TWI680109B - Molten glass heating device, glass manufacturing device, and glass article manufacturing method - Google Patents

Abstract

The present invention provides a molten glass heating device that heats a molten glass so as not to cause a temperature difference, thereby suppressing the heterogeneity of the molten glass.

The molten glass heating device 210 according to the present invention includes a composite pipe structure 220 including a main pipe 1 extending substantially perpendicularly to a horizontal direction, a branch pipe 2 above an upper side branch of the autonomous pipe 1, and a lower side of the autonomous pipe 1. A branch pipe 3 below the branch; and an electric heating section 230 including an electrode 4 provided at the upper end 1a of the main pipe 1, an electrode 5 provided at the lower end 1b of the main pipe 1, and a side end 2a of the upper branch pipe 2 The electrode 6 forms a first current supply path 21 for supplying a current between the electrode 4 and the electrode 5, and forms a second current supply path 22 for supplying a current between the electrode 4 and the electrode 6; and the composite tube structure 220 It satisfies "0.4 <(the resistance of the current flowing between the upper end 1a of the main pipe 1 and the upper end Ja of the branch (γ) and the flow between the branch J of the upper branch pipe 2 and the side end 2a (β) The total resistance of the current / resistance of the current flowing between the upper end 1a and the lower end 1b (α) of the main pipe 1) is configured as 0.8.

Description

Molten glass heating device, glass manufacturing device, and glass article manufacturing method

The present invention relates to a molten glass heating device, a glass manufacturing device, and a method for manufacturing glass articles.

In a glass manufacturing apparatus, a hollow tube made of platinum or a platinum alloy such as a platinum-gold alloy or a platinum-rhodium alloy is used as a conduit through which high-temperature molten glass passes. In the glass manufacturing apparatus, in order to ensure the fluidity of the molten glass, a pipe through which the molten glass passes is heated. Regarding the heating of the duct, although the duct may be heated from the outside by heat such as a heater, when the duct is a hollow tube made of platinum or a platinum alloy, the following operations are widely performed: An electrode for energization is provided, and the hollow tube is electrically heated.

When the main pipe and the branch pipe are provided during the heating of the duct, there is a possibility that insufficient heating in the branch pipe occurs.

As a countermeasure against insufficient heating in a branch pipe, Patent Document 1 discloses a method of electrically heating a composite pipe structure made of platinum that can be used as a conduit for molten glass. As shown in FIG. 6, 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, a 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 current path 120 connects the first main pipe 101 and the branch pipe 103. The second current path 121 connects the branch pipe 103 and the second main pipe 102. In addition, the communication between the first current path 120 and the second current path 121 is performed independently. Electric control.

[Prior technical literature] [Patent Literature]

[Patent Document 1] International Publication No. 2006/123479

However, the heating method of Patent Document 1 does not consider the temperature difference between the inside of the main pipe and the connection portion (branch) between the main pipe and the branch pipe. Therefore, when the molten glass passes through the inside of the main pipe and the branch pipe, there is a case where a temperature difference occurs in the molten glass, resulting in heterogeneity of the molten glass.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a molten glass heating device that can heat molten glass so as not to cause a temperature difference, thereby suppressing the heterogeneity of the molten glass.

In order to solve the above problems, according to one aspect of the present invention, a molten glass heating device is provided, which includes a composite pipe structure through which molten glass passes, and an electric current heating unit that electrically heats the composite pipe structure. The composite pipe structure includes: a main pipe, which extends substantially perpendicularly to the horizontal direction; an upper branch pipe, which is branched from the main pipe side above the main pipe; and a lower branch pipe, which is from the above side pipe under the main pipe. The main branch; the above-mentioned current heating and heating part includes a first electrode provided on the upper end of the main tube, a second electrode provided on the lower end of the main tube, and a third electrode provided on the side end of the upper branch tube to form a current A first current supply path is provided between the first electrode and the second electrode, and a second current supply path is provided to supply current between the first electrode and the third electrode. in, Satisfy 0.4 <(total of the resistance of the current flowing between the upper end of the main pipe and the upper end of the branch and the resistance of the current flowing between the branch of the upper branch pipe and the lateral end of the above The resistance of the current flowing between the upper end and the lower end of the main pipe) <0.8

In other words, the upper branch pipe is arranged on the main pipe.

According to one aspect of the present invention, in the molten glass heating device, the molten glass can be heated without causing a temperature difference, thereby suppressing the heterogeneity of the molten glass.

1‧‧‧Supervisor (main body manager)

1a‧‧‧upper

1b‧‧‧ bottom

1R‧‧‧Supervisor (main management)

2‧‧‧upper branch pipe

2a‧‧‧side end

2c‧‧‧side end

2R‧‧‧Upper branch pipe

3‧‧‧ lower branch pipe

3a‧‧‧side end

3R‧‧‧Lower branch pipe

4 (4a, 4b) ‧‧‧1st electrode

5 (5a, 5b) ‧‧‧ 2nd electrode

6 (6a, 6b) ‧‧‧3rd electrode

7 (7a, 7b) ‧‧‧ 4th electrode

10‧‧‧ Melting device

11‧‧‧ melting furnace

11a‧‧‧melting room

12‧‧‧ burner

20‧‧‧ Molten glass transfer device

21‧‧‧The first current supply path

22‧‧‧ 2nd current supply path

23‧‧‧3rd current supply path

24A‧‧‧1st power supply

24B‧‧‧Second Power Supply

24C‧‧‧3rd Power Supply

25‧‧‧Current balancing mechanism

25R‧‧‧Current balancing mechanism

30‧‧‧forming device

31‧‧‧forming furnace

31a‧‧‧forming room

32‧‧‧Forming heater

40‧‧‧ Connected device

41‧‧‧Connected Furnace

41a‧‧‧Connecting Room

42‧‧‧ Intermediate heater

43‧‧‧Lifting roller

50‧‧‧ Slow cooling device

51‧‧‧ Slow cooling furnace

51a‧‧‧ Slow Cooling Room

52‧‧‧ Slow cooling heater

53‧‧‧Chill Roll

100‧‧‧ composite pipe structure

101‧‧‧first supervisor

102‧‧‧ 2nd Supervisor

103‧‧‧ branch pipe

120‧‧‧The first power-on path

121‧‧‧ 2nd power-on path

200‧‧‧ Molten Glass Heating System

210‧‧‧ molten glass heating device (first molten glass heating device)

220‧‧‧ composite pipe structure

230‧‧‧ Electric heating section

240‧‧‧The second molten glass heating device

250‧‧‧ composite pipe structure

260‧‧‧ Electric heating section

311‧‧‧floating kiln

312‧‧‧Top

D1‧‧‧Inner diameter of Supervisor 1

D2‧‧‧Inner diameter of upper branch pipe 2

G1‧‧‧Glass Raw Materials

G2‧‧‧ molten glass

G3‧‧‧glass ribbon

Hm‧‧‧ height (length) of supervisor 1

h‧‧‧ The distance from the upper end 1a of the autonomous pipe 1 to the upper end Ja of the branch of the upper branch pipe 2

ia‧‧‧Single-phase AC current

ib‧‧‧ single-phase AC current

ic‧‧‧Single-phase AC current

J‧‧‧ branch (connection)

Ja‧‧‧ Branch top

Jb‧‧‧Bottom of the branch

L‧‧‧ Length of upper branch pipe 2

LD‧‧‧The shortest path of the current flowing from the upper end of the autonomous pipe to the lower end of the branch through the main pipe, and from the lower end of the branch to the inner peripheral portion of the upper branch pipe through the lower part of the upper branch pipe toward the upper branch pipe in the direction of the bus of the cylindrical upper branch pipe. Total of the path of the current flowing to the side end

M‧‧‧ Molten Metal

S10‧‧‧ Melting step

S20‧‧‧Molten glass transfer steps

S30‧‧‧Forming steps

S50‧‧‧Slow cooling step

SD‧‧‧ The shortest path of the current flowing from the upper end of the autonomous pipe to the upper end of the branch through the main pipe, and the uppermost branch pipe from the upper end of the branch through the inner peripheral part of the upper branch Total of the path of the current flowing to the side end

α‧‧‧Supervisor 1 Overall

β‧‧‧ Upper branch tube 2

γ‧‧‧Upper branch in supervisor 1

FIG. 1 is a cross-sectional view showing a glass manufacturing apparatus equipped with a molten glass heating apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a method for manufacturing a glass article in the manufacturing apparatus of FIG. 1. FIG.

Fig. 3 is a schematic view of a molten glass heating device according to the first embodiment of the present invention.

FIG. 4 is a perspective perspective view illustrating the position of the upper branch pipe relative to the main pipe in the composite pipe structure of the first embodiment of the present invention.

Fig. 5 is a schematic diagram of a system including a molten glass heating device according to a second embodiment of the present invention.

FIG. 6 is a conceptual diagram of the electric heating device of the previous example.

Hereinafter, the form for implementing this invention is demonstrated with reference to drawings. In each drawing, the same or corresponding components are marked with the same or corresponding symbols, and descriptions thereof are omitted. In this specification, "~" indicating a numerical range means a range including numerical values before and after.

[Glass manufacturing equipment]

FIG. 1 is a cross-sectional view showing a manufacturing apparatus for a glass plate (glass article) equipped with a molten glass heating apparatus according to a first embodiment of the present invention. As shown in Figure 1, the manufacture of glass plates The device includes a melting device 10, a molten glass transfer device 20, a forming device 30, a connection device 40, and a slow cooling device 50.

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

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

The burner 12 forms a flame in a space above the melting chamber 11a. By the radiant heat of the flame, the glass raw material G1 is gradually melted into the molten glass G2.

The molten glass transfer device 20 transfers the molten glass G2 from the melting device 10 to the molding device 30, and supplies the molten glass G2 to the molding device 30. The molten glass transfer device 20 is provided with a molten glass heating device 210 described below.

The molding device 30 shapes the molten glass G2 supplied from the molten glass transfer device 20 into a strip-shaped glass ribbon G3. The molding apparatus 30 includes, for example, a molding furnace 31 and a molding heater 32.

The molding furnace 31 forms a molding chamber 31a for molding the molten glass G2. The temperature from the inlet of the forming furnace 31 toward the outlet of the forming furnace 31 decreases, and the temperature of the forming chamber 31a decreases. The forming furnace 31 includes a floating throwing kiln 311 and a top portion 312 disposed above the floating throwing kiln 311.

The floating kiln 311 contains molten metal M. As the molten metal M, for example, molten tin is used. In addition to molten tin, molten tin alloys and the like can also be used. In order to suppress the oxidation of the molten metal M, the space above the forming chamber 31a is filled with a reducing gas. The reducing gas includes, for example, a mixed gas of hydrogen and nitrogen.

The floating kiln 311 uses the liquid surface of the molten metal M to form the molten glass G2 continuously supplied onto the molten metal M into a glass ribbon G3 having a plate shape. The glass ribbon G3 gradually solidifies while flowing from the upstream side to the downstream side of the floating throw kiln 311, and is lifted from the molten metal M in the downstream region of the floating throw kiln 311.

The forming heater 32 is suspended from the top 312. Forming heater 32 on glass ribbon G3 A plurality of them are provided at intervals in the moving direction, and the temperature distribution in the flow direction of the glass ribbon G3 is adjusted. In addition, a plurality of forming heaters 32 are provided at intervals in the width direction of the glass ribbon G3, and the temperature distribution in the width direction of the glass ribbon G3 is adjusted.

The connecting device 40 connects the forming device 30 and the slow cooling device 50. The narrow gap between the connection device 40 and the slow cooling device 50 can be filled with thermal insulation material. The connection device 40 includes a connection furnace 41, an intermediate heater 42, and a lift roller 43.

The connection furnace 41 is disposed between the forming furnace 31 and the slow cooling furnace 51 described below, and forms a connection chamber 41a that restricts the heat release of the glass ribbon G3 to be transported between them. The rapid cooling of the glass ribbon G3 can be prevented between the forming furnace 31 and the slow cooling furnace 51.

The intermediate heater 42 is disposed in the connection chamber 41a. The intermediate heater 42 is provided at plural intervals in the conveyance direction of the glass ribbon G3, and adjusts the temperature distribution in the conveyance direction of the glass ribbon G3. The intermediate heater 42 may also be divided in the width direction of the glass ribbon G3, so as to adjust the temperature distribution in the width direction of the glass ribbon G3.

The lift roller 43 is disposed in the connection chamber 41a. The lift roller 43 is rotationally driven by a motor or the like, lifts the glass ribbon G3 from the molten metal M, and transfers the glass ribbon G3 from the forming furnace 31 to the slow cooling furnace 51. A plurality of lift rollers 43 are provided at intervals in the conveyance direction of the glass ribbon G3.

The slow cooling device 50 cools the glass ribbon G3 formed in the forming device 30 slowly. The slow cooling device 50 includes a slow cooling furnace 51, a slow cooling heater 52, and a slow cooling roller 53.

The slow cooling furnace 51 forms a slow cooling chamber 51 a that slowly cools the glass ribbon G3. As the entrance from the slow cooling furnace 51 is directed toward the exit of the slow cooling furnace 51, the temperature of the slow cooling chamber 51a becomes lower.

The slow cooling heater 52 is disposed in the slow cooling chamber 51a. A plurality of slow cooling heaters 52 are provided at intervals in the conveyance direction of the glass ribbon G3, and adjust the temperature distribution in the conveyance direction of the glass ribbon G3. The slow cooling heater 52 can also be divided in the width direction of the glass ribbon G3, so as to adjust the temperature distribution in the width direction of the glass ribbon G3.

The slow cooling roller 53 is arranged in the slow cooling chamber 51a. The moderating roller 53 is rotationally driven by a motor or the like, so that The glass ribbon G3 is conveyed from the entrance of the slow cooling furnace 51 toward the exit of the slow cooling furnace 51. A plurality of slow cooling rollers 53 are provided at intervals in the conveyance direction of the glass ribbon G3.

The slow-cooled glass ribbon G3 in the slow-cooling device 50 is cut to a specific size by a cutter to obtain a glass plate as a product.

Moreover, the manufacturing apparatus of a glass plate can be various. For example, the glass plate manufacturing device may include a clarification device for defoaming the bubbles contained in the molten glass G2 in the molten glass transfer device 20.

[Manufacturing method of glass articles]

Next, a glass plate manufacturing method using the glass plate manufacturing apparatus having the above-mentioned configuration will be described with reference to FIG. 2. Fig. 2 is a flowchart showing a method for manufacturing a glass article according to the first embodiment. As shown in FIG. 2, the method for manufacturing a glass plate includes a melting step S10, a molten glass transfer step S20, a forming step S30, and a slow cooling step S50.

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

In the molten glass transfer step S20, the molten glass G2 is transferred from the melting device 10 to the molding device 30.

In the forming step S30, the molten glass G2 produced in the melting step S10 is formed into a glass ribbon G3 having a plate shape. 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-shaped 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 floating kiln 311.

In the slow cooling step S50, the glass ribbon G3 formed in the forming step S30 is slowly cooled.

The slow-cooled glass ribbon G3 is cut to a specific size by a cutter to obtain a glass plate as a product.

Furthermore, there are various methods for manufacturing glass plates. For example, the method for manufacturing a glass plate may include a bubble included in the molten glass G2 in the molten glass transfer step S20. Defoaming clarification step.

[Molten glass heating device]

<First Embodiment>

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

The molten glass heating device 210 includes a composite pipe structure 220 and a current heating unit 230. The composite pipe structure 220 includes a duct that forms a flow path through which the molten glass G2 passes. The electric heating unit 230 electrically heats the composite pipe structure 220.

The 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 communicates with the main pipe 1 inside. Here, the term “substantially perpendicular to the horizontal direction” means 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 communicates with the main pipe 1 inside.

In the structure of FIG. 3, the lower branch pipe 3 is an introduction pipe that introduces the molten glass G2 to the main pipe 1, and the upper branch pipe 2 is an exhaust pipe that discharges the molten glass G2 from the main pipe 1. The opposite constitutes.

The main pipe 1, the upper branch pipe 2 and the lower branch pipe 3 are hollow pipes made of platinum or platinum alloy. Specific examples of the platinum alloy include a platinum-gold alloy and a platinum-rhodium alloy. In addition, in the case of platinum or a platinum alloy, a reinforced platinum made by dispersing a metal oxide in platinum or a platinum alloy is also included. In this case, as the dispersed metal oxide, a metal oxide of group III, group IV, or group 13 in the periodic table represented by Al ₂ O ₃ , or ZrO ₂ or Y ₂ O ₃ may be mentioned.

In order to introduce current to the wall of such a hollow tube containing platinum, the upper end 1a of the main pipe 1, the lower end 1b of the main pipe 1, the lateral end portion 2a of the upper branch pipe 2, and the lower branch pipe 3 The lateral ends 3a are provided with the electrodes 4, 5, 6, and 7 described below.

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

In the electric heating section 230 which electrically heats the composite pipe structure 220 configured as described above, the electrode 4 is joined to the periphery of the upper end 1a of the main pipe 1, the electrode 5 is joined to the periphery of the lower end 1b of the main pipe 1, and the electrode 6 is joined to the upper section. The outer periphery of the lateral end portion 2 a of the branch pipe 2 and the electrode 7 are joined to the outer periphery of the lateral end portion 3 a of the lower branch pipe 3.

The electrodes 4, 5, 6, and 7 include a ring-shaped electrode 4a, 5a, 6a, 7a made of platinum or a platinum alloy, and a lead-out electrode joined to one end of the ring-shaped electrode 4a, 5a, 6a, 7a. 4b, 5b, 6b, 7b. The lead-out electrodes 4b, 5b, 6b, and 7b are connected to the following power sources 24A, 24B, and 24C. When the current is applied, current flows from the lead-out electrodes 4b, 5b, 6b, and 7b to the conduit through the ring-shaped electrodes 4a, 5a, 6a, and 7a. 1, 2, 3 flows.

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

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

Further, a first current supply path 21 is formed that connects the electrode (first electrode) 4 at the upper end 1a of the main pipe 1 and the electrode (second electrode) 5 at the lower end 1b and supplies a current. A second current supply path 22 is formed that connects the electrode 4 at the upper end 1a of the main pipe 1 with the electrode 6 (third electrode) at the lateral end 2a of the upper branch pipe 2 and supplies a current. A third current supply path 23 is formed to connect the electrode 5 at the lower end 1b of the main pipe 1 to the electrode (fourth electrode) 7 at the lateral end portion 3a of the lower branch pipe 3 and to supply a current.

The first current supply path 21 supplies current to the electrodes 5 and 4, the second current supply path 22 supplies current to the electrodes 4 and 6, and the third current supply path 23 supplies power to the electrodes 7 and 5. As a result, the composite pipe structure 220 is electrically heated by this flow.

In the energization heating unit 230, a first power supply 24A is provided (inserted) in the first current supply path 21, a second power supply 24B is provided in the second current supply path 22, and a third current supply path 23 is provided Third power source 24C. That is, the first power source 24A is electrically connected to the electrodes 5 and 4, the second power source 24B is electrically connected to the electrodes 4 and 6, and the third power source 24C is electrically connected to the electrodes 7 and 5.

Further, the energization heating unit 230 includes a current balancing mechanism 25 that performs a 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. Adjustment.

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

Here, the current balancing mechanism 25 has a current balancing function for the current levels of the single-phase AC current ia, the single-phase AC current ib, and the single-phase AC current ic generated by the power source 24A, 24B, and 24C. Make adjustments to balance the current levels between the power sources. As an adjustment of the current level, the phase of the current can also be adjusted.

The current balancing mechanism 25 includes, for example, a transformer including a plurality of coils capable of adjusting the turns ratio of single-phase AC between R, S, R, T, S, and T in a three-phase AC phase, and three-terminal bidirectional Silicon controlled switches, Automatic Current Regulator (ACR).

In addition, in FIG. 3, an example is described in which the current balancing mechanism 25 is separated from the power sources 24A, 24B, and 24C. However, the current balancing mechanism 25 and the power sources 24A, 24B, and 24C may be combined to form a power supply system. .

As an example, the current balancing mechanism 25 of this embodiment makes the phase difference between the single-phase AC current ia of the power source 24A, the single-phase AC current ib of the power source 24B, and the single-phase AC current ic of the power source 24C 2π / 3, 4π / 3 ways to adjust the current. If the phase difference is set in this way, the sum of the potential differences of the three power sources 24A, 24B, 24C is always fixed.

As a result, 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 supply 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 in the path 22 and the current ic flowing in the third current supply path 23 connecting the lower end 1b of the main pipe 1 and the lateral end portion 3a of the lower branch pipe 3 are controlled so as to be equal to each other.

When a uniform current is supplied to each of the current supply paths as described above, in FIG. 3, at the upper end (the upper end of the connection portion, the upper corner portion) Ja of the branch portion of the main pipe 1 and the upper branch pipe 2, since the first The currents supplied from the current supply path 21 and the second current supply path 22 repeatedly flow. Further, the upper end Ja of the branch portion is located at the shortest path of the current flowing from the upper end 1a of the autonomous pipe 1 to the upper branch pipe 2. Therefore, the upper end Ja of the branch portion becomes a portion where the current is concentrated.

As a result, the current at the upper end Ja of the branch portion may be concentrated, which may cause local heating.

Therefore, it is preferable to prevent local heating at the upper end Ja of the branch portion when the upper branch pipe 2 is electrically heated, so in this embodiment, the size of the composite pipe structure 220 is specified to reduce the concentration of current. . In detail, in the molten glass heating device 210 of this embodiment, the position of the upper branch pipe 2 can be appropriately set by setting the height (length) Hm of the composite pipe structure 220 relative to the main pipe 1 to the branch portion. It is easy and appropriate to perform the energization control in a manner that local heating is not generated at the upper end Ja.

Here, the cause of the specific local heating will be studied in terms of the size of the composite pipe structure 220.

When the composite tube structure 220 surrounding the molten glass G2 is electrically heated, P is set as heat (W), I is set as current (A), and R is set as resistance (Ω), the following formula: [数1) P = I ² × R ‧‧‧ (1)

Generates heat. Here, if H is the calorific value (J) and T is the time (sec), then [Number 2] H = P. T‧‧‧ (2)

Of heat.

At this time, the current flowing is set to V (V), and is as follows,

Here, the resistance refers to S as the cross-sectional area (m ² ) of the conductor (conduit), 1 to the length (m) of the conductor, and ρ to the specific resistance (resistivity) (Ω‧m) of the material. And the following formula is expressed,

If the inner diameter (inside diameter) of the catheter is set to D, the thickness of the catheter is set to t, and it is applied to equation (4), then

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

Since π is the circumference, ρ is the specific resistance of the material, and t is the thickness, the "2ρ / πt" of formula (6) is fixed in all the conduits 1, 2, and 3. Therefore, in the composite pipe structure 220 of this embodiment, the ratio of "1 / D" of the portion where the current flows is compared, so that the resistance value R of the catheter and the value of the flowing current can be compared. The amount of current is used to predict local heat generation.

In the present embodiment, in order to prevent local heat generation at the upper end Ja of the branch portion, the sizes and connection positions (minutes) of the respective conduits in the composite pipe structure 220 are set as follows. Support position). In addition, these dimensions are prescribed | regulated considering the calculation result of the temperature of a following example.

In addition, the dimensions of the ring-shaped electrodes 4, 5, 6, 7 and the cylinders of the tubes 1, 2, 3 are provided on the upper end 1a, the lower end 1b of the main pipe, and the lateral ends 2a, 3a of the branch pipes 2, 3. Compared with the size of the body part, it is so small that it can be ignored. Therefore, the resistances of the electrodes 4, 5, 6, and 7 are set to be as small as negligible compared with the resistance of the cylindrical body portion of the catheters 1, 2, and 3.

FIG. 4 is a perspective perspective view illustrating the position of the upper branch pipe 2 relative 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 the upper branch portion (the portion higher than the upper end Ja of the branch portion) in the main pipe 1.

In the present embodiment, in order to appropriately set the position of the upper branch pipe 2 with respect to the main pipe 1, it is preferable to specify the position (distance h) of the upper end 1a of the autonomous pipe 1 to the upper end Ja of the branch portion as follows.

In this embodiment, it is preferable to satisfy "0.4 <(the resistance of the current flowing between the upper end 1a of the main pipe 1 and the upper end Ja of the branch portion (γ), and the branch portion J and the side ends of the upper branch tube 2 The total resistance of the current flowing between the parts 2a (β) / the resistance of the current flowing between the upper end 1a and the lower end 1b of the main pipe 1 (α)) <0.8 ".

Here, [the resistance of the current flowing between the upper end 1a of the main pipe 1 and the upper end Ja of the branch portion (γ)] and [between the branch portion J of the upper branch tube 2 and the side end portion 2a (β The total value of the resistance of the flowing current] divided by [the resistance of the current flowing between the upper end 1a and the lower end 1b of the main pipe 1] is defined as the ratio A.

Here, the branch portion J of the upper branch pipe 2 refers to a connection portion between the main pipe 1 and the upper branch pipe 2. For example, in a case where 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 as the connection portion has a substantially circular shape.

The ratio A is more preferably greater than 0.45, and even more preferably greater than 0.5. The ratio A is more preferably less than 0.75, and even 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 with respect to the main pipe 1 and extends in the horizontal direction, and the electrode 6 at the lateral end portion 2a is provided vertically with respect to the upper branch pipe 2 In this case, the ratio A is expressed by the following formula.

The height (length) of the main pipe 1 is set to Hm, the inner diameter of the main pipe 1 is set to D1, and the length of the upper branch pipe 2 (that is, the length of the bus bar on the peripheral surface of the cylindrical upper branch pipe 2) is set When L is the internal diameter of the upper branch pipe 2 as D2, and the distance from the upper end 1a of the autonomous pipe 1 to the upper end Ja of the branch section of the upper branch pipe 2 is h, an upper branch pipe is provided relative to the main pipe 1. The position of 2 can be set as:

In this case, it is also preferable to satisfy 0.4 <the ratio A = ((h / D1) + (L / D2)) / (Hm / D1) <0.8.

Here, the upper branch pipe 2 may be inclined without extending in the horizontal direction. In a case where the upper branch pipe 2 is inclined without extending in the horizontal direction and the electrode 6 of the lateral end portion 2a is provided in the vertical direction, it is not necessary to correct by the formula (7).

The ratio A is not limited to the formula (7). For example, when the upper branch pipe 2 is inclined without extending in the horizontal direction and the electrode 6 of the lateral end portion 2a is not provided in the vertical direction, the cross-sectional area S and length L of the upper branch pipe 2 (β) are based on According to the situation of the relationship between the angle of the branch and the angle of the end, it is necessary to correct the addition or subtraction by formula (7).

Regardless of whether the upper branch pipe 2 is horizontal or inclined, the above ratio A means "[the resistance of the current flowing through the upper part of the branch γ in the main pipe 1] and [the current flowing through the upper branch pipe 2 (β) The ratio of the current resistance] divided by [the resistance of the current flowing through the entire α of the main pipe 1].

By setting the ratio to 0.4 <a ratio A <0.8 in this way, local heating generated at the upper end Ja of the branch portion can be suppressed, and the molten glass G2 can be uniformly heated in the composite pipe structure 220, so that heterogeneity can be suppressed.

In the present invention, the position where the upper branch pipe 2 is provided with respect to the upper end 1a of the main pipe 1 preferably satisfies the following formula. Here, in FIG. 3, the lower end Jb of the branch portion is the lower end (lower corner portion) of the connection portion between the main pipe 1 and the upper branch pipe 2.

"0.55 <(The shortest path of the current flowing from the upper end 1a of the autonomous pipe 1 to the upper end Ja of the branch through the main pipe 1 and the uppermost part of the inner peripheral part of the upper branch pipe 2 from the upper end Ja of the branch pipe 2 along the cylindrical upper branch pipe 2 The total path of the current flowing from the busbar direction to the side end 2a of the upper branch pipe 2 SD / the shortest path of the current flowing from the upper end 1a of the autonomous pipe 1 to the lower end Jb of the branch through the main pipe 1 and the lower end Jb of the branch The total lowermost part of the inner peripheral part of the upper branch pipe 2 in the direction of the busbar of the cylindrical upper part branch pipe 2 toward the lateral end portion 2a of the upper branch pipe 2 (total LD) <0.77 ''

Here, the above-mentioned "[the shortest path of the current flowing from the upper end 1a of the autonomous tube 1 to the upper end Ja of the branching portion through the main pipe 1 and the uppermost portion of the inner peripheral portion of the upper branching tube 2 from the upper end Ja of the branching portion 2 to a cylindrical shape The total SD of the path of the current flowing from the direction of the busbar of the partial branch pipe 2 to the side end 2a of the upper branch pipe 2 is divided by [the shortest path of the current flowing from the upper end 1a of the autonomous pipe 1 through the main pipe 1 to the lower end Jb of the branch, And the total LD obtained from the path of the current flowing from the lower end Jb of the branched portion through the lowermost part of the inner peripheral portion of the upper branched tube 2 in the direction of the busbar of the cylindrical upper branched branch tube 2 to the side end 2a of the upper branched tube 2]. "Ratio" is defined as ratio B.

Since the main pipe 1 is arranged substantially perpendicular to the horizontal direction, the upper end 1 a of the current main tube 1 flows through the main pipe 1 to the upper end Ja of the branch portion in a substantially vertical direction.

In addition, the upper end 1a of the current autonomous tube 1 flows through the main tube 1 to the side end (left or right end) of the connection portion between the main tube 1 and the upper branch tube 2 (that is, the branch portion J of the upper branch tube 2) in a substantially vertical direction. , Flows from the side end of the branch J along the arc of the branch J to the lower end Jb of the branch move.

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 direction of the generatrix of the branch pipe 2 in the horizontal cylindrical shape is the horizontal direction.

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

As a specific example, in a case where 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 at the lateral end portion 2a is provided vertically with respect to the upper branch pipe 2 At this time, since the length of the bus bar of the branch pipe 2 above the straight cylindrical shape is equal to the length L of the upper branch pipe 2, the ratio B can be set as:

In this case, it is also preferable to satisfy 0.55 <the ratio B = (h + L) / (h + (5/4) D2 + L) <0.77.

Furthermore, as shown in FIG. 4, the current passing through the path SD (h + L) passes through the upper end Ja of the branch portion of the main pipe 1 and the upper branch pipe 2, and the current passing through the path LD (h + (5/4) D2 + L) passes. The lower end of the branch Jb.

Here, the upper branch pipe 2 may be inclined without extending in the horizontal direction. If the upper branch pipe 2 is inclined without extending in the horizontal direction, and the electrode 6 of the lateral end portion 2a is provided in the vertical direction, it is a circular side end portion 2a that becomes the bottom surface of the cylinder of the upper branch tube 2. The oblique cylindrical shape intersecting obliquely with the generatrix of the circumferential surface need not be corrected by the formula (8).

The ratio B is not limited to the formula (8). For example, when the upper branch pipe 2 is inclined without extending in the horizontal direction and the electrode 6 of the lateral end portion 2a is not provided in the vertical direction, the length L of the upper branch pipe 2 (β) is based on the angle according to the branch And the relationship between the angles of the ends, there may also be corrections that need to be added or subtracted by equation (8). Happening. For example, it is the case where the straight cylinder shape which the base surface and the peripheral surface of a circumferential surface intersect at right angles is inclined, and it cuts and connects.

In this way, "[The shortest path of the current flowing from the upper end 1a of the autonomous tube 1 to the upper end Ja of the branch portion through the main pipe 1 and the uppermost part of the inner peripheral portion of the upper branch tube 2 from the upper end portion of the branch portion Ja to the upper branch tube 2 along the cylindrical upper part The total SD of the path of the current flowing from the direction of the bus bar 2 to the side end 2a of the upper branch pipe 2 is divided by [the shortest path of the current flowing from the upper end 1a of the autonomous pipe 1 through the main pipe 1 to the lower end Jb of the branch, and The lower end of the branch Jb passes the total LD of the path of the current flowing through the lowermost part of the inner peripheral portion of the upper branch pipe 2 in the direction of the busbar of the cylindrical upper branch pipe 2 toward the side end 2a of the upper branch pipe 2]. " The ratio B includes both the case where the upper branch pipe 2 is horizontal (in the case of a straight cylindrical shape) and the case where it is inclined (in the case of a straight cylindrical shape and an oblique cylindrical shape).

By setting 0.55 <the ratio B <0.77 in this way, it is possible to suppress the generation of a temperature difference between above and below the inside of the pipe of the upper branch pipe 2, and to suppress the temperature difference of the molten glass G2 in the composite pipe structure 220. produce.

The relationship between changes in the ratios A and B when the size of the composite pipe structure 220 and the installation position of the upper branch pipe 2 are changed is shown below.

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

If the height Hm of the main pipe 1 becomes low, the ratio B remains unchanged, but the ratio β of the portion above the branch becomes larger, so the ratio A becomes larger.

When the length L of the upper branch pipe 2 becomes longer, either of the ratio A and the ratio B becomes larger.

When two or more dimensions such as the distance h and the height Hm are changed, the ratio A and the ratio B are changed in accordance with the ratio of the change.

When the length of the duct is set to satisfy 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, and even more preferably 1100 mm or more. The height Hm is more preferably 2700 mm or less, and even more preferably 2400 mm or less. The length L is more preferably 150 mm or more, and even more preferably 250 mm or more. The length L is more preferably 1300 mm or less, and even more preferably 1100 mm or less. If the height Hm of the main pipe 1 is 3000 mm or less, the resistance of the current of the main pipe 1 can be suppressed, and the molten glass G2 can be sufficiently heated. 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 can be 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, and even more preferably 150 mm or more. The inner diameter D1 is more preferably 450 mm or less, and even more preferably 400 mm or less.

In order to set the upper branch pipe 2 above the main pipe 1 (more than half), the inner diameter D2 of the upper branch pipe 2 must be shorter than one and a half of the height Hm of the main pipe. The inner diameter D2 of the upper branch pipe 2 is preferably 50 mm to 500 mm. . The inner diameter D2 is more preferably 100 mm or more, and even more preferably 150 mm or more. The inner diameter D2 is more preferably 450 mm or less, and even more preferably 400 mm or less.

In order to arrange the upper branch pipe 2 above the main pipe 1 (from more than half), the distance h from the upper end 1a of the autonomous pipe 1 to the upper end Ja of the branch pipe of the upper branch pipe 2 must be shorter than half of the height Hm of the main pipe 1. It is preferably 50mm ~ 500mm. The distance h is more preferably 100 mm or more, and even more preferably 150 mm or more. The distance h is more preferably 450 mm or less, and even more preferably 400 mm or less.

If the distance h is too short, the upper branch pipe 2 is close to the upper end 1a of the main pipe 1. Therefore, bubbles may be trapped during the transportation of the molten glass G2. If the distance h is too long, the temperature of the upper end Ja of the branch portion becomes easy. It can be raised, so it is possible to suppress the occurrence of bad conditions by setting an appropriate distance h.

Further, in the glass manufacturing apparatus, a stirrer for stirring the molten glass G2 may be provided on the main pipe 1 of the composite pipe structure 220. In the case where a stirrer is provided in the main pipe 1, The homogenization of the state (temperature, homogeneity, etc.) of the molten glass G2 can be improved.

When the above configuration is viewed from above, the lower branch pipe 3 is disposed on the side opposite to the main pipe 1 on the side opposite to the upper branch pipe 2, but the upper branch pipe 2 and the lower branch pipe 3 need not be disposed at 180 degrees. On the opposite side, it can also be set to a specific angle of 45 degrees or more.

In the above description, the case where the branch pipes 2 and 3 branch horizontally from the main pipe 1 has been described, but the branch pipes 2 and 3 may be branched by tilting the main pipe 1 within a range that does not become vertical. In this case, it is also preferable to constitute the composite pipe structure 220 so as to satisfy the ratio as described above.

<Second Embodiment>

In the present embodiment, a case where two molten glass heating devices are arranged in parallel inside the molten glass transfer device 20 shown in FIG. 1 will be described.

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

As in the structure of FIG. 3, in the composite pipe structure 220 of the molten glass heating device 210 described on the left side of FIG. 5, the lower branch pipe 3 is an introduction pipe on the inlet side that introduces the molten glass G2 to the main pipe 1. Part of the branch pipe 2 is a discharge pipe that discharges 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 introduction pipe that introduces the molten glass G2 discharged from the upper branch pipe 2 to the inlet side of the main pipe 1R, and the lower branch pipe 3R has been An outlet-side tube discharged through the molten glass G2 of the main pipe 1R. The lateral end portion 2c of the upper branch pipe 2R is disposed so as to face the lateral end portion 2a of the partial branch pipe 2 above the first molten glass heating device 210.

In the present embodiment, the current balancing mechanisms 25 and 25R are provided in the current heating section 230 of the first molten glass heating device 210 and the current heating section 260 of the second molten glass heating device 240, respectively. Therefore, the current heating is independent.地 控制。 Control.

The molten glass heating device (system) according to the embodiment of the present invention is not limited to the float method shown in FIG. 1 and FIG. 2, and can also be applied to the melting method or other glass article manufacturing methods.

Moreover, the glass article manufactured using the glass manufacturing apparatus equipped with the molten-glass heating apparatus of this invention is not limited to a glass plate, and may be various shapes.

The embodiments and the like of the molten glass heating device have been described above, but the present invention is not limited to the above embodiments and the like, and various changes and improvements can be made within the scope of the gist of the present invention described in the scope of the patent application.

[Example]

For the above-mentioned molten glass heating device, the dimensions were changed, and the surface temperature of the composite pipe structure was calculated by simulation (finite element method). Examples 1 to 7 below 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 device are as follows.

Head height Hm: 1000mm

Main tube inner diameter D1: 200mm

Branch tube length L: 450mm

Branch tube inner diameter D2: 200mm

Distance between upper end of main pipe and upper end of branch pipe: 220mm

In Examples 2 to 10, the dimensions of each part in the molten glass heating device of Example 1 were changed as shown in Table 1 indicating the temperature of the molten glass in the composite pipe structure in which the position of the upper branch pipe was changed with respect to the main pipe. .

In Table 1, T0 indicates the temperature of the central part of the main pipe 1, T1 indicates the temperature of the upper part of the main pipe 1 (the branch upper part γ), and T2 indicates the temperature of the upper end (corner part) of the branch of the main pipe 1 and the upper branch pipe 2. , And T3 represents the temperature of the lower end (corner) Jb of the branch portion of the main pipe 1 and the upper branch pipe 2.

Furthermore, the central portion of the main pipe 1 whose temperature T0 has been calculated means one of the heights Hm of the main pipe 1 Half-right vertical position.

As can be seen from Table 1, when the ratio A is 0.33 (Example 8) and 1.41 (Example 9), the temperature difference between the central portion of the main pipe 1 and the upper branch portion γ, and the central portion of the main pipe 1 and the upper end Ja of the branch portion <T1-T0 > And <T2-T0> exceed 20 ° C, respectively. When the ratio A is 0.80 (Example 10), the temperature differences <T2-T0> and <T3-T0> of the central portion of the main pipe 1 and the upper end Ja of the branch 1 and the lower portion Jb of the main pipe 1 exceed 20 ° C.

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

As can be seen from Table 1, when the ratio B is 0.44 (Example 8) and 0.77 (Example 9), the temperature difference between the central portion of the main pipe 1 and the upper branch portion γ, and the central portion of the main pipe 1 and the upper end Ja of the branch portion <T1 -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 Ja of the branch 1 and the central portion of the main pipe 1 and the lower ends of the branch portions Jb <T2-T0> and <T3-T0> respectively exceed 20 ° C.

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

When setting the size, it is more preferable to satisfy the above two ranges within the range of the above ratio A and ratio B.

When the range of both the ratio A and the ratio B is satisfied, as shown in Examples 1 to 7, the central portion and the upper branch portion γ of the main pipe 1 and the central portion and the branch portion of the main pipe 1 can be reduced. The temperature difference <T1-T0>, <T2-T0>, <T3-T0> between the upper end Ja, the central portion of the main pipe 1 and the lower end Jb of the branch portion is preferable.

[Industrial availability]

The molten glass heating device of the present invention can be used to electrically heat the main pipe and the branch pipe included in the composite pipe structure to the required temperature, so it can be applied to the heating of the flow path of the molten glass in the glass manufacturing device.

Claims (16)

A molten glass heating device includes a composite pipe structure through which molten glass passes, and an electric current heating unit for electrically heating the composite pipe structure, and the composite pipe structure includes: a main pipe, which is roughly relative to a horizontal direction. It extends vertically; an upper branch pipe branching from the main pipe above the main pipe; and a lower branch pipe branching from the main pipe to the lower side of the main pipe; the energized heating section includes an upper end disposed above the main pipe. A first electrode, a second electrode provided at a lower end of the main pipe, and a third electrode provided at a lateral end portion of the upper branch pipe are formed to supply a current between the first electrode and the second electrode. The first current supply path is formed with a second current supply path between the first electrode and the third electrode, and the composite tube structure satisfies 0.4 Resistance of the current flowing between the upper end and the upper end of the branch, and the resistance of the current flowing between the branch of the upper branch pipe and the side end Total / currents flowing in the resistance between the upper end of the lower end of the above-described respective competent) mode <0.8, the branch pipe disposed above the upper competent. For example, in the molten glass heating device of claim 1, wherein in the case of the composite pipe structure, the upper branch pipe is branched approximately perpendicularly from the main pipe, the height from the upper end to the lower end of the main pipe is set to Hm Set the inner diameter to D1, the length of the upper branch pipe to L, the inner diameter to D2, and the distance from the upper end of the main pipe to the upper end of the branch of the upper branch pipe to h. At the time, the upper branch pipe is configured for the main pipe in a manner such that 0.4 <((h / D1) + (L / D2)) / (Hm / D1) <0.8. The molten glass heating device of claim 1 or 2, wherein in the composite pipe structure, 0.55 <(the shortest path of the current flowing from the upper end of the main pipe to the upper end of the branch through the main pipe, and The total of the path of the current flowing through the upper end of the branch part through the innermost part of the upper branch pipe in the direction of the busbar of the cylindrical upper branch pipe toward the side end of the upper branch pipe / from the above-mentioned supervisor The shortest path of the current flowing from the upper end through the main pipe to the lower end of the branch, and from the lower end of the branch through the inner peripheral portion of the upper branch pipe to the upper branch pipe in the direction of the bus of the cylindrical upper branch pipe. The total of the paths of the current flowing at the lateral end portions) <0.77, and the upper branch pipe is arranged on the upper end of the main pipe. For example, if the molten glass heating device of claim 1 or 2 is used, in the composite pipe structure, when the upper branch pipe is branched from the main pipe substantially vertically, the length of the upper branch pipe is set to L, and When the diameter is set to D2, and the distance from the upper end of the main pipe to the upper end of the branch of the upper branch pipe is set to h, 0.55 <(h + L) / (h + (5/4) D2 + L) <0.77, the upper branch pipe is arranged on the upper end of the main pipe. For example, the molten glass heating device of claim 2, wherein the height Hm from the upper end to the lower end of the main pipe is 500 mm to 3000 mm. For example, the molten glass heating device of claim 2, wherein the length L of the upper branch pipe is 50 mm to 1500 mm. For example, the molten glass heating device of claim 2, wherein the inner diameter D1 of the main pipe is 50 mm to 500 mm. For example, the molten glass heating device of claim 2, wherein the inner diameter D2 of the upper branch pipe is 50 mm to 500 mm and shorter than one and a half of the height Hm of the main pipe. For example, the molten glass heating device of claim 2, wherein the distance h from the upper end of the main pipe to the upper end of the branch of the upper branch pipe is 50 mm to 500 mm, and is shorter than half of the height Hm of the main pipe. The molten glass heating device according to claim 1 or 2, wherein the energization heating section includes a current balancing mechanism that adjusts a current flowing through the first current supply path and the second current supply path. For example, the molten glass heating device of claim 10, wherein a first power supply is provided in the first current supply path, and a second power supply is provided in the second current supply path, and the current balancing mechanism supplies the first power supply and the second power supply. The phase of the current is adjusted. The molten glass heating device according to claim 10, further comprising a fourth electrode provided at a lateral end portion of the lower branch pipe, and forming the second electrode and the fourth electrode that supply a current to the lower end of the main pipe. In the third current supply path between the electrodes, the current balancing mechanism adjusts a current flowing through the first current supply path, the second current supply path, and the third current supply path. The molten glass heating device according to claim 1 or 2, wherein the composite pipe structure is made of platinum or a platinum alloy. A glass manufacturing apparatus comprising the molten glass heating apparatus according to any one of claims 1 to 13. The glass manufacturing device according to claim 14, wherein the glass manufacturing device includes a first molten glass heating device composed of the molten glass heating device and a second molten glass heating device composed of the molten glass heating device, and melting in the first melting glass. In the glass heating apparatus, the lower branch pipe is a pipe introduced to the inlet side of the molten glass, and in the second molten glass heating apparatus, the lower branch pipe is a pipe on an outlet side to discharge the molten glass, and the upper branch pipe is The lateral end portion is disposed so as to face the lateral end portion of the upper branch pipe of the first molten glass heating device. A method for manufacturing a glass article, which uses a glass manufacturing apparatus as claimed in claim 14 or 15, and includes the following steps: heating the glass raw material to obtain a molten glass; and forming the above-mentioned molten glass and slowly cooling to obtain a glass article .