CN107531535B

CN107531535B - Apparatus and method for conditioning molten glass

Info

Publication number: CN107531535B
Application number: CN201680025840.0A
Authority: CN
Inventors: G·德安格利; P·拉龙泽
Original assignee: Corning Inc
Current assignee: Corning Inc
Priority date: 2015-03-06
Filing date: 2016-03-04
Publication date: 2020-08-21
Anticipated expiration: 2036-03-04
Also published as: KR20170118891A; WO2016144715A2; TW201641451A; TWI685473B; JP6761425B2; JP2018510115A; WO2016144715A3; CN107531535A; KR102509016B1

Abstract

An apparatus for bubbling gas into molten glass is disclosed. The bubbler may include a sleeve, a nozzle secured to one end of the sleeve, and a capillary member slidably disposed within the sleeve below the nozzle. The capillary element is connected to a positioning assembly configured to displace the capillary element within the sleeve.

Description

Apparatus and method for conditioning molten glass

This application claims priority from U.S. provisional application serial No. 62/129,210 filed 2015 03/06, in accordance with 35u.s.c. § 119, which is hereby incorporated by reference herein in its entirety.

Background

Technical Field

The present disclosure relates to apparatus for conditioning molten glass, and more particularly, to apparatus for injecting gas into molten glass (e.g., bubbling).

Technical Field

Commercial scale glass manufacturing is typically conducted in a refractory ceramic melting vessel, wherein raw materials (batch materials) are added to the melting vessel and heated to a temperature such that the batch materials undergo a chemical reaction to produce molten glass. Several methods may be used to heat the batch materials, including gas-fired burners and/or electric current.

Conditioning, e.g., fining and homogenizing, of the molten glass may be performed in certain portions of the melting vessel structure or in other vessels that are downstream of the melting vessel and connected to the melting vessel by conduits. In certain processes, bubbling gas into the molten glass can be used to stir the molten glass and improve its homogeneity, or to manipulate the redox state of batch components (e.g., fining agents).

Conventional bubblers typically employ ceramic tubes that are directly exposed, at least facing the high temperature, corrosive environment provided by the molten glass. Thus, the ceramic tube exhibits significant corrosion from the exposed surface. For hard glasses commonly used in the manufacture of optical articles (e.g., glasses used for display substrates), the common temperature range for molten glass in the melting vessel is about 1500-. The temperature of the molten glass in the fining vessel will be significantly higher and may approach 1700 ℃. In addition, the molten glass may freeze or condense, which may block the outlet of the channel and stop bubble formation or create crystalline phases that cannot be dissolved. There is also a possibility of defects and/or blockages occurring in the channels. In addition, supplying the bubble-generating gas can potentially leak at the bottom of the bubbler support between the platinum cladding and the support, thereby reducing gas pressure and reducing process stability. When such detrimental results occur, the bubbler must be replaced.

Bubblers are a viable and inexpensive solution to improve glass quality and potential glass fining. However, due to the noted problems at high temperature operation, improvements are needed to address the existing deficiencies.

Disclosure of Invention

Bubblers for bubbling gas into containers containing molten glass within a volume defined by the container have long been used, for example, to enhance glass melting. For example, the foaming process can increase natural convection during the melting process, thereby increasing the homogeneity of the molten glass and glass articles made therefrom. However, molten glass can be highly corrosive, and the combination of high temperatures and corrosive environments can severely damage conventional bubblers in a short period of time.

Thus, in one aspect, described herein is an apparatus for conditioning molten glass comprising a vessel comprising an interior volume. A bubbler extending into a volume of the container, the bubbler comprising: a sleeve including an internal passage extending therethrough, a nozzle secured with a first end of the sleeve, the nozzle including an internal passage extending between an inlet orifice and an outlet orifice, and a capillary element including a plurality of capillary passages extending therethrough. The sleeve and nozzle may comprise platinum. The capillary element is slidably engaged within the interior passage of the sleeve. The nozzle may include a recessed portion, wherein the recessed portion is located within the internal passage of the sleeve.

The apparatus may further comprise cooling means for cooling a portion of said apparatus. Furthermore, the screw element may be connected to a cooling device. The screw element may also be connected to the sleeve. However, the cooling apparatus does not provide direct cooling of the portion of the bubbler (the sleeve and nozzle) extending into the molten glass.

In an exemplary embodiment, the positioning assembly may be rotatably connected to the screw element and the capillary element may be connected to an air supply tube, which in turn is rotatably connected to the positioning assembly, such that rotation of the positioning assembly about the screw element causes displacement of the positioning device along the screw element. By having the supply tube rotatably connected to the positioning assembly and the capillary element connected to the gas supply tube, movement of the positioning assembly along the screw element causes the capillary element to move within the sleeve, thereby providing the ability to compensate for corrosion of the capillary element.

In order to limit the size of the bubbles generated by the bubbler, the nozzle may comprise a tapering outer profile in the direction towards the outlet orifice. The internal passage of the nozzle may also include an intermediate chamber, having a diameter greater than that of the outlet orifice, which serves as a location where gases supplied from the multiple passages of the capillary element meet.

The nozzle may be secured to the sleeve by a perimeter weld around a seam between the nozzle and the sleeve to prevent air pressure within the nozzle from separating the nozzle from the sleeve. Additionally or alternatively, the nozzle may be secured to the sleeve by welding a plurality of pins disposed about the outer periphery of the sleeve. Preferably, both seam welding (seam weld) and plug welding (plugweld) are used to secure the nozzle and sleeve.

At least a portion of the sleeve may comprise a ceramic coating, in particular the portion of the sleeve located within the cooling device. The ceramic coating helps to prevent the weld of the bushing from spreading to the inner wall of the cooling device if long term contact between the two occurs. Further, at least a portion of the cooling device may include a ceramic coating to prevent corrosion (e.g., oxidation) of the cooling device.

The apparatus may further comprise a sealing gasket located within the screw element between the capillary element and the screw element. The sealing gasket rests on the sealing lip in the internal passage of the screw element, and a fitting (e.g., a screw fitting) presses the sleeve against the sealing gasket via a flange on the sleeve. The gasket includes a passage through which the sleeve extends, and the gasket also seals around the sleeve to prevent gas leakage (e.g., atmospheric air through the passage of the screw element and atmospheric air in the gap between the sleeve and the capillary element into the molten glass, or vice versa).

The vessel may be a melting vessel, a fining vessel or a cooling vessel. The container may also be any one or more of the connecting conduits.

The output orifice of the nozzle includes an orifice region that is a cross-sectional area of the orifice in a plane perpendicular to a central axis of the nozzle, and each capillary passage of the plurality of capillary passages includes an output orifice having an orifice region. The sum of the aperture areas of the plurality of capillary passages may be substantially equal to the aperture area of the output aperture of the nozzle. Thus, the volumetric flow rate of gas from the outlet orifice of the nozzle substantially matches the volumetric flow rate of gas from the capillary element.

In another aspect, an apparatus for conditioning molten glass is disclosed that includes a vessel comprising an interior volume and a bubbler extending into the volume. The bubbler includes: a sleeve including an internal passage extending therethrough, a nozzle secured with a first end of the sleeve, and a capillary element including a plurality of passages extending through the capillary element, the plurality of passages being substantially parallel to a central longitudinal axis of the capillary element. The sleeve and nozzle may comprise platinum. The capillary element is slidably engaged within the interior passage of the sleeve. The screw element may be coupled to the sleeve, and the positioning assembly may be rotatably engaged with the screw element and configured such that rotation of the positioning assembly about the screw element displaces the capillary element within the sleeve.

The apparatus may further comprise a cooling apparatus associated with the screw element. The gas supply tube may be rotatably connected to the positioning assembly and further connected to the capillary element.

The vessel may be a melting vessel, a fining vessel or a cooling vessel. Additionally or alternatively, the container may be a connecting pipe.

In another aspect, a method of conditioning molten glass is disclosed, comprising: the molten glass is caused to flow into or out of a vessel that includes a bubbler extending into the molten glass and including an outlet orifice. The bubbler includes a sleeve, a nozzle, and a capillary element slidably disposed within the sleeve. The method may further include pressurizing the nozzle with a gas supplied through the capillary element, the gas having a pressure sufficient to prevent molten glass from entering the nozzle and contacting the capillary element.

The rate of bubbles released from the nozzle may be 0 bubbles per minute over a period of at least one hour. The rate of bubbles released from the nozzle may be 1-100 bubbles per minute.

The temperature range of the molten glass may be about 1550-.

The method can further include depressurizing the nozzle after pressurizing the nozzle such that the molten glass enters the nozzle, and then repressurizing the nozzle to force the molten glass out of the nozzle.

It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an overview or framework for understanding the nature and character of the embodiments as they are described and claimed. The accompanying drawings are included to provide a further understanding of the embodiments, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments herein and together with the description serve to explain the principles and operations thereof.

Drawings

FIG. 1 is a schematic view of an exemplary glass manufacturing apparatus according to the present disclosure;

FIG. 2 is a simplified cross-sectional view of a bubbler according to one embodiment of the present disclosure;

FIG. 3 is a cross-sectional perspective view of a portion of the bubbler of FIG. 2 showing a nozzle secured to an end of a sleeve and a capillary element slidably disposed within the sleeve;

FIG. 4 is a cross-sectional view of the nozzle of FIG. 4 in a plane parallel to the central longitudinal axis of the nozzle;

FIG. 5A is a cross-sectional view of the sleeve, nozzle and capillary element of FIG. 4, and including a cooling device;

FIG. 5B is a close-up view of a portion of FIG. 5A showing a coating applied to the outer surface of the sleeve;

FIG. 6 is a perspective view of an exemplary cooling apparatus according to an embodiment of the present disclosure, shown without a sleeve or nozzle installed;

FIG. 7 is a perspective view of a portion of the cooling device of FIG. 6, shown with the sleeve and nozzle installed;

FIG. 8A is a partial (top) cross-sectional view of the screw element coupled to a portion of the sleeve and cooling device and showing the sealing gasket sealing the capillary element;

FIG. 8B is a partial (bottom) cross-sectional view of the screw element of FIG. 8A, showing the capillary element connected to a gas supply tube;

FIG. 9 is a perspective view of the bushing of FIG. 8A, showing flanges for connecting the bushing and the screw element;

FIG. 10A is a partial (top) perspective view of an exemplary positioning assembly coupled to the screw element of FIGS. 8A and 8B, in accordance with an embodiment of the present disclosure;

FIG. 10B is a partial (bottom) perspective view of the positioning assembly of FIG. 10A, showing the connection between the gas supply tube and the gas line;

FIG. 11 is a schematic view of another glass manufacturing apparatus according to an embodiment of the present disclosure, wherein the glass manufacturing apparatus includes a downstream glass manufacturing apparatus including a molten glass conditioning vessel positioned between a melting vessel and a fining vessel, wherein the molten glass conditioning vessel includes a bubbler according to an embodiment of the present disclosure; and

FIG. 12 is a schematic view of another glass manufacturing apparatus in accordance with embodiments of the present disclosure in which a bubbler as disclosed herein may be placed in a fining vessel downstream of a melting vessel.

Detailed Description

The apparatus and method will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Unless otherwise noted, the images of the drawings may not be to scale, or between drawings.

Ranges can be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

Directional terminology used herein, such as upper, lower, left, right, front, rear, top, bottom, is for reference only to the accompanying drawings and is not intended to be absolute.

Unless otherwise stated, it is not intended that any method described herein be construed as requiring that its steps be performed in a particular order. Thus, where a method claim does not actually recite an order to be followed by its steps or it does not otherwise specifically imply that the steps are to be limited to a specific order in the claims or specification, it is not intended that any particular order be implied. The same applies to any possible explicative basis not explicitly stated, including: logic related to the set-up steps or operational flow; general meaning derived from grammatical structures or punctuation; number or kind of embodiments described in the specification.

As used herein, the terms "substantially", "essentially" and variations thereof are intended to mean that the features described are equal or approximately the same as the numerical values or descriptions.

Although the transition term "comprising" may be used to disclose various features, elements or steps of a particular embodiment, it should be understood that this implies that alternative embodiments may be included which may be described using the transition term consisting of, or consisting essentially of. Thus, implicit alternative embodiments to a device comprising a + B + C may include embodiments where the device consists of a + B + C and embodiments where the device consists essentially of a + B + C.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component" includes aspects having two or more such components, unless the context clearly indicates otherwise.

Aspects of the present disclosure include apparatus for conditioning batch materials into molten glass, and more particularly, apparatus for conditioning molten glass. The furnace of the present disclosure can provide a wide range of applications for heating gases, liquids, and/or solids. In one example, the apparatus of the present disclosure is described with reference to a glass melting system configured to melt batch materials into molten glass and deliver the molten glass to downstream processing equipment.

The methods of the present disclosure can condition molten glass in various ways. For example, the molten glass can be conditioned by heating the molten glass to a temperature above the initial temperature (e.g., greater than the melting vessel temperature). In another example, the molten glass may be conditioned by: the cooling rate of the molten glass is controlled by maintaining the temperature of the molten glass or by reducing the rate of heat loss through the input of thermal energy to the molten glass, which may otherwise occur.

The methods of the present disclosure may condition molten glass in a fining vessel, a mixing vessel, or other vessel. Optionally, the device may include one or more other components, such as: thermal management devices, electronic devices, electromechanical devices, support structures, or other components to facilitate operation of a glass manufacturing apparatus that includes a transfer vessel (conduit) that transfers molten glass from one location to another.

Shown in fig. 1 is an exemplary glass manufacturing apparatus 10. In some examples, glass manufacturing apparatus 10 may include a glass melting furnace 12, which may include a melting vessel 14. In addition to melting vessel 14, glass melting furnace 12 may optionally include one or more other components, such as heating elements (e.g., burners or electrodes) configured to heat and convert batch materials into molten glass. In other examples, glass melting furnace 12 may include a thermal management device (e.g., an insulation assembly) configured to reduce heat loss from the vicinity of the melting vessel. In other examples, glass melting furnace 12 may include electronic and/or electromechanical devices configured to facilitate melting of the batch materials into a glass melt. In addition, glass melting furnace 12 can include support structures (e.g., support pans, support members, etc.) or other components.

The glass melting vessel 14 typically comprises a refractory material, such as a refractory ceramic material. In some examples, the glass melting vessel 14 may be constructed from refractory ceramic bricks (e.g., refractory ceramic bricks comprising alumina or zirconia). The glass container 14 may also include one or more bubblers 16. The bubbler 16 may be placed in the floor of the melting vessel and extend upwardly into the molten glass occupying the volume of the melting vessel. In other embodiments, for example, for other containers, the bubblers may be placed in other orientations. Bubbler 16 may be configured to introduce a gas into the molten glass, such as, but not limited to, oxygen, nitrogen, helium, argon, carbon dioxide, and mixtures thereof. The bubbler 16 may be placed near the inlet region of the melting vessel, near the outlet region of the melting vessel, or in an intermediate position within the melting vessel.

In some examples, the glass melting furnace may be integrated as a component of a glass manufacturing apparatus configured to manufacture a glass ribbon. In some examples, the glass melting furnace of the present disclosure may be incorporated as a component of a glass manufacturing apparatus including a slot draw apparatus, a float bath apparatus, a down-draw apparatus, an up-draw apparatus, a press roll apparatus, or other glass ribbon manufacturing apparatus. For example, FIG. 1 schematically shows a glass melting furnace 12 as a component of a fusion downdraw glass manufacturing apparatus 10 for fusion drawing a glass ribbon for subsequent processing into glass sheets.

Glass manufacturing apparatus 10 (e.g., fusion downdraw apparatus 10 of fig. 1) can optionally include an upstream glass manufacturing apparatus 18 positioned upstream relative to glass melting vessel 14. In some examples, a portion or the entire upstream glass manufacturing apparatus 18 can be incorporated as a component of glass melting furnace 12.

As shown in the illustrative example, the upstream glass manufacturing apparatus 18 can include a storage bin 20, a batch material delivery device 22, and a motor 24 connected to the batch material delivery device. Storage bins 20 may be configured to store a quantity of batch material 26 that may be fed into melting vessel 14 of glass melting furnace 12, as indicated by arrow 28. In some examples, the batch material delivery device 22 may be powered by a motor 24 configured to deliver a predetermined amount of batch material 26 from the storage bin 20 to the melting vessel 14. In other examples, motor 24 may power batch delivery device 22 to introduce batch material 26 at a controlled rate based on the sensed level of molten glass downstream of melting vessel 14. Thereafter, the batch material 26 within the melting vessel 14 can be heated to form molten glass 30.

The glass manufacturing apparatus 10 can also optionally include a downstream glass manufacturing apparatus 32 positioned downstream relative to the glass melting furnace 12. In some examples, a portion of downstream glass manufacturing apparatus 32 may be incorporated as a component of glass melting furnace 12. For example, first connecting conduit 34 or other portions of downstream glass manufacturing apparatus 32 described below may be incorporated as components of glass melting furnace 12. The components of the downstream glass manufacturing apparatus, including the first connecting conduit 34, may be formed from a precious metal. Suitable noble metals include platinum group metals selected from: platinum, iridium, rhodium, osmium, ruthenium, and palladium, or alloys thereof. For example, downstream components of the glass manufacturing apparatus may be formed from a platinum-rhodium alloy that includes 70-90 wt.% platinum and 10-30 wt.% rhodium.

Downstream glass manufacturing apparatus 32 may include a first conditioning vessel (e.g., fining vessel 36) located downstream from melting vessel 14 and connected to melting vessel 14 by way of first connecting conduit 34 as described above. In some examples, molten glass 30 may be gravity fed from melting vessel 14 to fining vessel 36 by way of first connecting conduit 34. For example, gravity may cause molten glass 30 to pass from melting vessel 14 to fining vessel 36 through the internal path of first connecting conduit 34.

Within fining vessel 36, bubbles can be removed from molten glass 30 by various techniques. For example, the batch material 26 may include one or more multivalent compounds (i.e., fining agents, such as tin oxide) that, when heated, undergo a chemical reduction reaction and release oxygen. Other suitable fining agents include, but are not limited to, arsenic, antimony, iron, and cerium. The temperature of fining vessel 36 may be heated to a temperature greater than the temperature of melting vessel 14 to further heat the fining agent. Oxygen bubbles generated via temperature-induced chemical reduction of the fining agent rise through the molten glass within the fining vessel, wherein gases in the molten glass generated in the furnace may be incorporated into the oxygen bubbles generated by the fining agent. The expanded bubbles can then rise to the free surface of the molten glass in the fining vessel and then exit through a suitable discharge tube.

The downstream glass manufacturing apparatus 32 may also include a second conditioning vessel (e.g., mixing vessel 38), which may be located downstream of the fining vessel 36. Mixing vessel 38 can be used to provide a uniform glass melt composition to reduce or eliminate non-uniformity lines (cord) that might otherwise be present in the molten glass. As shown, fining vessel 36 may be connected to molten glass mixing vessel 38 by way of a second connecting conduit 40. In some examples, molten glass 30 may be gravity fed from fining vessel 36 to mixing vessel 38 by way of second connecting conduit 40. For example, gravity may cause molten glass 30 to pass from fining vessel 36 to mixing vessel 38 through the internal path of second connecting conduit 40. In some examples, the downstream glass manufacturing apparatus 32 may include a plurality of mixing vessels. For example, in some embodiments, a mixing vessel may be included that is upstream of the fining vessel 36 and a second mixing vessel (which is downstream of the fining vessel 36). In some embodiments, mixing may be performed by a mixing device (e.g., a static mixing blade). The static mixing blades can be placed in a conduit of a downstream glass manufacturing apparatus, or in other vessels of the downstream glass manufacturing apparatus.

The downstream glass manufacturing apparatus 32 may also include other conditioning vessels, such as a delivery vessel 42, which may be located downstream of the mixing vessel 38. The delivery vessel 42 can condition the molten glass 30 to be fed into the downstream forming device. For example, the delivery vessel 42 can act as a hopper and/or flow controller to regulate and provide a consistent flow of molten glass 30 to the forming body 44 by way of the delivery conduit 46. As shown, the mixing vessel 38 may be connected to the transfer vessel 42 by way of a third connecting conduit 48. In some examples, molten glass 30 may be gravity fed from mixing vessel 38 to delivery vessel 42 by way of third connecting conduit 48. For example, gravity may function to drive molten glass 30 from mixing vessel 38 to delivery vessel 42 through the internal path of third connecting conduit 48.

Downstream glass manufacturing apparatus 32 may also include a forming apparatus 50 that includes forming body 44 as described above, which includes an inlet conduit 52. The delivery conduit 46 can be positioned to deliver the molten glass 30 from the delivery vessel 42 to an inlet conduit 50 of a forming apparatus 50. In the fusion forming process, forming body 44 may include a groove 54 formed in an upper surface of the forming body, and converging forming surfaces 58 that converge along a bottom edge (root) 58 of the forming body. Molten glass delivered to the forming body trough via delivery vessel 42, delivery conduit 46, and inlet conduit 52 overflows the walls of the trough and flows down the converging forming surfaces as separate streams of molten glass. The separate flows of molten glass join below the root and produce a single ribbon of glass 60 along the root, which is drawn from the root 58 by applying tension to the ribbon (e.g., by gravity and pulling rolls (not shown)) to control the size of the ribbon, such that the ribbon 60 undergoes a viscoelastic transition and has mechanical properties that provide the ribbon 60 with stable dimensional characteristics as the glass cools and increases in viscosity. The ribbon may then be separated into individual glass sheets by a glass separation device (not shown).

Unlike other components of the downstream glass manufacturing apparatus, forming body 44 is typically formed from a refractory ceramic material, such as alumina (aluminum oxide) or zirconia (zirconium oxide), although other refractory materials may also be used. In some examples, the forming body 44 is a monolithic block of ceramic material that is isostatically pressed and sintered, and then machined to a suitable shape. In other examples, the shaped body may be formed by joining two or more blocks of refractory material (e.g., refractory ceramic material) together. The forming body 44 can include one or more precious metal components configured to direct a flow of molten glass from and over the forming body.

As shown in fig. 2, which is a simplified schematic diagram of an exemplary bubbler 16 according to embodiments described herein, the bubbler 16 comprises a capillary element 100, a sleeve 102 and a nozzle 104. Capillary element 100, sleeve 102, and nozzle 104 may collectively define a central flow longitudinal axis 105, which may define a common central axis for the apparatus and selected components. The bubbler 16 may further include: a cooling device 106, a screw element 108, a positioning assembly 110, and a support element 111 configured to support the bubbler 16 and secure the bubbler to a suitable structure (e.g., a steel beam or other building structure). In the following description, other components of the exemplary bubbler are presented in greater detail.

Fig. 3 and 4 are respectively: i) a cross-sectional perspective view of the end of bubbler 16; and ii) a longitudinal cross-sectional view of nozzle 104, showing capillary element 100, sleeve 102 and nozzle 104. Specifically, the bushing and/or nozzle shown in fig. 3 and 4 is configured to be inserted into molten glass 30. For example, capillary element 100 may be formed from any refractory ceramic suitable for use in high temperature corrosive environments. In some examples, capillary element 100 may be formed from aluminum oxide (e.g., alumina sand, or corundum) or stabilized zirconia (e.g., alumina sand, or corundum)Exemplary yttria-stabilized, calcium-stabilized, or magnesium-stabilized zirconia). For example, the capillary element 100 may be selected to be compatible with the glass composition being manufactured so that any dissolution or corrosion of the capillary element that may occur does not significantly affect the overall glass composition. Capillary element 100 also includes a plurality of capillary channels 112 that extend from one end (i.e., first end 114) of capillary element 100 to an opposite end (see fig. 8B, second end 176) of the capillary element, with capillary channels 112 being substantially parallel to central axis 105. Each capillary passage 112 is configured to restrict molten glass from entering the capillary passage if the molten glass reaches the capillary element, and each capillary passage may have a diameter of about 0.02-0.635 mm. The term "diameter" as used herein refers to the largest dimension in an axis of the channel perpendicular to the central axis 105, and is not strictly limited to channels of circular cross-sectional shape. For example, the capillary channel 112 can be circular, rectangular, or include other geometric shapes. Each capillary passage 122 includes an aperture 115 at the first end 114, and each capillary aperture 115 includes an area calculated from the size of the capillary aperture. For example, if the capillary hole is a circular hole, the area of the capillary hole is the area of the circle π r²Where r is the radius of the circle.

Capillary element 100 is slidably mounted within sleeve 102 such that capillary element 100 may be displaced within sleeve 102 along central axis 105 as desired. The sleeve 102 may be formed of any metal capable of withstanding the high temperatures and corrosive environments associated with glass melting or molten glass conditioning. For example, suitable metals include platinum group metals, osmium, palladium, ruthenium, iridium, rhodium, platinum, or alloys thereof. In some examples, the sleeve 102 may be formed from a platinum-rhodium alloy containing about 70-90% platinum and about 10-30% rhodium.

Similar to sleeve 102, nozzle 104 may be formed from any metal capable of withstanding the high temperatures and corrosive environments associated with glass melting or molten glass conditioning. For example, suitable metals include platinum group metals, osmium, palladium, ruthenium, iridium, rhodium, platinum, or alloys thereof. In some examples, nozzle 104 may be formed from a platinum-rhodium alloy that contains about 70-90% platinum and about 10-30% rhodium.

Nozzle 104 includes a passageway 116 extending from a first bore 120 defined by a first end 122 to a second bore 124 defined by a second end 126. In some embodiments, the diameter of the second bore 124 is greater than the diameter of the first bore 120. The area of the first apertures 120 in a plane perpendicular to the central axis 105 may be substantially equal to the cumulative area of the total number of capillary passage apertures 115 to prevent restriction of gas flow exiting the bubbler through the first apertures 120. That is, for a given volume of gas exiting the capillary element 100, the size of the first aperture 120 may be selected to exhibit a similar or the same flow regime for the gas as the capillary element. As used herein, the aperture area is the total area of the apertures in a plane perpendicular to the central axis 105. For example, if the capillary holes have a uniform circular cross-section and the total number of capillary passages 112 is 20, the cumulative area of the holes is 20 π r²(assuming each channel has a uniform radius), therefore, the area of the first hole 120 is chosen to be substantially equal to π r². By "substantially" is meant that the area of the first aperture 120 is within 10%, such as within 5% or within 1% of the cumulative area of the capillary passage.

The nozzle 104 may also include a tapered outer surface 128 that tapers in a direction toward the first aperture 120 to limit bubble size during bubble generation. As best shown in fig. 4, the nozzle 104 may include a tapered cross-sectional outer surface profile in a plane parallel to a central longitudinal axis 105 of the nozzle. For example, the outer surface 128 may include a tapered profile. In other examples, such as the example shown in fig. 4, the outer surface profile may include an arcuate outer surface profile, such as an S-shape. In other words, a radius R1 of at least a portion of the nozzle between the central axis 105 and the outer surface 128 in a direction from the second end 126 to the first end 122 may decrease. The passage 116 may include a first passage 130 and a second passage 132 in fluid communication with the first passage 130, wherein the first passage 130 may also terminate at the first aperture 120 and the second passage 132 may terminate at the second aperture 124. In an exemplary embodiment, the second channel 123 may include a diameter that is larger than a diameter of the first channel 130. In some embodiments, the first channel 130 may have a substantially constant cross-sectional dimension (e.g., diameter). In some embodiments, the channel 116 may include a taper, e.g., in the direction from the second aperture 124 to the first channel 130, within the second channel 132, such that the size of the second aperture 124 matches the size of the first channel 130. For example, the second channel 132 may include a tapered profile. The first passage 130 may be cylindrical.

At least a portion of the outer surface of nozzle 104 is recessed by an amount such that the outer diameter of recessed surface 134 is disposed within the inner diameter of first end 136 of sleeve 102. For example, the nozzle 104 of the lower portion may be recessed. Thereafter, shoulder 138 of nozzle 104 may be welded to first end 136 of sleeve 102 along a seam 140 where shoulder 138 meets first end 136. In an exemplary embodiment, the casing 102 may also include plug welds 142 around the casing perimeter, for example at 180 or 90 degree intervals, wherein a hole is drilled through the casing 102 to the recessed surface 134, and additional welds may be made by filling the drilled hole with weld metal. For example, the plug weld may be made of a metal that is compatible with the sleeve and nozzle materials. In some examples, the plug weld 142 may be formed from a platinum-rhodium alloy containing about 70-90% platinum and about 10-30% rhodium.

As described above, capillary element 100 is slidably disposed within the longitudinally extending passage within sleeve 102 and may be arranged such that first end 114 of capillary element 100 is adjacent second end 126 of nozzle 104. The second channel 132 is sized such that each of the plurality of capillary channels 112 opens into the second channel 132. Thus, the second passage 132 may form an intermediate chamber for receiving the airflow from the capillary element 100, after which the airflow enters the first passage 130 and then exits the nozzle 104 through the first aperture 120.

As shown in fig. 2, 5A, 5B, and 6-7, the bubbler 16 may further include a cooling device 106. The cooling device 106 may be a fluid cooling device, wherein a cooling fluid (e.g., water) flows through channels within the cooling device. The cooling device 106 may include an inlet 144 and an outlet 146 through which cooling fluid is supplied to and recovered from the cooling device 106, respectively, as indicated by arrows 148. The cooling device 106 may include ears 150 located on and extending from the outer wall of the cooling device to control the insertion depth of the bubbler into the container. The cooling device 106 may also include an inner wall 152 defining a central passage through which the sleeve 102 and the capillary element 100 extend. In the perspective view of FIG. 6, the cooling apparatus 106 is shown without the sleeve 102 and nozzle 104, and in the perspective view of FIG. 7, the upper portion of the cooling apparatus 106 is shown with the sleeve 102 and nozzle 104 in place. The sleeve 102 may be secured to the cooling device 106 at an upper end of the cooling device 106, such as by a weld 154 between the sleeve 102 and the cooling device 106, such that a portion of the sleeve 102 extends out from a top of the cooling device 106.

The cooling device 106 may be formed of a high temperature steel (e.g., a suitable stainless steel) and the upper portion 156 of the cooling device 106 (typically above the ears 150) may be coated with a refractory coating 158 (e.g., a plasma sprayed zirconia coating) to protect the portion of the cooling device closest to the vessel (e.g., the melt vessel 14) from oxidation. In addition, the portion of the sleeve 102 that is within the cooling apparatus 106 and extends through its central passage (e.g., length 157 as shown in FIG. 5A) may also be coated with a ceramic coating 159 (see FIG. 5B, e.g., plasma sprayed zirconia) to prevent the weld of the sleeve from propagating to the inner wall 152 if the inner wall is in contact with the sleeve for a sufficiently long time.

As best shown in fig. 5A, at least a portion of the sleeve 102 extends above the cooling device 106 and is not directly cooled by the cooling device. That is, the portion of bubbler 16 extending into the molten glass (and particularly the upper portion of sleeve 102) is not surrounded by the cooling apparatus. Thus, nozzle 104, a portion (upper portion) of sleeve 102 and a portion of capillary element 100 are not cooled by cooling device 106.

Referring now to fig. 8A, 8B and 9, where fig. 8B is a continuation of fig. 8A in a downward direction, the sleeve 102 may include a flange 160 extending from a second end (bottom end) 162 of the sleeve 102. The fitting 164 may be used to secure the sleeve 102 within the channel 166 of the screw element 108 via the flange 160, wherein the flange 160 is forced against one or more sealing gaskets 172, which sealing gaskets 172 are located within and extend into the channel 166. The channel 166 extends completely through the screw element 108, i.e., from the first end 174 to the second end 176 (see fig. 8B). For example, the fitting 164 may be a threaded fitting threaded into the first end 174 of the channel 166. Accordingly, the passage 166 may include threads within a first portion of the passage 166 that mate with the threaded fitting 164. Pressing the one or more sealing gaskets 172 through the fitting 164 forces the one or more sealing gaskets 172 against the capillary element 100 and the sealing lip 173, thereby sealing the screw element 108 against gas flow between the screw element and the capillary element. After assembly, the inner wall 152 of the cooling device 106 may be secured with the fitting 164 by a weld 178. Thus, the screw element 108 may be firmly connected to the cooling device 106.

As best shown in FIG. 8B, showing the bottom end of the screw element 108, the second end 179 of the capillary element 100 is connected to the first end 180 of the gas supply tube 182 via a connector 184. The connection 184 may be an airtight connection. The gas supply pipe 182 may be, for example, a stainless steel pipe containing a central passage 186. The connection 184 includes a passage 188 that allows gas to flow between the gas supply tube 182 and the capillary element 100. As shown in fig. 8B and 10A, the bearing housing 190 is engaged with the screw element 108 via threads 192 and mating threads in a passage of the bearing housing 190 through which the screw element 108 extends. The bearing block 190 forms a part of the positioning assembly 110. To prevent binding and galling and to promote smooth thread engagement, the bearing housing 190 may be formed of a corrosion resistant metal that is softer than the wall screw member 108. For example, the bearing seat 190 may be formed of silicon bronze and the threads 192 may be trapezoidal threads, such as Acme threads.

Fig. 10B is a perspective view of the positioning assembly 110, and is a continuation of fig. 10A in a downward direction, wherein the bearing housing 190 is engaged with and rotatable about the screw member 108. In addition, the positioning assembly 110 may include an outer sleeve 196 coupled to the bearing housing 190. Fig. 10B shows the (bottom) end of the outer sleeve 196. The outer housing 196 includes a bearing assembly 198 attached to the outer housing 196 and a sleeve (collar)200 attached to the bearing assembly 198. The gas supply tube 182 extends through the bearing assembly 198 and the sleeve 200, and the sleeve 200 may be coupled to the gas supply tube 182 by suitable fasteners, such as nuts 202. Thus, the air supply pipe 182 is rotatably coupled to the positioning assembly 110. The gas supply tube 182 is also connected to a gas line 204 by suitable connections and fittings, wherein the gas line 204 is in fluid communication with a gas source 206.

As can be readily observed from the above description and the accompanying drawings, the gas line 204 is in direct fluid communication with the nozzle 104 via the gas supply tube 182, the connector 184 and the capillary element 100. It should also be noted that with the cooling apparatus 106 engaged with the glass melting furnace 12, the gas supply pipe 182 is rotatably coupled to the outer casing 196 via the bearing assembly 192 and the bushing 200 (so that the positioning assembly 110 is rotatable about the gas supply pipe 182) such that rotation of the positioning assembly 110 (including the bearing housing 190 and the outer casing 196) about the screw member 108 causes displacement of the positioning assembly 110 on the screw member 108. As positioning assembly 110 is displaced on screw element 108, capillary element 100 also moves within sleeve 102, rising or falling depending on the direction of rotation of the positioning assembly.

The positioning assembly 110 may be rotated manually (e.g., by hand), or the positioning assembly 110 may be engaged with a drive device (not shown) to rotate the positioning assembly. For example, the drive means may comprise a worm drive, wherein one of the bearing housing 190 or other portion of the positioning assembly 110 is engaged with a worm gear that is connected to a worm screw connected to a motor. The drive means may be activated manually or a control system (not shown) may be employed to activate the drive means at predetermined times.

In operation, gas is delivered under pressure from the gas source 206 to the bubbler 16, and the gas pressure within the nozzle channel 116 is maintained at a pressure slightly greater than the pressure imparted by the molten glass on the bubbler. The pressure required will depend on such variables as the density of the molten glass 30 and the depth of the molten glass above the bubbler first (output) orifice 120. The gas pressure can be controlled, for example, by a valve 208 (e.g., a needle valve) and a flow meter 210 (see fig. 1) at a pressure suitable for releasing 0-100 bubbles per minute from the bubbler 16 into the molten glass 30. Advantageously, the bubbler 16 can withstand significant periods of time in which the gas pressure may drop below the appropriate pressure required for bubbling due to intentional deactivation of the bubbler (e.g., shutting off the gas supply) or unintentional conditions such as line failure. Under ideal conditions where bubbling is not desired, the pressure within the first channel 116 may be maintained at a pressure equal to that imparted by the depth of molten glass above the bubbler 16. At this equilibrium condition, the bubble rate would be 0 bubbles per minute. Molten glass does not enter through the channel 116 and does not contact the capillary element 100. On the other hand, in the case where the gas supplied to the bubbler 16 falls below the pressure that prevents molten glass from entering the passage 116, and where the passage 116 may be filled with molten glass that may contact the capillary element 100. However, because the upper portion of bubbler 16 (e.g., nozzle 104) is not cooled, the molten glass within the nozzle (i.e., channel 116) remains fluid. If the gas pressure within the system, and in particular within capillary element 100, is restored to a level greater than the pressure imparted by the molten glass above the bubbler, the molten glass may be forced out of channel 116 (or capillary channel 112) and bubbling may resume, or the bubbler may return to an ideal state such that nozzle 104 is pressurized but the bubbling rate is substantially zero. If the molten glass has been in contact with capillary element 100 for a time sufficient to cause degradation of capillary element 100, the capillary element may be lifted within sleeve 102 by positioning assembly 110. Thus, the bubbler 16 provides the ability to terminate bubbling, either intentionally or unintentionally, for an indefinite period of time and then restart bubbling when needed without the need to remove the bubbler and rebuild the bubbler.

Conventional bubblers that rely on cooling to protect the bubbler assembly exposed to the molten glass may not be able to clean the glass-filled channel. If molten glass enters the channels of the bubbler, the glass may cool to a low viscosity, interfering with the ability to force the glass out of the channels. Shutting down the cooling to achieve a viscosity reduction of the glass has the risk of damaging the bubbler structure intended to be protected by cooling. Therefore, it is common practice to replace the bubbler.

Another example of a glass manufacturing apparatus 10 is shown in fig. 11, wherein the glass manufacturing apparatus includes a downstream glass manufacturing apparatus 32 and may further include a molten glass conditioning vessel 212 located between the melting vessel 14 and the fining vessel 36 and in fluid communication with the melting vessel 14 via a conduit 214, wherein the molten glass conditioning vessel includes one or more bubblers 16 according to embodiments of the present disclosure. Conditioning vessel 212 may consist of, for example, a cooling vessel in which the molten glass from melting vessel 14 is cooled to a temperature below the melting temperature to effect a change in the redox state of one or more fining agents within the molten glass. Thus, the fining agent may be "recharged" by the oxygen provided by the one or more bubblers 16 prior to entering the fining vessel 36. The conditioning vessel 212 may be a supplemental melting vessel, for example, a melting vessel having multiple temperature zones. Alternatively or optionally, the fining vessel 36 may include one or more bubblers 16.

FIG. 12 shows a partial schematic view of another glass manufacturing apparatus 300 that includes a melting vessel 302, the melting vessel 302 including a melting section 304 and a fining section 306 separated by a wall 308 (which has one or more channels therethrough). A bubbler 16 may be included in the melt section 304. Alternatively or optionally, the clarification section 306 may include one or more bubblers 16.

It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments herein without departing from the scope and spirit of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of this embodiment provided they come within the scope of the appended claims and their equivalents.

Claims

1. An apparatus for conditioning molten glass, the apparatus comprising:

a container comprising an interior volume, the container having a first end,

a bubbler extending into the volume, comprising:

a cannula including an internal passage extending therethrough;

a nozzle secured with the first end of the sleeve, the nozzle including an internal passage extending between an inlet aperture and an outlet aperture; and

a capillary element including a plurality of capillary channels extending therethrough, the capillary element being slidably mounted in the internal channel of the sleeve.

2. The apparatus of claim 1, further comprising a cooling apparatus.

3. The apparatus of claim 2, further comprising a screw element coupled to the cooling apparatus.

4. The apparatus of claim 1, further comprising a screw element coupled to the sleeve.

5. The apparatus of claim 4, further comprising a positioning assembly rotatably coupled to the screw element.

6. The apparatus of claim 5, wherein the capillary element is connected to a gas supply tube.

7. The apparatus according to claim 6, wherein the gas supply tube is rotatably connected to the positioning assembly.

8. The apparatus of claim 1, wherein the nozzle includes an outer profile that tapers in a direction toward the outlet orifice.

9. The apparatus of claim 3, wherein the internal passage of the nozzle comprises an intermediate chamber having a diameter greater than a diameter of the exit orifice.

10. The apparatus of claim 1, wherein the nozzle is secured to the sleeve by a perimeter weld around a seam between the nozzle and the sleeve.

11. The apparatus of claim 10, wherein the nozzle is secured to the sleeve by a plurality of pin welds.

12. The apparatus of claim 1, wherein at least a portion of the sleeve comprises a ceramic coating.

13. The apparatus of claim 2, wherein at least a portion of the cooling apparatus comprises a ceramic coating.

14. The apparatus of claim 3, wherein a sealing gasket is disposed between said capillary element and said screw element.

15. The apparatus of claim 1, wherein the nozzle comprises a recessed portion disposed within the internal passage of the sleeve.

16. The apparatus of claim 1, wherein the vessel is a melting vessel, a fining vessel, or a cooling vessel.

17. The apparatus of claim 1, wherein the sleeve and the nozzle comprise platinum.

18. The apparatus of claim 1, wherein the outlet orifice of the nozzle comprises an orifice area and each of the plurality of capillary passages comprises an outlet orifice having an orifice area, wherein a sum of the orifice areas of the plurality of capillary passages is equal to the orifice area of the outlet orifice of the nozzle.

19. An apparatus for conditioning molten glass, the apparatus comprising:

a container comprising an interior volume, the container having a first end,

a bubbler extending into the volume, comprising:

a cannula including an internal passage extending therethrough;

a nozzle secured to the first end of the sleeve;

a capillary element including a plurality of passages extending therethrough, the capillary element slidably mounted in the internal passage of the sleeve;

a screw element connected to the sleeve; and

a positioning assembly rotatably engaged with the screw element and configured such that rotation of the positioning assembly about the screw element displaces the capillary element within the sleeve.

20. The apparatus of claim 19, further comprising a cooling apparatus coupled to said screw element.

21. The apparatus of claim 20, further comprising a gas supply tube coupled to the positioning assembly and further coupled to the capillary element.

22. The apparatus of claim 19, wherein the vessel is a melting vessel, a fining vessel, or a cooling vessel.

23. The apparatus of claim 19, wherein the sleeve and the nozzle comprise platinum.

24. A method of conditioning molten glass, the method comprising:

flowing molten glass into or out of a vessel, the vessel comprising a bubbler extending into the molten glass and comprising an outlet orifice, the bubbler comprising a sleeve, a nozzle, and a capillary element slidably disposed within the sleeve; and

pressurizing the nozzle with a gas supplied through the capillary element, the gas having a pressure sufficient to prevent the molten glass from entering the nozzle and contacting the capillary element.

25. The method of claim 24, wherein the rate of release of bubbles from the nozzle is 0 bubbles per minute over a period of at least one hour.

26. The method of claim 24, wherein the rate of bubble release from the nozzle is 1-100 bubbles per minute.

27. The method of claim 24, wherein the temperature of the molten glass is 1550-.

28. The method of claim 24, wherein after pressurizing the nozzle, depressurizing the nozzle such that the molten glass enters the nozzle, and then repressurizing the nozzle such that the molten glass is forced out of the nozzle.

29. The method of claim 24, wherein the capillary element includes a plurality of capillary channels extending therethrough.