TWI633072B - Apparatus and method for making glass - Google Patents

Abstract

A molten glass transfer apparatus is disclosed that includes a clarification vessel including a wall, wherein the thickness of the clarification vessel wall changes circumferentially. In some embodiments, the upper portion of the clarification container that contacts the gas atmosphere within the clarification container is thinner than the remaining portion of the clarification container that contacts the molten glass. A method for clarifying molten glass is also disclosed.

Description

Apparatus and method for manufacturing glass 【priority】

This application claims the priority right of US Provisional Application No. 61/892624 filed on October 18, 2013 in accordance with the provisions of the Patent Law. This article relies on the content of this case and the entire contents of this case are incorporated herein by reference.

This disclosure relates generally to equipment for manufacturing glass, and more specifically to molten glass transfer equipment that includes a container including a wall having a thickness that varies circumferentially with the perimeter of the container.

Melting raw materials to form a molten material (hereinafter referred to as molten glass) requires the use of combustion gases and / or electrical energy during the melting process. The raw material can then be conditioned and transferred from the melting furnace to the forming equipment. In some processes, molten glass is transferred to a forming facility via a precious metal transfer facility that includes various processing equipment. To ensure controlled temperature, certain components of the transfer device can be heated directly by generating electrical current in the components. The current heats the component, which in turn heats the molten glass in the component. Different components of the transmission equipment have different energy requirements. The component in the conveying equipment with perhaps the highest power requirements is a clarification vessel, in which the molten glass is adjusted to remove gases caused by the melting process.

To enable the removal of air bubbles after the melting process and to ensure that any solid particles leaking from the melting furnace are dissolved, the clarification vessel is kept at an extremely high temperature. Bubbles rise faster at lower viscosity, and solid inclusions dissolve faster at higher temperatures. There is an air gap at the top of the clarifier. Unfortunately, oxidation of precious metals (eg, platinum and / or rhodium) can occur in the presence of oxygen, and the rate at which oxidation occurs increases with temperature and oxygen content. Oxidation of precious metals results in thinning of the metal. Oxidation is usually more severe at the top of the clarification vessel for at least two reasons: 1) there is an air gap above the surface of the molten glass; and 2) the temperature is highest at the top of the clarification vessel. The temperature at the top of some glass clear containers can exceed 1700 ° C. Generally, the temperature at the top of the clarification vessel may be on average 20 ° C higher than the temperature of the molten glass contained in the lower part of the clarification vessel. Because higher temperatures at the top of the clarification vessel can cause corrosion cracking of the clarification vessel, it is necessary to lower the temperature of the clarification vessel top.

The fusion glass manufacturing process can produce thin glass sheets with special surface qualities, making these glass sheets ideal for manufacturing visual display products such as televisions, mobile phones, computer monitors, and the like. In a typical fusion process, raw materials (called batches) are melted in a refractory ceramic melting furnace to produce molten glass. The molten glass is then transferred to the forming body via a transfer device. The forming body includes a groove formed in an upper surface of the forming body; and an outer tapered forming surface. The molten glass is received by the groove from the transfer device, where the molten glass flows out and flows down as a separate stream from the tapered forming surface. The separate streams meet where the tapered shaped surfaces meet to form a single glass ribbon that is cut into individual glass pieces once cooled to an elastic solid.

Although the melting furnace and the forming body are mainly composed of a refractory ceramic material, the conveying equipment that conveys the molten glass to the forming body usually uses a high-temperature metal, and in particular, an oxidation-resistant high-temperature metal. Suitable metals can be selected, for example, from the platinum group metals, that is, platinum iridium, rhodium, palladium, osmium, and ruthenium. Alloys of the aforementioned platinum group metals can also be used. For example, since it is easier to physically manufacture than other platinum group metals, molten glass transfer equipment is typically constructed of platinum or a platinum alloy, such as a platinum-rhodium alloy.

When the molten glass is transferred via a conveying device, the molten glass may be conditioned by passing the molten glass through a conditioning container, such as a clarification container, in which a degassing process occurs. Various gases are released during the melting process. If left in the molten glass, these gases can create bubbles in the final glass object, such as a glass sheet from a fusion process. In order to eliminate bubbles from the glass, the temperature of the molten glass is raised in the clarification vessel to a temperature greater than the melting temperature. The polyvalent compounds included in the batch and present in the molten glass release oxygen during the temperature increase, and help remove gases formed during the melting process from the molten glass. The gas is released into the exhaust space of the clarification vessel above the free surface of the molten glass. In some cases, for example, in the production of glass sheets for the display industry, the temperature in the clarification container may exceed 1650 ° C and even more than 1700 ° C, and is close to the melting temperature of the clarification container wall.

One way to increase the temperature in a clarification vessel is to create an electric current in the clarification vessel, where the temperature increases through the resistance of the metal walls of the vessel. This direct heating may be referred to as Joule heating. To achieve this, electrodes (also known as flanges) are attached to the clarification vessel and serve as the inlet and outlet positions for the electrical current.

Monitor the temperature of the clarification container at various locations on the clarification container. It is implemented by embedding a thermocouple in a refractory insulating material which surrounds the clarification container. The data from this monitoring show the elevated temperature of the clarification vessel, where the gas atmosphere above the free surface of the molten glass contacts the clarification vessel wall. This is due to the lowered thermal conductivity of the gas atmosphere in the clarification container relative to the thermal conductivity of the molten glass contained in the lower part of the clarification container. The profiling performed on the deactivated clarification vessel showed excessive oxidation in the portion of the clarification vessel above the non-contacting molten glass (especially where the flange was bonded to the clarification vessel wall). This oxidation occurs due to the high temperature of the metal in the presence of oxygen. Unfortunately, it is difficult to completely eliminate oxygen from the environment surrounding the container. In addition, oxidation gradually thins the metal of the container wall (the molten glass does not flow through the container wall) in the container area, resulting in eventual cracking of the container wall. Therefore, the embodiments disclosed herein are directed to controlling the current flow through the wall of the clarification container to reduce the temperature of the other part of the wall, which part contacts the gas atmosphere in the clarification container and the molten glass does not flow through this part.

In one aspect, a molten glass transfer device is disclosed, the device comprising: a clarification vessel configured as a tube, the tube including a wall, the tube wall including a metal, the metal being selected from the group consisting of: platinum , Rhodium, palladium, iridium, ruthenium, osmium and the alloys of each of them; and a plurality of flanges that surround the tube and are arranged to direct current through the wall, the plurality of flanges comprising , Palladium, iridium, ruthenium, osmium, and alloys of the above. At least a portion of the wall between at least two consecutive flanges of the plurality of flanges includes a thickness that changes circumferentially. The phrase "two consecutive flanges" is intended to indicate that in the direction of flow of the molten glass, the molten glass passes through two consecutive flanges in sequence, with no intermediate flange between the two consecutive flanges.

At least a portion of the wall may include a first wall portion and a second wall portion, and a thickness of the first wall portion may be smaller than a thickness of the second wall portion in a cross-section of at least a portion of the wall. The thickness of the first wall portion may be substantially uniform, and the thickness of the second wall portion may be substantially uniform. The first wall portion is positioned at the top of the clarification container, and the second wall portion is positioned at the bottom of the clarification container, below the first wall portion.

The molten glass transfer apparatus may further include a third wall portion positioned between the first wall portion and the second wall portion. The thickness of the third wall portion in the cross section may be greater than the thickness of the second wall portion.

The second wall portion may be configured to include a plurality of layers. For example, the second wall portion may include a laminated structure including a plurality of metal plates.

In another embodiment, at least a portion of the wall of the clarification container may include a first wall portion and a second wall portion, wherein the thickness of the first wall portion is greater than the thickness of the second wall portion. The first wall portion is positioned at the top of the clarification container, and at least a portion of the wall can be positioned adjacent one of the two continuous flanges.

The thickness of the first wall portion and / or the second wall portion may be substantially uniform.

In some embodiments, when the first wall portion is thicker than the second wall portion, the length of the first wall portion may be no greater than about 16 cm.

When the first wall portion is thicker than the second wall portion, the first wall portion may include a plurality of metal layers. According to some aspects of this embodiment, the first wall portion abuts one of two consecutive flanges. In other aspects, the flange may be attached to an upper surface of the first wall portion, such as a center portion of the first wall portion, such that the first wall portion extends outward from a flange parallel to the longitudinal axis of the clarification container . In a In one example, the first wall portion has a length of 16 cm along the longitudinal axis of the clarification container, and the flange is attached to the first portion at a midpoint of the length of 16 cm. It should be apparent from the foregoing that the length may be different from 16 cm, for example, less than 16 cm, and the flange is attached to the first wall portion at a midpoint of the length of the first wall portion.

At least a portion of the wall may include a first length portion; a second length portion; and a third length portion, the third length portion being remote from the first length portion, the first length portion being positioned between the third length portion and the second length portion between. The thickness of the first length portion may be changed circumferentially, the thickness of the second length portion may be changed circumferentially, and the thickness of the third length portion may be substantially constant. In addition, each of the first length portion and the second length portion may include a first wall portion and a second wall portion, and a thickness of the first wall portion of the first length portion and the second length portion is greater than the first length portion. And the thickness of the second wall portion of the second length portion. The first length portion and the first wall portion of the second length portion are positioned at the top of the clarification container.

Each of the first and second length portions may be positioned adjacent to one of the two consecutive flanges such that each of the first and second length portions abuts the two consecutive flanges. Respective flanges.

The molten glass transfer apparatus may further include a fourth length portion positioned between adjacent flanges, the fourth length portion includes the first wall portion and the second wall portion, and the first wall portion of the fourth length portion is positioned At the top of the clarification container. The thickness of the first wall portion of the fourth length portion may be greater than the thickness of the second wall portion of the fourth length portion.

In yet another embodiment, a method of forming glass is disclosed, the method comprising the steps of: melting a batch in a melting furnace; and self-melting the molten glass The furnace flows through a metal clarification vessel such that the molten glass contains a free surface within the clarification vessel and the atmosphere is positioned between the clarification vessel and the free surface, the clarification vessel contains a wall that includes a first wall portion and A first thickness; and a second wall portion that includes a second thickness such that the first thickness is different from the second thickness in a cross section. The molten glass flow can then be controlled so that the molten glass flow does not flow out of the surface of the upper wall portion. Therefore, the first wall portion is positioned at the top of the clarification container and the second wall portion is positioned at the bottom of the clarification container.

The first thickness may be smaller than the second thickness, or the first thickness may be larger than the second thickness.

In some embodiments, the clarification container may include a third wall portion positioned between the first wall portion and the second wall portion, and the third wall portion includes a third thickness. In cross section, the first The three thicknesses are greater than the first thickness and the second thickness. The level of molten glass in the clarification vessel can be controlled so that the free surface intersects the third wall portion.

The temperature of the first wall portion may be, for example, at least 5 degrees Celsius (° C) lower than the temperature of the second wall portion.

Additional features and advantages of the present disclosure will be explained in the detailed description that follows, and for those skilled in the art, the additional features and advantages will be partially obvious from their descriptions or by practicing this article (including the detailed description that follows) , Patent application scope, and accompanying drawings).

It should be understood that both the foregoing general description and the following detailed description present embodiments of the disclosure and are intended to provide an overview or framework for understanding the nature and characteristics of the claimed embodiments. Includes accompanying drawings to provide insight into this disclosure One step understanding, and accompanying drawings are incorporated into this specification and form part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the description serve to explain the principles and operations of the embodiments.

10‧‧‧ Glass forming equipment

12‧‧‧ arrow

14‧‧‧melting furnace

16‧‧‧ molten glass

18‧‧‧ connecting catheter

20‧‧‧ clarification container

22‧‧‧ stirred container

24‧‧‧ Connect the catheter

26‧‧‧ Connect the catheter

28‧‧‧ transport container

30‧‧‧outlet catheter

32‧‧‧ entrance duct

34‧‧‧formed body

36‧‧‧ tapered surface

38‧‧‧ root

40‧‧‧glass ribbon

42‧‧‧ flange

43‧‧‧ at least part

44‧‧‧ Outer wall

44a‧‧‧First wall section

44b‧‧‧Second wall section

44c‧‧‧ Third wall section

44a ₁ ‧‧‧ first length

44a ₂ ‧‧‧ second length

44a ₃ ‧‧‧ third length

46‧‧‧plane

48‧‧‧ vertical axis

49‧‧‧ electrode

50‧‧‧ free surface

52‧‧‧Gas atmosphere

54‧‧‧Inner surface

56‧‧‧ outer surface

58‧‧‧area

60‧‧‧arrow

64‧‧‧ Busbar

66‧‧‧ Busbar

70‧‧‧ curve

72‧‧‧ curve

74‧‧‧ curve

75‧‧‧thickness band

76‧‧‧ curve

78‧‧‧ curve

80‧‧‧ curve

82‧‧‧ curve

84‧‧‧ curve

86‧‧‧ curve

88‧‧‧ curve

90‧‧‧ curve

E‧‧‧ potential

I _a ‧‧‧ current

I _b ‧‧‧ current

L‧‧‧ length

RE _a ‧‧‧first resistance element

RE _b ‧‧‧Second resistance element

RE _a1 ‧‧‧ the first resistance element section

RE _a2 ‧‧‧Second resistance element section

T ₁ ‧‧‧ first temperature

T ₂ ‧‧‧Second temperature

t‧‧‧thickness

t _a ‧‧‧ wall thickness

t _a1 ‧‧‧ thickness

t _a2 ‧‧‧ thickness

t _a3 ‧‧‧ thickness

t _b ‧‧‧ wall thickness

t _c ‧‧‧ thickness

Za‧‧‧High current density area

Zb‧‧‧ molten glass area

θ‧‧‧ angle

Φ‧‧‧corner

FIG. 1 is a front view of an exemplary fusion pull-down glass manufacturing apparatus according to an embodiment described herein, the apparatus including a clarification container; FIG. 2 is a perspective view of the clarification container of FIG. 1; and FIG. 3 is a view of the prior art A cross-sectional view of a clarification container including a wall having a uniform thickness on the circumference; FIG. 4 is a photograph of corrosion cracking of the wall of the clarification container; and FIG. 5 is a cross-sectional view of the clarification container according to the embodiment described herein Where the thickness of the clarification vessel wall changes circumferentially; Figure 6 is an electrical schematic diagram illustrating the effects described in Figure 5; Figure 7 is a cross-sectional view of another clarification vessel according to the embodiment described herein, where The thickness of the clarification container wall changes circumferentially so that the upper wall portion is thinner than the lower wall portion and the lower wall portion contains layers; FIG. 8 is a cross-sectional view of another clarification container according to an embodiment described herein, in which the clarification The thickness of the container wall changes circumferentially, and the intermediate wall portion is positioned between the upper and lower wall portions; Figure 9 is a side view of the clarification container, which contains clarification Both the thin part and the thick part in the upper part of the device; Figure 10 is a cross-sectional view of the clarified container of Figure 9, where the cross-section is taken at the thick part of the upper wall part; Figure 11 is Figure 9 Cross-sectional view of a clarification container, in which The section is taken at the thin part of the upper wall part; Figure 12 is an electrical schematic diagram illustrating the effects of both the thin upper wall part and the thick upper wall part in the clarification container; Figure 13 is a side view of the clarification container, The clarification container includes a thin upper wall portion positioned between two thick upper wall portions; FIG. 14 is a side view of the clarification container, which illustrates the upper wall portion, the lower wall portion, and the upper wall portion and the lower wall portion. Between two continuous flanges, where the upper wall portion is thinner than the lower wall portion, and the electrode attached to the flange extends upward from near the top of the clarification container; FIG. 15 is a view of the clarification container according to the embodiment A cross section in which the flange electrode extends upward from the position closest to the top of the flange on the flange; FIG. 16 is a cross section of the clarification container according to the embodiment, where the flange electrode is closest to the bottom of the flange on the flange Extending downward; Figure 17 is a modeled and actual temperature change along the length of the clarification container. The clarification container has a wall, and the thickness of the wall is substantially circumferentially uniform at the cross section of the clarification container, and Figure The temperature at the top of the clarification container, which is usually higher than the temperature at other parts of the clarification container; Figure 18 is a side view of the clarification container modeled by the curve of Figure 17; Figure 19 is the modeled current density A graph showing the variation of the length of the clarification container along Figures 17 and 18; Figure 20 is a graph illustrating the variation of the modeled temperature with the length of the clarification container. The clarification container includes an upper wall portion and a lower wall portion And the thickness of the upper wall portion is smaller than the thickness of the lower wall portion; and FIG. 21 is a graph illustrating the variation of the modeled current density with the length of the clarification container of FIG. 20.

As used herein, the singular forms "a" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, unless the context clearly dictates otherwise, references to "flange" include aspects having two or more such flanges.

Ranges may be expressed herein as "about" one particular value and / or to "about" another particular value. When expressing this range, another aspect includes from one particular value and / or to another particular value. Similarly, when a value is expressed as an approximation by using the aforementioned word "about", it will be understood that a particular value forms another aspect. It will be further understood that the endpoint of each of the ranges is clearly related to and independent of the other endpoint. When a range is expressed as being "between" one value and another value, one value and the other value indicate the endpoints of the range and are included in the range.

As used herein, unless specifically stated, the terms "having" and "including" are open-ended and do not exclude the presence of other properties, characteristics, attributes, or elements.

As used herein, the term "circumferential" is generally interpreted as being about the angular position around the perimeter of the cross-section and is not limited to a circular cross-section, and thus the wording where the thickness changes circumferentially means an article (e.g., a clarifying container) The thickness of the cross-section of the wall varies with the angular position of the clarification container relative to the longitudinal axis and is not limited to circular (cylindrical) clarification containers.

As used herein, an angle enclosed by an arc, line, or other curve is the angle at which two rays pass through the endpoints of the arc.

As used herein, the term "container" should be construed to include grooves, conduits, tubes, or other structures into which molten glass may be contained or flow.

In the exemplary glass forming apparatus 10 of FIG. 1, a batch indicated by an arrow 12 is melted in a melting furnace 14 to form a molten glass 16 at a first temperature T ₁ . T ₁ depends on the specific glass composition, but for glass suitable for use as a substrate for a liquid crystal display, T ₁ may exceed 1500 ° C. The molten glass flows from the melting furnace 14 through the connection duct 18 to the clarification vessel 20. The glass flows from the clarification container 20 through the connection conduit 24 to the stirring container 22, where the molten glass is mixed and homogenized, and from the stirring container 22 through the connection conduit 26 to the transfer container 28, and thereafter through the outlet conduit 30 to Inlet conduit 32 of the shaped body. The molten glass can then be guided from the inlet conduit 32 to the shaped body 34. In the case of the fusion pull-down process as shown in Fig. 1, the molten glass conveyed to the forming body 34 flows out of the tapered forming surface 36, where the individual flows meet at a position where the tapered forming surface meets (called the root portion 38). Together or fused to form a glass ribbon 40. The tape can then be cooled and separated to form individual glass sheets.

At fining vessel 20, the molten glass heated to a second temperature T _2, T ₂ which is higher than T _1. Heating of the clarification vessel 20 may be accomplished, for example, by establishing an electric potential on at least a portion of the length of the clarification vessel via a flange 42 coupled to the clarification vessel. The flange 42 is in turn connected to a suitable power source (not shown). The clarification container 20 includes at least two flanges 42. The electric potential is responsible for generating an electric current, which heats the clarification vessel. An additional flange may also be connected to the connection duct 18 for similarly directly heating the connection duct to heat the molten glass flowing through the connection duct to a clearing temperature T ₂ . However, T ₁ up to 1500 ℃, and in some cases even higher, T ₂ than T ₁ is at least 100 ℃. The relatively high temperature T ₂ reduces the viscosity of the molten glass, thereby allowing the bubbles in the molten material to be more easily eliminated from the molten glass. In addition, higher temperatures release oxygen contained in the fining agent (e.g., a polyvalent oxide material), which enters the molten glass via the batch. The released oxygen forms bubbles in the molten glass, and these bubbles can be used as nucleation sites for other gases. That is, the dissolved gas in the molten glass migrates into the oxygen bubbles, thereby increasing the bubbles. The increased buoyancy caused by bubble growth accelerates the removal of bubbles from the molten glass via the free surface of the molten glass. In addition, when the bubbles rise from the molten glass, a certain local mechanical agitation of the glass also occurs, which further stimulates gas extraction.

Although the melting furnace 14 typically contains a refractory ceramic material (e.g., a tile or a large monolithic ceramic block), many of the downstream transfer equipment responsible for transferring molten glass from the melting furnace to the forming body is typically formed of a conductive metal. These components include a connection conduit 18, a connection conduit 24, a connection conduit 26, a clarification container 20, a stirring container 22, a transfer container 28, an outlet conduit 30, and an inlet 32.

As mentioned above, the molten glass is at an elevated temperature, and as a result, conveyor equipment components require "high temperature" materials (eg, materials capable of withstanding temperatures in excess of at least 1500 ° C for extended periods of time). In addition, the material should be resistant to oxidation, which is accelerated by high temperatures in the presence of oxygen. In addition, the molten glass can be quite corrosive, so the material is more resistant to the impact of the molten glass, which can cause the resulting glass objects to be contaminated by the container material. Metals containing platinum group metals of the periodic table (i.e., platinum, rhodium, iridium, palladium, ruthenium, osmium, and alloys of the above) are particularly suitable for this purpose, and because platinum can be more easily handled than other platinum group metals, Many high temperature processes use platinum or platinum alloy containers. One One commonly used platinum alloy is platinum-rhodium alloy. However, because the precious metals are expensive, efforts are being made to minimize the size of the containers to reduce the weight of the metals used.

In order to extract the maximum amount of gas from the molten glass in the clarification vessel, the molten glass is raised to the clarification temperature T ₂ . Heating of the molten glass may begin within the connecting conduit 18 between the melting furnace 14 and the clarification vessel 20 so that the molten glass is at or near the clarification temperature when entering the clarification vessel. Although indirect heating via a heating coil outside the connecting conduit 18 can be utilized, heating can be done more efficiently by the direct heating method previously outlined. For directly heated clarification vessels, the current can be alternating current (AC) or direct current (DC). Both direct connection heating and the clarification vessel may be utilized, and thus both the connection conduit and the clarification vessel may include a flange 42.

To ensure a substantially uniform current flow through the clarification vessel, attention needs to be paid to the design of the flange 42 and the attachment of the flange 42 to the clarification vessel. However, hot spots in the clarification vessel wall have been monitored in the part above the clarification vessel wall.

Figure 2 illustrates a perspective view of at least a portion 43 of a clarification container 20 having a nominal cylindrical cross-sectional shape and length L, and including a number of flanges 42 which are shown attached to and The electrical contact clarification vessel is illustrated in Figure 2 as at least a portion of the endpoint. As used herein, unless otherwise specified, the term "cross-sectional shape" or more simply "cross-section" refers to the shape of the outer wall 44 of the clarification container cut by a plane 46 that is perpendicular to the longitudinal axis 48 of the clarification container. Although the following description assumes a cylindrical cross-sectional shape, it should be understood that other geometric cross-sectional shapes may be utilized, such as an elliptical shape, an oval shape, or an "orbital" (e.g., oblong) shape that includes a curved Two relatively flat wall portions connected by a wall portion, wherein the shape is The dimension in one direction (e.g., width) is greater than the height of the shape in the orthogonal direction (e.g., height). The electrode 49 electrically contacts the flange 42 and is used to connect the flange to a power source via a cable, bus bar, or other electrical conductor.

Figure 3 illustrates an exemplary clarification container in cross section, the clarification container including a longitudinally closed wall 44 that closes a longitudinally extending space in the clarification container. The cross section of the figure 3 contains molten glass 16 which has a free surface 50 which contacts the gas atmosphere 52 above the free surface. The wall 44 includes an inner surface 54 and an outer surface 56, wherein the inner surface 54 faces the inner space of the clarification container enclosed by the wall, and the outer surface 56 is exposed to the surrounding environment outside the clarification container. More specifically, FIG. 3 illustrates the relative thickness of the wall 44 around the circumference of the clarification container, which wall 44 extends between the inner surface and the outer surface, and the thickness is substantially constant in the clarification container illustrated. That is, the thickness “t” of the cross section of the clarification container wall shown in FIG. 3 at any angular position around the circumference of the clarification container is substantially the same, only within the normal manufacturing tolerance and at the joint and / Or changes in welding points.

In order to reduce the heat loss of the clarification container 20, the clarification container may be surrounded by one or more layers of refractory insulation material (not shown), and the thermocouple embedded in this refractory sheath can be used to monitor the clarification container at and near the thermocouple location. temperature. As mentioned earlier, this monitoring illustrates the elevated temperature of the container wall at the location where the inner surface 54 of the wall contacts the contained gas atmosphere 52, and where the non-wall portion contacts the molten glass. The profiling performed on the deactivated clarification vessel showed increased oxidative corrosion of the metal in the portion of the clarification vessel where the inner surface 54 did not contact the molten glass flowing through the clarification vessel. This local corrosion thins the wall prematurely. Wall thinning can increase the current density in other parts of the wall, which can further increase the temperature degree. Therefore, once wall thinning begins, corrosion (eg, oxidation) can become an instability process that proceeds faster and faster until the clarification vessel wall is cracked and the clarification vessel must be taken out of use. The corrosion cracked photo is shown in Figure 4, where the area 58 shown includes a clarification of the wall of the container. In addition, cracks from corrosion can extend around the clarification container, and in extreme cases, the cracks can meet and completely separate one part of the clarification container from the other.

It should be understood that the etching process described above is usually a local event and depends at least on the local current density and oxygen concentration. That is, the corrosion does not occur uniformly over the entire wall surface, even when it is considered that only the other part of the container wall contacts the gas atmosphere above the free surface of the molten glass. Also, since it may be difficult to control the oxygen concentration on a local basis, one direction is to control the current density, and therefore the temperature of the clarification vessel wall.

Therefore, the clarification container 20 according to the embodiments described herein is configured to have a cross-sectional shape such that the wall thickness changes circumferentially around the clarification container in at least a portion of the clarification container, and in some embodiments, the wall thickness may vary with The entire length of the clarification container is changed. That is, when examining the cross-section of the clarification container, the thickness of the clarification container wall may change angularly as the cross-section is viewed around the circumference of the cross-section. In other embodiments, the wall thickness may be changed in one cross-section of the clarification vessel and not changed in the other cross-section. FIG. 5 illustrates a cross-section of a clarification container 20 according to an embodiment, wherein the clarification container includes an upper or first wall portion 44a that forms a first arc; and a lower or second wall portion 44b, the lower or second wall portion 44b forms a second arc, wherein the first wall portion and the second wall portion include the entire clarification container wall 44. Each of the first wall portion and the second wall portion includes a wall thickness t _a and a wall thickness t _b , respectively, and according to the present embodiment, when the clarification container is viewed in a cross section, t _{b is} greater than t _a . That is, the wall thickness t _{a of the} upper wall portion 44 a in the cross section is smaller than the wall thickness t _{b of the} lower or second wall portion 44 _b in the cross section. As shown in FIG. 5, the free surface 50 of the molten glass 16 intersects the second wall portion 44 b so that the molten glass 16 does not flow out of the upper wall portion 44 a of the clarification container 20. The angle θ surrounded by the first arc of the upper wall portion may range from about 10 degrees to about 180 degrees, and therefore, in some embodiments, the upper wall portion may include the entire upper half of the clarification container, or in other In an embodiment, only a portion of the upper half of the container is included. The range of the complementary angle Φ surrounded by the second arc of the lower or second wall portion may be about 180 degrees to about 350 degrees.

In the embodiment of FIG. 5, the thicker lower second wall portion 44b may exhibit a reduced resistance to the current of the clarification vessel compared to the resistance of the upper portion. Therefore, when compared to the current in the second wall portion, the lower current in the first wall portion may produce a reduced temperature in the first wall portion. This situation can be better understood with the help of Figure 6.

FIG. 6 illustrates an electrical schematic diagram of the first resistance element RE _a and the second resistance element RE _b . The resistive element RE _a includes a length L _a , a cross-sectional area A _a, and a resistivity ρ _a . The resistance element RE _b includes a length L _b , a cross-sectional area A _b, and a resistivity ρ _b . Each resistive element can be imagined, for example, as a cylindrical, solid and homogeneous wire. As shown in FIG. 6, the resistance element RE _a and the resistance element RE _b are connected in parallel between the two bus bars 64 and 66, and a potential E is imposed between the two bus bars. In this example, RE _a may be used to indicate the upper wall portion 44 a of the clarification container 20, and resistance element RE _b may be used to indicate the lower wall portion 44 _{b of the} clarification container 20. Both of which are assumed to the same resistor element, so that the _{L a = L b, A a} = A b and ρ _a = ρ _b, both having the same resistive element are resistors, i.e. the resistance of the resistance element RE _a R _a Is equal to the resistance R _b of the resistive element RE _b (wherein generally the resistivity ρ is equal to the resistance R times the area A divided by the length L). Thus, through the RE _a current I _a is equal to the current through the RE _b I _b (ignoring other transmission loss). The total current I _t of both the resistive element RE _a and the resistive element RE _b is I _a + I _b or E / (R _a R _b / (R _a + R _b )). The values are inserted, assuming that E is 10 volts and that R _a and R _b are each 5 ohms. Then I _a and I _b are each 2 amps, and the total current I _t is I _a + I _b = 4 amps. The total power P (assuming 100% effective conversion) as heat consumption is P = I _t E. Insert the above values, P = 10 Volts × 4 Amps = 40 Watts.

The foregoing example assumes that the resistance element RE _{a is the} same as the resistance element RE _b . It is now assumed that the cross-sectional area of the resistive element RE _a is reduced such that A _a <A _b , with all other conditions equal to the previous example. That is, it is assumed that the resistance element RE _a is the same wire as in the foregoing example, and the only difference is that it is thinner. This is equivalent to reducing the thickness of the upper wall portion 44a, for example. Then in this example, R _a > R _b and I _a <I _b . Using the values of the preceding example, it is assumed that the resistance element RE _a resistance R _a is now 6 ohms, and the resistance of the resistance element RE _b R _b is 5 ohms. Now I _a is 10 volts / 6 ohms = 1.67 amps, and I _b = 10 volts / 5 ohms = 2 amps. I _total becomes 3.67 amps, and P = 10 volts × 3.67 amps = 36.7 watts, thereby illustrating the reduced power. In the foregoing example, RE _a and RE _b may be used to indicate the upper portion 44 a and the lower portion 44 _{b of the} clarification vessel wall, respectively. Therefore, the reduced power entering the glass from the clarification vessel entering the glass may result in a reduced total glass temperature. However, it is not ideal to cool the glass to a temperature that is less than the initial basic situation, because the same process conditions will be maintained for the molten glass. Therefore, in order to keep the total temperature of the molten glass the same as the basic case, the power entering the molten glass should be kept constant. In this case, for example, the power E can be increased to about 10.44 volts by increasing the voltage E on the bus bar to obtain 40 again. Watt power. At 10.44 volts, I _a is now about 1.74 amps and I _b is about 2.089 amps. Thus, even for the same power of the basic case, a first resistance element RE _a current I _a in the case of reduction with respect to the base, and a second resistive element of the current RE _b I _b increases.

The foregoing simple example illustrates the thickness of the upper wall portion of the clarification container 20 (that is, the portion of the clarification container wall that contacts the gas atmosphere above the free surface of the molten glass) relative to the lower wall portion (that is, the clarification container wall The thinner part that touches the molten glass can reduce the current in the upper wall part of the clarification vessel, and thus also lower the temperature of the upper wall part. A reduction in temperature of even a few degrees Celsius can lead to a significant extension of the useful life of the clarification container. Because the increase in current in the lower part is distributed in a much larger cross-sectional area (the lower part is much larger and thicker than the upper part), the increase in current in the lower part can have only a negligible effect (only in the current density Can be slightly increased).

It should be noted that the foregoing description via the circuit diagram is at least too simple for clarifying the reasons that the upper wall portion and the lower wall portion of the container are not separate components but are continuously combined. Electrical analysis is much more complicated for physical clarification vessels. However, computer analysis using Fluent® calculation software has confirmed the effect obtained. Therefore, the foregoing description is useful for understanding the basic principles.

In some embodiments, for example, the thickness of the upper or first wall portion 44a may be made smaller than the thickness of the lower wall portion by laminating the lower or second wall portion 44b with additional material as shown in FIG. For example, in the case where the manufacture of the lower wall portion includes rolling a metal plate into a cylindrical plate of any thickness, a second metal plate of any thickness may be rolled into a second cylindrical plate and such as It is bonded to the first plate by welding, so that the thickness of the first plate is increased by at least the thickness of the second plate. The second layer may be the same material as the first layer or a different material. Adding one or more layers can increase the overall cost of the clarification vessel due to the need to use additional materials (in the case of platinum group metals, this situation can be significant). On the other hand, the amount by which the thickness of the upper portion can be reduced is limited by enabling the clarification container structure to maintain the shape of the clarification container structure at a temperature very close to the melting point of the metal during an extended period of time, or to increase the lower portion The thickness is mainly limited by cost. Therefore, the increase in the useful life of the clarification container can exceed the initially increased cost.

In another embodiment shown in FIG. 8, the clarification container 20 may further include a third wall portion 44c, which is positioned between the first wall portion 44a and the second wall portion 44b. Third wall portion 44c comprises _b is greater than the third thickness t of t _c. Since the thickness t _{c of the} third wall portion 44 _{c is} greater than the thickness of the wall thicknesses t _a and / or t _b , cracks (such as those caused by thinning based on oxidation) that may be formed in the first wall portion 44 a may be Propagation to the lower or second wall portion 44b of the clarification container is prevented by the increased thickness of the wall portion 44c. As shown in FIG. 8, the level of the molten glass in the clarification container 20 may be controlled so that the free surface 50 of the molten glass 16 intersects the second wall portion 44 b and, in some embodiments, may intersect the third wall Section 44c intersects. Methods to control the level of molten glass in glass manufacturing systems are known and are not discussed further herein.

An analysis of the decommissioned clarification vessel also illustrates that the oxidative corrosion of the clarification vessel is generally more likely to begin at or near the location where the flange is bonded to or the first wall portion 44a, for example, where the flange 42 intersects the upper wall portion 44a Around 16 Within centimeters (cm). Therefore, in yet another embodiment shown in FIG. 9, the upper wall portion 44a of the clarification container 20 may be partially thickened relative to another portion of the upper or first wall portion 44a.

FIG. 9 illustrates the clarification container 20 and a partially thickened portion of the upper wall portion 44 a adjacent to the flange 42. The increased thickness of the short (partial) portion along the longitudinal axis of the clarification container of the lower or first wall portion 44a relative to the upper or second wall portion 44b can reduce the current density in a portion of the upper wall portion of the clarification container. This case can be particularly effective when the local thickening of the upper wall portion 44 a is located at a position adjacent to the flange 42. Thus, two consecutive flanges 42 between the upper wall portion 44a may include a first length portion and a second length portion _{44a. 1} 44a _2, 44a ₂ wherein the second length portion 42 is positioned adjacent to and abuts the flange, and wherein the second The thickness t _{a2 of the} upper wall portion of the length portion 44a ₂ is larger than the thickness t _{a1 of the} upper wall portion of the first length portion 44a ₁ , as shown in the cross sections of FIGS. 10 and 11. Continuous flange means that there are no additional flanges between the target flanges. According to the present embodiment, the second wall portion 44b can comprise a thickness that is equal to or greater than the first thickness of the first length portion 44 _a1 of the upper wall or portion (i.e., t _b t _a1 ). The second wall portion 44b may further include a thickness that is equal to or greater than the thickness of the second wall portion 44a ₂ or the first wall portion (t _b t _a2 ). The following additional simple diagram shown in Figure 12 will help to understand the effect of thickening at least a portion of the upper part of the clarification container.

Looking back for comparison purposes, FIG. 6 illustrates an electrical schematic diagram of the first resistive element RE _a and the second resistive element RE _b . The resistive element RE _a includes a length L _a , a cross-sectional area A _a, and a resistivity ρ _a . The resistance element RE _b includes a length L _b , a cross-sectional area A _b, and a resistivity ρ _b . Each resistance element may be, for example, a wire. As shown in FIG. 6, the resistance element RE _a and the resistance element RE _b are connected in parallel between the two bus bars 64 and 66. The potential E is imposed between the two bus bars. Assuming that the resistance elements are all the same (where L _a = L _b , A _a = A _b and ρ _a = ρ _b ), both of the resistance elements have the same resistance, that is, R _a = R _b (where, generally, The resistivity ρ is equal to the resistance R times the area A divided by the length L). Again, in this example, RE _a indicates the upper wall portion 44 _{a of the} clarification container 20, and the resistance element RE _b indicates the lower wall portion 44 _{b of the} clarification container 20. RE _a through current I _a is equal to the current through the RE _b I _b (ignoring other transmission loss). The total current I _t is I _a + I _b or E / (R _a R _b / (R _a + R _b )). The values are inserted, assuming that E is 10 volts and that R _a and R _b are each 5 ohms. Then I _a and I _b are each 2 amps, and the total current I _t is I _a + I _b = 4 amps. The total power P (assuming 100% efficiency) as heat consumption is P = I _t E. Insert the above values, P = 10 Volts × 4 Amps = 40 Watts.

The foregoing example assumes that the resistance element RE _{a is the} same as the resistance element RE _b . Referring now to FIG. 12, it is assumed that the cross-sectional area of _a part of the resistance element RE _a increases, so the resistance element RE _{a is} composed of two sections. That is, it is assumed that the resistance element RE _a includes two resistance element sections: a first resistance element section RE _a1 and a second resistance element section RE _a2 . RE _a1 includes a length L _a1 , a cross-sectional area A _a1 , a resistivity ρ _a1, and a resistance R _a1 . RE _a2 includes a length L _a2 , a cross-sectional area A _a2 , a resistivity ρ _a2, and a resistance R _a2 . RE is further assumed that the length _A1 of the first resistive element section length L _a1 RE L _{a2 a2} longer than the second resistive element segments, and a second resistive element section RE _{a2 a2} is greater than the cross sectional area A of the first resistor the cross-sectional area A _a1 RE _a1 element section. In other words, it is assumed that the first resistance element RE _{a is} composed of two sections, and the sections are arranged end-to-end in series. The thickness of the second section is greater than the thickness of the first section, but the length ratio of the first section is The second section is much longer. It is assumed that both sections have the same resistivity as the second resistive element RE _b such that ρ _a1 = ρ _a2 = ρ _b . Therefore, it can be shown that the resistance of RE _a1 can better control the total resistance of RE _a (as a numerical example, considering two resistance elements in series, one of the resistance elements has a resistance of 100 ohms and the second resistance element has 5 ohms Resistance, the total resistance of the two series resistance elements is 105 ohms, which is not significantly different from the resistance of 100 ohm resistance elements).

Then in this example, the total resistance of the first resistance element RE _a = R _a = R _a1 + R _a2 , and the current I _a in the first resistance element is RE _a = E / R _a = E / (R _a1 + R _a2 ), and I _b = E / R _b . The current I _a in the legs is represented by the segments RE _a1 and RE _a2 , that is, the resistance element RE _a will be approximately determined by E / R _a1 . The current I _b will be the same as the current I _b related to FIG. 6. However, current I _a of the present embodiment will be distributed in the second resistive element in the cross-sectional area section RE _a2 A _a2, which is larger than the cross sectional area A _a2 A _a1 RE _a1 of a first resistive element section. Therefore, the heating of the second resistance element section RE _a2 will be less than the heating of the first resistance element section RE _a1 , and therefore, the temperature of the second resistance element section RE _a2 will be less than the temperature of the first resistance element section RE _a1 . . In the context of the clarification vessel 20, this situation has the effect of reducing the temperature of the clarification vessel at the location of the flange, where the current enters and / or leaves the clarification vessel and the current density tends to be maximum.

In yet another embodiment shown in FIG. 13, at least a portion of the upper wall portion 44a of the clarification container may include three length sections: the first length portion 44a ₁ and the second length portion 44a ₂ as described previously. , And the third length portion 44a ₃ . As shown previously, the upper wall portion of the first length portion 44a ₁ in the cross section includes the thickness t _a1 , and the upper wall portion of the second length portion 44a ₂ in the cross section includes the thickness ta ₂ , and t _a2 > t _a1 . The third part of the length of the cross section 44a ₃ comprises a thickness t _a3, t _a3 and equal to or greater than t _a1 is substantially equal to t _a2. The first length portion 44a _{1 is} positioned between the second length portion 44a ₂ and the third length portion 44a ₃ . One or both of the second length portion 44a ₂ or the third length portion 44a ₃ may be positioned adjacent to the flange 42.

One reason for clarifying the hot spot at the upper wall portion 44a of the container is caused by the high current density of the flange at a line with the electrode 49, which connects the flange to a current source. That is, the flange typically includes a protrusion or electrode that extends from the flange and is connected to a cable or bus bar that feeds current into the flange. If the current supplied to the flanges is increased to address greater heating needs, such as increased molten glass flow, higher current densities in the flanges in the area near the electrodes and clarification vessels (where the current is distributed from the electrodes to the flanges and Clarification Vessel) can form a temperature high enough in the flange and / or clarification vessel to cause premature rupture of the flange and / or clarification vessel by rapid oxidation of the material containing the flange and / or clarification vessel. This situation can be graphically illustrated with reference to FIGS. 14 to 16.

Figure 14 illustrates a side view of a clarification container that includes a wall having a thickness that changes circumferentially. The electrode 49 is positioned closest to the fining container wall 44 or to the flange 42 of the first portion 44a so that the current (eg, current density) in the portion above the clarifying container wall is maximized in the area of the wall 44, which is the area Consistent with electrode 49. That is, the current density at the top of the clarification container closest to the electrode 49 may be higher than the current density allowable by the material of the upper wall portion 44a of the clarification container, thereby potentially causing increased heating of the upper portion of the clarification container. Partially exposed to the atmosphere 52. This situation can be found in section 15 With the help of the figure, FIG. 15 illustrates a cross section of the clarification container of FIG. 14 at one of the flanges 42. A circuit generating a high current density is indicated by an arrow 60, and a region with a high current density is a region labeled Za.

To alleviate the high current density in the upper part of the clarification vessel, the electrode 49 may be positioned so that the electrode is closest to the lower part of the clarification vessel or the second wall portion 44b (as shown in Figure 16) so that the high current density is Appears in the clarification vessel, where the clarification vessel wall 44 contacts the molten glass region Zb. That is, the electrode 49 may be positioned at the bottom of the flange 42 and extend downward from the bottom. This case is particularly useful when the thickness of the lower wall portion is greater than the thickness of the upper wall portion.

Examples

Figure 17 illustrates a graph of temperature along the length of a clarification container that includes a cross-sectional wall thickness that is substantially uniformly circumferentially. In addition, as shown in Figure 18, the clarification container further includes a thickness band 75 positioned between the flanges, adjacent to and adjacent to the second flange (the farthest flange on the right side of the drawing) and along the clarification container It extends longitudinally by a distance of about 11 cm. The thickness band surrounds the clarification vessel and is greater than the thickness of the remainder of the clarification vessel wall, but the thickness of the thickness band itself is substantially uniform. The flanges are positioned at positions A and B. Curves 70, 72, and 74 represent modeled data generated with the help of Fluent® software, and circles and triangles represent actual data about clarification vessels obtained through thermocouples. Insulating material. The graph illustrates that the actual data typically mimics modeled data to help confirm the feasibility of the model and is used to represent the temperature along the length of the clarification vessel. Curve 70 indicates the temperature as a function of standardized length at the top of the clarification container, curve 72 indicates the temperature as a function of standardized length along the bottom of the clarification container, and curve 74 indicates the clarification container along the side of the clarification container (top of the clarification container) (Between the bottom and the bottom) as a function of length. The data shows that the temperature along the top of the clarification container is about 15 to 20 degrees Celsius higher than the temperature at the sides and bottom of the clarification container. As mentioned earlier, the presence of another wall portion that is thicker than the wall portion can reduce the current density at the location of the thicker wall portion, and this is supported by a model that illustrates only the temperature before the flange at B Descend (view figure 17 from left to right). However, as mentioned above, the lack of thickness differences (eg, changes in circumferential thickness) elsewhere along the clarification container results in high temperatures along other parts of the clarification container. The temperature drop at the flange (and, in particular, the flange at B) is due to the heat dissipation of the flange. That is, each flange acts at least partially as a heat sink, which dissipates heat conductively and radiatively. In addition, the flanges are modeled to be actively cooled by a cooling coil, which is positioned around the perimeter of each flange, through which cooling fluid flows. FIG. 19 is a graph illustrating a modeled current density in amperes per square millimeter (A / mm ² ) used in the case of FIG. 17, where a curve 76 represents a variation of the upper wall portion with a normalized length Current density, curve 78 represents the current density as a function of the normalized length in the lower wall portion, and curve 80 represents the current density as a function of the length at the side of the clarification container (the middle between the top and bottom of the clarification container). The data show that the current density increases only before the thickness band (again when viewing Figure 19 from left to right), where the current density at the thickness band decreases sharply.

Figure 20 illustrates a graph of temperature along the length of a clarification container (e.g., the clarification container of Figure 5) that includes an upper wall portion and a lower wall portion, wherein the cross-sectional wall thickness of the upper wall portion is less than the lower wall portion Its cross-sectional thickness. The clarification container of Figure 20 does not include a thickness band. Length is illustrated as normalized Length and temperature in degrees Celsius (° C). Curves 80, 82, and 84 represent modeled data generated with the help of Fluent® software. Curve 80 represents the temperature as a function of standardized length at the top of the clarification container, curve 82 represents the temperature as a function of standardized length along the bottom of the clarification container, and curve 84 represents the clarification container along the side of the clarification container (top of the clarification container) (Between the bottom and the bottom) as a function of normalized length. According to modeling, as in the foregoing example, the first flange is positioned at A and the second flange is positioned at B. The data shows that the temperature along the top of most of the clarification container is about 5 ° C to 10 ° C lower than the temperature at the sides and bottom of the clarification container (except for the location close to the flange at position B), where the temperature is shown to increase by more than Bottom temperature. This happens because the second flange is present at B. This increase can be mitigated by positioning the electrode to extend downwardly from the flange closest to the bottom of the clarification container or by including a thickness band or at least an upper portion including a thin first upper portion and a thick second upper portion. section. FIG. 21 is a graph illustrating a modeled current density in amperes per square millimeter for the case of FIG. 20. Curves 86, 88, and 90 represent modeled data generated with the help of Fluent® software. Curve 86 represents the current density as a function of the standardized length at the top of the clarification container, curve 88 represents the current density as a function of the standardized length along the bottom of the clarification container, and curve 90 represents the clarification container along the side of the clarification container (clarification container (Between the top and bottom) of the current density as a function of normalized length. The graph illustrates the generally uniform current density (e.g., current density at the top, bottom, and midpoints) around the circumference of the clarification container as a result of changing the thickness of the circumference within the intermediate length of the clarification container between the two flanges. Shown), and the current density at the flange is also shown There is an increase due to the flange being used to direct all current in or out of the clarification vessel. Thus, a flange may be considered a collection node or a distribution node. This effect of clarifying the increased current density at the flanges in the container (which effect can ultimately lead to increased temperature) can be mitigated by including a thickness band as described above, or better including a thick second upper part, because Modeling has illustrated that including a thickness band around the entire perimeter of the clarification vessel has no substantial effect on the temperature in the lower portion of the clarification vessel. Therefore, using only the thin portion at the upper part of the clarification container represents the cost savings of precious metals relative to the alternative of increasing the thickness of the clarification container around the entire circumference.

It should be noted that although the foregoing embodiments are described in the context of clarifying a container, the principles and configurations disclosed herein are applicable to other containers used to transfer molten glass regardless of whether the free surface of the molten glass is present in the container. For example, the principles and constructions disclosed herein can be applied partially or completely to connection conduit 18, connection conduit 24, agitation container 22, transfer container 28, outlet conduit 30 and inlet 32 or any other metal container, and the application in detail These containers are directly electrically heated.

It will be apparent to those skilled in the art that various modifications and changes can be made to the embodiments of the present disclosure without departing from the spirit and scope of the embodiments of the present disclosure. Therefore, if these modifications and changes are within the scope of the accompanying patent application scope and the equivalent of the accompanying patent application scope, this disclosure is intended to cover such modifications and changes.

Claims (10)

A molten glass transfer device comprising: a container including a wall; a plurality of flanges surrounding the container and configured to direct a current to the wall and the current from the wall And wherein at least a portion of the wall between at least two consecutive spaced flanges of the plurality of flanges includes a first wall portion positioned at a top of one of the containers; and a second A wall portion, the second wall portion being positioned at a bottom of the container, and in a first cross-section of the at least one portion of the wall, a thickness of one of the first wall portions is less than a thickness of one of the second wall portions . The molten glass transfer apparatus according to claim 1, wherein the thickness of the first wall portion in the cross section is uniform. The molten glass transfer apparatus according to claim 1, wherein the thickness of the second wall portion in the cross section is uniform. The molten glass conveying device according to any one of claims 1 to 3, further comprising a third wall portion positioned between the first wall portion and the second wall portion, and A thickness of one of the third wall portions in the cross-section is greater than the thickness of the second wall portion. The molten glass transfer device according to claim 1, wherein the at least a portion of the wall includes: a first length portion, the first cross section is located in the first length portion; and a second length portion, the second The length portion is adjacent to the first length portion in a direction parallel to a longitudinal axis of the container, the second length portion is adjacent to the first flange of one of the two continuous flanges, and is located in the second length portion. In a second cross section, a thickness of one of the second wall portions is smaller than a thickness of one of the first wall portions. The molten glass transfer device according to claim 5, further comprising a third length portion, the third length portion being spaced apart from the second length portion and adjacent to the first length portion, and located at the third length In a third cross section of one of the portions, a thickness of one of the second wall portions is smaller than a thickness of one of the first wall portions. A method of forming glass, the method comprising the steps of: melting a batch in a melting furnace; flowing molten glass from the melting furnace through a container so that the molten glass includes a free surface in the container, and An atmosphere is positioned above the free surface, the container includes a wall, the wall includes a first wall portion, the first wall portion is positioned at a top of the container, and includes a first thickness; and a second wall portion The second wall portion is positioned at a bottom of the container and includes a second thickness, and in a first cross-section of the container, the second thickness is greater than the first thickness; and wherein the molten glass flow is controlled, So that the molten glass flow does not flow out of a surface of the first wall portion. The method of claim 7, wherein the container includes a third wall portion, the third wall portion includes a third thickness positioned between the first wall portion and the second wall portion, and in the first In a cross section, the third thickness is greater than the first thickness and the second thickness. The method of claim 7, wherein the free surface intersects the second wall portion. The method of any one of claims 7 to 9, wherein during the flow, one of the first wall portions is at least 5 degrees Celsius cooler than one of the second wall portions.