US3690917A - Suction system and process for coating arrangements avoiding the transmission of pressure differences to the coating operation - Google Patents

Suction system and process for coating arrangements avoiding the transmission of pressure differences to the coating operation Download PDF

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Publication number
US3690917A
US3690917A US8262A US3690917DA US3690917A US 3690917 A US3690917 A US 3690917A US 8262 A US8262 A US 8262A US 3690917D A US3690917D A US 3690917DA US 3690917 A US3690917 A US 3690917A
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United States
Prior art keywords
coating
vacuum chamber
air
transmission
avoiding
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Expired - Lifetime
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US8262A
Inventor
Peter Herzhoff
Stephan Platz
Hans Gref
Willi Schwenger
Fritz Maus
Wolfgang Schweicher
Gunther Koepke
Willi Wasser
Kurt Browatzki
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Agfa Gevaert AG
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Agfa Gevaert AG
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    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06B—TREATING TEXTILE MATERIALS USING LIQUIDS, GASES OR VAPOURS
    • D06B15/00—Removing liquids, gases or vapours from textile materials in association with treatment of the materials by liquids, gases or vapours
    • D06B15/09—Removing liquids, gases or vapours from textile materials in association with treatment of the materials by liquids, gases or vapours by jets of gases
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C1/00—Photosensitive materials
    • G03C1/74—Applying photosensitive compositions to the base; Drying processes therefor

Definitions

  • a photographic web is coated with a photographic emulsion under a roller and the inal thickness of the coating is eiected by an air stream blown tangentially over the coating into a vacuum chamber. Pluctuations in the air stream are prevented by subjecting the air stream discharged from the vacuum chamber to a sudden restriction in its cross sectional area by passing it through an apertured diaphragm. This abruptly changes its pressure in the ratio of at least 2:1 and obtains relatively high air velocity in the aperture in the sonic region.
  • This invention relates to a method and a suction system for coating arrangements, for avoiding the transmission of pressure differences in the suction system to the coating operation.
  • the invention is particularly applicable when coating webs, more especially with photographic emulsions, the web being initially coated in a wedge-like gap and the tinal coating eiected by means of an oppositely directed air stream substantially tangential to the coating direction, said air stream blowing through a gap-forming straight edge into a vacuum chamber, from which chamber the air is drawn oif by suction.
  • an adjustable diaphragm is arranged in the air suction pipe.
  • a web 1 to be coated is moved in the direction of the arrow over a roller 2.
  • the emulsion is supplied through supply pipe 3 and distributor system 4.
  • a component stream discharges again over the rear overflow edge 5 and the pipe 6.
  • the other part is preformed into a layer in a preproportioning wedge 7, but this layer is thicker than the layer finally to be formed.
  • the nished layer or coating is formed at a gap 8 between the web 1 and the so-called casting straight edge 9 by the stripping action of the blowing air flowing tangentially to the web 1 into the vacuum chamber 10, 12.
  • the air is deiiected immediately after the straight edge 9 and is drawn by suction through the constriction 11 into the chamber 12 through the connecting pipe 13, the sudden pressure change being produced in the opening of diaphragm 14.
  • the emulsion which is blown off discharges through the pipe 15.
  • a method of applying a .photographic emulsion coating to webs which avoids the transmission of pressure fluctuations in the suction system of coating arrangements, comprising the steps of coating the web under a roller with an excess of coating and effecting the iinal coating by means of an air stream directed substantially tangentially and counter to the roller coating direction, blowing the air stream over a gap-forming straight edge into a vacuum chamber, from which chamber the air is extracted by a suction device, wherein before entering the suction device, subjecting the blowing air extracted by the vacuum chamber to a sudden restriction in its cross-sectional ow area while being discharged from said vacuum chamber causing a pressure change in said discharged air in the ratio of at least 2:1 whereby its velocity is increased to approximately sonic speed and whereby pressure iiuctuations in the air stream are prevented and smooth uniform coating is effected upon said web.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)

Abstract

A PHOTOGRAPHIC WEB IS COATED WITH A PHOTOGRAPHIC EMULSION UNDER A ROLLER AND THE FINAL THICKNESS OF THE COATING IS EFFECTED BY AN AIR STREAM BLOWN TANGENTIALLY OVER THE COATING INTO A VACUUM CHAMBER. FLUCTUATIONS IN THE AIR STREAM ARE PREVENTED BY SUBJECTING THE AIR DISCHARGED FROM THE VACUUM CHAMBER TO A SUDDEN RESTRICTION IN ITS CROSS SECTIONAL AREA BY PASSING IT THROUGH AN APERTURED DIAPHRAGM. THIS ABRUPTLY CHANGES ITS PRESSURE IN THE RATIO OF AT LEAST 2:1 AND OBTAINS RELATIVELY HIGH AIR VELOCITY IN THE APERTURE IN THE SONIC REGION.

Description

Sept. 12, 1972 P. HERsHoFF HAL 3,690,917
SUCTION SYSTEM AND PROCESS FOR COATING ARRANGEMENTS AVOIDING` THE TRANSMISSION OF PRESSURE DIFFERENCES TO THE COATING OPERATION Filed Feb. 5, 1970 INVENTOR:
PETER HEHZHOFF, HANS GEEF, WILLI SCHWENGER, WOLFGANG SCHWECHER, KURT BhO'v'VA'l"ZKI, STEPHAN PLATZ, GNTHER KOEPE,
""'f MAUS, WlLLI WALiSEh.
United States Patent O U.S. Cl. 117-34 2 Claims ABSTRACT OF THE DISCLOSURE A photographic web is coated with a photographic emulsion under a roller and the inal thickness of the coating is eiected by an air stream blown tangentially over the coating into a vacuum chamber. Pluctuations in the air stream are prevented by subjecting the air stream discharged from the vacuum chamber to a sudden restriction in its cross sectional area by passing it through an apertured diaphragm. This abruptly changes its pressure in the ratio of at least 2:1 and obtains relatively high air velocity in the aperture in the sonic region.
This invention relates to a method and a suction system for coating arrangements, for avoiding the transmission of pressure differences in the suction system to the coating operation. The invention is particularly applicable when coating webs, more especially with photographic emulsions, the web being initially coated in a wedge-like gap and the tinal coating eiected by means of an oppositely directed air stream substantially tangential to the coating direction, said air stream blowing through a gap-forming straight edge into a vacuum chamber, from which chamber the air is drawn oif by suction.
With coating arrangements of known design, it has been found that fluctuations in pressure in the suction system have a disadvantageous effect on the coating operation, since the speed of the tangential blowing air stream also iluctuates in synchronism with the pressure fluctuations, and leads to a non-uniform coating, which is shown in the form of uetuations in thickness, so-called transverse streaks.
It has now been found that these disturbing pressures are avoided by the blowing air extracted from the vacuum chamber being guided by an apertured diaphragm before entering the suction arrangement, a critical pressure increase in the ratio of at least 2:1 being thus produced.
The result thereby achieved is that sonic speed obtains in the diaphragm aperture and all pressure waves which emanate from exciting devices behind the diaphragm are taken up in the diaphragm aperture, so that the actual coating position remains free from pressure uctuations and a uniform coating is guaranteed.
According to the invention, in the suction extraction system of coating arrangements for carrying out the method, an adjustable diaphragm is arranged in the air suction pipe.
The essential feature of the invention is now to be explained by reference to an example shown in the drawing.
A web 1 to be coated is moved in the direction of the arrow over a roller 2. The emulsion is supplied through supply pipe 3 and distributor system 4. A component stream discharges again over the rear overflow edge 5 and the pipe 6. The other part is preformed into a layer in a preproportioning wedge 7, but this layer is thicker than the layer finally to be formed. The nished layer or coating is formed at a gap 8 between the web 1 and the so-called casting straight edge 9 by the stripping action of the blowing air flowing tangentially to the web 1 into the vacuum chamber 10, 12. The air is deiiected immediately after the straight edge 9 and is drawn by suction through the constriction 11 into the chamber 12 through the connecting pipe 13, the sudden pressure change being produced in the opening of diaphragm 14. The emulsion which is blown off discharges through the pipe 15.
We claim:
1. A method of applying a .photographic emulsion coating to webs which avoids the transmission of pressure fluctuations in the suction system of coating arrangements, comprising the steps of coating the web under a roller with an excess of coating and effecting the iinal coating by means of an air stream directed substantially tangentially and counter to the roller coating direction, blowing the air stream over a gap-forming straight edge into a vacuum chamber, from which chamber the air is extracted by a suction device, wherein before entering the suction device, subjecting the blowing air extracted by the vacuum chamber to a sudden restriction in its cross-sectional ow area while being discharged from said vacuum chamber causing a pressure change in said discharged air in the ratio of at least 2:1 whereby its velocity is increased to approximately sonic speed and whereby pressure iiuctuations in the air stream are prevented and smooth uniform coating is effected upon said web.
2. A method as set forth in claim 1 wherein said restriction is abruptly obtained.
References Cited UNITED STATES PATENTS 3,348,964 10/ 1967 Good 118-50 2,681,294 6/ 1954 Beguin 117-34 3,227,136 1/ 1966 Bartlett et al. 118-63 2,952,559 9/ 1960 Nadeau 117-34 3,503,370 3/ 1970 Ishwata 117-34 3,502,494 3/1970 Ishiwata 117-34 WILLIAM D. MARTIN, Primary Examiner W. R. TRENOR, Assistant Examiner U.S. Cl. X.R. 117-61, 111, 119; 118-7, 50, 63, 410
-PO-OSO UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,690. 917 Dated September l2, 1972 Inventoms) Peter Herzhoff et al Itis certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
[ On the cover page, in the heading, change l HERSHOFF ET AL" tO HERZHOFF ET AL Signed and Sealed this 13th day of February 1973 (SEAL) Attest:
EDWARD M. FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents
US8262A 1970-02-03 1970-02-03 Suction system and process for coating arrangements avoiding the transmission of pressure differences to the coating operation Expired - Lifetime US3690917A (en)

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3937177A (en) * 1974-03-07 1976-02-10 Versatec, Inc. Electrostatic printing machine with improved toner fountain and recovery system
US3996889A (en) * 1974-04-11 1976-12-14 Agfa-Gevaert, A.G. Apparatus for coating web-form substrates with liquid solution or dispersions
US4257343A (en) * 1973-11-16 1981-03-24 Billeruds Aktiebolag Coating apparatus with vacuum biased doctor blade
US4292349A (en) * 1978-12-06 1981-09-29 Fuji Photo Film Co., Ltd. Coating method and apparatus
US5354376A (en) * 1992-03-11 1994-10-11 Institute Of Paper Science And Technology Flotation coating device for traveling webs
US5366551A (en) * 1992-03-11 1994-11-22 Institute Of Paper Science And Technology, Inc. Coating device for traveling webs
US5456944A (en) * 1991-10-15 1995-10-10 Eastman Kodak Company Magnetic dispersion coating method having high shear regions
US5618568A (en) * 1995-02-01 1997-04-08 Extrusion Dies, Inc. Dual-chamber vacuum box
US5728429A (en) * 1994-08-13 1998-03-17 Glyco-Metall-Werke Gkyco B.V. & Co. Kg Method and a device for producing thin layers from liquids to form coating or foils
US5780109A (en) * 1997-01-21 1998-07-14 Minnesota Mining And Manufacturing Company Die edge cleaning system
US5820674A (en) * 1996-08-16 1998-10-13 Institute Of Paper Science And Technology, Inc. Vortex-free coating device for traveling webs
US5843530A (en) * 1997-01-21 1998-12-01 Minnesota Mining And Manufacturing Company Method for minimizing waste when coating a fluid with a slide coater
US5849363A (en) * 1997-01-21 1998-12-15 Minnesota Mining And Manufacturing Company Apparatus and method for minimizing the drying of a coating fluid on a slide coater surface
US5861195A (en) * 1997-01-21 1999-01-19 Minnesota Mining And Manufacturing Company Method for coating a plurality of fluid layers onto a substrate
US20080295765A1 (en) * 2007-05-31 2008-12-04 Tdk Corporation Liquid applicator

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4257343A (en) * 1973-11-16 1981-03-24 Billeruds Aktiebolag Coating apparatus with vacuum biased doctor blade
US3937177A (en) * 1974-03-07 1976-02-10 Versatec, Inc. Electrostatic printing machine with improved toner fountain and recovery system
US3996889A (en) * 1974-04-11 1976-12-14 Agfa-Gevaert, A.G. Apparatus for coating web-form substrates with liquid solution or dispersions
US4292349A (en) * 1978-12-06 1981-09-29 Fuji Photo Film Co., Ltd. Coating method and apparatus
US5456944A (en) * 1991-10-15 1995-10-10 Eastman Kodak Company Magnetic dispersion coating method having high shear regions
US5582645A (en) * 1991-10-15 1996-12-10 Eastman Kodak Company Magnetic dispersion coating apparatus having high shear regions
US5354376A (en) * 1992-03-11 1994-10-11 Institute Of Paper Science And Technology Flotation coating device for traveling webs
US5366551A (en) * 1992-03-11 1994-11-22 Institute Of Paper Science And Technology, Inc. Coating device for traveling webs
US5728429A (en) * 1994-08-13 1998-03-17 Glyco-Metall-Werke Gkyco B.V. & Co. Kg Method and a device for producing thin layers from liquids to form coating or foils
US5618568A (en) * 1995-02-01 1997-04-08 Extrusion Dies, Inc. Dual-chamber vacuum box
US5820674A (en) * 1996-08-16 1998-10-13 Institute Of Paper Science And Technology, Inc. Vortex-free coating device for traveling webs
US5780109A (en) * 1997-01-21 1998-07-14 Minnesota Mining And Manufacturing Company Die edge cleaning system
US5843530A (en) * 1997-01-21 1998-12-01 Minnesota Mining And Manufacturing Company Method for minimizing waste when coating a fluid with a slide coater
US5849363A (en) * 1997-01-21 1998-12-15 Minnesota Mining And Manufacturing Company Apparatus and method for minimizing the drying of a coating fluid on a slide coater surface
US5861195A (en) * 1997-01-21 1999-01-19 Minnesota Mining And Manufacturing Company Method for coating a plurality of fluid layers onto a substrate
US6007874A (en) * 1997-01-21 1999-12-28 Minnesota Mining And Manufacturing Company Method for coating a plurality of fluid layers onto a substrate
US6200641B1 (en) 1997-01-21 2001-03-13 3M Innovative Properties Company Method for coating a plurality of fluid layers onto a substrate
US6214111B1 (en) 1997-01-21 2001-04-10 3M Innovative Properties Company Die edge cleaning system
US6458422B2 (en) 1997-01-21 2002-10-01 3M Innovative Properties Company Method for coating a plurality of fluid layers onto a substrate
US6458421B2 (en) 1997-01-21 2002-10-01 3M Innovative Properties Company Method for coating a plurality of fluid layers onto a substrate
US20080295765A1 (en) * 2007-05-31 2008-12-04 Tdk Corporation Liquid applicator
US8020510B2 (en) * 2007-05-31 2011-09-20 Tdk Corporation Coating die having front and back concave surfaces corresponding to narrow central angles of the guide roll

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