METHOD FOR DRYING A FIBROUS WEB IN A DRYING DEVICE, AND DRYING DEVICE

Abstract

A method for drying a fibrous web in a drying device and to a corresponding drying device is provided, in which the fibrous web is guided in an open draw with multiple deflections through the drying device through a plurality of intermediate drying spaces which are arranged parallel to one another and define web-guiding path sections, and is loaded on both sides with a drying medium, in particular hot air, for thermal transfer. The fibrous web is guided through the drying device alternately in the vertical direction in and counter to the direction of and gravity, and vice versa.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of PCT application No. PCT/EP2012/055483, entitled “METHOD FOR DRYING A FIBROUS WEB IN A DRYING DEVICE, AND DRYING DEVICE”, filed Mar. 28, 2012, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device and a method for drying a fibrous web.

2. Description of the Related Art

Generic drying devices which operate according to the impingement principle with hot air are already known in the state of the art in various arrangements in the embodiment of horizontal-air drying devices. In these devices the fibrous web which is to be dried is guided through the drying device through drying spaces which are arranged horizontally aligned and arranged in a vertical direction on top of one another. The fibrous web runs through the individual drying spaces consecutively horizontally from the infeed side of the drying device to the outfeed side, whereby the redirection of the fibrous web occurs through reversal between two drying spaces which are arranged above one another, with the assistance of turn rollers which are arranged on the infeed side and the outfeed side. The drying spaces are hereby defined by blower devices which are arranged on both sides of and at a distance from the theoretical web guidance path of the fibrous web. The fibrous web is treated on both sides with hot air in the drying spaces. The hot air supplied for this purpose by the blower devices serves as a heat transfer to the fibrous web. Due to the long web guidance path segments in the horizontal direction in such drying devices, it is necessary—in order to avoid excessive stress in the gravitational direction between the turn rollers which are arranged on both sides of a drying space—to support the fibrous web in this region by means of an air cushion. Stable operating conditions for the horizontal pass through the drying spaces can hereby only be ensured through low flow speeds of the drying medium which is to be applied, through special geometries of the discharge openings, in particular in the blower devices arranged below and acting upon the fibrous web, as well as through different distances between the discharge openings of the blower devices arranged above and below an individual web guidance path segment, or respectively the fibrous web. Since the blower device arranged below a web guidance path segment serves to form the necessary air cushion, the design, in particular the geometry, of the discharge openings of the blower device, their configuration and operational parameters, as well as the operational parameters and state variables of the drying medium, are to be adapted to this function. The layout, the design and the operating parameters of the blower device above the web guidance path segment acting on the other side of the fibrous web is to be selected so that this does not affect the formation of the air cushion. The possibility of a purposeful profiling of the drying medium to be applied onto the fibrous web side facing in the gravitational direction is not possible under these conditions. The greater distance of the blower devices disposed above a web guidance path segment impairs the heat exchange.

Due to the additionally required support for the fibrous web over each individual web guidance path segment a control of the drying rate over an individual web guidance path segment is not possible. Because of the multi-function of the drying medium which is applied to the fibrous web, only low drying rates are achievable.

An additional disadvantage with horizontal web guidance is that in the event of a web break, the web can only be removed from the drying spaces with difficulty and at great expense. Special devices are hereby required to avoid contamination of the individual blower devices as well as for their protection, for example in the form of grating.

Another drying device operating according to the impingement principle with hot air and with vertical fibrous web guidance which is arranged downstream of a pulp press is known from publication DE 699 09 999 T2. In this case however, a pulp having a very low dry content is guided through the drying device, continuously supported on a fabric belt.

What is needed in the art is a more effective and efficient method for drying a fibrous web and an associated drying device so that the aforementioned disadvantages are avoided. In particular, a drying device is needed in the art which is characterized by simple fibrous web guidance and at the same time easily realizable active control/adjustment of the drying rate along the web path, as well as a high drying rate in a small space. The individual drying spaces should be easily accessible and the fibrous web should be easily removable from them in the event of a web break. The engineering effort should be kept low.

SUMMARY OF THE INVENTION

The present invention provides a device and a method for drying a fibrous web which allows for control/adjustment of the drying rate along the web path and easy removal from individual drying spaces in the event of a web break. According to the present invention, the fibrous web is guided in an open draw with multiple redirection through the drying device, through a plurality of drying spaces which are arranged parallel to each other and represent web guiding path sections. The web is treated on both sides with a drying medium, for example hot air for heat transfer. More specifically, the present invention provides a method for drying a fibrous web in a drying device wherein the fibrous web is guided in an open draw without being supported by clothing, with multiple redirection through the drying device through a plurality of drying spaces which are arranged parallel to each other and represent web guiding path sections. The web is treated on both sides with a drying medium, for example hot air for heat transfer. The fibrous web is guided through the drying device alternately in a vertical direction and opposite to the direction of gravity, and vice versa. Guidance of the fibrous web through the drying device occurs therefore alternately unsupported by clothing from the bottom up and from the top down, or vice versa.

The fibrous web is guided over guiding devices, such as turn rollers, for example through a plurality of drying spaces arranged parallel to each other and extending in a width direction of the drying device and in a vertical direction, and at the transition between two adjacent drying spaces. The individual drying space is hereby defined by blower devices arranged on both sides of the web guidance path and each representing one blower unit.

The vertical direction is consistent with the direction extending substantially perpendicular to a horizontal reference plane. Substantially in the vertical direction means that also deviations, that is variances in the range of approximately ±20° of the web path from the vertical direction are still possible and are included in this term. The horizontal reference plane may, for example, be described by a floor, machine floor or a base.

A web guidance path segment is to be understood to be the web path segment theoretically characterized by the guidance of the fibrous web. The individual vertically aligned web guidance path segment intended for guidance of the fibrous web is defined by the arrangement of the individual turn rollers which are allocated to the respective drying space for transferring into/transferring out of the respective adjacent drying space.

The vertical guidance of the fibrous web offers the advantage that the fibrous web, in the event of a breakdown or web break, can be removed from the individual drying space quickly and at the lowest possible expense, in particular since it can continue to run in the direction of gravity in catch- and/or processing devices located below the individual drying spaces.

Due to the multiple returns, very long web guidance paths are realizable in the drying device. The individual web guidance path segments extending in the vertical direction can be realized by utilizing the overall height that is theoretically available for the drying device, thereby being able to provide high drying efficiencies in a machine direction, in other words viewed in a longitudinal direction of the drying device within a minimal construction space.

The solution according to the present invention moreover offers the advantage of a simple and targeted treatment of the fibrous web with drying medium, since this is no longer required for stabilizing the fibrous web when guiding it through the drying device, but has only to assume the task of the heat transfer.

By eliminating the dual function of the drying medium, the individual blower devices can be arranged at small distances from the web guidance path segment and thereby from the fibrous web, thereby improving efficiency. Higher flow velocities and thereby higher drying rates are possible.

The dry content of the fibrous web at the infeed to the drying device is thereby at least approximately 45%, for example 50%.

In accordance with one arrangement of the device according to the present invention, the individual sides of the fibrous web, at least in a region of a web guidance path segment inside an individual drying space are treated equally with drying medium. This means that the fibrous web in this web guidance path segment is treated equally on both fibrous web sides. The individual operating parameters of the blower devices which are arranged on both sides of the fibrous web and state variables of the drying medium emerging from the blower devices are equal in this region. This improves the uniformity of the fibrous web.

In order to influence the dry profile of the fibrous web, the individual fibrous web sides, at least in one region of a web guidance path segment inside an individual drying space, can also be treated differently with drying medium. This option allows possibly for example upstream one-sided or different two-sided treatment of the fibrous web prior to running into the drying device.

In accordance with one embodiment of the present invention, treatment of one fibrous web side can be profiled in an individual drying space in a width direction of the drying device and/or over the entire extension of the drying space in a vertical direction, and can be controlled and/or regulated incrementally or infinitely, for example in one or in a plurality of zones. The advantage exists in the possible profiling of the drying efficiency and thereby the drying rate in the different directions of the fibrous web and thereby in the ability to influence the characteristics of the fibrous web which are subject to drying. This allows uniform drying over the entire fibrous web width while avoiding excessive drying of the edge regions. Moreover, changing edge conditions can be can be locally targeted in a timely fashion. The present invention, by its configuration, permits optimization of the drying process in all regions of an individual web guidance path segment.

A uniform treatment of a fibrous web side in an individual drying space in the width direction and over the entire extension of the drying space in the vertical direction is also conceivable.

Profiling occurs depending on at least one of the following parameters defining the operational mode and/or geometry of an individual blower device and/or state variable of the drying medium and/or parameters of the fibrous web:

• • a variable characterizing the geometry of the discharge opening from the blower device;
  • discharge angle of the drying medium+45°;
  • flow speed of the drying medium, for example 5 meters per second (m/sec) to 60 msec;
  • volume flow of the drying medium, for example 3 cubic meters per minute per blower device (m³/min/m/blower device) to 20 m³/min/m/blower device;
  • distance of the blower device to the fibrous web, for example 5 millimeters (mm) to 50 mm;
  • state variables of the drying medium (temperature, pressure), for example a temperature in the range between approximately 100° C. and 350° C. and/or a pressure between approximately 400 Pascal (pcal) to 2000 pcal;
  • throughput per time unit; and
  • speed of fibrous web, for example 50 meters per minute (m/min) to 350 m/min.

In order to avoid fibrous web breaks an additional arrangement of the present invention provides that a plurality of drying spaces which are arranged parallel to each other and extend in a cross direction and a vertical direction of the drying device, the turn rollers coupling them and thereby the web guidance path segments defined by them are combined into a group. Several groups, however at least two, may be provided in a drying device. The individual groups are arranged and formed such that the extension of the web guidance path segments progressing through the individual drying spaces viewed in the vertical direction from an infeed into the drying device to the outfeed from the drying device increases in size from group to group. In consideration of the formation and the operating parameters of the drying device, the group having the maximum extension is arranged such that it is reached only when a predetermined minimum dry-content of the fibrous web is achieved. This is the dry content which is necessary to be able to let the fibrous web hang freely over the maximum span of the web guidance path, without it tearing. The dry content of the fibrous web in the region of the infeed into the drying device is, for example between 45% and 50%, and on the outfeed side approximately 90%, whereby at least one drying curve is provided between the two.

An additional arrangement of the present invention provides that always a plurality of drying spaces which are arranged parallel to each other and extend in the cross direction and the vertical direction of the drying device, and the turn rollers coupling them are combined into a group, whereby the individual groups are arranged and formed such that the speed of the fibrous web in the individual groups can be controlled separately. This offers the advantage of an individual adjustment of the tension of the fibrous web and thereby the stress upon it.

Advantageously the supply of the individual blower devices occurs through a drying medium supply system which is allocated to at least one individual blower device and can be connected with same. According to a further embodiment of the present invention, the moist drying medium which is present after the drying process in the individual drying space is processed and is again supplied as drying medium via the blower devices to the drying space. For this purpose, the drying medium which is to be supplied to a drying space and the drying medium enriched with moisture from the drying space is led between two adjacent blower devices of one or different blower units in a loop with optional in-line warming—or for example, heating devices. This is realized through recirculating blowers which are arranged on both sides of a blower unit and which are connected with the suction side with the dryer space and with the pressure side with a blower device. Separate suction devices in the region of the individual drying space can thereby be eliminated.

In order to improve access to the drying spaces for the purpose of maintenance and cleaning, the width of the individual drying space is variably adjustable in the machine direction. In the event of a web break the fibrous web can thereby be quickly and securely guided into catch—and processing devices which are arranged below the drying device.

In order to ensure a safe web removal in the event of a web break or other malfunction, the fibrous web is severed consecutively or simultaneously between the individual web guidance path segments in the individual drying spaces. The separation occurs, for example in the return region between to drying spaces which are arranged following each other in the direction of web travel.

According to the present invention, the drying device for drying a fibrous web, including blower devices arranged on both sides of the theoretical web guidance path for the application of drying medium onto the fibrous web which is guided in the drying space formed by them further provides the individual blower devices are arranged extending in the cross direction of the drying device and extending in the vertical direction. The drying spaces progressing in the vertical direction are limited. A plurality of drying spaces progressing in the vertical direction are arranged adjacent to each other to accommodate web guidance path segments in the machine direction and above and below an individual drying space, turn rollers are provided for transferring the fibrous web between two adjacent drying spaces. Two turn rollers allocated to a drying space for connection with the adjacent drying space define web guidance path segments. The drying device is free of a fibrous web supporting clothing.

The repeated reversal allows very long web guidance paths inside the drying device. The thereby formed individual web guidance path extending in the vertical direction can be realized by utilizing the overall height that is theoretically available for the drying device, thereby realizing the high efficiencies in the machine direction, in other words viewed in the longitudinal direction of the drying device within a minimal construction space. Apart from the redirection, the fibrous web is guided essentially only in the vertical direction and is stabilized through gravitational force. This allows for a targeted local and timely treatment of the fibrous web with drying medium, since this is its main function and only needs to serve to heat the fibrous web and is not required for formation of stabilizing air cushions. By eliminating the dual function of the drying medium, the individual blower devices can be arranged at small distances from the web guidance path segment and thereby from the fibrous web, thereby improving efficiency.

In accordance with one embodiment of the present invention the individual blower devices which are always arranged on both sides of an individual web guidance path segment represent one blower unit. The individual blower device can be arranged to be subdivided into blower zones in the cross direction and/or in the vertical direction of the drying device, whereby a device or controller for individual and/or joint control of the individual zones is provided.

The individual blower device includes, for example, a plurality of blow boxes arranged in the vertical direction in blower towers which are arranged extending in the cross direction of the drying device and which are supported on a frame.

A drying medium supply system is allocated to the individual blower device alone or to several together which, in the simplest case, includes a drying medium supply unit coupled with the blower device. In one arrangement according to the present invention, viewed in the cross direction of the drying device, recirculating blowers are arranged on both sides of the individual blower unit, whose suction sides are connected with the drying space and pressure sides with a blower device of the blower unit, forming a circulation system, whereby upstream from the connection of the pressure side with the blower device a heating device for heating of the drying medium which is to be brought into the blower device can be located. In a further development, the recirculating blowers allocated to a blower device are advantageously arranged in the vertical direction one above the other and supported in a blower tower. This can be constructed separately or as a component of the frame. The blower tower can be constructed so that it can be moved away from the drying device.

In an additional embodiment of the present invention, the drying medium supply system includes at least one fresh air supply and at least one exhaust air removal which can be connected with one and/or a plurality of loops. Fresh air supply and exhaust air removal have no fluidic connection with each other, but can however be optionally coupled thermally in an advantageous manner, for example through a heat exchanger. The heat of the exhaust air can thereby be purposefully and effectively used for heating the supply air to the blower devices.

To ensure a secure operation, a plurality of drying spaces arranged parallel to each other and extending in the cross direction and in the vertical direction of the drying device and the turn rollers connecting them with each other form a group. At least two groups are provided inside the drying device. The individual groups are arranged and formed such that the extension of the web guidance path segments progressing through the individual drying spaces viewed in the vertical direction from an infeed into the drying device to the outfeed from the drying device increases in size from group to group.

In an alternative or additional embodiment of the present invention, a device or controller for controlling the speed of the fibrous web, for example the rotational speed of the turn rollers is allocated to at least one individual group for adjusting the web tension.

To improve removal of fibrous web residues after a web break and for the purpose of cleaning, an apparatus or device for adjusting the width of at least one single drying space in the machine direction is provided. This device can include a mechanism for sliding and/or pivoting or a combination of both movements of the blower device. In one arrangement of the present invention, the device includes rotatable mounting units for two adjacently located blower devices of different blower units. The individual mounting unit includes a rocker arm rotatably mounted on the frame of the drying device on opposite ends of which the blower devices are flexibly hinged. Pivoting occurs through engagement of an adjusting device on a force application surface on the rocker arm. In accordance with one embodiment of the present invention, the activation of a plurality of mounting units can occur forcibly coupled.

In a further embodiment of the present invention, at least one knock-off device is provided which—in the event of malfunctions—severs the fibrous web in the region between two drying spaces, as a result of which the remainder of the fibrous web falls in the direction of gravity. If several knock-off devices are provided, these can become effective simultaneously or consecutively between two drying spaces.

The arrangement of the effective region of individual knock-off devices can occur according to one of the following options:

• • in the vertical direction in the region of the upper turn devices;
  • in the vertical direction in the region of the lower turn devices; or
  • inside the drying spaces, for example in the vertical direction between upper and lower turn devices.

The individual knock-off device can be configured or arranged so that its effective region is such that it extends at least over a section of the drying device in the cross machine direction or is movable, whereby this section can be constantly predetermined or adjustable. In this case, the fibrous web is only partially severed, whereby the remaining fibrous web due to the weight of it tears in the gravitational direction.

In one embodiment of the present invention, the individual knock-off device is configured or can be arranged so that its effective region is such that it extends at least over the extension of the fibrous web in the cross machine direction, for example the extension of the drying device in the cross machine direction.

Regarding the configuration and mounting of the individual knock-off device, there are a multitude of options. The individual knock-off device includes at least one knock-off element which is mounted on a stationary or movable support. In the latter instance, the support can be movable, for example sliding in the vertical direction and/or the machine direction and/or the cross machine direction. Moreover, in addition or alternatively to the aforementioned option, the support can be pivoted. Mounting on the support depends on the selection of the type of knock-off element and the form of the movability of the support. In the case of a movable support, the knock-off element may also be mounted stationary on it.

On a stationary or movable support the individual knock-off element can be mounted on it movably in the cross machine direction, and in contrast to this possibly also pivoted.

The inventive solution is suitable, for example for drying of fibrous webs consisting of cellulose fibers.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematically simplified illustration which clarifies the basic configuration and basic function of a drying device according to the present invention;

FIG. 2 is detail of a section from a web guidance path segment according to the device of FIG. 1;

FIGS. 3A to 3F illustrate different modification options for an individual blowing device in the device according to the present invention;

FIG. 4 is an exemplary illustration of fibrous web guidance in a drying device with group sectioning according to the present invention;

FIG. 5 is an exemplary illustration of drying medium guidance for individual blower units in the device according to the present invention;

FIG. 6 is a schematically simplified perspective illustration of a blower tower of the device according to the present invention;

FIG. 7 illustrates the fresh air supply and exhaust air removal in the device according to the present invention;

FIG. 8 illustrates a possible configuration of a frame for a drying device according to the present invention;

FIG. 9 is an exemplary illustration of a possible configuration of a platform component of the frame of the device according to the present invention;

FIGS. 10A to 10C illustrate an inventive option for variable adjustment of the width of the drying space between two blower devices of a blower unit of the device according to the present invention;

FIG. 11 illustrates a possible arrangement of grating of the device according to the present invention;

FIG. 12 illustrates an embodiment of an inventive drying device with additional knock-off device; and

FIGS. 13A to 13E illustrate possible function positions of the knock-off devices of the device according to the present invention.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate one embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIG. 1, there is schematically illustrated, in a greatly simplified depiction, the basic configuration and basic function of a drying device 1 according to the present invention. For visualization of individual directional statements a coordination system has been established. X-direction is consistent with the direction of travel of fibrous web F through drying device 1. This is consistent with the longitudinal direction of drying device 1 and is therefore also identified as machine direction MD. Y-direction describes the direction perpendicular to machine direction MD, that is width direction of device 1 and is identified as cross machine direction CD. Z-direction is the height direction, that is the extension in the vertical direction.

According to the present invention, drying device 1 is a vertical drying device according to the impingement principle. Fibrous web F is guided through drying device 1 in an open web draw and with several redirections, in other words repeated directional changes, between an infeed 4 into drying device 1 and an outfeed 5 from drying device 1, essentially only in the vertical direction. Deviations of +20° from the vertical direction are possible. Drying device 1 is in the embodiment of a blower device, or respectively air drying device. Along its web guidance path, fibrous web F is treated on both sides with drying medium, for example with hot air. In contrast to the horizontal air drying devices known from the current state of the art, the hot air acting upon fibrous web F in the inventive solution, serves primarily only to transfer heat to fibrous web F and due to the vertical guidance of fibrous web F is not necessary for stabilization of the guidance of fibrous web F.

The application of the drying medium occurs by blower devices 2.na and 2.nb with n≧1 which are arranged on both sides of fibrous web F along the web guidance path, at a distance to same and thereby effective on different fibrous web sides. Blower devices 2.na and 2.nb which are arranged on both sides of fibrous web F along a web guidance path segment form a blower unit 2.n with n≧1. The individual blower devices 2.na and 2.nb, in this case 2.1a to 2.na and 2.1b to 2.nb are arranged in such a way that the blower devices 2.na, 2.nb of always one blower unit 2.n limit a drying space 3.n progressing in the vertical direction, with n≧1. Viewed in machine direction MD, blower units 2.1 to 2.n with blower devices 2.1 to 2.na and 2.1b to 2.nb limit here a plurality of drying spaces 3.1 to 3.n progressing in the vertical direction. These are arranged parallel to each other in machine direction MD and adjacent to each other. Guidance of fibrous web F occurs herein in the vertical direction—in other words from top to bottom or vice versa. Drying spaces 3.1 to 3.n accommodate hereby the vertically progressing web guidance path segments. The web guidance between two adjacent drying spaces 3.n-1 and 3.n occurs through turn rollers 6, 7.

The web guidance path of fibrous web F thereby includes a plurality of web guidance path segments, arranged parallel to each other and progressing in the vertical direction which are coupled together via turn rollers 6 and 7 and are arranged inside drying spaces 3.n.

Referring now to FIG. 2, there is shown an exemplary illustration of a segment from the web guidance path in drying space 3.1 formed by blower unit 2.1 for fibrous web F which is to be dried in drying device 1 according to FIG. 1. Individual blower devices 2.1a and 2.1b are arranged on both sides of the web guidance path of fibrous web F which is guided in the vertical direction and at a distance to same and thereby in the case of fibrous web F at a distance from it. Blower devices 2.1a, 2.1b act at least indirectly upon the surface of fibrous web F for the purpose of drying. Illustrated is the operational mode with uniform treatment of both sides of fibrous web F with hot air. Its discharge from individual blower devices 2.1a and 2.1b and impingement upon the respective fibrous web side is clarified by means of arrows. The individual jet thereby has at least one discharge angle α from the respective blower device 2.1a, 2.1b and an angle of impingement β onto the surface of fibrous web F. Impingement of the hot air occurs, for example, perpendicular to fibrous web F. In the respective impingement region the treatment of fibrous web F can thereby be influenced and actively controlled and/or regulated as a function of at least one of the following state variables characterizing the geometry and/or operational mode of blower device 2.1a, 2.1b:

• • discharge angle from the blower device;
  • impingement angle onto the fibrous web; and
  • discharge width of the discharge opening from the blower unit.

Moreover, treatment of fibrous web F with drying medium can be adjusted as a function of the state variable of the drying medium (temperature, pressure),—discharge speed and/or volume flow of drying medium from the blower device and/or the values characterizing at least indirectly the operational mode of drying device 1, for example traveling speed of fibrous web F.

For adjustment, for example control and/or regulating, a control device 8 is provided. Depending on predefined set points for the drying efficiency that is to be achieved or values characterizing same at least indirectly, individual blower devices 2.1a, 2.1b to 2.na, 2.nb are controlled. This is clarified in an example through coupling of the outputs of controller 8 with the control devices of blower devices 2.1a, 2.1b by issuing the hereby necessary manipulated variables Y2.1a and Y2.1b for blower devices 2.1a, 2.1b.

FIG. 2 illustrates an arrangement with uniform treatment on both sides of fibrous web 2 in the web guidance direction however, other possibilities are also conceivable which can be used by themselves or in combination with each other. Such additional developments are illustrated in FIGS. 3A to 3D.

In contrast to FIG. 2, FIG. 3 illustrates a possibility of the different treatment of the individual sides of fibrous web F with drying medium which is indicated by arrows of different sizes. For example, the drying mediums applied to opposite sides of the fibrous web can be characterized by different state variables, for example different temperatures.

Moreover there is the possibility alternatively or in addition of profiling of the drying medium over a desired application region on fibrous web F. Such possibilities are shown in FIGS. 3B to 3D. In all these possibilities the profiling can occur as a function of characterizing parameters of the geometry and/or the operational mode of blower device 2.1a, 2.1b and/or the speed of the fibrous web. The profiling can occur in the direction of web travel and/or transversely to it.

FIG. 3B illustrates an example for blower device 2.1a, showing the possibility of profiling of the drying medium in the direction of travel of fibrous web F through drying device 1, in particular over a web guidance path segment in drying space 3.1. Differently sized arrows shown the change in the drying medium profile in the direction of travel of fibrous web F inside drying space 3.1

FIG. 3C is a schematically simplified illustration showing the possible arrangement of blower device 2.1 with blower zones sectioned in the vertical direction. The individual zones are for example identified with BZ1 to BZn. These can be realized in one single blower device 2.1a by subdividing a common interior space into individual partial spaces, or by arranging blower device 2.1a with individual separate blower devices, for example blow boxes. A desired dry medium distribution having the desired characteristics can be achieved over the web guidance path segment in dryer space 3.1 through the individual and/or group control of the individual zones.

In a section from a view onto blower device 2.1a in the CD/z-plane, FIG. 3D illustrates an additional development of one arrangement from FIG. 3C, whereby blower zones are divided in addition also in the width direction of drying device 1. The individual zones are identified, for example, with BZ1.1 to BZ1.n to BZn.1 to BZn.n with n>1. These can be realized in one single blower device 2.1a by subdividing a common interior space into individual partial spaces and/or by arranging blower device 2.1a with individual separate blower devices, for example blow boxes. A desired drying medium distribution having the desired characteristics can be achieved over the web guidance path segment in dryer space 3.1 and moreover in cross machine direction CD—that is the width direction—through the individual and/or group control of the individual zones. The arrangement of individual blower device 2.1 is also conceivable consisting of a plurality of blowers that are arranged one above the other in the vertical direction and extending at least over the width of fibrous web F which is to be conditioned in drying device 1, whereby the individual blowers describe blower zones in the vertical direction and are moreover sectioned/divided into zones in the cross machine direction. Control of individual zones BZ1.1 to BZn.n occurs in this case also individually, in groups or together.

The size of the zone can be constant or can vary in cross machine direction CD and/or in vertical direction.

In all embodiments of the present invention, the treatment of fibrous web F with drying medium can occur selectively, linearly or over an area. An area treatment covering the entirety of the fibrous web is strived for. The drying medium can hereby be applied by blower device 2.1a through a plurality of individual nozzles 9.1 to 9.n having a round cross section as shown in FIG. 3E in an exemplary view of a section from blower device 2.1a. Use of other cross sectional geometries is also conceivable, such as slotted nozzles 10.1 to 10.n extending at least over a partial region of the extension of blower device 2.1a in cross machine direction CD, as illustrated in FIG. 3F in an exemplary view onto a section of a blower device 2.1a.

A further development of the present invention provides that inside individual drying spaces 3.1 and 3.n, grating is to be provided on the blower devices in front of the outlet openings for the drying medium to protect them from contamination from fibrous web F in the event of a web break.

Referring now to FIG. 4, there is shown a greatly simplified schematic illustration of a view in the machine direction MD/z-plane onto drying device 1, clarifying an exemplary possible guidance of fibrous web F, without illustration of the blower devices. Fibrous web F is illustrated here in broken lines. It is brought into drying device 1 in infeed region 4. In the illustrated example, infeed region 4 is arranged in the vertical direction in the upper region of drying device 1. Through the individual turn rollers 6, 7 which are arranged in the vertical direction in rows offset to one another, fibrous web F experiences a corresponding directional change and redirection in guidance in the vertical direction through drying device 1 through to outfeed 5 which is arranged, for example in the vertical direction, in the lower region of drying device 1. It can be seen here that fibrous web F experiences a multitude of directional changes and, viewed in machine direction MD is thereby guided in the most confined space over a plurality of parallel web guidance path segments. Due to this, the dwell time inside drying device 1 can be considerably increased. FIG. 4 does not illustrate individual blower devices 2.1a, 2.1b to 2.na, 2.nb which are arranged on both sides of the web guidance path resulting from the guidance of fibrous web F and which form or respectively limit drying spaces 3.1 to 3.n.

It can be seen that fibrous web F is not immediately guided in the vertical direction through drying device 1 utilizing the maximum possible height of same. The web guidance path segments following infeed region 4 are characterized by a smaller extension in the vertical direction and thereby height than the following web guidance path segments. This is recognized on the different vertical offset of turn rollers 6 and 7 which characterize a web guidance segment and which are arranged above and below the individual drying space. Upper turn rollers 6 are thereby arranged in the vertical direction at one level and at a distance from each other in machine direction MD, whereas lower turn rollers 7 are arranged at different height levels.

A plurality of drying spaces which are arranged parallel to each other and extend in cross machine direction CD and in the vertical direction, and associated turn rollers 6, 7 and the thereby defined web guidance path segments are combined into groups, in this case I to VI. Inside individual groups I to VI the drying spaces or individual web guidance path segments are, for example, arranged with constant extension in the vertical direction. The height of the individual drying spaces or respectively the extension of the web guidance path segments progressing through them increases from group to group. Fibrous web F is thereby guided over the maximum extension of drying device 1 in the vertical direction in group V only from the time when fibrous web F reaches a predefined dry content. The entire available space, originating from floor 11 is thereby, for example used.

Infeed 4 into drying device 1 can be implemented through an automatic transfer system, for example through a rope transfer.

In the region of outfeed 5 from drying device 1a cooling region 26 may be provided. Here, fibrous web F is treated only with ambient air which is, for example, supplied via non-illustrated centrifugal blowers to the also non-illustrated blower devices which are arranged along the respective web guidance path segment on both sides of fibrous web F. Cooling region 26 includes here group VI.

To supply individual blower devices 2.1a to 2.na, 2.nb with the necessary hot air, drying medium supply system 12 is provided. This includes blowers which supply blower devices 2.1a, 2.1b to 2.na, 2.nb with the required drying medium at the required process parameters. These are functionally coupled with the associated blower devices.

In order to ensure smooth operation it is moreover necessary to also remove the moist air from individual drying spaces 3.1 to 3.n. Blowers are also used for this. Recirculation blowers may be used which, in addition to removal of the moist drying medium, for example moist air, also serve to blow in heated drying medium, such as air as the drying medium.

FIG. 5 clarifies in a schematically simplified illustration an embodiment of the drying medium guidance in a view onto the MD/CD plane, as a component of drying medium supply system 12. The drying medium is guided inside one, or through blower units 2.1 to 2.n, overlapping in loops K which are a component of drying medium supply system 12. Individual loop K is free of fresh air supply. This means that the air which is present in the system is guided in respective loop K and in the forward flow serves to transport heat to fibrous web F. In the return flow the exhaust air is heated in order to bring it to a predefined temperature before it is again supplied to blower units 2.1 to 2.n. Recognizable are recirculation blowers 13 which are arranged on both sides in cross machine direction CD of blower devices 2.1a to 2.2b of blower units 2.1 to 2.2 and which serve to remove moist air from drying spaces 3.1 to 3.n and to supply dry air as the drying medium to blower devices 2.1a to 2.3b. The air flow is thereby guided in cross machine direction CD. After, for example, hot air heat is transferred from the drying medium to fibrous web F by at least partial evaporation the moist airflow emerges from the respective drying space 3.1 to 3.n. The drying medium is hereby, for example guided in a loop between individual blower devices 2.1a, 2.1b, 2.2a, 2.2b, whereby after exiting from these the air is guided over heating device 14 and is supplied again by recirculating blower 13 to the blower devices located adjacent to one another in machine direction MD of the same or adjacent blower units 2.1 to 2.n. Here too, after exiting from this respective blower device a recirculation occurs to the blower device located upstream or downstream in the machine direction of the same or adjacent blower units. The individual recirculating blowers 13 required for this, as well as heating devices 14 located before the infeed into blower devices 2.1a to 2.3b are thereby always arranged on both sides of blower units 2.1, 2.2 in so-called blower towers 27 as indicated for example in FIG. 6. Depending on the extension of an individual blower device which is a blow box in the vertical direction at least one recirculating housing is allocated to same. One or several recirculation blowers 13 can thereby by allocated to one blow box, or one recirculation blower 13 can be allocated to several blow boxes which are arranged one above the other. Individual recirculation blowers 13 are equipped with frequency converters for control of the operational mode. Each individual blower tower 27 is thereby allocated to one side of drying device 1 in cross machine direction CD that is in the width direction of the web and has a fluidic connection with respective blower devices 2.1 to 2.n. Blower towers 27 include the supports for blowers 13 and always form one unit which can be moved away from drying device 1 if required. Individual recirculating blowers 13 and heating devices 14 located downstream from them may be arranged so that easy accessibility is provided. They may be arranged in different levels and are accessible to maintenance and inspection personnel in each level through inspection doors 19. The blower devices are also arranged as blower devices 2.1a to 2.n extending in the vertical direction always over the height of one level and in cross machine direction CD extending over same. The level-type arrangement is especially advantageous. Other configurations are however also conceivable. However, at least one or several recirculating blowers or recirculating motors 13 should be accessible on each level.

The supply of fresh air through drying medium supply system 12 is illustrated in a schematically simplified depiction with a view onto CD/Z plane of drying device 1 in FIG. 7. Whereas loops K are guided in cross machine direction CD, the fresh air supply occurs in respect to the flow direction at an angle, in this case perpendicular to air guidance in loops K. FIG. 7 shows exhaust removal 28 and fresh air supply 29. There is no fluidic connection between them, meaning that there is no intermixture of exhaust air AL and supply air ZL, or respectively fresh air. Exhaust air AL is removed in the vertical direction on top from the individual blower units 2.1 to 2.n, in other words from above the last blower device, for example the last row of blow boxes in an individual blower unit 2.1 to 2.n, whereas supply air ZL is supplied from below to individual blower units 2.1 to 2.n in the vertical direction to the lower rows of blow boxes. The supply occurs hereby on both sides of drying device 1, for example through blower towers 27.

For this purpose they are equipped with at least one supply opening in the lower region, for example on the floor of the first level, and with at least one discharge opening in the vertical direction in the upper region, for example an upper corner or a side wall of the upper level of blower tower 27. Exhaust air removal 28 and fresh air supply 29 are however coupled energetically, for example thermally in order to utilize the heat contained in the exhaust air AL to preheat supply air ZL. The coupling occurs, for example, through at least one heat exchanger 30 which can be in different embodiments and through which the two mediums are guided in parallel flow or counter flow. In the simplest case, exhaust air AL is guided around a wall section in the path for supply air ZL.

Constructively, individual turn rollers 6, 7 and blower devices 2.1a, 2.1b to 2.na, 2.nb of individual blower units 2.1 to 2.n and/or recirculating blowers 13 and heating devices 14 or respectively blower towers 27 respectively are supported on frame 15, an example of which is illustrated in FIG. 8. As already explained, individual blower devices 2.1a to 2.nb are always arranged in blower towers in which in the vertical direction blow boxes extending across the machine width are arranged one on top of another. Frame 15 forms a support structure for them consisting of support members. The support structure defines spaces 16 arranged parallel to each other in machine direction MD and extending in the vertical direction, to accommodate individual blower units 2.1 to 2.n. Platforms are located on both sides of spaces 16 in cross machine direction CD to ensure accessibility to the drying spaces. The individual platforms on the operating and drive side of drying device 1 are always combined in one platform component 17 and are anchored in the basic structure of the frame. To protect operating personnel and to ensure accessibility to blower devices 2.1a to 2.nb, as well as to drying spaces 3.1 to 3.n for the purpose of cleaning and inspection, respective platform component 17 is equipped with appropriate panels 18 and shutters or door parts 19 as illustrated in FIG. 9. Recirculating blowers 13 and heating devices 14 can thereby be mounted directly in frame 15.

In this case, individual blower tower 27 consists of these and frame components of frame 15. The support structure for recirculating blower 13 and heating device 14 is however, for example, provided by a separate frame component 31, as illustrated in FIG. 6, which is connected or respectively can be combined to a detachable constructional unit with frame 15.

FIGS. 10A to 10C illustrate an embodiment of drying device 1 with possibility of at least a temporary enlargement of individual drying spaces 3.1 to 3.n. Individual blower devices 2.1a, 2.1b to 2.na, 2.nb are supported in frame 15 in a manner that drying space 3.1 to 3.n formed between them can be varied in regard to its extension in machine direction MD. This is achieved through mounting unit 20. This includes a rocker arm 21 which is rotatably mounted on frame 15 by a swivel joint 22 on which two blower devices which are located adjacent to each other from one or from two different blower units are flexibly hinged respectively at a distance (a) from the pivot point. Distance (a) from the pivot point is, for example, selected to be the same for both blower devices. In an arrangement of the present invention, the adjacently located blower devices of different blower units 2.1 to 2.n are mounted on rocker arm 21. In FIG. 10A blower devices 2.1b and 2.2a, 2.2b and 2.3b, 2.3b and 2.4a, 2.4b and 2.na respectively are flexibly hinged on rocker arm 21 at a distance to its pivot point. Mounting can occur depending on the configuration of rocker arm 21 with an additional offset in the vertical direction to the pivot point, or free of this. In the first case which is illustrated in an enlargement in FIG. 10B, rocker arm 21 is triangular or trapezoid. To operate it, a force application surface 25 is provided on which for example a cylinder-/piston unit acts for the purpose of displacement/rocking. The rocking motion then leads to a superimposed horizontal and vertical movement in opposite direction of blower devices 2.1b and 2.2a, 2.2b and 2.3a, 2.3b and 2.4a and 2.na of two adjacently arranged blower units 2.1 to 2.n which are mounted through joints 23, 24 on rocker arm 21, thus leading to a reduction in the distance to each other, whereby drying spaces 3.1 to 3.n on the other side are enlarged.

The configuration of mounting unit 20 is shown exemplary in detail in FIG. 10B.

FIG. 10A illustrates drying device 1 under normal operational condition without enlargement of drying spaces 3.1 to 3.n. FIG. 10C in contrast illustrates drying device 1 with enlarged drying spaces 3.1 to 3.n due to tilting of individual blower devices 2.1b and 2.2a, 2.2b and 2.3a, 2.3b and 2.4a, 2.4b and 2.na and thereby the blower towers for the purpose of carrying out cleaning procedures. One can see here the movement of the respective one blower tower upward in the vertical direction and the movement coupled with this due to the connection through rocker arm 21 of the adjacent connected blower tower downward, thus reducing the distance to each other, thereby increasing the respectively adjacent drying space. The movement may be controlled to occur individually or in groups. The movement can be realized mechanically, hydraulically, electrically, electronically or through a combination thereof. The movement of all blower devices 2.1b and 2.2a, 2.2b and 2.3a, 2.3b and 2.4a, 2.4b and 2.na may occur forcibly coupled together.

In contrast to the configuration in FIG. 10A, FIG. 10C illustrates drying device 1 in the cleaning position with enlarged drying spaces 3.1 to 3.n due to superimposed vertical and horizontal movement of individual blower devices 2.1 to 2.nb due to tilting. The movement of blower device 2.nb of blower unit 2.n in the vertical direction downward is recognizable, and the movement coupled thereto of connected blower device 2.n+1a of the respectively adjacent blower unit 2.n+1 upward. The movement may be controlled to occur individually or in groups. The movement can be realized mechanically, hydraulically, electrically, electronically or through a combination thereof.

According to the embodiment of the present invention shown in FIG. 10C all blower units 2.1 to 2.n may be mounted so that they are operated together, that is simultaneously and forcibly coupled.

According to an advantageous further development grating 35.1a-35.nb is provided inside individual drying spaces 3.1 and 3.n. In the example these are shown in FIG. 11 for blower units 2.1 to 2.n which are supported on frame 15 by mounting units 20. In the simplest case these are thin metal plates with openings through which drying medium is removed after contact with fibrous web F and is recirculated in loop K through the recirculating blower which is installed downstream in the flow path.

Referring now to FIG. 12, there is shown a schematically greatly simplified illustration of a section from drying device 1 with at least one additional device in the embodiment of a knock-off device, in this case two knock-off devices 32.1 and 32.2 to sever fibrous web F in the event of a web break. Knock-off device 32.1, 32.2 can be configured in different ways. Individual knock-off device 32.1, 32.2 is mounted for example on frame 15 and includes a support 33.1, 33.2 which is equipped with knock-off elements, for example knock-off blades 34.1, 34.2. Individual knock-off devices 32.1, 32.2 are mounted movably, for example sliding relative to turning devices 6 and become effective on fibrous web F in this region. Individual knock-off device 32.1, 32.2 is configured such that it can be arranged suitably for knocking-off or severing fibrous web F, at least over a partial region of the extension in the cross machine direction, for example over the entire extension in cross machine direction CD.

The knock-off elements, for example knock-off blades 34.1, 34.2 are for example mounted on support 33.1, 33.2 which extends for example in cross machine direction CD and are movable in this direction at least over a partial section of the support. Moreover, the mounting may be movable relative to support 33.1, 33.2 perpendicular to the direction of extension in the cross machine direction, or pivoted.

An alternative arrangement which is not illustrated here consists in the appropriate movability of support 33.1, 33.2 in the cross machine direction.

Severing of fibrous web F occurs in the upper region of the drying device, in particular in the region of upper turn rollers 6. In FIG. 12 drying device 1 is illustrated in the operating position or also during tagout. Knock-off devices 32.1 and 32.2 are in their operating position I. In the illustrated example this operating position I which is consistent with a position outside a knock-off position is characterized by a positioning or respectively mounting of knock-off devices 32.1, 32.2 before or after turn rollers 6, when viewed in machine direction MD. To bring them into a knock-off position, knock-off devices 32.1, 32.2 are moved individually or together into the desired knock-off position. The movement of the individual knock-off devices 32.1, 32.2 can hereby be controlled separately or both are coupled, whereby the movements occur consecutively or simultaneously. The movement occurs dependent on the starting position of knock-off devices 32.1, 32.2—in the illustrated case for example through a movement of the support 33.1, 33.2 in machine direction MD or in the vertical direction. Also conceivable is the arrangement which is not illustrated, with positioning of knock-off devices 32.1, 32.2 in operating position FI only in the vertical direction with offset to the actual knock-off position. Knock-off elements 34.1, 34.2 are then brought into the knock-off position through appropriate positioning and movability relative to support 33.1, 33.2, and are moved in the cross machine direction, either through movement of the support or through movement relative to the support when positioning the support in a stationary position.

FIGS. 13A to 13E illustrate possible positions of knock-off devices 32.1 to 32.2 in different operating modes. FIG. 13A illustrates drying device 1, whereby blower devices 2.1 to 2.nb are arranged in the cleaning position. These and in particular also the blower towers formed by them are deflected due to enlargement of drying spaces 3.1 to 3.n. In this operating mode, knock-off devices 32.1 and 32.2 are still in operating position FI.

FIG. 13B illustrates the movement of knock-off devices 32.1, 32.2 in the event of malfunction in operating position FI i. In this position they act upon fibrous web F in the region of the first two turn rollers 6. Fibrous web F falls downward in drying spaces 3.1, 3.2 and can be captured in a catch device and/or can be guided to a processing plant. Knock-off devices 32.1, 32.2 are moved into the desired knock-off position for this purpose opposite to turn rollers 6.

FIGS. 13C to 13E illustrate additional operating positions FIII-FV of knock-off devices 32.1, 32.2 which are characterized by the movement of the knock-off devices in machine direction MD, always to the next or the next but one turn roller 6, so that fibrous web F, in the event of a malfunction, is present in individual drying spaces 3.1 to 3.n consecutively as individual strips and in the spaces falls downward in gravitational direction. Knock-off device 32.1, 32.2 is thereby moved in drying device 1 so that it becomes effective always on the individual adjacent guidance regions. The severed web region is depicted with a thicker rippled line. The respective previous position of individual knock-off devices 32.1, 32.2 is indicated by broken line. Their movements are indicated by arrows.

FIG. 13C shows knock-off device 32.1 moved in machine direction MD behind knock-off device 32.2. This operating position of the two knock-off devices 32.1, 32.2 is identified with FIII. In operating position FIV knock-off device 32.2 is moved behind knock-off device 32.1 in machine direction MD. Operational position FV is characterized by the new offset of knock-off device 32.1 in machine direction MD behind knock-off device 32.2. It can be seen that knock-off occurs on consecutive web guidance path segments in the region of the turning devices. Actuation or respectively positioning of individual knock-off devices 32.1, 32.2 occurs alternately. Knock-off device 32.1 to 32.n can be arranged with rotating blades or water jet. The rotating blades or the water jet are arranged to be movable, for example, in the cross machine direction, or in particular can slide.

FIGS. 13A to 13E illustrate an arrangement of the knock-off device in an upper knock-off position. Also conceivable is an arrangement which is not illustrated here inside the drying spaces as well as also in the region in vertical direction of lower turn rollers 7.

While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Component identification list

• • 1 drying device
  • 2.1-2.n blower unit
  • 2.1a, 2.1b, 2.na, 2.nb blower device
  • 3.1-3.n dryer space
  • 4 infeed
  • 5 outfeed
  • 6 turn roller
  • 7 turn roller
  • 8 controller
  • 9.1-9.n nozzle
  • 10.1-10-n slotted nozzle
  • 11 floor
  • 12 supply system
  • 13 recirculating system
  • 14 heating device
  • 15 frame
  • 16 space
  • 17 platform component
  • 18 panels
  • 19 door
  • 20 mounting unit
  • 21 rocker arm
  • 22 swivel joint
  • 23 joint
  • 24 joint
  • 25 force application surface
  • 26 cooling region
  • 27 blower tower
  • 28 exhaust air removal
  • 29 fresh air supply
  • 30 heat exchanger
  • 31 frame component
  • 32.1, 32.2 knock-off device
  • 33.1, 33.2 support
  • 34.1, 34.2 knock-off element
  • 35.1a-35.nb grating
  • BZ1-BZn zone
  • BZn.1-BZn.n zone
  • F fibrous web
  • FI, FII, FIII, FIV, FV operating positions of knock-off devices
  • MD machine direction
  • CD cross machine direction
  • K loop
  • X, Y, Z coordinates
  • Y2.1a, Y2.1b set point
  • I, II, III, IV, V, VI group
  • ZL supply air
  • AL exhaust air
  • α discharge angle
  • β angle of impingement

Claims

1. A method for drying a fibrous web in a drying device, the method comprising the steps of:

arranging a plurality of drying spaces of the drying device parallel to each other, said plurality of drying spaces including a plurality of web guiding path sections;

guiding the fibrous web in an open draw with a plurality of redirections through the drying device through said plurality of drying spaces, the fibrous web being guided through the drying device alternately in a vertical direction with a deviation of up to and including ±20° from said vertical direction and opposite to a direction of gravity, and vice versa; and

treating the fibrous web on both sides with a drying medium.

2. The method according to claim 1, wherein said drying medium is hot air for a heat transfer.

3. The method according to claim 1, wherein said plurality of drying spaces extend in a cross direction of the drying device and are limited by a plurality of blower devices arranged on both sides of a web guidance path formed by said plurality of web guidance path sections defining a blower unit and at a transition between two adjacent said drying spaces the fibrous web is guided over a plurality of guiding devices.

4. The method according to claim 3, said guiding devices being a plurality of individual turn rollers, said individual vertically aligned web guidance path sections provided for said guidance of the fibrous web being defined by an arrangement of said plurality of individual turn rollers, said individual turn rollers being allocated to a drying space of said plurality of drying spaces for transfer into and transfer out of a respectively an adjacent drying space of said plurality of drying spaces.

5. The method according to claim 1, wherein in said treating step both sides of the fibrous web are treated equally with said drying medium, at least in a region of one of said web guidance path sections inside an individual of said plurality of drying spaces.

6. The method according to claim 1, wherein in said treating step both sides of the fibrous web are treated differently with said drying medium, at least in a region of one of said web guidance path segments inside an individual of said plurality of drying spaces.

7. The method according to claim 4, wherein in said step of treating the fibrous web includes the step of controlling said treatment one of incrementally and infinitely, said treatment being uniform in an individual of said plurality of drying spaces in a cross direction of the drying device and over an entire extension of a said individual of said plurality of drying spaces in said vertical direction or said treatment of the fibrous web is profiled in at least one of a width direction and said vertical direction.

8. The method according to claim 7, said step of controlling said treatment of the fibrous web is in at least one of a plurality of zones of one of said plurality of blower devices.

9. The method according to claim 8, further comprising the step of adjustably defining at least one of an operational mode, a geometry of said individual blower device, a state variable of said drying medium and a speed of the fibrous web using at least one parameter, said at least one parameter including at least one of:

a dimensional geometry of an individual discharge opening;

a discharge angle of said drying medium;

a distance of said individual blower device from the fibrous web;

a flow speed of said drying medium;

a volume flow of said drying medium;

a plurality of state variables of said drying medium, said plurality of state variables including temperature and pressure;

a throughput of said drying medium per time unit; and

a speed of the fibrous web.

10. The method according to claim 9, wherein said adjustably defining step includes controlling at least one of said operational mode, said geometry of said individual blower device, said state variable of said drying medium and said speed of the fibrous web.

11. The method according to claim 10, wherein said adjustably defining step includes regulating at least one of said operational mode, said geometry of said individual blower device, said state variable of said drying medium and said speed of the fibrous web.

12. The method according to claim 11, wherein always said plurality of drying spaces arranged parallel to each other and extending in said cross direction and said vertical direction of the drying device and said plurality of turn rollers coupling said plurality of drying spaces are combined into an individual group, a plurality of said individual groups being arranged and configured such that an extension of said web guidance path sections progressing through said plurality of drying spaces viewed in said vertical direction from an infeed into the drying device to an outfeed of the drying device increases in size from a first group of said plurality of individual groups to a subsequent group of said plurality of individual groups.

13. The method according to claim 12, wherein said plurality of individual groups are arranged and configured such that said speed of the fibrous web an individual of said plurality of groups is controlled separately.

14. The method according to claim 3, further comprising the step of providing a drying medium supply system allocated to supply at least one individual of said plurality of blower devices, said drying medium to be supplied to a drying space and said drying medium enriched with moisture from said drying space is led between two adjacent of said plurality of blower devices of one of said plurality of blower units or of different of said plurality of blower units in a loop.

15. The method according to claim 14, said loop having a plurality of in-line heating devices.

16. The method according to claim 15, said width of an individual of said plurality of drying spaces is variably adjustable in a machine direction.

17. The method according to claim 1, further comprising the step of severing the fibrous web one of consecutively and simultaneously between individual said web guidance path segments if one of a malfunction and a web break occurs.

18. A drying device for drying fibrous webs, the drying device comprising:

a plurality of blower devices arranged on a pair of opposing sides of a theoretical web guidance path and defining a drying space therebetween and arranged extending in a cross direction of the drying device and extending in a vertical direction of the drying device with a deviation of up to and including ±20°, said plurality of blower devices limiting a plurality of said drying spaces progressing in said vertical direction, said plurality of drying spaces progressing in said vertical direction being arranged adjacent to each other in a machine direction to accommodate a plurality of guidance path sections, said plurality of blower devices being configured for applying a drying medium onto the fibrous web guided in said plurality of drying spaces; and

a plurality of turn rollers above and below an individual of said plurality of drying spaces, two of said plurality of turn rollers being allocated to an individual of said plurality of drying spaces for connection with adjacent said drying spaces defining said plurality of guidance path sections, said two turn rollers being configured for transferring the fibrous web between two adjacent of said plurality of drying spaces.

19. The device according to claim 18, wherein individual of said plurality of blower devices always arranged on a pair of opposing sides of an individual web guidance path section represent a single blower unit, said individual of said plurality of blower devices being subdivided into a plurality of blower zones in at least one of said cross direction of the drying device and said vertical direction of the drying device, the device further comprising a controller for at least one of individual and joint control of a plurality of said individual blower zones.

20. The device according to claim 19, said plurality of blower each including a plurality of blow boxes arranged in said vertical direction in a plurality of blower towers which are arranged extending in said cross direction of the drying device, an individual of said blower towers being supported on a frame.

21. The device according to claim 19, further comprising a drying medium supply system allocated to at least one of said plurality of blower devices.

22. The device according to claim 21, further comprising a plurality of recirculating blowers and a heating device, said plurality of recirculating blowers being arranged on a pair of opposing sides of said single blower unit, said plurality of recirculating blowers each having a suction side connected with one of said plurality of drying spaces and a pressure side connected with one of said plurality of blower devices of said blower unit, forming a circulation stream, wherein said heating device is upstream from said connection of said pressure side with said one blower device.

23. The device according to claim 22, said recirculating blowers being allocated to one of said plurality of blower devices and arranged in said vertical direction one above another and supported in a blower tower, said blower tower being formed one of separately and as a component of said frame.

24. The device according to claim 21, said drying medium supply system including at least one fresh air supply and at least one exhaust air removal connected with at least one loop, said fresh air supply and said exhaust air removal having no fluidic connection with each other.

25. The device according to claim 24, said fresh air supply and said exhaust air removal being coupled thermally through a heat exchanger.

26. The device according to claim 25, wherein always a plurality of said drying spaces arranged parallel to each other and extending in said cross direction and said vertical direction of the drying devices and said plurality of turn rollers coupling said drying spaces form a group, the device including at last two groups arranged and configured such that an extension of said plurality of web guidance path sections progressing through individual of said plurality of drying spaces viewed in said vertical direction from an infeed into the drying device to an outfeed from the drying device increases in size from a first group of said at least two groups to a subsequent group of said at least two groups.

27. The device according to claim 26, further comprising a controller allocated to at least one of said at least two groups for controlling a speed of the fibrous web.

28. The device according to claim 27, said controller configured for controlling a rotational speed of said plurality of turn rollers.

29. The device according to claim 28, said controller configured for adjusting a width of at least one individual of said plurality of drying spaces in said machine direction.

30. The device according to claim 29, said single blower unit being a plurality of blower units and the controller including one of rotatable and pivoted mounting units for two adjacently located of said plurality of blower devices of different of said plurality of blower units, said mounting units including one of rotatable and pivoted rocker arms on which said plurality of blower devices are flexibly hinged at a plurality of predetermined distances to a pivot point in a plurality of different mounting regions, said rocker arms including a force application surface for an adjusting device.

31. The device according to claim 30, wherein said plurality of rotatable or pivoting mounting units for a plurality of always adjacently arranged of said plurality of blower devices are forcibly coupled in regard to their respective actuation.

32. The device according to claim 18, further comprising a knock-off device configured for one of simultaneous and consecutive movement between two of said plurality of drying spaces.