JP2022158980A - Glass substrate manufacturing apparatus and pipe member - Google Patents

Abstract

To provide a glass substrate manufacturing apparatus capable of suppressing a local stress concentration in a wave shaped part having an irregularity in a radial direction of a formed pipe member.SOLUTION: A glass substrate manufacturing apparatus includes a pipe member that is composed of a material including a platinum group metal and has a peripheral shape wall part extending in an axial direction. The wall part includes at least one wave shaped part having an irregularity in a radial direction of the wall part, the irregularity being formed so as to alternatively align in the axial direction and continue in a peripheral direction. A protrusion part that has a protrusion in the radial direction of the wave shaped part has a first protrusion part with a highest protrusion height and a pair of second protrusion parts that is arranged in both sides in the radial direction of the first protrusion part and has a protrusion height lower than that of the first protrusion part. A recess part that has a recess in the radial direction of the wave shaped part has a pair of first recess parts located between the first protrusion part and the second protrusion part. In a cross-sectional plane along a plane extending in the axial direction and the radial direction, each length of the first recess parts is longer than that of the first protrusion part.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present invention relates to a tube member for processing molten glass and a glass substrate manufacturing apparatus provided with the tube member.

Glass substrates used in displays such as liquid crystal displays and organic EL displays are manufactured by melting glass raw materials and then transferring, clarifying, and homogenizing the molten glass, and then forming it into a plate. manufactured.

Tubing is used to process molten glass. The tubular member has an axially extending peripheral wall portion and is treated while the molten glass flows. As such a tube member, for example, in a fining tube for fining glass melt, an electric current is passed between a pair of electrodes provided on the wall portion with a gap therebetween to heat the fining tube, thereby heating the glass melt. to a temperature suitable for fining. In order to prevent the electrode from becoming excessively hot when the fining tube is heated in this manner, the electrode is formed in a flange shape extending protrudingly toward the outer periphery so as to dissipate heat. Further, in some cases, the clarification pipe is provided with a vent pipe that protrudes outwardly to discharge gases such as oxygen released from the molten glass during clarification.

On the other hand, a support such as firebrick is arranged around the tubular member so as to surround the wall of the tubular member. Members such as the above-mentioned flanges and ventilation pipes provided in the clarification pipe are arranged so as to extend between the refractory bricks. For this reason, when the temperature of the clarifier is raised for operation, the refractory bricks restrict the expansion of the clarifier in the axial direction and generate internal stress. Stress tends to concentrate on the connecting portion between the trachea and the clarification tube. As a result, there is a problem that a stress higher than the breaking stress is applied, cracks occur in the connection portion, and the molten glass leaks out from the crack. Moreover, even if the stress does not reach the breaking stress, there is a risk that fatigue of the fining tube will progress and the life of the fining tube will be shortened.

Conventionally, since there is a risk of buckling due to the compressive stress in the axial direction due to heat, the tube member that conveys the glass melt is provided with at least one or more projections that are continuous in the circumferential direction in the axial direction. It is known (Patent Document 1). Further, in order to compensate for the low shape rigidity of a thin thin plate structure exposed to high operating temperatures, it is known to corrugate the thin plate of the structure (Patent Document 2).

WO2004/070251 Japanese Patent Application Laid-Open No. 2002-205123

In the pipe members described in Patent Documents 1 and 2, when the thermal expansion of the pipe member is restricted and internal stress is generated in the pipe member, the stress generated in the convex portion and the corrugated portion is transferred to the convex portion and the corrugated portion. It was found that it was easy to concentrate on some areas of the part. Such local stress concentration increases the risk of breakage of the protrusions and corrugated portions, which increases the risk of molten glass leaking out from there.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a glass substrate manufacturing apparatus capable of suppressing local stress concentration in a corrugated portion having radial unevenness formed in a tubular member.

One aspect of the present invention is a glass substrate manufacturing apparatus.
The glass substrate manufacturing apparatus includes a tubular member made of a material containing a platinum group metal and having a peripheral wall extending in the axial direction,
the wall portion includes at least one corrugated portion having undulations in the radial direction of the wall portion formed alternately in the axial direction and continuous in the circumferential direction in a partial region in the axial direction;
Among the wave-shaped portions, the convex portions that are convex in the radial direction are arranged on both sides of the first convex portion in the axial direction with respect to the first convex portion having the highest convex height, and are arranged from the first convex portion. a pair of second protrusions with a low protrusion height,
The concave portion that is concave in the radial direction of the wave-shaped portion has a pair of first concave portions positioned between the first convex portion and the second convex portion,
A length of each of the first concave portions is longer than a length of the first convex portion in a cross section of the wall portion along planes extending in the axial direction and the radial direction.

It is preferable that each of the convex portion and the concave portion has a curved portion that is curved to have a radius of curvature in the cross section.

In the cross section, it is preferable that the length of the curved portion of the first concave portion is longer than the length of the curved portion of the first convex portion.

When the curved portion is referred to as the first curved portion, the first concave portion has, in the cross section,
a flat portion linearly extending in a direction parallel to the axial direction;
a second curved portion positioned to sandwich the flat portion between the first curved portion;
In the cross section, it is preferable that the total length of the curved portion and the flat portion is longer than the length of the curved portion of the first convex portion.

Preferably, the curvature radius R1 of the curved portion of the first convex portion is equal to or smaller than the curvature radius R2 of the curved portion of the first concave portion.

Preferably, the curvature radius R1 of the curved portion of the first convex portion is equal to or smaller than the curvature radius R3 of the curved portion of the second convex portion.

It is preferable that the height H2 of the second protrusion is 1.2 to 1.6 times the height H1 of the first protrusion.

The tube member processes molten glass inside the wall,
at least one projecting member connected to the wall so as to extend outwardly from the wall and functioning during the treatment;
It is preferable to further include supports arranged around the pipe member so as to support the wall portion and sandwich the protruding member from both sides in the axial direction.

A plurality of the projecting members are provided,
The axial distance between the corrugated portion and the projecting member positioned closest to the corrugated portion among the projecting members is less than 10% of the distance between the two adjacent projecting members. , is preferred.

It is preferable that the wall portion includes a plurality of the corrugated portions formed in different regions in the axial direction.

The pipe member is formed by connecting a plurality of axially divided unit pipes,
It is preferable that one of the projecting members or one or two of the corrugated portions be formed in each of the unit tubes.

Among the unit pipes, regarding the unit pipe in which the corrugated portion is formed, the length of the corrugated portion in the axial direction is 20% or more of the length of the unit pipe in the axial direction. preferable.

Another aspect of the present invention is a tubular member,
A tubular member made of a material containing a platinum group metal and having an axially extending circumferential wall,
the wall portion includes at least one corrugated portion having undulations in the radial direction of the wall portion formed alternately in the axial direction and continuous in the circumferential direction in a partial region in the axial direction;
Among the wave-shaped portions, the convex portions that are convex in the radial direction are arranged on both sides of the first convex portion in the axial direction with respect to the first convex portion having the highest convex height, and are arranged from the first convex portion. a pair of second protrusions with a low protrusion height,
The concave portion that is concave in the radial direction of the wave-shaped portion has a pair of first concave portions positioned between the first convex portion and the second convex portion,
A tubular member, wherein the length of each of the first recesses is longer than the length of the first protrusions in a cross-section of the wall along planes extending in the axial direction and the radial direction.

According to the glass substrate manufacturing apparatus and pipe member of the above-described aspects, it is possible to suppress local stress concentration in the corrugated portion having radial unevenness formed in the pipe member.

It is a figure which shows schematic structure of a glass substrate manufacturing apparatus. It is a figure explaining the force which acts on a clarification tube. FIG. 4 is a cross-sectional view showing part of an example of a corrugated portion; It is a figure which shows the cross section which shows a part of other example of a corrugated part. It is a figure which shows the unit tube which comprises a clarification tube. It is a figure which shows the cross section which shows a part of other example of a corrugated part. (a) is a diagram showing the simulation result of the stress distribution in the conventional corrugated portion in a color scale, and (b) is a diagram showing the simulation result of the stress distribution in the corrugated portion of the present embodiment in a color scale. (a) is a diagram showing the simulation result of FIG. 7(a) in grayscale, and (b) is a diagram showing the simulation result of FIG. 7(b) in grayscale.

The glass substrate manufacturing apparatus of this embodiment will be described below.

(Overview of glass substrate manufacturing equipment)
FIG. 1 is a schematic diagram of the glass substrate manufacturing apparatus of this embodiment. The glass substrate manufacturing apparatus mainly includes a melting device 100, a forming device 200, and a cutting device 300, as shown in FIG. The melting apparatus 100 has a melting vessel 101 , a clarification tube 102 , a stirring vessel 103 , transfer tubes 104 and 105 and a glass supply tube 106 .
The melting tank 101 shown in FIG. 1 is provided with heating means such as a burner (not shown). A glass raw material to which a fining agent is added is put into the melting tank 101, and a melting process for making molten glass is performed. The molten glass melted in the melting tank 101 is supplied to the clarification tube 102 through the transfer tube 104 .
In the clarification tube 102, while flowing the glass melt MG, the temperature of the glass melt MG is adjusted, and the glass melt is clarified using the oxidation-reduction reaction of the clarifier (clarification step). Specifically, as the temperature of the glass melt in the clarification tube 102 is raised, bubbles containing oxygen, CO ₂ or SO ₂ contained in the glass melt absorb oxygen generated by the reductive reaction of the clarifier. and grow, float on the liquid surface of the molten glass, and are released into the gas phase space. After that, by lowering the temperature of the molten glass, the reducing substances produced by the reductive reaction of the refining agent undergo an oxidation reaction. As a result, gas components such as oxygen in the bubbles remaining in the glass melt are reabsorbed into the glass melt, and the bubbles disappear. The molten glass after fining is supplied to the stirring tank 103 through the transfer pipe 105 .
In the stirring tank 103, the molten glass is stirred by the stirrer 103a to perform a homogenization process. The molten glass homogenized in the stirring tank 103 is supplied to the molding device 200 through the glass supply pipe 106 .
In the forming apparatus 200, the sheet glass SG is formed from the molten glass by, for example, the overflow downdraw method, and then slowly cooled.
The cutting device 300 forms a plate-shaped glass substrate cut out from the sheet glass SG.

In this embodiment, at least one of the clarification tube 102, the transfer tubes 104 and 105, and the glass supply tube 106 among the above components of the glass substrate manufacturing apparatus is a tube member to be described later. The tube member carries out the processing of the molten glass. The fining tube 102 performs fining while the molten glass flows, as described above. The transfer pipes 104, 105 and the glass supply pipe 106 transfer the molten glass. Hereinafter, the clarification tube 102 will be described as an example of the tube member.

(clarification tube)
FIG. 2 is a schematic diagram showing the configuration of the clarification tube 102. As shown in FIG.
The clarification tube 102 is a tubular member made of a material containing a platinum group metal. Platinum group metals refer to six elements: platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), osmium (Os), and iridium (Ir). Examples of materials containing platinum group metals include materials composed of a single platinum group metal or an alloy of two or more metals. For example, platinum or platinum alloys are used.

The clarification tube 102 is a member made of a platinum group metal, and has a circumferential (cylindrical) wall portion 102a extending in the axial direction of the clarification tube 102 . Glass melt is supplied to the fining tube 102 such that a gas phase space is formed above the liquid surface of the glass melt. The molten glass is refined on the inside of wall 102a. The clarification tube 102 has a circular outer circumference in a cross section perpendicular to the axial direction. The axial direction of the clarification tube 102 means a direction parallel to the central axis of the clarification tube 102 passing through the center (circular center) of the clarification tube 102 in this cross section (horizontal direction in the figure).

The clarification tube 102 is provided with at least one projecting member. The projecting member is a member that is connected to the wall portion 102a so as to extend from the wall portion 102a to the outer peripheral side and that functions during fining. As such projecting members, the clarification pipe 102 is provided with a pair of flanges 102b and 102c and a vent pipe 102d, as shown in FIG.

The flanges 102b and 102c are disk-shaped members provided at both ends of the clarification tube 102 in the axial direction. Flanges 102b and 102c are welded to wall 102a. The flanges 102b and 102c are connected to a power supply (not shown), and when a voltage is applied between the flanges 102b and 102c by the power supply 20, a current flows through the wall portion 102a between the flanges 102b and 102c. Flow, clarification tube 102 is heated. Thus, the flanges 102b, 102c function as a pair of electrodes. By this electric heating, the clarification tube 102 is heated to, for example, about 1650° C. to 1700° C., and the molten glass MG supplied from the transfer tube 104 is heated to a temperature suitable for defoaming, for example, about 1600° C. to 1700° C. be done.

On the other hand, the flanges 102b and 102c are provided along the outer periphery of the flanges with cooling pipes (not shown) through which a coolant flows. The flanges 102b and 102c, which are heated by electric heating, are cooled.

102 d of vent pipes are pipe|tube which connects the gas phase space and the external space of the clarification pipe|tube 102 for free passage. The vent pipe 102d is welded to the wall portion 102a. The vent pipe 102d has a function of discharging gases such as oxygen, CO ₂ and SO ₂ released from the molten glass MG into the gas phase space to the external space.

The glass substrate manufacturing apparatus further includes a support 110 .
The support 110 is a structure that supports the wall portion 102 a of the clarification tube 102 . The support 110 is constructed from refractory bricks. The refractory bricks are arranged around the fining tube 102 such that the flanges 102b, 102c and vent pipe 102d extend between the refractory bricks. For this reason, the flanges 102b, 102c and the vent pipe 102d are sandwiched between refractory bricks from both sides in the axial direction.

(wavy portion)
FIG. 3 is a cross-sectional view showing part of an example corrugated portion of the clarification tube 102 . A dashed line in FIG. 3 indicates a portion corresponding to the second convex portion of the conventional corrugated portion. Except for this portion, the conventional corrugated portion is configured in the same manner as the corrugated portion of the present embodiment.
The wall 102a of the fining tube 102 includes at least one corrugation 10 in an axial partial region (an example of the region is shown in FIG. 2 by a dashed line). The corrugated portions 10 are portions of the wall portion 102a having radial unevenness formed so as to alternately line up in the axial direction and extend continuously in the circumferential direction (periphery in the circumferential direction).

The corrugations 10 have the form described below at least before being heated to the fining temperature (for example, at room temperature, i.e., 25° C.) for the production (operation) of the glass substrate, but also during operation. may have the form of

A convex portion of the corrugated portion 10 that protrudes radially outward has a first convex portion 11 and a pair of second convex portions 12 , 12 .
The first convex portion 11 is a convex portion having the highest convex height. In this specification, the convex height means the radial height with respect to the flat portion (base portion) extending in the direction parallel to the axial direction of the fining tube 102 in the portion of the wall portion 102a other than the corrugated portion 10. An example of a flat portion is the portion indicated by reference numeral 102e in FIG. 6, to which reference will be made later.
The second protrusions 12 are protrusions arranged on both sides of the first protrusion 11 in the axial direction. The second convex portion 12 has a lower convex height than the first convex portion 11 .

The concave portion of the corrugated portion 10 that is concave on the inner peripheral side in the radial direction has a pair of first concave portions 13, 13 positioned at two locations between the first convex portion 11 and the second convex portion 12. there is

In a cross section of the wall portion 102 a (hereinafter also simply referred to as a cross section) on a plane extending in the axial direction and the radial direction of the fining tube 102 , the length of each first concave portion 13 is longer than the length of the first convex portion 11 . In this specification, the length in the cross section of each part of the corrugated part means the length in the direction in which the corrugated part extends in the cross section, unless otherwise specified. It means the length along the shape of the wall (the contour of the clarifier tube). The length of at least a portion of the length includes, for example, the arc length of the curved portion described later and the length of the flat portion described later in the direction parallel to the axial direction.

When the clarification tube 102 is heated (heated) for operation, as shown in FIG. As a result, the thermal expansion of the fining tube 102 is limited and internal stresses are generated in the fining tube 102 . At this time, stress is likely to concentrate on the connecting portion between the flange or vent pipe and the clarification pipe, and distortion is likely to occur. In this embodiment, since the wall portion 102a of the clarification tube 102 is formed with the corrugated portion 10 including unevenness formed so as to be alternately arranged in the axial direction and continuous in the circumferential direction, the inside of the clarification tube 102 is formed. Part of the stress can be absorbed by being generated in the corrugated portion 10, thereby reducing the stress generated in other portions of the fining tube 102 and suppressing stress concentration at the connecting portions and the like. On the other hand, the stress generated in the corrugated part tends to concentrate in some areas of the corrugated part, and depending on the magnitude of the stress, the risk of the corrugated part breaking increases, and the risk of molten glass leaking out. increase

According to the study of the present inventor, in the corrugated portion 10,
(1) the length of the first concave portion 13 is longer than the length of the first convex portion 11;
(2) the height of the first protrusion 11 is higher than the height of the second protrusion 12;
In this case, the stress absorbed by the corrugated portion 10 tends to be dispersed in the corrugated portion 10, and local stress concentration in the corrugated portion 10 can be suppressed.

Specifically, the following was confirmed.
When the corrugated portion 10 has the form (1) above, the area where the corrugated portion 10 is likely to be distorted increases, and the stress generated in the corrugated portion 10 is easily dispersed. As a result, the magnitude of the maximum stress generated in the corrugated portion 10 can be reduced, and the risk of breakage of the corrugated portion 10 can be reduced.
When the corrugated portion 10 has the form (2) above, force is easily transmitted from the second convex portion 12 toward the first concave portion 13 , and the stress generated in the corrugated portion 10 is transferred to the first concave portion 13 . increases the effect distributed by

In this embodiment, the first protrusion 11, the first recess 13, and the second protrusion 12 are connected to each other. The connection position (boundary) between the convex portion and the concave portion is, for example, the center of the curvature radius of the corrugated portion 10 when proceeding from the concave portion to the convex portion in the cross section of the wall portion 102a. It is specified as a position moving from the inside to the outside of the corrugated portion 102 or as the center position of both ends of the portion (linear flat portion) where the radius of curvature of the corrugated portion 10 cannot be specified.

The length of the first concave portion 13 is preferably 150 to 250% of the length of the first convex portion 11 .

Each of the first protrusions 11, the second protrusions 12, and the first recesses 13 has a large effect (stress dispersion effect) of dispersing and generating stress within the corrugated portion 10 in the cross section of the wall portion 102a. Although it is preferable to have a curvilinear curved portion, it is also preferable to have a linear flat portion from the viewpoint of securing the length of the first recess 13 .
Each of the first convex portion 11, the second convex portion 12 and the first concave portion 13 may have both a curved portion and a flat portion.
Each of the first convex portion 11, the second convex portion 12, and the first concave portion 13 may have a plurality of curved portions and flat portions. When a plurality of curved portions are provided, the curved portions may have the same or different curved shapes.

The protrusion height H2 of the second protrusion 12 is preferably 1.2 to 1.6 times the protrusion height H1 of the first protrusion 11 .

According to one embodiment, the walls 102a preferably have bends 11a, 12a, 13a curved with radii of curvature R1, R3, R2 in cross-section. Such a configuration enhances the stress distribution effect. In particular, this effect can be effectively enhanced by providing the first concave portion 13 with the curved portion 13a.

The radius of curvature R1 of the curved portion 11a is, for example, about the midpoint between both ends of the curved portion 11a in the cross section of the wall portion 102a and the length of a predetermined proportion (eg, 25%) of the length of the curved portion 11a. A virtual circle with a radius is set, and the radius of curvature of an arc passing through three points, ie, the two intersections of this virtual circle and the curved portion 11a and the midpoint of the curved portion 11a, can be specified. Curvature radii R2 and R3 can also be specified in the same way.

Instead, the radius of curvature R1 of the curved portion 11a is set at a predetermined position between both ends of the curved portion 11a (for example, from the base to a height of 70% of the height of the first protrusion) in the cross section of the wall portion 102a. A virtual circle with a radius of a predetermined length (for example, 4 mm) is set with the center at the position), and an arc passing through three points: the two intersections of this virtual circle and the curved portion 11a, and the above-mentioned midpoint of the curved portion 11a. can be specified as the radius of curvature of
In this case, regarding the radius of curvature R2, the center of the virtual circle is, for example, a height position that is 60% of the height of the first protrusion from the base. The height position of 90% of the convex height of the convex portion can be specified in the same manner.

When the first recessed portion 13 is composed of the curved portion 11a, the length (valley width) of the first recessed portion 13 in the direction parallel to the axial direction is 2π・The length is preferably 0.35 to 0.6 times as long as R2.

In the cross section of the wall portion 102a, the length of the curved portion 13a of the first concave portion 13 is preferably longer than the length of the curved portion 11a of the first convex portion 11, as shown in FIG. Thereby, the stress dispersion effect can be effectively increased. In the example shown in FIG. 3, the curved portion 13a is longer than the curved portion 11a by the additional arc portion 13a1. This form is effective when the width of the portion of the wall portion 102a where the corrugated portion 10 is formed (the length in the direction parallel to the axial direction of the clarification tube 102) is limited.

FIG. 4 is a cross-sectional view showing part of another example of the corrugated portion 10. As shown in FIG. A dashed line in FIG. 4 indicates an example of a conventional corrugated portion.
When the curved portion 13a of the first recessed portion 13 is referred to as the first curved portion 13a, according to one embodiment, the first recessed portion 13, as shown in FIG. In addition, it is preferable to further have a flat portion 13b and a second curved portion 13c.
The flat portion 13 b is a portion that extends linearly in a direction parallel to the axial direction of the clarification tube 102 .
The second curved portion 13c is a portion positioned so as to sandwich the flat portion 13b between itself and the first curved portion 13a.

The length D2 of the flat portion 13b in the direction parallel to the axial direction is preferably 20 to 80% of the length of the first recess 13, more preferably 25 to 50%. If this ratio exceeds 80%, the three protrusions 11 and 12 may become independent and the stress dispersion effect may be greatly reduced. Moreover, when this ratio is less than 20%, it becomes difficult to sufficiently ensure the length of the first recess 13 . D2 is, for example, 2 to 6 mm.

The curvature radius R1 of the curved portion 11a of the first convex portion 11 is equal to the curvature radius R2 of the curved portion 13a of the first concave portion 13, or, as shown in FIGS. 3 and 4, smaller than the curvature radius R2. is preferred. That is, it is preferable that R1≦R2. As a result, the stress dispersing effect is increased, and the magnitude of the maximum stress generated in the corrugated portion 10 can be reduced. Further, when the width of the wall portion 102a is restricted as described above, making the radius of curvature R1 of the first convex portion 11 smaller than R2 makes it easier to secure the length of the first concave portion 13. FIG.

The curvature radius R1 of the curved portion 11a of the first convex portion 11 is preferably equal to or smaller than the curvature radius R3 of the curved portion 12a of the second convex portion 12 . That is, it is preferable that R1≦R3. When the width of the wall portion 102a is restricted as described above, it is effective to satisfy R3≧R1 in order to secure the length of the first concave portion 13. FIG. R1 is preferably 0.4 to 1 times as long as R3.
In the case where the width of the wall portion 102a is restricted as described above, if the first concave portion 13 has the flat portion 13b, it is preferable that the R3 of the second convex portion 12 is also small.

According to one embodiment, the height H1 of the first protrusion 11 is the sum of the radius of curvature R1 of the curved portion 11a of the first protrusion 11 and the radius of curvature R2 of the curved portion 13a of the first recess 13, R1+R2. is preferably 0.8 to 1.2 times as high, and particularly preferably H1=R1+R2. When such a relationship is satisfied, it becomes easier to adjust the size of the height H1 of the protrusion with respect to the height H2 of the protrusion so as to increase the stress dispersion effect.

As described above, when the flanges 102b, 102c and the vent pipe 102d are provided as projecting members, the corrugated portion 10 and the corrugated portion 10 closest to the projecting members 102b, 102c, 102d is preferably less than 10% of the distance between two adjacent projecting members 102b, 102c, 102d. The corrugated portion 10 is provided at a position closer to the connection portion where the stress generated in the clarification tube 102 tends to concentrate, the more the stress concentration on the connection portion can be suppressed, and the occurrence of cracks and fatigue at the connection portion. progress can be suppressed.

The wall portion 102a preferably includes a plurality of corrugated portions 10 formed in different regions in the axial direction. Since the portion that absorbs the stress generated in the clarification tube 102 increases, the effect of reducing the stress concentration on the connection portion and the like is improved.

FIG. 5 is a diagram showing a plurality of unit tubes 112 that make up the clarification tube 102. As shown in FIG.
For example, as shown in FIG. 5, the clarification tube 102 is configured by linearly connecting a plurality of axially divided unit tubes 112 . In this case, it is preferable that each of the unit pipes 112 is formed with the vent pipe 102d or one or two of the corrugated portions 10 . In FIG. 5 , illustration of unevenness of the unit tube 112 having the corrugated portion 10 is omitted. Adjacent unit pipes 112 are connected by welding. When internal stress is generated in the clarification tube 102, stress concentration is likely to occur at the connecting portion between the unit tubes 112 as well. In the clarification tube 102 of the present embodiment, part of the stress generated in the clarification tube 102 is absorbed by the corrugated portion 10 , thereby suppressing stress concentration at the connecting portion between the unit tubes 112 .

FIG. 6 is a cross-sectional view showing a part of another example of the corrugated portion.
Of the unit pipes 112 , the axial length of the corrugated portion 10 is preferably 20% or more of the axial length of the unit pipe 112 with respect to the unit pipe formed with the corrugated portion 10 . If it is less than 20%, the stress per unit length of the corrugated portion 10 increases, and the risk of breaking the corrugated portion 10 increases. In this regard, when the flat portion 13b is referred to as the second flat portion, the total length D1 of the first flat portion 15 is 80% of the axial length of the unit tube 112 as shown in FIG. It is preferably less than The first flat portions 15 are portions located on both sides of the corrugated portion 10 in addition to the corrugated portion 10 and extending in a direction parallel to the axial direction.

Preferably, the axial length of the corrugated portion 10 is 70% or more of the axial length of the unit tube 112 .

In the example shown in FIG. 6, the length D1 of the first flat portion 15 is preferably 0.3 to 1.2 times the diameter 2·R3 of the second convex portion 12 .

As shown in FIG. 6, the corrugated portion 10 preferably has slope portions 14 positioned at both ends of the corrugated portion 10 and connected to the second convex portions 12 . The slope portion 14 preferably has a curved portion 14a curved to have a radius of curvature R4. In this case, the diameter 2·R4 of the curved portion 14a is preferably 0.4 to 2 times the axial length of the connecting portion between the unit tubes 112 . Since the slope portion 14 is a portion where force is first transmitted to the corrugated portion 10 when internal stress is generated in the clarification tube 102, if the curvature radius R4 of the curved portion 14a is large, the input force will easier to concentrate on.

The curvature radius R3 of the second convex portion 12, the curvature radius R4 of the slope portion 14, and the convex height H2 of the second convex portion 12 preferably satisfy the relationship R3+R4>n·H2. n is a real number of 1-3. Furthermore, it is preferable that the magnitudes of R3 and R4 are close, for example, R3/R4 is between 0.9 and 1.1. As a result, the above-described effect of transmitting force from the second convex portion 12 toward the first convex portion 11 is enhanced.

Examples of preferred dimensions of the above-described components of corrugation 10 are shown.
H1 is 9 to 15 mm.
R1 is 4 to 8 mm.
R2 is 5-8 mm.
R3, R4 and H2 are each 4 to 8 mm.
D1 is between 15 and 25 mm.
D2 is between 2 and 8 mm.
The axial length of the corrugated portion 10 is 50-70 mm.
The axial length of the unit tube 112 is 90-120 mm.

The unit tube 112 or clarification tube 102 with corrugations 10 is placed in a hydroforming mold having, for example, a press surface machined therein to form the corrugations 10 on the wall 102a. Then, bulge processing (hydroforming) in which the wall portion is deformed by applying hydraulic pressure from the inside of the pipe, or by using a compression molding die processed so that the corrugated portion 10 is formed in the wall portion 102a. , made by compression molding.

(Experimental example)
A simulation was performed to calculate the stress distribution in the corrugated portion using a unit pipe model with various corrugated portions. In the simulation, the magnitude of the stress generated in the corrugated portion was analyzed when the temperature of the unit tube was raised to the fining temperature under the condition that thermal expansion in the axial direction was not possible. Various parameters set at the time of analysis were as follows.
・Material of unit tube: Platinum ・Axial length (width) of unit tube: 120 mm
・Thickness of unit tube: 1 mm
Temperature rise range: from 30° C. to 1650° C. Under the above parameters, the stress distribution in the corrugated portion 10 was calculated for the following five types of models.

(Model 1) A unit tube 112 having the corrugated portion 10 shown in FIG. 3 and having the corrugated portion 10 satisfying the preferred example of dimensions described above was used. D1 was set to 20 mm.
(Model 2) In model 1, a unit tube was used in which a corrugated portion (conventional example) of the form indicated by the broken line in FIG. 3 was used in the portion corresponding to the first convex portion.
(Model 3) In Model 1, a unit tube was used that had a corrugated portion (Comparative Example 1) in which the length of the portion corresponding to the first concave portion was equal to the length of the first convex portion.
(Model 4) In Model 1, a unit tube was used that had a corrugated portion (Comparative Example 2) in which the height of the portion corresponding to the first convex portion was equal to the height of the second convex portion.
(Model 5) A unit tube 112 having the corrugated portion 10 shown in FIG. 4 and having the corrugated portion 10 satisfying the above-described preferred example of dimensions was used.

From the calculated stress distribution, the maximum average stress value (maximum stress values) were compared between the models to assess the magnitude of the stress dispersion effect.

As a result of the comparison, the maximum stress value of model 1 is smaller than the maximum stress value of model 2 (conventional example), as shown in FIGS. all right. 7(a) and 8(a) are diagrams showing simulation results of the stress distribution in the corrugated portion of model 2, and FIGS. 7(b) and 8(b) are diagrams showing the corrugated portion of model 1 It is a figure which shows the simulation result of the stress distribution in. 7 and 8 are diagrams showing the same simulation results, and FIG. 8 is a diagram showing the stress distribution shown in color scale in FIG. 7 (shown in monochrome in the drawing) converted to gray scale. The bars at the left ends of FIGS. 7 and 8 showing the stress values stepwise in the vertical direction indicate that the higher the bar, the higher the stress value. The colors indicated by the bars in FIG. 7 change from dark blue at the bottom, through light blue, green, and yellow in order, to red at the top. In FIG. 7, the stress values of the corrugated portions other than the recesses show a color between dark blue and green in both Models 1 and 2, but in the recesses, Model 2 has a portion showing red. In contrast, model 1 does not have a red portion.
Moreover, it was found that the maximum stress value of model 5 is smaller than the maximum stress value of model 2 (conventional example), and that model 5 has a greater stress dispersion effect than model 2.

The maximum stress values of Models 1 and 5 are smaller than the maximum stress value of Model 3 (Comparative Example 1), and the length of the first concave portion is longer than the length of the first convex portion, thereby improving the stress dispersion effect. I understood it.
Compared to the maximum stress value of model 4 (comparative example 2), the maximum stress values of models 1 and 5 are smaller, and the height of the first convex portion is higher than the height of the second convex portion, so that the stress dispersion effect was found to improve.
Note that the maximum stress values of model 3 and model 4 were smaller than the maximum stress value of model 2.

Although the glass substrate manufacturing apparatus and tube member of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various improvements and modifications may be made without departing from the scope of the present invention. Of course.

In the above embodiment, the convex portion of the corrugated portion is convex radially outward, and the concave portion is concave radially inward. may be convex radially inward, and the recessed portion may be concave radially outward. In this form, the convex portion is convex toward the inside of the clarification tube 102 with respect to the base of the wall portion 102a, and the maximum depth position of the concave portion is, for example, located at the same height as the base of the wall portion 102a. do. It has been confirmed that the corrugated portion 10 having such a configuration also improves the stress dispersion effect.

10 Corrugated portion 11 First convex portion 11a Curved portion 12 Second convex portion 12a Curved portion 13 First concave portions 13a, 13c Curved portion 13a1 Additional arc portions 13b, 15 Flat portion 100 Melting device 101 Melting tank 102 Clarifying tube 102a Wall portion 102b, 102c flange (protruding member)
102d Vent pipe (projecting member)
102e Flat part (base part)
103 Agitation tank 103a Stirrers 104, 105 Transfer pipe 106 Glass supply pipe 110 Support 112 Unit pipe 200 Forming device 300 Cutting device MG Glass melt SG Sheet glass

Claims (13)

A tubular member made of a material containing a platinum group metal, the tubular member having an axially extending circumferential wall,
the wall portion includes at least one corrugated portion having undulations in the radial direction of the wall portion formed alternately in the axial direction and continuous in the circumferential direction in a partial region in the axial direction;
Among the wave-shaped portions, the convex portions protruding in the radial direction include a first convex portion having the highest convex height and a pair of second convex portions arranged on both sides of the first convex portion in the axial direction. and
The concave portion that is concave in the radial direction of the wave-shaped portion has a pair of first concave portions positioned between the first convex portion and the second convex portion,
A glass substrate manufacturing apparatus, wherein the length of each of the first concave portions is longer than the length of the first convex portions in a cross section of the wall portion along a plane extending in the axial direction and the radial direction. . 2. The glass substrate manufacturing apparatus according to claim 1, wherein each of said convex portion and said concave portion has a curved portion having a radius of curvature in said cross section. 3. The glass substrate manufacturing apparatus according to claim 2, wherein in the cross section, the length of the curved portion of the first concave portion is longer than the length of the curved portion of the first convex portion. When the curved portion is referred to as the first curved portion, the first concave portion has, in the cross section,
a flat portion linearly extending in a direction parallel to the axial direction;
a second curved portion positioned to sandwich the flat portion between the first curved portion;
4. The glass substrate manufacturing apparatus according to claim 2, wherein the total length of said curved portion and said flat portion in said cross section is longer than the length of said curved portion of said first convex portion. 5. Any one of claims 2 to 4, wherein the curvature radius R1 of the curved portion of the first convex portion is equal to or smaller than the curvature radius R2 of the curved portion of the first concave portion. The glass substrate manufacturing apparatus described. 6. Any one of claims 2 to 5, wherein the curvature radius R1 of the curved portion of the first convex portion is equal to or smaller than the curvature radius R3 of the curved portion of the second convex portion. The glass substrate manufacturing apparatus according to 1. The glass substrate manufacturing method according to any one of claims 1 to 6, wherein the protrusion height H2 of the second protrusion is 1.2 to 1.6 times the protrusion height H1 of the first protrusion. Device. The tube member processes molten glass inside the wall,
at least one projecting member connected to the wall so as to extend outwardly from the wall and functioning during the treatment;
8. The support according to any one of claims 1 to 7, further comprising a support that supports the wall and is arranged around the tubular member so as to sandwich the projecting member from both sides in the axial direction. Glass substrate manufacturing equipment. A plurality of the projecting members are provided,
The axial distance between the corrugated portion and the projecting member positioned closest to the corrugated portion among the projecting members is less than 10% of the distance between the two adjacent projecting members. 9. The apparatus for manufacturing a glass substrate according to claim 8. The glass substrate manufacturing apparatus according to any one of claims 1 to 9, wherein the wall portion includes a plurality of the corrugated portions formed in different regions in the axial direction. The pipe member is formed by connecting a plurality of axially divided unit pipes,
10. The glass substrate manufacturing apparatus according to claim 8, wherein one of said protruding members or one or two of said corrugated portions is formed in each of said unit tubes. 3. With respect to a unit tube in which the corrugated portion is formed, the length of the corrugated portion in the axial direction is 20% or more of the length of the unit pipe in the axial direction. 12. The glass substrate manufacturing apparatus according to 11. A tubular member made of a material containing a platinum group metal and having an axially extending circumferential wall,
the wall portion includes at least one corrugated portion having undulations in the radial direction of the wall portion formed alternately in the axial direction and continuous in the circumferential direction in a partial region in the axial direction;
Among the wave-shaped portions, the convex portions that are convex in the radial direction are arranged on both sides of the first convex portion in the axial direction with respect to the first convex portion having the highest convex height, and are arranged from the first convex portion. a pair of second protrusions with a low protrusion height,
The concave portion that is concave in the radial direction of the wave-shaped portion has a pair of first concave portions positioned between the first convex portion and the second convex portion,
A tubular member, wherein the length of each of the first recesses is longer than the length of the first protrusions in a cross-section of the wall along planes extending in the axial direction and the radial direction.

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