EP1088594B1 - Method and device for spraying a moving fibrous web - Google Patents

Description

The invention relates to a method and a device for spraying a moving fibrous web, in particular paper or board web, by means of at least a nozzle, wherein the nozzle is a preferably adjustable volume flow the relevant spray medium is supplied.

Such a method according to the preamble of claim 1 and An apparatus according to the preamble of claim 14 is made EP 0 705 688.

In the production, finishing and processing of fibrous webs Spray systems are used to target specific web properties to influence. These properties may include, for example the moisture content, the surface moisture, the surface coating and / or the like. Alternatively or additionally is also a Vaccination with additives conceivable. For applications where using a Variable volume flow is sprayed (see, for example, the moisture cross-profiling with nozzle humidifiers in papermaking), are currently coming the following two control concepts are used:

1. Parallel connection of the valves (binary volume flow control)

In such a parallel connection of the valves with binary flow control be multiple valves with different Flow rate as a valve block connected in parallel. each Valve only knows the condition open or closed. By Open individual valves with different volumetric flow additively produce different total volume flows.

This control concept has the disadvantage that the addition can only generate a stepped volume flow characteristic. Another Disadvantage is the large number of individual valves per nozzle and thereby conditional large space requirement and high price of the valve block.

2. Row arrangement of the nozzles (Binary volume flow control)

In such a series arrangement, several nozzles with different flow rate when spraying in the web running direction arranged one behind the other. Each nozzle is from one Valve controlled, only the state opened or closed knows. Leave by combining individual open nozzles additively produce different total volume flows.

This control concept has the disadvantage that the addition can only generate a stepped volume flow characteristic. Another Disadvantage is the large number of individual valves and nozzles and thereby conditional high price of the total spray unit.

Proportional valves come with the current state of the art small volume flows hardly used because the control range too small and the clogging sensitivity is too high. In addition, these valves very expensive.

From EP 0 705 688 and DE 689 24 433 T2 is a pulsed humidification spray system it is known that feeding a dampening fluid to a roller of a Printing press is used.

The aim of the invention is a method according to claim 1 and an apparatus according to claim 14 of the beginning to create said type, in which the aforementioned disadvantages are eliminated.

With regard to the method, this object is achieved according to the invention solved that the Sprühmedium volume flow of the nozzle over at least a pulsation valve is supplied, wherein the volume flow of the spray medium occurring pulsations preferably attenuated or attenuated become. In this case, the volume flow supplied to the nozzle is preferably adjusted via the pulsation valve.

The pulsation valves are preferably used in paper and board machines, especially in nozzle moisteners, coating units, starch spray systems, Profiling systems etc. used. Basically, a Use for volume flow control of liquids in nozzles during spraying fiber-containing moving webs, especially in sprayers in paper and board machines, in particular in jet dampers, Coating units, starch testing equipment, profiling equipment etc. possible.

As a pulsation valve is preferably an anchor valve and in particular a plate anchor valve used.

Pulsating valves as such are already in the documents DE 41 396 71 C2 and DE 44 194 46 C2.

In a preferred practical embodiment, the volume flow the pulsation occurring by means of at least one of the spray medium the nozzle upstream pulsation damper and / or by the Use of a nozzle with a correspondingly large in the web running direction measured spray width and / or through the use of a flexible Supply line attenuated or attenuated to the nozzle.

Pulsation dampers or pulse dampers use the compressibility of Gases to compensate for pressure fluctuations. The arrangement of the supply line and the output line in one compared to the line cross section this allows much larger closed gas volume Infuse the liquid until both cross sections (inlet and Exit) into the liquid. The remaining gas volume is enclosed and compressed according to the applied pressure. The gas pre-charge pressure is adapted to the operating pressure. Rapid pressure fluctuations (pulsations) change this Volume of caged gas (predominantly air). The energy-transforming Compression and expansion of the gas cushion smoothes the incoming Pulsations.

When used in particular in combination with a pulsation valve flexible soft feed line to the nozzle, the circumstance is exploited, that the elasticity of such a flexible nozzle feed line is a damping Has effect. The flexible nozzle lead can, for example, by a polyethylene. Polyurethane or polyamide be formed. she may for example have a length, in particular greater than 3 m and preferably greater than 5 m. An appropriate arrangement will preferably in paper and board machines, in particular in nozzle moisteners, Coating units, starch spraying plants, profiling plants etc. used.

Advantageously, a nozzle is used whose in the web running direction measured spray width at least 30%, and preferably at least 50 % of the spray width measured in the web transverse direction.

In certain cases, it is advantageous if the nozzle is a flat jet nozzle is used. In this case, for example, an elliptical flat jet nozzle be used.

Such flat jet nozzles, in particular in combination with the used Pulsationsdämpfern and / or flexible nozzle feeders which provide sufficient attenuation of the pulsations. Flat jet nozzles have the property that all rays under approximately the same angle in the web running direction on the fibrous web incident. The efficiency of dampening depends on this angle from. This has the advantage that the optimum angle for a maximum Moisture efficiency can be adjusted.

In a preferred practical embodiment, the nozzle is a Flat fan nozzle used at an angle of attack to the fibrous web sprays against the web running direction, the angle of attack in particular less than about 80 ° and preferably less than about 70 ° can. Thus, the efficiency of the moisture is increased accordingly or a mists reduced. A corresponding flat jet nozzle can advantageously is used at web speeds greater than in particular 1200 m / min and preferably greater than 1500 m / min. A corresponding arrangement is preferably used in paper and board machines, especially in nozzle moisteners, coating units, starch spray systems, Profiling systems etc. used.

In certain cases, it may also be advantageous if a nozzle as a Full cone nozzle is used.

The volume flow supplied via such a pulsation valve advantageously becomes be set via a pulse width modulation. there the pulsation valve is preferably driven at a constant clock frequency.

The specified method is advantageously used in paper or board machines and in particular in nozzle moisteners, coating units, Stärkesprühanlagen, profiling and / or the like applied.

The device according to the invention is accordingly characterized that the spray medium volume flow of the nozzle via at least a pulsation valve is supplied, wherein preferably means provided are pulsations occurring in the volume flow of the spray medium to dampen or mitigate.

Advantageous embodiments of the device according to the invention are specified in the dependent claims.

• kontinuierliche Regelung eines mittleren Volumenstroms von 0 % bis 100 %
• auch für kleinere Volumenströme und Flüssigkeitsdrücke geeignet
• infolge des großen Regelbereichs nur ein Ventil und nur eine Düse pro Sprühposition in Maschinenquerrichtung erforderlich

As a result of the method according to the invention and the device according to the invention, in particular pulsation valves such as, for example, anchor valves and in particular plate anchor valves, ie valves with a plate anchor, can also be used in paper and board machines. In particular, a use in nozzle humidifiers, coating units, Stärkesprühanlagen, profiling and / or the like is possible. The respective pulsation valves can be provided in particular for volume flow control of the respective spray medium. Thus, in particular, the following advantages of such pulsation valves can also be used:

• continuous control of a medium volume flow from 0% to 100%
• Also suitable for smaller volume flows and liquid pressures
• due to the large control range only one valve and only one nozzle per spraying position in the cross machine direction required

Due to the formation of the invention is excluded that the transmitted pulsations generated by such valves on the spray liquid become.

• Pulsationen in der Sprühflüssigkeit, wie sie insbesondere durch Pulsationsventile erzeugt werden, werden gedämpft
• Sprühmengenschwankungen auf der bewegten Faserstoffbahn werden entsprechend verringert

The respective pulsation damper (or elastic supply lines) can be used in particular in lines for liquids or suspensions in paper and board machines. For example, at least one pulsation damper in the relevant line can be used between a nozzle and a valve of any design, preferably a pulsation valve. The pulsation dampers can be used, for example, in systems for spraying moving fibrous webs, in particular in spraying systems in paper and board machines, and in particular in nozzle moisteners, coating units, starch spray systems, profiling systems and / or the like. The advantages of these pulsation dampers include:

• Pulsations in the spray liquid, as generated in particular by pulsation valves, are damped
• Sprühmengenschwankungen on the moving fibrous web are reduced accordingly

Pulsation valves, in particular anchor valves and preferably plate anchor valves especially for use in paper and paper Cardboard machines with pulsation dampers and / or flexible supply lines be combined. Thus, in particular, a unit of a pulsation valve and a pulsation damper and / or an elastic nozzle feed line be formed.

Pulsation valves, in particular anchor valves and preferably plate anchor valves can except with pulsation dampers and / or flexible Supply lines also combined with the respective Flüssigkeitsssprühdüse become. Such combinations, for example, are applicable again in installations for spraying moving fibrous webs, in particular in sprayers in paper and board machines and in particular in nozzle moisteners, coating units, starch spray systems, profiling plants and / or the like. It can thus be a single unit from a pulsation valve, a pulsation damper and / or a flexible Feed line and a nozzle are formed.

An advantage of such a unit of pulsation damper and / or more flexible Supply line, valve and nozzle is that a pulsating valve, due to the pulsation damping, also for spraying moving Railways can be used.

Pulsation valves, in particular anchor valves and preferably plate anchor valves for spraying moving fibrous webs for use especially in spraying equipment for paper and board machines, especially in nozzle moisteners, coating units, starch spray systems, Profiling systems and / or the like, in particular can also be used in combination with nozzles whose spray width is large in the web running direction, in particular greater than 30 % of the spray width in the web transverse direction, in particular elliptical Flat jet nozzles or full cone nozzles are usable. It can thus in particular also a respective unit of a pulsating valve and a nozzle with a large spray width are formed.

Among the advantages of using such nozzles in context with pulsating valves, among other things, that due to the large spray width in Web running direction attenuated a pulsation in the flow in the spray pattern becomes. This is due to the fact that the moistening of a Point on the moving web through the large spray width over one longer period of time. This will cause volumetric flow fluctuations balanced during this period at the point.

Pulsating valves such as in particular anchor valves and preferably plate anchor valves can also be used in combination with at least one pulsation damper and / or a flexible supply line and in combination with Nozzles are used whose spray width is large in the web running direction and in particular greater than 30% and preferably greater than 50 % of the spray width in the web transverse direction, in particular elliptical Flat jet nozzles or full cone nozzles for spraying moving fibrous webs can be used. It is especially one again Use in spraying equipment in paper and board machines, especially in nozzle moisteners, coating units, starch spray systems, Profiling systems and / or the like, possible. A respective pulsating Valve can thus in particular also in combination with a Pulsation damper and a nozzle with a large spray width can be used.

Due to the large spray width of the nozzle in the web running direction and the use At least one damper will be moisture fluctuations largely eliminated by spraying on the moving web, thereby In particular, an insert for fast moving webs is possible.

In particular, there is also a method and a device for controlling the volume flow with at least one pulsation valve for liquid Media created, the volume flow at a nozzle or a nozzle group regulate and for spraying moving fibrous webs in particular can be used in spraying machines for paper and board machines in particular also a use in nozzle dampers, Coating units, starch spraying plants, profiling plants and / or the like is possible.

Pulsation valves in themselves generate a pulsating volume flow, the when spraying moving webs are transferred to the spray pattern can. The applied spray amount would thus in the direction of the Vary track according to the pulsation. The extent of the Variation of the spray rate on the following factors: Frequency of the Pulsation, web speed, spray width in web direction, number the nozzles in the web running direction and damping the pulsation. by virtue of The solution according to the invention are now undesirable volume flow fluctuations in fluid lines, for example, conditionally by natural vibrations of machine components such as in particular such Pulsation valves, steamed in paper and board machines.

With the use of one or more Pulsationsventile you get a continuous, i. continuous and non-cascaded volumetric flow characteristic over the entire control range. In contrast to the stand Thus, according to the technique, any volumetric flows can be set, which may be e.g. a more precise response function for moisture profiling with nozzle moisteners allowed.

Due to the damper system according to the invention is a pulationsarmes Spraying possible. This is done, for example, by reducing fluid fluctuations after the pulsation valve in particular at least 50%, in particular at least 80% and in particular at least 90% just before the nozzle reached. This will be pulsations in the spray liquid caused by vibrating machine parts such as a pump or a pulsating valve were created, damped, whereby the uniformity of the spray pattern in the web running direction is improved.

It is a uniform spraying of a moving fibrous web like in particular a paper web possible whose speed v greater as for example 500 m / min, in particular greater than 1000 m / min and preferably greater than 1500 m / min can be. With increasing web speed can also handle volumetric flow fluctuations with high Frequencies can be seen on the spray pattern.

With fewer valves per nozzle, especially with just one valve per nozzle, can be compared to the prior art, especially in sprayers for paper and board machines smaller dimensions for the Control unit can be achieved, which may allow the valve directly in to integrate the spray bar.

Due to the smaller number of valves compared to the prior art and / or nozzles, in particular with only one valve per nozzle or only a nozzle per spray position in the web transverse direction, and / or less expensive Valves can be used in particular in spraying systems in paper and board machines lower maintenance and cheaper sprayers getting produced.

As a spray medium, for example, liquids, especially water, Starch, vaccines, (paints and varnishes) conceivable.

The volume flows per nozzle and / or valve, for example, in a Range up to a maximum of 30 l / min, in particular up to a maximum of 0.70 l / min and preferably up to a maximum of 0.20 l / min.

The device according to the invention is also characterized by a relative high durability. For example, use is extensive Continuous operation with over 70% operating time, especially with over 90% Operating life with a life of at least 3 years, in particular at least 5 years imaginable.

The invention is particularly also at pressures of less than 20 bar, in particular less than 2 bar and preferably less than 1 bar applicable.

It can also be used in particular different types of nozzles become. These include, in particular, single-substance nozzles, two-component nozzles (Liquid-gas, liquid-liquid), mixing inside or outside, different beam shapes, in particular flat jet nozzles and in particular Full cone nozzles.

In particular, flow rates in the ratio of less than 1: 5, in particular smaller than 1:10 and in particular smaller than 1:15 conceivable.

Figur 1

eine schematische Teildarstellung einer möglichen Ausführungsform einer Vorrichtung zum Besprühen einer Faserstoffbahn,

Figur 2

ein Funktionsschema zur Erläuterung der Funktionsweise eines Pulsationsventils,

Figur 3

ein Beispiel einer Kennlinie eines Pulsationsventils bei kontinuierlicher Volumenstromregelung im Vergleich zur entsprechenden Kennlinie eines Proportionalventils,

Figur 4

das Sprühbild einer Vollkegeldüse mit großer in Bahnlaufrichtung gemessener Sprühbreite im Vergleich zum Sprühbild einer Flachstrahldüse und

Figur 5

eine beispielhafte Verwendung einer unter einem Anstellwinkel entgegen der Bahnlaufrichtung sprühenden Flachstrahldüse.

The invention is explained in more detail below with reference to embodiments with reference to the drawing; in this show:

FIG. 1

FIG. 2 a schematic partial representation of a possible embodiment of a device for spraying a fibrous web, FIG.

FIG. 2

a functional diagram for explaining the operation of a pulsation valve,

FIG. 3

an example of a characteristic of a pulsation valve in continuous flow control in comparison to the corresponding characteristic of a proportional valve,

FIG. 4

the spray pattern of a full cone nozzle with large spray width measured in the web running direction compared to the spray pattern of a flat jet nozzle and

FIG. 5

an exemplary use of a spraying at an angle against the web running flat fan nozzle.

FIG. 1 shows a diagrammatic partial representation of a possible embodiment a device 10 for spraying a moving fibrous web 12. The fibrous web 12 may be in particular to act a paper or board web.

The device 10 comprises at least one nozzle 14, which is a preferably adjustable volume flow of the respective spray medium 16 supplied becomes. The nozzle 14 is preceded by at least one pulsation damper 18, to the volume flow of the spray medium 16 contained pulsations dampen.

The volume flow of the spray medium 16 is through a pulsation valve 20 set. This may, for example, an anchor valve and in particular to act a plate anchor valve. This pulsation valve 20 is driven via a control voltage U with a clock frequency f. In this case, the volume flow, for example via a pulse width modulation be varied. The clock frequency f is preferred in this case kept constant.

As can be seen from Figure 1, the pulsation valve 20 is the Spray medium 16 is supplied via a line 22. The pulsation damper 18 is in a line connecting the pulsation valve 20 to the nozzle 14 24 arranged. He is thus between the pulsation valve 20 and the nozzle 14.

In the lower right part of FIG. 1, the pulsation of the volumetric flow is shown shown in front of the pulsation damper 18. In comparison, is in the left the lower part of Figure 1, the pulsation of the volume flow after the Pulsation damper reproduced. In a comparison of the two pulsation diagrams It can be seen that in the flow of the spray medium 16 contained pulsation attenuated by the pulsation damper 18 becomes.

FIG. 2 shows a functional diagram for explaining the mode of operation of the pulsation valve 20. During a generally constant interval the duration T opens and closes the pulsation once the Flow, or it remains open continuously or closed throughout. The duration of the opening interval to can be varied. The Ratio to / T determines the opening duration of the pulsation valve. ever the longer the opening duration, the more liquid flows through the pulsation valve. Accordingly, the volume flow of the liquid can be regulated become. The first time diagram results with an opening duration of 50%, the second with an opening duration of 25% and the third with one Opening period of 75%.

FIG. 3 shows an example of a characteristic curve a of a pulsation valve continuous flow control compared to a corresponding Characteristic b of a proportional valve.

The unit shown in Figure 1 from pulsation valve 20, pulsation damper 18 and nozzle 14 is particularly in plants for spraying moving fibrous webs 12, in particular in spraying at Paper and board machines, in particular in steam dampers, Coating units, starch spraying installations, profiling installations and / or can be used. By the pulsation damper 18 is achieved the pulsations contained in the spray medium 16, as in particular are generated by a pulsation valve 20 are attenuated.

As a result, spray quantity fluctuations on the moving fibrous web reduced.

Instead of a pulsation damper or in addition, for example also be provided a flexible supply to the nozzle.

Moreover, it is possible, for example, a pulsating valve 20 in combination with a nozzle large spray width measured in the web running direction L. or depth. In this case, for example, a unit made Pulsation valve and nozzle measured in the direction of web travel Spray width or even a unit of pulsation valve, pulsation damper (and / or flexible supply) and nozzle large in the web running direction be provided measured spray width.

FIG. 4 shows the spray pattern A of such a nozzle 14 with a large spray width b ₁ measured in the web running direction _L , here for example a full cone nozzle, in comparison to the spray pattern B of a flat jet nozzle.

The parts A and B of Figure 4 show the spray pattern of the respective nozzle at the times t ₁ , t ₂ and t ₃ . The displacement of the respective spray pattern corresponds to the moving web. The shaded area of the respective spray pattern means that at this time the nozzle does not spray or only slightly. By contrast, the nozzle sprays in the non-hatched area of the respective spray pattern. It is thus reproduced the time course of the pulsation.

The spray pattern A results in a full cone nozzle with large in the web running direction measured spray width bi. The points P1 and P2 become from a spraying picture with spraying and a spraying picture without spraying overlaps. This leads despite a in the flow of the spray medium contained pulsation to a uniform spray pattern in the points P1 and P2 (see the right part of Figure 4A).

The spray pattern B results in a flat jet nozzle with small measured in the web running direction L spray width b _l . The points P1 and P2 are each overlapped only by a spraying image with a spray or a spray image without spraying. As a result, the pulsation contained in the volume flow of the spray medium is transferred completely to the spray pattern of the web 12 (compare the right-hand part of FIG.

Large spray widths bi measured in the web running direction L thus lead to a homogenization of the contained in the flow of the spray medium Pulsation when spraying the nozzle, as can be seen from a comparison of the two diagrams in the right part of FIGS. 4A and 4B, in FIG each of which the amount of spray over the web length is shown.

As a nozzle with a large spray width b ₁ measured in the web running direction, it is also possible, for example, to use an elliptical flat-jet nozzle instead of a full-cone nozzle.

Thus, a pulsation in the spray pattern contained in the volume flow is attenuated by a large measured in the web running direction spray width b _l , which is due to the fact that the moistening of a particular point on the moving web through the large spray width over a longer period. This compensates for volumetric flow fluctuations during this period at the point in question. The spray width b _{1 of} the respective nozzle measured in the web running direction can be, for example, greater than 30% of the spray width b _q measured in the web transverse direction.

As can be seen from FIG. 5, the nozzle 14 can be, for example, a nozzle Flat jet nozzle can be used, the α at an angle of attack Fiber web 12 against the web running direction L sprays. In the figure 5 the corresponding beam direction is denoted by SR. The angle of attack In particular, α may be less than about 80 °, and preferably less than be about 70 °.

It can be both a unit of pulsation valve and nozzle with large in Web running direction measured spray width and one unit Pulsation valve, pulsation damper (and / or flexible supply line) and Nozzle used with large spray width measured in web direction become. In both units can be used as a pulsation valve, for example Anchor valve such as in particular a plate anchor valve can be used. Both units are for example usable for spraying more agitated Fibrous webs, especially in spraying in paper and Board machines, in particular in nozzle moisteners, coating units, Stärkesprühanlagen, profiling and / or the like. By both Units can be measured as a nozzle with large in web direction Spray width bi, for example, an elliptical flat-jet nozzle or a Full cone nozzle be provided.

With a unit consisting of a pulsation valve, pulsation damper (and / or flexible supply line) and a nozzle with a large spray width b ₁ measured in the web running direction, moisture fluctuations due to spraying on the moving web are largely eliminated, so that such units can also be used in fast moving webs.

LIST OF REFERENCE NUMBERS

10

sprayer

12

Fibrous web

14

jet

16

spray medium

18

pulsation dampers

20

Valve

22

management

24

management

L

Web direction

SR

beam direction

b _l

spray width measured in the web running direction

b _q

measured in web transverse direction spray width

α

angle of attack

Claims (29)

1. Method for spraying a moving fibrous web (12), in particular a paper or board web, by means of at least one nozzle (14), in which the nozzle (14) is supplied with a preferably adjustable volume flow of the relevant spraying medium (16), characterized in that the spraying medium volume flow is supplied to the nozzle (14) via at least one pulsation valve (20), pulsations occurring in the volume flow of the spraying medium (16) being damped or attenuated.
2. Method according to Claim 1, characterized in that the volume flow supplied to the nozzle (14) is adjusted via the pulsation valve (20).
3. Method according to one of the preceding claims, characterized in that the pulsation valve (20) used is an armature valve.
4. Method according to Claim 3, characterized in that the pulsation valve (20) used is a plate armature valve.
5. Method according to one of the preceding claims, characterized in that pulsations occurring in the volume flow of the spraying medium (16) are damped or attenuated by means of at least one pulsation damper (18) connected upstream of the nozzle (14) and/or by using a nozzle (14) with a spraying width (b_l) which is appropriately large, as measured in the web running direction (L), and/or by using a flexible feed line (24') to the nozzle (14).
6. Method according to one of the preceding claims, characterized in that a nozzle (14) is used whose spraying width (b_l), measured in the web running direction (L), is at least 30% and preferably at least 50% of the spraying width (b_q) measured in the web transverse direction.
7. Method according to one of the preceding claims, characterized in that the nozzle (14) used is a preferably elliptical flat jet nozzle.
8. Method according to one of the preceding claims, characterized in that the nozzle (14) used is a flat jet nozzle, which sprays counter to the web running direction (L) at an angle of attack (α) with respect to the fibrous web (12), the angle of attack (α) being in particular smaller than about 80° and preferably smaller than about 70°.
9. Method according to Claim 8, characterized in that an appropriate flat jet nozzle is used at web speeds which are higher than, in particular, 1200 m/min and preferably higher than 1500 m/min.
10. Method according to one of Claims 1 to 6, characterized in that the nozzle (14) used is a solid-cone nozzle.
11. Method according to one of the preceding claims, characterized in that the volume flow supplied via the pulsation valve (20) is adjusted by means of pulse width modulation.
12. Method according to Claim 11, characterized in that the pulsation valve (20) is driven at a constant cycle frequency.
13. Method according to one of the preceding claims, characterized in that it is used in paper or board machines and in particular in nozzle moisteners, coating units, starch spraying installations, profiling installations and/or the like.
14. Device (10) for spraying a moving fibrous web (12), in particular a paper or board web, having at least one nozzle (14) to which a preferably adjustable volume flow of the relevant spraying medium (16) can be supplied, in particular for carrying out the method according to one of the preceding claims, characterized in that the spraying medium volume flow is supplied to the nozzle (14) via at least one pulsation valve (20), means (18, 14, 24') being provided to dampen or attenuate pulsations occurring in the volume flow of the spraying medium (16).
15. Device according to Claim 14, characterized in that the volume flow supplied to the nozzle (14) can be adjusted via the pulsation valve (20).
16. Device according to Claim 14 or 15, characterized in that the pulsation valve (20) provided is an armature valve.
17. Device according to Claim 16, characterized in that the pulsation valve (20) provided is a plate armature valve.
18. Device according to one of the preceding claims, characterized in that at least one pulsation damper (18) is connected upstream of the nozzle (14) and/or the nozzle (14) has a spraying width (b_l) which is appropriately large, as measured in the web running direction (L), and/or a flexible feed line (24') to the nozzle (14) is used, in order to damp or attenuate pulsations occurring in the volume flow of the spraying medium (16).
19. Device according to one of the preceding claims, characterized in that a nozzle (14) is provided whose spraying width (b_l), measured in the web running direction (L), is at least 30% and preferably at least 50% of the spraying width (b_q) measured in the web transverse direction.
20. Device according to one of the preceding claims, characterized in that the nozzle (14) provided is a preferably elliptical flat jet nozzle.
21. Device according to one of the preceding claims, characterized in that the nozzle (14) provided is a flat jet nozzle, which sprays counter to the web running direction (L) at an angle of attack (α) with respect to the fibrous web (12), the angle of attack (α) being in particular smaller than about 80° and preferably smaller than about 70°.
22. Device according to one of Claims 1 to 19, characterized in that the nozzle (14) provided is a solid-cone nozzle.
23. Device according to one of the preceding claims, characterized in that the volume flow supplied via the pulsation valve (20) can be adjusted by means of pulse width modulation.
24. Device according to Claim 23, characterized in that the pulsation valve (20) can be driven at a constant cycle frequency.
25. Device according to one of the preceding claims, characterized in that the flexible feed line (24') to the nozzle (14) is formed by a polyethylene, polyurethane or polyamide hose.
26. Device according to one of the preceding claims, characterized in that the flexible feed line (24') to the nozzle (14) has a length which is in particular greater than 3 m and preferably greater than 5 m.
27. Device according to one of the preceding claims, characterized in that a unit comprising pulsation valve (20) and pulsation damper (18) is provided.
28. Device according to one of the preceding claims, characterized in that a unit comprising pulsation valve (20), pulsation damper (18) and/or flexible feed line (24') and nozzle (14) is provided.
29. Use of the device according to one of the preceding claims in paper or board machines and in particular in nozzle moisteners, coating units, starch spraying installations, profiling installations and/or the like.

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