JP6500679B2 - Molten glass heating apparatus, glass manufacturing apparatus, and method of manufacturing glass article - Google Patents

Description

  The present invention relates to a molten glass heating apparatus, a glass manufacturing apparatus, and a method of manufacturing a glass article.

  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 as a conduit through which high-temperature molten glass passes. In the glass manufacturing apparatus, the conduit through which the molten glass passes is heated to ensure the fluidity of the molten glass. The conduit may be heated from the outside by a heat source such as a heater, but when the conduit is a hollow tube made of platinum or platinum alloy, the hollow tube is provided with an electrode for current application. It is widely practiced to heat the hollow tube.

  In the heating of the conduit, when the main pipe and the branch pipe were provided, there was a possibility that underheating of the branch pipe might occur.

  As a countermeasure against insufficient heating to a branch pipe, Patent Document 1 discloses a method of energizing and heating a composite pipe structure made of platinum that can be used as a conduit for molten glass. As shown in FIG. 7, the composite pipe structure 100 heated by this heating method includes two main pipes 101 and 102 and a branch pipe 103 connecting the main pipes 101 and 102.

  In this example, the path for energizing the branch pipe 103 is divided into a first energization path (current supply path) 120 and a second energization path 121. The first electric conduction path 120 connects the first main pipe 101 and the branch pipe 103. The second conduction path 121 connects the branch pipe 103 and the second main pipe 102. And energization control in the 1st energization path 120 and the 2nd energization path 121 is carried out independently, respectively.

WO 2006/123479

  However, in the heating method of Patent Document 1, the temperature difference in the inside of the main pipe and at the connection portion (branch portion) between the main pipe and the branch pipe has not been taken into consideration. Therefore, when the molten glass passes through the inside of the main pipe and the branch pipe, a temperature difference may occur in the molten glass, which may lead to inhomogenization of the molten glass.

  This invention is made in view of the said subject, and it heats a molten glass so that a temperature difference may not generate | occur | produce, and it aims at providing the molten glass heating apparatus which can suppress heterogeneity of a molten glass. Do.

In order to solve the above problems, according to one aspect of the present invention, there is provided a molten glass heating apparatus comprising: a composite pipe structure through which molten glass passes; and a conductive heating unit for conductively heating the composite pipe structure,
The composite pipe structure includes a main pipe extending substantially vertically with respect to a horizontal direction, an upper branch pipe branching from the main pipe at an upper side of the main pipe, and a lower portion branching from the main pipe at a lower side of the main pipe. Equipped with a branch pipe,
The electric heating unit includes a first electrode provided at the upper end of the main pipe, a second electrode provided at the lower end of the main pipe, and a third provided at the side end of the upper branch pipe. And forming a first current supply path for supplying a current between the first electrode and the second electrode, and between the first electrode and the third electrode. Forming a second current supply path for supplying current;
In the composite pipe structure,
0.4 <(sum of resistance of current flowing between the upper end of the main pipe and upper end of the branch portion and resistance of current flowing between the branch portion of the upper branch pipe and the lateral end / the main pipe Resistance of current flowing between the upper end and the lower end) <0.8
So as to satisfy the, relative to said main pipe, the upper branch pipe is arranged,
In the composite pipe structure,
0.55 <(a shortest path of current flowing from the upper end of the main pipe to the upper end of the branch through the main pipe, and from the upper end of the upper end of the branch through the uppermost portion of the inner peripheral portion of the upper branch pipe, A total of the path of the current flowing to the side end of the upper branch pipe in the generatrix direction of the cylindrical upper branch pipe / a current flowing from the upper end of the main pipe to the lower end of the branch from the upper end of the main pipe And from the lower end of the branch portion to the lateral end portion of the upper branch pipe in the generatrix direction of the cylindrical upper branch pipe from the lower end of the branch portion to the lower end of the inner branch portion of the upper branch pipe. Total of the current path) <0.77
The upper branch pipe is disposed with respect to the upper end of the main pipe so as to satisfy
A molten glass heating device is provided.

  According to one aspect of the present invention, in the molten glass heating apparatus, the molten glass can be heated such that a temperature difference does not occur, and the inhomogenization of the molten glass can be suppressed.

It is sectional drawing which shows the glass manufacturing apparatus by which the molten glass heating apparatus by the 1st Embodiment of this invention was mounted. It is a flowchart which shows the manufacturing method of the glass article of the manufacturing apparatus of FIG. 1 is a schematic view of a molten glass heating apparatus according to a first embodiment of the present invention. It is a see-through | perspective perspective view explaining the position of the upper branch pipe with respect to the main pipe in the composite pipe structure of the 1st Embodiment of this invention. Figure 2 is a schematic view of a system comprising a molten glass heating apparatus according to a second embodiment of the present invention; It is a table | surface which shows the temperature of the molten glass in the composite pipe structure which changed the position of the upper branch pipe with respect to the main pipe. It is a conceptual diagram of the energization heating device of a conventional example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and the description thereof will be omitted. In the present specification, “to” representing a numerical range means a range including the numerical values before and after that.

[Glass manufacturing equipment]
FIG. 1: is sectional drawing which shows the manufacturing apparatus of the glass plate (glass article) by which the molten glass heating apparatus by the 1st Embodiment of this invention was mounted. As shown in FIG. 1, the glass plate manufacturing apparatus has a melting apparatus 10, a molten glass conveying apparatus 20, a forming apparatus 30, a connecting apparatus 40, and a slow cooling apparatus 50.

  The melting apparatus 10 melts the glass raw material G1 to produce a molten glass G2. The melting apparatus 10 has, for example, a melting furnace 11 and a burner 12.

  The melting furnace 11 forms a melting chamber 11a that melts the glass material G1. The molten glass G2 is accommodated in the melting chamber 11a.

  The burner 12 forms a flame in the upper space of the melting chamber 11a. The radiant heat of the flame gradually melts the glass material G1 into the molten glass G2.

  The molten glass conveying device 20 conveys the molten glass G2 from the melting device 10 to the forming device 30, and supplies the molten glass G2 to the forming device 30. In the molten glass conveying device 20, a molten glass heating device 210 described later is provided.

  The forming device 30 forms the molten glass G2 supplied from the molten glass conveying device 20 into a ribbon-like glass ribbon G3. The forming apparatus 30 has, for example, a forming furnace 31 and a forming heater 32.

  The forming furnace 31 forms a forming chamber 31a for forming the molten glass G2. The temperature of the forming chamber 31 a decreases as going from the inlet of the forming furnace 31 to the outlet of the forming furnace 31. The forming furnace 31 has a float bath 311 and a ceiling 312 disposed above the float bath 311.

  The float bath 311 contains the molten metal M. For example, molten tin is used as the molten metal M. Besides molten tin, molten tin alloys can also be used. In order to suppress the oxidation of the molten metal M, the upper space of the forming chamber 31a is filled with a reducing gas. The reducing gas is composed of, for example, a mixed gas of hydrogen gas and nitrogen gas.

  The float bath 311 shapes the molten glass G2 continuously supplied on the molten metal M into a strip-like glass ribbon G3 using the liquid level of the molten metal M. The glass ribbon G3 is gradually solidified while flowing from the upstream side to the downstream side of the float bath 311, and pulled up from the molten metal M in the downstream area of the float bath 311.

  The forming heater 32 is suspended from the ceiling 312. A plurality of forming heaters 32 are provided at intervals in the flow direction of the glass ribbon G3, and adjust the temperature distribution in the flow direction of the glass ribbon G3. A plurality of forming heaters 32 are provided at intervals in the width direction of the glass ribbon G3 to adjust the temperature distribution in the width direction of the glass ribbon G3.

  The connecting device 40 connects the forming device 30 and the annealing device 50. A slight gap between the connecting device 40 and the annealing device 50 may be filled with thermal insulation. The connection device 40 includes a connection furnace 41, an intermediate heater 42, and a lift out roll 43.

  The connection furnace 41 is disposed between the forming furnace 31 and the annealing furnace 51 described later, and forms a connection chamber 41a that limits the heat removal of the glass ribbon G3 conveyed therebetween. Quenching of the glass ribbon G3 can be prevented between the forming furnace 31 and the annealing furnace 51.

  The intermediate heater 42 is disposed in the connection chamber 41a. A plurality of intermediate heaters 42 are provided at intervals in the transport direction of the glass ribbon G3, and adjust the temperature distribution in the transport direction of the glass ribbon G3. The intermediate heater 42 may be divided in the width direction of the glass ribbon G3 and adjust the temperature distribution in the width direction of the glass ribbon G3.

  The lift out roll 43 is disposed in the connection chamber 41 a. The lift out roll 43 is rotationally driven by a motor or the like, pulls up the glass ribbon G3 from the molten metal M, and conveys it from the forming furnace 31 to the lehr 51. A plurality of lift out rolls 43 are provided at intervals in the transport direction of the glass ribbon G3.

  The annealing device 50 anneals the glass ribbon G3 formed by the forming device 30. The slow cooling device 50 has a slow cooling furnace 51, a slow cooling heater 52, and a slow cooling roll 53.

  The annealing furnace 51 forms the annealing room 51a which anneals the glass ribbon G3. The temperature of the annealing chamber 51a is lower as it goes from the inlet of the annealing furnace 51 to the outlet of the annealing furnace 51.

  The annealing heater 52 is disposed in the annealing chamber 51a. A plurality of slow cooling heaters 52 are provided at intervals in the transport direction of the glass ribbon G3, and adjust the temperature distribution in the transport direction of the glass ribbon G3. The slow cooling heater 52 may be divided in the width direction of the glass ribbon G3, and may adjust the temperature distribution in the width direction of the glass ribbon G3.

  The annealing roller 53 is disposed in the annealing chamber 51a. The slow cooling roll 53 is rotationally driven by a motor or the like, and conveys the glass ribbon G3 from the inlet of the slow cooling furnace 51 toward the exit of the slow cooling furnace 51. A plurality of annealing rollers 53 are provided at intervals in the transport direction of the glass ribbon G3.

  The glass ribbon G3 annealed in the annealing device 50 is cut into a predetermined size by a cutter to obtain a glass plate as a product.

  In addition, the manufacturing apparatus of a glass plate may be various. For example, the glass plate manufacturing apparatus may have a fining device for degassing bubbles contained in the molten glass G2 in the molten glass transfer device 20.

[Method of producing glass article]
Next, with reference to FIG. 2, the manufacturing method of a glass plate using the manufacturing apparatus of the glass plate of the said structure is demonstrated. FIG. 2 is a flow chart showing a method of manufacturing a glass article according to the first embodiment. As shown in FIG. 2, the manufacturing method of a glass plate has melt | dissolution process S10, molten-glass conveyance process S20, shaping | molding process S30, and slow cooling process S50.

  In the melting step S10, a molten glass G2 is produced by melting the glass raw material G1.

  In the molten glass conveying step S20, the molten glass G2 is conveyed from the melting device 10 to the forming device 30.

  In the forming step S30, the molten glass G2 produced in the melting step S10 is formed into a band-shaped glass ribbon G3. For example, in the forming step S30, the molten glass G2 is continuously supplied onto the molten metal M, and the molten glass G2 is formed into a strip-like glass ribbon G3 using the liquid surface of the molten metal M. The glass ribbon G3 is gradually solidified while flowing from the upstream side to the downstream side of the float bath 311.

  In the annealing step S50, the glass ribbon G3 formed in the forming step S30 is annealed.

  The gradually cooled glass ribbon G3 is cut into a predetermined size by a cutting machine to obtain a glass plate as a product.

  In addition, the manufacturing method of a glass plate may be variously various. For example, the manufacturing method of a glass plate may have a clarification process of degassing the foam contained in molten glass G2 in molten glass conveyance process S20.

Molten glass heating device
First Embodiment
Next, the molten glass heating apparatus 210 of the present invention will be described with reference to FIG. FIG. 3 is a schematic view illustrating the molten glass heating apparatus 210 according to the first embodiment of the present invention.

  The molten glass heating device 210 is provided with a composite tube structure 220 and a conductive heating unit 230. Composite tube structure 220 includes a conduit that forms a flow path through which molten glass G2 passes. The electric heating unit 230 electrically heats the composite pipe structure 220.

  A composite pipe structure 220 shown in FIG. 3 includes a main pipe (also referred to as a main pipe) 1, an upper branch pipe 2, and a lower branch pipe 3 as conduits.

  The main pipe 1 extends substantially perpendicularly to the horizontal direction, and the upper branch pipe 2 branches from the main pipe 1 on the upper side of the main pipe 1, and the inside thereof communicates with the main pipe 1. Here, substantially perpendicular to the horizontal direction is within ± 10 degrees with respect to the vertical direction. The lower branch pipe 3 is branched from the main pipe 1 on the lower side of the main pipe 1, and the inside thereof communicates with the main pipe 1.

  In the configuration of FIG. 3, the lower branch pipe 3 is an introduction pipe for introducing the molten glass G2 into the main pipe 1, and the upper branch pipe 2 is a discharge pipe for discharging the molten glass G2 from the main pipe 1. As such, the configuration may be reversed.

The main pipe 1, the upper branch pipe 2 and the lower branch pipe 3 are hollow tubes made of platinum or platinum alloy. Specific examples of platinum alloys include platinum-gold alloys and platinum-rhodium alloys. Further, when said to be made of platinum or platinum alloy, it also includes made of reinforced platinum obtained by dispersing metal oxide in platinum or platinum alloy. In this case, examples of the metal oxide to be dispersed include Al ₂ O ₃ , or Group III, Group IV or Group 13 metal oxides in the periodic table represented by ZrO ₂ or Y ₂ O ₃ .

  In order to introduce an electric current to the wall of such a platinum-containing hollow tube, electrodes 4, 5, 6 and 7 to be described later are the upper end 1a of the main tube 1, the lower end 1b of the main tube 1, and the side ends of the upper branch tube 2. It is provided at the side end 3 a of the portion 2 a and the lower branch pipe 3.

  A lid member may be provided on the outer side (upper side) of the electrode 4 provided on the upper end 1 a of the main pipe 1 to prevent heat radiation from the molten glass G2.

  The electrode 4 is the upper end 1 a of the main pipe 1, the electrode 5 is the lower end 1 b of the main pipe 1, and the electrode 6 is the side end 2 a of the upper branch pipe 2. And the electrode 7 is joined to the outer periphery of the side end 3 a of the lower branch pipe 3.

  The electrodes 4, 5, 6, 7 are connected to ring-shaped electrodes 4a, 5a, 6a, 7a made of platinum or platinum alloy and one end of outer edges of the ring-shaped electrodes 4a, 5a, 6a, 7a. It comprises the electrodes 4b, 5b, 6b and 7b. The lead-out electrodes 4b, 5b, 6b, 7b are connected to power sources 24A, 24B, 24C described later, and when energized, current flows from the lead-out electrodes 4b, 5b, 6b, 7b to the ring-shaped electrodes 4a, 5a, 6a, 7a. It flows to the conduits 1, 2, 3 via

  The outer edge of the ring-shaped electrodes 4a, 5a, 6a, 7a may be provided with a portion made of metal material other than platinum or platinum alloy. Examples of such metal materials include rhodium, iridium, molybdenum, tungsten, nickel, palladium, copper, and alloys thereof.

  It is preferable to use platinum as a main constituent material also for the extraction electrodes 4b, 5b, 6b and 7b. However, the present invention is not limited to this, and may be made of a metal material other than platinum or platinum alloy described above.

  Then, an electrode (first electrode) 4 at the upper end 1 a of the main pipe 1 and an electrode (second electrode) 5 at the lower end 1 b are connected to form a first current supply path 21 for supplying a current. An electrode 4 at the upper end 1a of the main pipe 1 and an electrode 6 (third electrode) at the side end 2a of the upper branch pipe 2 are connected to form a second current supply path 22 for supplying a current. A third current supply path 23 for supplying current is formed by connecting the electrode 5 at the lower end 1b of the main pipe 1 and the electrode (fourth electrode) 7 at the side end 3a of the lower branch pipe 3 .

  The first current supply path 21 supplies current to the electrodes 5 and 4, the second current supply path 22 to the electrodes 4 and 6, and the third current supply path 23 to the electrodes 7 and 5, respectively. The composite tube structure 220 is energized and heated.

  In the electric heating unit 230, the first current supply path 21 is provided (inserted) with the first power supply 24A, and the second current supply path 22 is provided with the second power supply 24B. The third power supply 24C is provided in the current supply path 23 of the second embodiment. That is, the first power supply 24A is electrically connected to the electrodes 5 and 4, the second power supply 24B is electrically connected to the electrodes 4 and 6, and the third power supply 24C is electrically connected to the electrodes 7 and 5. It is connected.

  Furthermore, the current balance unit adjusts the current (current density) between the electrodes of the first current supply path 21, the second current supply path 22, and the third current supply path 23. It is equipped with 25.

  As one example, the three-phase alternating current power supply 24A, the power supply 24B and the power supply 24C respectively supply a single phase alternating current ia, a single phase alternating current ib and a single phase alternating current ic.

  Here, the current balance means 25 adjusts the current levels of the single-phase alternating current ia, the single-phase alternating current ib and the single-phase alternating current ic generated by the power supply 24A, the power supply 24B and the power supply 24C. It has a current balance function to balance. As adjustment of the current level, the phase of the current may be adjusted.

  The current balance means 25 includes, for example, a transformer including a plurality of coils whose winding ratio can be adjusted such that a single-phase alternating current is supplied between R and S, R and T, and S and T in a three-phase alternating current phase. It is configured to include an Automatic Current Regulator (ACR) and the like.

  Although FIG. 3 illustrates an example in which the current balance means 25 is described separately from the power supplies 24A, 24B and 24C, the current balance means 25 may be combined with the power supplies 24A, 24B and 24C to constitute a power supply system. .

  As an example, the current balance means 25 of this embodiment has a phase difference of 2π / 3 between the single phase AC current ia of the power supply 24A, the single phase AC current ib of the power supply 24B, and the single phase AC current ic of the power supply 24C. Adjust the current to 4π / 3. When the phase difference is set in this way, the sum of the potential differences of the three power supplies 24A, 24B, 24C is always constant.

  Therefore, the current ia flowing through the first current supply path 21 connecting the upper end 1a and the lower end 1b of the main pipe 1 and the second current connecting the upper end 1a of the main pipe 1 and the side end 2a of the upper branch pipe 2 The current ib flowing through the supply path 22 and the current ic flowing through the third current supply path 23 connecting the lower end 1b of the main pipe 1 and the side end 3a of the lower branch pipe 3 are controlled to be equal to each other.

  As described above, when uniform current is supplied to each current supply path, in FIG. 3, the upper end (upper end of connection, upper corner) Ja of the branch portion between the main pipe 1 and the upper branch pipe 2 is the first current supply. The currents supplied from the path 21 and the second current supply path 22 overlap and flow. Furthermore, the branch upper end Ja is located in the shortest path of the current flowing from the upper end 1 a of the main pipe 1 to the upper branch pipe 2. Accordingly, the upper end Ja of the branch portion is a portion where current concentrates.

  Therefore, local heating may occur due to current concentration at the branch upper end Ja.

  For this reason, when heating the upper branch pipe 2, it is preferable that local heating not be generated at the upper end Ja of the branch portion. Therefore, in the present embodiment, by defining the dimensions of the composite pipe structure 220, Reduce the concentration of current. Specifically, in the molten glass heating apparatus 210 of the present embodiment, in the composite pipe structure 220, branching is performed by appropriately setting the position of the upper branch pipe 2 with respect to the height (length) Hm of the main pipe 1 Energization control can be performed easily and appropriately so that local heating is not generated at the upper end Ja of the part.

  Here, specific occurrence of local heating will be discussed in terms of the dimensions of the composite tubular structure 220.

  When the composite tube structure 220 surrounding the molten glass G2 is electrically heated, P is heat quantity (W), I is current (A), R is resistance (Ω),

で熱量が発生する。ここで、Ｈを発熱量（Ｊ）、Ｔを時間（ｓｅｃ）とすると、

Heat is generated. Here, when H is a calorific value (J) and T is a time (sec),

の発熱量が発生する。
この際、流れる電流は、Ｖを電圧（Ｖ）として

Generates a calorific value of
At this time, the flowing current is such that V is a voltage (V).

である。ここで、抵抗は、Ｓを導体（導管）の断面積（ｍ^２）、ｌを導体の長さ（ｍ）、ρを材料の比抵抗（電気抵抗率）（Ω・ｍ）として、

It is. Here, resistance is the cross-sectional area (m ² ) of the conductor (conduit), l is the length of the conductor (m), 比 is the specific resistance of the material (electrical resistivity) (Ω · m),

で表される。導管の内径（内側直径）をＤ、導管の厚みをｔとし、式（４）に当てはめると、

Is represented by Assuming that the inner diameter (inner diameter) of the conduit is D, the thickness of the conduit is t, and equation (4) is applied,

ここで、主管１及び上部分岐管２の厚みｔは、０．１ｍｍ〜３ｍｍ程度で、導管の内径Ｄに対して顕著に小さいため（Ｄ＞＞ｔ）、式（５）は、下記のように近似できる。

Here, since the thickness t of the main pipe 1 and the upper branch pipe 2 is about 0.1 mm to 3 mm and is significantly smaller than the inner diameter D of the conduit (D >> t), the formula (5) is as follows It can be approximated to

πは円周率であり、ρは材料の比抵抗であり、ｔは厚みであるため、式（６）の「２ρ／πｔ」は、すべての導管１、２、３で一定である。よって、本実施形態の複合管構造体２２０において、電流が流れる部位の「ｌ／Ｄ」の比率を比較することで、導管における抵抗値Ｒ、及び流れる電流値を比較することができるため、電流量で局所的な熱の発生を予測しうる。

is the specific resistance of the material and t is the thickness, the "2ρ / πt" in equation (6) is constant for all conduits 1, 2, 3. Therefore, in the composite tube structure 220 of the present embodiment, the resistance value R in the conduit and the current value flowing can be compared by comparing the ratio of “l / D” of the portion where the current flows, so the current The amount can predict local heat generation.

  In the present embodiment, the dimensions of each conduit and the dimensions of the connection position (branch position) in the composite pipe structure 220 are set as follows in order to prevent the generation of heat locally at the upper end Ja of the branch portion. In addition, these dimensions were specified in consideration of the temperature calculation result of the Example mentioned later.

  The dimensions of the ring-shaped electrodes 4, 5, 6, 7 provided at the upper end 1a, the lower end 1b, and the side ends 2a, 3a of the branch pipes 2, 3 are cylindrical It is negligibly small compared to the dimensions of the body of the. Thus, the resistance of the electrodes 4, 5, 6, 7 is negligibly small compared to the resistance of the cylindrical body of the conduits 1, 2, 3.

  FIG. 4 is a transparent perspective view for explaining the position of the upper branch pipe 2 with respect to the main pipe 1. In FIG. 4, α represents the entire main pipe 1, β represents the upper branch pipe 2, and γ represents a branch upper portion (portion above the upper end of the branch portion Ja) in the main pipe 1.

  In the present embodiment, in order to properly install the position of the upper branch pipe 2 with respect to the main pipe 1, the following description is given focusing on the position (distance h) from the upper end 1 a of the main pipe 1 to the upper end Ja Then, it is suitable.

  In the present embodiment, “0.4 <(resistance of current flowing between upper end 1a of main pipe 1 and upper end Ja of branch part (γ)) and between branch part J of upper branch pipe 2 and side end 2a It is preferable that the sum of the resistances of the current flowing through (β) / the resistance of the current flowing through (α) between the upper end 1a and the lower end 1b of the main pipe 1 satisfy <0.8 ”.

  Here, the above-mentioned “[the resistance of the current flowing between the upper end 1a of the main pipe 1 and the upper end Ja of the branch part (γ)] and [the branch part J of the upper branch pipe 2 and the side end 2a (β The ratio of the sum of [the resistance of the current flowing through)] to [the resistance of the current flowing between (a) between the upper end 1a and the lower end 1b of the main pipe 1] is defined as a ratio A.

  Here, the branch portion J of the upper branch pipe 2 is a connection portion between the main pipe 1 and the upper branch pipe 2. For example, when the main pipe 1 extends in the vertical direction and the upper branch pipe 2 branches vertically from the main pipe 1, the branch portion J, which is a connection portion, has a substantially circular shape.

  The ratio A is more preferably greater than 0.45, still more preferably greater than 0.5. Also, the ratio A is more preferably less than 0.75, still more preferably less than 0.7.

  As a specific example, the main pipe 1 extends in the vertical direction, the upper branch pipe 2 branches vertically to the main pipe 1, extends in the horizontal direction, and the electrode 6 of the side end 2 a forms the upper branch pipe 2. When installed vertically, the ratio A is expressed by the following equation.

  The height (length) of the main pipe 1 is Hm, the inner diameter of the main pipe 1 is D1, the length of the upper branch pipe 2 (ie, the length of the generatrix of the peripheral surface of the cylindrical upper branch pipe 2) L, the upper branch Assuming that the inner diameter of the pipe 2 is D2, and the distance from the upper end 1a of the main pipe 1 to the upper end of the upper branch pipe 2 is h, the position where the upper branch pipe 2 is provided with respect to the main pipe 1 is

と設定することができる。
この場合も、
０．４ ＜比率Ａ＝（（ｈ／Ｄ１）＋（Ｌ／Ｄ２））／（Ｈｍ／Ｄ１）＜０．８
を満たしていると好ましい。

And can be set.
Again,
0.4 <ratio A = ((h / D1) + (L / D2)) / (Hm / D1) <0.8
Preferably.

  Here, the upper branch pipe 2 may be inclined without extending in the horizontal direction. When the upper branch pipe 2 does not extend in the horizontal direction but is inclined and the electrode 6 of the side end 2a is installed in the vertical direction, the correction from the equation (7) is unnecessary.

  In addition, the ratio A is not limited to Formula (7). For example, when the upper branch pipe 2 does not extend in the horizontal direction and is inclined and the electrode 6 at the side end 2a is not installed in the vertical direction, the cross-sectional area S of the upper branch pipe 2 (β) and With respect to the length L, addition or subtraction correction is required from the equation (7) based on the division by the relationship between the angle of the branch and the angle of the end.

  Whether the upper branch pipe 2 is horizontal or inclined, the above-mentioned ratio A is “[resistance of current flowing to the branch upper portion γ in the main pipe 1] and [the current flowing to the upper branch pipe 2 (β) It shows the ratio of [the resistance] and [the resistance of the current flowing through the entire main pipe 1 of the main pipe 1].

  By setting 0.4 <ratio A <0.8 in this manner, local heating generated at the upper end Ja of the branching portion is suppressed, and the molten glass G2 is uniformly heated in the composite tube structure 220, which causes inhomogeneity. Can be suppressed.

Moreover, in the present invention, it is preferable that the position where the upper branch pipe 2 is provided with respect to the upper end 1 a of the main pipe 1 satisfy the following expression. Here, the lower end Jb of the branched portion is the lower end (lower corner) of the connection portion between the main pipe 1 and the upper branched pipe 2 in FIG. 3.
“0.55 <(from the upper end 1a of the main pipe 1 through the main pipe 1 to the upper end Ja of the branch portion, the shortest path of the current flowing from the upper end Ja of the branched portion The sum SD with the path of the current flowing to the side end 2a of the upper branch pipe 2 in the generatrix direction of the cylindrical upper branch pipe 2 / From the upper end 1a of the main pipe 1 through the main pipe 1 from the upper end 1a of the main pipe 1 To the generatrix direction of the cylindrical upper branch pipe 2 from the shortest path of the current flowing from the lower end of the branch portion Jb through the lower end of the inner peripheral portion of the upper branch pipe 2 to the lateral end 2a of the upper branch pipe 2 Total LD with the path of the current flowing to) <0.77 "
Here, the above-mentioned “[shortest path of current flowing from the upper end 1a of the main pipe 1 through the main pipe 1 to the upper end of the branch portion Ja and from the upper end of the branched portion Total SD of the path of the current flowing to the side end 2a of the upper branch pipe 2 in the generatrix direction of the cylindrical upper branch pipe 2] [from the upper end 1a of the main pipe 1 through the main pipe 1] The shortest path of the current flowing to the lower end of the branch portion Jb, and the lowermost portion of the inner peripheral portion of the upper branch pipe 2 from the lower end Jb of the branch portion, the side of the upper branch pipe 2 in the generatrix direction of the cylindrical upper branch pipe 2 A ratio B divided by the total LD of the current flowing to the end 2a and the path of the current is defined as a ratio B.

  Since the main pipe 1 is disposed substantially vertically to the horizontal direction, current flows from the upper end 1 a of the main pipe 1 through the main pipe 1 to the branched upper end Ja in a substantially vertical direction.

  Also, current flows from the upper end 1a of the main pipe 1 through the main pipe 1 to the side end (left end or right end) of the connection between the main pipe 1 and the upper branch pipe 2 (ie, the branch J of the upper branch pipe 2). After flowing in the substantially vertical direction, it flows from the side end of the branch portion J to the lower end Jb of the branch portion along the arc of the branch portion J.

  Further, as shown in FIG. 4, when the main pipe 1 extends in the vertical direction and the upper branch pipe 2 branches vertically from the main pipe 1, the generatrix direction of the upper branch pipe 2 which is in the shape of a horizontally oriented cylinder is , Horizontal.

  The ratio B is more preferably greater than 0.60. Also, the ratio B is more preferably less than 0.70.

  As a specific example, the main pipe 1 extends in the vertical direction, the upper branch pipe 2 branches vertically from the main pipe 1 and extends in the horizontal direction, and the electrode 6 of the side end portion 2a with respect to the upper branch pipe 2 When installed vertically, since the length of the generatrix of the straight cylindrical upper branch pipe 2 is equal to the length L of the upper branch pipe 2, the ratio B is

と設定することができる。
この場合も、
０．５５＜比率Ｂ＝（ｈ＋Ｌ）／（ｈ＋（５／４）Ｄ２＋Ｌ）＜０．７７
を満たしていると好ましい。

And can be set.
Again,
0.55 <ratio B = (h + L) / (h + (5/4) D2 + L) <0.77
Preferably.

  As shown in FIG. 4, the current passing through the route SD (h + L) passes through the upper end Ja of the branch portion of the main pipe 1 and the upper branch tube 2, and the current passing through the route LD (h + (5/4) D2 + L) It passes through the lower end Jb of the branch part.

  Here, the upper branch pipe 2 may be inclined without extending in the horizontal direction. The upper branch pipe 2 does not extend in the horizontal direction and is inclined, and the electrode 6 of the side end 2a is installed in the vertical direction, and the circular side end which becomes the bottom of the cylinder of the upper branch pipe 2 If it is an oblique cylindrical shape in which the generatrix of the part 2a and the circumferential surface obliquely intersect, the correction from the equation (8) is unnecessary.

  In addition, the ratio B is not limited to Formula (8). For example, in the case where the upper branch pipe 2 does not extend in the horizontal direction but is inclined and the electrode 6 at the side end 2a is not installed in the vertical direction, the length L of the upper branch pipe 2 (β) From the equation (8), it may be necessary to correct for addition or subtraction based on the case of the relationship between the angle of the branch and the angle of the end. For example, it is a case where it connects by making it cut by cutting the right cylindrical shape where the generatrix of a bottom face and a circumferential surface intersects perpendicularly.

  Thus, “from the upper end 1 a of the main pipe 1 through the main pipe 1 to the branch upper end Ja, the shortest path of the current flowing from the upper end 1 a of the main pipe 1 to the upper end of the inner peripheral portion of the upper branch pipe 2 , The sum SD of the path of the current flowing to the side end 2a of the upper branch pipe 2 in the generatrix direction of the cylindrical upper branch pipe 2] [branch from the upper end 1a of the main pipe 1 through the main pipe 1 The shortest path of the current flowing to the lower end Jb and the lower end of the inner peripheral portion of the upper branch pipe 2 from the lower end Jb of the branch portion, the side of the upper branch pipe 2 in the generatrix direction of the cylindrical upper branch pipe 2 The ratio B indicating the ratio of the total LD divided by the path of the current flowing to the end 2a] is the case where the upper branch pipe 2 is horizontal (in the case of a straight cylinder shape) or the case where it is inclined (right cylinder shape In the case of shape) includes both.

  As described above, by setting 0.55 <ratio B <0.77, generation of a temperature difference between the upper branch tube 2 and the upper side of the tube interior is suppressed, and the molten glass in the composite tube structure 220 The occurrence of the temperature difference of G2 can be suppressed.

  The relationship between changes in the dimensions A and B when the installation position of the upper branch pipe 2 is changed in the composite pipe structure 220 is as follows.

  When the distance h from the upper end 1a of the main pipe 1 to the upper end 1a of the branch portion of the upper branch pipe 2 becomes longer, both the ratio A and the ratio B become larger.

  When the height Hm of the main pipe 1 decreases, the ratio B remains unchanged, but the ratio A increases because the ratio of the branch upper portion β increases.

  As the length L of the upper branch pipe 2 becomes longer, both the ratio A and the ratio B become larger.

  When changing two or more dimensions, such as the distance h and the height Hm, the ratio A and the ratio B change in conjunction with each other according to the ratio of the change.

  When the length of the conduit is set by satisfying the above ratio, the height Hm of the main pipe 1 is preferably 500 mm to 3000 mm, and the length L of the upper branch pipe 2 is preferably 50 mm to 1500 mm. The height Hm is more preferably 800 mm or more, still more preferably 1100 mm or more. Further, the height Hm is more preferably 2700 mm or less, still more preferably 2400 mm or less. The length L is more preferably 150 mm or more, still more preferably 250 mm or more. Further, the length L is more preferably 1300 mm or less, further preferably 1100 mm or less. When the height Hm of the main pipe 1 is 3000 mm or less, the resistance of the current of the main pipe 1 is suppressed, and the molten glass G2 can be sufficiently heated. In addition, when the length L of the upper branch pipe 2 is 1500 mm or less, the resistance of the current of the upper branch pipe 2 is suppressed, and the molten glass G2 can be sufficiently heated.

  The inner diameter D1 of the main pipe 1 is preferably 50 mm to 500 mm. The inner diameter D1 is more preferably 100 mm or more, still more preferably 150 mm or more. The inner diameter D1 is more preferably 450 mm or less, and still more preferably 400 mm or less.

  The inner diameter D2 of the upper branch pipe 2 needs to be shorter than half the height Hm of the main pipe in order to install the upper branch pipe 2 on the upper portion (half to upper) of the main pipe 1. It is preferable that D2 be 50 mm to 500 mm. The inner diameter D2 is more preferably 100 mm or more, still more preferably 150 mm or more. Further, the inner diameter D2 is more preferably 450 mm or less, still more preferably 400 mm or less.

  The distance h from the upper end 1a of the main pipe 1 to the upper end of the branch portion Ja of the upper branch pipe 2 is half of the height Hm of the main pipe 1 in order to install the upper branch pipe 2 on the upper portion (half to upper) of the main pipe 1 The distance h needs to be shorter, and the distance h is preferably 50 mm to 500 mm. The distance h is more preferably 100 mm or more, still more preferably 150 mm or more. The distance h is more preferably 450 mm or less, and still more preferably 400 mm or less.

  If the distance h is too short, the upper branch pipe 2 will be close to the upper end 1a of the main pipe 1, so there is a possibility that air bubbles may be caught during conveyance of the molten glass G2, and if the distance h is too long, the branch upper end Since the temperature of Ja easily rises, the occurrence of a defect can be suppressed by setting the appropriate distance h.

  Moreover, in the glass manufacturing apparatus, the main pipe 1 of the composite pipe structure 220 may be provided with a stirrer for stirring the molten glass G2. When the main pipe 1 is provided with a stirrer, the homogenization of the state (temperature, homogeneity, etc.) of the molten glass G2 can be enhanced.

  Although the lower branch pipe 3 is provided on the side opposite to the upper branch pipe 2 with respect to the main pipe 1 when the above configuration is viewed from above, the upper branch pipe 2 and the lower branch pipe It does not need to be installed on the opposite side to 180 degrees from 3 and may be installed at a predetermined angle of 45 degrees or more.

  Further, although the case where the branch pipes 2 and 3 branch horizontally from the main pipe 1 has been described above, the branch pipes 2 and 3 may branch off from the main pipe 1 in a range not perpendicular. Also in this case, it is preferable to configure the composite tubular structure 220 so as to satisfy the ratio as described above.

Second Embodiment
In the present embodiment, a case will be described in which two of the above-described molten glass heating devices are arranged side by side in the molten glass conveying device 20 shown in FIG. 1.

  FIG. 5 shows a system 200 comprising a molten glass heating apparatus according to a second embodiment of the present invention.

  Similar to the configuration of FIG. 3, in the composite pipe structure 220 of the molten glass heating apparatus 210 described on the left side of FIG. 5, the lower branch pipe 3 is an inlet pipe on the inlet side for introducing the molten glass G2 into the main pipe 1 The upper branch pipe 2 is a discharge pipe for discharging the molten glass G2 from the main pipe 1.

  In the composite pipe structure 250 of the second molten glass heating device 240, the upper branch pipe 2R is an inlet pipe on the inlet side for introducing the molten glass G2 discharged from the upper branch pipe 2 into the main pipe 1R. 3R is a tube on the outlet side for discharging the molten glass G2 that has passed through the main tube 1R. The side end 2 c of the upper branch pipe 2 R is disposed to face the side end 2 a of the upper branch pipe 2 of the first molten glass heating device 210.

  In the present embodiment, since the current balance units 25 and 25R are separately provided in the current application heating unit 230 of the first molten glass heating device 210 and the current application heating unit 260 of the second molten glass heating device 240, Electrical heating is controlled independently.

  The molten glass heating apparatus (system) which concerns on embodiment of this invention is not restricted to the float method shown to FIG.1 and FIG.2, You may apply it to the fusion method and the manufacturing method of another glass article.

  Moreover, the glass article manufactured using the glass manufacturing apparatus by which the molten glass heating apparatus of this invention was mounted is not restricted to a glass plate, Various shapes may be sufficient.

  As mentioned above, although the embodiment etc. of a molten glass heating device were described, the present invention is not limited to the above-mentioned embodiment etc., within the scope of the gist of the present invention described in the claims, various modification, improvement It is possible.

  The dimensions of the above-described molten glass heating apparatus were changed, and the surface temperature of the composite tube structure was calculated by simulation (finite element method). The following Examples 1 to 7 are Examples, and Examples 8 to 10 are Comparative Examples.

<Examples 1 to 10>
In Example 1, the dimensions of each part in the molten glass heating apparatus were as follows.
Main pipe height Hm: 1000 mm
Main pipe inner diameter D1: 200 mm
Branch pipe length L: 450 mm
Branch tube inner diameter D2: 200 mm
Distance h between main pipe upper end and branch pipe upper end h: 220 mm
In Examples 2 to 10, the dimensions of each part in the molten glass heating apparatus of Example 1 were changed as shown in FIG.

  In the table of FIG. 6, T0 is the temperature of the central portion of the main pipe 1, T1 is the temperature of the upper portion (branch upper portion γ) of the main pipe 1, T2 is the upper end (corner portion) of the branched portion And T3 indicate the temperature of the lower end (corner) Jb of the branched portion between the main pipe 1 and the upper branch pipe 2.

  The central portion of the main pipe 1 for which the temperature T0 has been calculated means that it is a vertical position about half the height Hm of the main pipe 1.

  From FIG. 6, when the ratio A is 0.33 (example 8) 1.41 (example 9), the temperature difference <T1-T0>, <T2 between the central part of the main pipe 1 and the branch upper part γ and the branch upper end Ja. -T0> exceeds 20 ° C., respectively. When the ratio A is 0.80 (example 10), the temperature difference <T2-T0> and <T3-T0> between the central portion of the main pipe 1 and the upper end Ja of the branch and the lower end Jb of the branch are 20 ° C. Over.

  Therefore, the ratio A is preferably more than 0.4 and less than 0.8.

  Further, according to FIG. 6, when the ratio B is 0.44 (example 8) or 0.77 (example 9), the temperature difference between the central portion of the main pipe 1 and the upper branch portion γ and the upper end Ja of the branch portion T0> and <T2-T0> exceed 20 ° C., respectively. When the ratio B is 0.90 (Example 10), the temperature difference between the central portion of the main pipe 1 and the upper end of the branch portion Ja and the lower end of the branch portion Jb <T2-T0> and <T3-T0> is 20 ° C. Over.

  Therefore, the ratio B is preferably more than 0.55 and less than 0.77.

  Further, in setting the dimensions, it is more preferable that both of the above ranges be satisfied in the ranges of the ratio A and the ratio B described above.

  When both the ratio A and ratio B ranges are satisfied, as shown in Examples 1 to 7, the temperature difference between the central portion of the main pipe 1 and the branch upper portion γ, the branch upper end Ja, and the branch lower end Jb <T1 It is possible to reduce -T0>, <T2-T0>, and <T3-T0>, which is preferable.

  Since the molten glass heating apparatus of the present invention can electrically heat the entire main pipe and branch pipes included in the composite pipe structure to a desired temperature without excess or deficiency, electric heating of the flow path of the molten glass in the glass manufacturing apparatus Applicable

1,1R main (main)
1a upper end 1b lower end 2, 2R upper branch pipe 2a side end 3, 3R lower branch pipe 3a side end 4 (4a, 4b) first electrode 5 (5a, 5b) second electrode 6 (6a, 6a, 6b) Third electrode 7 (7a, 7b) Fourth electrode 10 Melting apparatus 20 molten glass conveying apparatus 21 first current supply path 22 second current supply path 23 third current supply path 24A first power source 24B Second power source 24C Third power source 30 Forming device 40 Connecting device 50 Annealing device 200 Molten glass heating system 210 Molten glass heating device (first molten glass heating device)
220 composite tube structure 230 electric heating unit 240 second molten glass heating device 250 composite tube structure 260 electric heating unit G2 molten glass Ja branch upper end Jb branch lower end J branch (connection)
From the upper end of the SD main pipe through the main pipe to the shortest path of the current flowing to the upper end of the branch, and from the upper end of the upper branch to the generatrix direction of the cylindrical upper branch pipe The total path of the current flowing to the side end of the upper branch pipe From the upper end of the LD main pipe, the shortest path of the current flowing to the lower end of the branch through the main pipe, and from the lower end of the branch to the inner circumference of the upper branch pipe Of the current flowing to the lateral end of the upper branch pipe in the generatrix direction of the cylindrical upper branch pipe through the lowermost portion

Claims (15)

A molten glass heating apparatus comprising: a composite pipe structure through which molten glass passes; and an electric heating unit for electrically heating the composite pipe structure,
The composite pipe structure includes a main pipe extending substantially vertically with respect to a horizontal direction, an upper branch pipe branching from the main pipe at an upper side of the main pipe, and a lower portion branching from the main pipe at a lower side of the main pipe. Equipped with a branch pipe,
The electric heating unit includes a first electrode provided at the upper end of the main pipe, a second electrode provided at the lower end of the main pipe, and a third provided at the side end of the upper branch pipe. And forming a first current supply path for supplying a current between the first electrode and the second electrode, and between the first electrode and the third electrode. Forming a second current supply path for supplying current;
In the composite pipe structure,
0.4 <(sum of resistance of current flowing between the upper end of the main pipe and upper end of the branch portion and resistance of current flowing between the branch portion of the upper branch pipe and the lateral end / the main pipe Resistance of current flowing between the upper end and the lower end) <0.8
To satisfy, the upper branch pipe to the main pipe is arranged,
In the composite pipe structure,
0.55 <(a shortest path of current flowing from the upper end of the main pipe to the upper end of the branch through the main pipe, and from the upper end of the upper end of the branch through the uppermost portion of the inner peripheral portion of the upper branch pipe, A total of the path of the current flowing to the side end of the upper branch pipe in the generatrix direction of the cylindrical upper branch pipe / a current flowing from the upper end of the main pipe to the lower end of the branch from the upper end of the main pipe And from the lower end of the branch portion to the lateral end portion of the upper branch pipe in the generatrix direction of the cylindrical upper branch pipe from the lower end of the branch portion to the lower end of the inner branch portion of the upper branch pipe. Total of the current path) <0.77
The upper branch pipe is disposed with respect to the upper end of the main pipe so as to satisfy
Molten glass heating device. In the composite pipe structure, when the upper branch pipe branches substantially vertically from the main pipe,
The height from the upper end to the lower end of the main pipe is Hm, the inner diameter is D1, the length of the upper branch is L, the inner diameter is D2, the upper end of the main pipe to the upper end of the branch of the upper branch If the distance is h, then
0.4 <((h / D1) + (L / D2)) / (Hm / D1) <0.8
The upper branch pipe is disposed with respect to the main pipe so as to satisfy
The molten glass heating apparatus according to claim 1. In the composite pipe structure, when the upper branch pipe branches substantially vertically from the main pipe,
Assuming that the length of the upper branch pipe is L, the inner diameter is D2, and the distance from the upper end of the main pipe to the upper end of the branch portion of the upper branch pipe is h.
0.55 <(h + L) / (h + (5/4) D2 + L) <0.77
The upper branch pipe is disposed with respect to the upper end of the main pipe so as to satisfy
A molten glass heating apparatus according to claim 1 or 2. The height Hm from the upper end to the lower end of the main pipe is 500 mm to 3000 mm,
The molten glass heating apparatus as described in any one of Claims 1-3 . The length L of the upper branch pipe is 50 mm to 1500 mm,
The molten glass heating apparatus as described in any one of Claims 1-4 . The inner diameter D1 of the main pipe is 50 mm to 500 mm,
The molten glass heating apparatus as described in any one of Claims 1-5 . The inner diameter D2 of the upper branch pipe is 50 mm to 500 mm and is shorter than half the height Hm of the main pipe,
The molten glass heating apparatus as described in any one of Claims 1-6 . The distance h from the upper end of the main pipe to the upper end of the branch portion of the upper branch pipe is 50 mm to 500 mm, and is shorter than half the height Hm of the main pipe,
Molten glass heating apparatus according to any one of claims 1-7. The conductive heating unit includes current balance means for adjusting current flowing in the first current supply path and the second current supply path.
The molten glass heating apparatus as described in any one of Claims 1-8 . A first power supply is provided in the first current supply path, a second power supply is provided in the second current supply path, and the current balance means includes the first power supply and the second power supply. Adjust the current phase of the
The molten glass heating apparatus of Claim 9 . A fourth electrode provided at a lateral end of the lower branch pipe,
Forming a third current supply path for supplying current between the second electrode and the fourth electrode provided at the lower end of the main pipe;
The current balance means adjusts current flowing in the first current supply path, the second current supply path, and the third current supply path.
The molten glass heating apparatus of Claim 9 or 10 . The composite tube structure is made of platinum or platinum alloy
Molten glass heating apparatus according to any one of claims 1 to 11. Glass manufacturing apparatus including a molten glass heating apparatus according to any one of claims 1 to 12. The glass manufacturing apparatus includes a first molten glass heating apparatus and a second molten glass heating apparatus which are configured of the molten glass heating apparatus,
In the first molten glass heating apparatus, the lower branch pipe is an inlet-side pipe for introducing the molten glass,
In the second molten glass heating apparatus, the lower branch pipe is a pipe on the outlet side for discharging the molten glass, and the side end of the upper branch pipe is the upper part of the first molten glass heating apparatus It is arranged to face the side end of the branch pipe,
The glass manufacturing apparatus of Claim 13 . A method of producing a glass article using the glass production apparatus according to claim 13 or 14 ,
A method for producing a glass article, comprising heating a glass material to obtain molten glass, and shaping and slowly cooling the molten glass to obtain a glass article.

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