JP2010520141A - Glass refining equipment - Google Patents

Abstract

Provided is a clarification container and a molten glass clarification device provided with a cradle that supports the clarification container and prevents oxidation. High cradle sidewalls and bed material extending above the fining vessel enhances the cradle's support and antioxidant capabilities. Keystone refractories engage the channels formed in the bed material to help prevent high temperature creep of the bed material and damage to the fining vessel.

Description

  The present invention relates to a molten glass clarification apparatus, and more particularly to support and protection of a noble metal clarification container.

  A typical manufacturing process for glassware begins with melting raw feed materials such as metal oxides to form molten glass. The melting process not only forms glass, but also forms various unwanted by-products, including various gases such as oxygen, carbon dioxide, carbon monoxide, sulfur dioxide, sulfur trioxide, argon, nitrogen and water vapor. It will also do. If these gases are not removed, they will continue to exist during the manufacturing process and the finished glass product will contain small and sometimes fine gaseous inclusions.

  In some glass products, small gaseous contents are not harmful. However, for other products, gaseous contents as small as 50 μm are unacceptable. One such product is a glass sheet used in the manufacture of display devices such as liquid crystal and organic light emitting diode displays. For such applications, the glass must have exceptional clarity, a clean surface, and be free of distortion and inclusions.

  A fining agent is usually added to the feed to remove gaseous inclusions from the molten glass. A fining agent is a polyvalent compound that, when cooled, becomes a reduced valence state that absorbs oxygen in the process and becomes an increased valence state that releases oxygen when heated. The released oxygen causes gas to form in the molten glass or molten product, coalesce and rise to the surface of the molten product where it is removed from the process. Heating is usually performed in a high temperature clarification container.

  A typical fining temperature for display grade glass can be on the order of 1700 ° C. At such a high temperature, a special metal or alloy is required to prevent the container from being destroyed. Platinum or platinum alloys such as platinum rhodium are usually used. Advantageously, platinum has a high melting temperature and does not break easily in glass. However, at such high temperatures, platinum or platinum alloys are susceptible to oxidation. Therefore, steps must be taken to prevent contact between the hot platinum fining vessel and atmospheric oxygen. Furthermore, since platinum is a noble metal and very expensive, the walls of the fining vessel are usually made as thin as possible. Therefore, the clarification container may require further physical support.

  According to one aspect of the present invention, a cradle that defines a trough, a container that conveys molten glass disposed in the trough, and a bed material that has a channel and is disposed between the cradle and the container. And a keystone for supporting at least a part of the bed material engaged with the channel of the bed material.

  According to another aspect of the present invention, a refractory cradle defining a trough and a wall extending upward from the trough, a container made of platinum disposed in the trough, and between the container and the cradle. A fireproof bed surrounding the container and having a channel on the top thereof, and a fireproof keystone disposed above the cradle, the fireproof keystone supporting the fireproof bed It features a glass refining device characterized by engaging with.

  Both the foregoing general description and the following detailed description illustrate embodiments of the invention and are intended to provide an overview or framework for understanding the nature and characteristics of the claimed invention. It will be understood. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the invention together with a detailed description of the invention and are used to explain the principles and operations of the invention.

Sectional drawing of the molten glass clarification apparatus by this embodiment which contains the cradle which supports a clarification container, and reduces oxygen of a clarification container 1 is a partial cross-sectional view of the container shown in FIG. 1 with various refractory blocks removed for illustration. 1 is a perspective view of the cradle shown in FIG. Enlarged sectional view of a fireproof bed according to this embodiment showing the channel and flange portion of the bed 4 is a perspective view of the bed material of FIG. 4 showing the channel and flange portion of the refractory bed without showing the fining container.

  In the following detailed description, for purposes of explanation and not limitation, embodiments disclosing specific details for a thorough understanding of the present invention are set forth. However, it will be apparent to those skilled in the art having the benefit of this specification that the present invention may be practiced in other embodiments that depart from the specific details disclosed herein. Furthermore, descriptions of well-known devices, methods and materials may be omitted so as not to obscure the description of the present invention. Finally, wherever it is applicable, the same reference number refers to the same member.

  1-3, according to the present invention, an apparatus 10 having a fining container 12, a cradle 14, a bed material 16, a plurality of refractory blocks 18 having various shapes and sizes, and a keystone 20 is provided. .

  The fining vessel 12 is typically constructed of a metal that can withstand very high temperatures, sometimes exceeding 1700 ° C. The noble metal container is preferably made of a metal selected from platinum group metals (eg, platinum, rhodium, iridium, ruthenium, palladium and osmium), or alloys thereof. However, other high temperature metals or alloys such as molybdenum may be used separately from or in combination with the platinum group metals or as alloys with other high temperature metals. In addition to receiving high temperature molten glass, which sometimes exceeds 1500 ° C., from a melting furnace or the like, the container 12 is used to further heat the molten glass. Accordingly, the container 12 itself may be heated. In certain embodiments, the container 12 is heated by passing a current through the metal container. However, other methods of heating the container 12 by known techniques such as flame may be used. It is preferable that the clarification container 12 is a cylindrical tube shape.

  The cradle 14 defines a trough 22 having a sidewall 24 extending upwardly therefrom. The cradle 14 is preferably made of a U-shaped trough. The cradle 14 is generally formed from a material that can withstand high temperatures that do not mechanically break. As used herein, unless otherwise defined, refractory means a material that can withstand high temperatures. The refractory material mainly consists of single or mixed refractory oxides of elements such as silicon, aluminum, magnesium, calcium and zirconium. However, non-oxide refractories also exist and include materials such as carbides, nitrides, borides and graphite. The actual composition of the refractory material depends on the temperature and environment in which the refractory material is used, and the material with which the refractory material contacts. The cradle 14 can be formed from, for example, alumina or melt cast zirconia.

  The clarification container 12 is disposed in the cradle 14 and surrounded by the bed material 16. As shown in FIG. 1, the cradle side wall 24 preferably extends further above the upper end of the fining vessel 12, and the bed material 16 is disposed between the vessel and the cradle. The bed material 16 begins as a refractory slurry that is flowed through the trough 22 to enclose the container 12 and then cures in place to become a solid refractory material 16 that becomes a protective bed for the fining container 12. Accordingly, the bed material 16 may be referred to as “castable” (eg, castable 16). The bed material 16 is in close contact with the clarification container 12, thereby maximally supporting the clarification container and preventing oxygen from spreading outside the container surface. Like the cradle 14, the bed material 16 should be able to withstand temperatures in excess of 1700 ° C. The bed material 16 is preferably a refractory compound, and can be made of, for example, high-purity alumina or zirconia.

  The cradle 14 is supported on the sides and bottom of the cradle by a refractory block 18 and is covered by a similar refractory block. Cradle 14 and refractory block 18 may be mounted in another enclosure, such as a steel enclosure 25 for structural support of the refractory block assembly. For example, the refractory block 18 may be Insalcor (registered trademark) brick.

  As shown in FIGS. 1 and 2, the keystone 20 is preferably disposed on the upper portion of the cradle side wall 24. The bed material 16 is poured into the cradle trough and reaches the tip of the keystone 20. The keystones 20 do not contact each other above the cradle 14, but instead extend inwardly from the side walls 24 so that each is less than half the distance between the side walls, so that the bed material 16 flows upward and the keys The tip of the stone 20 can be reached. The keystone 20 preferably also has an R portion at the extended edge 26. The net result is that the bed material 16 is engaged with the keystone 20 after the bed material 16 is cured. That is, the channel is formed in the upper part of the bed material to which the keystone 20 fits. Both the bed material 16 and the keystone 20 are capped by a further refractory block 18 so that the cradle 14 and the keystone refractory 20 are placed in the refractory block. The keystone 20 is preferably formed from a refractory, and may be made of, for example, molten zirconia or alumina.

  At high temperatures such that molten glass flows through the container 12, the bed material 16 is prone to compositional deformation or "creep" that can negatively affect the support function of the bed material. That is, the bed material may bend and the container 12 may be deformed or crushed. This is offset at the bottom of the container by the hydrostatic pressure of the molten glass flowing through the container. However, normally molten glass does not fill the clarification container; for this reason, there is a glass level line above which no hydrostatic pressure acts. If there is a creep due to the bed material, and pressure due to the weight of the bed material at the upper end of the clarification container 12 thereafter, and there is no internal force (for example, hydrostatic pressure) against the weight of the bed material, structural destruction occurs at the top of the container 12 there's a possibility that. By providing a structure that supports the bed material, the keystone 20 solves this problem.

  FIG. 3 is an enlarged view of the bed material 16 without the cradle 14 and the keystone 20 for explanation, and shows a portion between the bed material and the keystone. A glass level line 28 is also shown showing the level of the fining vessel 12 and the molten glass 30 in the fining vessel. Without support, the bed material 16 above the container 12 gradually creeps and exerts a downward force on the upper end of the container 12 so that the container 12 is deformed, putting the container at risk of structural failure. According to the present embodiment, opposed channels 32 are formed in the bed material 16, and the thickness “d” between the channels is smaller than the width “D” of the flange 34 above the channel. The keystone 20 engages the channel 32 on both sides of the bed material 16 so that the top of the bed material 16 is supported by the keystone 20 that engages the channel 32. In other words, the keystone 20 extends into the space above the container 12, and that space is filled with a portion of the keystone (e.g., keystone) when the uncured bed material 16 is filled. (On the upper surface of the R portion). When the bed material 16 hardens or otherwise changes to its hardened state, the bed material forms a shape (ie, channel 32) that interpolates the shape of the keystone extension. Therefore, the keystone 20 provides a support function by bearing the load of the bed material 16, thereby preventing the upper portion of the bed material 16 from being gradually bent due to the high temperature of the fining container 12. The channels 32 preferably extend in the longitudinal direction along the length of the bed material 16 while maintaining the same level in the overall height direction in an opposing relationship.

  As shown in FIG. 2, the apparatus 10 may further comprise at least one thermocouple 36 mounted in the bed material 16 so that the temperature of the fining vessel can be monitored. The at least one thermocouple may be selected based on the expected measurement temperature range and the accuracy required for the measurement. For example, type “B” and type “S” thermocouples are used to measure the temperature of a fining vessel (eg, metal tube 12). Both thermocouple types are noble metal thermocouples containing platinum and rhodium. Type “B” thermocouples are typically used for applications up to about 1800 ° C., while type “S” thermocouples are typically used for temperature measurements up to about 1600 ° C. Although it is preferred to use a type “B” thermocouple to measure the top of the fining vessel, a type “S” thermocouple is used to measure the temperature at the midpoint of the fining vessel. A lead 38 from at least one thermocouple is connected to a measuring device (not shown) that may be used for recording and / or controlling the fining vessel temperature.

  In some embodiments, the bottom corner of the cradle may be chamfered, as shown by dashed line 40. By removing unwanted material, the cradle 14 can be heated more uniformly and cracking of the cradle material can be minimized.

  It should be emphasized that the above-described embodiments of the present invention, and in particular any "preferred" embodiment, are examples that can be implemented and are described only for a clear understanding of the principles of the invention. is there. Many variations and modifications may be made to the embodiments of the invention described above without substantially departing from the spirit and principles of the present invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims.

10 Equipment 12 Clarification Container 14 Cradle 16 Bed Material 18 Fireproof Block 20 Keystone

Claims (8)

A glass refining device,
Cradle (14) defining trough (22),
A container (12) for transporting molten glass (30), arranged in the trough,
A bed (16) having a channel (32) and disposed between the cradle and the container; and a keystone (20) engaged with the channel and supporting at least a portion of the bed;
A glass refining apparatus characterized by comprising:   The apparatus of claim 1, wherein the container (12) is a tube.   3. Apparatus according to claim 1 or 2, characterized in that the container (12) is made of a metal selected from the group consisting of platinum, rhodium, iridium, ruthenium, palladium, osmium, molybdenum and alloys thereof.   A device according to any one of the preceding claims, characterized in that the side wall (24) of the cradle extends above the container (12).   An apparatus according to any one of the preceding claims, characterized in that the bed material (16) is arranged between the cradle and the container as a slurry.   6. The device according to claim 1, wherein the bed material (16) is made of a refractory material.   A device according to any one of the preceding claims, characterized in that the channel (32) extends along the length of the bed material (16).   The apparatus of claim 7, further comprising at least one thermocouple mounted in the refractory bed (16) for measuring the temperature of the container (12).

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