Device for drying a printed material web

Abstract

The invention relates to a device (8) for drying a printed material web (6). The device comprises at least two drying units (22), each drying unit (22) having a radiator device (26) arranged below the conveying area (16) and having a plurality of infrared radiators (36) and a radiator ventilation device (38) for supplying air (A) to the infrared radiators (36) and the conveying area (16), a radiator suction device (28) arranged downstream of the radiator device (26) in the drying unit longitudinal direction (L) for supplying air (A) from the radiator ventilation device (38) into the conveying region (16), and a first air knife (30) arranged upstream of the radiator device (26) in the drying unit longitudinal direction (L) for supplying air (A) from the radiator ventilation device (38) into the conveying region (16), the device is used for generating an air jet (K) to release a laminar boundary layer on the material web (6). In each case, an intermediate suction device (42) is arranged between the drying units (22) for sucking off the evaporated solvent.

Description

Technical Field

[0001] The invention relates to a device for drying a printed material web with infrared radiators. In this case, the material web is in particular a paper, cardboard or carton web or a film web. Background Art

[0002] When printing a material web, printing ink is applied to the material web by a printing device. If solvent- and / or water-containing printing inks are used, infrared radiation is advantageously applied to the material web after printing. The evaporation of the water and / or solvent by the infrared radiation thins the printed material web.

[0003] For example, DE 10 2005 046 230 A1 discloses a rotary printing press comprising one of a plurality of printing units wherein downstream of the last printing unit in the direction of the transport path of the printed paper is a drying unit having at least one infrared ink dryer.

[0004] Furthermore, DE 10 2018 122 910 A1 discloses an infrared heating unit for drying ink. Summary of the Invention

[0005] The object of the present invention is to provide a particularly suitable device for drying printed material webs. In particular, with this device the most efficient drying can be achieved.

[0006] With regard to the device, this object is achieved according to the invention by the features of claim 1. Advantageous developments and embodiments are the subject matter of the dependent claims.

[0007] The device is provided and arranged to dry a printed material web, in particular for drying printing ink (ink) applied to the material web.Preferably, the material web is a paper web, a cardboard web, a carton web or a film web.

[0008] The apparatus comprises at least two, i.e., two or more, for example, three, four, five, or six drying units. These are conveniently arranged one behind the other along the material web. The drying units are arranged in series with respect to the material web. Thus, during operation of the apparatus, the material web is continuously processed by the drying units.

[0009] Each drying unit includes an irradiator device arranged below the material web's conveying area, i.e., below the area through which the material web is conveyed during operation of the device. The irradiator device includes a plurality of infrared irradiators, i.e., a single irradiator or more than one irradiator, for example, 10, 20, 30, 40, 50, or 60 irradiators. These devices are provided and arranged to irradiate the material web, in particular its printed side, with infrared radiation to evaporate water and / or solvent.

[0010] The infrared radiators of the respective radiator devices are preferably arranged adjacent to one another in a direction transverse to the material web or transverse to the longitudinal direction of the respective drying unit. Preferably, the infrared radiators can be controlled individually, or the two outer radiators can be controlled, in particular switched on or off. In this way, only those infrared radiators arranged directly above the material web are operated. In other words, the number and / or arrangement of the infrared radiators used for the drying process can be adapted to the respective width of the different material webs, so that only the infrared radiators irradiating the material web are operated.

[0011] Furthermore, it is preferred that the radiator power and / or the temperature of the infrared radiators of one of the drying units can be adjusted independently of the radiator power and / or the temperature of the infrared radiators of the other drying units.

[0012] The radiator ventilation device of the radiator system is configured to supply air to the infrared radiators to control their temperature and to convey the air to a conveying area. Thus, the radiator ventilation device conveys (temperature-controlled) air to the plurality of infrared radiators, and the heated air is conveyed to the conveying area during the cooling process and, during operation of the device, to the material web. The air conveyed to the conveying area thus transports solvent or water vapor evaporated in the region of the radiator system, preventing the infrared radiation from reflecting off the solvent. Furthermore, the supplied air convectively dries the material web. The housing of the radiator system conveniently serves as a guide for the air conveyed by the radiator ventilation device.

[0013] Furthermore, each drying unit comprises a radiator suction device for supplying air from the radiator ventilation device to the conveying area. The radiator suction device is arranged in the direction of the respective drying unit downstream of the radiator device, which direction is referred to as the drying unit longitudinal direction.

[0014] Advantageously, the infrared radiation emitted by the radiator device of one drying unit, in particular its intensity and / or spectral composition, can be adjusted independently of the infrared radiation emitted or to be emitted by the radiator device of one of the other drying units. In this way, for each drying unit, infrared radiation specifically suitable for drying the material web can be adapted to the specific drying conditions of the material web.

[0015] Each drying unit also includes a first air knife (air blade) arranged upstream of its emitter device in the longitudinal direction of the drying unit. Here and below, an air knife is understood to be a device whose nozzle can emit a relatively flat, planar air jet. The first air knife is used to generate an air jet that releases, i.e., separates and removes, the laminar boundary layer drawn by the material web. This avoids or at least reduces the risk of the infrared radiation generated by the infrared emitters being reflected by this boundary layer, thereby reducing the drying power. This advantageously results in relatively efficient drying of the printed material web or printing ink applied to the material web.

[0016] Advantageously, the airflow, in particular its volume flow and / or flow rate, of the first air knife of one of the drying units can be adjusted independently of the airflow of the first air knife of another drying unit. In this way, the airflow from the corresponding first air knife of each drying unit can be adapted to the drying state of the material web. For example, the airflow rate of the drying unit located upstream in the direction of transport of the material web can be set relatively low to prevent the flow of printing ink.

[0017] In summary, the radiator arrangement is arranged between the first air knife and the radiator suction device with respect to the longitudinal direction of the drying unit.

[0018] In each case, the device also comprises an intermediate suction device, which is arranged, in particular, along the material web and / or between the two drying units in the longitudinal direction relative to the drying units. The intermediate suction device allows the supply air and / or solvent evaporated from the material web to be extracted, thereby preventing an enrichment of the air with solvent and / or uncontrolled evaporation of printing ink solvent in the region of the emitter device.

[0019] Advantageously, the material web is conveyed in or substantially in the longitudinal direction of the drying units through or along the respective drying units.

[0020] In summary, due to the use of at least two drying units (dryer units), the solvent or water can be removed from the material web at several locations on the material web. Thus, the drying efficiency is advantageously increased.

[0021] According to one advantageous embodiment, the first air knife is arranged such that the air jet generated thereby is inclined relative to the longitudinal direction of the respective drying unit. In other words, the plane formed by the air jet is inclined relative to the longitudinal direction of the drying unit. Consequently, the air jet has at least one velocity component that is opposite to, i.e., antiparallel to, the direction of transport of the material web (web travel direction) or opposite to the longitudinal direction of the drying unit. This increases the relative velocity of the air jet and the material web transported in or substantially in the longitudinal direction of the drying unit. Advantageously, this facilitates the release of the laminar boundary layer.

[0022] According to one advantageous refinement, each drying unit includes an air knife suction device for sucking the air ejected by the first air knife. In this case, the air knife suction device is arranged upstream of the first air knife in the longitudinal direction of the drying unit, i.e., the first air knife is arranged between the air knife suction device and the radiator device. This prevents the separating laminar boundary layer from penetrating into the area of ​​the respective radiator device. This advantageously increases the radiator power.

[0023] Particularly preferably, each drying unit comprises a second air knife which is arranged upstream of the first air knife (30) in the longitudinal direction (L) of the drying unit, in particular upstream of the air knife suction device. The first and second air knives form a so-called double air knife 24.

[0024] Furthermore, the second air knife is preferably arranged such that the air jet generated by the second air knife is inclined relative to the longitudinal direction of the drying unit of the respective drying unit. Thus, in a manner similar to that of the first air knife, the relative speed of the air jet emitted by the second air knife and the material web transported along or substantially along the longitudinal direction of the drying unit is increased.

[0025] The air from the first and / or second air knives is preferably temperature-controlled, in particular preheated. Thus, temperature-controlled air is delivered to the material web by means of the first and / or second air knives. This allows the air to absorb more water vapor or solvent. The air jets emitted by the first and / or second air knives also serve to convectively dry the material web.

[0026] In this case, the air knife suction device is used in particular to suck the supply air of the first air knife. The supply air of the second air knife, ie the air ejected by the second air knife, is advantageously sucked by the intermediate suction device.

[0027] According to a particularly preferred embodiment of the device, a conveying area for conveying the material web is provided, forming a channel (conveying channel, drying channel), which is particularly continuous along the conveying area. Parts of the channel are particularly defined by the drying unit and / or the intermediate suction device, and / or the drying unit or the intermediate suction device is arranged within the channel. The channel further reduces the risk of evaporated solvent escaping undesirably into the surrounding area of ​​the device.

[0028] Preferably, the suction device, called dead zone suction device, is arranged above the channel, ie outside the channel. For example, for each drying unit, there is advantageously a dead zone suction device, which is arranged outside the channel above the corresponding radiator device, thereby avoiding heat accumulation there.

[0029] According to an advantageous embodiment, a third air knife and / or a further suction device is arranged at the inlet of the passage for the material web and, in addition or as an alternative, at the outlet of the passage for the material web. By means of the third air knife or by means of the suction device, an outflow of evaporated solvent from the device is prevented.

[0030] The first, second and / or third air knife is appropriately oriented in such a way that the entire material web is acted upon by the respective air jet. In other words, the area in which the air jet strikes the material web is linear and extends transversely to the material web or transversely to the longitudinal direction of the respective drying unit.

[0031] According to a preferred embodiment, each drying unit includes a counter-film, wherein the conveying area is arranged between the radiator device and the counter-film. In other words, in each drying unit, the counter-film is arranged above the conveying area. Preferably, the counter-film includes a counter-film suction device, so that solvent evaporated from the material web on the side facing away from the radiator device can be sucked away.

[0032] Preferably, the reverse diaphragm suction device is configured in such a way that air is sucked from the edge regions of the material web, i.e. from the end regions of the material web, in a direction transverse to the longitudinal direction of the drying unit (widthwise). To this end, the reverse diaphragm suction device comprises, for example, two suction openings extending in the longitudinal direction of the drying unit, which are parallel to each other and spaced apart in a direction transverse to the longitudinal direction of the drying unit.

[0033] According to one suitable design, the side of the reflective membrane facing the material web, i.e., the side of the reflective membrane facing the radiator device, is designed to reflect infrared radiation. This way, infrared radiation emitted by the material web or penetrating the material web is reflected back onto the material web, thereby improving drying efficiency.

[0034] Preferably, in addition or as an alternative, the counter membrane includes a guide element. Advantageously, it extends transversely to the material web, i.e., transversely to the longitudinal direction of the drying unit. This serves to guide the material web in the conveying area. This ensures a defined position of the material web relative to the radiator device in the conveying area. To achieve high electrical resistance, the guide element is preferably made of or comprises ceramic. Optionally, the guide element can be made of steel, for example. To avoid damaging the material web, the material web advantageously has a smooth cross-section, i.e., without edges.

[0035] According to a preferred embodiment, the radiator suction device of the respective drying unit has a suction direction that forms an angle of less than 90°, in particular less than 45°, and preferably less than 30°, with the longitudinal direction of the drying unit. This suction direction is preferably oriented in the longitudinal direction of the drying unit. In this way, the aspirated air is directed in a targeted manner in the direction of transport of the material web. On the one hand, this prevents the material web from being drawn in the direction of the radiator device, or at least reduces the risk of such aspiration. As a result, the distance to the material web can be reduced. On the other hand, this ensures that the air is drawn in relatively evenly across the entire width of the material web.

[0036] According to an advantageous design, the air drawn by the reverse diaphragm suction device and / or the dead-slot suction device can be supplied to the first and / or second air knife in each drying unit. The air supply to the first and / or second air knife is thus fluidically connected and / or can be connected to the reverse diaphragm suction device and / or the dead-slot suction device. Because this air is relatively warm, further heating of the respective air knife is unnecessary, or only required to be reduced. Furthermore, the warm air can better absorb the solvent. Furthermore, cooling of the material web due to the air flowing out of the first or second air knife is avoided.

[0037] According to an advantageous embodiment, in each drying unit, the air drawn in by its radiator suction device can be fed to a heat exchanger, which is advantageously designed as a tube-to-tube heat exchanger, for energy recovery. The radiator suction device is thus fluidically coupled to the heat exchanger.

[0038] In one advantageous embodiment, the fan for the radiator ventilation device and the fan for the first and / or second air knife are separate from one another, i.e., structurally separated from one another. Additionally or alternatively, the fan for the radiator ventilation device and the fan for the first and / or second air knife can be regulated, in particular controlled, independently of one another. In this way, the temperature, volume flow, and / or flow velocity of the air flow in the radiator ventilation device can be adjusted independently of the injection characteristics of the first and / or second air knife.

[0039] According to an advantageous embodiment, the intake rate of the radiator ventilation device, i.e., the volume flow of air from the delivery area, is greater than the volume flow of air entering the delivery area of ​​the radiator ventilation device and is regulated, adjustable, controlled, and / or controllable. In particular, the intake rate is between 1.1 and 1.5 times the supply air rate. As a result, the solvent is removed from the area of ​​the respective radiator device in a specific manner.

[0040] In an advantageous embodiment, the infrared radiators of each drying unit are arranged adjacent to one another transversely to the longitudinal direction of the drying unit or transversely to the material web. By deactivating the external infrared radiators in this direction and / or by reducing the intensity of the infrared radiation emitted by these radiators, the radiant power can be adapted to material webs of different widths. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The embodiments of the present invention are explained in more detail below with reference to the accompanying drawings, in which:

[0042] Figure 1 Schematic representation of a device for producing a printed material web, comprising a printing press for applying printing ink to the material web, a device for drying the material web, and a cooling device for the material web,

[0043] Figure 2 Schematically shows a side view of a device for drying a material web, wherein the device has at least two drying units along the material web, each having a radiator arrangement,

[0044] Figure 3 One of the drying units is shown schematically on an enlarged scale, and

[0045] Figure 4 The ventilation diagram of the two drying units of the device is shown schematically.

[0046] In all figures, corresponding parts and dimensions always have the same reference numerals. DETAILED DESCRIPTION

[0047] Figure 1 A device 2 for producing printed material webs is schematically shown. This includes a printing device 4, which is designed here, for example, as a rotary printing press, in particular a flexographic printing press. Optionally, the printing device 4 is designed as an inkjet printer. In most cases, printing ink (ink) is applied to a material web 6 guided in the device 2 by means of the printing device 4, which is then Figure 1 The material web 6 is, for example, a paper web, a cardboard web, a carton web or a film web.

[0048] Regarding the conveying direction F of the material web, as Figure 1 As indicated by the arrow in , a device 8 for drying the printed material web 6 is arranged downstream of the printing unit 4. In order to dry the material web 6, it is conveyed in particular by this device 8. This device 8 is also referred to below as the drying device 8 for short. This serves in particular to dry the printing ink applied to the material web 6. To this end, the printed material web 6 is irradiated with infrared radiation by means of the drying device 8. By comparison, in Figure 2 and Figure 3 The device 8 is shown in detail in FIG (see also below).

[0049] A cooling device 10 having a plurality of cooling rollers 12 is arranged downstream of the drying device 8 with respect to the conveying direction F of the material web. Thus, the printed and dried material web 8 is fed to the cooling device 10 downstream of the drying device 8 so that the material web 6 heated by the infrared radiation is cooled.

[0050] Figure 2 The drying device 8 is schematically shown in a relatively detailed side view. The drying device has a channel, referred to as a conveyor channel 14. This includes a conveying region 16 for the material web 6, i.e., within a limited area. The material web 6 is conveyed within the conveying region 16 from a (channel) inlet 18 of the conveyor channel 14 to a (channel) outlet 20 of the conveyor channel 14. In this case, the material web is deflected in the conveyor channel 14 by guide rollers 72.

[0051] The drying device 8 comprises drying units 22, according to the embodiment shown here, two drying units 22. Each of these drying units 22 comprises a double air knife 24, an emitter device 26 and an emitter suction device 28, which are arranged one behind the other in a (drying unit) longitudinal direction L of the respective drying unit 22. In this case, the drying unit longitudinal direction L corresponds to the main extension direction of the conveying channel 14 in the region of the respective drying unit 22.

[0052] The respective dual air knife 24 comprises a first air knife 30 and a second air knife 32, with an air knife suction device 34 being provided between the first and second air knives 30, 32 for supplying air to the first air knife 30 and the aerosol entrained therein, particularly solvent or water vapor. In this case, the second air knife 32 is arranged upstream of the air knife suction device 34 in the longitudinal direction L of the drying unit. The two air knives 30, 32 are arranged such that the air jets emitted thereby are inclined relative to the longitudinal direction L of the drying unit. Thus, the air jets, originating from the nozzle of the respective air knife 30 or 32, are directed toward the channel inlet 18.

[0053] Preferably, the air jets generated by the first and second air knives 30, 32 extend over the entire width of the material web 6 and / or the transport channel 14. Thus, the air jets preferably extend across the entire width of the material web 6 in a direction perpendicular to the stretching plane.

[0054] By means of the first and second air knives 30 and 32 , a laminar boundary layer entrained along the material web 6 is released, thereby avoiding reflection of infrared radiation at this boundary layer in the region of the emitter device 26 in the longitudinal direction L of the drying unit.

[0055] In each drying unit 22, its radiator device 26 comprises a plurality of infrared radiators 36, which are arranged to emit infrared radiation for drying the printing ink. If the respective radiator device 26 has more than one infrared radiator 36, they are arranged adjacent to each other in a direction transverse to the longitudinal direction L of the drying unit, i.e., in the (width) direction B along the width of the material web 6.

[0056] Each radiator device 26 also includes a radiator ventilation device 38. This device directs air A toward the infrared radiators 36 of the corresponding radiator device 26 in order to control its temperature, in particular, to cool it. The radiator ventilation device 38 is arranged so that the generated air flow is directed toward the material web 6, that is, into the conveying area. Overall, the radiator ventilation device 38 is arranged so that the air A is radiated so that the air A first reaches the infrared radiators 36 and then reaches the material web 6. According to the embodiment shown here, the radiator suction device 28 has a suction direction S that forms an angle of less than 90°, approximately 45°, with the longitudinal direction L of the drying unit. Preferably, the air Air emitted from the radiator ventilation device 38 is drawn in in the longitudinal direction L of the drying unit. To this end, the respective radiator suction device 28 includes, for example, an air guide element 40. The radiator suction device 28 draws in the air A supplied from the radiator ventilation device 38 to the conveying area 16 and any aerosols absorbed therein, in particular, water vapor and / or solvents from the printing ink, by means of the radiator suction device 28.

[0057] In summary, the two drying units 22 comprise a double air knife 24 , wherein the radiator device 26 is arranged downstream of the double air knife 24 in the drying unit longitudinal direction L and the radiator suction device 28 is arranged downstream of the radiator device 26 in the drying unit longitudinal direction L.

[0058] In each case, an intermediate suction device 42 is arranged between the drying units 22. It is provided to suction solvent or water evaporated from the material web 6 in the region between the drying units 22 and, if necessary, to suction the supply air of the second air knives 32 of the drying units 22 following in the conveying direction F of the material web 6.

[0059] The drying units 22 and the intermediate suction device 42 are arranged below the conveying region and delimit the conveying region opposite the vertical direction H of the tunnel, i.e. opposite a direction perpendicular to the longitudinal direction L and the width direction B of the drying unit. In other words, the intermediate suction device 42 and the drying units 22 form the tunnel boundaries. On the opposite side, the tunnel is delimited by the tunnel wall 74.

[0060] In order to avoid an accumulation of heat in the region above the conveying tunnel 14, a dead zone suction device 64 is arranged there, i.e. outside the conveying tunnel 14.

[0061] Each drying unit 22 comprises a counter film 44 which delimits the conveying region in the vertical direction H of the tunnel. In this case, the material web 6 is conveyed in the conveying region between the counter film 44 and the radiator device 26 (radiator unit). In other words, in each drying unit 22, the conveying region 16 is arranged between the infrared radiator 36 and the counter film 44.

[0062] The side 48 of the respective counter film 44 facing the conveying region 16, i.e. facing the material web 6, is configured to reflect infrared radiation, in particular to reflect the infrared radiation emitted by the infrared radiator 36. Furthermore, the respective counter film 44 comprises guide elements 46 for guiding the material web 6, which are arranged on its side 48 facing the material web 6. These guide elements 46 are preferably formed from ceramic and / or have a smooth cross section in a cross-sectional plane perpendicular to the width direction B, i.e. without edges.

[0063] Each counter film has a counter film suction device 62 by means of which water and / or solvent evaporated from the material web 6 on the side facing away from the respective radiator device 26 can be sucked off.

[0064] According to the embodiment shown here, the drying device 8 comprises, on the tunnel inlet side, a further drying unit 50 which has a radiator device 26 and a radiator suction device 28. The further drying unit 22 comprises a further double air knife 52 with two third air knives 54, wherein these air knives 30, 32 are configured such that the air jets emitted therefrom are perpendicular to the longitudinal direction L of the drying unit or even inclined in the longitudinal direction L of the drying unit, in comparison to the first and second air knives 30, 32 of the other drying units 22. Thus, it is avoided that evaporated water and / or solvent undesirably escapes through the tunnel inlet 18 to the surroundings of the drying device 8.

[0065] Furthermore, an end suction device 56, a further air knife 58 and a circulating air suction device 60 are arranged on the tunnel outlet side in order to prevent evaporated water or solvent from escaping through the tunnel outlet 20 to the surroundings of the drying device 8.

[0066] Figure 4A schematic diagram of the ventilation system for two drying units 22 is shown. Thus, for each drying unit 22, air containing relatively little or no solvent or water vapor, drawn in by the dead-slot suction device 64 and the reverse diaphragm suction device 62, can be supplied to the dual air knives 24, namely the first air knife 30 and the second air knife 32, to generate corresponding air jets. In other words, the first air knife 30 and the second air knife are connected to the reverse diaphragm suction device 62 and the dead-slot suction device 64 on the air supply side.

[0067] In each case, the air A drawn in from the radiator suction device 28 is first supplied to a heat exchanger 66 , which is advantageously configured as a tube-to-tube heat exchanger.

[0068] Furthermore, in the corresponding drying unit 22, the fan 68 for the radiator ventilation device 38 is configured separately from the fan 70 for the dual air knife 24. The two fans 68 and 70 can be regulated independently of each other. Therefore, the air supply to the dual air knife 24 can be regulated independently of the air supply to the radiator ventilation device 38. In particular, the volume flow rate, air temperature, and / or flow rate of the supply air to the dual air knife 24 can be regulated independently of the volume flow rate, air temperature, and / or flow rate of the supply air to the radiator ventilation device 38, and vice versa.

[0069] For the selective suction of aerosols in the area of ​​the infrared radiator 36, the suction rate of the radiator suction device 28, i.e. the amount of air sucked in per unit time by means of the radiator suction device 28, is preferably between 1.1 times and 1.5 times the air supply rate of the radiator ventilation device 38, i.e. the amount of air supplied per unit time by means of the radiator ventilation device 38.

[0070] The present invention is not limited to the above-described embodiments. Rather, within the scope of the claims, those skilled in the art may also derive other variations of the present invention therefrom without departing from the subject matter of the present invention. Furthermore, in particular, all individual features described in conjunction with the embodiments and / or claims may also be combined with one another in other ways without departing from the subject matter of the present invention.

[0071] Reference Signs List

[0072] 2 Equipment for producing printed material webs

[0073] 4 Printing device

[0074] 6 Material Web

[0075] 8 Devices

[0076] 10 Cooling device

[0077] 12 cooling rollers

[0078] 14 (transport) channel

[0079] 16 Conveying area

[0080] 18 Entrance

[0081] 20 Exit

[0082] 22 Drying Units

[0083] 24 Double Air Knife

[0084] 26 Radiator equipment

[0085] 28 Radiator suction device

[0086] 30 First Air Knife

[0087] 32 Second Air Knife

[0088] 34 Air knife suction device

[0089] 36 Infrared radiators

[0090] 38 Radiator ventilation device

[0091] 40 Air guide element

[0092] 42 Intermediate suction device

[0093] 44 Reverse diaphragm

[0094] 46 Guide element

[0095] 48 Reverse diaphragm side

[0096] 50 Another drying unit

[0097] 52 Another pair of air knives

[0098] 54 The Third Air Knife

[0099] 56 Suction device

[0100] 58 Another Air Knife

[0101] 60 Circulating air suction device

[0102] 62 Reverse diaphragm suction device

[0103] 64 Dead zone suction device

[0104] 66 Heat Exchanger

[0105] 68 Fans for radiator ventilation

[0106] 70 Fans for the first and second air knives

[0107] 72 guide roller

[0108] 74 passage wall

[0109] A air

[0110] B width direction

[0111] F conveying direction

[0112] H vertical direction

[0113] L longitudinal direction of drying unit

[0114] S suction direction

Claims

1. A device (8) for drying a printed material web (6), in particular a paper web or a cardboard web or a carton web, comprising - at least two drying units (22), -in, Each of the drying units (22) has an radiator device (26) arranged below the conveying area (16) for the material web (6), comprising a plurality of infrared radiators (36) and a radiator ventilation device (38) for supplying air (A) to the infrared radiators (36) and the conveying area (16), - a radiator suction device (28) arranged downstream of the radiator device (26) in the longitudinal direction (L) of the drying unit, for supplying air (A) from the radiator ventilation device (38) into the conveying area (16), and a first air knife (30) arranged upstream of the radiator device (26) in the longitudinal direction (L) of the drying unit for generating an air jet (K) for releasing a laminar boundary layer on the material web (6), - wherein an intermediate suction device (42) is arranged between each of the drying units (22) for sucking out evaporated solvent and / or water vapor.

2. The device (8) according to claim 1, It is characterized by: The first air knife (30) of the respective drying unit (22) is arranged to generate an air jet (K) that is inclined relative to the longitudinal direction (L) of the drying unit.

3. The device (8) according to claim 1 or 2, It is characterized by: Each of the drying units (22) has an air knife suction device (34) for sucking air ejected from the first air knife (30), wherein the air knife suction device (34) is arranged upstream of the first air knife (30) along the longitudinal direction (L) of the drying unit.

4. The device (8) according to any one of claims 1 to 3, It is characterized by: Each drying unit (22) has a second air knife (32), which is arranged upstream of the first air knife (30) and / or upstream of the air knife suction device (34) along the longitudinal direction (L) of the drying unit, and / or, wherein the second air knife (32) is arranged so that the air jet (K) generated is inclined relative to the longitudinal direction (L) of the drying unit.

5. The device (8) according to any one of claims 1 to 4, It is characterized by: The conveying area (16) for the material web (6) is enclosed to form a conveying channel (14), in particular continuously, and / or a dead zone suction device (64) is arranged above the conveying channel (14) to avoid heat accumulation.

6. The device (8) according to claim 5, It is characterized by: A third air knife (54) and / or a suction device (56) is arranged at the inlet (18) and / or outlet (20) of the transport channel (14) for the material web (6) to prevent evaporated solvent from escaping from the transport channel (14).

7. The device (8) according to any one of claims 1 to 6, It is characterized by: Each drying unit (22) has a counter membrane (44), wherein the conveying region (16) is arranged between the infrared radiator (36) and the counter membrane (44).

8. The device (8) according to claim 7, It is characterized by: The side (48) of the counter membrane (44) facing the conveying region (16) is designed to reflect infrared radiation.

9. The device (8) according to claim 7 or 8, It is characterized by: The counter membrane (44) has a guide element (46) for guiding the material web (6) in the conveying area (16).

10. The device (8) according to any one of claims 1 to 9, It is characterized by: The radiator suction device (28) of the respective drying unit (22) has a suction direction which makes an angle of less than 90°, preferably less than 45°, in particular less than 30° with the longitudinal direction (L) of the drying unit.

11. The device (8) according to any one of claims 1 to 10, It is characterized by: Air sucked from the reverse diaphragm (44) and / or from the dead zone suction device (64) may be supplied to the first air knife (30) and / or the second air knife (32).

12. The device (8) according to any one of claims 1 to 11, It is characterized by: The air (A) drawn from the radiator suction device (28) can be supplied to a heat exchanger (66), in particular a tube-to-tube heat exchanger.

13. The device (8) according to any one of claims 1 to 12, It is characterized by: The fan (68) for the radiator ventilation device (38) and the fan (70) for the first air knife (30) and / or for the second air knife (32) are separate from each other and / or can be adjusted independently of each other.

14. The device (8) according to any one of claims 1 to 13, It is characterized by: The suction rate of the radiator suction device (28) is adjustable and / or is set to be greater than the air supply rate of the radiator ventilation device (38), in particular between 1.1 and 1.5 times greater.

15. The device (8) according to any one of claims 1 to 14, It is characterized by: The infrared radiators (36) of the respective radiator devices (26) are arranged adjacent to one another in a direction transverse to the longitudinal direction (L) of the drying unit.

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