EP1285754A2 - Device for rehumidifying a web - Google Patents

Abstract

The apparatus comprises an applicator roller (18) for applying remoistening agent to printed and partly dried product web (1), and heating element (22) for increasing the temperature of the agent so as to remove the contaminants by vaporization. <??>Independent claims are included for the following: <??>(1) arrangement of dryer, cooling device and remoistening apparatus; <??>(2) web-fed rotary printing press; and <??>(3) method for remoistening product web.

Description

The present invention relates to a device for rewetting a Goods web, in particular a paper web in a web-fed rotary printing press, according to the preamble of claim 1.

When printing on a web, for example a paper web, the web is unwound from a supply roll, passed through one or more printing units, the one Apply one or more colors to the web on one or both sides, and then for drying the material web by a dryer, for example a hot air dryer guided. The web is heated above a temperature level in the hot air dryer, in which the solvent contained in the printing ink used evaporates and can be discharged through an exhaust device of the dryer. At the same time however, a certain moisture content is also withdrawn from the web, which is negative affects the quality of the printed product to be produced. The web will then a cooling device, for example one or more cooling rolls Comprehensive cooling roll stand supplied, the web by heat transfer cooled on the cooling rollers and thereby the printing ink is cured.

To compensate for the removal of moisture in the dryer, it is known to the web by a suitable device, which is arranged after the dryer, the web supply the required moisture again. The one coming out of the dryer However, the web tears a certain layer of air with it, in the solvent and Oil vapors can be included, these vapors tend to be on the surface for example an application roller of a rewetting device or on the To precipitate the surface of a chill roll. This can cause it to continue Operation of the printing press to build up the condensed solvent or condensed oil vapors on the respective surfaces of the rollers and to one Lubricate the condensate on the printed paper web.

DE 44 05 332 A1 describes a rewetting system, in particular for Web offset machines with heat set drying, known, in which a web coming from a furnace is fed to a plurality of cooling rollers. To solve the Problem of building a solvent-color mixture on the cooling rollers provided the web first a number of air knives, then one Remoistening chamber with a number of water atomizing nozzles and then an additional spray nozzle system. The air knife with across the web width Distributed compressed air nozzles scrape the solvent off the web, which is then channeled can be suctioned off and fed back into the dryer again. In the The rewetting chamber is the one created by the water atomizing nozzles Droplets are partially evaporated by the warmth of the hot web, so that a moist mist in the chamber forms from the dried web is recorded. The additional spray nozzle system is immediately before the first one Cooling roller and the second cooling roller attached. The positioning of the Spray nozzle system immediately before the web enters the chill rolls causes the sprayed-on dampening solution is forcibly wrapped around the web Cooling rollers is incorporated.

The combination of three devices for applying a dampening solution to the web while preventing the build-up of a solvent-color mixture on the Chill rolls thus have a complex structure, with the problem that the Solvent vapors swept along by the web on the many components of the three mentioned devices, especially on the inside of the chamber walls condense and return to the running web from there.

From US 4,637,341 is also a device for applying silicone oil-water emulsion known on a paper web, the emulsion using a heat exchanger can be brought to a desired temperature level which is higher or may be lower than the ambient temperature. This device also exists the problem of contamination of the silicone oil-water emulsion with impurities, z. B. paint residues, which can get into the storage tank via the roller surface.

It is an object of the present invention to provide an apparatus and a method create which overcome the disadvantages of the prior art.

Furthermore, it is an object of the present invention to provide a device create, which has a simple, little space-consuming structure, and with is easy to clean and maintain, requiring little time and costs.

Another or alternative object of the present invention is to provide a To create device that pollutes little or substantially not.

Another or alternative object of the present invention is to provide a To create a process in which contamination of an application roller is reduced or substantially prevented.

These objects are achieved by the features of claims 1 and Claim 13 solved. Further features of the invention are in the dependent Subclaims included.

A device for rewetting a web, in particular a paper web in a web-fed rotary printing press, the device comprising means for applying a Remoistening agent on the printed and at least partially dried Has web, is characterized in that means for heating the Remoisteners are provided.

According to the invention, means for heating the rewetting agent used, whereby the temperature of the rewetting agent can be increased in this way can that condensed solvent, oil vapors or the like, which in the Rewetting agents have come through evaporation of the Remoisteners can be separated. This is advantageous avoided contamination of the rewetting agent with the condensed Solvent or oil vapors through the means for applying the Re-moistening agent get back on the web and thereby the quality the products to be produced, e.g. B. the printed products, is reduced. The one from the Remoistener driven impurities can preferably be from aspirated and z. B. fed to and from a dryer be burned with energy recovery and pollutant reduction.

Another embodiment of the invention can provide that the device at least one application roller, in particular an application roller with a metallic and / or polished surface for applying the rewetting agent to the Goods web and / or at least one storage container for receiving the Remoistening agent, in particular a tub, comprises.

Advantageously, the use of an application roller, which the Re-moistening or scooping out of a tub and onto the web emits the application of the in a simple manner and with few components Remoistener reached.

Furthermore, it can preferably be provided that the means for heating the Remoistening agent in or on the reservoir, e.g. B. the tub to be arranged and in this way by heating the rewetting agent Separating contaminants from the rewetting agent by evaporation, especially remove from the tub.

It is also possible to provide the tub with a lid, which has an opening for Reaching through the application roller and which continues with a Suction device is connected, which is the evaporated solvent or Oil vapors, which are in the enclosed space of the lid Vacuum the tub.

In addition, it is also advantageously possible to separate the application roller, z. B. driven by a motor. However, it can also be provided that Drive the application roller solely by the friction mediated by the web. The Using a separate drive for the applicator roller allows in advantageous Way to rotate the applicator roller at the desired speed, and thereby optionally a desired slip between the surface of the Generate application roller and the transported web.

The application roller can also expediently be equipped with a counter-pressure roller interact, which is arranged on the other side of the web.

In a further embodiment of the invention, the means for applying the Remoistening agent, e.g. B. the applicator roller, at the same time as a means of heating of the rewetting agent.

So it is z. B. possible that the applicator roller from a heated fluid, for. B. water is flowed through, which by heat transfer the applicator roller, especially its Surface heated, the heat re-wetting agent in turn is heated in such a way that the mediated by the condensed solvent and oil vapors Contamination from the evaporation process Remoisteners can be driven out.

In a further embodiment of the invention it can be provided that the means for Heating the rewetting agent preferably an electrically operated one Heating coil and / or a heat exchanger, e.g. B. one of a heated fluid flow through heat exchanger.

Here, for. B. can be provided in an advantageous manner, the heating coil and / or Arrange heat exchanger within the tub, from which the application roller or a Bucket roller scoops the rewetting agent in a simple manner and to cost-effectively heat the rewetting agent.

In addition, it is also possible to interpose a device according to the invention a dryer and a cooling device, in particular between a hot air dryer and a cooling roll stand, or directly in front of the cooling device, in particular directly in front a first cooling roller of the cooling device, or within the cooling device, to be arranged in particular directly in front of the first cooling roller of the cooling device.

Through each of these preferred arrangements of the device according to the invention, the Precipitation and build-up of solvent, oil vapors or the like on components the cooling device, in particular on chill rolls of a chill roll stand, prevented become.

It is Z. B. possible by the upstream of the first cooling roller according to the invention Device to realize a trap for the vapors mentioned, so that time and costs complex cleaning processes are eliminated and at additional costs causing cleaning devices can be dispensed with.

The application roller can preferably be arranged directly in front of the first cooling roller Apply the rewetting agent to the side of the web with which the Material web wraps around the first cooling roller. This is advantageous ensures that condensation of vapors on the first chill roll is prevented is and at the same time the desired rewetting of the web is achieved.

It is also possible to have another device for rewetting the web to arrange the side of the web which is facing away from the first cooling roller. The further device can, for. B. arranged directly opposite a first device or be arranged between the first and a second cooling roller. Through the further device according to the invention is further ensured that a Prevents build-up of contaminants on the surface of the second cooling roller becomes.

In a further embodiment of the device according to the invention, it can be provided that that the first cooling roller serves as an application roller.

This has the advantage that saving on a separate applicator roller costs and materials can be dispensed with. The cooling roller can do that Remoistening agent directly or via a scoop roller from a storage container, e.g. B. a tub.

It is also possible that the rewetting agent is water and / or silicone contains, in particular a separate quantity control of the water content and / or Silicone portion can be provided.

The separate volume control enables the operator to operate the water and adjust the silicone content at any time in such a way that optimal wetting of the agent for applying the rewetting agent, for example an application roller, and optimal rewetting of the web is achieved. The separate Volume control can be effected by the user by hand, but it is also conceivable that an automatic control device the separate quantity control takes over.

A further embodiment of the invention can provide an external heating device, which comprises a storage container and a heating element and which via lines and at least one pump is connected to a tub. So it is more advantageous Way also possible, the space-taking heating device, in particular also their Wiring, spatially distant from the application roller or z. B. also from one Arrange chill roll stand and thereby improved access for an operator to enable the machine.

• Erhöhen der Temperatur des Wiederbefeuchtungsmittels (22, 122) derart, dass Verunreinigungen durch Verdampfen von dem Wiederbefeuchtungsmittel (22, 122) getrennt werden aus.

A method according to the invention for rewetting a material web, in particular a paper web in a web-fed rotary printing press, wherein at least one application roller (18, 6) is provided for applying a rewetting agent (24) to the printed and at least partially dried material web (1)

• Increasing the temperature of the rewetting agent (22, 122) such that contaminants are evaporated from the rewetting agent (22, 122).

Furthermore, a web-fed rotary printing press, in particular one Roll rotary offset printing machine can be provided, which is characterized as above characterized described device according to the invention.

The invention is more preferred below with reference to the drawings on hand Embodiments described.

Figur 1

eine schematische Seitenansicht einer erfindungsgemäßen Vorrichtung in einem einem Trockner nachgeordneten Kühlwalzenstand;

Figur 2

eine schematische Seitenansicht einer erfindungsgemäßen Vorrichtung mit einer Absaugeinrichtung;

Figur 3

eine schematische Seitenansicht einer erfindungsgemäßen Vorrichtung mit einer zusätzlichen Schöpfwalze;

Figur 4

eine schematische Seitenansicht einer erfindungsgemäßen Vorrichtung, wobei eine Auftragswalze zum Erwärmen des Wiederbefeuchtungsmittels eingesetzt wird;

Figur 5

eine schematische Seitenansicht einer erfindungsgemäßen Vorrichtung mit einer separaten Mengenregelung des Wasser- und Silikonanteils;

Figur 6

eine schematische Seitenansicht einer erfindungsgemäßen Vorrichtung mit einer externen Heizeinrichtung.

Show in the drawings

Figure 1

is a schematic side view of a device according to the invention in a cooling roller stand downstream of a dryer;

Figure 2

a schematic side view of a device according to the invention with a suction device;

Figure 3

is a schematic side view of a device according to the invention with an additional scoop roller;

Figure 4

is a schematic side view of an apparatus according to the invention, wherein an application roller is used to heat the rewetting agent;

Figure 5

is a schematic side view of a device according to the invention with a separate amount control of the water and silicone content;

Figure 6

is a schematic side view of a device according to the invention with an external heating device.

Corresponding components are provided with the same reference symbols in the figures.

In Figure 1, a web 1, z. B. a paper web, shown which from a dryer 2 coming a cooling roll stand 4 is supplied, in which it along its path is guided around several cooling rollers 6, 8, 10. The web 1 leaves the dryer through an opening 12 and also enters the chill roll stand 4 through an opening 14 a, wherein it can also be provided that the two openings 12 and 14 one and represent the same opening, which in a partition between the dryer 2 and the downstream cooling roll stand is provided.

In front of the first cooling roller 6 of the cooling roller stand 4, a device 16 according to the invention for rewetting the web 1 is arranged, which comprises an application roller 18, a trough 20 and a heating element 22. In the tub 20 there is a certain amount of rewetting agent 24, which, for. B. can be composed of water and up to 30% silicone, and which is picked up by the surface of the application roller 18 and released to one side of the web 1.
The heating element 22, which, for. B. can be operated electrically, serves to heat the rewetting agent 24 in the tub 20, so that residues of condensed solvent, oil vapors or the like, which enter the rewetting agent via the application roller 18, can be removed from the rewetting agent 24 by increasing the temperature and evaporation ,

FIG. 2 also shows a device for rewetting the web 1, the device in addition to the applicator roller 18, the tub 20 and the heating element 22 also has a cover 26 through which the application roller 18 at least partially protrudes and is in contact with the rewetting agent 24. The Lid 26, which can also be an integral part of the tub 20, is above a Line 28 with a pump element 30 in connection, which continues via a Line 32 communicates with a container 34. The one from the Remoistener 24 evaporated solvent and oil residues are in the captured by the lid 26 and the tub 20 enclosed space and over the Lines 28 and 32 are brought into a container 34 by means of the pump element 30, where they z. B. can be subjected to a recovery process by condensation. However, it is also possible to direct the vapors to the dryer 2 via the line 32 feed and there the combustion process with energy recovery and To provide pollutant reduction. The pump element 30 can also by a pump element located in the dryer 2 can be replaced.

FIG. 3 further shows an inventive device for rewetting 16, in which a first cooling roller 6 of a cooling roller stand serves as an application roller. The Remoistening agent 24 is scooped out of the tub 20 via a scoop roller 36 and transferred from the scoop roller 36 to the cooling roller 6 operating as an application roller, from where the rewetting agent film 38 reaches one side of the web 1.

A device 16 according to FIG. 3 can, however, also be configured such that the Re-moistened 24 directly from the cooling roller 6 from the tub 20 and is applied to one side of the web 1.

FIG. 4 shows a device 16 for rewetting a web 1, at which an applicator roller 18 has a hollow interior 40, which of a Heating medium, e.g. B. is flowed through a heated fluid. The fluid, e.g. B. water can are heated by a heating device 22 in a storage container 42 and over Lines 44 and 46 with the aid of a pump element 48 the hollow interior 40 of the Applicator roller 18 are supplied. Due to heat transfer, the jacket becomes Applicator roller 18 is heated and in turn due to heat transfer occurs Temperature increase of the rewetting agent 24 in the tub 20.

FIG. 5 shows a device 16 for rewetting a web 1, which compared to the device 16 shown in Figure 1, a device for separate Volume control of the water and / or silicone portion of the rewetting agent 24 having. There is a reservoir 50 for water and a reservoir 52 for Silicone provided, the water via lines 54 and 56 using a Pump element 58 and the silicone via lines 60 and 62 using a Pump element 64 from the respective reservoir 50 and 52 to the tub 20 is promoted. A control device 66, which with the pump elements 58 and 64 in Connection is established and which via a measuring sensor, not shown Monitored composition of the water-silicone mixture in the tub 20, controls the Supply of water and silicone through the pumping capacity of the respective pumps 58 and 64. The control device 66 can be actuated by the operator or automatically the composition of the water-silicone mixture of the rewetting agent 24 z. B. regulate to a predetermined value.

It is preferably also possible to mix the water and silicone outside the tub to produce and then feed it.

Fig. 6 shows a device 16 for remoistening the web 1, comparable to the 2, in this embodiment of the invention however, instead of the heating element 22 in the tub 20 (see FIG. 2) an external one Heating device 122 is provided. The heater 122 includes one Storage container 124, in which rewetting agent 24 is stored and from a heating element 22 can be brought to a desired temperature. about Lines 126 and 128 and by means of a pump 130 can be tempered Remoistening agent from heater 122 to tub 20 as needed be promoted. A fill level sensor (not shown) can be provided which detects and switches on the fill level of the rewetting agent 24 in the tub 20 a control device, also not shown, reports which via a control the pump 130 controls the refilling of the rewetting agent 24 into the tub 20 or also regulates.

LIST OF REFERENCE NUMBERS

1

web

2

dryer

4

Chill stand

6, 8, 10

chill rolls

12, 14

openings

16

Device for rewetting

18

applicator roll

20

tub

22

heating element

24

remoistening

26

cover

28

management

30

pumping element

32

management

34

container

36

scoop roller

38

Wiederbefeuchtungsmittelfilm

40

Interior of the application roller

42

reservoir

44, 46

cables

48

pumping element

50, 52

reservoir

54, 56

cables

58

pumping element

60, 62

cables

64

pumping element

66

control device

122

heater

124

reservoir

126

management

128

management

130

pump

Claims (13)

Device for rewetting a web, in particular a paper web in a web-fed rotary printing press, the device having at least one application roller (18, 6) for applying a rewetting agent (24) to the printed and at least partially dried web (1),
characterized in that means are provided which increase the temperature of the remoistening agent (22, 122) in such a way that contaminants are separated from the remoistening agent (22, 122) by evaporation. Device according to claim 1,
characterized in that the device has at least one application roller with a metallic and / or polished surface for applying the rewetting agent (24) to the web (1) and / or at least one storage container (20) for receiving the rewetting agent, in particular a trough (20 ). Device according to claim 2,
characterized in that the applicator roller (18, 6) is driven separately. Device according to one of the preceding claims,
characterized in that the means for applying the remoistening agent (18, 6), for example the applicator roller (18, 6), also serve as means for heating the remoistening agent. Device according to claim 4,
characterized in that a heated fluid, for example water, flows through the application roller (18, 6). Device according to one of claims 1 to 4,
characterized in that the means for heating the rewetting means (22, 122) comprise an electrically operated heating coil and / or a heat exchanger, for example a heat exchanger through which a heated fluid flows. Device according to one of the preceding claims,
characterized in that the device (16) between a dryer (2) and a cooling device (4), in particular between a hot air dryer (2) and a cooling roll stand (4), or directly in front of the cooling device (4), in particular directly in front of a first Cooling roller (6) of the cooling roller stand (4), or within the cooling device (4), in particular directly in front of the first cooling roller (6) of the cooling roller stand (4). Device according to claim 7,
characterized in that the application roller (18, 6) is arranged directly in front of the first cooling roller (6) and the rewetting agent (24) is applied to the side of the web (1) with which the web (1) carries the first cooling roller (6) wraps. Device according to one of claims 2 to 8, characterized in that the first cooling roller (6) serves as an application roller (18, 6). Device according to one of the preceding claims,
characterized in that the rewetting agent contains water and / or silicone, in particular a separate quantity control (66, 58, 64, 50, 52) of the water portion and / or the silicone portion being provided. Device according to one of claims 2 to 10, characterized in that the means for heating the rewetting agent (122) are connected to the trough (20) via at least one line (126, 128). Web-fed rotary printing machine, in particular web-fed rotary offset printing machine, characterized by
a device (16) according to one of the preceding claims. Method for remoistening a web, in particular a paper web in a web-fed rotary printing press, at least one application roller (18, 6) being provided for applying a rewetting agent (24) to the printed and at least partially dried web (1),
characterized by the process step:
Increasing the temperature of the rewetting agent (22, 122) such that contaminants are separated from the rewetting agent (22, 122) by evaporation.

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