EP0325021A2 - Zirkulationsvorrichtung und Verfahren um das Schäumen in der Anfeuchtvorrichtung einer Druckmaschine zu verhindern - Google Patents

Zirkulationsvorrichtung und Verfahren um das Schäumen in der Anfeuchtvorrichtung einer Druckmaschine zu verhindern Download PDF

Info

Publication number
EP0325021A2
EP0325021A2 EP88307801A EP88307801A EP0325021A2 EP 0325021 A2 EP0325021 A2 EP 0325021A2 EP 88307801 A EP88307801 A EP 88307801A EP 88307801 A EP88307801 A EP 88307801A EP 0325021 A2 EP0325021 A2 EP 0325021A2
Authority
EP
European Patent Office
Prior art keywords
wetting fluid
return conduit
orifice
outlet
venturi tube
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP88307801A
Other languages
English (en)
French (fr)
Other versions
EP0325021A3 (de
Inventor
Robert W. Macdonald
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Baldwin Technology Corp
Original Assignee
Baldwin Technology Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Baldwin Technology Corp filed Critical Baldwin Technology Corp
Publication of EP0325021A2 publication Critical patent/EP0325021A2/de
Publication of EP0325021A3 publication Critical patent/EP0325021A3/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F33/00—Indicating, counting, warning, control or safety devices
    • B41F33/0054—Devices for controlling dampening

Definitions

  • the present invention relates to the dampening systems of printing presses.
  • a dampening system is used to provide a thin layer of a wetting fluid to the press plates.
  • the wetting fluid is usually water, or a water, chemical and isopropanol mixture. Isopropanol is used to reduce the surface tension of the wetting fluid, allowing it to be spread more easily and thinly on the press plate.
  • the dampening system wets down the plate before the ink is applied to the plate to selectively prevent inking of the press plate.
  • the dampening system will include an open fountain pan having an inlet and an outlet through which flows a stream of the wetting fluid and in which rotates a water pan roller.
  • the water pan roller picks up a film of the wetting fluid and transfers this film to a contacting counter-rotating roller to make the film thinner; at least one more roller is usually used to further thin the wetting fluid before it is applied to a press plate.
  • the wetting fluid is drawn from the fountain pan through return tubing by suction which is created by a venturi in a cooling unit.
  • the wetting fluid is passed through a filter to remove lint, dust, fibers and ink from the wetting fluid, and then cooled in a refrigerated reservoir in the cooling unit.
  • the wetting fluid is then pumped from the reservoir to a flow divider which directs a portion of the wetting fluid back to the fountain pan, and a portion of the wetting fluid through the venturi to create suction in the return conduit.
  • the venturi has a single orifice at its throat sized to provide the maximum amount of vacuum for the pump flow rate.
  • a wetting fluid specific gravity measuring apparatus and isopropanol metering unit is provided between the pump outlet and the fountain pan to maintain a predetermined mixture of water and isopropanol in the wetting fluid.
  • the most severe problem of air entrainment in the circulation system is that it can cause foaming of the wetting fluid as it passes through the venturi and the filters.
  • Foam in the wetting fluid creates immediate print quality problems.
  • Foam in the dampening system, particularly in the fountain pan impedes the smooth dispersion of the wetting fluid on the press plate, giving unacceptably poor print quality.
  • the foam will cause false measurements in the wetting fluid specific gravity measurement apparatus.
  • the wetting fluid specific gravity measurement apparatus will be measuring a wetting fluid having a lower specific gravity due to the entrained bubbles in the wetting fluid, and will thus meter a lower quantity of isopropanol into the system than desired, causing a further deterioration in wetting fluid dispersion and print quality.
  • the fountain pan outlet size might be increased in diameter; however, this would involve expensive retrofitting of the existing press hardware.
  • a defoaming agent might be added to the wetting fluid; however, this could negatively affect the qualities of the etch solution.
  • a reduction of the wetting fluid flow rate can reduce the foaming in the system.
  • a reduced flow rate causes other problems.
  • the constant contact between the rotating rolls generates a great deal of frictional heat, which causes a substantial temperature differential in the wetting fluid between the inlet and outlet of the fountain pan.
  • This temperature differential in the wetting fluid from one end of the pan to the other causes a viscosity change in the wetting fluid as it passes through the pan. Consequently, more wetting fluid will be picked up by the pan rollers at the inlet side than at the outlet side of the pan, causing print quality variations.
  • the lower the flow rate of the wetting fluid through the fountain pan the more severe this problem becomes.
  • the uneven spreading associated with low wetting fluid flow rates may induce the pressman to increase the amount of isopropanol in the wetting fluid in an attempt to achieve better spreading of the wetting fluid.
  • high levels of isopropanol in the wetting fluid pose potential health problems for the pressmen, may violate emissions control standards, and increase fire and explosion hazards.
  • a circulation system which comprises a fountain pan having at each end an inlet and an outlet through which flows a wetting fluid.
  • a return conduit is attached to the fountain pan outlet; this return conduit has a vent downstream of the outlet which allows entrained air to escape from the conduit.
  • the return conduit has preferably at least a 5/8 inch inner diameter.
  • the vent is located between closely adjacent to up to about 24 inches downstream of the outlet, preferably in a vertical section of the conduit.
  • a tube which leads back up to and into the fountain pan may be mounted in the vent to recycle liquid to the fountain tray outlet.
  • a sump which may comprise a portion of the return conduit formed into an inverted U-shaped loop, may be provided downstream of the vent at the lowest point of the return conduit.
  • Wetting fluid is drawn from the sump and return conduit by a venturi tube, and flowed through a filter unit.
  • the venturi tube provides a vacuum to the sump which calibrated to be sufficient to draw wetting fluid from the sump, yet which does not entrain air into the wetting fluid at the fountain pan outlet.
  • the venturi tube has an inlet with a first orifice and a throat with a second orifice.
  • the return conduit is connected to the venturi downstream of the second orifice, and the vacuum created in the return conduit pulls the wetting fluid from the sump and return conduit.
  • the ratio of the inner diameter of the first orifice to the inner diameter of the second orifice is about 0.5 to 1.25.
  • a reservoir having a cooling means within it receives the wetting fluid from the filter.
  • a pump then flows the wetting fluid from the reservoir to a flow divider which sends a portion of the pumped fluid to the venturi to induce the vacuum in the return conduit, and a portion of the fluid back to the fountain tray inlet for application to the press plate.
  • the circulation system 10 comprises a standard fountain pan 20 having an inlet 22 and an outlet 24 at opposite ends of the fountain pan 20. Wetting fluid in the fountain pan is drained through outlet 24 into return conduit 26, which is typically a flexible tubing which preferably has an inner diameter of at least 5/8 inch to allow a downward fluid flow as well as a upward flow of any trapped air bubbles.
  • Vent 28 is located in return conduit 26. Vent 28 serves to vent air which is drawn into conduit 26 through the outlet 24, preventing air bubbles from becoming trapped in the conduit 26 and blocking the flow of the wetting fluid, and eliminating these bubbles from the circulation system before they are passed through a venturi tube 38 where they would create foam in the wetting fluid.
  • vent 28 is provided in a vertical section of the return conduit 26, at a location adjacent to or up to 24 inches downstream of the outlet 24.
  • the vent may also be located in a horizontal or angled section of the return conduit on the upper surface of the conduit.
  • Vent 28 may be take any number of embodiments, although it has been found that the easiest vent 28 to install and remove is one such as that shown in FIG. 4, namely a sleeve 30 having an outwardly directed vent stem 32.
  • Sleeve 30 is sized such that conduit 26 may be pushed onto each end of the sleeve 30 and clamped. Vent tubing 34 leading to and feeding into fountain tray 20 from vent stem 32 allows any liquid or foam which is vented to be recirculated in the circulation system.
  • Return conduit 26 will typically continue from the vent 28 downward to floor level.
  • a closed sump 36 such as the inverted U-shaped loop 37 in return conduit 26 is provided at this low point in the return conduit. Sump 36 promotes the exhaustion of air in the circulating system during initial start up, as will be described later in this section.
  • Venturi tube 38 is typically mounted at an elevation above the sump 36.
  • the suction provided by venturi tube 38 at return inlet 40 draws the wetting fluid from the sump 36 through the return conduit 26.
  • the venturi 38 then propels the wetting fluid through a filter means 41 such as a foam rubber filter to remove fibers, lint, dust and other debris collected in the wetting fluid.
  • the filter 41 may be submerged in a cooling reservoir 42, as shown in FIG. 1.
  • Reservoir 42 may be provided with refrigeration coils 44 and a refrigeration system to cool the wetting fluid.
  • Wetting fluid is withdrawn from the reservoir 42 by pump 45, which is typically a constant pressure pump such as a centrifugal pump.
  • the wetting fluid is flowed to flow divider 46, which directs a portion of the pump output to the venturi tube 38 and a portion of the pump output to feed line 60 leading to the inlet 22 of fountain pan 20.
  • a film of wetting fluid is collected by rollers 47 from fountain pan 20 and applied to press plate roller 48.
  • the present invention uses a venturi tube calibrated to provide a vacuum sufficient to draw the wetting fluid from its lowest point in the return line, without entraining air into the circulating system from the fountain pan.
  • a venturi tube using a single orifice can be so designed and calibrated, and is regarded as part of the present invention.
  • a venturi tube having two orifices allows a greater ability to calibrate the amount of vacuum to the particular layout of the return conduit.
  • venturi tube 38 has a fluid inlet 50 with a first aperture 52 mounted therein.
  • the second aperture may comprise the throat 54 of venturi tube 38.
  • the ratio of the inner diameter of the first orifice to the inner diamenter of the second orifice is about 0.5 to 1.25, allowing for a wide range of calibration of vaccum.
  • the first aperture has a inner diameter which is between .15 to .25 inches
  • the throat 54 of the venturi has an orifice size which is between .20 to .30 inches.
  • the preferred orifice sizes are respectively .20 inches for the first orifice and .25 inches for the throat orifice. It has been found that these orifices in combination provide a balanced amount of suction at the return inlet 40 so that the wetting fluid can be flowed through the system from the sump 36 without drawing air into the circulation system.
  • a wetting fluid specific gravity measuring apparatus and isopropanol metering system 56 such as the Balcontrol manufactured and sold by the Baldwin Technology Corporation, Stamford, Connecticut may be mounted at the flow divider 46.
  • the circulating system of the present invention has been found to eliminate problems of foaming found in the prior art systems, since the vent 28 allows entrained air to escape from the system before it is turbulently agitated in the the venturi, filter and pump.
  • the double orifice venturi tube provides a reduced suction in the return line over prior art venturi tubes having a single orifice designed for maximum suction; this reduced suction provides sufficient suction to draw the wetting fluid through the sump and return conduit, yet is not so powerful as to entrain air into the wetting fluid in the system.
  • the circulating system 10 has allowed fountain pan flow rates to be increased from the about 0.25 to 0.3 gallons per minute (GPM) flow rates achieved by the prior art systems to about 0.5 to 0.7 GPM, without the problems of foaming and flooding which would otherwise have occurred at such higher flow rates in the prior art devices.
  • GPM gallons per minute
  • the temperature increase from the inlet to the outlet of the fountain pan is decreased to about one half of the temperature increase of the prior art systems.
  • the sump 36 minimizes problems of foaming during start-up of the circulating system 10.
  • the sump 36 provides a pooling point for the wetting fluid and an additional pressure drop in the return conduit line during start-up so that the system can begin flowing wetting fluid to the fountain pan 20 without having an immediate intake of air to the circulation system 10 from the fountain pan outlet 24.

Landscapes

  • Rotary Presses (AREA)
  • Ink Jet (AREA)
EP88307801A 1988-01-12 1988-08-23 Zirkulationsvorrichtung und Verfahren um das Schäumen in der Anfeuchtvorrichtung einer Druckmaschine zu verhindern Withdrawn EP0325021A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US14299388A 1988-01-12 1988-01-12
US142993 1988-01-12

Publications (2)

Publication Number Publication Date
EP0325021A2 true EP0325021A2 (de) 1989-07-26
EP0325021A3 EP0325021A3 (de) 1990-03-21

Family

ID=22502109

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88307801A Withdrawn EP0325021A3 (de) 1988-01-12 1988-08-23 Zirkulationsvorrichtung und Verfahren um das Schäumen in der Anfeuchtvorrichtung einer Druckmaschine zu verhindern

Country Status (3)

Country Link
EP (1) EP0325021A3 (de)
JP (1) JPH01180341A (de)
CN (1) CN1038970A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4038021A1 (de) * 1990-11-29 1992-06-04 Edelmann Gmbh & Co Kg Einrichtung zum rueckfoerdern eines feuchtmediums aus einem feuchtwerk
WO1993019829A1 (de) * 1992-04-07 1993-10-14 Technotrans Gmbh Verfahren und vorrichtung zum recycling von verschmutztem prozesswasser
WO1996001741A1 (en) * 1994-07-08 1996-01-25 Pall Corporation Methods and apparatus for treating fountain solution
WO2002026498A1 (en) * 2000-09-25 2002-04-04 Varn Products Company, Inc. Dampening solution recirculator
EP1299240A1 (de) * 2000-07-07 2003-04-09 Baldwin Graphic Systems, Inc. Zirkulationssystem für druckmaschine

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8763617B2 (en) * 2009-06-24 2014-07-01 Saint-Gobain Abrasives, Inc. Material removal systems and methods utilizing foam
CN108705848B (zh) * 2018-04-28 2019-10-01 重庆川之舟印务设计有限公司 润版液净化装置
CN111114099B (zh) * 2020-02-06 2021-10-22 台州市雨免电子商务有限公司 一种纸板的印刷装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3352317A (en) * 1964-12-09 1967-11-14 Dahlgren Mfg Company Inc Dampening fluid cooling and circulating apparatus for lithographic offset press dampening device
EP0170160A2 (de) * 1984-08-01 1986-02-05 WEB ITALIA S.r.l. Anlage zum Zuführen von Feuchtmitteln für Offsetdruck

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3352317A (en) * 1964-12-09 1967-11-14 Dahlgren Mfg Company Inc Dampening fluid cooling and circulating apparatus for lithographic offset press dampening device
EP0170160A2 (de) * 1984-08-01 1986-02-05 WEB ITALIA S.r.l. Anlage zum Zuführen von Feuchtmitteln für Offsetdruck

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4038021A1 (de) * 1990-11-29 1992-06-04 Edelmann Gmbh & Co Kg Einrichtung zum rueckfoerdern eines feuchtmediums aus einem feuchtwerk
WO1993019829A1 (de) * 1992-04-07 1993-10-14 Technotrans Gmbh Verfahren und vorrichtung zum recycling von verschmutztem prozesswasser
WO1996001741A1 (en) * 1994-07-08 1996-01-25 Pall Corporation Methods and apparatus for treating fountain solution
US5622620A (en) * 1994-07-08 1997-04-22 Pall Corporation Apparatus for treating fountain solution
EP1299240A1 (de) * 2000-07-07 2003-04-09 Baldwin Graphic Systems, Inc. Zirkulationssystem für druckmaschine
EP1299240A4 (de) * 2000-07-07 2005-06-01 Baldwin Graphic System Inc Zirkulationssystem für druckmaschine
WO2002026498A1 (en) * 2000-09-25 2002-04-04 Varn Products Company, Inc. Dampening solution recirculator
US6651555B2 (en) 2000-09-25 2003-11-25 Day International, Inc. Dampening solution recirculator

Also Published As

Publication number Publication date
JPH01180341A (ja) 1989-07-18
CN1038970A (zh) 1990-01-24
EP0325021A3 (de) 1990-03-21

Similar Documents

Publication Publication Date Title
EP0325021A2 (de) Zirkulationsvorrichtung und Verfahren um das Schäumen in der Anfeuchtvorrichtung einer Druckmaschine zu verhindern
US5357307A (en) Apparatus for processing photosensitive material
US4994840A (en) Apparatus for processing photosensitive material
DE3147002A1 (de) Verarbeitungsgeraet fuer bildmaessig belichtete fotoempfindliche materialien
US3352317A (en) Dampening fluid cooling and circulating apparatus for lithographic offset press dampening device
JPH05220923A (ja) 湿し液供給システム
JP2906951B2 (ja) オフセット印刷機の湿し水供給装置
JPS5851155A (ja) 印刷機用のロ−ラ式インキ装置のインキを搬送するロ−ラを洗浄するための装置
EP1083046B1 (de) Vorrichtung mit zweifachem Luftvorhang zur Reduzierung des Eindringens von Feuchtmittel in das Farbwerk einer Offsetdruckmaschine
DE60124305T2 (de) Vorrichtung zur versorgung des stoffauflaufs einer papiermaschine oder deren äquivalent
US5524355A (en) Method and device for the transport of a liquid-gas mixture in a paper making machine
EP0254961B1 (de) Behandlungseinrichtung, insbesondere für im horizontalen Durchlauf zu behandelnde Leiterplatten
CN1205032C (zh) 印刷机循环系统
US5894795A (en) Apparatus and method for preventing condensation in machines processing a web of material
EP1362701A1 (de) Druckverfahren und Druckmachine zur Durchführung des Verfahrens
JPH0529878Y2 (de)
JPH0737367U (ja) ロール塗布装置
JPS6353946B2 (de)
JP3632602B2 (ja) 製版機の湿式現像装置
JP2001121067A (ja) 脱泡装置
CN1200496A (zh) 照相洗片机
DE10241251A1 (de) Verfahren zum Aufbringen eines Mediums auf eine bewegte Oberfläche
US5317359A (en) Apparatus for processing photosensitive material
JP3124261B2 (ja) オフセット印刷機の湿し水供給装置
DeJidas Alcohol-free printing

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE FR GB IT

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE FR GB IT

17P Request for examination filed

Effective date: 19900822

17Q First examination report despatched

Effective date: 19920320

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19930301