EP2106483B1 - Method and apparatus for drying a fibrous material web - Google Patents

Description

The invention relates to a method for drying a fibrous web, in particular paper, board or tissue web, in which the moving fibrous web is acted upon by hot air from a hot air hood in the region of a preceding predeterminable drying zone and fed to a downstream Yankee cylinder following the drying zone in which the fibrous web is further dried and wherein the hot air for the hot air hood assigned to the preceding drying zone is at least partially taken from the exhaust air of the hood associated with the downstream Yankee cylinder and the drying zone, essentially through the region It also relates to a corresponding machine for producing a fibrous web, in particular paper, board or tissue web.

In the WO 2005/075737 A1 A method is already described which serves to produce a voluminous tissue web and in which a so-called belt press in conjunction with a hot air hood or alternatively a steam hood for dewatering the fibrous web is used up to a certain dry content. With tissue machines, it is important to reduce energy consumption, especially during the drying process, to achieve a predefined dry content. On the other hand, there is a need for an increase in dry content with low energy consumption.

The document DE 2802156 B1 discloses a drying plant of a paper machine with an internally heated Trockerizytinder, and one as a suction roll trained pressure roller. The pressure roller is used to transfer a paper web from a guided over the roller felt belt on the surface of the drying cylinder. In the suction region of the suction roll, a device for supplying a heated gaseous medium for heating the paper web is provided. The medium may consist of the exhaust air of a hood associated with the drying cylinder.

In the document WO 2005/073461 a process for the preparation of through-dried tissue webs is described. The tissue webs are dried by a through-flow drying cylinder. It is provided to profile the dry content of the tissue web before the Durchströmtrockenzylinder transversely to Meschinenlaufrichtung. For profiling, humid exhaust air can be used.

The invention has for its object to provide an improved method and an improved machine of the type mentioned, in which the drying process, preferably for the aforementioned method for producing a tissue web, in particular with regard to the energy requirements for the dewatering of the fibrous web is optimized.

With regard to the method, this object is achieved in that the fibrous web is at least partially applied within the drying zone with steam and that the fibrous web is viewed in the web running direction, at least at the beginning of the drying zone to achieve a high dry content gain is applied to steam.

Advantageously, the hot air hood associated with the preceding drying zone can be supplied with drying air from a separate drying air source and this drying air fed to the hot air hood can be heated by hot air, in particular by means of a heat exchanger, which is taken from the hood or its exhaust air associated with the drying cylinder.

By the hot air for the hot air hood of the preceding drying zone is at least partially removed from the drying cylinder or its exhaust air, energy is recovered accordingly. Such energy recovery is possible because the temperature of the exhaust air from such hood associated with, for example, a Yankee cylinder is much higher than the temperature required for the hot air to supply the hot air hood to the preceding drying zone. Thus, the temperature of the hood of a drying cylinder such as in particular a Yankee cylinder removed hot air, for example, be about 300 ° C.

Preferably, the hot air hood of the preceding drying zone is at least partially supplied with hot air whose temperature in a range <250 ° C, ins particular <200 ° C and preferably in a range of about 150 ° C to about 200 ° C.

For drying the fibrous web, preferably tissue web, so hot air and steam is used in combination with each other.

Advantageously, the fibrous web is considered in the web running direction within the first half of the total length of the drying zone with steam.

The fibrous web, viewed in the web running direction, can first be subjected to steam and then to hot air. However, according to an alternative expedient embodiment, it is also possible, as viewed in the web running direction, first to apply the fibrous web with hot air, then with steam and then again with hot air.

In certain cases, it is advantageous if the fibrous web, viewed in the web running direction, is acted upon by steam over at least substantially the entire length of the drying zone.

However, according to an alternative expedient embodiment of the method according to the invention, it is also possible to apply steam to the fibrous web in the web running direction at least substantially only within the first half of the total length of the drying zone, in which case the fibrous web viewed in the web running direction preferably at least substantially Steam is applied only over the first half of the total length of the drying zone.

According to a further advantageous embodiment, the fibrous web is viewed in the web running direction at least substantially only within the first third of the total length of the drying zone, and thereby preferably at least substantially over this first third time away with steam applied.

In certain cases, it is also advantageous if the fibrous web is considered in the web running direction at least substantially only within the first quarter of the total length of the drying zone, and in this case preferably at least substantially over this first quarter away steam is applied.

According to a further alternative embodiment of the method according to the invention, the fibrous web, viewed in the web running direction, is acted upon with steam only at the beginning of the drying zone.

Preferably, the fibrous web is acted upon over the predetermined drying path away with hot air. At least in this case, the drying zone can be defined at least substantially by the area in which hot air is applied to the fibrous web. In this case, the fibrous web can be acted upon in particular within and / or before this drying zone with steam.

Conveniently, viewed in the web running direction, the fibrous web is subjected at least in some areas at the same time both to hot air and to steam. Under a simultaneous admission is to be understood in each case that a respective point of the fibrous web is acted upon both with hot air and with steam.

According to an expedient practical embodiment, the fibrous web, together with a permeable band, in particular structured band, are passed through the drying zone, in which case first the fibrous web and then the permeable band of the hot air or the steam, as far as it is not condensed in the web, are flowed through. The combined hot-air and steam application according to the invention can thus also be applied, for example, to a TAD-drying process.

A preferred alternative embodiment of the method according to the invention is characterized in that the fibrous web is passed through the drying zone together with at least one permeable band, in particular a structured band, whereby first the permeable band and then the fibrous web are flowed through by the hot air or the steam ,

In this case, the fibrous web in the drying zone can advantageously be covered by at least one further permeable band, in particular press belt, in which case first the further permeable band or press belt, then the first permeable band or structure band and finally the fibrous web of the hot air or hotfibre web The steam is flowed through. This results in the use of a press belt, a kind of belt press, in which then in addition to the mechanical pressure in particular the combined hot air and steam drying according to the invention is applied.

In addition, a dewatering belt, in particular felt belt, can be guided through the drying zone together with the fibrous web, wherein first the further permeable belt or press belt, then the first permeable belt or structure belt and the fibrous web and finally the additional dewatering belt from the hot air or the Steam to be flowed through, as far as this, as already mentioned, is not condensed in the web.

In principle, however, it is also conceivable to expose the fibrous web in the drying zone at least in regions to an impingement flow drying. In this case, therefore, the combined hot air and steam application according to the invention is used in the context of such an impingement flow drying.

In principle, however, the fibrous web can at least in some areas also be exposed to throughflow drying.

According to the invention, the object stated in the introduction is also achieved by a machine for producing a fibrous web, in particular paper, board or tissue web, with a preceding drying zone, in the region of which the moving fibrous web can be acted upon by hot air from a hot air hood, and with a downstream Yankee. Cylinder, with associated hood for further drying of the fibrous web, wherein the hot air for the preceding drying zone associated hot air hood is at least partially taken from the exhaust air of the downstream drying cylinder hood and the drying zone is essentially defined by the area in which the fibrous web with hot air is acted upon, said machine is characterized in that the fibrous web is at least partially acted upon by steam within the drying zone and that the fibrous web viewed in the web running direction, at least at the beginning of the drying Szone can be acted upon with steam to achieve a high dry content gain.

The hot air hood associated with the preceding drying zone is advantageously supplied with drying air from a separate drying stage source, this drying air fed to the hot air hood being heated by hot air, in particular by means of a heat exchanger, which is taken from the hood or its exhaust air associated with the drying cylinder.

As already mentioned, the corresponding energy recovery from the drying cylinder or the associated hood is possible because the temperature the exhaust air of this hood is much higher than the temperature required for the hot air to supply the hot air hood of the preceding drying zone. Thus, the temperature of the hood of a drying cylinder, in particular a Yankee cylinder, removed hot air, as already mentioned, for example, be about 300 ° C. Preferably, the hot air hood of the drying zone is at least partially supplied with hot air whose temperature is in a range <250 ° C, in particular <200 ° C and preferably in a range of about 150 ° C to about 200 ° C.

The temperature of the hot air for supplying the hot air hood can be adjusted and / or regulated in accordance with the energy consumption in order to optimize the operating point. A higher temperature would usually not result in more efficient drying.

Further preferred embodiments of the device according to the invention are specified in the subclaims.

In this case, preferably at least one hot air hood is provided for loading the fibrous web with hot air. In this case, the drying zone may be defined at least substantially in particular by the dimensions of the hot air hood. A steaming of the fibrous web is advantageously within and / or before the drying zone or hot air hood conceivable.

For impinging the fibrous web with steam, at least one steam blowing device, in particular steam blow pipe or steam blow box, is advantageously provided.

The steam blower expediently extends at least substantially over the entire width of the hot air hood measured transversely to the web running direction.

It is particularly advantageous if the steam blower is at least partially disposed within the hot air hood.

According to a preferred alternative embodiment, the steam blowing device can also be arranged directly in front of the hot air hood when viewed in the web running direction.

The relevant steam blower device can moreover be arranged, constructed and / or controlled so that the fibrous web, viewed in the direction of web travel, is acted upon by both hot air and steam at the same time over only a part of the total length of the drying zone or over the entire drying zone.

If the steam blower comprises a steam blow pipe, the diameter of the openings of this steam blow pipe is advantageously in a range of about 5 to about 1 mm, and preferably in a range of about 4 to about 2.5 mm. The diameter in question is preferably limited upwards, since a certain speed is required for the steam jet.

If the fibrous web in the area of the preceding drying zone is covered by at least one permeable belt, for example a permeable press belt, then the distance between the steam blower and the outer permeable belt covering the fibrous web, for example a press belt, is preferably <30 mm, in particular <20 mm , in particular <15 mm and preferably ≤ 10 mm.

If the steam blower device comprises a steam blower tube, its openings can advantageously be arranged at a mutual distance <20 mm, in particular <10 mm and preferably <7.5 mm.

If the steam blowing device comprises at least one steam blower box, the moisture transverse profile of the fibrous web can advantageously be adjusted and / or regulated via this.

If the steam blowing device comprises at least one steam blow pipe, the dry content of the fibrous web can be influenced or adjusted and / or regulated at least substantially via this steam blow pipe.

In principle, the steam blower device may comprise only at least one steam blow box or only at least one steam blow pipe or else at least one steam blow box or at least one steam blow pipe.

If the fibrous web is covered by at least one permeable band in the area of the preceding drying zone, means such as a scraper or the like are advantageously provided in order to remove the air boundary layer entrained with the outer permeable band covering the fibrous web prior to entry of the band into the drying area.

The flow rate (I / min) of the steam is preferably less than the flow rate (I / min) of the hot air. At atmospheric pressure, the flow rate of the vapor may advantageously be less than 0.5 times, in particular less than 0.3 times, and preferably less than 0.2 times, the flow rate of the hot air.

The steam causes an increase in the temperature of the fibrous web to reduce the viscosity of the water in the fibrous web. For this purpose, the steam in the fibrous web, in particular tissue web, must condense, since thereby the relevant temperature increase is achieved. This temperature increase can be adjusted for example by an appropriate choice of the correct temperature level for the hot air.

The temperature of the hot air impinging on the fibrous web is thus preferably adjustable, in particular for influencing the condensation of the steam in the fibrous web.

If the temperature is too low, the steam condenses immediately before entering the fibrous web. This is because the steam is cooled by the housing of the hot air hood and by the incoming colder bands. This may occur in particular in the case of the use of a so-called belt press, since in this case the steam first has to penetrate two outer bands, namely the outer permeable band, in particular press belt, and optionally a permeable structured band, before it enters the fibrous web.

If the fibrous web is covered by a permeable press belt in the drying zone, this advantageously has a permeability of> 170 m ³ / h (100 cfm), in particular> 510 m ³ / h (300 cfm), in particular> 850 m ³ / h (500 cfm) and preferably> 1189 m ³ / h (700 cfm) (cfm = cubic feet per minute).

If the fibrous web led together with a permeable structured belt through the drying zone so owns this preferably has a permeability of> 170 m ³ / h (100 cfm) (100 cfm), in particular 510 m ³ / h (300 cfm), in particular 850 m ³ / h (> 500 cfm) and preferably> 1189 m ³ / h (700 cmf).

It is particularly advantageous if the fibrous web is covered in the preceding drying zone by a permeable press belt, which consists at least substantially of plastic, in particular polyamide, polyethylene, polyurethane, etc.

However, according to an alternative expedient embodiment of the machine according to the invention, the fibrous web in the preceding drying zone can also be covered by a permeable pressing belt, which is formed by a metal strip.

Preferably, at least one belt guided through the drying zone together with the fibrous web is preheated in the web running direction in front of the drying zone. This is particularly useful in the case that a metal existing press belt is used.

For preheating advantageously a steam heater, an IR heater and / or a hot water heater is used.

A hot-water heating device is particularly suitable for an inner band guided through the drying zone together with the fibrous web, in particular an additional dewatering belt.

As already mentioned, the air separation layer entrained on the surface of the outer band may expediently be removed, for example, by means of a scraper extending over the width thereof in front of the hot air hood. This also brings a correspondingly higher temperature after it is avoided that the steam is cooled before entering the fibrous web. The temperature of the hot air can thus be chosen lower.

Fig. 1

eine schematische Darstellung einer herkömmlichen, nur mit Dampf arbeitenden Trocknungsvorrichtung sowie des entsprechenden Trockengehaltszuwachses und des entsprechenden Temperaturverlaufs,

Fig. 2

eine schematische Darstellung einer herkömmlichen, nur mit Heißluft arbeitenden Trocknungsvorrichtung sowie des entsprechenden Trockengehaltszuwachses und des entsprechenden Temperaturverlaufs,

Fig. 3

eine schematische Darstellung einer beispielhaften Ausführungsform einer erfindungsgemäßen Maschine zur Herstellung einer Tissuebahn mit einer erfindungsgemäßen Trockriungsvorrichtung und

Fig. 4

eine vereinfachte schematische Darstellung einer abgewandelten Ausführungsform der erfindungsgemäßen Trocknungsvorrichtung sowie des entsprechenden Trockengehaltszuwachses und des entsprechenden Temperaturverlaufs.

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

Fig. 1

a schematic representation of a conventional, only working with steam drying device and the corresponding dry content gain and the corresponding temperature profile,

Fig. 2

a schematic representation of a conventional, working only with hot air drying device and the corresponding dry content gain and the corresponding temperature profile,

Fig. 3

a schematic representation of an exemplary embodiment of a machine according to the invention for producing a tissue web with a Trockriungsvorrichtung invention and

Fig. 4

a simplified schematic representation of a modified embodiment of the drying device according to the invention and the corresponding dry content increase and the corresponding temperature profile.

Fig. 1 Fig. 1 schematically shows a conventional steam-only drying apparatus having a suction roll 12 having a suction zone 10 and a steam blowing box 14 opposite to the suction zone 10 in the starting region. The tissue web 16 is interposed between an inner dewatering belt 18 or felt and a structured belt 20 together with a outer, here made of metal press belt passed over the suction roller 12.

The bands 18 to 20 are each permeable. The press belt 22 is guided over guide rollers 24 and presses the belts 18 to 22 and the tissue web 16 in the region of the suction zone 10 against the suction roller 12.

In the area of the steam blow box, the temperature T increases. Following this, however, the tissue web 16 already cools down strongly within the suction zone 10 with the intake ambient air. As is clear from the Fig. 1 results in a dry content increase of about 0.2%, and only in the area of the steam blower box 14.

Fig. 2 shows a schematic representation of a conventional, working only with hot air drying device. This drying apparatus comprises a suction roller 12 having a suction zone 10 and a hot air hood 26 extending opposite the suction zone 10 over its entire length viewed in the web running direction L. The tissue web 16 is again comprised between a permeable dewatering belt 18 or felt and a permeable structured belt 20 with an outer permeable press belt 22 made of metal over the suction zone 10 of the suction roll 12.

The dry content increment D in this drying apparatus, in which the tissue web 16 is dried by the hot air flowing therethrough, is about 1.5%. The temperature T increases in the region of the suction zone 10 and the hot air hood 26 only slightly.

Fig. 3 shows a schematic representation of an exemplary embodiment of a machine according to the invention 28 for producing a fibrous web, here for example a tissue web with a drying device 30 according to the invention.

The drying device 30 comprises a suction roll 32 having a suction zone 34 defined in particular by an integrated suction box and a hot air hood 36 assigned to the suction roll 32.

In this case, the fibrous web 38, here for example tissue web, is guided together with a permeable structured band 40 over the suction roll 32, the fibrous web 38 lying between the permeable structured band 40 and the suction roll 32. In addition, in the area of the suction zone 34 outside, a high-pressure permeable pressing belt 80 is wound around the suction roll 32, whereby a belt press is formed. This in the Fig. 1 only indicated press belt 80 is in the Fig. 4 to recognize even more clearly. The hot air from the hot air hood 36 thus flows successively through the permeable press belt 80, the permeable structured belt 40 and the fibrous web 38 into the suction zone 34 of the suction roller 32.

In addition, a dewatering belt 42, e.g. Felt, led to the suction roll 32, which is between the suction roll 32 and the permeable structured band 40 and through which the hot air flows into the suction zone 34 of the suction roll 32. In the present embodiment, therefore, the permeable press belt 80, the permeable structured belt 40, the fibrous web 38 and the dewatering belt 42 are successively flowed through by the hot air.

The running fibrous web 38 is thus subjected to hot air in the region of the drying device 30 over a preceding drying zone, wherein this drying zone can be determined at least substantially by the hot air hood 36. In this case, this drying zone, viewed in the web running direction L, may for example extend at least essentially over the suction zone 34 of the suction roll 32 or, for example, beyond it.

Subsequent to the preceding drying zone provided in the area of the drying device 30, the fibrous web 38 is fed to a downstream drying cylinder 60, in particular Yankee cylinder, to which a further hood 66 is assigned and in whose area the fibrous web 38 is further dried.

According to the invention, the hot air for the hot air hood assigned to the preceding drying zone is at least partially taken from the hood assigned to the downstream drying cylinder 60. In this case, the hot air for the preceding drying zone associated hot air hood 36 at least partially the exhaust air of the downstream drying cylinder 60 associated hood 66 are removed.

For example, drying air supplied from a separate drying air source can also be supplied to the drying air hood associated with the preceding drying zone, and this drying air supplied to the hot air hood can then be heated by hot air, in particular by means of a heat exchanger, which is taken from the hood or its exhaust air assigned to the drying cylinder ,

The hot air taken from the hood 66 of the drying cylinder 60 may, for example, have a temperature of about 300 ° C.

The hot air hood 36 can be at least partially supplied in particular with hot air whose temperature is in a range <250 ° C, in particular in a range <200 ° C and preferably in a range of about 150 ° C to about 200 ° C.

Advantageously, the fibrous web 38 is supplied with hot air in the region of the dryer zone 60 preceding drying zone and at least partially with steam.

This can be the. Fiber web 38 viewed in the web running direction L, at least at the beginning of the drying zone to be acted upon with steam. According to the present embodiment Fig. 3 is the fibrous web 38 viewed in the web running direction L only at the beginning of this drying zone exposed to steam. It is considered in the web running direction first with steam and then applied with hot air.

For impinging the fibrous web 38 with steam, at least one steam blower 44, in particular a steam blower pipe or steam blower box, is provided. In the present case, this steam blower 44 comprises a steam blow pipe, preferably provided at the beginning of the drying zone.

The steam blower 44 may extend at least substantially over the entire width of the hot air hood 36 measured transversely to the web running direction L. Advantageously, it is at least partially disposed within the hot air hood 36.

For example, based on the Fig. 4 can be seen, the steam blower 44, for example, include at least one steam blower box. Also in this case the steam blower box is again located at the beginning of the drying zone defined here at least substantially by the hot air hood 36 and at least substantially inside the hot air hood 36. Also in this case, the fibrous web 38 is thus initially charged with steam and then with hot air.

As based on the Fig. 3 can be seen, means such as a scraper 46 or the like may be provided to dissipate with the outer the fibrous web 38 covering the permeable structured band 40 entrained air separation layer before an entry of the belt 40 in the drying zone.

The machine 28 further comprises a former with two converging drainage belts 40, 48, wherein the inner belt simultaneously forms the permeable structured belt 40 in the present case. The two dewatering belts 40, 48 merge to form a pulp inlet gap 50 and are guided over a forming element 52 such as in particular a forming roller.

In the present case, therefore, the permeable structured band 40 is formed by the inner dewatering band of the former coming into contact with the forming element 52. The outer dewatering belt 48, which does not come into contact with the forming element 52, is separated again from the fibrous web 38 following the forming element 52.

By means of a headbox 54, the pulp suspension is introduced into the stock inlet gap 50.

Between the forming element 52 and the drying device 30, a suction element 56 may be provided, through which the fibrous web 38 is held on the permeable structured band 40 or pressed against this permeable structured band 40.

Following the drying device 30, the dewatering belt 42 is again separated from the permeable structured belt 40. In this case, behind the drying device 30, a pickup or separating element 58 is provided, through which the fibrous web 38 is held at the separation of the dewatering belt 42 to the permeable structured band 40.

Subsequently, the fibrous web 38, together with the permeable structured band 40, is guided through a press nip 64 formed between the drying cylinder 60, which is preferably formed by a Yankee cylinder, and a pressing element 62 such as a press roller. The pressing element 62 in the present case is, for example, a shoe press roll. Behind the press nip 64, the permeable structured band 40 is again separated from the drying cylinder 60, while the fibrous web 38 remains on the drying cylinder 60. The drying cylinder 60, the hood 66 is associated.

Optionally, a vacuum box with a hot air hood 68 or the like may be provided between the suction roll 32 and the drying cylinder 60 to increase the sheet strength.

As already mentioned, the hot air for the suction roll 32 associated hot air hood 36 may be at least partially removed from the drying cylinder 60 associated hood 66. The hot air taken from this hood 66 has a temperature, for example in the range of about 300 ° C, which is generally higher than the temperature required for the hot air of the hot air box 36.

As based on the Fig. 3 can be seen, the hot cylinder associated with the drying cylinder hood 66 removed hot air of the hot air hood 36 can be supplied via a feed line 70, in which at least one valve 72, in particular control valve can be arranged. In addition, in this supply line 70, if necessary, a filter 74 may be provided for the removal of in particular short fibers, dust or the like. Finally, in this supply line 70, a fan may be arranged.

The hot air taken from the hood 60 associated with the cylinder 60 can also be mixed with cold air supplied via a line 76. Also in the line 76 for the supplied cold air again at least one valve 78, in particular control valve may be provided. About the mixing ratio of the hood 66 removed hot air and the cold air so the temperature of the hot air hood 36 supplied air can be adjusted.

Fig. 4 shows a simplified schematic representation of a modified embodiment of the drying device 30 according to the invention. As already mentioned, here the steam blower 44 comprises instead of a steam blow pipe at least substantially within the hot air hood 36 arranged steam blower box. This steam blower box, viewed in the web running direction L, is again provided at the beginning of the drying zone defined here at least essentially by the hot air hood 36.

The present embodiment differs from that of the Fig. 3 moreover, in that, in addition to the permeable structured belt 40 and the dewatering belt 42 or felt, a permeable press belt 80 is fed together with the fibrous web 38 through the drying zone, through which the permeable structured belt 40, the fibrous web 38 and the permeable dewatering belt 42 in the the suction zone 34 are pressed against the suction roller 32.

The press belt 18 is viewed in the web running direction L before and behind the drying zone each guided around a guide roller 82, via which the relevant voltage for the press belt 80 is generated.

As based on the Fig. 4 can be seen, results in relation to the entire suction zone, which defines the drying zone here at the same time, a relatively high temperature T. Accordingly, there is also a relatively high dry content gain, here for example about 3%, a.

LIST OF REFERENCE NUMBERS

10

suction zone

12

suction roll

14

steam blow

16

tissue web

18

dewatering belt

20

structured band

22

press belt

24

guide roll

26

Hot air hood

28

machine

30

drying device

32

vacuumed device, suction roller

34

suction zone

36

Hot air hood

38

Fibrous web, in particular tissue web

40

permeable structured band

42

dewatering belt

44

Steam blower, steam pipe, steam box

46

scraper

48

dewatering belt

50

Stock inlet gap

52

Forming element, forming roller

54

headbox

56

suction

58

Pickup or separating element

60

Drying cylinder, Yankee cylinder

62

press member

64

press nip

66

Hood

68

Hot air hood

70

supply

72

Valve

74

filter

76

management

78

Valve

80

permeable press belt

82

guide roll

Claims (72)

1. Method for drying a fibrous material web (38), in particular a paper, cardboard, or tissue web, in which the moving fibrous material web (38) is subjected, in the region of a specifiable upstream drying zone, to hot air from a hot air hood (36), and subsequent to the drying zone is fed to a downstream Yankee cylinder (60), to which a further hood (66) is assigned, and in the region of which the fibrous material web (38) is dried further, wherein the hot air for the hot air hood (36) assigned to the upstream drying zone is at least partially taken from the exhaust air of the hood (66) assigned to the downstream Yankee cylinder (60), and the drying zone is essentially defined by the region in which the fibrous material web is subjected to hot air,
   characterized in that
   the fibrous material web (38) within the drying zone is at least in some regions subjected to steam, and in that the fibrous material web (38), as viewed in the web direction of movement (L), is subjected to steam, at least at the start of the drying zone, for purposes of achieving a high gain in dry content.
2. Method according to Claim 1,
   drying air from a separate drying air source is fed to the hot air hood (36) assigned to the upstream drying zone, and the said drying air fed to the hot air hood (36) is heated, in particular by means of a heat exchanger, by hot air that is extracted from the hood (66) assigned to the drying cylinder (60), that is to say, from its exhaust air.
3. Method according to one of the preceding claims,
   characterized in that
   the hot air extracted from the hood (66) of the drying cylinder (60) possesses a temperature of approximately 300 °C.
4. Method according to one of the preceding claims,
   characterized in that
   the hot air hood (36) is at least partially supplied with hot air, the temperature of which lies in a range < 250 °C, in particular < 200 °C, and preferably in a range of approximately 150 °C to approximately 200 °C.
5. Method according to Claim 1,
   characterized in that
   the fibrous material web (38), as viewed in the web direction of movement (L), is subjected to steam within the first half of the overall length of the drying zone.
6. Method according to one of the preceding claims,
   characterized in that
   the fibrous material web (38), as viewed in the web direction of movement (L), is subjected firstly to steam, and subsequently to hot air.
7. Method according to one of the Claims 1 to 5,
   characterized in that
   the fibrous material web (38), as viewed in the web direction of movement (L), is subjected firstly to hot air, subsequently to steam, and after that once again to hot air.
8. Method according to one of the preceding claims,
   characterized in that
   the fibrous material web (38), as viewed in the web direction of movement (L), is subjected to steam at least essentially over the overall length of the drying zone.
9. Method according to one of the Claims 1 to 7,
   characterized in that
   the fibrous material web (38), as viewed in the web direction of movement (L), is subjected to steam at least essentially only within the first half of the overall length of the drying zone.
10. Method according to Claim 9,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), is subjected to steam at least essentially over the first half of the overall length of the drying zone.
11. Method according to one of the Claims 1 to 7,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), is subjected to steam at least essentially only within the first third of the overall length of the drying zone.
12. Method according to Claims 1 to 7,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), is subjected to steam at least essentially over the first third of the overall length of the drying zone.
13. Method according to one of the Claims 1 to 7,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), is subjected to steam at least essentially only within the first quarter of the overall length of the drying zone.
14. Method according to one of the Claims 1 to 7,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), is subjected to steam at least essentially over the first quarter of the overall length of the drying zone.
15. Method according to one of the Claims 1 to 7,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), is subjected to steam only at the start of the drying zone.
16. Method according to one of the preceding claims,
    characterized in that
    the fibrous material web (38) is subjected to hot air over the specifiable drying zone.
17. Method according to one of the preceding claims,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), is subjected simultaneously to both hot air and steam in at least some regions.
18. Method according to one of the preceding claims,
    characterized in that
    the fibrous material web (38), is fed together with a permeable belt, in particular a structured belt, through the drying zone, wherein the hot air and/or steam flows firstly through the fibrous material web, and subsequently through the permeable belt.
19. Method according to one of the Claims 1 to 17,
    characterized in that
    the fibrous material web (38) is fed together with at least one permeable belt (40), in particular a structured belt, through the drying zone, wherein the hot air and/or steam flows firstly through the permeable belt (40), and subsequently through the fibrous material web (38).
20. Method according to Claim 19,
    characterized in that
    in the drying zone the fibrous material web is covered by at least one further permeable belt (80), in particular a pressure application belt, wherein the hot air and/or steam flows firstly through the further permeable belt (80), or pressure application belt, subsequently through the first permeable belt (40), or structured belt, and finally through the fibrous material web (38).
21. Method according to Claim 19 or 20,
    characterized in that
    an additional water removal belt (42), in particular a felt belt, is fed together with the fibrous material web (38) through the drying zone, wherein the hot air and/or steam flows firstly, where applicable, through the further permeable belt (80), or pressure application belt, subsequently through the first permeable belt (40), or structured belt, and through the fibrous material web (38), and finally through the additional water removal belt (42).
22. Method according to one of the preceding claims,
    characterized in that
    in the drying zone the fibrous material web (38) is subjected to a baffle flow drying process in at least some regions.
23. Method according to one of the preceding claims,
    characterized in that
    in the drying zone the fibrous material web (38) is subjected to a through flow drying process in at least some regions.
24. Machine for the manufacture of a fibrous material web (38), in particular a paper, cardboard, or tissue web, with a specifiable upstream drying zone, in the region of which the moving fibrous material web (38) can be subjected to hot air from a hot air hood (36), and with a downstream Yankee cylinder (60), to which a hood (66) is assigned for purposes of drying of the fibrous material web (38), in particular for purposes of executing the method according to one of the preceding claims, wherein the hot air for the hot air hood (36) assigned to the upstream drying zone is at least partially taken from the exhaust air of the hood (66) assigned to the downstream drying cylinder (60), and the drying zone is essentially defined by the region in which the fibrous material web is subjected to hot air,
    characterized in that
    within the drying zone the fibrous material web (38) can be subjected to steam in at least some regions, and in that the fibrous material web (38), as viewed in the web direction of movement (L), can be subjected to steam, at least at the start of the drying zone, for purposes of achieving a high gain in dry content.
25. Machine according to Claim 24,
    characterized in that
    drying air from a separate drying air source is fed to the hot air hood (36) assigned to the upstream drying zone, and the said drying air fed to the hot air hood (36) is heated, in particular by means of a heat exchanger, by hot air that is extracted from the hood (66) assigned to the drying cylinder (60), that is to say, from its exhaust air.
26. Machine according to one of the preceding Claims 24 to 25,
    characterized in that
    the hot air extracted from the hood (66) of the drying cylinder (60) possesses a temperature of approximately 300 °C.
27. Machine according to one of the preceding Claims 24 to 26,
    characterized in that
    the hot air hood (36) is at least partially supplied with hot air, the temperature of which lies in a range < 250 °C, in particular < 200 °C, and preferably in a range of approximately 150 °C to approximately 200 °C.
28. Machine according to Claim 24,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), can be subjected to steam within the first half of the overall length of the drying zone.
29. Machine according to Claim 28,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), can be subjected firstly to steam, and subsequently to hot air.
30. Machine according to Claim 28,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), can be subjected firstly to hot air, subsequently to steam, and after that once again to hot air.
31. Machine according to Claim 24,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), can be subjected to steam at least essentially over the overall length of the drying zone.
32. Machine according to one of the Claims 28 to 30,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), can be subjected to steam at least essentially only within the first half of the overall length of the drying zone.
33. Machine according to Claim 32,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), can be subjected to steam at least essentially over the first half of the overall length of the drying zone.
34. Machine according to one of the Claims 28 to 30,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), can be subjected to steam at least essentially only within the first third of the overall length of the drying zone.
35. Machine according to one of the Claims 28 to 30,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), can be subjected to steam at least essentially over the first third of the overall length of the drying zone.
36. Machine according to one of the Claims 28 to 30,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), can be subjected to steam at least essentially only within the first quarter of the overall length of the drying zone.
37. Machine according to one of the Claims 28 to 30,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), can be subjected to steam at least essentially over the first quarter of the overall length of the drying zone.
38. Machine according to one of the Claims 28 to 30,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), can be subjected to steam only at the start of the drying zone.
39. Machine according to one of the preceding Claims 24 to 38,
    characterized in that
    the fibrous material web (38) is subjected to hot air over the specifiable drying zone.
40. Machine according to one of the preceding Claims 24 to 39,
    characterized in that
    the fibrous material web (38), as viewed in the web direction of movement (L), is subjected simultaneously to both hot air and steam in at least some regions.
41. Machine according to one of the preceding Claims 24 to 40,
    characterized in that
    the fibrous material web (38) is fed together with a permeable belt, in particular a structured belt, through the drying zone, wherein the hot air and/or steam flows firstly through the fibrous material web, and subsequently through the permeable belt.
42. Machine according to one of the Claims 28 to 38,
    characterized in that
    the fibrous material web (38) is fed together with at least one permeable belt (40), in particular a structured belt, through the drying zone, wherein the hot air and/or steam flows firstly through the permeable belt (40), and subsequently through the fibrous material web (38).
43. Machine according to Claim 42,
    characterized in that
    in the drying zone the fibrous material web (38) is covered by at least one further permeable belt (80), in particular a pressure application belt, wherein the hot air and/or steam flows firstly through the further permeable belt (80), or pressure application belt, subsequently through the first permeable belt (40), or structured belt, and finally through the fibrous material web (38).
44. Machine according to Claim 42 or 43,
    characterized in that
    an additional water removal belt (42), in particular a felt belt, is fed together with the fibrous material web (38) through the drying zone, wherein the hot air and/or steam flows firstly, where applicable, through the further permeable belt (80), or pressure application belt, subsequently through the first permeable belt (40), or structured belt, and through the fibrous material web (38), and finally through the additional water removal belt (42).
45. Machine according to one of the preceding Claims 24 to 44,
    characterized in that
    at least one hot air hood (36) is provided for purposes of subjecting the fibrous material web (38) to hot air.
46. Machine according to one of the preceding Claims 28 to 45,
    characterized in that
    at least one steam blower device (44), in particular a steam blower pipe, or a steam blower box, is provided for purposes of subjecting the fibrous material web (38) to steam.
47. Machine according to Claim 46,
    characterized in that
    the steam blower device (44) extends at least essentially over the total width of the hot air hood (36), measured at right angles to the web direction of movement.
48. Machine according to Claim 46 or 47,
    characterized in that
    the steam blower device (44) is arranged at least partially within the hot air hood (36).
49. Machine according to Claim 46 or 47,
    characterized in that
    the steam blower device (44), as viewed in the web direction of movement (L), is arranged directly upstream of the hot air hood (36).
50. Machine according to one of the preceding Claims 46 to 49,
    characterized in that
    the steam blower device (44) comprises at least one steam blower pipe with openings; its diameter lies in a range from approximately 5 to approximately 1 mm, and preferably in a range from approximately 4 to approximately 2.5 mm.
51. Machine according to one of the preceding Claims 46 to 50,
    characterized in that
    in the region of the drying zone the fibrous material web is covered with at least one permeable belt (40), and in that the distance between the steam blower device (44) and the outer permeable belt (38) covering the fibrous material web is < 30 mm, in particular < 20 mm, in particular < 15 mm, and is preferably 10 mm.
52. Machine according to one of the preceding Claims 46 to 51,
    characterized in that
    the steam blower device (44) comprises at least one steam blower pipe with openings, which are arranged at mutual distances of < 20 mm, in particular of < 10 mm, and preferably of < 7.5 mm.
53. Machine according to one of the preceding Claims 46 to 52,
    characterized in that
    the steam blower device (44) comprises at least one steam blower box, and via the latter the transverse moisture profile of the fibrous material web (38) can be adjusted and/or regulated.
54. Machine according to one of the preceding Claims 46 to 53,
    characterized in that
    the steam blower device (44) comprises at least one steam blower pipe, and the dry content of the fibrous material web (38) can be influenced, or can be adjusted and/or regulated, at least essentially via the said steam blower pipe.
55. Machine according to one of the preceding Claims 24 to 54,
    characterized in that
    in the region of the drying zone the fibrous material web (38) is covered with at least one permeable belt (40), and in that means are provided, in particular such as a scraper (46) or similar, in order to remove the air boundary layer carried along with the outer permeable belt (40) covering the fibrous material web (38), before the entry of the belt into the drying zone.
56. Machine according to one of the preceding Claims 24 to 55,
    characterized in that
    in the region of the drying zone at least one suction device (32), in particular a suction box and/or suction roller, is arranged on the side of the fibrous material web (38), or the additional water removal belt, facing away from the hot air hood (36).
57. Machine according to Claim 56,
    characterized in that
    the suction device comprises a suction roller (32) with a suction box defining a suction zone.
58. Machine according to Claim 43,
    characterized in that
    the further permeable belt is formed by a pressure application belt (80), which is subject to a high tension, preferably in a range from approximately 40 to approximately 60 kN/m, and thereby applies a pressure in a pressure application zone, which preferably lies in a range from approximately 0.5 to approximately 1.5 bar.
59. Machine according to Claim 58,
    characterized in that
    the length, as viewed in the web direction of movement (L), of the pressure application zone formed by the permeable pressure application belt (80), is at least essentially defined by the contact region, over which the pressure application belt (80) makes contact with the suction roller.
60. Machine according to one of the preceding Claims 58 to 59,
    characterized in that
    the length, as viewed in the web direction of movement (L), of the pressure application zone formed by the permeable pressure application belt (80), corresponds at least essentially to the length of the suction zone of the suction roller.
61. Machine according to one of the preceding Claims 58 to 60,
    characterized in that
    the drying zone, as viewed in the web direction of movement (L), is shorter than the pressure application zone.
62. Machine according to one of the Claims 58 to 59,
    characterized in that
    the drying zone, as viewed in the web direction of movement (L), is equal to or longer than the pressure application zone.
63. Machine according to one of the preceding Claims 28 to 62,
    characterized in that
    the flow rate (l/min) of the steam is less than the flow rate (l/min) of the hot air.
64. Machine according to Claim 63,
    characterized in that
    at atmospheric pressure the flow rate of the steam is less than 0.5 times, in particular less than 0.3 times, and preferably less than 0.2 times, the flow rate of the hot air.
65. Machine according to one of the preceding Claims 24 to 64,
    characterized in that
    the temperature of the hot air impacting on the fibrous material web (38) can be adjusted, in particular for purposes of influencing the condensation of the steam in the fibrous material web (38).
66. Machine according to one of the preceding Claims 24 to 65,
    characterized in that
    in the drying zone the fibrous material web (38) is covered by a permeable pressure application belt (80), which possesses a permeability of > 170 m³/h (100 cfm), in particular > 510 m³/h (300 cfm), in particular > 850 m³/h (500 cfm) and preferably > 1189 m³/h (700 cfm).
67. Machine according to one of the preceding Claims 24 to 66,
    characterized in that
    the fibrous material web (38) is fed through the drying zone together with a permeable structured belt (40), which possesses a permeability of > 170 m³/h (100 cfm), in particular > 510 m³/h (300 cfm), in particular > 850 m³/h (500 cfm) and preferably > 1189 m³/h (700 cfm).
68. Machine according to one of the preceding Claims 24 to 67,
    characterized in that
    in the drying zone the fibrous material web (38) is covered by a permeable pressure application belt (80), which at least essentially consists of a plastic, in particular polyamide, polyethylene, or polyurethane.
69. Machine according to one of the Claims 28 to 68,
    characterized in that
    in the drying zone the fibrous material web (38) is covered by a permeable pressure application belt (80), which is formed by a metal belt.
70. Machine according to one of the preceding Claims 24 to 69,
    characterized in that
    at least one belt (80, 40, 42), fed together with the fibrous material web (38) through the drying zone, is preheated upstream of the drying zone in the web direction of movement (L).
71. Machine according to Claim 70,
    characterized in that
    a steam heating device an IR heating device, and/or a hot water heating device, is provided for purposes of preheating.
72. Machine according to Claim 70 or 71,
    characterized in that
    at least one inner belt (42), such as in particular the additional water removal belt, fed together with the fibrous material web (38) through the drying zone, can be preheated by means of a hot water heating device.

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