JP2021169383A - Manufacturing method of glass article and manufacturing apparatus of glass article - Google Patents

Abstract

To efficiently heat a molten glass transferred inside a transfer device by energizing the transfer device.SOLUTION: A manufacturing method of a glass article includes a transfer step of transferring a molten glass Gm using a transfer device 2. A stirring tank 5 included in the transfer device 2 includes a first electrode 18 and a second electrode 19 and a third electrode 20 which are arranged in this order from an upstream side to a downstream side along its transfer route. In the transfer step, a first AC current i1 is supplied to a first part of the stirring tank 5 positioned between the first electrode 18 and the second electrode 19, and a second AC current i2 is supplied to a second part of the stirring tank 5 positioned between the second electrode 18 and a third electrode 20. In supplying these currents, when a maximum value of the first AC current i1 is A, a maximum value of the second AC current i2 is B, and a maximum value of a third AC current i3 flowing in the second electrode 18 is C, a phase difference between the first AC current i1 and the second AC current i2 is adjusted such that the third AC current i3 satisfies a relation of (A2+B2+AB)1/2≤C.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for producing a glass article and an apparatus for producing a glass article.

The method for manufacturing a glass article includes a transfer step of transferring the molten glass produced in the melting furnace to a molding apparatus using a transfer device and a molding step of molding a glass article such as flat glass from the molten glass using the molding apparatus. (See, for example, Patent Document 1).

The above transfer device is provided with a plurality of electrodes at intervals from the upstream side to the downstream side in order along the transfer path, and by energizing between these electrodes, the inside of the transfer device is transferred. The molten glass is heated (see, for example, Patent Documents 2 and 3). The transfer device includes, for example, a clarification tank, a stirring tank, a state adjusting tank (pot), and the like.

Japanese Unexamined Patent Publication No. 2016-88754 Japanese Unexamined Patent Publication No. 2012-10970 Japanese Unexamined Patent Publication No. 2012-116693

By the way, if a plurality of electrodes provided in the transfer device are the first electrode, the second electrode, and the third electrode in this order from the upstream side to the downstream side along the transfer path of the transfer device, in the transfer step, for example, the first electrode The first AC current is supplied to the first part of the transfer device located between the second electrode and the second electrode, and the second AC current is supplied to the second part of the transfer device located between the second electrode and the third electrode. May be supplied. In this case, the second electrode is a common electrode used both when supplying the first alternating current to the first part of the transfer device and when supplying the second alternating current to the second part of the transfer device. .. Therefore, in the second electrode, the first alternating current and the second alternating current cancel each other out, which may cause a problem that the molten glass around the second electrode cannot be heated efficiently.

An object of the present invention is to efficiently heat the molten glass transferred inside the transfer device by energizing the transfer device.

The present invention, which was devised to solve the above problems, is a method for manufacturing a glass article including a transfer step of transferring molten glass using a transfer device, in which the transfer device is along a transfer path of the transfer device. A first electrode, a second electrode, and a third electrode are provided in order from the upstream side to the downstream side. A current is supplied, a second AC current is supplied to the second part of the transfer device located between the second electrode and the third electrode, the maximum value of the first AC current is A, and the maximum value of the second AC current. B, and when the maximum value of the third AC current flowing through the second electrode due to the current supply to the transfer device is C, the ^{relationship that the third AC current is (A 2} + B ² + AB) ^1/2 ≤ C is established. It is characterized in that the phase difference between the first alternating current and the second alternating current is adjusted so as to satisfy the requirements.

By adjusting the phase difference between the first alternating current and the second alternating current in this way, when the first alternating current is supplied to the first part of the transfer device and the second alternating current is supplied to the second part of the transfer device. The magnitude of the third alternating current flowing through the second electrode (common electrode) used for both supply can be easily and surely increased. Then, if the phase difference between the first alternating current and the second alternating current is adjusted so that the third alternating current satisfies the relationship of the above equation, the third alternating current flowing through the second electrode becomes large, and the third alternating current flows. The molten glass around the two electrodes can be heated efficiently.

In the above configuration, when the maximum value of the first alternating current is A, the maximum value of the second alternating current is B, and the maximum value of the third alternating current is C, the relationship is that the third alternating current is A + B = C. It is preferable to adjust the phase difference between the first alternating current and the second alternating current so as to satisfy the above conditions.

In this way, the third alternating current flowing through the second electrode becomes the largest, so that the molten glass around the second electrode can be heated very efficiently.

In the above configuration, the transfer device includes a stirring tank, which is provided on a main body having a bottom extending in the vertical direction and a side wall at the lower part of the main body in order to transfer the molten glass in the main body to the next step. The first electrode is provided on the main body portion above the outlet of the main body to which the outflow portion is connected, and the second electrode is below the outlet and the main body portion. The third electrode may be provided in the outflow portion.

By doing so, the lower end portion of the main body portion where the second electrode is provided, that is, the periphery of the bottom portion of the main body portion is efficiently heated. Therefore, the flow of the molten glass around the bottom of the main body is improved. That is, a glass stagnant layer is likely to be generated around the bottom of the main body as the fluidity of the molten glass decreases, which can be suppressed. Here, the glass stagnation layer may contain foreign glass having a composition different from that of the molten glass that normally flows in the main body. When such foreign glass is mixed in the molten glass that flows normally, it can become a defect of the manufactured glass article. Therefore, from the viewpoint of producing a high-quality glass article, it is preferable to suppress the generation of a glass stagnant layer around the bottom of the main body as described above.

In the above configuration, the stirring tank further includes a discharge portion provided at the bottom of the main body portion for discharging the molten glass in the main body portion and a fourth electrode provided at the discharge portion, and the second electrode is provided in the transfer step. The fourth alternating current may be supplied to the discharge portion located between the fourth electrode and the fourth electrode.

In this way, since the discharge portion provided at the bottom of the main body is heated, the periphery of the bottom of the main body is heated more efficiently. Therefore, the generation of the glass stagnant layer can be suppressed more reliably.

In the above configuration, when the maximum value of the first alternating current is A, the maximum value of the second alternating current is B, the maximum value of the third alternating current is C, and the maximum value of the fourth alternating current is D. It is preferable to adjust the phase difference between the first alternating current, the second alternating current, and the fourth alternating current so that the three alternating currents ^{satisfy the relationship (A 2} + B ² + D ² + AB + AD + 2BD) ^{1/2 ≤ C.}

If the phase difference between the first alternating current, the second alternating current, and the fourth alternating current is adjusted so that the third alternating current satisfies the relationship of the above equation, the third alternating current flowing through the second electrode Becomes larger, and the periphery of the bottom of the main body is heated more efficiently. Therefore, the generation of the glass stagnant layer can be suppressed more reliably.

In the above configuration, the transfer device includes a state adjusting tank, the state adjusting tank includes a main body portion having a bottom extending in the vertical direction, and an inflow portion provided on the side wall of the upper part of the main body portion, and the first electrode is , The second electrode is provided in the main body portion above the inflow port of the main body to which the inflow portion is connected, and the third electrode is provided in the main body portion below the inflow port. It may have been done.

By doing so, the upper part of the main body portion provided with the second electrode is efficiently heated. Therefore, the temperature near the liquid level of the molten glass located at the upper part of the main body becomes high. That is, in the vicinity of the liquid level of the molten glass, a glass stagnant layer and devitrification are generally likely to occur, which can be suppressed.

The present invention, which was devised to solve the above problems, is a device for manufacturing a glass article including a transfer device for transferring molten glass, and is provided in order from the upstream side to the downstream side along the transfer path of the transfer device. The first electrode, the second electrode, the third electrode, the first power supply that supplies the first AC current to the first part of the transfer device located between the first electrode and the second electrode, the second electrode, and the second electrode. The second power supply that supplies the second AC current to the second part of the transfer device located between the three electrodes, the maximum value of the first AC current is A, the maximum value of the second AC current is B, to the transfer device. When the maximum value of the third AC current flowing through the second electrode is C, the third AC current satisfies the relationship of ^{(A 2} + B ² + AB) ^{1/2 ≤ C.} It is characterized by including a phase adjusting unit for adjusting the phase difference between the AC current and the second AC current.

In this way, it is possible to enjoy the same effect as the corresponding configuration described above.

According to the present invention, the molten glass transferred inside the transfer device can be efficiently heated by energizing the transfer device.

It is a side view which shows the manufacturing apparatus of the glass article which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the periphery of the stirring tank of the manufacturing apparatus of the glass article which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the periphery of the stirring tank of the manufacturing apparatus of the glass article which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the periphery of the state adjustment tank of the manufacturing apparatus of the glass article which concerns on 3rd Embodiment of this invention. It is a graph which shows the change of the 3rd alternating current which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, duplicate description may be omitted by assigning the same reference numeral to the corresponding component in each embodiment. When only a part of the configuration is described in each embodiment, the configurations of the other embodiments described above can be applied to the other parts of the configuration. Further, not only the combination of the configurations specified in the description of each embodiment but also the configurations of a plurality of embodiments can be partially combined even if the combination is not specified.

(First Embodiment)
As shown in FIG. 1, in the first embodiment, a glass article manufacturing apparatus and a glass article manufacturing method are illustrated. The glass article manufacturing apparatus according to the present embodiment includes a melting furnace 1, a transfer device 2, and a molding device 3 in this order from the upstream side to the downstream side in the transfer direction of the molten glass Gm. Further, the method for producing a glass article according to the present embodiment includes a melting step, a transfer step, and a molding step in order. The method for manufacturing the glass article will be described together with the description of the configuration of the glass article manufacturing apparatus.

The melting furnace 1 is for carrying out a melting step of continuously forming molten glass Gm. Examples of the heating method of the molten glass Gm (or glass raw material) in the melting furnace 1 include a method of heating only by energization heating (total electrofusion method), a method of heating only by combustion of gas fuel, energization heating and gas fuel. A method of heating in combination with combustion can be adopted.

In the present embodiment, the molten glass Gm is made of non-alkali glass. The glass composition of the non-alkali glass is, for example, SiO ₂ 50 to 70%, Al ₂ O ₃ 12 to 25%, B ₂ O _{30 to} 12%, Li ₂ O + Na ₂ O + K ₂ O (Li _{2) in terms of glass composition.} The total amount of O, Na ₂ O and K ₂ O) 0 to less than 1%, MgO 0 to 8%, CaO 0 to 15%, SrO 0 to 12%, and BaO 0 to 15%. The electrical resistivity of the molten glass Gm made of non-alkali glass is generally high, and is, for example, 100 Ω · cm or more at a heating temperature of 1500 ° C. of the melting furnace 1.

The molten glass Gm is not limited to non-alkali glass, and may be, for example, soda glass, soda-lime glass, borosilicate glass, aluminosilicate glass, alkali-containing glass, or the like.

The transfer device 2 is for carrying out a transfer step of transferring the molten glass Gm from the melting furnace 1 to the molding device 3, and has a transfer path (space) inside for transferring the molten glass Gm. Consists of tubes. Here, the term transfer tube includes a tube having a tubular structure as well as a tube having a tank-like (container-like) structure.

In the present embodiment, the transfer device 2 includes a clarification tank 4, a stirring tank 5, a state adjusting tank (pot) 6, and connecting pipes 7 to 10 connecting each of these parts. That is, the transfer step includes a clarification step, a stirring step, and a state adjusting step.

The clarification tank 4 is for carrying out a clarification step of clarifying (defoaming) the molten glass Gm supplied from the melting furnace 1 by the action of a clarifying agent or the like.

The stirring tank 5 is for carrying out a homogenization step in which the molten glass Gm clarified in the clarification tank 4 is stirred by a stirring blade (stirrer) 5a and homogenized.

The state adjusting tank 6 is for carrying out a state adjusting step of adjusting the molten glass Gm stirred in the stirring tank 5 to a state suitable for molding. The state adjusting tank 6 is a tank without mechanical stirring means such as a stirring blade, and is located on the most downstream side when the transfer device 2 has a plurality of tanks as described above. In other words, the state adjusting tank 6 is a tank that adjusts the flow rate, viscosity, and the like of the molten glass Gm immediately before the molding apparatus 3.

The connecting tubes 7 to 10 are formed of, for example, a cylindrical body (for example, a cylindrical body) made of platinum or a platinum alloy, and transfer the molten glass Gm in the lateral direction (substantially horizontal direction). In the present embodiment, in the transfer device 2, the connecting pipe 7 located at the most upstream portion and the connecting pipe 9 connecting the stirring tank 5 and the state adjusting tank 6 are located on the downstream side above the upstream side. It is inclined to.

The molding device 3 is for carrying out a molding step of molding the molten glass Gm transferred by the transfer device 2 into a desired shape. In the present embodiment, the molding apparatus 3 includes a molded body that continuously molds the glass ribbon G from the molten glass Gm by the overflow down draw method.

The molding apparatus 3 may implement another down-draw method such as a slot down-draw method or a known molding method such as a float method.

In the case of the overflow down draw method, the molten glass Gm supplied to the forming apparatus 3 overflows from the groove formed at the top of the forming apparatus 3, and then the molten glass Gm forms a wedge-shaped cross section on both sides of the forming apparatus 3. It travels and joins at the lower end. As a result, the plate-shaped glass ribbon G is continuously formed from the molten glass Gm. The molded glass ribbon G is slowly cooled (annealed), cooled, and then cut to a predetermined size to produce flat glass as a glass article.

The manufactured flat glass has a thickness of, for example, 0.01 to 10 mm (preferably 0.1 to 3 mm), and is used for panel displays such as liquid crystal displays and organic EL displays, substrates for organic EL lighting, solar cells, and protection. Used for covers.

As shown in FIG. 2, the stirring tank 5 includes a main body portion 11, an inflow portion 12, and an outflow portion 13.

The main body 11 is a tubular body with a bottom extending in the vertical direction, and has a stirring blade 5a inside thereof. By rotating the stirring blade 5a around an axis, the molten glass Gm in the main body 11 can be stirred.

The main body 11 has an inflow port 14 on the upper side wall and an outflow port 15 on the lower side wall.

A cylindrical inflow portion 12 extending in the lateral direction is connected to the inflow port 14. A connecting pipe 8 is connected to the upstream end of the inflow portion 12. That is, the molten glass Gm is transferred from the previous process (in the present embodiment, the clarification tank 4) into the main body 11 through the inflow section 12.

A cylindrical outflow portion 13 extending in the lateral direction is connected to the outflow port 15. A connecting pipe 9 is connected to the downstream end of the outflow portion 13. That is, the molten glass Gm in the main body 11 is transferred to the next step (in this embodiment, the state adjusting tank 6) through the outflow portion 13.

In the present embodiment, a discharge port 16 is provided at the bottom of the main body portion 11, and a cylindrical discharge portion (drain) 17 extending in the vertical direction is connected to the discharge port 16. At the time of manufacturing the glass article, the discharge unit 17 is closed by the solidified glass Gx solidified in the discharge unit 17. On the other hand, when the molten glass Gm is discharged, the molten glass Gm in the main body 11 is discharged to the outside through the discharge unit 17 by heating the solidified glass Gx in the discharge unit 17 to soften and flow it.

The first electrode 18 is provided above the outlet 15 of the main body 11 (upper end of the main body 11 in the illustrated example) and below the outlet 15 of the main body 11 (bottom of the main body 11 in the illustrated example). (Lower end)) is provided with a second electrode 19. A third electrode 20 is provided at the outflow portion 13 (in the illustrated example, the downstream end of the outflow portion 13). Each of the electrodes 18 to 20 is formed of, for example, a ring-shaped flange portion made of platinum or a platinum alloy, and is joined to the outer peripheral surface of the stirring tank 5 at a predetermined position by welding or the like. Although not shown, each electrode 18 to 20 has a lead-out electrode (for example, made of platinum, platinum alloy, nickel or nickel alloy) for connecting current supply paths 21 and 23, which will be described later, and a cooling mechanism (for example, water cooling). Or air cooling).

Between the first electrode 18 and the second electrode 19, a first current supply path 21 for energizing the first portion (main body portion 11) of the stirring tank 5 located between the electrodes 18 and 19 is provided. Has been done. The first current supply path 21 is provided with a first power supply (voltage source) 22 for applying a voltage between the first electrode 18 and the second electrode 19. By applying a voltage from the first power supply 22, the first alternating current i1 is supplied to the main body 11.

A second current supply path 23 for energizing the second portion (outflow portion 13) of the stirring tank 5 located between the electrodes 19 and 20 is provided between the second electrode 19 and the third electrode 20. Has been done. The second current supply path 23 is provided with a second power supply (voltage source) 24 for applying a voltage between the second electrode 19 and the third electrode 20. By applying a voltage from the second power supply 24, the second alternating current i2 is supplied to the outflow portion 13. The second electrode 19 is a common electrode used in both the first current supply path 21 and the second current supply path 23.

The stirring tank 5 is provided with a phase adjusting unit 25 for adjusting the phase difference θ between the first alternating current i1 and the second alternating current i2. The phase adjusting unit 25 is connected to the first power supply 22 and the second power supply 24. The first power supply 22, the second power supply 24, and the phase adjusting unit 25 are composed of, for example, a three-phase AC power supply. In the case of a three-phase AC power supply, the phase difference θ between the first AC current i1 and the second AC current i2 can be adjusted by appropriately changing the connection terminals (for example, TR, RT, RS, SR, etc.).

The phase adjusting unit 25 sets the maximum value of the first alternating current i1 to A, the maximum value of the second alternating current i2 to B, and supplies the first alternating current i1 and the second alternating current i2 to the second electrode 19. When the maximum value of the alternating current i3 is C, the phase difference θ between the first alternating current i1 and the second alternating current i2 is set so that the third alternating current i3 satisfies the relationship of the following equation (1). It is configured to adjust. That is, in the method for manufacturing a glass article, in the transfer step (in the present embodiment, the stirring step included in the transfer step), the first alternating current i3 satisfies the relationship of the following formula (1). The phase difference θ between the alternating current i1 and the second alternating current i2 is adjusted.
(A ² + B ² + AB) ^1/2 ≤ C ... (1)

Here, i1 = Asinωt, i2 = Bsin (ωt + θ), and i3 = i1-i2 are defined. Note that ω is the angular velocity, t is the time, and θ is the phase difference of the second alternating current i2 with respect to the first alternating current i1. The phase difference θ is based on the phase of the first alternating current i1, but is not limited thereto. Since the direction of each current is defined in FIG. 2, when the base of the second electrode 19 (the junction with the main body 11) is considered as a branch point, the inflow current to the branch point is i1 and the inflow current from the branch point is i1. Since the outflow currents are i2 and i3, the third alternating current i3 is represented by "i1-i2" as described above according to Kirchhoff's law.

In this case, the third alternating current i3 can be expressed by the following equation (2) from the addition theorem of trigonometric functions.
i3 = Asin ωt-Bsin (ωt + θ)
= (A-Bcosθ) sinωt-Bsinθcosωt ... (2)

Further, the equation (2) can be expressed by the following equation (2)'from the composition formula of the trigonometric function.
i3 = {(A-Bcosθ) ² + B ² sin ² θ} ^1/2 sin (ωt-α)
= (A ² + B ² -2ABcosθ) ^1/2 sin (ωt-α) ... (2)'
^{However, sinα = Bsinθ / (A 2} + B 2 -2ABcosθ) is ^{1/2, cosα = (A-Bcosθ} ) / (A 2 + B 2 -2ABcosθ) ^1/2.

Since -1 ≤ sin (ωt-α) ≤ 1, the equation (2)'shows the maximum value when sin (ωt-α) = 1. That is, the maximum value C of the third alternating current i3 is expressed by the following equation (3).
C = (A ² + B ² -2ABcosθ) ^1/2 ... (3)

By adjusting the phase difference θ between the first alternating current i1 and the second alternating current i2 in this way, the magnitude of the third alternating current i3 flowing through the second electrode 12 can be easily and surely adjusted. Then, if the phase difference θ between the first alternating current i1 and the second alternating current i2 is adjusted so that the third alternating current i3 satisfies the relationship of the above equation (1), the third alternating current i3 flows through the second electrode 19. 3 The alternating current i3 becomes large, and the vicinity of the bottom of the second electrode 19 and the main body 11 can be efficiently heated. Therefore, the flow of the molten glass Gm around the bottom of the main body 11 becomes good. That is, in general, a glass stagnant layer containing foreign glass is likely to be generated around the bottom of the main body 11, but this can be suppressed.

It is more preferable that the phase adjusting unit 25 is configured to adjust the phase difference θ of the first alternating current i1 and the second alternating current i2 so as to satisfy the relationship of the following equation (4).
A + B = C ... (4)

Here, the phase difference θ is preferably 120 ° ≦ θ ≦ 240 ° (or −120 ° ≧ θ ≧ −240 °), and more preferably 180 °. The left side of the equation (1) is the value of the equation (3) when θ = 120 ° (or −120 °), and the left side of the equation (4) is θ = 180 ° (or −180 °). It is the value of the equation (3) at the time of.

The maximum value A of the first alternating current i1 and the maximum value B of the second alternating current i2 may be different values (for example, A> B) or may be the same value. Further, at least one of the maximum value A of the first alternating current i1 and the maximum value B of the second alternating current i2 is set together with the phase difference θ so as to satisfy the relationship of the above equation (1) or (4). You may adjust.

An electrode may be provided in the inflow portion 12, and the electrode of the inflow portion 12 and the first electrode 18 of the main body portion 11 may be further energized. In this way, heating of the inflow portion 12 and the upper end portion of the main body portion 11 is promoted.

Further, the energization heating method described in the present embodiment can also be applied to a stirring tank 5 in which a plurality of main body portions 11 are connected. In this case, it is preferable to connect one upper portion of two adjacent main body portions 11 and the other lower portion with a connecting pipe.

(Second Embodiment)
As shown in FIG. 3, in the second embodiment, a modified example of the stirring tank 5 is illustrated. Since the basic configuration of the stirring tank 5 is the same as that of the first embodiment, the differences from the first embodiment will be mainly described.

In the present embodiment, the fourth electrode 26 is provided at the lower end of the discharge portion 17. The position of the fourth electrode 26 may be any position of the discharge portion 17 as long as it is below the second electrode 19. However, from the viewpoint of expanding the heating region by energization of the discharge unit 17, it is preferable to provide the fourth electrode 26 at the lower end of the discharge unit 17.

Between the second electrode 19 and the fourth electrode 26, a third current supply path 27 for energizing the discharge portion 17 located between the electrodes 19 and 26 is provided. The third current supply path 27 is provided with a third power source (voltage source) 28 for applying a voltage between the second electrode 19 and the fourth electrode 26. By applying a voltage from the third power source 28, the fourth alternating current i4 is supplied to the discharge unit 17. The second electrode 19 is a common electrode used in all of the first current supply path 21, the second current supply path 23, and the third current supply path 27.

The phase adjusting unit 25 is connected to the first power supply 22, the second power supply 24, and the third power supply 28, and has a phase difference θ1 between the first alternating current i1 and the second alternating current i2, and the first alternating current i1 and the fourth alternating current. It is configured to adjust the phase difference θ2 of the current i4. The first power supply 22, the second power supply 24, the third power supply 28, and the phase adjusting unit 25 are composed of, for example, a three-phase AC power supply.

The phase adjusting unit 25 sets the maximum value of the first alternating current i1 as A, the maximum value of the second alternating current i2 as B, the maximum value of the third alternating current i3 as C, and the maximum value of the fourth alternating current i4 as D. In this case, the phase difference θ1 of the first alternating current i1 and the second alternating current i2 and the first alternating current i1 and the fourth alternating current i3 so that the third alternating current i3 satisfies the relationship of the following equation (5). It is configured to adjust the phase difference θ2 of the alternating current i4. That is, in the method for manufacturing a glass article, in the transfer step (in the present embodiment, the stirring step included in the transfer step), the first alternating current i3 satisfies the relationship of the following formula (5). The phase difference θ1 of the alternating current i1 and the second alternating current i2 and the phase difference θ2 of the first alternating current i1 and the fourth alternating current i4 are adjusted.
(A ² + B ² + D ² + AB + AD + 2BD) ^1/2 ≤ C ... (5)

Here, i1 = Asinωt, i2 = Bsin (ωt + θ1), i4 = Dsin (ωt + θ2), and i3 = i1-i2-i4 are defined. Note that ω is the angular velocity, t is the time, θ1 is the phase difference of the second AC current i2 with respect to the first AC current i1, and θ2 is the phase difference of the fourth AC current i4 with respect to the first AC current i1. The phase differences θ1 and θ2 are based on the phase of the first alternating current i1, but are not limited thereto. The third alternating current i3 is a current flowing through the second electrode 19 by supplying the first alternating current i1, the second alternating current i2, and the fourth alternating current i4.

In this case, the third alternating current i3 can be expressed by the following equation (6) from the addition theorem of trigonometric functions.
i3 = Asin ωt-Bsin (ωt + θ1) -Dsin (ωt + θ2)
= (A-Bcosθ1-Dcosθ2) sinωt
-(Bsinθ1 + Dsinθ2) cosωt ... (6)

Further, equation (6) can be expressed by the following equation (6)'from the composition formula of trigonometric functions.
i3 = {(A-Bcosθ1-Dcosθ2) ²
+ (Bsinθ1 + Dsinθ2) ² } ^1/2 sin (ωt−α) ・ ・ ・ (6)'
However, if r = {(A-Bcosθ1-Dcosθ2) ² + (Bsinθ1 + Dsinθ2) ² } ^1/2 , then sinα = (Bsinθ1 + Dsinθ2) / r and cosα = (A-Bcosθ1-Dcosθ2) / r.

Since -1 ≤ sin (ωt-α) ≤ 1, the equation (6)'shows the maximum value when sin (ωt-α) = 1. That is, the maximum value C of the third alternating current i3 is expressed by the following equation (7).
C = {(A-Bcosθ1-Dcosθ2) ²
+ (Bsinθ1 + Dsinθ2) ² } ^1/2 ... (7)

By adjusting the phase differences θ1 and θ2 between the first alternating current i1, the second alternating current i2, and the fourth alternating current i4 in this way, the magnitude of the third alternating current i3 flowing through the second electrode 12 can be simplified. And it can be adjusted reliably. Then, the phase differences θ1 and θ2 between the first alternating current i1, the second alternating current i2, and the fourth alternating current i4 are adjusted so that the third alternating current i3 satisfies the relationship of the above equation (5). For example, by utilizing the energization of the discharge unit 17, the third alternating current i3 flowing through the second electrode 12 becomes larger, and the vicinity of the bottom portion of the second electrode 12 and the main body portion 11 can be efficiently heated. Therefore, it is possible to more reliably suppress the generation of a glass stagnation layer around the bottom of the main body 11.

The phase adjusting unit 25 adjusts the phase differences θ1 and θ2 between the first alternating current i1, the second alternating current i2, and the fourth alternating current i4 so as to satisfy the relationship of the following equation (8). It is preferably configured.
A + B + D = C ... (8)

Here, the phase differences θ1 and θ2 are preferably 120 ° ≦ θ ≦ 240 ° (or −120 ° ≧ θ ≧ −240 °), and more preferably 180 ° (or −180 °). The left side of the equation (5) is the value of the equation (7) when θ1 = θ2 = 120 ° (or −120 °), and the left side of the equation (8) is θ1 = θ2 = 180 ° (or). It is the value of the equation (7) when −180 °).

The maximum value A of the first alternating current i1, the maximum value B of the second alternating current i2, and the maximum value D of the fourth alternating current i4 may be the same value, but are preferably different values (for example,). A> B> D). Further, the maximum value A of the first alternating current i1, the maximum value B of the second alternating current i2, and the fourth alternating current current are satisfied together with the phase differences θ1 and θ2 so as to satisfy the relationship of the above equation (5) or (8). At least one of the maximum values D of i4 may be adjusted.

The maximum value D of the fourth alternating current i4 is preferably set to such a size that the solidified glass Gx of the discharge unit 17 does not soften and flow, that is, the molten glass Gm does not flow out from the discharge unit 17. On the other hand, when the molten glass Gm in the main body 11 is discharged to the outside through the discharge unit 17, it is preferable that the maximum value of the fourth alternating current i4 is larger than the maximum value D at the time of manufacturing the glass article.

(Third Embodiment)
As shown in FIG. 4, in the third embodiment, the state adjusting tank 6 is illustrated.

The state adjusting tank 6 has a cylindrical main body 31 extending in the vertical direction, an inflow port 32 of molten glass Gm provided in the upper part of the main body 31, and a flow of molten glass Gm provided in the lower part of the main body 31. It includes an outlet 33 and a tubular inflow portion 34.

The inflow port 32 is provided on the upper side wall of the main body 31. On the other hand, the outlet 33 is provided at the lower end of the main body 31, but is not limited to this. The outflow port 33 may be below the inflow port 32, and may be provided on the lower side wall of the main body 31, for example.

An inflow portion 34 extending in the lateral direction is connected to the inflow port 32. A connecting pipe 9 is connected to the upstream end of the inflow portion 34. That is, the molten glass Gm is transferred from the previous process (in this embodiment, the stirring tank 5) into the main body 31 through the inflow section 34.

The outflow port 33 is inserted into the inside of the connecting pipe 10 through the opening 10a of the connecting pipe 10 as an outflow portion. The outlet 33 is immersed in the molten glass Gm inside the connecting pipe 10. That is, the molten glass Gm in the main body 31 is transferred to the next step (molding apparatus 3 in this embodiment) through the connecting pipe 10.

The main body 31 has a large diameter portion 31a provided with the inflow port 32 in the upper portion and a small diameter portion 31b provided with the outflow port 33 in the lower portion. The large diameter portion 31a and the small diameter portion 31b are, for example, cylindrical bodies. The inner diameter of the large diameter portion 31a is preferably 1.5 to 5 times the inner diameter of the small diameter portion 31b, for example. The main body 31 may be provided between the large diameter portion 31a and the small diameter portion 31b with a reduced diameter portion (for example, a conical shape) whose diameter is gradually reduced from the upper side to the lower side. Alternatively, the main body 31 may be a single tubular body having a constant inner diameter.

The state adjusting tank 6 includes a first electrode 35, a second electrode 36, and a third electrode 37 in this order from the upstream side to the downstream side in the transfer direction of the molten glass Gm.

The first electrode 35 is provided at the inflow portion 34 (in the illustrated example, the upstream end of the inflow portion 34).

The second electrode 36 and the third electrode 37 are provided on the main body 31.

Specifically, although the second electrode 36 is provided in the large diameter portion 31a, it is preferable that the second electrode 36 is provided above the inflow port 32 (in the illustrated example, the upper end of the large diameter portion 31a). In other words, the second electrode 36 is preferably located above the liquid level Gs of the molten glass Gm in the main body 31. As a result, devitrification of the molten glass Gm near the liquid level Gs can be suppressed.

Although the third electrode 37 is provided in the large diameter portion 31a, it is preferable that the third electrode 37 is provided below the inflow port 32 (in the illustrated example, the lower end of the large diameter portion 31a). The third electrode 37 may be provided in the small diameter portion 31b (for example, near the lower end of the small diameter portion 31b).

Between the first electrode 35 and the second electrode 36, there is a first current supply path 38 for energizing the first portion (inflow portion 34) of the state adjusting tank 6 located between the electrodes 35 and 36. It is provided. The first current supply path 38 is provided with a first power supply 39 for applying a voltage between the first electrode 35 and the second electrode 36. By applying a voltage from the first power supply 39, the first alternating current i1 is supplied to the inflow portion 34.

Between the second electrode 36 and the second electrode 37, a second current supply path 40 for energizing the second portion (large diameter portion 31a) of the state adjusting tank 6 located between the electrodes 36 and 37. Is provided. The second current supply path 40 is provided with a second power supply 41 that applies a voltage between the second electrode 36 and the third electrode 37. By applying a voltage from the second power supply 41, the second alternating current i2 is supplied to the large diameter portion 31a. The second electrode 26 is a common electrode used in both the first current supply path 38 and the second current supply path 40.

The state adjusting tank 6 is provided with a phase adjusting unit 42 for adjusting the phase difference θ between the first alternating current i1 and the second alternating current i2. The phase adjusting unit 42 is connected to the first power supply 39 and the second power supply 41. The first power supply 39, the second power supply 41, and the phase adjusting unit 42 are composed of, for example, a three-phase AC power supply.

The phase adjusting unit 42 sets the maximum value of the first alternating current i1 to A, the maximum value of the second alternating current i2 to B, and supplies the first alternating current i1 and the second alternating current i2 to the second electrode 36. When the maximum value of the alternating current i3 is C, the third alternating current i3 of the first alternating current i1 and the second alternating current i2 so as to satisfy the relationship of the above equation (1) or (4). It is configured to adjust the phase difference θ. That is, in the method for manufacturing a glass article, the third alternating current i3 satisfies the relationship of the above formula (1) or (4) in the transfer step (in this embodiment, the state adjusting step included in the transfer step). As described above, the phase difference θ between the first alternating current i1 and the second alternating current i2 is adjusted.

By adjusting the phase difference θ between the first alternating current i1 and the second alternating current i2 in this way, the magnitude of the third alternating current i3 flowing through the second electrode 36 can be easily and surely adjusted. Then, if the phase difference θ between the first alternating current i1 and the second alternating current i2 is adjusted so that the third alternating current i3 satisfies the relationship of the above equation (1) or (4), the second electrode The upper portion of the large-diameter portion 31a provided with the 36 is efficiently heated. Therefore, the temperature near the liquid level Gs of the molten glass Gm located above the large diameter portion 31a becomes high. That is, in the vicinity of the liquid level Gs of the molten glass Gm, a glass stagnation layer and devitrification are generally likely to occur, which can be suppressed.

Here, the liquid level Gs of the molten glass Gm of the main body 31 is between the upper end and the lower end of the inflow port 32 of the main body 31 as shown in FIG. 4 from the viewpoint of preventing the glass stagnant layer and devitrification. It is preferably located in. The height of the liquid level Gs of the molten glass Gm is, for example, the inflow amount and / or the outflow of the molten glass Gm as the heating temperature (viscosity of the molten glass Gm) due to energization of the molten glass Gm is increased or decreased. This can be achieved by changing the amount.

The present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-mentioned effects. The present invention can be modified in various ways without departing from the gist of the present invention.

In the above embodiment, the case where the stirring tank or the state adjusting tank is energized and heated by using the first electrode, the second electrode and the third electrode has been described, but the energizing heating method according to the present invention is the stirring tank and the state. It may be applied to both adjustments at the same time. Further, the energization heating method according to the present invention can be similarly applied to other parts of the transfer device.

In the above embodiment, the case where the glass article molded by the molding apparatus is flat glass has been described, but the present invention is not limited to this. The glass article molded by the molding apparatus may be, for example, a glass roll obtained by winding a glass film into a roll, an optical glass component, a glass tube, a glass block, a glass fiber, or any other shape. good.

Hereinafter, examples according to the present invention will be described, but the present invention is not limited to these examples.

In this embodiment, in the stirring tank 5 shown in FIG. 3, the phase difference θ1 between the first alternating current i1 and the second alternating current i2 and the phase difference θ2 between the first alternating current i1 and the fourth alternating current i4 are changed. The changes in the third alternating current i3 and its maximum value C when the current is made are shown. The maximum value A of the first alternating current i1 was 3000A, the maximum value B of the second alternating current i2 was 2000A, and the maximum value D of the fourth alternating current i4 was 500A. The third alternating current i3 and its maximum value C at this time can be obtained from the above equations (6) and (7). The results are shown in FIG. 6 and Table 1.

From FIG. 5 and Table 1, if the phase difference θ1 between the first alternating current i1 and the second alternating current i2 and the phase difference θ2 between the first alternating current i1 and the fourth alternating current i4 are not properly managed, Comparative Examples 1 to 1 It can be seen that the maximum value C of the third alternating current i3 becomes very small as in No. 2, and the second electrode 12 and its surroundings cannot be efficiently heated. On the other hand, if the phase difference θ1 between the first alternating current i1 and the second alternating current i2 and the phase difference θ2 between the first alternating current i1 and the fourth alternating current i4 are appropriately managed, as in the first to third embodiments. It can be seen that the maximum value C of the third alternating current i1 becomes large, and the second electrode 12 and its surroundings can be efficiently heated. Here, in Examples 1 and 2, the maximum value C of the third alternating current i1 satisfies the relationship of the above equation (5), and in the third embodiment, the maximum value C of the third alternating current i1 is the above equation ( The relationship of 8) is satisfied.

1 Melting furnace 2 Transfer device 3 Molding device 4 Clarification tank 5 Stirring tank 6 Condition adjustment tank 11 Main body 12 Inflow part 13 Outflow part 17 Discharge part 18 1st electrode 19 2nd electrode 20 3rd electrode 21 1st current supply path 22 1st power supply 23 2nd current supply path 24 2nd power supply 25 Phase adjustment unit 26 4th electrode 27 3rd current supply path 28 3rd power supply 31 Main body 34 Inflow part 35 1st electrode 36 2nd electrode 37 3rd electrode 38 1st current supply path 39 1st power supply 40 2nd current supply path 41 2nd power supply 42 Phase adjustment unit G Glass ribbon Gm Molten glass i1 1st AC current i2 2nd AC current i3 3rd AC current i4 4th AC current

Claims (7)

A method for manufacturing a glass article including a transfer step of transferring molten glass using a transfer device.
The transfer device includes a first electrode, a second electrode, and a third electrode which are sequentially provided from the upstream side to the downstream side along the transfer path of the transfer device.
In the transfer step, a first alternating current is supplied to the first portion of the transfer device located between the first electrode and the second electrode.
A second alternating current is supplied to the second part of the transfer device located between the second electrode and the third electrode.
When the maximum value of the first alternating current is A, the maximum value of the second alternating current is B, and the maximum value of the third alternating current flowing through the second electrode by supplying current to the transfer device is C. ,
The third alternating current is
(A ² + B ² + AB) ^1/2 ≤ C
A method for manufacturing a glass article, which comprises adjusting the phase difference between the first alternating current and the second alternating current so as to satisfy the above relationship. When the maximum value of the first alternating current is A, the maximum value of the second alternating current is B, and the maximum value of the third alternating current is C,
The third alternating current is
A + B = C
The method for manufacturing a glass article according to claim 1, wherein the phase difference between the first alternating current and the second alternating current is adjusted so as to satisfy the above relationship. The transfer device includes a stirring tank.
The stirring tank includes a bottomed main body extending in the vertical direction and an outflow portion provided on the lower side wall of the main body for transferring the molten glass in the main body to the next step.
The first electrode is provided on the main body portion above the outlet of the main body portion to which the outflow portion is connected.
The second electrode is provided on the main body below the outlet.
The method for manufacturing a glass article according to claim 1 or 2, wherein the third electrode is provided in the outflow portion. The stirring tank further includes a discharge portion provided at the bottom of the main body portion for discharging the molten glass in the main body portion, and a fourth electrode provided at the discharge portion.
The method for manufacturing a glass article according to claim 3, wherein in the transfer step, a fourth alternating current is supplied to the discharge portion located between the second electrode and the fourth electrode. When the maximum value of the first alternating current is A, the maximum value of the second alternating current is B, the maximum value of the third alternating current is C, and the maximum value of the fourth alternating current is D.
The third alternating current is
(A ² + B ² + D ² + AB + AD + 2BD) ^1/2 ≤ C
The method for manufacturing a glass article according to claim 4, wherein the phase difference between the first alternating current, the second alternating current, and the fourth alternating current is adjusted so as to satisfy the above relationship. The transfer device includes a state adjustment tank.
The state adjusting tank includes a main body portion having a bottom extending in the vertical direction and an inflow portion provided on a side wall of an upper portion of the main body portion.
The first electrode is provided in the inflow portion and is provided.
The second electrode is provided on the main body portion above the inflow port of the main body portion to which the inflow portion is connected.
The method for manufacturing a glass article according to claim 1 or 2, wherein the third electrode is below the inflow port and is provided on the main body. A device for manufacturing glass articles provided with a transfer device for transferring molten glass.
The first electrode, the second electrode, and the third electrode, which are sequentially provided from the upstream side to the downstream side along the transfer path of the transfer device,
A first power source that supplies a first alternating current to the first portion of the transfer device located between the first electrode and the second electrode.
A second power source that supplies a second alternating current to the second portion of the transfer device located between the second electrode and the third electrode.
When the maximum value of the first AC current is A, the maximum value of the second AC current is B, and the maximum value of the third AC current flowing through the second electrode due to the current supply to the transfer device is C.
The third alternating current is
(A ² + B ² + AB) ^1/2 ≤ C
A glass article manufacturing apparatus comprising a phase adjusting unit for adjusting a phase difference between the first alternating current and the second alternating current so as to satisfy the above relationship.

Images