KR20130090790A

KR20130090790A - Apparatus and method for controlling thickness of a flowing ribbon of molten glass

Info

Publication number: KR20130090790A
Application number: KR1020127033299A
Authority: KR
Inventors: 순규 이; 샨 알. 마크햄
Original assignee: 코닝 인코포레이티드
Priority date: 2010-05-26
Filing date: 2011-05-23
Publication date: 2013-08-14
Also published as: CN102906036A; KR101959697B1; TWI530463B; JP5974145B2; TW201141796A; WO2011149800A3; WO2011149800A2; JP5778761B2; JP2015214487A; JP2013528148A; CN102906036B; KR20180041256A; KR101850164B1

Abstract

In forming the sheet material from the molten glass, the heat sink is placed in the forming area to absorb thermal energy from a separate local portion of the molten glass located proximate to the draw line or root, thereby reducing the local thickness change of the sheet. By controlling, it provides a uniform glass sheet thickness over the sheet width. The heat sink may be disposed in a fixture configured to rotate or pivot the heat sink (ie, the cooling member) about at least one axis, thereby allowing heat to be absorbed from the flowing molten glass. The heat sink may be inserted towards, or located away from, the flowing molten glass to change the amount of thermal energy extracted by the cooling member (and hence the thickness and viscosity of the localized area cooled by the cooling member). have. Cooling is achieved without directing the cooling gas towards the molten glass flowing from the cooling member.

Description

Apparatus and method for controlling the thickness of the flowing molten glass ribbon {APPARATUS AND METHOD FOR CONTROLLING THICKNESS OF A FLOWING RIBBON OF MOLTEN GLASS}

This application is a priority claim based on US Provisional Application No. 61 / 348,512, filed May 26, 2010. The contents of this application and the entire contents of publications, patents, and patent documents referred to herein are incorporated by reference.

The present invention relates to a method and apparatus for controlling the thickness of flowing molten glass, and more particularly to a method and apparatus for controlling the thickness of continuously flowing molten glass in a downdraw glass sheet forming process.

When the molten glass is drawn into the sheet molding, the glass may stretch or weaken from the thickness initially delivered to the final sheet thickness. In an overflowing underdraw process, the molten glass flows down along opposite converging sides of the forming member, exiting from the root or bottom edge of the root as a single ribbon of glass, the initial thickness of the glass ribbon being the bottom of the forming member. Measured close to the edge, wherein the lower edge of the forming member exhibits a draw line in such an operation. The single sheets of glass are then separated from the free end of the drawn ribbon.

Obtaining a uniform thickness of the ribbon has a problem in both the top and bottom drawing processes where the thickness characteristics of the final sheet are determined during the attenuation process by both the uniformity of the initial thickness and the uniformity of the glass viscosity. That is, the given thickness change of the final sheet may be due to inaccurate measurement, defects at the glass contact sides of the molded part, or due to imbalance in the temperature environment of the glass causing defects in the viscosity profile of the glass flowing towards the draw line. It may be.

The change in thickness of the glass sheet is a problem considered by the industry, inherent in the sheet drawing process, and can manifest itself in several common types of defects, such as wedges, long-term waveform changes, and short-term waveform changes. . The wedge is a total thickness change, in which the ribbon or sheet is thicker at one edge than the other edge. Long wave changes have a range of amplitudes and sizes that can be considered (eg, exceeding a few inches) and can be measured by measuring the ribbon along the passageway in a direction transverse to the drawing direction. Short wave changes have small amplitudes and pitches (eg, about 3 inches or less), and generally overlap with long wave changes.

As found, in order to make sheet glass free of distortion, it is necessary to compensate or minimize local temperature changes or fluctuations around the glass and within the area of the ribbon molded body. Such local temperature changes in the vicinity of the draw line cause a wave form or alternating thick and thin sections running longitudinally in the ribbon drawn in the vertical direction. The waveform or thickness change in the longitudinal direction, in turn, results in very inadequate distortion from the optical point of view, especially when the object is seen through glass that is acute with respect to the waveform.

Prior art methods of controlling such thickness variations include air flowing from the cooling tubes arrayed along the length of the shaped body towards the molten glass. The straight cooling tubes are arranged at equal intervals along the length of the body and are positioned so that the central longitudinal axis of each tube is perpendicular to the vertical plane passing through the loop. In addition, the cooling tubes are covered by an outer tubular shield. As such, the tubes are strictly positioned with respect to the shaped body and the flowing glass.

Unfortunately, the thickness defects of the glass ribbon may be unstable in positioning over long periods of time, or the lateral position of the ribbon itself may not be constant. In this way, the pre-located and fixed cooling tubes can be suitably positioned in the first, but in the second poorly positioned for effective control thickness due to defects or movement of the ribbon.

Another method is included using cooling tubes mounted in a fixture, wherein the fixture is provided for swinging the cooling tubes about one or more axes to extend the range of a single tube and improve the cooling effect from the flow of cooling gas. Makes it possible.

SUMMARY OF THE INVENTION The present invention is directed to an improved method and apparatus for substantially reducing the general type in which local thickness changes are identified as short wave changes with a width of less than a few inches.

In forming a glass sheet with molten glass, the heat sink is located in the forming area near the surface of the molten glass flowing to absorb thermal energy from separate local portions of the molten glass, in particular controlling the local thickness change of the sheet. And placed at a location near the draw line or root to provide a uniform glass thickness. The heat sink, or cooling member, is placed in a fixture configured to enable varying the provision of the cooling member to the flowing glass (and shaped body) by rotating or pivoting the heat sink (ie, cooling member) about at least one axis. Can be. This makes it easy to remove heat from the flowing molten glass and to change the magnitude of this heat removal based on the downstream properties of the glass, for example thickness. The cooling member is inserted towards each flowing molten glass or positioned backward from the glass to change the calorie energy extracted by the cooling member (and the viscosity and thickness of the localized region cooled by the cooling member). Or the cooling member may be rotated or pivoted about an axis. Cooling is achieved without the need for a conventional local cooling method of guiding the cooling gas towards the molten glass flowing from the cooling member.

In accordance with an embodiment of the present invention, an apparatus is disclosed for forming a continuous ribbon of molten glass in a process of making a bottom draw glass, the apparatus comprising a shaped body comprising a converging forming surface for converging into a root, the shaped body being disposed around the shaped body. A seal, at least one thickness control unit coupled to the seal and for varying the local temperature of the molten glass, wherein the thickness control unit includes a long cooling member extending proximate to the molten glass flowing on the molded body. Including; And the thickness control unit does not include a mechanism in which an air flow is supplied through the cooling member (ie, the air flow does not face the molten glass from the cooling member). The cooling member is preferably rotatable about a vertical axis, which means that the cooling tube can be pivoted or swinged about the vertical axis to change the angular orientation of the cooling member relative to the shaped body. The cooling member includes a distal end closest to the flowing molten glass and a proximal end furthest from the flowing molten glass (relative to the distal end). Preferably, the distance between the distal end of the long cooling member and the molded body can be changed, for example, by dropping the cooling member back from the molten glass or inserting the cooling member in the vicinity of the molten glass. The distance between the distal end and the shaped body (and flowing molten glass) may be achieved by pivoting the cooling member about the vertical axis described above. The cooling member may be a tube having a hollow interior or a solid rod. However, the solid rod can provide better thermal conductivity without introducing the risk of air leakage between the environment outside the seal and the inside of the seal through the hollow interior. As used herein, a rod means an elongated body and is therefore not limited to only rods that were loaded. In addition, the elongated body may have different shapes, and the shape of the rod may vary along the length of the body. In some examples, the distal end of the long body (cooling member) may have an I shape different from the long body area next to the distal end. For example, the width of the distal end is greater than the width of the proximal end of the cooling member. The distal end can be rounded (bulbous), but has a uniform cylindrical shape as it moves down the longitudinal direction of the long body, away from the rounded distal end. In another way, the shape of the distal end is different from the shape of the cooling member adjacent the distal end.

The apparatus further comprises a plurality of thickness control units and a plurality of long cooling members arranged horizontally adjacent to the longitudinal direction of the shaped body, whereby the array has a substantially uniform height relative to the shaped body root. . In another embodiment, the distance between the distal end of the plurality of cooling members and the molded body may not be uniform. This is because the individual thermal control unit can be generated with a vertical height change, or because the distal end of each cooling member is changed by rotating the cooling members about an axis of rotation, for example a horizontal axis of rotation, which is not vertical. Preferably, the distal end of the cooling tube is positioned such that the viscosity of the molten glass proximate to the distal end is in the range of 35,000 poises to 1,000,000 poises.

In some embodiments, the apparatus further comprises a temperature regulator disposed around the cooling member, configured to change the temperature of the cooling member to change the temperature difference between the distal end of the cooling member and the continuous ribbon of flowing glass. do. For example, the temperature regulator may be an electronic heating coil or cooling coil that delivers a flow of cooling water. The temperature regulator is used to change the temperature of the cooling member to change the temperature difference between the cooling member (and especially the distal end of the cooling member) and the flowing molten glass near the distal end of the cooling member.

According to yet another embodiment, a method of controlling the thickness of a continuous ribbon of molten glass in a molten underdrawing process is disclosed, wherein the method comprises flowing molten glass over a converging forming surface of a shaped body, wherein The forming surface includes a molten glass flow step that meets at the root to form a glass ribbon, and using a long cooling member located proximate to the flowing molten glass, varying the viscosity of the local area of the flowing molten glass, The viscosity of the localized region of the flowing molten glass is changed without causing a cooling gas to flow from the long cooling member toward the flowing molten glass. The long cooling member includes a proximal end and a distal end, wherein the distal end is located closer to the flowing molten glass than the proximal end, and the shape of the distal end is different from the shape of the long cooling member adjacent to the distal end. The method may also include a plurality of long cooling members, wherein the distance between the distal end of the plurality of long cooling members and the flowing molten glass is not uniform. This is because, for example, the individual cooling members may be rotated or pivoted about an axis of rotation, for example a vertical axis. In some embodiments, the distance between the long cooling member (its distal end) and the flowing molten glass is changed, for example by placing or backing the long cooling member towards or away from the glass.

In certain embodiments, the angle between the vertical plane where the root is located and the longitudinal axis of the elongate cooling member is varied. That is, the cooling member can be rotated or pivoted about an axis passing through the cooling member perpendicular to the central longitudinal axis of the cooling member, which is the angle between the central longitudinal axis and the shaped body (and its flowing molten glass) near the cooling member. To change.

In certain embodiments, the central longitudinal axis of the at least one cooling member is perpendicular to the vertical plane in which the root is located. In other words, the central longitudinal axis of the cooling member is perpendicular to the root.

In certain other embodiments, the temperature of the cooling member is varied to change the amount of heat extracted from the molten glass flowing in response to the measured thickness of the glass sheet obtained from the glass ribbon. For example, the cooling or heating coil may be in contact with or located near the cooling member, which changes the temperature difference between the temperature of the cooling member, the distal end of the cooling member and the flowing molten glass near the distal end. This can be achieved in response to the thickness measurement processed downstream of the molded root. In still other embodiments, the angular position of the cooling member can be varied to change the amount of heat extracted from the molten glass flowing in response to the measured thickness of the glass sheet obtained from the glass carbon.

In yet another embodiment, the distance between the distal end of the cooling member to the flowing molten glass is varied to change the amount of heat extracted from the flowing molten glass in response to the measured thickness of the glass sheet obtained from the glass ribbon.

By changing the angular position, the temperature of the cooling member or the win-win distance from the flowing molten glass can be treated separately or in various combinations with one another as necessary.

Additional features and advantages of the invention will be set forth in the following detailed description, and as disclosed herein, this description may be readily apparent in part to a person of ordinary skill in the art, or one of ordinary skill in the art It will be appreciated by practicing the examples. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. As should be appreciated, the various means of the invention disclosed herein and in the figures may be used in any and all combinations.

1 is a cross-sectional view of a representative fusion downdraw apparatus that produces sheet glass showing the location of cooling members that control the local thickness of a glass ribbon flowing from a forming body.
FIG. 2 is a side view of the device of FIG. 1 showing the location of a plurality of thickness control units comprising elongate cooling members in an array in a horizontal direction over at least a portion of the length, and thus the molded body length. FIG.
FIG. 3 is a side view of the apparatus of FIG. 1, showing the location of a plurality of thickness control units comprising elongate cooling members in at least a portion of the length of the device, and thus in a horizontal array across the molding length. The vertical height of each thickness control unit is not uniform.
FIG. 4 is a cross-sectional view of a portion of the cooling member used in the apparatus of FIG. 1, showing the position of the cooling member in a fixture that facilitates at least side-to-side yaw motion with respect to the long cooling member. FIG. Illustrated.
FIG. 5 is a view of the front of the fixing device for manipulating the elongate cooling member, wherein the brackets for mounting the fixing device on the device of FIG.
6 is a perspective view of a pivot member-a pivot member connected to an elongate cooling member to form a cooling member unit according to an embodiment of the present invention.
7 and 8 each show the pivot member-cooling member unit of FIG. 6 showing the position of the key on the keyway connecting the pivot member to the platform when looking straight at the end of the elongate cooling member, and the key of the platform. Partial cross-sectional view of the platform showing the location of the keys on the way.
9 is a perspective view of the pivot member-cooling member unit of FIG. 6 showing horizontal yawing of the elongate cooling member through rotation of the pivot member about a vertical axis.
10 is a perspective view of the pivot member-cooling member unit of FIG. 6 showing the vertical pitch of the elongate cooling member through the rotation of the pivot member about the horizontal axis.
11 is a perspective view of a cylinder pivot member-cooling member unit.
12 is a cross-sectional view of a portion of the fastener of FIG. 5 showing complementary mating surfaces of the socket members.
FIG. 13 shows an exemplary pivot member-cooling member unit according to an embodiment of the present invention having a distal end, such as an arcuate seat for an elongate cooling member.
FIG. 14 is a top view of the plurality of cooling members shown in the array, showing that the distance between the distal end of each cooling member and the flowing molten glass is not uniform across the array.
FIG. 15 is a top view of the plurality of cooling members shown in the array, illustrating that the angular orientation of each cooling member is not uniform across the array.

For illustrative purposes, and in the following detailed description without limitation, exemplary embodiments that disclose particular details are set forth in order to provide a thorough understanding of various principles of the invention. However, as will be apparent to one of ordinary skill in the art, the invention having the benefit of this disclosure may be practiced in other embodiments that depart from the specific details disclosed herein. In addition, descriptions of known devices, methods, and materials will be omitted to avoid ambiguity in the description of the various principles of the invention. Finally, wherever applicable, like reference numerals refer to like elements.

1 shows an apparatus 10 for drawing a glass ribbon according to a representative melt underdraw process. Apparatus 10 includes a shaped body 12, which includes an upper channel or trough 14 disposed within the shaped body. The shaped body 12 includes converging forming surfaces 16a and 16b that collect at the lower edge or drawing line 18, from which molten glass is drawn from the shaped body rotor. . Lower edge 18 may also be referred to as root 18. The molten glass 20 is supplied to the trough 14 and, when overflowed in the trough, the molten glass flows on the upper edge of the trough and converges forming surfaces 16a and 16b as two separate molten glass flows. Flows down). This separate stream of glass greening joins or joins again at the molded root, leading continuously from the root towards the bottom 21, as a single ribbon 22 of glass. Thus, the process is sometimes referred to as the melting process or the melt bottom drawing process. This portion of the molten glass in contact with the forming surface of the shaped body 12 is located within the ribbon drawn from the root 18 and the outer surface of the ribbon is left uncontaminated. The glass ribbon 22 is changed from a viscous liquid of the molded body 12 to a viscoelastic material and finally to an elastic material. When the ribbon is brought to an elastic state, the ribbon is separated, for example by scoring and snapping, to form individual glass sheets or panes 23.

In order to control the thermal environment surrounding the molten glass, the shaped body 12 is placed in a refractory enclosure or a muffle 24, the muffle being structural support members disposed around the refractory material of the muffle. Has 26. The muffle doors 28 are located below the muffle 24 along opposite sides of the glass ribbon 22 and may be moved inward or outward along the support rails 30. In order to prevent air leakage or drafts, the space between the muffle 24 and the muffle doors 28 may be filled with a suitable refractory insulating material 32, for example mineral wool fibers. Outer shield members 34 are attached to the muffle 24, and extend between the muffles 24, top down the muffle doors 28 in a skirt form, typically made of metal, For example, it is formed from metal, such as stainless steel. The shield members 34 serve to further eliminate the possibility of draft air exchange between the atmosphere in the muffle and the atmosphere outside the muffle. However, because each muffle door is configured to move inward or outward relative to the glass ribbon, the outer shield members 34 cannot be permanently attached to the muffle doors 28. In some embodiments, the shielding members 34 may be an integral part of the muffle 24, for example an extension of the support members 26.

The plurality of thickness control units 38 are located along the sides of the shaped body 12 near the root 18. For example, the thickness control units 38 can be connected to the outer shield members 34. Each thickness control unit 38 preferably comprises an elongate cooling member 40 spaced apart from adjacent elongate cooling members of adjacent thickness control units in a substantially horizontal plane 41 (see FIG. 2). However, the elongate cooling units need not all be located within the same horizontal plane. For example, in some embodiments, the elongate cooling members can be staggered in the vertical direction if desired (FIG. 3). Preferably, each cooling member is positioned adjacent to an area of the glass ribbon that falls within a viscosity range of about 35,000 poises to 1,000,000 poises, but in a vertical direction. Each thickness control unit may further comprise a fixture 42 (FIG. 4) that encloses a portion of each cooling member, and if necessary, connects the cooling member to the outer shield member. The bracket 44 of the fixing device 42 can be used to connect each thickness control unit to the outer shield member 34, and the long cooling members are spaced apart relationship on the outer shield member 34. Keep it at Each elongate cooling member 40 ends in a state very close to the molded body 12, and particularly in a state very close to the root 18. For example, each elongate cooling tube may be within about 6 cm to about 13 cm of the molded body.

Each elongate cooling member 40 is formed of a material that is capable of withstanding deformation at high temperatures in the volume 36, for example even at temperatures above 1250 ° C. In a simple form, the cooling member may be an elongated body extending very close to the shaped body, in particular an elongated body very close to the shaped body root, preferably up to a distance of less than about 10 cm from the surface of the molten glass. have. The cooling member can be a solid rod or hollow, for example a hollow tube. In some embodiments, the cooling member may be glass or quartz, ceramic or glass-ceramic. In another embodiment, the cooling member may be a metal, for example a metal rod. The solid cooling member has the advantage of not allowing heated air in the confines of the muffle to escape through the cooling member, thereby reducing the effect of the cooling member on the overall thermal environment within the muffle, but in the baffles in the hollow tube. Hollow tubes comprising baffles or barriers can likewise achieve this. The solid cooling member may also have a larger thermal mass than the hollow tube and is more effective at extracting thermal energy from flowing molten glass. Metallic cooling members generally have greater conduction properties (conducting greater thermal energy from molten glass) than ceramic or glass cooling tubes, but their rapid heat extraction may, in some instances, be higher than necessary. And by producing viscous changes. In addition, the high temperatures that some glass undergoes, as described above in close proximity to the molten glass, may render the metal coolable members unfeasible.

The elongate cooling members 40 are typically circular in cross section perpendicular to the longitudinal axis of the cooling member (see eg FIG. 7), but may further comprise other geometric shapes as well. For example, the cooling members can have an elliptical cross section, a square cross section, a triangular cross section and the like. The cooling members may be substantially flat to generally form rigid strips having a predetermined and defined horizontal width. The thickness of each strip can vary depending on the length of the strip. The appropriate vertical thickness of each strip can be readily determined to help prevent bending or other deformation.

Each cooling member can function as an adjustable heat sink, which heat sink affects the temperature of the small, localized glass of the molten glass flowing when it is very close to the flow of molten glass descending from the molded body. And therefore, the viscosity of the molten glass, and ultimately the local thickness of the molten glass. By local thickness is meant the thickness of the molten glass flowing along the horizontal strip of glass to less than about 2 cm. As deemed particularly important, the cooling member according to the embodiments disclosed herein can achieve thickness control without the use of a flowing gas from the cooling member, which is the same as used in the prior art methods, but only cooling in the glass flow. It can be used by adjusting the positioning of the members in close proximity. As such, the cooling member can act through the thermal conductivity of the cooling member. This is usually the result of radiant heat loss from the flowing glass to the cooling member.

Referring to FIG. 7, each cooling member 40 may be connected to a pivot member 46, each pivot member including a passage 48 through which the cooling member extends. The cooling member may be strongly bonded in the pivot member passage 46 with high temperature cement or the like, or the cooling member may be accommodated by another method, for example, molten glass flows down the molded body. The cooling member may be accommodated by compression fitting or clamping to allow movement inward or outward. For example, in certain embodiments, the cooling member 40 may be located proximate to the surface of the flowing glass closest to the cooling member, or the cooling member may be placed back away from the surface of the flowing molten glass. Can be. The proximity of the distal end of the cooling member to the surface of the flowing glass material can affect the amount of thermal energy removed from the molten glass by the cooling member. The cooling member may be oriented such that the longitudinal axis of the cooling member is perpendicular to the vertical plane 47 passing through the root of the molded body or that the longitudinal axis of the cooling member may be angled with respect to the vertical plane 47. . In the case where the cooling member 40 is a flattened strip, the longitudinal axis of the strip extends longitudinally through the strip, an axis equidistant from the side edges of the strip, and the top and bottom surfaces of the strip. It will be interpreted as an axis equidistant from the liver (assuming that the properties of the stream are uniform, ie thickness and width are uniform).

According to one embodiment, as best shown in FIGS. 5 and 6, each pivot member 46 may be substantially spherical in shape, for example a metallic sphere defining the passageway 48 described above. metallic sphere). Substantially a sphere means at least a portion of the outer surface in contact with mating surfaces of the socket members that are the major part of the outer surface of the pivot member or are more fully described herein below. Means. As tolerated, other parts of the pivot member that are not in contact with the complementary joint surfaces of the socket parts are not spherical or complementary, as these other surface parts do not prevent the pivot member from moving along the desired rotation. Unless it does.

Pivot member 46 may be connected to platform 50, which includes an accurate rotation stage 51 that enables accurate movement of the pivot member about the axis of rotation 52 of the platform. Pivot member 46 may be keyed to prevent relative rotational movement between platform and pivot member about vertical axis 52. As a result, the key 54 is positioned between the pivot member 46 and the platform 50 via respective corresponding slots or keyways 56 and 58 in each of the platform and pivot member. 7 and 8 showing the key removed for clarity. The key 54 can be securely fitted within the platform keyway or pivot member keyway (or both). Alternatively, the key 54 may be securely fitted to either the platform keyway or the pivot member keyway, or may only be slidably fitted within the other. For example, the key 54 may be securely fitted in the spherical pivot member keyway 58 and may be slidably fitted in the corresponding and complementary keyway 58 on the platform 50. , The spherical pivot member can rotate not only about the vertical rotation axis 52 but also about the horizontal rotation axis 53, which gives the pivot member and the cooling member two degrees of rotational freedom. Makes it possible. 9 and 10 illustrate the movement around these two degrees of freedom, ie the horizontal swing or yaw of FIG. 9 and the vertical swing or pitch of FIG. 10. do. However, since the space between the muffle door and the muffle is generally very narrow, the rotation of the pivot member about a horizontal axis of rotation that is pitch is generally limited by the contact between the elements of the muffle and / or muffle doors and the cooling member. As should be readily apparent, as further described below, by removing the key and relying on the clamping force, the pivot member 46 can be moved along the changing direction and is not limited to simple pitch and yawing.

The unitary pivot member 46 and cooling member 40 in a single unit, not permanently connected to the platform 50, can easily facilitate replacement of the pivot member and cooling member combination. For example, a particular cooling member can be facilitated by simply removing a broken pivot member-cooling member engagement to simply insert a new pivot member-cooling member unit. If a key-keyway connection between the platform and the new pivot member-cooling member is used, the new pivot member and cooling member can be placed in exactly the same angular direction as the original pivot member. Thereby, the pivot member-cooling member unit can be removed without disturbing the position of the platform 50 and the key 54, and the new pivot member-cooling member unit is the same at the angled angle position in the horizontal direction as the broken unit. Can be installed.

If only rotation about the vertical axis of rotation is required (yaw), the pivot member 46 can be cylindrical, and the central longitudinal axis of the cylindrical pivot member coincides with the rotation platform axis 52 (FIG. 11). In such a case, the mating surfaces of the socket members described in more detail below should be cylindrical to be complementary to the cylindrical pivot member.

The elongate cooling member 40 extends through the pivot member 46 via the passage 48 so that the first portion 60 of the cooling member 40 is directed from the pivot member toward the flowing molten glass. Extend, and the second portion 62 of the cooling member extends from the pivot member 46 away from the glass ribbon. The cooling member 40 includes two ends: a proximal end 64 disposed furthest from the flow of molten glass and a distal end 66 closest to the flow of molten glass. The proximal end 64 may be heated or cooled with a suitable temperature regulator 67, if desired, thereby adjusting the thickness control provided by the particular cooling member by varying the temperature of the cooling member, It may also change the temperature difference of the molten glass flowing close to the distal end. For example, the proximal end of the cooling member 40 may be selectively connected with a heating or cooling coil (FIG. 1), which coil is circulated through the cooling coil and through flowing cooling water or current that transfers heat from the cooling member. The cooling member is cooled or heated. For example, the coolant may be circulated through the cooling coils. The coolant may later flow through the heat exchanger to remove heat from the coolant. By increasing the temperature difference between the cooling member and the flowing glass and / or shaped body, the cooling effect of the cooling water can be increased.

In contrast, the cooling member can be heated by an electrical winding or coil, thereby degrading the cooling member's ability to absorb heat from the flowing glass and shaped body. By narrowing the temperature difference between the cooling member and the flowing glass and / or molded body, the cooling effect of the cooling member can be reduced.

The heating and cooling of the individual cooling members by means of a temperature regulator, for example the heating and cooling coils described above, can be included in the feedback loop, whereby the local thickness of the glass ribbon is made downstream of the cooling member, for example ribbon Near the bottom of, or in a glass sheet separated from the ribbon, the thickness data obtained is used to adjust one or more cooling elements. Glass thickness can be determined using, for example, laser triangulation methods. Suitable measurement equipment for making thickness measurements includes LMI Technologies' GTS2 thickness and side measurement sensors. For example, if the thickness of the localized region of the glass ribbon is less than the target thickness, the effectiveness of the cooling member may move the cooling member close to the glass and increase the coolant flow in the cooling coil thermodynamically connected to the cooling member, or It can be improved by reducing the temperature. If desired, the feedback loop is in communication with the thickness measuring detector via control line 73 and further with one or more actuators (not shown) connected via the control line 75 to the cooling member of each thermal control unit. It can be automated by including the controller 71 in communication (see FIG. 3). As should be noted, other temperature regulators may be used to change the temperature of cooling elements such as electronic strip heaters, thermoelectric cooling elements, and the like, and the cooling coil of FIG. 3 is not shown for purposes of limitation.

Fixing device 42 further includes a front or first socket member 74 and a back or second socket member 76, best shown in FIG. 12, with no pivot member 46 for clarity. Has been shown. The first socket member 74 includes an inner surface 78, at least a portion of which is complementary to a portion of the pivot member. The opening 80 extends through the thickness of the first socket member, so that when the pivot member 46 contacts the complementary portion of the socket inner surface 78, the cooling member 40 opens in the opening 8. Extends through). The opening 80 may be sized to allow movement of the pivot member and cooling member without disturbing the intended range of movement. That is, the opening 80 may be sized such that the pivot member rotates at least about the axis 52 such that the cooling member 40 swings or yaws in the opening. Preferably, the cooling member 40 can swing freely through an angle of at least about 40 degrees. Similarly, the second socket member 76 includes an inner surface 82 (at least a portion of the inner surface 82 is complementary to the pivot member 46), and a second opening 84, wherein The cooling member 40 extends through the second opening, so that the second portion of the cooling member 40 can swing, as the pivot member 46 rotates.

The back socket member 76 is connected to the front socket member 74, so that the pivot member 46 disposed between the front socket member and the back socket member remains stationary. For example, the front and back socket members may be connected to each other, but may be connected via bolts, screws, clips or other suitable attachment manner, such that the pivot member 46 may be secured between the socket members. For example, socket members 74 and 76 are shown connected with the bolt in FIG. 11. The pivot member 46 may first be placed so as to be within a predetermined proximal position of the molten glass through which the cooling member 40 flows, and the fastening means (eg bolts) are in the desired orientation to lock the pivot member and the cooling member. Can fit tight.

The ability of the pivot member according to this embodiment to rotate about an axis 52 to "swing" the cooling member 40 through a horizontal arc is the width of the molten glass compared to the fixed cooling members. Facilitates the reduction in the number of thickness control units 38 necessary to reach. For example, the elongate cooling member 40 can be rotated via the pivot member 46 through an angle of at least about 10 degrees, 20 degrees, 30 degrees, or even 40 degrees or more. In addition, depending on the thermally conductive properties of the cooling member rather than the release of the cooling gas, the cooling members are simpler to install and maintain (e.g., there is no external tube for delivering the cooling gas, and the composite gas meter also none).

Unlike the conventional cooling method, according to the present embodiment, the cooling member 40 may be located farther than the fixed cooling member. If cooling is required in a particular area of flowing molten glass, because of the thickness effect, the cooling member located closest to the defect can swing laterally in place by rotating the platform 50, thus cooling member 40, In this way, the cooling member can be located very close to the defect area. In addition, each cooling member may be located behind (away from the flowing molten glass) or inserted (toward the flowing molten glass) so that the distance between the flowing molten glass and the distal end of the cooling member may be varied. As a result, the number of openings in the muffle inner volume is reduced. The number of openings is reduced, thereby reducing the risk of uncontrolled drafts due to leakage into (or out of) the volume 36 surrounded by the muffle 24. Each elongate cooling member, in combination with the other cooling member, does not need to rotate through pivot member 46 or move outwards or outwards towards flowing molten glass.

In some embodiments, the elongate cooling member 40 has a straight shape and has a uniform cross-sectional shape, perpendicular to the longitudinal axis of cooling. However, in other embodiments, each cooling member may include a modified distal end having a different shape than a portion of the cooling member adjacent to the distal end. The pivot member may include, for example, a crescent distal end, partly cylindrical distal end or disc distal end. 13 shows an elongate cooling member 40 having an arcuate end similar to a portion of the cylinder wall. The cooling member may comprise a more complex distal end when it is necessary to control localized areas of flowing glass, such as combined portions of different geometric shapes. This modified cooling member has a larger distal end (in a direction perpendicular to the longitudinal axis 88 of the elongate cooling member) than the proximal end of the cooling members.

As is apparent from the foregoing description, the location of the individual cooling elements can be used to effectively control the local thickness of the ribbon of glass drawn from the molten glass and ultimately even the thickness of the individual glass sheet or plate glass separated from the ribbon. Can be. According to the embodiments described herein, the individual cooling members can be rotated (can be pivoted) about one or more axes to change the angular orientation of the cooling members relative to the shaped body and the molten glass. For example, individual cooling members can be pivoted about a vertical axis, resulting in a side-to-side swing. Individual cooling members can be inserted close to the flowing molten glass, thereby reducing the distance between the distal end of the cooling member and the flowing molten glass. Alternatively, individual cooling elements can be positioned backwards, as a result of which the distance between the flowing molten glass and the distal end of the cooling element is increased. Accordingly, the angular orientation of the individual cooling members, and the distance away from the distal end of each individual cooling member and flowing molten glass, are affected regardless of the distal end distance and angular orientation of another cooling member in the array of cooling members. In this way, a cooling profile over the width of the flowing glass that is suitable for the setup to make a particular glass can be introduced. FIG. 14 shows a representative array of cooling members viewed from above, wherein individual cooling members are located at different distances from the flowing molten glass (where the downward flow of molten glass is shown by the edges on plane 100). Each cooling tube of FIG. 14 is shown as a straight rod, but according to the initial description, the size and shape of each cooling member can be changed as necessary. Similarly, FIG. 15 is a view looking back down at the array of cooling members, showing an array of cooling members having different angular orientations to create different cooling profiles over the width of the flowing molten glass. As shown in FIG. 15, the cooling member is adjusted for both the distal end of each cooling member and the distance of the molten glass flowing, and the angular position.

Representative non-limiting examples include the following:

C1. In the process of making bottom draw glass, a device for forming a continuous ribbon of molten glass:

A molded body comprising a converging forming surface that gathers into a root;

A seal disposed around the molded body; And

At least one thickness control unit connected to the seal and for varying the local temperature of the molten glass,

The thickness control unit includes an elongate cooling member extending close to the molten glass flowing on the molded body, and air does not flow from the cooling member toward the molten glass.

C2. In C1, the cooling member is rotatable about a vertical axis.

C3. In C1 or C2, the cooling member includes a distal end closest to the flowing molten glass, and the distance between the distal end of the long cooling member and the molded body can be changed.

C4. In any one of C1 to C3, the said cooling member is a solid rod.

C5. The cooling member according to any one of C1 to C4, wherein the cooling member includes a distal end closest to the flowing molten glass, and the shape of the distal end is different from that of the cooling member adjacent to the distal end.

C6. In C5, the width of the distal end is greater than the width of the proximal end of the cooling member.

C7. The glass ribbon forming apparatus according to any one of C1 to C6, further includes a plurality of long cooling members arrayed adjacent to the length of the molded body in a horizontal direction.

C8. In C7, the distance between the distal end of the plurality of cooling members and the molded body is not uniform.

C9. In any one of C1 to C8, the distal end of the cooling member is positioned so that the viscosity of the molten glass proximate to the distal end is in the range of 35,000 poises to 1,000,000 poises.

C10. The glass ribbon forming apparatus of claim 1, wherein the glass ribbon forming apparatus further includes a temperature regulator configured to change a temperature of the cooling member to change a temperature difference between the distal end of the cooling member and the continuous ribbon of flowing glass. .

C11. The glass ribbon forming apparatus according to any one of C1 to C10, wherein the glass ribbon forming apparatus further includes a plurality of cooling members, wherein a vertical height of the first cooling member of the plurality of cooling members with respect to the route is equal to the plurality of cooling with respect to the route. Different from the vertical height of the second cooling member of the members.

C12. To control the thickness of the continuous ribbon of molten glass in the melt draw process:

Allowing molten glass to flow over the convergent forming surface of the molded body, the convergent forming surface having a molten glass flow step meeting at the root to form a glass ribbon; And

Using a long cooling member positioned proximate to the flowing molten glass to change the viscosity of a localized region of the flowing molten glass,

The viscosity of the localized region of the flowing molten glass is changed without causing a cooling gas to flow from the long cooling member toward the flowing molten glass.

C13. In C12, the elongate cooling member includes a proximal end and a distal end, the distal end being located closer to the flowing molten glass than the proximal end, and the shape of the distal end is of the long cooling member adjacent to the distal end. It is different from the shape.

C14. In C12 or C13, the distance between the elongate cooling member and the flowing molten glass is changed.

C15. In any one of C12 to C14, the angle between the longitudinal axis of the elongate cooling member and the vertical plane in which the root is located is changed.

C16. A part of the longitudinal axis of at least one cooling member is perpendicular to the vertical plane in which the root is located, according to any one of C12 to C15.

C17. The method according to any one of C12 to C16, wherein the glass ribbon thickness control method changes the temperature of the cooling member to change the amount of heat extracted from the flowing molten glass in response to the measured thickness of the glass sheet obtained from the glass ribbon. It further comprises a step.

C18. The method of any one of C12 to C17, wherein the glass ribbon thickness control method changes the angular position of the cooling member to change the amount of heat extracted from the flowing molten glass in response to the measured thickness of the glass sheet obtained from the glass ribbon. It further comprises the step of.

C19. The method according to any one of C12 to C18, wherein the glass ribbon thickness control method includes a distance between the distal ends of the cooling members to change the amount of heat extracted from the flowing molten glass in response to the measured thickness of the glass sheet obtained from the glass ribbon. It further comprises the step of changing.

C20. The method of any one of C12 to C19, wherein the varying step includes a plurality of long cooling members each comprising a proximal end and a distal end, and a distance between the distal end of the plurality of long cooling members and the flowing molten glass is not uniform. .

As should be emphasized in the above-described embodiments of the present invention, particularly the "preferred" embodiments are merely illustrative and therefore merely to illustrate a clear understanding of the various principles of the present invention. Many variations and modifications may be made to the above-described embodiments of the invention without departing substantially from the various principles and techniques 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.

Claims

In the apparatus 10 for forming a continuous ribbon of molten glass 22 in the process of making downdraw glass,
A molded body 12 including converging forming surfaces 16a and 16b for gathering into the root 18;
A seal 24 disposed around the shaped body; And
At least one thickness control unit 38 connected to the seal and for varying the local temperature of the molten glass,
The thickness control unit includes an elongate cooling member (40) extending proximate to the molten glass flowing on the molded body, wherein air does not flow from the cooling member toward the molten glass.

The method according to claim 1,
And the cooling member (40) is rotatable about a vertical axis.

The method according to claim 1 or 2,
The cooling member 40 includes a distal end closest to the flowing molten glass,
Wherein the distance between the distal end (66) of the elongate cooling member and the shaped body (12) can be varied.

The method according to any one of claims 1 to 3,
The cooling member (40) is a glass ribbon forming apparatus, characterized in that the solid rod.

The method according to any one of claims 1 to 4,
The cooling member (40) includes a distal end (66) closest to the flowing molten glass, wherein the shape of the distal end is different from the shape of the cooling member adjacent the distal end.

The method according to claim 5,
And the width of the distal end (66) is greater than the width of the proximal end (64) of the cooling member (40).

The method according to any one of claims 1 to 6,
The glass ribbon forming apparatus further comprises a plurality of long cooling members (40) arranged adjacent to the length of the molded body in the horizontal direction.

The method of claim 7,
Wherein the distance between the distal end (66) of the plurality of cooling members (40) and the shaped body (12) is not uniform.

The method according to any one of claims 1 to 8,
The distal end (66) of the cooling member (40) is positioned so that the viscosity of the molten glass proximate to the distal end is in the range of 35,000 poises to 1,000,000 poises.

The method according to any one of claims 1 to 9,
The glass ribbon forming apparatus is configured to change the temperature of the cooling member 40 to change the temperature difference between the distal end 66 of the cooling member and the continuous ribbon 22 of flowing glass. Glass ribbon forming apparatus further comprises a.

The method according to any one of claims 1 to 10,
The glass ribbon forming apparatus further includes a plurality of cooling members 40,
Wherein the vertical height of the first cooling member of the plurality of cooling members relative to the root 18 is different from the vertical height of the second cooling member of the plurality of cooling members relative to the root. .

In the method of controlling the thickness of the continuous ribbon 22 of molten glass in the molten underdrawing process,
Allowing molten glass to flow over the convergent forming surfaces (16a, 16b) of the shaped body (12), wherein the convergent forming surface comprises a molten glass flow step that meets at the root (18) to form a glass ribbon; And
Changing the viscosity of a localized region of the flowed molten glass using an elongate cooling member 40 positioned proximate to the flowed molten glass,
The viscosity of the localized region of the flowing molten glass is changed without causing a cooling gas to flow from the long cooling member toward the flowing molten glass.

The method of claim 12,
The elongate cooling member 40 includes a proximal end 64 and a distal end 66,
The distal end is located closer to the flowing molten glass than the proximal end,
The shape of the distal end is different from the shape of the long cooling member adjacent to the distal end.

The method according to claim 12 or 13,
And the distance between the elongate cooling member (40) and the flowing molten glass is varied.

The method according to any one of claims 12 to 14,
Wherein the angle between the longitudinal axis of the elongate cooling member (40) and the vertical plane on which the root (18) is located is varied.

The method according to any one of claims 12 to 15,
At least part of the longitudinal axis of the at least one cooling member (40) is perpendicular to the vertical plane in which the root (18) is located.

The method according to any one of claims 12 to 16,
The method of controlling the glass ribbon thickness further includes changing the temperature of the cooling member 40 to change the amount of heat extracted from the flowing molten glass in response to the measured thickness of the glass sheet obtained from the glass ribbon. A glass ribbon thickness control method characterized by the above-mentioned.

The method according to any one of claims 12 to 17,
The method for controlling the glass ribbon thickness includes changing the angular position of the cooling member 40 to change the amount of heat extracted from the flowing molten glass in response to the measured thickness of the glass sheet obtained from the glass ribbon 22. Glass ribbon thickness control method further comprising.

The method according to any one of claims 12 to 18,
The method of controlling the glass ribbon thickness is the distance between the distal end 66 of the cooling member 40 to change the amount of heat extracted from the flowing molten glass in response to the measured thickness of the glass sheet obtained from the glass ribbon 22. Glass ribbon thickness control method characterized in that it further comprises the step of changing.

The method according to any one of claims 12 to 19,
The varying step includes a plurality of long cooling members 40 each comprising a proximal end 64 and a distal end 66, wherein the distance between the distal ends of the plurality of long cooling members and the flowing molten glass is not uniform. Glass ribbon thickness control method, characterized in that not.