Source: http://www.google.com/patents/US5820674?ie=ISO-8859-1
Timestamp: 2015-04-25 13:49:16
Document Index: 800402626

Matched Legal Cases: ['art 1', 'art 2', 'art 3', 'art 1', 'art 2', 'art 3']

Patent US5820674 - Vortex-free coating device for traveling webs - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsCoating devices for application of coating material to the surface of a web or a flexible substrate utilizing the study of flow patterns in blade coating to develop high-speed coaters, wherein the coater may be modified to provide an air layer between the coating liquid and any lower boundary. The coater...http://www.google.com/patents/US5820674?utm_source=gb-gplus-sharePatent US5820674 - Vortex-free coating device for traveling websAdvanced Patent SearchPublication numberUS5820674 APublication typeGrantApplication numberUS 08/699,155Publication dateOct 13, 1998Filing dateAug 16, 1996Priority dateAug 16, 1996Fee statusLapsedAlso published asCA2262485A1, EP0918571A1, EP0918571A4, WO1998006504A1Publication number08699155, 699155, US 5820674 A, US 5820674A, US-A-5820674, US5820674 A, US5820674AInventorsCyrus K. AidunOriginal AssigneeInstitute Of Paper Science And Technology, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (22), Non-Patent Citations (20), Referenced by (3), Classifications (13), Legal Events (8) External Links: USPTO, USPTO Assignment, EspacenetVortex-free coating device for traveling webs
US 5820674 AAbstract
Coating devices for application of coating material to the surface of a web or a flexible substrate utilizing the study of flow patterns in blade coating to develop high-speed coaters, wherein the coater may be modified to provide an air layer between the coating liquid and any lower boundary. The coater devices of the described embodiments provide two inlet channels and an outlet channel. The first inlet channel carries the coating liquid, and the second channel can be used to pump the carrier fluid, e.g. air, into the coating head to pressurize the chamber and to keep the contact wetting line at the upstream section attached to the substrate. The air layer serves as a carrier fluid removing the wall shear stress on the coating liquid in the channel, and thus the coating flow for the operation of the device may proceed without flow separation from the wall (i.e., in a vortex-free mode) at relatively low flow rates appropriate for commercial applications. The excess coating liquid and all of the air leave the coater head at the outlet channel. A coating composition application chamber receives the liquid flow of the liquid coating composition from the upstream direction to the downstream direction. The coating composition application chamber is adapted for receiving a liquid flow of a carrier fluid introduced at the upstream side of the application chamber in the direction of the travel of the web positioning the liquid flow of the liquid coating composition between the carrier fluid and the web.
1. A coating device for applying a liquid coating composition on a web of material as the web travels along a web path through the device from an upstream direction to a downstream direction, the device comprising:a doctor element spaced from the web for spreading and defining the thickness of the liquid coating composition on the web, the doctor element extending across the web path; a coating composition application chamber adapted for receiving a liquid flow of the liquid coating composition from the upstream direction to the downstream direction, the application chamber extending across the web path, the application chamber having upstream and downstream sides with the web adapted to travel along the web path from the upstream side to the downstream side of the application chamber, the coating application chamber comprising in cross-section, an upstream interior side wall, an upstream boundary wall and the doctor element, the coating composition application chamber further comprising a first channel for receiving a flow of the liquid coating composition at the upstream interior side wall, and a gas channel for receiving a flow of a carrier gas as a gas layer introduced through said gas channel which terminates adjacent said first channel at the upstream side of the application chamber, the gas from the gas channel interfacing the coating composition, the flow of the liquid coating composition and the flow carrier gas traveling in the direction of the travel of the web, the flow of the carrier gas in direct contact with the coating composition and supporting the liquid flow of the liquid coating composition between the gas layer and the web, the gas layer opposite the web defining a top interior gas layer wall and the gas layer opposite the doctor blade defining a downstream interior gas layer wall, the upstream boundary wall and the upstream interior wall being substantially parallel to the other and each having a terminating curvilinear section which are substantially parallel to the other, the upstream boundary wall adapted to terminate in tangential relation with the web path, the top interior gas layer wall substantially conveying the liquid coating composition from the terminating curvilinear section of the upstream interior wall in the direction of the travel of the web to the downstream interior gas layer wall and doctor element, the upstream walls, the top interior gas layer wall and web, the downstream interior gas layer wall and doctor element define a path in which a flowing stream of the liquid coating composition flows downstream in the direction of travel of the web, the flow of carrier gas reducing wall shear stress on the flowing stream of the liquid coating composition and reducing the formation of recirculating eddies and vortices in the coating composition as the coating composition flows downstream through the coating application chamber. 2. A coating device in accordance with claim 1 wherein the carrier gas comprises air pumped into the coating application chamber maintaining the liquid coating composition in contact with the web under pressure at least at the upstream side of the application chamber preventing air entrainment as the coating composition is introduced to the web.
The present invention relates generally to a coating device for uniform coating of a traveling web of material. More particularly, the present invention relates to a pressurized coater which eliminates the captive pond associated with pressurized pond coaters, and provides the coating material in the form of a flowing stream of liquid coating composition which flows in the same direction as the web movement in a vortex-free coater reducing wall shear stress on the coating material.
One of the most significant changes in light weight coated (LWC) paper production is the use of the pressurized pond coater. The pressurized pond coater such as short-dwell coaters has enabled the paper maker to improve productivity while maintaining coated paper quality. The term "short-dwell" refers to the relatively short period of time that the coating is in contact with a web of paper material before the excess is metered off by a trailing doctor blade. Prior art short-dwell coaters consist of a captive pond just prior to a doctor blade. The pond is approximately 5 cm in length and is slightly pressurized to promote adhesion of the coating to the paper web. The excess coating supplied to the sheet creates a backflow of coating. This coating backflow provides a wetting line and thus, to some extent, excludes the boundary layer of air entering with the sheet and eliminates skip coating. The excess coating is typically channeled over an overflow baffle and collected in a return pan before returning to tanks to be screened.
The invention relates to coating devices for application of coating material to the surface of a web or a flexible substrate. Such coating devices employ a pressurized channel where a flowing stream of the coating liquid comes into contact with the substrate. The coating liquid first enters at the upstream side of the channel wetting the substrate as it flows in the same direction with the substrate. A doctor element is positioned at the downstream side of the channel where the excess coating in the channel follows the contour of the boundary formed by the doctor element and leaves the channel.
FIG. 1 is a schematic cross-sectional view of an embodiment of a short-dwell coating device according to the invention;
As shown in FIG. 1A, the short-dwell coating device 10 of the present invention includes of a first continuous channel 12 for receiving a liquid coating composition material 14 which passes through a coating application chamber 16 which is in contact with a roll or web 18 of material which is to be coated. The coating device 10 further includes of a second continuous channel 20 for receiving a liquid flow of a carrier fluid such as air 22 which also passes through a coating application chamber 16 positioning the liquid flow of the liquid coating composition 14 between the carrier fluid 22 and the web 18 of material which is to be coated. For purposes of orientation and discussion, the coating chamber has an upstream side and a downstream side with respect to movement of the web with the upstream side being to the left of FIG. 1A. The use of the terms "horizontal" and "vertical" are with respect to a horizontal orientation of the web 18. The web 18, however, is usually supported on a counter roll and has a slight curvature in the region of the coating application chamber 16.
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Aidun, "Principles of Hydrodynamic Instanbility: Application on Coating Systems; Part 3. A Generalized View of Instability and Bifurcation," reprinted from TAPPI Journal, vol. 74, No. 4, pp. 209-213, Apr., 1991.4Cyrus K. Aidun, N. G. Triantafillopoulos and J. D. Benson, "Global Stability of a Lid-Driven Cavity With Throughflow: Flow Visualization Studies," from Phys. Fluids A, vol. 3, No. 9, American Institute of Physics, pp. 2081-2091, Sep., 1991.5 *Cyrus K. Aidun, N. G. Triantafillopoulos and J. D. Benson, Global Stability of a Lid Driven Cavity With Throughflow: Flow Visualization Studies, from Phys. Fluids A , vol. 3, No. 9, American Institute of Physics, pp. 2081 2091, Sep., 1991.6 *Cyrus K. Aidun, Principles of Hydrodynamic Instability: Application on Coating Systems; Part 1. Background, reprinted from TAPPI Journal , vol. 74, No. 2, pp. 213 219, Feb., 1991.7 *Cyrus K. Aidun, Principles of Hydrodynamic Instability: Application on Coating Systems; Part 2. Examples of Flow Instability, reprinted from TAPPI Journal , vol. 74, No. 3, pp. 213 220, Mar., 1991.8 *Cyrus K. Aidun, Principles of Hydrodynamic Instanbility: Application on Coating Systems; Part 3. A Generalized View of Instability and Bifurcation, reprinted from TAPPI Journal , vol. 74, No. 4, pp. 209 213, Apr., 1991.9E. W. Wight, "Modern Coating Application and Blade Metering Systems," from TAPPI Seminar Notes, 1986 Blade Coating, pp. 105-108.10 *E. W. Wight, Modern Coating Application and Blade Metering Systems, from TAPPI Seminar Notes , 1986 Blade Coating, pp. 105 108.11F. R. Pranckh & L. E. Scriven, "Elastohydrodynamics of Blade Coating," AIChE Journal, vol. 36, No. 4, pp. 587-597, Apr. 1990. (Best Copy).12 *F. R. Pranckh & L. E. Scriven, Elastohydrodynamics of Blade Coating, AIChE Journal , vol. 36, No. 4, pp. 587 597, Apr. 1990. (Best Copy).13Herbert Sommer, "Application Systems for Coating ULWC and MFP Papers," from TAPPI Proceedings, 1988 Coating Conference, pp. 131-137.14 *Herbert Sommer, Application Systems for Coating ULWC and MFP Papers, from TAPPI Proceedings , 1988 Coating Conference, pp. 131 137.15J. D. Benson and C. K. Aidun, "Transition to Unsteady Nonperiodic State in a Through-Flow Lid-Driven Cavity," from Phys. Fluids A, (Brief Communications) vol. 4, No. 10, American Institute of Physics, pp. 2316-2319, Oct., 1992.16 *J. D. Benson and C. K. Aidun, Transition to Unsteady Nonperiodic State in a Through Flow Lid Driven Cavity, from Phys. Fluids A , (Brief Communications) vol. 4, No. 10, American Institute of Physics, pp. 2316 2319, Oct., 1992.17N.G. Triantafillopoulos & C. K. Aidun, "Relationship Between Flow Instability in Short-Dwell Ponds and Cross Directional Coat Weight Nonuniformities," reprinted from TAPPI Journal, vol. 73, No. 6, pp. 127-136, Jun., 1990.18 *N.G. Triantafillopoulos & C. K. Aidun, Relationship Between Flow Instability in Short Dwell Ponds and Cross Directional Coat Weight Nonuniformities, reprinted from TAPPI Journal , vol. 73, No. 6, pp. 127 136, Jun., 1990.19 *Rudolph Beisswanger & Dr. Ing. Hans Peter Sollinger, Coating Paper and Board, Practical Experience with the SDTA and LDTA, from TAPPI Seminar Notes , 1986 Blade Coating, pp. 137 142.20Rudolph Beisswanger & Dr. Ing. Hans-Peter Sollinger, "Coating Paper and Board, Practical Experience with the SDTA and LDTA," from TAPPI Seminar Notes, 1986 Blade Coating, pp. 137-142.* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS6131416 *Feb 8, 1999Oct 17, 2000Lucent Technologies Inc.Bubble prevention in coating of filamentsUS6743478Sep 1, 2000Jun 1, 2004Metso Paper, Inc.Improvement in the reduction of the amount of boundary air penetration to the application zone of a curtain coater.WO2001016427A1 *Sep 1, 2000Mar 8, 2001Valmet CorpCurtain coater and method for curtain coating* Cited by examinerClassifications U.S. Classification118/410, 118/419International ClassificationB05D1/28, B05C11/04, B05C3/18, D21H23/36, B05C5/02Cooperative ClassificationD21H23/36, B05D1/28, B05C5/0254European ClassificationB05C5/02F, D21H23/36, B05D1/28Legal EventsDateCodeEventDescriptionNov 30, 2010FPExpired due to failure to pay maintenance feeEffective date: 20101013Oct 13, 2010LAPSLapse for failure to pay maintenance feesMay 17, 2010REMIMaintenance fee reminder mailedApr 7, 2006FPAYFee paymentYear of fee payment: 8Nov 15, 2004ASAssignmentOwner name: GEORGIA TECH RESEARCH CORPORATION, GEORGIAFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:INSTITUTE OF PAPER SCIENCE AND TECHNOLOGY, INC.;REEL/FRAME:015355/0685Effective date: 20041105Owner name: GEORGIA TECH RESEARCH CORPORATION 505 10TH STREETFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:INSTITUTE OF PAPER SCIENCE AND TECHNOLOGY, INC. /AR;REEL/FRAME:015355/0685Mar 21, 2002FPAYFee paymentYear of fee payment: 4Aug 10, 1999CCCertificate of correctionAug 16, 1996ASAssignmentOwner name: INSTITUTE OF PAPER SCIENCE AND TECHNOLOGY, INC., GFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:AIDUN, CYRUS K.;REEL/FRAME:008172/0544Effective date: 19960815RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services