WO2010014167A2

WO2010014167A2 - Devices for vertical treatment of glass

Info

Publication number: WO2010014167A2
Application number: PCT/US2009/004234
Authority: WO
Inventors: James W. Brown; Paul O. Johnson; Gautam N. Kudva; Ljerka Ukrainczyk
Original assignee: Corning Incorporated
Priority date: 2008-07-31
Filing date: 2009-07-21
Publication date: 2010-02-04
Also published as: CN102137821A; TWI395720B; WO2010014167A3; TW201022169A; CN102137821B; JP2011529439A; JP5681628B2; KR20110055560A; KR101577850B1

Abstract

An apparatus (10) for treating a substantially planar glass sheet (30) that is positioned in a substantially vertical plane. In one aspect, the glass sheet is for an LCD display. The glass treatment apparatus includes a washing section (200), a rinsing section (300), a drying section (400), and bottom rollers (510) to move the glass sheet therethrough along a conveyance path (100). The washing section includes drive rollers (530, 540) configured to support and drive the glass sheet without causing damage thereto. The rinsing section includes an arrangement of nozzles (310, 320) and liquid bearings (330, 340) for rinsing the glass sheet without causing excessive vibration. And the drying section includes an arrangement of air knives (410, 420) and fluid bearings (440, 450) for drying the glass sheet without causing excessive vibration.

Description

SP08-133

DEVICES FOR VERTICAL TREATMENT OF GLASS

RELATED APPLICATION

[0001] This application claims the benefit of priority of U.S. Provisional Application Serial No. 61/085,103, filed on July 31, 2008 entitled, "Devices for Vertical Treatment of Glass," the content of which is relied upon and incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The field of this invention relates generally to glass treatment, and more particularly to devices for the vertical washing, rinsing, and drying, of LCD glass.

BACKGROUND

[0003] Glass cutting, grinding and polishing are prime operations in display glass finishing. Glass debris in the form of particles or chips is generated during all these process steps. This debris, along with various coatings that are applied to the glass to protect the glass surfaces, must be removed to enable the subsequent steps required to manufacture a saleable liquid crystal display ("LCD"). Typically, a glass cleaner specifically designed for LCD glass, is used. The vast majority of these cleaners fall into two categories, batch or inline. [0004] Inline type cleaners can generally be put into two categories, horizontal, where the glass is placed flat onto a belt or some other type drive system, or vertical where the glass sheet is supported by one edge or by one edge and a sacrificial side as the glass sheet moves through the washer steps. The vertical type is becoming more preferred because the vertical type reduces the amount of floor space required and can also produce cleaner glass, since the vertical type allows prior and subsequent process steps the opportunity of using a vertical orientation. Further, this vertical orientation reduces the amount of debris that actually clings to the glass sheet. Generally, particulate will fall downward and by changing the orientation of the glass sheet, the effective surface area is reduced which results in less air borne debris clinging to the glass sheet.

[0005] Most conventional vertical inline cleaners are manufactured for the window industry and generally do not take into account the low lateral stiffness associated with an extremely thin glass sheet, as used in the manufacture of LCD devices. For example, brushes are typically used for agitation to remove debris from the glass sheet. However, two problems arise when transporting the glass sheet through the brush section. First, adequate driving force must be applied to the glass sheet so that the force of the brushes is overcome. Second, the glass will need to be adequately supported to avoid breakage yet so as to avoid large contact areas on the glass sheet which may cause defects for example scratches, which are unacceptable to LCD customers.

[0006] Also, in the rinsing and drying sections, the glass sheet must be adequately supported so that the glass sheet does not undergo excessive vibration which may cause the glass sheet to come into undesired contact with a portion of the rinsing or drying sections. Such undesired contact may scratch or break the glass sheet in a substantially vertical orientation.

SUMMARY

[0007] The present disclosure relates to an apparatus for treatment, including washing, rinsing, and drying, of substantially planar glass sheets in a substantially vertical orientation. [0008] In one embodiment, there is provided a washing section. In the washing section, brushes are used to agitate and remove debris from the surface of the glass sheet. Drive rollers are used in the washing section to convey the glass sheet through the brushes. The size and material of the drive rollers are specified to provide adequate force to the glass sheet to convey the glass sheet through the washing section, to provide adequate support to avoid breakage of the glass sheet, and yet minimize contact area with the glass sheet so as to avoid defects, for example scratches.

[0009] In a second embodiment, there is provided a rinsing section. In the rinsing section the position of rinsing nozzles and bearings is designed to adequately support the glass sheet without causing excessive vibration. In particular, a rinsing nozzle is positioned on one side of the glass sheet, and a bearing is disposed on an opposite side of the glass sheet, across from the rinsing nozzle.

[0010] In a third embodiment, there is provided a drying section having air knives to dry the glass sheet. Fluid bearings support the glass sheet as the glass sheet is conveyed through the drying section. A first set of bearings is provided upstream of the air knives, in the conveyance direction of the glass sheet, whereas a second set of bearings is provided downstream of the air knives. The air knives are positioned on opposite sides of the glass sheet, each supplying an air stream at a specified pressure. Further, the distance between the first bearings and the second bearings leaves an unsupported length of the glass sheet. The difference in pressure applied by the air knives, and the distance between the first and second bearings, are designed so as to avoid excessive vibration in the glass sheet. [0011] Although the three embodiments are described separately, any combination thereof may be used together. That is, the washing section, rinsing section, and drying sections may be used as separate, stand-alone, units, with various other processes and/or apparatuses in between. Alternatively, the washing, rinsing and drying sections may be used one after another as shown. Still further, any two of the sections may be used one after another, and those two sections may be separated from the third section by other processes and/or apparatuses.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] These and other features of the preferred embodiments of the invention will become more apparent in the detailed description in which reference is made to the appended drawings wherein:

[0013] FIG. 1 is a front perspective view of one embodiment for a glass treatment apparatus. [0014] FIG. 2 is a rear perspective view of the glass treatment apparatus of FIG. 1. [0015] FIG. 3 is a rear plan view of the glass treatment apparatus of FIG. 1, showing a washing section, a rinsing section, and a drying section.

[0016] FIG. 4 is a top elevational view of the glass treatment apparatus of FIG. 1. [0017] FIG. 5 is plan view of the glass treatment apparatus as seen from the left of FIG. 1. [0018] FIG. 6 is a front plan view of the glass treatment apparatus of FIG. 1. [0019] FIG. 7 is a cross-sectional view of the glass treatment apparatus as taken along line 7- 7 of FIG. 6.

[0020] FIG. 8 is a cross-sectional view of the glass treatment apparatus of FIG. 6, cut along line 8-8.

[0021] FIG. 9 is a blown-up view of two drive rollers in the washing section of the glass treatment apparatus of FIG. 1. [0022] FIG. 10 is side plan view of the drive rollers shown in FIG. 9.

DETAILED DESCRIPTION

[0023] The present invention can be understood more readily by reference to the following detailed description, examples, drawing, and claims, and their previous and following description. However, before the present devices, systems, and/or methods are disclosed and described, it is to be understood that this invention is not limited to the specific devices, systems, and/or methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

[0024] The following description is provided as an enabling teaching of the invention in its best, currently known embodiments. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the invention described herein, while still obtaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be obtained by selecting some of the features disclosed herein without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances and are a part of the present invention. Thus, the following description is provided as illustrative of the principles of the present invention and not in limitation thereof. [0025] As used throughout, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a glass sheet" can include two or more such glass sheets unless the context indicates otherwise. [0026] 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 aspect 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 aspect. 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.

[0027] As used herein, the terms "optional" or "optionally" mean that the subsequently described event or circumstance can or can not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. [0028] There is described a glass treatment apparatus 10 for treating a substantially planar glass sheet 30. The glass treatment apparatus 10 may include a washing section 200, a rinsing section 300, and a drying section 400. The glass sheet 30 generally has a first face 32 and an opposed second face 34, as seen in FIG. 4. The glass sheet 30 may be used, for example, for an LCD display.

[0029] In one exemplary aspect, the glass sheet 30 is conveyed along a conveyance path 100, in a conveyance direction 102 through the washing section 200, the rinsing section 300, and the drying section 400. See FIG. 4. The glass sheet 30 is conveyed in a substantially vertical manner along the conveyance path 100. The glass sheet is conveyed using a plurality of bottom rollers 510 positioned at a bottom portion of the conveyance path 100. The bottom rollers 510 can be in communication with a bottom roller drive 520 for imparting a rotational force on one or more of the bottom rollers 510 to convey the glass sheet 30 along the conveyance path 100 and through the washing section 200, rinsing section 300, and drying section 400. Each section, i.e., washing 200, rinsing 300, and drying 400, may have its own roller drive 520 for the bottom rollers 510 in that section. Such an arrangement is beneficial when the sections are used separately as stand-alone units. Alternatively, one roller drive 520 can be used for more than one section. As shown, one roller drive 520 is used for both the washing 200 and rinsing 300 sections, whereas a separate roller drive 520 is used for the drying section 400. The roller drive 520 may be connected to the bottom rollers 510 by any known type of drive train, as would be understood by one of ordinary skill in the art. [0030] Washing Section

[0031] In one aspect, the glass treatment apparatus 10 comprises a washing section 200 that includes a wash housing 20 and the conveyance path 100 therethrough. The glass sheet 30 is oriented in a substantially vertical orientation as the glass sheet 30 travels along the conveyance path 100 in the conveyance direction 102.

[0032] The washing section 200 includes at least one first brush 210 positioned adjacent the conveyance path 100 and configured to contact at least a portion of the first face 32 of the glass sheet 30 for the purposes of washing debris off of the first face 32. Additionally, the washing section 200 also includes at least one second brush 220 positioned adjacent the conveyance path 100 and configured to contact at least a portion of the second face 34 of the glass sheet 30. The washing section 200 is configured such that the at least one first brush 210 is positioned opposite the at least one second brush 220. To be clear, the axes 212, 222 of the first 210 and second 220 brushes are positioned on opposite sides of the conveyance path 100. However, the diameter of the brushes is such that each brush, when extended with no glass sheet between the brushes 210, 220, extends across the conveyance path 100 so that when the glass sheet is present, the brush makes a sufficient contact area on the glass sheet 30 so as to agitate unwanted particles from the glass sheet 30. The washing section 200 can comprise a plurality of pairs of brushes 210, 220, which are disposed along the conveyance path wherein the axes 212, 222 of the brushes 210, 220 of each pair are on opposite sides of the conveyance path 100. In this manner, any normal forces put on the first face 32 of the glass sheet 30 by one of the first brushes 210 can be substantially equal to and opposite of any normal forces put on second face 34 of the glass sheet 30 by one of the second brushes 220.

[0033] To assist in washing, the brushes 210, 220 can rotate. For example, and not meant to be limiting, the first brush axis 212 is substantially parallel to the glass sheet 30. Similarly, the second brush axis 222 is substantially parallel to the glass sheet 30. A motor 250 is connected via a suitable drive train (not shown for the sake of simplicity, but as would be readily understood by one of skill in the art) to the first brush axes 212 and the second brush axes 222 so as to rotate them together. The brushes 210, 220 are rotated in a direction that would tend to oppose travel of the glass sheet 30 along the conveyance path 100 in the conveyance direction 102. As shown in FIG. 4, for example, the first brushes 210 would spin clockwise, whereas the second brushes 220 would spin counter-clockwise, hi order to provide suitable agitation for removing debris, as well as to allow the drive rollers 530, 540 (as described below) to control the speed of conveyance of the glass sheet 30 along the conveyance path 100, the brushes may be rotated at a speed of about 200 surface feet per minute (sfpm) to about 1000 sfpm (60 to 305 surface meters per minute), for example, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, or 950 sfpm (75, 90, 105, 120, 135, 150, 165, 180, 195, 210, 225, 240, 260, 275, 290 surface meters per minute). Although two pairs of first 210 and second 220 brushes are shown, any suitable numbers of pairs of brushes may be used.

[0034] In addition to the bottom conveying rollers 510, to assist in facilitating conveying the glass sheet 30, the glass treatment apparatus 10 also includes a plurality of first drive rollers 530 positioned adjacent to and on one side of the conveyance path 100, and a plurality of second drive rollers 540 positioned adjacent to and on a second side of the conveyance path 100. In one aspect, each of the plurality of first drive rollers 530 is substantially opposite a corresponding second drive roller 540 and each of the plurality of second drive rollers 540 is substantially opposite a corresponding first drive roller 530. In order to convey the glass sheet, each of the plurality of first drive rollers 530 is configured to contact a portion of the first face 32 of the glass sheet 30 and each of the plurality of second drive rollers 540 is configured to contact a portion of the second face 34 of the glass sheet 30. [0035] A plurality of first drive rollers 530 is disposed on a shaft 534 to support the glass sheet 30 in the vertical direction. The number of first drive rollers 530 on each shaft 534 depends upon the size of the glass sheet, and can vary accordingly. Similarly, a plurality of second drive rollers 540 is disposed on each shaft 544. A plurality of first shafts 534 and a plurality of second shafts 544 are disposed in pairs along the conveyance path, wherein the first shafts 534 are disposed on one side of the conveyance path 100, and the second shafts 544 are disposed on an opposite side of the conveyance path 100. A motor 550 is connected to the first 534 and second 544 shafts by a suitable drive train (not shown for sake of simplicity, but as would be readily understood by one of skill in the art). As shown in FIG. 4, the motor 550 and drive train would cause the first drive rollers 530 to rotate in a counterclockwise direction, whereas they would cause the second drive rollers 540 to rotate in a clockwise direction to cause the glass sheet 30 to move along the conveyance path 100 in the conveyance direction 102. Although three pairs of first 534 and second 544 shafts are shown, any suitable number of pairs may be used.

[0036] Further, size and material of the drive rollers are designed so as to provide an adequate driving force to convey the glass sheet 30 through the washing section 200 against the force applied by the brushes 210, 200, to provide adequate support to avoid breakage of the glass sheet 30, and yet minimize contact area with the glass sheet 30 so as to avoid defects, for example, scratches.

[0037] A drive roller 530 includes a thickness 536 over the portion of the drive roller 530 that contacts the glass sheet, and a diameter 538. See FIG. 10 showing the diameter and thickness for one drive roller 530. Each of the other drive rollers 530 and 540 has a similar thickness and diameter. The thickness 536 may be in the range of about 0.5 inches to about 2 inches (1.27 cm to about 5.08 cm). As thickness 536 increases, there is produced a greater contact area with the glass sheet 30 which increases the risk of damage to the glass sheet. Also, as thickness 536 increases, it is harder to balance the eccentricity produced in the shafts 534, 544 as a result of the reaction force from a drive roller 530, 540 pushing on the glass sheet 30 to make the glass sheet 30 move in the conveyance direction 102 along the conveyance path 100. As the shaft eccentricity increases, it is more difficult to maintain an acceptable space between the drive rollers 530, 540 for the glass sheet 30 to travel. On the other hand, if the thickness 536 is too small, then there will not be a sufficient amount of drive force to move the glass sheet 30 through the washing section 200. The diameter 538 of a drive roller 530 may be up to about 4 inches. The diameters of the first 530 and second 540 drive rollers, as well as the placement of the shafts 534, 544, are chosen so that the rollers 530, 540 are spaced from one another by a gap 560 that is less than the thickness 36 of the glass sheet 30 to be conveyed. See FIGS. 9 and 10. Stated another way, the shafts 534, 544 in each pair of shafts are spaced from one another by a distance less than the sum of half of the diameter of a first drive roller 530 plus half of the diameter of a second drive roller 540, plus the thickness 36 of the glass sheet 30 to be conveyed. The material of the first and second drive rollers 530, 540 is chosen so that the drive rollers 530, 540 are compliant. Generally, a few tenths of a millimeter compliance is acceptable. Thus, when the glass sheet 30 is conveyed through the gap 560 between the drive rollers 530, 540, the drive rollers 530, 540 are compressed (due to their compliance) to accommodate the thickness 36 of the glass sheet 30. For example, the thickness 36 of the glass sheet 30 may be about 1 mm or less, for example, about 0.8 mm about 0.7 mm, about 0.6 mm, about 0.5 mm, or about 0.4 mm. [0038] The material of the drive rollers also affects conveyance of the glass sheet. The material is one that does not stain or scratch the glass sheet, and one that has an acceptable coefficient of friction with the glass sheet 30 so as to avoid slippage between the drive rollers 530, 540 and the glass sheet 30 during conveyance of the glass sheet 30. In light of the foregoing, at least an external portion 532, 542 of the drive rollers 530, 540 comprises a polymerized rubber, for example ethylene propylene diene monomer (EPDM), or Santoprene rubber for example. See FIG. 9. The polymerized rubber may have a hardness between about 30 Shore A to about 60 Shore A, for example 35, 40, 45, 50, or 55 Shore A. [0039] As mentioned above, the first 530 and second 540 drive rollers are positioned substantially opposite each other. One reason for this configuration is to balance normal forces. Ln one aspect, each of the plurality of first rollers 530 imparts a first normal force on the first face 32 of the glass sheet 30 and each of the corresponding second rollers 540 imparts a second normal force on the second face 34 of the glass sheet 30. In another aspect, the first normal force is substantially equal to the second normal force. Keeping the opposing normal forces substantially equal drastically reduces any vibration imparted to the glass sheet 30.

[0040] The washing section 200 also includes a plurality of nozzles 230, such that nozzles 230 are disposed on both sides of the conveyance path 100. The nozzles 230 are disposed between each successive pair of drive rollers 530,540 and pair of brushes 210,220 along the conveyance direction 102. The nozzles 230 may spray any type of fluid toward the drive rollers 530,540, brushes 210,220, and glass sheet 30 to assist in the washing process. The fluid may be any type of cleaning fluid, for example, and will typically be a liquid. [0041] Rinsing Section

[0042] The rinsing section 300 includes first rinse nozzles 310 and second rinse nozzles 320 disposed on opposite sides of the conveyance path 100 from one another, and also includes first 340 and second 330 liquid bearings disposed on opposite sides of the conveyance path 100 from one another. See FIG. 4. The first 310 and second 320 rinse nozzles are positioned relative to each other and to the first 340 and second 330 liquid bearings so as to support the glass sheet 30 without causing excessive vibration that may result in damage to the glass sheet 30.

[0043] First rinse nozzles 310 are disposed on pipes 312 and are positioned substantially adjacent the glass conveyance path 100. The first rinse nozzles 310 are in communication with a liquid source, through pipes 312. Any suitable number of rinse nozzles 310 may be disposed on a pipe 312, depending upon the size of the glass sheet 30 being conveyed. Additionally, although two pipes 312 having first rinse nozzles 310 thereon are shown in the rinsing section 300, any suitable number of pipes 312 may be used for the first rinse nozzles 310. In one aspect, the liquid comprises water, but other liquids suitable for rinsing are contemplated, as well as detergents. The first rinse nozzles 310 are configured to direct liquid toward the first face 32 of the glass sheet 30.

[0044] The second rinse nozzles 320 are positioned adjacent the conveyance path 100, on the opposite side of the conveyance path 100 from the first rinse nozzles 310. Additionally, as shown in FIG. 4, the first 310 and second 320 rinse nozzles are staggered in their horizontal position along the conveyance path 100. This arrangement assists in reducing vibration in the glass sheet 30. The second rinse nozzles 320 also are in communication with a liquid source via pipes 312, and are configured to direct liquid toward the second face 34 of the glass sheet. Similarly to the first rinse nozzles 310, any number of second rinse nozzles 320 may be used on each pipe 312, and any suitable number of pipes 312 having second rinse nozzles 320 may be used in the rinsing section.

[0045] The first liquid bearings 340 each have a top 342 and a bottom 344, and is disposed so as to face the second face 34 of the glass sheet 30. See FIGS. 4 and 6. The first liquid bearings (and second liquid bearings 330) maintain a thin film of water on their surface and prevent glass contact with the liquid bearings. Such liquid bearings provide extremely high stiffness when the glass sheet is thin and ensure the absence of contact with the glass sheet 30. The first liquid bearings 340 are positioned on the opposite side of the conveyance path 100 from, and substantially opposite to, the first rinse nozzles 310 in both a horizontal and vertical manner. In the horizontal direction, both the first rinse nozzles 310 and the first liquid bearings 340 are positioned at like locations along, but on opposite sides of, the conveyance path 100. See FIG. 4. Additionally, in the vertical direction, at least some of the nozzles 310 are disposed between the top 342 and bottom 344 of the first liquid bearings 340. See FIG. 6. Preferably, most of the rinse nozzles 310 are so disposed. In this fashion, the first liquid bearings 340 face the second face 34 of the glass sheet 30, and provide a non- contact support for the glass sheet 30 directly opposite the normal forces applied by the liquid from the first rinse nozzles 310. The first liquid bearings 340 are disposed in horizontal rows, wherein four rows are shown. See FIG. 6. Any suitable number of rows may be used, depending upon the size of the glass sheet 30 to be conveyed. The rows of first liquid bearings 340 extend along a direction parallel to the conveyance direction 102 through the extent of the rinsing section 300. However, within each row of first liquid bearings 340, there are gaps 348 to accommodate the spray of second nozzles 320 toward the second face 34 of glass sheet 30. These gaps 348 allow a portion of the second face 34 to be disposed so as to directly receive fluid from the second rinse nozzles 320 at a point where the first face 32 of the glass sheet 30 is still supported by the second liquid bearings 330. [0046] The second liquid bearings 330 are positioned adjacent the conveyance path 100 on the opposite side of the conveyance path 100, and substantially opposite to, the second rinse nozzles 320. The number and arrangement of the second liquid bearings 330 can be similar to that described above with respect to the first liquid bearings 340. Additionally, the relationship of the second liquid bearings 330 with respect to the first 310 and second 320 rinse nozzles and first liquid bearings 340 can be similar to that of the first liquid bearings 340 with respect to the second 320 and first 310 rinse nozzles and the second liquid bearings 330, as described above.

[0047] The first 310 and second 320 rinse nozzles may direct liquid at the first 32 and second 34 faces of the glass sheet 30 in a wide range of acceptable volumetric rates and pressures. Accordingly, in one aspect, the liquid is directed at the first 32 and second 34 faces of the glass sheet 30 at a rate of from about 0.2 to about 2 GPM. In another aspect, the liquid is directed at the first 32 and second 34 faces of the glass sheet 30 with a pressure from about 10 to about 50 psi (about 68950 N/m² to about 344738 Wm²). When the volumetric flow rate and the pressure fall within these ranges, with the positional relationships as described above, the liquid causes the glass sheet 30 to vibrate about 50 microns or less, which is not excessive for glass sheets 30 employed in typical LCD devices. [0048] Drying Section

[0049] The drying section 400 is designed to remove liquid from the faces 32,34 of the glass sheet 30. In one aspect, the drying section 400 includes at least one first air knife 410, a second air knife 420, nozzles on pipes 430, fluid bearings 440, 450, and guide rollers 470. The pressure of air applied by the air knives 410, 420, and the distance between the fluid bearings 440, 450, are designed to so as to avoid undesirable vibration in the glass sheet. [0050] The first air knife 410 is positioned adjacent the conveyance path 100 and in communication with a gas source. The first air knife 410 is configured to direct gas toward the first face 32 of the glass sheet 30, as the glass sheet 30 passes along the conveyance path 100 in the conveyance direction 102, in order to form a curtain of gas that removes liquid from the first face 32 of the glass sheet 30.

[0051] Similarly, in this aspect, there is at least one second air knife 420 positioned adjacent the conveyance path 100 in communication with a gas source and configured to direct gas toward the second face 34 of the glass sheet 30, as the glass sheet 30 moves along the conveyance path 100 in the conveyance direction 102. The second air knife 420 is positioned substantially opposite the first air knife 410. The air flow on either side of the sheet 30 is precisely controlled to reduce vibration in the glass sheet 30, from an imbalance in pressure, to an acceptable level. An imbalance in pressure occurs when an air knife on one side of the glass sheet 30 applies a pressure different from that of another air knife disposed on an opposite side of the glass sheet 30. Excessive vibration not only causes scratches, but also prevents efficient drying. A pressure imbalance of a few hundred Pascals can cause undesired vibration and affect drying. Each air knife 410, 420 directs gas at the glass sheet 30 at a rate between about 1500L/min and 2800L/min, however, other ranges are contemplated, for example 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, and 2700 L/min. The gas can be compressed air. Other gases are contemplated, as well, including but not limited to blower air and nitrogen.

[0052] The drying section 400 includes first and second fluid bearings 440, 450 to support the glass sheet 30 as the glass sheet 30 is conveyed past the air knives 410, 420. First bearings 440 are located upstream of the air knives 410, 420 in the conveyance direction 102 of the glass sheet 30. The first fluid bearings 440 are located so as to support opposite faces 32, 34 of the glass sheet 30. The first fluid bearings 440 may include water or liquid bearings to support the glass sheet 30. The second fluid bearings 450 are located downstream of the air knives 410, 420 in the conveyance direction 102. The second fluid bearings 540 are located so as to support opposite faces 32, 34 of the glass sheet 30, and may include air bearings. The distance 460, parallel to the conveyance direction 102 of the glass sheet, between the first and second fluid bearings 440, 450 leaves an unsupported length of the glass sheet 30. See FIG. 6. In general, if the distance 460 is too large, then the glass sheet 30 may vary too much from a central portion of the conveyance path 100 between the air knives 410, 420 so as to produce unwanted differential drying, i.e., different drying conditions on opposite sides of the glass sheet 30. Additionally, the distance 460 can be controlled together with the difference in pressure between the air knives 410, 420, so as to avoid excessive vibration of the glass sheet 30. If the vibration becomes excessive, the glass sheet 30 may undesirably stick to an air knife 410, 420, undergo unwanted contact with the surrounding structures, and/or may be subject to breakage. For example, the distance 460 between first bearings 440 and second bearings 450 can be < about 75 mm, preferably < about 40 mm, and more preferably < about 25 mm. In general, a shorter distance 460 can be used with a higher difference in pressure between the air knives 410, 420 without causing excessive vibration in the glass sheet 30. Similarly, a longer distance 460 can be used with a lower difference in pressure between the air knives 410, 420 without causing excessive vibration in the glass sheet 30. More specifically, at one end of the spectrum, with a distance 460 of about 75 mm, the difference in pressure can be up to about 300 Pa. On the other end of the spectrum, with a distance 460 of about 25 mm or about 40 mm, the difference in pressure can be up to about 1500 Pa, for example, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, or 1400 Pa. In one embodiment, the distance 460 can be about 40 mm, and the difference in pressure between the air knives 410, 420 may be about 300 Pa. In another embodiment, the distance 460 can be about 25 mm, and the difference in pressure between the air knives 410, 420 may be about 300 Pa.

[0053] Additionally, in the drying section 400, there are provided pipes 430 having nozzles thereon. The pipes 430 may be connected to a fluid source to direct fluid toward the glass sheet 30 just before the glass sheet 30 is conveyed past the air knives 410, 420. [0054] Further, in the drying section, there are provided guide rollers 470 to support the top of the glass sheet. The guide rollers 470 are idle rollers, and provide additional support to the top of the glass sheet 30, i.e., the portion of the glass sheet 30 above the first and second bearings 440, 460. The location of the guide rollers 470 is important to avoid any damage in the quality area, and maintain effective conveyance, of the glass sheet 30. Accordingly, the guide rollers 470 are positioned to contact only the non-quality area of the glass sheet 30, which is a section around the perimeter of the glass sheet 30, extending in from each edge typically from about 5 to 10 mm.

[0055] Although the drying section 400 is shown as being connected to the outlet of the rinsing section 300, the drying section 400 can be used as a stand-alone unit. Additionally, other apparatuses and/or processes may be disposed between the rinsing section 300 and the drying section 400. Similarly, the washing 200 and rinsing 300 sections may be separated from one another and used as stand-alone units, whereby other apparatuses and/or processes may be disposed therebetween.

[0056] Although several embodiments of the invention have been disclosed in the foregoing specification, as may be understood by those skilled in the art, many modifications and other embodiments of the invention will come to mind to which the invention pertains, having the benefit of the teaching presented in the foregoing description and associated drawings. It is thus understood that the invention is not limited to the specific embodiments disclosed hereinabove, and that many modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although specific terms are employed herein, as well as in the claims which follow, they are used only in a generic and descriptive sense, and not for the purposes of limiting the invention, nor the claims which follow.

Claims

CLAIMSWe claim:

1. A glass treatment apparatus for treating a substantially planar glass sheet having a first face and an opposed second face, the glass treatment apparatus comprising a washing section comprising: a conveyance path, along which the glass sheet is capable of traveling in a substantially vertical plane; a first drive roller having a thickness and a diameter, and positioned adjacent the conveyance path so as to be capable of contacting a portion of the first face of the glass sheet; a second drive roller having a thickness and a diameter, and positioned adjacent the conveyance path so as to be capable of contacting a portion of the second face of the glass sheet, wherein the thickness of each one of the first and second drive rollers is from about 0.5 inches to about 2 inches, and wherein the diameter of each one of the first and second drive rollers is about 4 inches or less.

2. The apparatus of claim 1 , wherein the first drive roller and the second drive roller are disposed opposite to one another and are separated from one another by a gap.

3. The apparatus of claim 2, wherein the glass sheet has a thickness, and wherein the gap is less than the thickness of the glass sheet.

4. The apparatus of claim 1, wherein at least an external portion of each of the first and second drive rollers comprises a polymerized rubber.

5. The apparatus of claim 4, wherein the polymerized rubber comprises ethylene propylene diene monomer or Santoprene rubber.

6. The apparatus of claim 4, wherein the polymerized rubber has a hardness from about 30 Shore A to about 60 Shore A.

7. A glass treatment apparatus for treating a substantially planar glass sheet having a first face and an opposed second face, the glass treatment apparatus comprising a rinsing section comprising: a conveyance path, along which the glass sheet is capable of traveling in a substantially vertical plane; a first rinse nozzle positioned adjacent to the conveyance path and in communication with a liquid source, wherein the first rinse nozzle is positioned to be capable of directing liquid toward the first face of the glass sheet; and a first liquid bearing positioned adjacent the conveyance path so as to be capable of facing the second face of the glass sheet and to be substantially opposite the first rinse nozzle.

8. The apparatus of claim 7, further comprising: a second rinse nozzle positioned substantially adjacent the conveyance path and in communication with the liquid source, wherein the second rinse nozzle is positioned to be capable of directing liquid toward the second face of the glass sheet; and a second liquid bearing positioned adjacent the conveyance path so as to be capable of facing the first face of the glass sheet and to be substantially opposite the second rinse nozzle.

9. The apparatus of claim 8, wherein the second rinse nozzle is adjacent to the first liquid bearing, and the second liquid bearing is adjacent to the first rinse nozzle.

10. The apparatus of claim 8, wherein the first and second rinse nozzles are connected to a liquid supply source so that liquid is directed at the first and second faces of the glass sheet at a rate of from about 0.2 to about 2 GPM per nozzle, and wherein the liquid is directed at the first and second faces of the glass sheet with a pressure from about 10 to 50 psi.

11. The apparatus of claim 10, wherein the liquid causes the glass sheet to vibrate about 50 microns or less.

12. The apparatus of claim 7, wherein the glass treatment apparatus further comprises a washing section, the washing section comprising: a continuation of the conveyance path, along which the glass sheet is capable of traveling in a substantially vertical plane; a first drive roller having a thickness and a diameter, and positioned adjacent the conveyance path so as to be capable of contacting a portion of the first face of the glass sheet; a second drive roller having a thickness and a diameter, and positioned adjacent the conveyance path so as to be capable of contacting a portion of the second face of the glass sheet, wherein the thickness of each one of the first and second drive rollers is from about 0.5 inches to about 2 inches, and wherein the diameter of each one of the first and second drive rollers is about 4 inches or less.

13. A glass treatment apparatus for treating a substantially planar glass sheet having a first face and an opposed second face, the glass treatment apparatus comprising a drying section comprising: a conveyance path, along which the glass sheet is capable of traveling in a substantially vertical plane and in a conveyance direction; a first air knife positioned substantially adjacent the conveyance path, in communication with a gas source, and configured to direct gas at a first pressure toward the first face of the glass sheet; a second air knife positioned substantially adjacent the conveyance path, in communication with a gas source, and configured to direct gas at a second pressure toward the second face of the glass sheet, wherein the second air knife is positioned substantially opposite the first air knife; a first bearing positioned upstream of the first and second air knives, in the conveyance direction, and being configured and arranged to support the first face of the substantially planar glass sheet; and a second bearing positioned downstream of the first and second air knives, in the conveyance direction, and being configured and arranged to support the first face of the substantially planar glass sheet, wherein the first bearing and the second bearing are spaced from one another in the conveyance direction by a distance, wherein the distance is about 75mm or less, and wherein an absolute value of a difference between the first pressure and the second pressure is about 1500 Pa or less.

14. The apparatus of claim 13, wherein the distance is about 40 mm or less.

15. The apparatus of claim 14, wherein the absolute value of the difference between the first pressure and the second pressure is about 300 Pa or less.

16. The apparatus of claim 13, wherein the distance is about 25 mm or less.

17. The apparatus of claim 13, wherein the absolute value of the difference between the first pressure and the second pressure is about 300 Pa or less.

18. The apparatus of claim 13, further comprising a washing section, the washing section comprising: a continuation of the conveyance path, along which the glass sheet is capable of traveling in a substantially vertical plane; a first drive roller having a thickness and a diameter, and positioned adjacent the conveyance path so as to be capable of contacting a portion of the first face of the glass sheet; a second drive roller having a thickness and a diameter, and positioned adjacent the conveyance path so as to be capable of contacting a portion of the second face of the glass sheet, wherein the thickness of each one of the first and second drive rollers is from about 0.5 inches to about 2 inches, and wherein the diameter of each one of the first and second drive rollers is about 4 inches or less.

19. The apparatus of claim 13, further comprising a rinsing section, the rinsing section comprising: a continuation of the conveyance path, along which the glass sheet is capable of traveling in a substantially vertical plane; a first rinse nozzle positioned adjacent to the conveyance path and in communication with a liquid source, wherein the first rinse nozzle is positioned to direct liquid toward the first face of the glass sheet; and a first liquid bearing positioned adjacent the conveyance path so as to face the second face of the glass sheet and to be substantially opposite the first rinse nozzle.

20. The apparatus of claim 19, further comprising a washing section, the washing section comprising: a continuation of the conveyance path, along which the glass sheet is capable of traveling in a substantially vertical plane; a first drive roller having a thickness and a diameter, and positioned adjacent the conveyance path so as to be capable of contacting a portion of the first face of the glass sheet; a second drive roller having a thickness and a diameter, and positioned adjacent the conveyance path so as to be capable of contacting a portion of the second face of the glass sheet, wherein the thickness of each one of the first and second drive rollers is from about 0.5 inches to about 2 inches, and wherein the diameter of each one of the first and second drive rollers is about 4 inches or less.

21. A process for finishing a substantially planar glass sheet having a first face and an opposed second face, comprising: conveying the glass sheet, in a substantially vertical plane along a conveyance path, through at least one of a washing section, a rinsing section, and a drying section, in the event that the conveying includes conveying through the washing section, the method comprising: contacting the glass sheet with a first drive roller and a second drive roller to convey the sheet, wherein the first drive roller has a thickness and a diameter, and being positioned adjacent the conveyance path so as to be capable of contacting a portion of the first face of the glass sheet; and the second drive roller having a thickness and a diameter, and being positioned adjacent the conveyance path so as to be capable of contacting a portion of the second face of the glass sheet, wherein the thickness of each one of the first and second drive rollers is from about 1.27 cm to about 5.08 cm, and wherein the diameter of each one of the first and second drive rollers is about 10.16 cm or less; in the event that the conveying includes conveying through the rinsing section, the method comprising: directing liquid toward the glass sheet with first and second rinse nozzles while holding the glass sheet with first and second liquid bearings, wherein the first rinse nozzle is positioned adjacent to the conveyance path and is in communication with a liquid source so that the first rinse nozzle directs liquid toward the first face of the glass sheet; the first liquid bearing is positioned adjacent the conveyance path so that the first liquid bearing faces the second face of the glass sheet and is substantially opposite the first rinse nozzle; the second rinse nozzle is positioned substantially adjacent the conveyance path and is in communication with the liquid source so that the second rinse nozzle directs liquid toward the second face of the glass sheet; and the second liquid bearing is positioned adjacent the conveyance path so that the second liquid bearing faces the first face of the glass sheet and is substantially opposite the second rinse nozzle; in the event that the conveying includes conveying the glass sheet through the drying section, the method comprising: supporting the glass sheet with first and second bearings; and directing gas toward the glass sheet with first and second air knives, wherein the first air knife is positioned substantially adjacent the conveyance path, is in communication with a gas source, and directs gas at a first pressure toward the first face of the glass sheet; the second air knife is positioned substantially adjacent the conveyance path, is in communication with a gas source, and directs gas at a second pressure toward the second face of the glass sheet, wherein the second air knife is positioned substantially opposite the first air knife; the first bearing is positioned upstream of the first and second air knives, in the conveyance direction, and is configured and arranged to support the first face of the substantially planar glass sheet; and the second bearing is positioned downstream of the first and second air knives, in the conveyance direction, and is configured and arranged to support the first face of the substantially planar glass sheet, wherein the first bearing and the second bearing are spaced from one another in the conveyance direction by a distance, wherein the distance is about 75mm or less, and wherein an absolute value of a difference between the first pressure and the second pressure is about 1500 Pa or less.

22. The method of claim 1, further comprising directing liquid at the first and second faces of the glass sheet at a rate of from about 757 to about 7571 ccm per nozzle, and with a pressure from about 68950 to about 344738 N/m².

23. The method of claim 1 , wherein the distance is about 40 mm or less.

24. The method of claim 1 , wherein the distance is about 25 mm or less.

25. The method of claim 1, claim 3, or claim 4, wherein the absolute value of the difference between the first pressure and the second pressure is about 300 Pa or less.