EP2119826A1 - Method and device for moistening a fibrous web - Google Patents

Abstract

The method comprises applying liquid and then steam on a fibrous web (2). The steam is applied as long as until 90% of the liquid are present on the surface of the web. After the application of the liquid, the steam is applied to a temporal interval of 1-100 ms and is applied with a spatial distance of 50-500 mm. The liquid is applied by saturated steam or wet steam, is heated before applying and is applied in the form of ice. The liquid from a liquid dispensing device (4) has a larger distance to the fibrous material web than the steam from a steam dispensing device (5). The method comprises applying liquid and then steam on a fibrous web (2). The steam is applied as long as until 90% of the liquid are present on the surface of the web. After the application of the liquid, the steam is applied to a temporal interval of 1-100 ms and is applied with a spatial distance of 50-500 mm. The liquid is applied by saturated steam or wet steam, is heated before applying and is applied in the form of ice. The liquid from a liquid dispensing device (4) has a larger distance to the fibrous material web than the steam from a steam dispensing device (5). The liquid mist and/or the steam suck off. The web temperature is 85-90[deg] C after the application of the steam. The liquid is applied as is required for a desired temperature increase through the subsequent application of the steam and as is required for remoistening the web. The application of the liquid uniformly distributes through the subsequent application of the steam. The liquid and/or the steam are applied over slit nozzles. The liquid is provided with additives and is applied in a quantity of 0.2-1.5 g/m 2>related to the surface of the fibrous web. The liquid is water, coating color, starch solution and coating chemicals. An independent claim is included for a device for moistening a fibrous web such as paper- or cardboard web.

Description

The invention relates to a method for moistening a fibrous web, in particular a paper or board web, in which first applying liquid and then steam to the fibrous web.

The invention further relates to a device for moistening a fibrous web, in particular a paper or board web, with a liquid dispensing device adjacent to a web running path and a steam dispensing device arranged along the web running path behind it.

Such a method and such a device are for example out EP 0 979 897 B1 known.

The invention will be described below with reference to the moistening of a paper web. But it is also in other fibrous webs, e.g. Cardboard or cardboard sheets, applicable in a corresponding manner.

When producing a paper web, moistening is necessary in many cases. For example, if you pass the paper web through a calender to satin it, you apply moisture to improve the calendering result. You want to do that achieve that the moisture application remains essentially on the surface of the paper web, because only there, the fibers are to be plasticized. The moisture, on the other hand, should preferably not penetrate into the interior of the paper web when passing through the nips in order to achieve a volume-saving calendering. So you want to achieve a moisture gradient and possibly also a temperature gradient.

There are several possibilities for moistening the paper web. One possibility is to apply the moisture in the form of steam. In this case, the vapor condenses on the surface of the web, which has the advantageous effect of increasing not only the moisture of the surface but also the temperature of the surface. This facilitates, for example, the subsequent calendering process. However, the amount of liquid applied thereto is highly dependent on the temperature of the web. If, for example, the paper web has passed through a calender with heat rollers, then the web temperature is at some point so high that a steam application gives it a very poor efficiency. Accordingly, a vapor deposition in or behind a calender is limited.

Another possibility is to apply the moisture in the form of a liquid which is atomized, for example in a nozzle moistener. However, there is no way to increase the temperature of the web significantly. In addition, it prepares In many cases difficulties to apply the moisture evenly in this way, since the liquid is always reflected in the form of individual drops on the surface of the paper web. In spite of fine drops, in many cases no homogeneous film is formed. This creates the risk of marks on the surface of the paper web. It takes a relatively long residence time of the liquid on the paper web before it can be introduced into a calender nip or other treatment device.

The invention has for its object to achieve the highest possible and low-interference moisture application.

This object is achieved in a method of the type mentioned in that applying the steam to the fibrous web, as long as previously applied liquid is still on the surface.

In this procedure, the first applied liquid serves as a nucleus or core for the condensation of the vapor applied thereafter, so that the condensation of the vapor is achieved largely independently of the temperature of the fibrous web. The condensation heats the already applied liquid. As a result, the viscosity of this liquid decreases and the surface tension is reduced, so that the applied liquid can now easily form a uniform liquid film. For this reason, it is possible to moisten the fibrous web also shortly before a nip of a calender or other processing device, without causing major disturbances on the surface. By the successive application of liquid and steam you have extensive possibilities to adjust the moisture and the temperature of the fibrous web independently. Neither of the two media is needed for the job of the other. In addition, the applied liquid acts as a heat conductor between the later applied steam and the fibrous web, so that the fibrous web can be further heated by the steam.

Preferably, the steam at a time interval in the range of 1 ms to 200 ms, in particular in the range of 1 ms to 100 ms, after the application of the liquid. This time interval is so small that it is ensured that in any case, a sufficient amount of liquid remains on the surface of the fibrous web. The liquid is sufficient to condense the steam to the desired extent.

Preferably, the vapor is applied at a spatial distance in the range from 20 mm to 2000 mm, in particular from 30 mm to 1500 mm and preferably in the range from 50 mm to 500 mm behind the application of the liquid. In today's web speeds, the distance is chosen so that when applying the steam enough liquid is still present on the surface of the fibrous web to achieve the desired effect.

It is also advantageous if the steam is applied as long as at least 75%, in particular at least 90%, of the liquid is present on the surface of the fibrous web. In this case, well over half of the applied liquid is available to condense the vapor. The liquid is heated by the steam, as already mentioned. Due to the relatively large amount of liquid, the liquid droplets that have formed on the surface of the fibrous web can then combine to form a film.

Preferably, the liquid is applied by saturated steam or wet steam. For example, steam may be passed into a cooled or simply low temperature steam box. The liquid then already has an elevated temperature, which has a positive effect on the further moistening of the fibrous web.

Alternatively or additionally, one can heat liquid prior to application. For example, you can use hot water for the moistening of the fibrous web.

Alternatively, you can apply the liquid in the form of ice. For example, if water is used for humidification, which is predominantly the case, then the liquid can be applied in the form of small ice crystals that have been previously prepared. Such ice crystals become the state as a solid maintained only a relatively short time. They are converted back into a liquid very quickly by the subsequent vapor deposition. Due to the lower temperature compared to a liquid, the steam can then condense to an increased extent, so that more moisture can be introduced by steam application than otherwise.

Preferably, the liquid at a greater distance from the fibrous web is discharged from a liquid dispenser than steam from a steam dispenser. The distance between the liquid of the dispenser and the web running path is thus greater than the distance between the steam dispenser and the web running path. The distance between the liquid dispensing device depends essentially on the desired quality of the spray application. The efficiency of the vapor deposition is the better, the closer the vapor dispensing device is arranged on the web running path.

Preferably, it sucks off liquid mist and / or steam. In this case, one avoids an exposure to the environment with liquid mist or steam. The moisture contained in the liquid mist or vapor can be reused.

It is preferable to apply only as much liquid as is required for a desired temperature increase by the subsequent vapor deposition. This is favorable if a temperature increase over the possible value in pure steam operation is required, but a moisture increase of the fibrous web should not be possible or should be as little as possible. The liquid is then used almost exclusively to serve as the condensation nucleus or germ for the vapor, so that as much vapor as possible can condense on the web, which leads to a corresponding increase in temperature.

Preferably, the web temperature after the vapor deposition is in the range of 80 to 100 ° C, in particular in the range of 85 to 90 ° C. Without a previous liquid application, such high temperatures can not be realized by a pure steam application. But if you apply liquid before and then let the steam condense, then you can enter a sufficient amount of heat in the web.

In an alternative embodiment, one bears as much liquid as is necessary for rewetting the web, and even out the liquid application by the subsequent vapor deposition. This can be used, for example, to avoid markings or streaks. In addition, the steam optionally serves to increase the rate of penetration by heating the web.

Preferably, the liquid and / or the vapor is applied via slot nozzles. With a slot nozzle, a distance of less than 25 mm to the surface of the web can be achieved for liquid application. The distance can then just as big as when steaming, which is very advantageous when using a common housing.

It is preferable to apply a liquid provided with additives. Such additives can, for example, support the penetration behavior, for example by reducing the surface tension of the liquid, or by performing a coating or assisting to homogenize the liquid application or to reduce disruptive deposits.

Preferably, the liquid used is water, at least one coating color, at least one starch solution, at least one coating chemical, polyacrylic acid and its salts with alkali metal ions, alkaline earth metal ions, polyvinyl alcohol, polyethylene glycol, polypropylene glycols, polysulfonic acids and / or long-chain organic ethers.

Preferably, the liquid is applied in an amount in the range from 0.1 to 8 g / m ² , in particular in the range from 0.2 to 1.5 g / m ^2, based on the area of the fibrous web.

1. a) Der Abstand liegt im Bereich von 20 mm bis 2000 mm , insbesondere im Bereich von 30 mm bis 1500 mm und bevorzugt im Bereich von 50 mm bis 500 mm,
2. b) bei Betriebsgeschwindigkeit benötigt die Faserstoffbahn eine Zeit im Bereich von 1 ms bis 200 ms, insbesondere von 1 ms bis 100 ms vom Ausgang der Flüssigkeitsausgabeeinrichtung bis zum Eingang der Dampfausgabeeinrichtung,
3. c) am Eingang der Dampfausgabeeinrichtung befindet sich noch mindestens 75 %, insbesondere mindestens 90 %, der in der Flüssigkeitsausgabeeinrichtung aufgetragenen Flüssigkeit noch auf der Oberfläche der Faserstoffbahn.

The object is achieved in a device of the type mentioned above in that a distance between an output of the liquid dispensing device and an input of the steam dispenser is selected so that at least one of the following conditions is met:

1. a) the distance is in the range from 20 mm to 2000 mm, in particular in the range from 30 mm to 1500 mm and preferably in the range from 50 mm to 500 mm,
2. b) at operating speed, the fibrous web requires a time in the range of 1 ms to 200 ms, in particular from 1 ms to 100 ms from the output of the liquid dispensing device to the input of the steam dispenser,
3. c) at the entrance of the steam dispensing device is still at least 75%, in particular at least 90%, of the liquid applied in the liquid dispensing device still on the surface of the fibrous web.

As mentioned above, it is ensured in this way that, when steam is applied, there is still a sufficient amount of liquid on the surface of the fibrous web. The liquid then has two tasks. On the one hand, it serves as a nucleus or condensation nucleus for the condensation of the vapor. On the other hand, it serves as a heat conductor to transfer the heat from the steam to the surface of the fibrous web. Conversely, the vapor has the beneficial effect of reducing the viscosity and surface tension of the liquid so that it is easier to form a uniform film of liquid on the surface of the fibrous web. With a uniform film of liquid on the surface you can then so moistened fibrous web through a nip in lead a calender or other treatment device without having a greater risk of damage to the fibrous web.

The liquid dispensing device and the vapor dispensing device preferably have a common housing. This housing can also be formed by the fact that the two devices are firmly connected. By choosing a common housing, it is possible to spatially arrange the liquid dispensing and the steam output so close together that in any case it is ensured that a sufficient amount of liquid is still present on the surface of the fibrous web to effect the condensation of the steam.

The liquid dispensing device preferably has a vapor inlet connection. It is then possible to feed the liquid dispenser and the vapor dispenser from the same source, namely a vapor source. Such a steam source is available anyway in many paper or board mills. The liquid can then be produced by cooling the liquid dispenser or otherwise maintaining it at a sufficiently low temperature. The liquid is then discharged in the form of saturated or wet steam, which has the advantage that the liquid itself can already be used to heat the fibrous web. Advantageously, the liquid dispensing device has a hot water connection. It is thus possible to supply the liquid dispensing device with already heated or heated liquid, which is then dispensed onto the fibrous web at a correspondingly high temperature.

Alternatively, the liquid dispenser may also be connected to an ice maker. An ice maker turns liquid into ice, preferably in the form of small ice crystals. When these ice crystals are discharged onto the surface of the fibrous web and then steam is applied, the ice crystals are particularly capable of causing condensation of the vapor. Although the ice crystals are melted. But this is desirable because you want to ultimately achieve a humidification of the fibrous web. Here you can apply a large amount of steam, which allows a particularly fine control.

Advantageously, the vapor dispensing device has a distance from the web travel path which is smaller than the distance of the liquid dispensing device to the web travel path. One can then choose the distance between the web running path and the liquid dispensing device on the one hand and the web running path and the steam dispenser on the other hand independently. With a small distance between the web running path and the steam dispenser, the efficiency of the steam dispenser is particularly good. A bigger one Spacing in the liquid dispenser makes it possible to achieve a good efficiency in the formation of a spray.

Preferably, a suction device is provided. The suction device is able to suck vapor or liquid mist, which is not absorbed by the fibrous web, and thus transported away. The environment is therefore not adversely affected.

The liquid dispensing device and / or the vapor dispensing device preferably has a slot nozzle arrangement. With a slot nozzle arrangement, one can achieve a relatively small distance between the dispenser and the web, which is particularly advantageous if one wants to make liquid application and vapor deposition from a common housing out. In this case, the slot nozzle is particularly advantageous for the liquid application.

Fig. 1

eine schematische Darstellung zur Erläuterung der Befeuchtung einer Faserstoffbahn,

Fig. 2

eine schematische Darstellung einer Vorrich- tung,

Fig. 3

eine Einbauposition einer Befeuchtungsvor- richtung im Bereich einer Walze,

Fig. 4

eine Einbauposition einer Vorrichtung im Be- reich einer freien Bahn,

Fig. 5

eine Einbauposition bei einer Befeuchtung von oben und

Fig. 6

eine schematische Darstellung einer Vorrich- tung mit Schlitzdüsen.

The invention will be described below with reference to preferred embodiments in conjunction with a drawing. Herein show:

Fig. 1

a schematic representation for explaining the humidification of a fibrous web,

Fig. 2

a schematic representation of a Vorrich- device,

Fig. 3

an installation position of a moistening device in the region of a roller,

Fig. 4

an installation position of a device in the area of a free path,

Fig. 5

an installation position with a humidification from above and

Fig. 6

a schematic representation of a device with slot nozzles.

Fig. 1 shows a device 1 for wetting a paper web 2. The paper web 2 is used here as an example of a fibrous web. Instead of the paper web 2, of course, a cardboard or board web can be moistened.

The paper web 2 is moved in a running direction 3 shown by an arrow on the device 1 along. Where the paper web 2 is located, a web running path is assumed.

The device 1 has in the running direction 3, first a liquid dispensing device 4 and then a steam dispenser 5.

The liquid dispensing device 4 dispenses liquid in the form of spray jets 6 in the direction of the paper web 2, so that a liquid film 7 is formed. The liquid film 7 must be in the area of the liquid dispensing device 4 not yet connected. He may also be there in the form of individual droplets. As soon as the liquid has arrived on the surface of the paper web 2, it begins to penetrate into the interior of the paper web 2. However, this requires a certain amount of time.

The paper web 2 runs during this time past the steam dispensing device 5, the steam jets 8 in the direction of the paper web 2 outputs. The steam transported by the steam jets 8 comes in contact with the liquid film 7, which has a lower temperature than the steam jets 8. Accordingly, the vapor condenses here and forms a further film referred to here as "steam film" 9, which, however, mixes with the liquid film 7. This approach has the advantage of being able to produce a sufficiently low temperature at the surface of the paper web 2 to cause the steam to condense. Accordingly, the heat energy contained in the steam can be almost completely used to heat the paper web 2 at the surface. The steam is thus applied with a relatively high efficiency.

The liquid film 7 is heated by the steam. As a result, the surface tension and the viscosity of the liquid forming the liquid film 7 are reduced, so that the droplets possibly formed during the liquid application can combine to form a uniform layer. By the increased Temperature, the liquid can then penetrate more easily into the surface of the paper web, so that the moistening and heating of the paper web 2 is favored.

Due to the separate application of liquid and steam, these two media can be set independently. If the liquid dispensing device 4 and the vapor dispenser 5 are subdivided into zones perpendicular to the direction of travel 3 of the paper web, which can be controlled independently, it is possible to be able to profile the moisture across the width of the paper web. Since it is possible to set the vapor deposition and the liquid application largely independently of each other, the profiling is possible both in terms of temperature and humidity. By zonal regulation of the amount of liquid and vapor, it is possible, for example, to apply liquid to profiles that are too dry at points in the air and steam to wet points when the steam is used in a subsequent process, e.g. passing through a nip of a calender causes greater drying. This allows targeted and energy-saving moisture profiling.

Due to the separate application of steam and liquid, moisture levels required for rewetting can be specifically adjusted.

The liquid should as far as possible to the steam order, so at least 75%, better yet at least 90%, present on the surface of the paper web 2. It should therefore only have penetrated into the paper web 2 to a small extent. In order to achieve this, the liquid dispensing device 4 and the steam dispensing device are arranged as close as possible to each other, advantageously even in a common housing. The spatial distance between the end of the liquid application and the start of the vapor deposition should be in the range of 20 mm to 2000 mm, in particular between 50 mm and 1500 mm and particularly preferably between 30 mm and 500 mm. The time interval of the job to a moving paper web 2 should be in the range of 1 ms to 200 ms, preferably between 1 ms and 100 ms.

If an increase in humidity is not required, then only enough liquid is applied to achieve the desired increase in temperature due to the vapor deposition. The web temperature is heated after the device 1 to temperatures in the range of 70 to 100 ° C, preferably at temperatures in the range of 80 to 90 ° C.

Fig. 2 shows schematically how to realize such a device. The device 1 is in this case arranged in front of a nip 10, which is formed between two rollers 11, 12. The liquid dispensing device 4 has a steam connection 13 and a hot water connection 14 and can be cooled in a manner not shown in detail in order to convert the introduced steam into wet or saturated steam. The liquid dispensing device 4 may also simply be designed as a nozzle moistener, in which water can be atomized by air or in some other way into fine droplets. The steam dispenser 5 has a steam connection 15. Incidentally, the same elements as in Fig. 1 provided with the same reference numerals.

The device 1 is arranged so close to the nip 10 that pass at production speed less than 0.2 s, preferably in the range of 0.2 to 0.02 s before the paper web 2 after passing by the device 1 through the nip 10 is running. In this way it is ensured that the desired moisture and temperature conditioning takes place only in the outer layers of the paper web 2.

Fig. 3 shows an embodiment in which the device 1 is arranged in the region of a deflection roller 16. Same elements as in the Fig. 1 and 2 are provided with the same reference numerals. It can be seen that a distance a between the liquid dispensing device 4 and the paper web 2, which rests on the surface of the guide roller 16, is greater than a portion b between the vapor dispenser 5 and the paper web 2. The distance a is preferably in the range of 15 to 200 mm, in particular from 100 to 120 mm. The distance b is in the range of 10 to 100 mm, in particular in the range of 15 to 25 mm. The distance a depends mainly on the desired quality of the spray application.

If one uses slot nozzles for the liquid application, then one can use the same distance a between the liquid dispenser 4 and the paper web 2 as between the steam dispenser 5 and the paper web 2. This distance is then preferably in the range of 15 to 20 mm.

It can be seen that the liquid dispensing device 4 and the vapor dispenser 5 have a common housing. At the entrance of the liquid dispensing device 4, a bulkhead 17 is still arranged.

In the web running direction 3 behind the steam dispenser 5, a hot air outlet 18 or another possibility for heating the paper web 2 can additionally be provided. Subsequently, if necessary, still a solid application 19 may be provided.

After the steam dispensing device 5, a suction device 20 can also be arranged. The suction device 20 may also, as indicated by arrows 21, unfold their effect in the region of the liquid dispensing device 4, so that there spray mist, which is not absorbed by the paper web 2, is sucked out.

Fig. 4 shows a similar embodiment, in which the only difference is that the device 1 is arranged in the region of a free web tension.

Accordingly, the liquid dispenser 4 is not curved.

Fig. 5 shows an embodiment in which the device 1 is arranged above the paper web 2 at least in the region of the liquid application. In this case, the paper web 2 facing side of the steam dispenser 5 is curved, so that there is a substantially uniform Spampfungsspalt.

In the arrangement of the device 1 in the direction of gravity above the paper web 2, the liquid can also be applied in the form of solid, ie in the form of ice crystals. For this purpose, the liquid dispensing device 4 is then connected to an ice generating device, not shown, which continuously produces ice crystals. The ice crystals reduce the temperature of the surface of the paper web 2 to a particular extent, so that subsequently the steam transported up with the steam jets 8 can condense particularly well.

Fig. 6 schematically shows the formation of nozzles of the device 1. Provided in the liquid dispensing device 4 first slot nozzles 22 and in the vapor dispensing device 5 second slot nozzles 23. Here is a distance t1 between the last in web direction 3 slot nozzle 22 for liquid and the first slot in the direction of web 3 23 for steam chosen to be in the range of 20 mm to 2000 mm, especially in the range of 30 mm to 500 mm and especially preferably in the range of 50 to 500 mm. Accordingly, the paper web 2 requires a time in the range of 1 ms to 200 ms, in particular from 1 ms to 100 ms, to get from the last slot 22 to the first slot 23.

The liquid used is preferably water, which may also be provided with additives in order to support the penetration behavior. The amount of liquid is preferably in the range of 0.1 to 8 g / m ² , preferably 0.5 to 2.5 g / m ² . In this case, one uses an amount of liquid from 2 to 2000 1 / h, preferably between 5 and 300 1 / h per meter width of the paper web. 2

The liquid is preferably atomized in two-substance nozzles by means of a gas, ie air or steam. Preferred pressures for the sputtering gas are in the range of 5 kPa to 300 kPa, preferably in the range of 10 kPa to 100 kPa. The amount of atomizing gas may be in the range of 100 to 2000 m ³ / h, preferably in the range of 150 m ³ / h and 400 m ³ / h per meter of web width.

The steam for vapor deposition should preferably have a temperature in the range of 115 to 135 ° C when entering the device 1. The steam should have a vapor pressure of 1.2 to 2.0 bar absolute, preferably in the range of 1.2 to 1.5 bar absolute. The steam is used in an amount of 0.2 to 5 g / m ² , preferably in the range of 0.5 to 2.5 g / m ² .

For profiling, the liquid dispenser 4 and the vapor dispenser 5 may be constructed zonal, each zone being separately controllable. The zone width for the liquid application is preferably in the range of 15 mm to 100 mm. A zone width of 20 mm or less is preferred. The zone width for the vapor deposition is in the range of 50 to 300 mm, preferably in the range of 50 mm to 100 mm.

The device 1 is preferably used in a calender. In this case, the liquid application should begin in a range of 0.02 s to 0.20 s in front of the nip 10, preferably in a range of 0.029 s to 0.14 s in front of the nip 10.

Claims (24)

Process for moistening a fibrous web, in particular a paper or board web, in which first liquid and then steam is applied to the fibrous web, characterized in that the steam is applied to the fibrous web as long as previously applied liquid is still on the surface. A method according to claim 1, characterized in that applying the steam at a time interval in the range of 1 ms to 200 ms, in particular in the range of 1 ms to 100 ms, after the application of the liquid. A method according to claim 1 or 2, characterized in that the steam with a spatial Distance in the range of 20 mm to 2000 mm, in particular in the range of 30 mm to 1500 mm and preferably in the range of 50 mm to 500 mm behind the application of the liquid applies. Method according to one of claims 1 to 3, characterized in that applying the steam as long as at least 75%, in particular 90% of the liquid on the surface of the fibrous web are present. Method according to one of claims 1 to 4, characterized in that applying liquid by saturated steam or wet steam. Method according to one of claims 1 to 5, characterized in that one heats liquid prior to application. Method according to one of claims 1 to 4, characterized in that applying liquid in the form of ice. Method according to one of claims 1 to 7, characterized in that the liquid with a greater distance from the fibrous web from a liquid dispensing device as a vapor from a steam dispenser. Method according to one of claims 1 to 8, characterized in that sucks liquid mist and / or steam. Method according to one of claims 1 to 9, characterized in that applying only as much liquid as is required for a desired increase in temperature by the subsequent vapor deposition. Method according to one of claims 1 to 10, characterized in that the web temperature after the vapor deposition in the range of 80 to 100 ° C, in particular in the range of 85 to 90 ° C. Method according to one of claims 1 to 9, characterized in that applying as much liquid as is required for re-wetting of the web, and evened the liquid application by the subsequent vapor deposition. Method according to one of claims 1 to 12, characterized in that applying the liquid and / or the vapor via slot nozzles. Method according to one of claims 1 to 13, characterized in that applying a liquid provided with additives. Method according to one of claims 1 to 14, characterized in that as the liquid water, at least one coating color, at least one starch solution, at least one coating chemical, polyacrylic acid and its salts with alkali metal ions, alkaline earth metal ions, polyvinyl alcohol, polyethylene glycol, polypropylene glycols, polysulfonic acids and / or long-chain organic ether used. Method according to one of claims 1 to 15, characterized in that the liquid in an amount in the range of 0.1 to 8 g / m ² , in particular in the range of 0.2 to 1.5 g / m ² based on the Apply surface of the fibrous web. Device for moistening a fibrous web, in particular a paper or board web, with a liquid dispensing device adjacent to a web running path and a steam dispenser arranged behind the web path, characterized in that a distance (t1) between an exit of the liquid dispenser (4) and an input of the steam dispenser (5) is chosen so that at least one of the following conditions is met: a) The distance (t1) is in the range of 20 mm to 2000 mm, in particular in the range of 30 mm to 1500 mm and preferably in the range of 50 mm to 500 mm. b) At operating speed, the fibrous web (2) requires a time in the range of 1 ms to 200 ms, in particular in the range of 1 ms to 100 ms from the output of the liquid dispenser (4) to the input of the steam dispenser (5), c) at the entrance of the steam dispenser (5) is still at least 75%, in particular at least 90% of the liquid dispensed in the liquid dispensing device (6) still on the surface of the fibrous web (2). Apparatus according to claim 17, characterized in that the liquid dispensing device (4) and the steam dispenser (5) have a common housing. Apparatus according to claim 17 or 18, characterized in that the liquid dispensing device (4) has a steam inlet connection (13). Device according to one of claims 17 to 19, characterized in that the liquid dispensing device (4) has a hot water connection (14). Apparatus according to claim 17 or 18, characterized in that the liquid dispensing device (4) connected to an ice maker. Device according to one of claims 17 to 21, characterized in that the steam dispensing device (5) has a distance b to the web running path, which is smaller than the distance a of the liquid dispensing device (4) to the web running path. Device according to one of claims 17 to 22, characterized in that a suction device (20) is provided. Device according to one of claims 17 to 23, characterized in that the liquid dispensing device (4) and / or the steam dispenser (5) has a slot nozzle arrangement.

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