34  and  35  are configured to rotatably support the rollers  32  and  33  through intermediation of brackets  36  and  37 , respectively. The support bases  34  and  35  in this embodiment are fixed to an outer surface (side surfaces) of the casing  11 , but are not limited thereto. For example, the support bases  34  and  35  may be arranged on a floor surface of a factory or the like on which the manufacturing device is installed, and may be supported by both of the outer surface of the casing  11  and a floor surface of a factory or the like. In view of improving workability in an assembling step S 2  described later, it is preferred that the support bases  34  and  35  be fixed to the outer surface (side surfaces) of the casing  11 . 
     Now, a method of manufacturing a glass article (sheet glass) through use of the manufacturing apparatus having the configuration described above is described. As illustrated in  FIG. 5 , this method mainly comprises a pre-heating step S 1 , an assembly step S 2 , a melting step S 3 , a molten glass supply step S 4 , a forming step S 5 , an annealing step S 6 , and a cutting step S 7 . 
     In the pre-heating step S 1 , the constituents  1  to  5  and  6   a  to  6   d  of the manufacturing apparatus are increased in temperature under the state in which the constituents  1  to  5  and  6   a  to  6   d  are individually separated. In the following, as an example of the pre-heating step S 1 , description is made of a case in which the transfer pipe  7  constituting each of the glass supply passages  6   a  to  6   d  are increased in temperature. 
     In the pre-heating step S 1 , in order that the main body portion  8  of the transfer pipe  7  may be increased in temperature, a current is caused to flow through the main body portion  8  via the flange portions  9   a  and  9   b.  Through this heating, as indicated by the two-dot chain lines in  FIG. 6 , the main body portion  8  of the transfer pipe  7  expands in the longitudinal direction (axis direction) thereof. Moreover, the main body portion  8  and the flange portions  9   a  and  9   b  expand in a radial direction. 
     At this time, the supporting material  23  filled between the refractory  10  and the main body portion  8  in the casing  11  maintains a powder state, and can flow (move) in a space defined between the main body portion  8  and the refractory  10 . As described above, the powder serving as the support material  23  acts as a lubricating material. Thus, a frictional force between the main body portion  8  and the support material  23  is reduced as much as possible so that expansion of the main body portion  8  is suitably promoted. 
     Moreover, the flange portions  9   a  and  9   b  are displaced in the longitudinal direction of the main body portion  8  in response to the expansion of the main body portion  8 . At this time, the coupling members  26  of the first support device  24   a  coupled to the flange portions  9   a  and  9   b  are capable of following the displacement of the flange portions  9   a  and  9   b  with the rollers  28   a  rolling on the upper surfaces of the supporting portions  27  of the support column  25  (see the solid lines and the two-dot chain lines in  FIG. 6 ). 
     Similarly, the second portions  14   b  and  15   b  of the second projecting portion  14  and the third projecting portion  15  of each of the flange portions  9   a  and  9   b  move in a direction in which the transfer pipe  7  extends under a state in which the second portions  14   b  and  15   b  are held in contact with the rollers  32  and  33  of the second support device  24   b  and the third support device  24   c,  respectively. At this time, with rotation of the rollers  32  and  33 , the second portions  14   b  and  15   b  can move without being subjected to excessive resistance. Therefore, the support devices  24   a  to  24   c  can suitably support each of the flange portions  9   a  and  9   b  without hindering extension of the transfer pipe  7  (main body portion  8 ). 
     When the main body portion  8  reaches a predetermined temperature, and the main body portion  8  expands to a desired length, the pre-heating step S 1  is terminated, and the assembling step S 2  is executed. In the assembly step S 2 , the constituents  1  to  5  and  6   a  to  6   d  of the manufacturing apparatus, which have been heated and expanded, are coupled to one another so that the manufacturing apparatus is assembled. 
     In the melting step S 3 , the glass raw materials supplied to the melting bath  1  are heated to generate the molten glass GM. In order to shorten a start-up time of the manufacturing apparatus, the molten glass GM may be generated in the melting bath  1  in advance during or before the assembly step S 2 . 
     In the molten glass supply step S 4 , the molten glass GM in the melting bath  1  is sequentially transferred to the fining bath  2 , the homogenization bath  3 , the pot  4 , and the forming body  5  through the glass supply passages  6   a  to  6   d.  In molten glass supply step S 4 , when the molten glass GM flows through the fining bath  2 , gas (bubbles) is generated from the molten glass GM by an action of the fining agent blended in the glass raw material. This gas is discharged to the outside from the fining bath  2  (fining step). Moreover, in the homogenization bath  3 , the molten glass GM is stirred and homogenized (homogenizing step). When the molten glass GM flows through the pot  4  and the glass supply passage  6   d,  a state of the molten glass GM (for example, viscosity and flow rate) is adjusted (state adjustment step). 
     In the molten glass supply step S 4 , when the temperature of powder interposed between the refractory  10  and the main body portion  8  becomes higher, the diffusion-bonding of the powder is activated. It is only required that the heating temperature for the powder be equal to or higher than a temperature that activates the diffusion-bonding of the powder, and it is preferred that the heating temperature be 1,400° C. or higher and 1,650° C. or lower. 
     In this embodiment, the diffusion-bonding occurs between the alumina powders in the powder and between the alumina powder and the silica powder in the powder. In addition, mullite is generated from the alumina powder and the silica powder. The mullite strongly bonds the alumina powders to each other. The diffusion-bonding proceeds with time, and finally, the powder becomes one or a plurality of bonded bodies (supporting material  23 ). The supporting material  23  adheres to the main body portion  8  and the refractory  10 , which hinders the movement of the main body portion  8  relative to the refractory  10  in the molten glass supply step S 4 . With this, the main body portion  8  is fixed to the refractory  10  so as to prevent positional displacement. The supporting material  23  keeps supporting the main body portion  8  together with the refractory  10  until the manufacture of the sheet glass GR is terminated. 
     In the forming step S 5 , the molten glass GM is supplied to the forming body  5  after the molten glass supply step S 4 . The forming body  5  is configured to cause the molten glass GM to overflow from the overflow groove to flow down along the side wall surfaces of the forming body  5 . The forming body  5  is configured to cause the molten glasses GM having flowed down to join each other at lower end portions of the side wall surfaces. Thus, the band-shaped sheet glass GR is formed. 
     After that, the band-shaped sheet glass GR is subjected to the annealing step S 6  with the annealing furnace and the cutting step S 7  with the cutting device to be cut into sheet glasses having predetermined dimensions. As a result of the steps described above, a sheet glass being a glass article is completed. Alternatively, a glass roll being a glass article may be obtained by removing both ends of the sheet glass GR in a width direction in the cutting step S 7  and thereafter taking up the band-shaped sheet glass GR into a roll shape (take-up step). 
     With the manufacturing method and the manufacturing device for a glass article according to this embodiment described above, each of the flange portions  9   a  and  9   b  of the transfer pipe  7  is supported by the support devices  24   a  to  24   c.  Thus, in the pre-heating step S 1 , the flange portions  9   a  and  9   b  being heavy objects act like weights so that expansion (extension) of the main body portion  8  can be prevented from being hindered. Further, the flange portions  9   a  and  9   b  are movably supported. Thus, frictional resistance generated when the flange portions  9   a  and  9   b  move in the pre-heating step S 1  can be reduced as much as possible. Accordingly, in the pre-heating step S 1 , thermal stress generated in the transfer pipe can be reduced, and the transfer pipe  7  can be expanded sufficiently. Thus, the thermal stress generated in the transfer pipe  7  can be reduced also in the course of manufacture of a glass article (molten glass supply step S 4 ), and deformation or buckling of the transfer pipe  7  caused by the expansion can be prevented, thereby being capable of achieving a long lifetime of the transfer pipe  7 . 
       FIG. 7  is an illustration of a transfer pipe of a second embodiment. In this embodiment, the support devices  24   a  to  24   c  comprise the common support column  25 , and coupling members  26   a  to  26   c  configured to connect the support column  25  and the projecting portions  13  to  15  of each of the flange portions  9   a  and  9   b  to each other, respectively. In the following, the coupling member  26   a  of the first support device  24   a  is referred to as a first coupling member, and the coupling member  26   b  of the second support device  24   b  is referred to as a second coupling member. Further, the coupling member  26   c  of the third support device  24   c  is referred to as a third coupling member. The first coupling member  26   a  has the same configuration as that of the coupling member  26  of the first embodiment. Similarly to the first coupling member  26   a,  the second coupling member  26   b  and the third coupling member  26   c  each comprise a first rod  28  comprising a roller  28   a,  a second rod  29 , and an insulating member  30  located between the first rod  28  and the second rod  29 . 
     The support portion  27  of the support column  25  is configured to movably support the coupling members  26   a  to  26   c.  The support portion  27  has long holes  27   a  corresponding to the coupling members  26   a  to  26   c.    
     The second portion  14   b  of the second projecting portion  14  has a hole  14   c  through which the second rod  29  of the second coupling member  26   b  is inserted. The second portion  15   b  of the third projecting portion  15  has a hole  15   c  through which the second rod  29  of the third coupling member  26   c  is inserted. 
     The second coupling member  26   b  is configured to couple the support portion  27  and the second projecting portion  14  to each other in such a manner that the roller  28   a  of the second coupling member  26   b  is held in contact with the upper surface of the support portion  27 , and the second rod  29  is fixed to the second portion  14   b  of the second projecting portion  14  with fixing members  31   a  and  31   b  such as nuts. 
     Similarly, the third coupling member  26   c  is configured to couple the support portion  27  and the third projecting portion  15  to each other in such a manner that the roller  28   a  of the third coupling member  26   c  is held in contact with the upper surface of the support portion  27 , and the second rod  29  is fixed to the second portion  15   b  of the third projecting portion  15  with fixing members  31   a  and  31   b  such as nuts. 
       FIG. 8  to  FIG. 11  are illustrations of a transfer pipe of the third embodiment. In this embodiment, the support devices  24   a  to  24   c  comprise the first coupling member  26   a,  the second coupling member  26   b,  and the third coupling member  26   c  configured to couple each of the flange portions  9   a  and  9   b  and the support portion  27 , respectively. The coupling members  26   a  to  26   c  each have a rod shape as a whole. The coupling members  26   a  to  26   c  each comprise the first rod  28  coupled to the support portion  27 , the second rod  29  coupled to each of the flange portions  9   a  and  9   b,  and the insulating member  30  interposed between the first rod  28  and the second rod  29 . 
     The first rod  28  comprises an annular coupling portion  38  at an upper end portion thereof. The annular coupling portion  38  is coupled to the support portion  27 . Similar annular coupling portions  39  are fixed to the support portion  27 , and the annular coupling portion  39  and the annular coupling portion  38  of the first rod  28  are swingably coupled to each other. With this, upper ends of the coupling members  26   a  to  26   c  are swingably retained by the support portion  27 . 
     The second rod  29  comprises an annular coupling portion  40  at a lower end portion thereof. The annular coupling portion  40  is coupled to each of the projecting portions  13  to  15  of each of the flange portions  9   a  and  9   b.  The projecting portions  13  to  15  comprise annular coupling portions  41  to  43  coupled to the annular coupling portions  40  of the second rods  29 , respectively. The annular coupling portion  40  of the second rod  29  and each of the annular coupling portions  41  to  43  of the projecting portions  13  to  15  are swingably coupled to each other. With this, lower ends of the coupling members  26   a  to  26   c  are swingably coupled to each of the flange portions  9   a  and  9   b.    
     The insulating member  30  couples the first rod  28  and the second rod  29  to each other under a state in which a lower end portion of the first rod  28  and an upper end portion of the second rod  29  are separated away from each other. 
     The coupling members  26   a  to  26   c  can change a support posture of each of the flange portions  9   a  and  9   b  in accordance with expansion of the main body portion  8  when the main body portion  8  expands in the longitudinal direction in the pre-heating step Si under a state in which the coupling members  26   a  to  26   c  support each of the flange portions  9   a  and  9   b  of the transfer pipe  7 . That is, when the main body portion  8  of the transfer pipe  7  expands from the length indicated by the solid line in  FIG. 8  to the length indicated by the two-dot chain lines in  FIG. 8 , each of the flange portions  9   a  and  9   b  moves outward in the axial direction so as to follow the expansion of the main body portion  8 . In this case, the coupling members  26   a  to  26   c  allow movement of each of the flange portions  9   a  and  9   b  in an inclined posture as indicated by the two-dot chain line. 
     In this embodiment, the configuration of the support member  17  configured to support the electric wire  16  is different from that of the first embodiment. That is, the second support bodies  19  each comprise an annular coupling portion  44  at an upper end portion thereof. The annular coupling portion  44  is swingably coupled to an annular coupling portion  45  provided to the support portion  27 . With this, the support member  17  is configured to change postures of the second support bodies  19  so as to allow movement of the electric wire  16  when the electric wire  16  moves along with movement of each of the flange portions  9   a  and  9   b  in the pre-heating step S 1  (see  FIG. 11 ). 
       FIG. 12  is an illustration of a transfer pipe of the fourth embodiment. In this embodiment, each of the flange portions  9   a  and  9   b  comprises the first portion  13   a  and the second portion  13   b.  The first portion  13   a  projects downward from a lower end portion of the disc portion  12 . The second portion  13   b  projects from the first portion  13   a.  The second portion  13   b  is formed into a plate shape and is fixed to a lower end portion of the first portion  13   a.  The second portion  13   b  projects in the horizontal direction from a middle portion of the first portion  13   a  toward the center portion of the main body portion  8  in the longitudinal direction. The second portion  13   b  is fixed to the first portion  13   a  in a posture of being parallel to the longitudinal direction of the main body portion  8  of the transfer pipe  7 . In the first portion  13   a,  the electric wire  16  is connected to a portion below the second portion  13   b.    
     The first support device  24   a  configured to support the flange portion  9   a  on the right side comprises a roller  46  and a support base  47 . The roller  46  is configured to support the first projecting portion  13  of the flange portion  9   a.  The support base  47  is configured to rotatably support the roller  46 . The roller is rotatably supported on the support base  47  through intermediation of a bracket  48 . The support base  47  is installed on a floor surface of a factory or the like on which the manufacturing device is arranged. 
     Similarly to the first support device  24   a  of the first embodiment, the first support device  24   a,  which is configured to support the flange portion  9   b  on the left side, is configured to movably support the flange portion  9   b  by the coupling member  26 . However, unlike the first support device  24   a  of the first embodiment, an upper end of the coupling member  26  (second rod  29 ) is fixed to a lower surface of the casing. Further, the second portion  13   b  of the first projecting portion  13  has a long hole for causing the first rod  28  to insert therethrough, and the roller  28   a  is held in contact with a lower surface of the second portion  13   b.    
       FIG. 13  is an illustration of a transfer pipe of the fifth embodiment. This embodiment is different from the first embodiment in that the transfer pipe  7  is in an inclined posture. The transfer pipe  7  comprises the main body portion  8  and the flange portions  9   a  and  9   b.  The main body portion  8  is formed in an inclined posture. The flange portions  9   a  and  9   b  are formed on both end portions of the main body portion. The main body portion  8  is inclined so that the end portion on the first flange portion  9   a  side is located on an upper side with respect to the end portion on the second flange portion  9   b  side. It is desired that an inclination angle of the main body portion  8  with respect to the horizontal direction be 3° to 30°. 
     The first projecting portion  13  of the flange portion  9   a  on the right side comprises the first portion  13   a  and the second portion  13   b.  The first portion  13   a  projects upward from an upper end portion of the disc portion  12 . The second portion  13   b  projects from the first portion  13   a  toward the center portion of the main body portion  8  in the longitudinal direction. The second portion  13   b  of this embodiment extends horizontally, but may be inclined at the same angle as the inclination angle of the main body portion  8  so as to be parallel to the main body portion  8  of the transfer pipe  7 . The first support device  24   a  of the flange portion  9   a  has the same configuration as that of the first embodiment. In this embodiment, the distance from the support portion  27  to the second portion  13   b  becomes smaller along with movement of the flange portion  9   a  in accordance with extension of the main body portion  8 . Therefore, the length of the coupling member  26  is shortened, and a state in which the flange portion  9   a  is supported by the coupling member  26  is maintained. The length of the coupling member  26  maybe changed, for example, by changing the fastening length of the first rod  28  and/or the second rod  29  with respect to the insulating member  30 . 
     The first projecting portion  13  of the flange portion  9   b  on the left side comprises the first portion  13   a  and the second portion  13   b.  The first portion  13   a  projects downward from the lower end portion of the disc portion  12 . The second portion  13   b  projects from the first portion  13   a  toward the center portion of the main body portion  8  in the longitudinal direction. The second portion  13   b  of this embodiment is inclined at the same angle as the inclination angle of the main body portion  8  so as to be parallel to the main body portion  8  of the transfer pipe  7 , but may extend horizontally. The first support device  24   a  of the flange portion  9   b  has the same configuration as that of the fourth embodiment. The first support device  24   a  supports the second portion  13   b  of the first projecting portion  13  in a inclined posture, thereby being capable movably supporting the flange portion  9   b  without hindering expansion of the main body portion  8 . 
     In each of the flange portions  9   a  and  9   b,  the second portions  14   b  and  15   b  of the second projecting portion  14  and the third projecting portion  15  are inclined at the same angle as the inclination angle of the main body portion  8  so as to be parallel to the main body portion  8  of the transfer pipe  7 . 
       FIG. 14  and  FIG. 15  are illustrations of a transfer pipe of the sixth embodiment. This embodiment is different from the first embodiment in that pressing devices  49  to  51  configured to apply an external force to the transfer pipe  7  are provided to the outer surface of the casing  11 . 
     The pressing devices  49  to  51  are configured to apply an external force to each of the flange portions  9   a  and  9   b  of the transfer pipe  7  along the direction in which the transfer pipe  7  extends (longitudinal direction). The pressing devices  49  to  51  are provided at a plurality of positions on the casing  11 . That is, the pressing devices  49  to  51  are arranged on an outer surface of the casing  11  at positions corresponding to those of the projecting portions  13  to  15  of the flange portions  9   a  and  9   b.  The plurality of pressing devices  49  to  51  comprise first pressing devices  49 , second pressing devices  50 , and third pressing devices  51 . The first pressing devices  49  are provided at upper portions of the casing  11 . The second pressing devices  50  and the third pressing device  51  are provided at side portions of the casing  11 . 
     The pressing devices  49  to  51  each comprise a bracket  52  and a pressing member  53 . The bracket  52  is provided on an outer surface of the casing  11 . The pressing member  53  is supported by the bracket  52 . The bracket  52  has a plate shape and comprises a hole  52   a  passing therethrough along a longitudinal direction of the casing  11  (longitudinal direction of the main body portion  8 ). 
     The pressing member  53  comprises a shaft portion  53   a  and a pressing portion  53   b.  The pressing portion  53   b  is fixed at a distal end of the shaft portion  53   a.  The shaft portion  53   a  has a male thread portion, and the male thread portion is inserted through the hole  52   a  of the bracket  52 . The shaft portion  53   a  is fixed to the bracket  52  with fixing members  54   a  and  54   b.  The fixing members  54   a  and  54   b  are formed of a pair of nuts. The fixing members  54   a  and  54   b  are threadedly engaged with the male thread portion of the shaft portion  53   a.  The fixing members  54   a  and  54   b  are fastened so as to sandwich the bracket  52  so that the shaft portion  53   a  is fixed. 
     The pressing portion  53   b  is made of an insulating material and has a disc shape, but the shape of the pressing portion  53   b  is not limited to the disc shape. The pressing portion  53   b  is formed so as to approach and separate with respect to the projecting portions  13  to  15  of the flange portions  9   a  and  9   b  by a rotary action of the shaft portion  53   a.    
     In the pre-heating step S 1 , the pressing devices  49  to  51  apply an external force to each of the flange portions  9   a  and  9   b  when the expansion length of the main body portion  8  of the transfer pipe  7  is insufficient to promote expansion of the main body portion (external force application step). In the external force application step, the pressing member  53  of each of the pressing devices  49  to  51  is rotated so that the pressing portion  53   b  at a standby position separated away from each of the flange portions  9   a  and  9   b  is brought closer to each of the projecting portions  13  to  15  of each of the flange portions  9   a  and  9   b.  With this, the pressing portion  53   b  is brought into contact with one surface of each of the flange portions  9   a  and  9   b  (see the two-dot chain line in  FIG. 14 ). Then, the pressing member  53  is rotated so that the pressing portion  53   b  presses each of the projecting portions  13  to  15 . 
     With this, an external force is applied to each of the projecting portions  13  to  15 , which are provided at a plurality of positions in a circumferential direction of each of the flange portions  9   a  and  9   b,  along the direction in which the main body portion  8  extends. The external force is applied not to generate tensile stress in the main body portion  8 , but to reduce thermal stress (compression stress) of the main body portion  8  by promoting expansion of the main body portion  8 . As described above, the external force is applied to each of the projecting portions  13  to  15  so that the main body portion  8  can be reliably expanded to a desired length in accordance with pre-heating time (heating temperature) without leaving thermal stress in the main body portion  8 . 
     The present invention is not limited to the configurations of the above-mentioned embodiments. In addition, the action and effect of the present invention are not limited to those described above. The present invention may be modified in various forms within the range not departing from the spirit of the present invention. 
     In the embodiments described above, the transfer pipe  7  forming each of the glass supply passages  6   a  to  6   d  is given as an example. However, the transfer pipe  7  is not limited to such use, and the fining bath  2  may be formed of the transfer pipe  7  of the mode described above. That is, the present invention is applicable also to the fining bath  2 . 
     In the embodiments described above, the support devices  24   a  to  24   c  comprise the rollers  32 ,  33 , and  46  configured to movably support each of the flange portions  9   a  and  9   b,  respectively. However, the present invention is not limited thereto, and a roller may be integrally formed on each of the second portions  13   b  to  15   b  of the projecting portions  13  to  15  of each of the flange portions  9   a  and  9   b.  In this case, each of the support bases  34 ,  35 , and  47  of the support devices  24   a  to  24   c  has a support surface on which the roller is rollable (movable). 
     In the third embodiment described above, the coupling structures by the annular coupling portions  38  to  45  are illustrated as examples. However, the present invention is not limited thereto and can employ a structure using a hook, a hinge, or other coupling means. 
     REFERENCE SIGNS LIST 
     
         
           7  transfer pipe 
           8  main body portion 
           9   a  flange portion 
           9   b  flange portion 
           24   a  first support device 
           24   b  second support device 
           24   c  third support device 
           10  refractory 
           11  casing 
           28   a  roller (rolling member) 
           32  roller (rolling member) 
           33  roller (rolling member) 
           46  roller (rolling member) 
         S 1  pre-heating step 
         S 4  glass supply step (transfer step)