JP2006327830A - Glass manufacturing apparatus, its component and method for conducting ohmic heating of the component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow tube made of platinum or a platinum alloy, which reduces current constriction that occurs in a particular part when conducting ohmic heating of a branch pipe. <P>SOLUTION: The hollow tube made of platinum or the platinum alloy comprises a main pipe and the branch pipe connected to the main pipe, wherein the branch pipe is used for ohmic heating. The hollow tube has thick-walled parts at and near a joint between the main pipe and the branch pipe, except for at and near corners. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a hollow tube made of platinum or a platinum alloy suitable as a molten glass conduit of a glass manufacturing apparatus. The hollow tube of the present invention comprises a main tube and a branch tube joined to the main tube. The hollow tube of the present invention is used in applications where the branch tube is heated by energization.
Moreover, this invention relates to the glass manufacturing apparatus using the hollow tube of this invention.
The present invention also relates to a method for energizing and heating the hollow tube of the present invention.

  In a glass manufacturing apparatus, a hollow tube made of platinum or a platinum alloy such as platinum-gold alloy or platinum-rhodium alloy is used for a conduit through which high-temperature molten glass passes. Examples of a conduit through which molten glass passes include an outflow pipe provided to remove impurities from the glass manufacturing apparatus, and a molten glass as a mold for molding optical components such as lenses and prisms from the glass manufacturing apparatus. An outflow pipe for letting out slag, a conduit from a dissolution tank to a molding tank, and the like.

  In a glass manufacturing apparatus, since a temperature difference is not produced with the molten glass which passes through the inside, the conduit through which the molten glass passes is heated. The conduit may be heated from the outside by a heat source such as a heater. However, in the case of a hollow tube made of platinum or a platinum alloy, a current-carrying electrode is provided on the hollow tube to heat it. It is widely done. Patent Document 1 discloses a platinum heating device that can be used as a conduit for molten glass.

In a glass manufacturing apparatus, a hollow tube 100 having a branch tube as shown in FIG. 5 may be used as a conduit through which molten glass passes. A hollow tube 100 shown in FIG. 5 includes a main tube 101 and a branch tube 102 joined to the main tube 101. In the hollow tube 100 shown in FIG. 5, the branch tube 102 may be energized and heated. When the branch pipe 102 is energized and heated with the hollow pipe 100 shown in FIG. 5, an electrode (not shown) is provided at one end of the main pipe 101 and at the end of the branch pipe 102 so that current flows in the direction of the arrow. Energize.
JP-A-11-349334

When the branch tube 102 is energized and heated with the hollow tube 100 shown in FIG. 5, the current concentrates on a specific part of the hollow tube 100. In the hollow tube 100 shown in FIG. 5, when current is applied so that current flows in the direction of the arrow, the current tends to flow through the shortest path due to its characteristics. For this reason, when a current flows in the direction of the arrow, the current concentrates on the corner portion 104 located in the shortest path of the current among the joint portion 103 between the main pipe 101 and the branch pipe 102. When such current concentration occurs, the life of the hollow tube 100 is adversely affected. Further, the corner 104 is locally heated by current concentration. When local heating occurs, the hollow tube 100 may be damaged by thermal stress, or the molten glass flowing through the hollow tube 100 may be altered. Moreover, when local heating generate | occur | produces, there exists a possibility that a drift may arise in the molten glass which distribute | circulates the inside of the hollow tube 100. FIG. Generation | occurrence | production of such a drift also causes the quality change of a molten glass.
In order to solve the above-described problems, an object of the present invention is to provide a hollow tube made of platinum or a platinum alloy in which current concentration to a specific part that occurs when energizing and heating a branch tube is reduced. . The hollow tube made of platinum or platinum alloy of the present invention is suitable as a molten glass conduit of a glass production apparatus.
Another object of the present invention is to provide an apparatus for producing molten glass using the hollow tube as a conduit for molten glass.
Another object of the present invention is to provide a method for electrically heating the hollow tube.

In order to achieve the above object, the present invention comprises a main pipe and a branch pipe joined to the main pipe, and platinum or a platinum hollow pipe used for applications in which the branch pipe is energized and heated. Because
The main pipe and the branch pipe provide a hollow pipe made of platinum or a platinum alloy in which a thick portion is provided in the vicinity of a joint portion excluding a corner portion.

In the hollow tube made of platinum or platinum alloy according to the present invention, the thick portion preferably satisfies the following formulas (1) to (3).
L ₁ = 1.2d to 2.0d (1)
L ₂ = 0.2d to 1.5d (2)
t = 1.2t _{0 to} 1.5t ₀ (3)
L ₁ : Maximum length of the thick part in the main pipe (mm)
L ₂ : Maximum length of the thick part in the branch pipe (mm)
d: Outer diameter of branch pipe (mm)
t: Thickness of thick part (mm)
t ₀ : Thickness (mm) of the hollow tube other than the thick part

  In the hollow tube made of platinum or platinum alloy of the present invention, it is preferable that the branch pipe is joined so as to be orthogonal to the main pipe.

  The present invention also provides a glass manufacturing apparatus using the platinum or platinum alloy hollow tube described above as a molten glass conduit.

Further, the present invention is a method of energizing and heating a hollow tube made of platinum or a platinum alloy as described above,
Provided is a method for energizing and heating a hollow tube made of platinum or a platinum alloy, wherein a current is passed so that a current flows from the main pipe to the branch pipe.

In the hollow tube made of platinum or platinum alloy of the present invention, the current concentration at a specific site that occurs when the branch tube is energized and heated is reduced. Concentration of current at a specific part of the hollow tube adversely affects the service life, but such a problem is reduced in the hollow tube made of platinum or platinum alloy of the present invention.
In addition, local heating of the hollow tube is reduced by reducing the concentration of current to a specific part. This prevents the hollow tube from being damaged by thermal stress during use.
Since the glass manufacturing apparatus of the present invention uses the platinum or platinum alloy hollow tube of the present invention as a molten glass conduit, local heating of the conduit that occurs during energization heating is reduced. For this reason, there is no possibility that the molten glass which distribute | circulates a conduit | pipe changes in quality. Moreover, there is no possibility that drift occurs in the molten glass flowing through the conduit.

  The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of a hollow tube made of platinum or a platinum alloy according to the present invention. The hollow tube 1 shown in FIG. 1 includes a main tube 11 and a branch tube 12 joined to the main tube 11. The main pipe 11 and the branch pipe 12 are platinum pipes or platinum alloy cylindrical pipes. The branch pipe 12 is joined so as to be orthogonal to the main pipe 11, and the hollow pipe 1 as a whole forms a T-shaped pipe. The hollow tube 1 made of platinum or platinum alloy according to the present invention is used for applications in which the branch tube 12 is heated by energization.

The hollow tube 1 made of platinum or platinum alloy according to the present invention is provided with a thick portion 15 except for the corner portion 14 and the vicinity thereof at the joint portion 13 of the main tube 11 and the branch tube 12 and the vicinity thereof. It is characterized by. That is, the hollow tube 1 made of platinum or platinum alloy according to the present invention is characterized in that a thick portion 15 is provided at the joint portion 13 of the main tube 11 and the branch tube 12 and in the vicinity thereof. However, as is apparent from FIG. 1, even in the joint portion 13 and the vicinity thereof, the thick portion is not provided in the corner portion 14 and the vicinity thereof.
Although not shown, thick portions are also provided at the same positions in the portions corresponding to the back side of the drawing of the main pipe 11 and the branch pipe 12.

  In this specification, when it says that the thick part 15 is provided in the junction part 13 and its vicinity, in the main pipe 11 and the branch pipe 12, the peripheral part of the joint part 13 is provided at the same time as providing the thick part in the joint part 13. It also means that the thick portion 15 is provided. In the main pipe 11 of the hollow pipe 1 shown in FIG. 1, the thick wall portion 15 extends from the joint portion 13 with the branch pipe 12 in the left direction in the figure, and the portion opposite to the joint portion 13 (the joint portion 13). The thick portion 15 is also provided on the side facing the surface. In the branch pipe 12 of the hollow pipe 1, the thick part 15 extends from the joint part 13 with the main pipe 11 in the right direction in the figure.

  In this specification, when the thick portion is provided except for the corner portion 14 and the vicinity thereof, that is, when the thick portion is not provided in the corner portion 14 and the vicinity thereof, in the main pipe 11 and the branch pipe 12, This means that no thick wall portion is provided in the corner portion 14 and its peripheral portion. In the main tube 11 of the hollow tube 1 in FIG. 1, no thick portion is provided in a certain range around the corner portion 14. In the branch tube 12 of the hollow tube 1, the thick portion is not provided on the corner portion 14 and the upper surface and the lower surface extending in the right direction in the drawing from the corner portion 14.

In the conventional hollow tube 100 shown in FIG. 5, when energization is performed so that a current flows in the direction of the arrow for the purpose of energizing and heating the branch tube 102, the current is concentrated on the corner 104 located in the shortest path. In the hollow tube 1 of the present invention, the branch tube 12 is energized and heated by providing the thick portion 15 except the corner portion 14 and the vicinity thereof at the junction portion 13 and the vicinity thereof between the main tube 11 and the branch tube 12. The current concentration on the corner 14 that occurs at the time is reduced. The reason for this will be described below.
The electrical resistance of a metallic material such as platinum or a platinum alloy is inversely proportional to the unit cross-sectional area of the material. Therefore, the thick portion 15 has a smaller electrical resistance than the corner portion 14 where the thick portion is not provided and the vicinity thereof. Therefore, for the purpose of energizing and heating the branch pipe 12, when energizing so that current flows in the direction of the arrow in FIG. 2, that is, when energizing so that current flows from the main pipe 11 to the branch pipe 12, it is more specific. Specifically, when energization is performed so that a current flows from the upper end of the main pipe 11 to the branch pipe 12, the current is distributed to the thick portion 15 and the current concentration on the corner portion 14 is reduced.

Accordingly, the shape, range, thickness, etc. of the thick portion 15 are not particularly limited as long as current concentration on the corner portion 14 can be reduced by dispersing the current in the thick portion 15.
However, the thick portion 15 is preferably provided so as to satisfy the following formulas (1) to (3).
L ₁ = 1.2d to 2.0d (1)
L ₂ = 0.2d to 1.5d (2)
t = 1.2t _{0 to} 1.5t ₀ (3)
In the above formulas (1) to (2), L ₁ is the maximum length (mm) of the thick portion 15 in the main pipe 11, and L ₂ is the maximum length (mm) of the thick portion 15 in the branch pipe 12. , D is the outer diameter (mm) of the branch pipe 12. The above formula (3) shows the relationship between the thickness t (mm) of the thick portion 15 in the hollow tube 1 and the thickness t ₀ (mm) of the portion other than the thick portion 15. Therefore, the relationship between the thickness t (mm) of the thick portion 15 in the main pipe 11 and the thickness t ₀ (mm) of the portion other than the thick portion 15 is shown, and the thickness of the thick portion 15 in the branch pipe 12 is shown. The relationship between the thickness t (mm) and the thickness t ₀ (mm) of the portion other than the thick portion 15 is shown. With respect to L ₁ and L ₂ , the maximum length of the thick portion 15 is specified, as is apparent from FIG. 1, the length of the thick portion 15 in the main pipe 11 and the branch pipe 12 varies depending on the part. Because. In general, as shown in FIG. 1, L ₁ and L ₂ are the maximum lengths of the thick portion 15 in the longitudinal direction of the main pipe 11 and the branch pipe 12, respectively.
When the thick portion 15 is provided so as to satisfy the above formulas (1) to (3), the current concentration on the corner portion 14 that occurs when the branch pipe 12 is energized and heated can be sufficiently reduced. Since platinum or platinum alloy, which is a constituent material of the main pipe 11 and the branch pipe 12, is expensive, it is preferable from the viewpoint of cost to make the range of the thick portion 15 as narrow as possible and to reduce the thickness as much as possible.

In the main pipe 11 and the branch pipe 12, the corner 14 and the range in the vicinity thereof, that is, the range of the portion where the thick portion is not provided are not particularly limited as long as the current concentration on the corner 14 can be reduced.
However, it is preferable not to provide a thick portion in the portion described below even in the vicinity of the joint portion of the main pipe 11 and the branch pipe 12 and in the vicinity thereof.
As for the main pipe 11, when the main pipe 11 is viewed from the end surface direction, it is preferable not to provide a thick portion in a predetermined angle range with the axis of the branch pipe 12 as the center. FIG. 3 is a view of the main pipe 11 of FIG. 1 as viewed from the upper end direction, and shows the vicinity of the corner portion 14 of the main pipe 11, that is, the portion indicated by line aa ′. In FIG. 3, Y indicates the axial direction of the branch pipe 12, and X indicates the axial direction orthogonal to the axis of the branch pipe 12. In the main pipe 11, it is preferable not to provide a thick portion within the range of the angle α with Y as the center. The angle α is preferably 20 to 90 degrees, and more preferably 30 to 60 degrees.

  Similarly, regarding the branch pipe 12, it is preferable not to provide a thick portion in a predetermined angle range around the axis of the main pipe 11 when the branch pipe 12 is viewed from the end surface direction. FIG. 4 is a view of the branch pipe 12 of FIG. 1 as viewed from the end face direction. However, the main pipe 11 is omitted. In FIG. 4, Y ′ indicates the axial direction of the main pipe 11, and X ′ indicates the axial direction orthogonal to the axis of the main pipe 11. In the main pipe 11, it is preferable not to provide a thick part within the range of the angle β centered on Y ′. The angle β is preferably 30 to 120 degrees, and more preferably 50 to 90 degrees.

  In the main pipe 11 and the branch pipe 12, by setting the range of the portion where the thick part is not provided as the above range, current concentration on the corner portion 14 that occurs when the branch pipe 12 is energized and heated can be sufficiently reduced. .

  As a means for providing the thick part 15 in the main pipe 11 and the branch pipe 12, the thick part 15 may be provided by bonding a thin plate made of platinum or a platinum alloy to the main pipe 11 and the branch pipe 12. The main pipe 11 and the branch pipe 12 may be molded so as to have the thick wall portion 15.

In FIG. 1, cylindrical pipes are shown as the main pipe 11 and the branch pipe 12, but the shapes of the main pipe 11 and the branch pipe 12 are not limited thereto. For example, the cross-sectional shape may be an elliptical shape, or a polygonal shape such as a quadrangle, hexagon, or octagon. In FIG. 1, straight pipes are shown as the main pipe 11 and the branch pipe 12, but the present invention is not limited to this. For example, a curved pipe may be used.
In FIG. 1, the branch pipe 12 is joined in the vicinity of the central portion in the longitudinal direction of the main pipe 11, but the position where the branch pipe 12 and the main pipe 11 are joined is not limited to this. The branch pipe 12 may be joined to a position closer to the end of the main pipe 11, for example, a position on the upper side or the lower side in the drawing. For example, the branch pipe 12 may be joined to the vicinity of the upper end or the lower end of the main pipe 11 so that the overall shape is substantially L-shaped. However, if the branch pipe 12 is joined at a position very close to the end of the main pipe 11, it is not possible to provide the thick portion 15 enough to reduce current concentration on the corner portion 14. It is preferable that the position where the corner portion 14 is separated from the end portion of the main pipe by 0.05 d or more. Here, d is the outer diameter (mm) of the branch pipe 12.

In FIG. 1, the branch pipe 12 is joined so as to be orthogonal to the main pipe 11, but the orientation direction of the branch pipe 12 with respect to the main pipe 11 is not limited to this. For example, the branch pipe 12 may be joined to the main pipe 11 so as to be oriented in an oblique direction. In this case, the inclination angle of the branch pipe 12 with respect to the main pipe 11 is preferably −45 to +45 degrees, and more preferably −30 to +30 degrees. Here, in FIG. 1, when the branch pipe 12 is orthogonal to the main pipe 11, the inclination angle of the branch pipe 12 with respect to the main pipe 11 is set to 0 degree. A case where the end portion of the branch pipe 12 faces upward in the drawing is a positive slope, and a case where the end portion of the branch pipe 12 faces downward in the drawing is a negative slope. However, the inclination angle of the branch pipe 12 with respect to the main pipe 11 is most preferably 0 degree. That is, as shown in FIG. 1, it is most preferable that the branch pipe 12 is joined so as to be orthogonal to the main pipe 11.
Further, in FIG. 1, one branch pipe 12 is joined to the main pipe 11, but the number of branch pipes joined to the main pipe is not limited to this. A plurality of branch pipes may be provided as long as a thick part can be provided at the junction of the main pipe and the branch pipe and in the vicinity thereof except for the corner and the vicinity thereof.

In the present invention, the dimensions of the hollow tube used as the straight tube and the branch tube are not particularly limited. For example, in the case of the hollow tube 1 shown in FIG. 1, the outer diameters D and d of the straight tube 11 and the branch tube 12 are preferably 50 to 800 mm, more preferably 100 to 600 mm. The lengths of the straight pipe 11 and the branch pipe 12 are preferably 200 to 3000 mm, and more preferably 400 to 1500 mm. In the straight pipe 11 and the branch pipe 12, the thickness t ₀ of the portion other than the thick portion 15 is preferably 0.4 to 5 mm, more preferably 0.6 to 1.5 mm.

In the present invention, the main pipe 11 and the branch pipe 12 are mainly composed of platinum. Therefore, the material is not limited to only platinum, but may be a platinum alloy. Specific examples of the platinum alloy include a platinum-gold alloy and a platinum-rhodium alloy. Further, reinforced platinum obtained by dispersing a metal oxide in platinum or a platinum alloy may be used. Examples of the metal oxide to be dispersed include Al ₂ O ₃ or a group 3A or 4A group metal oxide represented by ZrO ₂ or Y ₂ O ₃ .

  In the present invention, the straight pipe 11 and the branch pipe 12 can be joined by a known method, specifically, welding or diffusion bonding.

In the glass manufacturing apparatus of the present invention, the hollow tube of the present invention is used as a conduit for molten glass through which high-temperature molten glass passes. The hollow tube of the present invention can be widely used in a portion having a branch in a molten glass path of a glass production apparatus. Specific examples of the part using the hollow tube of the present invention include, for example, an outflow tube provided for removing impurities from a glass manufacturing apparatus, and a case where optical parts such as a lens and a prism are molded from the glass manufacturing apparatus. Examples include an outflow pipe for allowing molten glass to flow out into a mold for molding, a conduit from a melting tank to a molding tank, and the like.
In addition, the hollow tube of the present invention is a joint between a vacuum defoaming tank and a rising pipe, or a joint between a vacuum defoaming tank and a downcomer in a vacuum degassing apparatus that degass from molten glass in a vacuum atmosphere. Can be used for parts. In the vacuum degassing apparatus, even if a slight crack occurs in the hollow tube, it becomes a big problem. Therefore, the current concentration of the hollow tube of the present invention in the specific part when the branch tube is energized and heated is reduced. It is a preferred site to use.
In the glass manufacturing apparatus of the present invention, local heating of the conduit that occurs during energization heating is reduced. For this reason, there is no possibility that the molten glass which distribute | circulates a conduit | pipe changes in quality. Moreover, there is no possibility that drift occurs in the molten glass flowing through the conduit.

Hereinafter, the present invention will be further described by examples.
Example 1
In this example, a T-shaped hollow tube 1 shown in FIG. 1 was produced. In the hollow tube 1, the main tube 11 and the branch tube 12 are joined by welding. The dimensions and constituent materials of the main pipe 11 and the branch pipe 12 are as follows.
Main 11
Outer diameter D: 405mm
Length: 650mm
Wall thickness t ₀ : 1.0 mm
Maximum length L ₁ of the thick portion 15: 500 mm
Thickness t of thick part 15: 1.3 mm
Constituent material: Platinum-rhodium alloy (platinum 90 mass%, rhodium 10 mass%)
Branch pipe 12
Outer diameter d: 300mm
Length: 1000mm
Wall thickness t ₀ : 1.0 mm
Maximum length L ₂ of the thick part 15: 300 mm
Thickness t of thick part 15: 1.3 mm
Constituent material: Platinum-rhodium alloy (platinum 90 mass%, rhodium 10 mass%)
3 is 45 degrees, and the angle β in FIG. 4 is 60 degrees.

In the hollow tube 1 shown in FIG. 1, a platinum alloy (platinum-rhodium alloy) electrode (not shown) having a donut shape is joined to the upper end of the main tube 11 and the end of the branch tube 12 by welding. . The electrode was connected to an external power source (alternating current), and energized so that current flowed in the direction of the arrow in FIG. The energization conditions are as follows.
Voltage: 10V
Current: 5000A
Energization time: 10 days During energization, the temperature distribution near the junction 13 was observed using a thermocouple. As a result, no remarkable local heating was observed near the corner 14. This result shows that the current is distributed to the thick portion 15 and the current concentration on the corner portion 14 is reduced.

(Comparative Example 1)
A conventional hollow tube 100 having no thick part shown in FIG. 5 was produced. In the hollow tube 100, the main tube 101 and the branch tube 102 are joined by welding. The dimensions and constituent materials of the main pipe 101 and the branch pipe 102 are as follows.
Main 101
Outer diameter: 405mm
Length: 650mm
Thickness: 1.0mm
Constituent material: Platinum-rhodium alloy (platinum 90 mass%, rhodium 10 mass%)
Branch pipe 102
Outer diameter: 300mm
Length: 1000mm
Thickness: 1.0mm
Constituent material: Platinum-rhodium alloy (platinum 90 mass%, rhodium 10 mass%)
As in Example 1, a platinum alloy electrode (not shown) was joined to the upper end of the main pipe 101 and the end of the branch pipe 102, and the current was heated so that current flowed in the direction of the arrow. Remarkable local heating was observed near the portion 104. This result indicates that current concentration at the corner 104 occurred. After energization, the occurrence of cracks was confirmed at the site where local heating was observed.

FIG. 1 is a perspective view showing an embodiment of a hollow tube made of platinum or a platinum alloy according to the present invention. FIG. 2 is a view similar to FIG. 1 and shows the flow of current when the branch pipe 12 is heated by energization. FIG. 3 is a view of the main pipe 11 shown in FIG. 1 as viewed from the upper end direction, and shows a portion indicated by a line aa ′ in FIG. 1. FIG. 4 is a view of the branch pipe 12 shown in FIG. 1 as viewed from the end face direction. However, the main pipe 11 is omitted. FIG. 5 is a perspective view showing a conventional hollow tube having a branch tube.

Explanation of symbols

1: Hollow tube 11: Main tube 12: Branch tube 13: Joint portion 14: Corner portion 15: Thick portion 100: Hollow tube 101: Main tube 102: Branch tube 103: Joint portion 104: Corner portion

Claims (5)

A main pipe and a branch pipe joined to the main pipe, platinum or a platinum hollow pipe used for applications in which the branch pipe is energized and heated;
A hollow tube made of platinum or a platinum alloy, characterized in that a thick portion is provided at and near the junction between the main pipe and the branch pipe except for the corner and the vicinity thereof. The said thick part satisfy | fills following formula (1) thru | or (3), The hollow tube made from platinum or a platinum alloy of Claim 1 characterized by the above-mentioned.
L ₁ = 1.2d to 2.0d (1)
L ₂ = 0.2d to 1.5d (2)
t = 1.2t _{0 to} 1.5t ₀ (3)
L ₁ : Maximum length of the thick part in the main pipe (mm)
L ₂ : Maximum length of the thick part in the branch pipe (mm)
d: Outer diameter of branch pipe (mm)
t: Thickness of thick part (mm)
t ₀ : Thickness (mm) of the hollow tube other than the thick part   The hollow tube made of platinum or a platinum alloy according to claim 1 or 2, wherein the branch tube is joined so as to be orthogonal to the main tube.   A glass manufacturing apparatus using the platinum or platinum alloy hollow tube according to any one of claims 1 to 3. A method of energizing and heating a hollow tube made of platinum or a platinum alloy according to any one of claims 1 to 3,
A method for energizing and heating a hollow tube made of platinum or a platinum alloy, wherein energization is performed so that a current flows from the main pipe to the branch pipe.

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