JP2015508371A - Downdraw apparatus and method for providing a clean glass manufacturing environment - Google Patents

Abstract

A downdraw glass manufacturing apparatus (10) for providing a clean glass manufacturing environment is arranged to deliver an enclosure (12), a molded body (30) disposed within the enclosure, and molten glass to the molded body. And a conduit (40) having an outlet arranged to deliver fluid to the enclosure and pressurize the enclosure. The conduit is made of a material that does not produce particles that itself cause onclusion formation and is located at the same elevation as the molded body. The enclosure may be a muffle chamber, which includes a muffle door (20) at the bottom of the muffle chamber, through which the glass formed by the molded body passes as the outlet of the muffle chamber. Located inside and outside the muffle door. In addition, a gas source (44) connected to the conduit may further be included, the gas source being configured to deliver a gas whose airborne particulate cleanliness class is 100 or cleaner.

Description

Explanation of related applications

  This application claims the benefit of priority of US Provisional Patent Application No. 61 / 563,927, filed Nov. 28, 2011, the contents of which are incorporated herein by reference in their entirety. To do.

  The present invention relates to an apparatus and method for producing glass, and more particularly to an apparatus and method for producing glass length in a downdraw process.

  The fusion process for producing flat glass has become a preferred method in glass forming due to its exceptional ability to produce a superior glass surface quality. In the fusion process, the glass overflows the molded body so that the two separate melt streams merge into a glass ribbon, which maintains the surface quality of both outer surfaces. The surface quality of glass is most important for customers who use glass to manufacture displays, such as flat panel displays, liquid crystal displays (LCDs), OLED displays, plasma displays, and field emission displays. Even small surface defects can cause retardation differences or other problems that can be seen by end users (eg, television viewers) as defects, dark spots, or light spots in the screen. A typical liquid crystal cell gap is less than 5 μm, so even a 1 μm surface disturbance results in a 20% change in the light path length from the surrounding area. In extreme cases, surface defects can be large enough to completely fill the cell gap, resulting in a short circuit. High quality LCD panels require exceptionally good surface quality of glass parts. The effects of surface defects are extremely significant in large generation size panels (eg, 8th and 10th generations), where even a single defect can render the entire sheet unusable. . One type of glass defect is described as “onclusion”.

  Onclusion is a particulate type defect that adheres to the surface of the molten glass during ribbon molding and may be partially embedded within the glass. Onclusion is a general term for the nature of defects and can have many root causes. A fusion draw device (FDM) for glass production is open at the bottom, allowing the air drawn in to freely circulate upward. This air can carry particulate matter (which causes defects) upward and even onto the molten glass. Furthermore, the general FDM refractory parts themselves fall off or sway depending on the steam and temperature, so that the particulate matter is taken into the air flow inside the FDM or forms defects on the glass surface. Can also occur. All of these fall into the onclusion category and result in glass loss. Due to its position on the sheet surface, onclusion is a significant defect class.

  Attempts have already been made to reduce the amount of air rising upward from the bottom of the FDM by the so-called chimney effect, thereby reducing the amount of onclusion. In general, these attempts include managing the pressure in the FDM.

  The inventors have found that simply managing the pressure in the FDM is not sufficient to keep the level of on-clusion on the glass surface low. In addition, the ability to reduce onclusion while maintaining pressurization, thickness control, i.e., keeping thickness variation across the glass width low, affects the way pressure is managed in the FDM. receive. Specifically, the inventors found that pressurization while establishing a clean air environment at a location in the FDM where onclusion may occur is healthy and sustained to achieve onclusion reduction. We found that this is a possible technique. The clean air environment inside the FDM affects the ability of each to reduce onclusion, from the perspective of the equipment through which the gas delivered to pressurize the FDM passes, and the particulate matter it contains. It can be established by appropriate selection of the quality of the gas itself, as well as the location of the gas delivery to the FDM. The present disclosure relates to apparatus and methods that increase the pressure inside the FDM appropriately (ie, while establishing a clean air environment), thereby reducing onclusion while maintaining thickness control.

  Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from the description, or may be illustrated by the various embodiments illustrated in the description and accompanying drawings. Will be recognized by implementing. The foregoing general description and the following detailed description are merely exemplary of the various aspects and are intended to provide an overview or arrangement for understanding the nature and characteristics of the claimed invention. Please understand that.

  The accompanying drawings are included to provide a further understanding of the principles of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments, and together with the description, serve to explain, by way of example, the principles and operation of the invention. It should be understood that the various features disclosed in this document and the drawings can be used in any combination and all in combination. By way of non-limiting example, various features may be combined with each other as specified in the following embodiments.

According to a first aspect, a downdraw glass manufacturing apparatus is provided, the apparatus comprising:
Enclosure,
A molded body, placed inside the enclosure,
An injection tube arranged to deliver molten glass to the molded body; and
A conduit having an outlet arranged to deliver fluid to the enclosure and pressurize the enclosure, made from a material that does not react or corrode at temperatures near the upper molded body in the FDM ,conduit,
It has.

  According to a second aspect, an apparatus according to aspect 1 is provided, characterized in that the conduit is made from ceramic, glass ceramic, glass, platinum, iridium, palladium, rhodium or nickel.

  According to a third aspect, there is provided an apparatus according to aspect 1 or aspect 2, further comprising a gas source connected to the conduit, the gas source having a cleanliness class of airborne particulates of 100 or cleaner. It is configured to deliver a certain gas.

  According to a fourth aspect, an apparatus according to any one of aspects 1 to 3 is provided, characterized in that the conduit is located at the same elevation as the forming body.

  According to a fifth aspect, there is provided an apparatus according to any one of aspects 1 to 4, wherein the enclosure is a muffle chamber, and the muffle chamber is formed at a lower portion of the muffle chamber with glass formed by a molded body. It includes a muffle door that passes on the way, wherein the outlet of the conduit is located inside the muffle chamber and outside the muffle door.

  According to a sixth aspect, there is provided an apparatus according to aspect 5, wherein the muffle door includes a front plate made of a material having high thermal conductivity facing the bottom, and the muffle door is of the front plate. A muffle door chamber is further provided on the side opposite to the side on which the bottom is arranged.

According to a seventh aspect, there is provided a method of manufacturing a length of glass, the method comprising:
Flowing molten glass through a molded body such that the molten glass flows downwardly in the form of a ribbon from the molded body disposed within the enclosure;
Delivering fluid to the enclosure through a conduit made from a material that does not react or corrode at temperatures near the upper molded body in the FDM to pressurize the enclosure;
Flowing the ribbon out of the enclosure; and
Cutting the ribbon to form a length of glass;
including.

  According to an eighth aspect, the method of aspect 7 is provided, characterized in that the conduit is made from ceramic, glass ceramic, glass, platinum, iridium, palladium, rhodium, or nickel.

  According to a ninth aspect, there is provided the method of aspect 7 or aspect 8, characterized in that the fluid is a gas having a cleanliness class of airborne particulates of 100 or cleaner.

  According to a tenth aspect, the method of any one of aspects 7 to 9 is provided and further comprises the step of delivering a fluid at the height of the molded body.

  According to an eleventh aspect, there is provided the method of any one of aspects 7 to 10, wherein the enclosure is a muffle chamber, the muffle chamber includes a muffle door through which the ribbon passes as it exits the muffle chamber, and the fluid Is further included in the muffle chamber at a position outside the muffle door.

  According to a twelfth aspect, the method of aspect 11 is provided, wherein the muffle door includes a front plate made of a material having high thermal conductivity facing the bottom, and the muffle door is of the front plate. A muffle door chamber is further provided on the side opposite to the side on which the bottom is arranged.

According to a thirteenth aspect, a downdraw glass manufacturing apparatus is provided, the apparatus comprising:
Enclosure,
A molded body, placed inside the enclosure,
An injection tube arranged to deliver molten glass to the molded body; and
A conduit having an outlet arranged to deliver fluid to the enclosure to pressurize the enclosure; and
A gas source connected to the conduit and configured to deliver a gas having a cleanliness class of airborne particulates of 100 or cleaner;
It has.

  According to a fourteenth aspect, there is provided an apparatus according to aspect 13, characterized in that the conduit is located at the same elevation as the forming body.

  According to a fifteenth aspect, there is provided an apparatus according to the aspect 13 or aspect 14, wherein the enclosure is a muffle chamber, and the muffle chamber is formed in the lower part of the muffle chamber when the glass molded with the molded body exits. Including a passing muffle door, wherein the outlet of the conduit is located inside the muffle chamber and outside the muffle door.

According to a sixteenth aspect, there is provided a method of manufacturing a length of glass, the method comprising:
Flowing molten glass through a molded body such that the molten glass flows downwardly in the form of a ribbon from the molded body disposed within the enclosure;
Delivering a fluid, which is a gas having a cleanliness class of airborne particulates of 100 or cleaner, through a conduit to pressurize the enclosure;
Flowing the ribbon out of the enclosure; and
Cutting the ribbon to form a length of glass;
including.

  According to a seventeenth aspect, the method of aspect 16 is provided and further comprises the step of delivering fluid at the elevation of the molded body.

  According to an eighteenth aspect, there is provided the method of aspect 16 or aspect 17, wherein the enclosure is a muffle chamber, the muffle chamber includes a muffle door through which the ribbon passes as it exits the muffle chamber, The method further includes the step of delivering to a position inside the muffle chamber and outside the muffle door.

Schematic diagram of the fusion draw device Schematic showing the relationship between the number of onclusions and the amount of pressure in the muffle enclosure Schematic showing the relationship between thickness variation and pressure in the muffle door Schematic diagram of glass manufacturing equipment

  In the following detailed description, for purposes of explanation and not limitation, example embodiments disclosing specific details are set forth in order to provide a thorough understanding of various principles of the invention. However, it will be apparent to one of ordinary skill in the art who has benefited from the present disclosure that the present invention may be practiced in other embodiments that depart from the specific details disclosed herein. Moreover, descriptions of well-known devices, methods, and materials may be omitted so as not to obscure the description of various principles of the invention. Finally, wherever applicable, the same reference numbers indicate similar elements.

  As used in this document, for example, top, bottom, right, left, front, back, top, bottom, etc., terms that refer to the direction of the drawing and are absolute It is not intended to be.

  Unless explicitly stated otherwise, any method specified herein is not intended to be construed as requiring that the steps be performed in any particular order. Therefore, if the order in which these steps are performed is not actually stated in a method claim, or specifically stated in the claim or description, these steps should be limited to a particular order. If not, it is not intended in any way that order is inferred. This includes all possible manifestations, including logic issues regarding the placement of steps or operational flows, obvious meanings derived from grammar construction or punctuation, and the number or type of embodiments described herein. It is applied as a principle of interpretation that is not done.

  In this document, the singular includes the plural object unless the context clearly dictates otherwise. Thus, for example, reference to a “component” includes aspects having two or more of this component unless the context clearly indicates otherwise.

  The present disclosure is sound and sustainable for pressurizing while establishing a clean air environment at a location where onclusion within a fusion draw device (FDM) may be formed and for reducing onclusion The present invention relates to an apparatus and a method for providing a simple technique.

  One approach to establishing a clean air environment within the FDM is to deliver gas through a facility that does not itself generate onclusion particles. This can be done by appropriate selection of the material of the conduit through which the gas delivered to the FDM passes to pressurize the FDM area. As long as the fluid delivery lumen of the conduit is made from such material, the entire conduit need not be made from such material. As a conduit for delivering a gas without itself producing particles that lead to onclusion, we are near the upper molding body in the FDM when in contact with a nitrogen or oxygen rich fluid source. Very suitable conduits made from high melting point materials that do not react, deteriorate, or corrode—these will lead to particle formation—at temperatures typically seen at, for example, 900-1300 ° C. I found. For example, the conduit may be made from ceramic, glass ceramic, or glass. The conduit may also be made from a metal such as, for example, platinum, iridium, rhodium, palladium, or nickel.

  A second approach to establishing a clean air environment within the FDM is to use a gas that does not itself contain a large amount of particles that lead to onclusion. The present inventors are “Airborne Particulate Cleanliness Classes” (Institute of Environmental Sciences and Technology, USA, Zip Code 60056, Mount Prospect, Illinois, East Northwest Highway 940). A source of particles whose class 100 (M3.5) or cleaner gas, as measured under US Federal Standard 209E, available) increases the pressure inside the FDM and at the same time leads to onclusion I found it suitable for not.

  A third approach to establishing a clean air environment within the FDM relates to the location where gas is delivered to the FDM. More specifically, the present inventors have found that when gas is sent to the FDM at the altitude of the molding body and inside the muffle chamber but outside the muffle door, it leads to a low level of onclusion.

  An embodiment of a fusion draw apparatus (FDM) including a clean air environment will be described with reference to FIG. The FDM 10 includes an upper enclosure or muffle chamber 12 in which the glass ribbon 4 is formed, and a lower enclosure 14 in which the glass ribbon 4 is pulled and thermally regulated until it exits the lower opening 16. Including. The glass sheet 8 is then separated from the lower end of the ribbon 4 using techniques well known in the art. Although the sheet 8 is shown as being separated from the ribbon 4 in the figure, instead of forming a ribbon 4 of any length, for example when winding glass, it is separated from the rest. May be. That is, it is to be understood that the term “glass sheet” is used throughout this specification for convenience of reference, and that the term may also include a length of glass that is wound.

  The muffle chamber 12 surrounds a forming body 30 for forming the glass ribbon 4. The molded body 30 receives molten glass from the injection tube 36. The glass flows in the form of two separate streams on opposing merged side surfaces 32 of the molded body 30, and these separated streams recombine at the bottom 34 of the molded body 30 to form a glass ribbon 4 having a thickness 6.

  A pair of muffle door housings 20 are located in the lower part of the muffle chamber 12 and are used to control the variation of the thickness 6 in the direction across the glass ribbon 4, that is, in the direction entering and exiting the plane of FIG. One muffle door housing 20 is disposed on each side of the ribbon 4, thereby forming an opening through which the glass ribbon 4 extending to the lower enclosure 14 passes. Since the muffle door housing 20 has the same structure, only one will be described in detail. Similarly, various principles may be described in connection with one of the illustrated muffle door housings 20 with the understanding that the same principles are equally applicable to the other muffle door housing 20. The muffle door housing 20 is disposed so as to face the molded body 30 and the glass ribbon 4 when having a viscosity exceeding its softening point. The muffle door housing 20 includes a front plate 22, a muffle door chamber 24, and a plurality of pipes 26. Each tube 26 includes an outlet within the muffle door chamber 24.

  The front plate 22 is formed of a material having a constant high conductivity, low thermal expansion, and high emissivity regardless of time and temperature. The front plate 22 is preferably formed from a flat plate of silicon carbide, and its backside is any support structure that can generate heat discontinuity across the plane of the flat plate, except at the border edges. It is preferable not to contact.

  The fluid source 28 is coupled to deliver fluid to the tube 26. Although only one tube 26 is shown on each side of the molded body 30, there are typically a plurality of tubes 26 arranged along the width direction of the glass ribbon 4, i.e. each of the molded bodies 30. Any suitable number of tubes 26 can be employed on the side, with the number generally depending on the width of the glass ribbon 4. The fluid may be, for example, air, compressed air, or any other suitable gas. Throughout this specification, the term “air” or “air flow” will be used for convenience, but is intended to include all suitable types of gases or other fluids. Fluid is delivered from a fluid source 28, passes through the tube 26, and strikes the front plate 22 and enters the muffle door chamber 24 to locally control its temperature. The local temperature at a certain point of the front plate 22 then affects the temperature, i.e. the viscosity, of the adjacent part of the glass ribbon 4 and consequently the thickness. The fluid flow through each tube 26 can be individually adjusted in a manner well known in the art to control the thickness gradient across the ribbon 4.

  There are various structures in the lower enclosure 14 that are used to move and / or guide the glass ribbon 4 downward, but these structures are not shown to simplify the drawing. Various other structures may also be present in the enclosure 14 to thermally condition the ribbon 4 as it passes through the enclosure 14 or to control the heat loss of the ribbon 4. .

  There are various openings in the muffle chamber 12 and the lower enclosure 14 that allow air to leak out of the FDM 10. These openings are intended openings--for example, electrical connections, fluid connections, access to and / or access to equipment in FDM 10, water cooling ports, resistance heaters, coil windings for thermocouples, and / or tubes. -And / or unintended cracks or holes for 26. Even when a seal is provided for equipment that is inserted through the intended opening, there may still be a leak in the seal that allows outflow from the FDM 10. In addition to air leakage from the FDM 10, there is a flow that flows upward in the direction of the arrow 13 due to a thermal gradient inside the FDM 10 itself. This flow may draw air from the lower opening 16 and carry the particles along with this air from the external area of the FDM 10 or from particle sources in the lower enclosure 14. When the particles move upward through the FDM 10 to the area of the muffle door housing 20, the particles adhere to the glass ribbon 4 or are embedded in the glass ribbon 4 to perform onclusion as described above. There is a possibility of forming. That is, it is desirable to minimize the upward flow in the FDM 10, particularly in the area of the muffle door housing 20.

  One technique for minimizing the flow of the FDM 10, particularly within the area of the muffle door housing 20, is to pressurize the muffle chamber 12. However, simple pressurization of the muffle chamber 12 is not sufficient to reduce onclusion. In addition, a clean air environment should be established. Pressurization by appropriately selecting the equipment through which the pumped gas passes to pressurize the muffle chamber 12, the quality of the gas itself, and the location of the gas delivery, each affecting the ability to reduce onclusion A clean and clean air environment can be established in the muffle chamber 12.

  One approach to establishing a clean air environment within the FDM is to deliver gas through a facility that does not itself generate onclusion particles. This can be done by appropriate selection of the material of the conduit through which the gas delivered to the FDM passes to pressurize the FDM area. As long as the fluid delivery lumen of the conduit is made from such material, the entire conduit need not be made from such material. As a conduit for delivering a gas without itself producing particles that lead to onclusion, we are near the upper molding body in the FDM when in contact with a nitrogen or oxygen rich fluid source. Very suitable conduits made from high melting point materials that do not react, deteriorate, or corrode—these will lead to particle formation—at temperatures typically seen at, for example, 900-1300 ° C. I found. For example, the conduit may be made from ceramic, glass ceramic, or glass. The conduit may also be made from a metal, for example, platinum, iridium, rhodium, palladium, or nickel. In practice, the melting point of this material should be selected to be higher than the highest temperature expected in the FDM, but this requirement is minimal. Further, as noted above, the selected material should be such that it does not react, degrade, or corrode when contacted with a nitrogen or oxygen rich fluid source, since such reactions, Degradation, or corrosion, is due to the formation of particles that lead to onclusion formation. Adjusting the delivered fluid (to ensure that the fluid does not contain particles that lead to onclusion formation) by using a conduit that does not itself generate onclusion particles and / or Or equipment for filtering can be located outside the high temperature environment of the FDM. This not only leads to longer equipment life, but also makes it easier to perform equipment maintenance services.

  Referring to FIG. 1, according to one embodiment, a conduit 40 having an outlet 42 extends into the muffle chamber 12. The other end of the conduit 40 is disposed outside the high temperature environment inside the FDM. The outlet 42 is disposed in the muffle chamber 12 so as to deliver gas from the fluid source 44. The conduit 40 may be made of, for example, ceramic, glass ceramic, glass, platinum, iridium, rhodium, palladium, or nickel. Although only one conduit 40 is shown on each side of the molded body 30, any suitable number of these conduits can be used to achieve the desired pressurization of the muffle chamber 12. The conduit 40 may be arranged at various positions along the width direction of the muffle chamber 12 (extending perpendicular to the plane of FIG. 1). Further, the conduits 40 may be arranged so as to extend at both ends of the muffle chamber, that is, in a direction parallel to the width of the muffle chamber 12. The gas sent into the muffle chamber 12 pressurizes the muffle chamber 12, thereby reducing the influence of the rising flow in the direction of the arrow 13, so that the particles in the rising air flow are included in the glass ribbon 4. The opportunity to form John is reduced. Furthermore, for the equipment used to deliver the pressurized air, i.e. for the conduit 40 made of a material that itself does not produce particles that will form onclusions. A clean air environment is formed in the muffle chamber 12.

  A second technique for establishing a clean air environment in the FDM is to pressurize the FDM with a gas that does not itself contain a large amount of particles that lead to onclusion. We have observed that a gas with a cleanliness class of airborne particulates of 100 (M3.5) or cleaner as measured by US Federal Standard 209E increases the pressure inside the FDM and at the same time turns on itself. It was found that it is suitable because it does not become a source of particles that lead to clusions. The fluid source 44 is configured to deliver to the conduit 40 a gas of the stated cleanliness (ie, the cleanliness class of its airborne particulate is 100 (M3.5) or cleaner). The fluid source 44 has high efficiency particle attraction (HEPA) filtration at its output sufficient to deliver the stated cleanliness of air, eg, air compressor, pump, fan. , Blower, or other air handler. Alternatively, if a suitable cleanliness gas is readily available, the fluid source 44 need not include filtration at its output. Although the fluid source 44 is illustrated as being connected to only one conduit 40, one fluid source 44 is practical for delivering a desired amount of pressurized gas to the muffle chamber 12. Any number of conduits 40 may be connected. For example, one fluid source 44 may be connected to the conduits 40 on both sides of the molded body 30. Further, although the fluid source 44 is illustrated as being separate from the fluid source 28, this need not be the case. That is, the fluid source 44 may be connected to both the conduit 40 and the tube 26.

  A third technique for establishing a clean air environment in the FDM relates to the location where the pressurized gas is delivered to the FDM. More specifically, the present inventors have found that when gas is sent to the FDM near the same altitude as the molded body and outside the muffle door chamber, it leads to low-level onclusion.

  According to one aspect of a third approach for establishing a clean air environment, referring to FIG. 1, the conduit 40 is positioned such that the outlet 42 is positioned at substantially the same elevation in the FDM 10 as the molded body 30. . That is, the molded body 30 is disposed at a certain height above the lower opening 16 in the FDM 10. Supplying air at the altitude of the forming body 30 increases the pressure near the bottom 34 and the side surface 32, thereby causing the particles to reach the glass at locations where they may form onclusions on the glass surface. The amount is kept to a minimum.

  According to another aspect of the third approach for establishing a clean air environment, referring again to FIG. 1, the outlet 42 is located inside the muffle chamber 12 but outside the muffle door chamber 24.

  It is not desirable to supply air into the muffle door chamber 24 in an attempt to pressurize the muffle chamber 12. In particular, increasing the total volume of air within the muffle door housing 20 increases the pressure within the muffle chamber 12, which helps reduce the level of onclusion as shown schematically in FIG. However, the additional air supplied into the muffle door housing 20 results in an increase in pressure in the muffle door chamber 24, which causes the air to leak out in an uncontrolled manner toward the glass ribbon 4, schematically shown in FIG. This leads to local thickness variations as shown. That is, if the total pressure inside the muffle chamber 12 is increased using the pressure inside the muffle door housing 20, that is, inside the muffle door chamber 24, the thickness variation is negatively affected. On the other hand, when the gas was actively sucked out from the muffle door chamber 24 so that the air did not leak toward the ribbon 4, the level of onclusion was increased. That is, to increase the pressure inside the muffle chamber 12 (to reduce onclusion) without increasing the pressure inside the muffle door housing 20 (which leads to undesirable thickness variations) Air may be supplied to the outside of the muffle door chamber 24 inside the muffle chamber 12. In addition, this location—inside the muffle chamber but outside the muffle door housing—minimizes the impact of other airflow inside the muffle on the chamber.

  To improve the existing FDM to implement the concepts described herein, existing tubes 26 that are unnecessary for thickness control can be used, and the above-described concepts can help reduce onclusion. In particular, the tube 26 may be retracted from its original position so that its outlet is outside the muffle door chamber 24 but is still in the muffle chamber 12. Thereafter, fluid from the fluid source 28 may be delivered to the muffle chamber 12 to increase the pressure in the muffle chamber 12. Further, instead of using fluid from the fluid source 28, the fluid source 44 (i.e., one that delivers air with a cleanliness class of airborne particulates of 100 or cleaner), the outlet of the muffle door chamber 24. It may be connected to an existing tube 26 that is external but still within the muffle chamber 12. In this arrangement, air with a cleanliness class of airborne particulates of 100 or cleaner can be delivered to the muffle chamber 12. Thus, the existing tube 26 can be used to help create a clean environment within the FDM 10.

  Here, a method of manufacturing the glass sheet 8 using the concept described in this document will be described.

  FIG. 4 shows an exemplary glass manufacturing system 100 using a fusion process, in which a glass sheet 8 can be manufactured using the concepts described above. The glass manufacturing system includes a melting tank 110, a clarification tank 115 (such as a clarification tube), a mixing tank 120 (such as a stirring chamber), a delivery tank 125 (such as a bowl), and the FDM 10. A glass material is introduced into the melting tank 110 and melted as indicated by an arrow 112 to form a molten glass 126. The fining tank 115 includes a hot processing area that receives molten glass 126 (not shown in this position) from the melting tank 110, where bubbles are removed from the molten glass 126. The clarification tank 115 is connected to the mixing tank 120 by a connecting pipe 122. The mixing tank 120 is connected to the delivery tank 125 by a connecting pipe 127. The delivery tank 125 passes the molten glass 126 through the downcomer 130 and delivers it into the FDM 10 that includes the inlet 36, the molded body 30, and the traction roller assembly 140. Molten glass flows from the downcomer 130 into the inlet 36 that leads to the molded body 30. The molded body 30 includes a trough that receives the molten glass 126, which then overflows and fuses at the bottom 34 after flowing down the two sides 32 of the molded body 30. The bottom 34 is the location where the two side surfaces 32 are joined, and at this bottom 34 the two overflowing molten glass 126, ie, the walls of the molten glass 126, recombine (eg, refuse) and the pulling roller assembly At 140, a glass ribbon 4 is formed that is drawn downward. Details of the FDM 10 are similarly described above in connection with FIG. While specific details of an exemplary glass manufacturing system are described, molded bodies and glass manufacturing systems are well known in the art, and those of ordinary skill in the art will readily identify suitable molded bodies and / or glass manufacturing systems. Note that you may choose.

  Referring back to FIG. 1, when molten glass is delivered to the forming body 30, the area inside the FDM 10 is adequate to reduce the chance that the particles will reach the glass where they can form onclusions. To establish a clean air environment inside the FDM 10. In particular, in order to create such a clean air environment inside the FDM, the following concept, for example, ceramic, glass ceramic, glass, platinum, iridium, rhodium, palladium, or nickel, to pressurize the FDM 10 Such as low-particle release materials (i.e., reaction, degradation at temperatures of 900-1300C typically seen near the molded body in FDM when contacted with a source of nitrogen or oxygen rich fluids, Or the gas may be delivered to the FDM 10 via a conduit 40 made from non-corroding; the gas may be delivered to the FDM 10 at the same altitude as the molded body 30 to pressurize the FDM 10; Gas may be delivered to the muffle chamber 12 outside the muffle door enclosure 24; and The gas delivered to the FDM 10 may have an airborne particulate cleanliness class of 100 or cleaner; any one or more of the concepts such as alone or in any combination and all combinations May be used.

  It should be emphasized that the above-described embodiments of the present invention, particularly any "preferred" embodiments, are merely possible examples and are merely illustrative for a clear understanding of the various principles of the invention. Many variations and modifications may be made to the above-described embodiments of the invention without departing substantially from the spirit and various principles of the 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.

  For example, although the above description is made in the context of a fusion draw, a slot draw molded body could be used as the molded body 30.

4 Ribbon 8 Sheet 10 FDM
DESCRIPTION OF SYMBOLS 12 Muffle chamber 20 Muffle door housing 22 Front plate 24 Muffle door chamber 26 Pipe 28, 44 Fluid source 30 Molding body 34 Bottom part 36 Injection pipe 40 Conduit 42 Outlet 126 Molten glass

Claims (12)

In downdraw glass manufacturing equipment,
Enclosure,
A molded body disposed within the enclosure;
An injection tube arranged to deliver molten glass to the molded body; and
900-1300 ° C. when in contact with a source of fluid rich in nitrogen or oxygen having an outlet arranged to deliver fluid to the enclosure and pressurize the enclosure Conduits made from materials that do not react, deteriorate, or corrode at temperatures in the range of
A device characterized by comprising: In downdraw glass manufacturing equipment,
Enclosure,
A molded body disposed within the enclosure;
An injection tube arranged to deliver molten glass to the molded body; and
A conduit having an outlet arranged to deliver fluid to the enclosure to pressurize the enclosure; and
A gas source connected to the conduit and configured to deliver a gas having a cleanliness class of airborne particulates of 100 or cleaner;
A device characterized by comprising:   3. An apparatus according to claim 1, wherein the conduit is made from ceramic, glass ceramic, glass, platinum, iridium, rhodium, palladium, or nickel.   And further comprising a gas source connected to the conduit, the gas source configured to deliver a gas whose airborne particulate cleanliness class is 100 or cleaner. The apparatus according to claim 1 or 3.   5. A device according to claim 1, wherein the conduit is located at the same elevation as the forming body.   The enclosure is a muffle chamber, and the muffle chamber includes a muffle door at a lower portion of the muffle chamber through which glass formed by the molded body passes, and the outlet of the conduit is connected to the muffle chamber. 6. The device according to claim 1, wherein the device is located inside the chamber and outside the muffle door. A method for producing a length of glass,
Flowing molten glass through the molded body such that the molten glass flows downwardly in the form of a ribbon from the molded body disposed within the enclosure;
To pressurize the enclosure, the fluid is passed through a conduit made from a material that does not react, deteriorate, or corrode at temperatures in the range of 900-1300 ° C. when contacted with a nitrogen or oxygen rich fluid source. Delivering to the enclosure;
Flowing the ribbon out of the enclosure; and
Cutting the ribbon to form a length of glass;
A method comprising the steps of: A method for producing a length of glass,
Flowing molten glass through the molded body such that the molten glass flows downwardly in the form of a ribbon from the molded body disposed within the enclosure;
Delivering a fluid that is a gas having a cleanliness class of airborne particulates of 100 or cleaner to pressurize the enclosure through a conduit to the enclosure;
Flowing the ribbon out of the enclosure; and
Cutting the ribbon to form a length of glass;
A method comprising the steps of:   9. A method according to claim 7 or 8, characterized in that the conduit is made from ceramic, glass ceramic, glass, platinum, iridium, palladium, rhodium or nickel.   10. A method according to claim 7 or 9, wherein the fluid is a gas having a cleanliness class of airborne particulates of 100 or cleaner.   11. A method according to any one of claims 7 to 10, further comprising the step of delivering the fluid at an elevation of the forming body.   The enclosure is a muffle chamber, the muffle chamber includes a muffle door through which the ribbon exits the muffle chamber, and further the fluid is positioned within the muffle chamber and outside the muffle door; 12. A method according to any one of claims 7 to 11 further comprising the step of delivering.

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