KR20230008058A - Method for manufacturing a glass article and apparatus for manufacturing a glass article - Google Patents

Abstract

It is a manufacturing method of a glass article provided with the conveyance process which uses the conveyance device 2 and conveys molten glass Gm. The stirring tank 5 included in the transfer device 2 is a body portion 11 with a bottom extending in the vertical direction and a body portion in order to transfer the molten glass Gm in the body portion 11 to the next step ( 11), an outflow portion 13 formed at the bottom of the side wall, a discharge portion 14 formed at the bottom of the body portion 11 to discharge the molten glass Gm in the body portion 11, and the body portion ( 11) and a first electrode 18 installed at the bottom and a second electrode 19 installed at the discharge part 14. In the transfer step, the discharge portion 14 is heated by supplying electricity between the first electrode 18 and the second electrode 19 .

Description

Method for manufacturing a glass article and apparatus for manufacturing a glass article

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

A method for producing a glass article includes a conveying step of conveying molten glass produced in a melting furnace to a forming device using a conveying device, and a forming step of forming a glass article such as sheet glass from the molten glass using a forming device ( For example, see Patent Literature 1).

The conveying device is provided with a plurality of electrodes at intervals in order from the upstream side to the downstream side along the conveying path, and molten glass transported inside the conveying device is heated by energizing between these electrodes (for example, , see Patent Documents 2 and 3). In addition, a clarification tank, a stirring tank, a condition adjustment tank (pot) etc. are contained in a conveyance apparatus, for example.

Japanese Unexamined Patent Publication No. 2016-88754 Japanese Unexamined Patent Publication No. 2012-101970 Japanese Unexamined Patent Publication No. 2012-116693

By the way, the stirring tank or the like included in the transfer device is provided with a bottomed main body extending in the vertical direction, and an outflow portion formed at the lower part of the side wall of the main body in order to transfer the molten glass in the main body to the next process.

In the case of such a configuration, the fluidity of the molten glass around the bottom of the main body is insufficient, and a glass stagnant layer tends to occur around the bottom of the main body. This glass stagnant layer may contain heterogeneous glass of a composition different from that of the molten glass that normally flows inside the body portion. When such heterogeneous glass is mixed in the normally flowing molten glass, it may become a defect in the glass article to be manufactured. Therefore, from the viewpoint of manufacturing a high-quality glass product, it is desired to suppress the generation of a glass stagnant layer around the bottom of the body portion.

An object of the present invention is to suppress the generation of a glass stagnant layer around the bottom of a bottomed main body portion extending in the vertical direction.

The present invention invented to solve the above problems is a method for manufacturing a glass article comprising a conveying step of conveying molten glass using a conveying device, wherein the conveying device includes a body portion with a bottom extending in the vertical direction, and a main body portion. An outflow part formed on the lower part of the side wall of the body part to transfer the molten glass inside the body to the next process, a discharge part formed on the bottom part of the body part to discharge the molten glass in the body part, a first electrode installed on the bottom part, , and a second electrode installed in the discharge portion, and in the transfer process, the discharge portion is heated by applying current between the first electrode and the second electrode.

In this case, the temperature of the molten glass around the bottom of the body portion rises due to the heating of the discharge portion. As a result, the fluidity of the molten glass around the bottom of the main body is improved, and generation of a glass stagnant layer around the bottom of the main body can be suppressed.

In the above configuration, it is preferable that the transfer device further includes a third electrode provided on the main body portion upstream of the first electrode, and in the transfer step, the first electrode and the third electrode are energized to heat the main body portion.

In this way, the molten glass inside the body portion can be adjusted to a suitable temperature by heating the body portion.

In the above configuration, A is the maximum value of the first AC current supplied to the discharge unit, B is the maximum value of the second AC current supplied to the body unit, and the third current is supplied to the transfer device and flows to the first electrode. When the maximum value of the AC current is C, the phase difference between the first AC current and the second AC current is adjusted so that the third AC current satisfies the relationship of (A ² +B ² +AB) ^1/2 ≤ C. desirable.

By adjusting the phase difference between the first AC current and the second AC current in this way, the first electrode (common electrode) used both when supplying the first AC current to the discharge unit and when supplying the second AC current to the body unit It is possible to simply and reliably increase the magnitude of the third alternating current flowing through. And, if the phase difference between the first and second AC currents is adjusted so that the third AC current satisfies the relationship of the above equation, the third AC current flowing through the first electrode increases, and the efficiency of molten glass around the first electrode increases. It can heat up nicely. Therefore, generation|occurrence|production of the glass stagnant layer in the periphery of the bottom part of a body part can be suppressed more reliably.

In the above structure, it is preferable that the glass transport device further includes a fourth electrode provided in the outlet portion, and in the transfer step, the outlet portion is heated by supplying electricity between the first electrode and the fourth electrode.

In this way, the molten glass inside the outlet can be adjusted to a suitable temperature by heating the outlet.

In the above configuration, A is the maximum value of the first AC current supplied to the discharge unit, B is the maximum value of the second AC current supplied to the body unit, and the third current is supplied to the transfer device and flows to the first electrode. If the maximum value of the AC current is C and the maximum value of the fourth AC current supplied to the outlet is D, the third AC current is (A ² +B ² +D ² +AB+2AD+BD) ^1/2 It is preferable to adjust the phase difference of the first AC current, the second AC current, and the fourth AC current so as to satisfy the relationship ?C.

By adjusting the phase difference of the first AC current, the second AC current, and the fourth AC current in this way, when the first AC current is supplied to the outlet, the second AC current is supplied to the main body, and the fourth AC to the outlet. The magnitude of the third alternating current flowing through the first electrode (common electrode), which is used both when supplying current, can be increased simply and reliably. When the phase difference of the first AC current, the second AC current, and the fourth AC current is adjusted so that the third AC current satisfies the relationship of the above equation, the third AC current flowing through the first electrode increases, and the surrounding area of the first electrode increases. molten glass can be efficiently heated. Therefore, generation|occurrence|production of the glass stagnant layer in the periphery of the bottom part of a body part can be suppressed more reliably.

In the above configuration, it is preferable that the transfer device includes a stirring tank having a main body discharge portion and an outlet portion.

The present invention, devised to solve the above problems, is an apparatus for manufacturing a glass article having a conveying device for conveying molten glass, wherein the conveying device includes a main body portion with a bottom extending in the vertical direction, and the molten glass in the main body portion as follows. An outflow portion formed at the bottom of the side wall of the body portion for transporting to the process, a discharge portion formed at the bottom portion of the body portion for discharging molten glass in the body portion, a first electrode installed at the bottom portion, and a discharge portion installed at the discharge portion. It is characterized in that it includes a second electrode and a power source for supplying current to a discharge unit located between the first electrode and the second electrode.

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

ADVANTAGE OF THE INVENTION According to this invention, generation|occurrence|production of the glass stagnant layer in the periphery of the bottom part of a body part can be suppressed.

1 is a side view showing an apparatus for manufacturing a glass article according to a first embodiment of the present invention.
Fig. 2 is a cross-sectional view showing the periphery of the stirring tank of the glass article manufacturing apparatus according to the first embodiment of the present invention.
Fig. 3 is a cross-sectional view showing the periphery of the stirring tank of the glass article manufacturing apparatus according to the second embodiment of the present invention.
Fig. 4 is a cross-sectional view showing the periphery of the stirring tank of the glass article manufacturing apparatus according to the third embodiment of the present invention.
5 is a graph showing changes in a third AC current according to an embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described with reference to an accompanying drawing. Note that, in each embodiment, the same reference numerals are assigned to corresponding components, so that overlapping descriptions are omitted in some cases. In the case where only a part of the configuration is described in each embodiment, the configuration of the other embodiment previously described can be applied to other parts of the configuration. In addition, 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 not specified unless there is a problem with the combination.

(1st Embodiment)

As shown in Fig. 1, in the first embodiment, a glass product manufacturing apparatus and a glass product manufacturing method are exemplified. The glass product manufacturing apparatus according to the present embodiment includes a melting furnace 1, a conveying apparatus 2, and a molding apparatus 3 in order from the upstream side to the downstream side in the conveying direction of the molten glass Gm. In addition, the method for manufacturing a glass product according to the present embodiment includes a melting step, a transfer step, and a molding step in this order. In addition, the manufacturing method of a glass article is demonstrated together when explaining the structure of the manufacturing apparatus of a glass article.

The melting furnace 1 is for performing the melting process of continuously forming molten glass Gm. As a method of heating the molten glass Gm (or glass raw material) in the melting furnace 1, for example, a method of heating only by energization heating (total pre-melting method), a method of heating only by combustion of gas fuel, energization heating and gas It is possible to adopt a method of heating by using combustion of fuel together.

In this embodiment, molten glass Gm consists of alkali-free glass. The alkali-free glass is a glass composition, for example, 50 to 70% of SiO ₂ , 12 to 25% of Al ₂ O ₃ , 0 to 12% of B ₂ O ₃ , Li ₂ O + Na ₂ O + K ₂ O in terms of mass%. (the sum of Li ₂ 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 alkali-free glass is generally high, for example, 100 Ω·cm or more at a heating temperature of the melting furnace 1 of 1500°C.

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 conveying device 2 is for carrying out a conveying process of conveying the molten glass Gm from the melting furnace 1 toward the molding device 3, and the conveying path (space) for conveying the molten glass Gm is provided inside. It consists of a transfer pipe with Here, the term conveying pipe includes those having a tubular structure as well as those having a tubular (container shape) structure.

In this embodiment, the transfer device 2 is equipped with the clarification tank 4, the stirring tank 5, the condition adjustment tank (port) 6, and the connection pipes 7-10 which connect these each part. . That is, the transfer process includes a clarification process, a stirring process, and a condition adjustment process.

The clarification tank 4 is for performing the clarification process which clarifies (defoaming) the molten glass Gm supplied from the melting furnace 1 by the action of a clarifier etc.

The stirring tank 5 is for performing the homogenization process which stirs and homogenizes the molten glass Gm clarified by the clarification tank 4 with the stirring blade (stirr) 5a.

The conditioning tank 6 is for performing a conditioning process of adjusting the molten glass Gm stirred in the stirring tank 5 to a state suitable for molding. The condition adjusting tank 6 is a tank without mechanical agitation means such as stirring blades, and is located on the most downstream side when the conveying device 2 has a plurality of tanks as described above. In other words, the conditioning tank 6 is a tank that adjusts the flow rate, viscosity, and the like of the molten glass Gm just before the molding device 3 .

The connecting pipes 7 to 10 are configured of, for example, a cylindrical body made of platinum or a platinum alloy (for example, a cylindrical body), and transport the molten glass Gm in the transverse direction (substantially horizontal direction) . In this embodiment, among the conveying device 2, the connection pipe 7 located in the uppermost part, and the connection pipe 9 which connects the stirring tank 5 and the conditioning tank 6, the downstream side is higher than the upstream side. It is inclined to be located at .

The molding device 3 is for performing a molding process of molding the molten glass Gm transported by the conveying device 2 into a desired shape. In this embodiment, the shaping|molding apparatus 3 is provided with the molded object which continuously molds glass ribbon G from molten glass Gm by the overflow down-draw method.

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

In the case of the overflow down-draw method, the molten glass Gm supplied to the forming device 3 overflows from the groove formed at the top of the forming device 3 to form a wedge shape in cross section of the forming device 3. By joining at the lower end along both sides forming the plate-shaped glass ribbon (G) is continuously formed. After the molded glass ribbon G is slowly cooled (annealed) and cooled, it is cut into a predetermined size, and sheet glass as a glass article is manufactured.

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

As shown in FIG. 2 , the stirring vessel 5 includes a body portion 11, an inlet portion 12, an outlet portion 13, and an outlet portion 14.

The body portion 11 is a cylindrical body with a bottom extending along the vertical direction, and equipped with stirring blades 5a therein. By rotating this stirring blade 5a about an axis|shaft, it is comprised so that stirring of the molten glass Gm in the main-body part 11 is possible.

The body portion 11 includes an inlet 15 formed on the upper side wall, an outlet 16 formed on the lower side wall, and an outlet 17 formed on the bottom.

Connected to the inlet 15 is a tubular inlet 12 extending in the lateral direction. A connection pipe 8 is connected to the end of the inlet portion 12 on the upstream side. That is, molten glass Gm is conveyed into the body part 11 from the previous process (the clarification tank 4 in this embodiment) through the inflow part 12.

To the outlet 16 is connected a tubular outlet 13 extending in the lateral direction. A connection pipe 9 is connected to the downstream end of the outflow portion 13 . That is, the molten glass Gm in the body part 11 is transferred to the next process (conditioning tank 6 in this embodiment) through the outflow part 13.

Connected to the outlet 17 is a tubular outlet (drain) 14 extending in the vertical direction. During manufacture of the glass product, the discharge portion 14 is blocked by the solidified glass Gx solidified within the discharge portion 14 . On the other hand, when the molten glass (Gm) is discharged, the solidified glass (Gx) in the discharge part 14 is heated to soften and flow so that the molten glass (Gm) in the body part 11 is discharged to the outside through the discharge part 14. do.

A first electrode 18 is installed on the bottom (lower end) of the body portion 11, and a second electrode 19 is installed on the lower end of the discharge portion 14. The position of the second electrode 19 may be any position of the discharge section 14 as long as it is lower than the first electrode 18 . However, it is preferable to install the second electrode 19 at the lower end of the discharge part 14 from the viewpoint of expanding the heating area by energizing the discharge part 14 .

Each of the electrodes 18 and 19 is made of, for example, a ring-shaped flange portion made of platinum or a platinum alloy, and is joined to the outer circumferential surface of the stirring vessel 5 by welding or the like at a predetermined position. Although not shown, each of the electrodes 18 and 19 is a lead electrode (for example, made of platinum or a platinum alloy) for connecting a current supply path 20 described later, or a cooling mechanism (for example, water cooling). ) is further provided.

A first current supply path 20 is formed between the first electrode 18 and the second electrode 19 to conduct electricity to the discharge portion 14 located between the electrodes 18 and 19 . A first power source (voltage source) 21 for applying a voltage between the first electrode 18 and the second electrode 19 is installed in the first current supply path 20 . A first alternating current i1 is supplied to the discharge unit 14 by applying a voltage from the first power source 21 .

In this case, the temperature of the molten glass Gm around the bottom of the body portion 11 rises due to energization heating of the discharge portion 14 . As a result, the fluidity of the molten glass Gm around the bottom of the body portion 11 is improved, and generation of a glass stagnant layer around the bottom of the body portion 11 can be suppressed.

In addition, the energization heating of the ejection part 14 at the time of manufacturing such a glass article is such that the solidified glass Gx in the ejection part 14 does not soften and flow, that is, the molten glass Gm from the ejection part 14 to the extent that it does not spill out. For example, what is necessary is just to energize heating so that the temperature of the hardened glass Gx of the discharge part 14 may become below a softening point. On the other hand, when discharging the molten glass Gm in the body portion 11 to the outside through the discharge portion 14, the first alternating current i1 supplied by the first power source 21 is more than at the time of manufacturing the glass product. It is enlarged, and the solidified glass (Gx) of the discharge part 14 is softened and fluidized.

(Second Embodiment)

As shown in FIG. 3, the modified example of the stirring tank 5 is illustrated in 2nd Embodiment. In addition, since the basic structure of the stirring vessel 5 is the same as that of 1st Embodiment, a difference with 1st Embodiment is mainly demonstrated.

In this embodiment, the 3rd electrode 22 is provided in the upper end part of the body part 11. In addition, the position of the 3rd electrode 22 may be any position of the body part 11, as long as it is on the upstream side of the 1st electrode 18. However, from the viewpoint of expanding the heating region by energization of the body portion 11, the position of the third electrode 22 is preferably above the liquid level Gs of the molten glass Gm in the body portion 11, , It is more preferable that it is the upper end of the main body part 11.

A second current supply path 23 is formed between the first electrode 18 and the third electrode 22 to conduct electricity to the main body 11 located between the electrodes 18 and 22 . A second power supply (voltage source) 24 for applying a voltage between the first electrode 18 and the third electrode 22 is installed in the second current supply path 23 . The second alternating current i2 is supplied to the main body 11 by applying a voltage from the second power source 24 . Also, the first electrode 18 is a common electrode used in both the first current supply path 20 and the second current supply path 23 .

If it does in this way, the molten glass Gm in the main body part 11 can be adjusted to suitable temperature by electric heating of the main body part 11. Therefore, even when the magnitude of the first alternating current i1 supplied to the discharge section 14 by the first power source 21 is reduced, the generation of a glass stagnant layer around the bottom of the main body section 11 is reliably suppressed. can do.

Moreover, in this embodiment, the phase adjustment part 25 which adjusts the phase difference (theta) of the 1st alternating current i1 and the 2nd alternating current i2 is provided in the stirring tank 5. The phase adjusting unit 25 is connected to a first power supply 21 and a second power supply 24 . The 1st power supply 21, the 2nd power supply 24, and the phase adjustment part 25 are comprised by 3-phase AC power supply, for example. 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 terminal (eg, TR, RT, RS, SR, etc.) there is.

For example, the phase adjusting unit 25 sets the maximum value of the first AC current i1 as A, the maximum value of the second AC current i2 as B, the first AC current i1 and the second AC current i2 When the maximum value of the third AC current i3 flowing through the first electrode 18 by supply of ) is C, the third AC current i3 satisfies the relationship of Equation (1) below: It is configured to adjust the phase difference θ of the alternating current i1 and the second alternating current i2. That is, in the glass article manufacturing method, in the conveying step (the stirring step included in the conveying step in this embodiment), the first alternating current ( i1) and the phase difference θ of the second alternating current i2 are adjusted.

(A ² +B ² +AB) ^1/2 ≤C...(1)

Here, i1=Asin(ωt+θ), i2=Bsinωt, and i3=i2−i1 are defined. Also, ω is the angular velocity, t is time, and θ is the phase difference of the first AC current i1 with respect to the second AC current i2. The phase difference θ is based on the phase of the second AC current i2, but is not limited thereto. Since the direction of each current is defined in FIG. 3, when the part to which the first electrode 18 is attached (junction with the main body 11) is regarded as a branch point, the flow-in current to the branch point is i2, and the outflow from the branch point is Since the currents are i1 and i3, the third alternating current i3 is represented by "i2-i1" as described above from 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=Bsinωt-Asin(ωt+θ)

=(B-Acosθ)sinωt-Asinθcosωt...(2)

In addition, Equation (2) can be expressed as the following Equation (2)' from the synthesis formula of trigonometric functions.

i3={(B-Acosθ) ² +A ² sin ² θ} ^1/2 sin(ωt-α)

=(A ² +B ² -2ABcosθ) ^1/2 sin(ωt-α) ... (2)'

Here, sinα=Asinθ/(A ² +B ² -2ABcosθ) ^1/2 , and cosα=(B−Acosθ)/(A ² +B ² -2ABcosθ) ^1/2 .

Since -1≤sin(ωt-α)≤1, 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 AC current i1 and the second AC current i2 in this way, the magnitude of the third AC current i3 flowing through the first electrode 18 can be easily and reliably adjusted. there is. Then, if the phase difference θ between the first AC current i1 and the second AC current i2 is adjusted so that the third AC current i3 satisfies the relationship of Equation (1) above, the first electrode 18 The third alternating current (i3) flowing through is large, and the periphery of the first electrode 18 or the bottom of the main body 11 can be efficiently heated. For this reason, the flow of the molten glass Gm around the bottom part of the body part 11 becomes favorable. That is, generation of the glass stagnant layer around the bottom of the body portion 11 can be suppressed more reliably.

The phase adjusting unit 25 is preferably configured to adjust the phase difference θ between the first AC current i1 and the second AC current i2 so as to satisfy the relationship of Equation (4) below.

A+B=C...(4)

Here, the phase difference θ is preferably 120° to 240° (or -120° to -240°), more preferably 180° (or -180°). In addition, the left side of equation (1) is the value of equation (3) when θ = 120 ° (or -120 °), and the left side of equation (4) is the value when θ = 180 ° (or -180 °) It is the value of formula (3).

The maximum value A of the first AC current i1 and the maximum value B of the second AC current i2 may be the same, but are preferably different values (for example, B>A). In addition, at least one of the maximum value A of the first AC current i1 and the maximum value B of the second AC current i2 together with the phase difference θ so as to satisfy the relationship of Equation (1) or (4) above. may be adjusted

(Third Embodiment)

As shown in FIG. 4, the modified example of the stirring vessel 5 is illustrated in 3rd Embodiment. In addition, since the basic structure of the stirring tank 5 is the same as that of 2nd Embodiment, a different point from 2nd Embodiment is mainly demonstrated.

In this embodiment, the fourth electrode 26 is provided in the outflow part 13 (the downstream end of the outflow part 13 in the illustration).

A third current supply path 27 is formed between the first electrode 18 and the fourth electrode 26 to conduct electricity to the outlet 13 located between the electrodes 18 and 26 . A third power supply (voltage source) 28 for applying a voltage between the first electrode 18 and the fourth electrode 26 is provided in the third current supply path 27 . A fourth alternating current i4 is supplied to the outlet 13 by applying a voltage from the third power supply 28 . Also, the first electrode 18 is a common electrode used in all of the first current supply path 20, the second current supply path 23, and the third current supply path 27.

If it does in this way, the molten glass Gm in the outlet part 13 can be adjusted to suitable temperature by electric heating of the outlet part 13. Therefore, even when the magnitude of the first alternating current i1 supplied to the discharge section 14 by the first power source 21 is reduced, the generation of a glass stagnant layer around the bottom of the main body section 11 is reliably suppressed. can do.

In the present embodiment, the phase adjusting unit 25 is connected to the first power supply 21, the second power supply 24, and the third power supply 28, and the first AC current i1 and the second AC current i2 ) and the phase difference θ2 of the second AC current i2 and the fourth AC current i4 are adjusted. The 1st power supply 21, the 2nd power supply 24, the 3rd power supply 28, and the phase adjustment part 25 are comprised by 3-phase AC power supply, for example.

For example, the phase adjusting unit 25 sets the maximum value of the first AC current i1 to A, the maximum value of the second AC current i2 to B, the maximum value of the third AC current i3 to C, and the second AC current i3 to C. 4 When the maximum value of the AC current i4 is D, the ratio of the first AC current i1 and the second AC current i2 is such that the third AC current i3 satisfies the relationship of Equation (5) below. It is configured to adjust the phase difference θ1 and the phase difference θ2 of the second AC current i2 and the fourth AC current i4. That is, in the method of manufacturing a glass article, in the conveying step (the stirring step included in the conveying step in the present embodiment), the first alternating current ( The phase difference θ1 between i1) and the second AC current i2 and the phase difference θ2 between the second AC current i2 and the fourth AC current i4 are adjusted.

(A ² +B ² +D ² +AB+2AD+BD) ^1/2 ≤ C... (5)

Here, i1=Asin(ωt+θ1), i2=Bsinωt, i4=Dsin(ωt+θ2), and i3=i2-i1-i4 are defined. In addition, ω is the angular velocity, t is time, θ1 is the phase difference of the first AC current i1 with respect to the second AC current i2, and θ2 is the difference between the fourth AC current i4 and the second AC current i2. It is a phase difference. The phase differences θ1 and θ2 are based on the phase of the second AC current i2, but are not limited thereto. The third AC current i3 is a current flowing through the first electrode 18 by supplying the first AC current i1, the second AC current i2, and the fourth AC current i4.

In this case, the third alternating current i3 can be expressed by the following formula (6) from the addition theorem of trigonometric functions.

i3=Bsinωt-Asin(ωt+θ1)-Dsin(ωt+θ2)

=(B-Acosθ1-Dcosθ2)sinωt

-(Asinθ1+Dsinθ2)cosωt...(6)

In addition, Equation (6) can be expressed as the following Equation (6)' from the synthesis formula of trigonometric functions.

i3={(B-Acosθ1-Dcosθ2) ²

+(Asinθ1+Dsinθ2) ² } ^1/2 sin(ωt-α) ... (6)'

However, if r = {(B-Acosθ1-Dcosθ2) ² + (Asinθ1 + Dsinθ2) ² } ^1/2 , sinα = (Asinθ1 + Dsinθ2)/r and cosα = (B-Acosθ1-Dcosθ2)/r .

Since -1≤sin(ωt-α)≤1, 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={(B-Acosθ1-Dcosθ2) ²

+(Asinθ1+Dsinθ2) ² } ^1/2 ... (7)

By adjusting the phase difference (θ1, θ2) between the first AC current (i1), the second AC current (i2), and the fourth AC current (i4), the third AC current (i3) flowing through the first electrode 18 ) can be resized simply and reliably. And, the phase difference θ1 between the first AC current i1, the second AC current i2, and the fourth AC current i4 so that the third AC current i3 satisfies the relationship of Equation (5) above. When θ2) is adjusted, the third alternating current i3 flowing through the first electrode 18 increases, and the area around the bottom of the first electrode 18 or the main body 11 can be efficiently heated. For this reason, it is possible to more reliably suppress the formation of a glass stagnant layer around the bottom of the main body portion 11 .

The phase adjusting unit 25 adjusts the phase differences θ1 and θ2 between the first AC current i1, the second AC current i2, and the fourth AC current i4 so as to satisfy the relationship of Equation (8) below. It is desirable that it is configured to do so.

A+B+D=C...(8)

Here, the phase difference θ1 and θ2 is preferably 120°≤θ≤240° (or -120°≥θ≥-240°), more preferably 180° (or -180°). The left side of equation (5) is the value of equation (7) when θ1 = θ2 = 120° (or -120°), and the left side of equation (8) is θ1 = θ2 = 180° (or -180°) ) is the value of Formula (7) when

The maximum value A of the first AC current i1, the maximum value B of the second AC current i2, and the maximum value D of the fourth AC current i4 may be the same, but are preferably different values (for example, , B>D>A). In addition, the maximum value A of the first AC current (i1), the maximum value B of the second AC current (i2) and At least one of the maximum values D of the 4 alternating currents i4 may be adjusted.

The present invention is not limited to the configuration of the above embodiment, nor is it limited to the above-described effects. Various changes are possible in the present invention without departing from the gist of the present invention.

The energization heating method described in the above embodiment can also be applied to a stirring vessel connecting a plurality of body parts. In this case, it is preferable to connect the upper part of one of the adjacent two body parts and the lower part of the other with a connection pipe.

In the above embodiment, an electrode may be further provided in the inlet part of the stirring vessel, and electricity may be further supplied between the electrode in the inlet part and the third electrode in the main body part. This promotes heating of the inlet section or the upper end of the main body section.

The energization heating method described in the above embodiment can be similarly applied to parts other than the stirring tank in the conveying device.

In the above embodiment, the case where the glass article to be molded with the molding device is plate glass has been described, but it 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 in a roll shape, an optical glass component, a glass tube, a glass block, a glass fiber, or the like, or may have an arbitrary shape.

Example

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 vessel 5 shown in FIG. 4, the phase difference θ1 between the first AC current i1 and the second AC current i2, the second AC current i2 and the fourth AC current ( Changes in the third alternating current i3 and its maximum value C when the phase difference θ2 of i4) is changed are respectively shown. Further, the maximum value A of the first AC current i1 was 500 A, the maximum value B of the second AC current i2 was 3000 A, and the maximum value D of the fourth AC current i4 was 2000 A. The third alternating current i3 and its maximum value C at this time are obtained from the above equations (6) and (7). The results are shown in Fig. 5 and Table 1.

5 and Table 1, the phase difference θ1 between the first AC current i1 and the second AC current i2 and the phase difference θ2 between the second AC current i2 and the fourth AC current i4 are appropriately set. If not managed, it is understood that the maximum value C of the third alternating current i3 becomes small, and the heating efficiency of the first electrode 18 and its surroundings decreases, as in Examples 4 to 5. On the other hand, if the phase difference θ1 between the first AC current i1 and the second AC current i2 and the phase difference θ2 between the second AC current i2 and the fourth AC current i4 are properly managed, the embodiment As in 1 to 3, it is understood that the maximum value C of the third alternating current i1 is increased, and the first electrode 18 and its surroundings can be efficiently heated. Here, in Examples 1 and 2, the maximum value C of the third AC current i1 satisfies the relationship of Equation (5), and in Example 3, the maximum value C of the third AC current i1 It satisfies the relationship of Equation (8).

1 melting furnace 2 transfer device
3 Forming device 4 Clarification tank
5 Agitation bath 6 Conditioning bath
11 body part 12 inlet part
13 Outlet 14 Outlet
18 first electrode 19 second electrode
20 First current supply path 21 First power source
22 Third electrode 23 Second current supply path
24 2nd power supply 25 phase adjustment unit
26 Fourth electrode 27 Third current supply path
28 Third Power G Glass Ribbon
Gm molten glass i1 1st alternating current
i2 2nd AC current i3 3rd AC current
i4 4th alternating current

Claims (7)

A method for producing a glass article comprising a conveying step of conveying molten glass using a conveying device, comprising:
The conveying device includes a main body portion having a bottom extending in the vertical direction, an outflow portion formed at a lower portion of a side wall of the main body portion to transfer the molten glass in the main body portion to a next process, and the molten glass in the main body portion. In order to discharge the discharge portion formed on the bottom of the body portion, a first electrode installed on the bottom portion, and a second electrode installed on the discharge portion,
The method for manufacturing a glass article according to claim 1 , wherein in the conveying step, an electric current is applied between the first electrode and the second electrode to heat the discharge portion. According to claim 1,
The transfer device further includes a third electrode provided in the body portion on an upstream side of the first electrode,
The manufacturing method of the glass article which heats the main body part by applying electricity between the said 1st electrode and the said 3rd electrode in the said transfer process. According to claim 2,
The maximum value of the first AC current supplied to the discharge unit is A, the maximum value of the second AC current supplied to the body unit is B, and the third AC flowing to the first electrode by current supply to the transfer device When the maximum value of the current is C, the third alternating current,
(A ² +B ² +AB) ^1/2 ≤C
A method for manufacturing a glass article comprising adjusting a phase difference between the first alternating current and the second alternating current so as to satisfy the relationship of . According to claim 2,
The glass conveying device further includes a fourth electrode installed in the outlet part,
The manufacturing method of the glass article which heats the said outflow part by applying electricity between the said 1st electrode and the said 4th electrode in the said transfer process. According to claim 4,
The maximum value of the first AC current supplied to the discharge unit is A, the maximum value of the second AC current supplied to the body unit is B, and the third AC flowing to the first electrode by current supply to the transfer device When the maximum value of the current is C and the maximum value of the fourth alternating current supplied to the outlet is D,
The third alternating current,
(A ² +B ² +D ² +AB+2AD+BD) ^1/2 ≤C
A method for manufacturing a glass article comprising adjusting the phase difference of the first AC current, the second AC current, and the fourth AC current so as to satisfy the relationship of . According to any one of claims 1 to 5,
The manufacturing method of a glass article in which the said conveying device is provided with the stirring tank which has the said main body part, the said discharge part, and the said outlet part. An apparatus for manufacturing a glass article having a conveying device for conveying molten glass, comprising:
The conveying device is
A body portion having a bottom extending in the vertical direction;
an outflow portion formed at a lower portion of a side wall of the body portion to transfer the molten glass in the body portion to a next process;
a discharge portion formed at the bottom of the body portion for discharging the molten glass in the body portion;
A first electrode installed on the bottom;
A second electrode installed in the discharge part;
and a power source for supplying current to the discharge unit located between the first electrode and the second electrode.

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