EP1795347A2 - Support for cooling roll and method of cooling a web guided through the support - Google Patents

Abstract

The unit has a set of cooling rollers (1) that are embraced partially by a material web, where one of the rollers is an insulated roller with a cylindrical base plate (2), and an outer body (4) that guides a heat transfer medium. The outer body surrounds the base plate at its casing surface, where the base plate and the outer body are thermally insulated from each other. An outer surface of the outer body comprises a structuring. An independent claim is also included for a method for cooling a material web.

Description

Cooling roller stand and a method in each case for cooling a material web passed through

The invention relates to a cooling roll stand and a method in each case for cooling a material web passed through according to the preamble of claim 1, 19, 33 or 44.

From the WO 2004/039588 A1 is a rotating body of a printing press with a bale known. The bale includes a base and an outer body, wherein the outer body has channels for the passage of a tempering agent, and the main body is thermally insulated from the outer body.

The EP 1 201 429 A2 describes a method and apparatus for cooling a web of material. An arrangement of the cooling rolls is proposed in such a way that a material web along a web path partially wraps around the cooling rolls, wherein the web path runs substantially meander-shaped. Chill rolls of smaller diameter are used without any special internal structure.

From the EP 1 046 500 B1 it is known to arrange cooling rolls with a diameter smaller than 300 mm in such a way that the material web wraps around them in wrap angles between 180 ° and 270 °.

From the EP 0 943 435 A1 a cooling roll is known, which is supplied with a cooling medium and having an inlet and a drain, which are arranged on opposite end faces of the roll. An embodiment of the flow region within the cooling roll ensures that a uniform temperature profile across the width of the roll is achieved.

By the DE 202 07 526 U1 a device for increasing the heat transfer to a cooling roller is known, wherein the cooling roller arranged in a cooling roller stand cools a material web printed by a printing machine, wherein in the cooling roller stand at least one cooperating with the cooling roller impression roller is provided.

By the EP 0 516 924 A1 a device for increasing the heat transfer to cooling rollers of offset printing machines is known, wherein for reducing the present between the material web and the cooling roller air gap a charging electrode row is arranged, wherein the charging electrode row in the inlet region of the material web and the cooling roller is arranged.

By the DE 94 19 702 U1 a device for producing printed sheets is known, wherein on the side facing away from a first cooling roller side of the printed, hot-dried in a dryer and then cooled by running on at least the first cooling roller web in the transport direction in front of this cooling roller an electrostatic charging electrode is provided transversely to the transport direction , The device according to the DE 94 19 702 U1 also has the task to reduce the formation of waves of webs after drying. For this purpose, a device is provided before entering the web in a chill roll stand or in front of the first chill roll, which deflects the material web with a smaller diameter twice over blow rods. It is also proposed here to arrange a Coanda plate parallel to the material web, whereby air can be blown into the gap between it and the web by means of a nozzle, whereby the web is attracted to the Coanda plate without touching it.

By the EP 1 318 014 B1 is a device for fixing a moving in the direction of transport, to be printed material web of a dielectric material on a to the cliché of the format cylinder pressed steel presses a flexographic printing known.

By the WO 01/85454 A1 is a cylinder with a non-rotatable support and thereon by rolling bearings mounted rotatable jacket known, wherein at least one first roller bearing is arranged with an associated adjusting device for varying the distance in the radial direction between the carrier and the jacket, and wherein at least one second rolling bearing the distance in the radial direction between the carrier and the jacket is arranged fixed unchangeable, wherein the rolling bearing is arranged with adjusting device at the end of the jacket.

From the EP 1 046 874 B1 is a dryer with an integrated cooling unit known. In order to avoid air layers between the chill roll surface and the material web, it is proposed to accommodate the chiller unit in the same housing in which the dryer is located. Since the web between dryer and chill roll stand are no longer exposed to the conditions of the surrounding atmosphere, the adhesion of boundary layers of cold air on both sides of the web can be prevented. In this way, the sooting at the dryer outlet can be avoided because the dryer outlet is not connected to the surrounding atmosphere. In the cooling unit, the material web assumes a substantially vertically oriented path. Details of the cooling unit are not described.

From the EP 0 812 685 A1 is a suction device for air extraction in the region of the inlet gap between a web and cooling roller of a web offset printing known. With a suction device, the boundary layer adhering here to the web is sucked off. According to a preferred embodiment, means may be provided for peeling off the air entrained by the material web on the housing wall of the suction device and thus for better suction. These means may be Abschälbleche or blow-off nozzles. Blow-off nozzles are included arranged so that they blow against the direction of the web air. Through these blow-off nozzles, the laminar flow of the air is torn open at the material web surface and swirled, so that a subsequent suction can take place. The blow-off nozzle is designed as a slot nozzle whose slot extends over the entire length of the cooling roller.

From the US 42 65 384 A , of the US 43 84 666 A as well as the US 47 18 178 A Various nozzle arrangements or air rails are known, which are arranged in a hot air dryer for sheet material. The nozzles are designed to apply the Coanda effect of streaming air to the web.

The US 53 95 029 A describes a nozzle chamber assembly for use in a web transport apparatus in which the webs are to be transported horizontally. Here, nozzles are proposed in which the flow characteristics of the individual nozzles can be changed in order to use the transport device for different material webs under the same conditions.

Furthermore, it is known to arrange Abrakelsysteme in the dryer and at the outlet of the dryer, which should avoid that the paper web entrains an air layer with exhaust gases and high humidity.

The invention has for its object to provide cooling roll stand and a method each for cooling a material web passed therethrough, which allow more effective cooling of the guided through the cooling roll stand material web especially at a higher production speed of the web printing machine.

The object is achieved by the features of claim 1, 19, 33 or 44 solved.

The achievable with the present invention consist in particular that a more effective cooling of the web is achieved, which allows a higher production speed of the printing press, since even at their higher production speed sufficient cooling power is provided. Because of the proposed measures in particular a heat transfer between the cooling rollers and the material web is improved. On the other hand, by the use of thermally insulated cooling rollers material saving or a size minimization of a cooling roll stand can be achieved. Furthermore, it is advantageous that a structurally integrative and thus space-saving solution has been found for the application of a contact force caused by a impression roller and for the formation of the electrostatic field.

It is thus advantageously used in the cooling roll stand at least one roller which comprises a base body and an outer body thermally insulated from the base body, wherein channels are provided for the flow through a temperature control in the outer body. This roll is referred to below as an insulated chill roll.

Various web paths and wrap angles may be provided as well as additional cooling assistants.

Another advantage that can be achieved with the invention is that a laminar flow between the material web and the cooling roll, which occurs in particular at a high running speed of the material web, is minimized, preferably eliminated.

Moreover, it is advantageous that with the invention greater energy savings can be achieved are. Furthermore, the smoke at the dryer outlet can be minimized. Another advantage results in the longer life of the cooling rollers due to a reduced condensate deposit on the surface of these. In this case, material webs with web speeds of more than 15 m / s can be effectively cooled.

Embodiments of the invention are illustrated in the drawings and will be described in more detail below.

Show it:

Fig. 1

an insulated chill roll in longitudinal section without hatching;

Fig. 2

the insulated cooling roller of Figure 1 in a cross-sectional view without hatching.

Fig. 3

a perspective view of an insulated sleeve with flow channels;

Fig. 4

a cooling roll stand with insulated cooling rolls according to a first embodiment;

Fig. 5

a chill roll stand according to a second embodiment;

Fig. 6

a chill roll stand according to a third embodiment;

Fig. 7

a cooling roll stand according to a fourth embodiment;

Fig. 8

a cooling roll stand according to a fifth embodiment;

Fig. 9

a cooling roll stand according to a sixth embodiment;

Fig. 10

a cooling roll stand according to a seventh embodiment;

Fig. 11

a cooling roll stand according to an eighth embodiment;

Fig. 12

a cooling roll stand according to a ninth embodiment;

Fig. 13

a cooling roll stand according to a tenth embodiment;

Fig. 14

a diagram of a pipe connection for cooling lines in a cooling roll stand;

Fig. 15

a chill roll stand with a impression roller;

Fig. 16

a chill roll stand with two air doctor blades in a first arrangement;

Fig. 17

a chill roll stand with two air doctor blades in a second arrangement;

Fig. 18

the cooling roller stand shown in Figures 15 to 17 in a perspective view.

Fig. 19

a schematic representation of an output of a hot air dryer and a subsequent chill roll stand;

Fig. 20

a schematic representation of an apparatus for cooling a heated web before it enters the chill roll stand;

Fig. 21

a detailed view of the device of FIG. 20;

Fig. 22

a schematic representation of the device components shown in Fig. 21;

Fig. 23

a representation of the pressure and air flow distribution on a material web before its contact with the first cooling roller in the cooling roller stand.

An insulated cooling roller 01 and a method for producing such a cooling roller 01 with a thermally insulated base body 02 are explained below with reference to FIGS. 1 to 3.

On a over the axial length of the insulated cooling roller 01 extending preferably closed cylindrical surface 03 of the body 02, a cylindrical sleeve 04 is pushed, wherein the sleeve 04 along its circumference several cavities 07 in the form of z. B. axially to the body 02 extending grooves 07, wherein preferably each groove 07 is usable as a flow channel. About the axial length of the insulated cooling roller 01 are preferably a plurality of sleeves 04 preferably the same width z. B. strung together by slipping on the insulated cooling roller 01 such that all grooves 07 on the outer surface of the sleeves 04 each supplement to a over the axial length of the insulated cooling roller 01 extending continuous flow channel. However, the sleeves 04 can also z. B. in different widths, so that different widths sleeves 04 can be assembled to almost any axial length of the insulated cooling roller 01.

On a front side 08 of the insulated cooling roller 01 or on an end face 09 of a extending through the cooling roller 01 shaft 11, a channel-like inlet 12 is provided for introducing a heat transfer medium into the cooling roller 01, wherein the heat transfer medium z. B. in the interior of the shaft 11 through the cooling roller 01 through to close to the opposite second end face 10 of the cooling roller 01 is passed.

By means of preferably a plurality of radial bores 13, the heat transfer medium is fed from there to the front openings of the grooves 07 of the cooling roller 01 outermost sleeve 04 and introduced into the groove 07 formed as flow channels, after which the heat transfer medium, the grooves 07 in the direction of the first end face 08 of Cooling roller 01, at which the heat transfer medium was introduced into the cooling roller 01, flows through. By means of further radial bores 14, the heat transfer medium emerging at the front-side openings of the grooves 07 of the last sleeve 04 emerging in the axial direction of the cooling roller 01 can be fed out of the cooling roller 01 to a channel-like outlet 16 for the collected removal of the heat transfer medium.

In this embodiment, the sleeves 04 are preferably made of a plastic z. B. manufactured in an injection molding and consist for. B. of a polyamide. In particular, the sleeves 04 are made of a thermally insulating material. The arranged on the outer surface of the sleeve 04 grooves 07 are preferably formed during injection molding of the sleeve 04. However, the grooves 07 can also be milled on the outer surface of the sleeve 04.

After attaching the required for the entire axial length of the cooling roller 01 sleeves 04 on the body 02 and the alignment of their respective grooves 07 to form continuous flow channels, the sleeves 04 on the body 02 preferably by a cohesive connection, z. B. by gluing, fixed and secured. Thereafter, a z. B. formed as a cylindrical tube outer shell 17 applied to the juxtaposed sleeves 04 such that the introduced into the sleeves 04 grooves 07 are covered. The sleeves 04 together with the outer shell 17 form an outer body 04, 07, 17. In this embodiment, the outer body 04, 07, 17 belonging sleeve 04 forms the thermal insulation to the body 02. But it is also possible, the body 02 with a to provide thermally insulating coating and the outer body 04, 07, 17 in one piece from good heat-conducting material to manufacture.

Webs 18 formed between the individual grooves 07 prevent leaks at which the heat transfer medium flowing through the flow channels could uncontrollably pass from a groove 07 into an adjacent groove 07 (FIGS. 2 and 3). The preferably thin-walled outer shell 17 is z. B. positively slipped onto the sleeves 04 and to the sleeves 04 and / or on the body 02 preferably cohesively z. B. attached by welding or gluing. Thus, at least one cylindrical sleeve 04 made of a thermally insulating material is inserted into the space between the surface 03 of the base body 02 and the inside 19 of the outer shell 17. The outer shell 17 is preferably made of a corrosion-resistant and wear-resistant metallic material. Preferably, the surface of the outer body 04, 07, 17 is chromed. A profiling or engraving of the surface can also be provided.

Various embodiments and roller arrangements of a cooling roller stand 21 are shown in FIGS.

In FIGS. 4 to 8, embodiments are shown with a wrap angle of the material web <180 °. All cooling rollers 01 are in this case designed as insulated cooling rollers 01, these preferably have a diameter of 200 mm.

Fig. 4 shows a chill roll stand 21 with six (optionally 8) insulated chill rolls 01. A web 22 enters the chill roll stand 21 and wraps around its path several insulated chill rolls 01, which are numbered with Roman numerals (I to VIII). The cooling rollers 01 _{I to V} are free-running in this embodiment. The first cooling roller 01 _I is adjustable with its longitudinal axis, so that the path can be varied. The cooling roller 01 _VI is driven by a drive 23. Optionally, the chill roll stand 21 with two further insulated chill rolls 01 _VII ; 01 _VIII be equipped (shown in dashed lines).

In Fig. 5 and 6 further cooling roller assemblies and material web paths are shown. The first cooling roller 01 _I is adjustable. A cooling roller 01 _V or 01 _{VI of} the arrangement is driven by a drive 23 respectively.

Figs. 7 and 8 show cooling roll stands 21 in which the cooling rolls 01 are arranged in "omega" shape. The in the web of the web 22 first arranged cooling roller 01 _I is in turn adjustable. The drive 23 drives one of the cooling rollers 01 _VII . Dashed lines show further cooling rollers 01, which can additionally be arranged in the cooling roll stand 21.

In FIGS. 9 to 13, chill roll stands 21 are shown, which are equipped both with conventional chill rolls 24 and with isolated chill rolls 01. The isolated cooling rollers 01 can be "pre-stored" in conventional chill roll stands, so to speak, in order to improve the cooling capacity, or also to be able to omit individual chill rolls and their drives. In addition to the preliminary storage of the insulated cooling rollers 01, mixed assembly, as shown in FIG. 13, is also possible.

14 shows a piping scheme for a cooling roll stand 21. It is advantageous that the feeds 12 and outlets 16 are arranged completely on the cooling flow side K of the cooling rolls 01 facing away from the drive side A. The construction of a cooling roll stand 21 is thereby greatly simplified technologically and structurally.

Fig. 15 shows an example of a modified cooling roller stand 21, in which in the direction (indicated by an arrow) of the web 22 z. B. four insulated cooling rollers 01 are arranged. The web 22 fed to the chill roll stand 21 has previously been provided with at least one printing unit of a printing press (not shown). printed, wherein the printing press the printing process with at least one ink z. B. in an offset printing process. The preferably designed as a web press printing machine is z. After printing on the material web 22, the ink applied thereto is dried in a dryer 32, in particular in a hot-air dryer 32 (FIGS. 19, 20), by the material web 22 the dryer 32 passes through, whereby the material web 22 is heated to above 100 ° C, for example up to 140 ° C. For further processing of the printed material web 22, z. B. to a chill roll stand 21 in the direction (indicated by another arrow) of the web 22 downstream folding unit (not shown), the web 22 must be cooled to about room temperature.

As can be seen from FIG. 15, the material web 22 wraps around the insulated cooling rollers 01 with the largest possible angle of wrap of z. B. 140 ° to 240 °, preferably more than 180 °.

To further improve the heat transfer between the cooling rollers 01 and the web 22 z. B. at the first, preferably in accordance with FIGS. 1 to 3 isolated executed cooling roller 01 _I after the inlet of the web 22 in the cooling roller stand 21 at least one impression roller 26 is provided, which formed as a roller with a comparison with the cooling roller 01 significantly smaller diameter is. The impression roller 26 is preferably adjustable by an adjusting device 27 to this first cooling roller 01 _I and / or from there. The adjusting device 27 is by means of a z. B. hydraulic, pneumatic or electric actuator 28, for example, a working cylinder or a motor, and a control device (not shown) preferably remotely operable, z. B. from a press belonging to the control console. The adjusting device 27 ensures that the impression roller 26 during production of the printing machine for cooling the material web 22 fixed, that is employed by applying a contact pressure, on the first cooling roller 01 _I. During the introduction of a Web start of the web 22 in the cooling roll stand 21 is the impression roller 26 of the cooling roller 01 _I parked.

The impression roller 26 can be compensated for bending in its axial extension, wherein the bending compensation takes place in particular via outer bearings in which a rotationally fixed carrier of the impression roller 26 is mounted. Inner bearings of the impression roller 26 carry a rotating jacket surrounding its carrier. To carry out the bending compensation 26 corresponding adjusting means (not shown) are provided in or on the impression roller. With these adjusting means along the axial extent of the impression roller 26 as uniform as possible line pressure to the cooling roller 01 _{I is} set so that the line pressure is increased neither in the side region of the impression roller 26 in the central region. Alternatively, radially adjustable support elements can be provided within the impression roller 26 in its axial direction as adjustment means, with the adjustment of which it can be ensured that the contact force remains constant transversely to the direction of travel of the material web 22.

The impression roller 26 are to improve the conditioning of the web 22 on the cooling roller 01 _I preferably two air knife 29; 31 assigned. The two air squeegee 29; 31 are on either side of the web 22 either facing each other arranged (Fig. 16), so that the web 22 between the two air knife 29; 31, or the one air knife 29 is arranged in the running direction of the material web 22 in front of the first cooling roll 01 _I and the air knife 31 acting on the other side of the material web 22 is arranged in the running direction of the material web 22 after the first cooling roll 01 _I (FIG. 17) ,

The proposed device can likewise have an electrostatic charging device with two electrodes to improve the contact of the material web 22 on the cooling roller 01 _I , wherein one of the electrodes bears against the impression roller 26 and the other electrode is formed by the cooperating with this impression roller 26 chill roller 01 _I. In this case, the cooling roller 01 _{I is} preferably connected as a grounded electrode. Between the impression roller 26, on which with a preferably controllable in its output voltage or controllable generator (not shown), a DC voltage z. B. of 30 kV is applied, and the cooling roller 01 forms an electrostatic field, which improves the installation of the web 22 on the cooling roller 01 _I by utilizing electrostatic attraction forces. The electrical voltage is the impression roller 26 z. B. via a spring contact plug (not shown). An alternative to the spring contact plug may be to contact the DC voltage without contact, z. B. over a spark gap, with a z. B. in the axial direction of the impression roller 26 extending, spaced from the lateral surface of the impression roller 26 electrode (not shown) to the impression roller 26, wherein the spark gap for reasons of explosion protection is preferably arranged or formed in an electrically insulated, encapsulated housing. Further modifications to the structure of the electrostatic field between the impression roller 26 and the cooling roller 01 are possible, such as the use of a grinding element made of plastic, wherein it in a conventional manner by the relative movement between the grinding element and impression roller 26 to a charge separation and thus charging the impression roller 26 is coming.

Fig. 18 shows the cooling roller stand 21 shown in Figs. 15 to 17 again in a perspective view. The lateral surface of the impression roller 26 can be designed as a single-layered or multi-layered (with a plastic or rubber elastic material, for example). For example, an insulator layer and / or a conductor layer and / or a semiconductor layer may be arranged on a steel core. A structure to be used may, for example, the WO 98/47802 A1 be removed.

As already mentioned, the web offset printing on both sides of the multi-color printed web, ie in particular the paper web, after their hot air drying a Cooling roller group supplied. The heated to about 110 ° C to 140 ° C web is to be brought to a temperature below 30 ° C. This cooling has the task of making the after hot air drying still very sticky ink film virtually tack-free, so that the print image has grown to the mechanical influences and stresses on the former, the folder and the rod jib. The cooling roller group consists of several, depending on the arrangement. B. two to five large-sized, highly polished steel cylinders of different arrangement. With the largest possible wrap angle of 140 ° to 240 °, the hot web is guided for removal against the cylinder through which coolant flows.

At higher web speeds of z. B. more than 10 m / s, especially at more than 15 m / s, increasingly occur on the cooling rollers problems with the web cooling and the Mineralölkondensatniederschlag. There are different causes for this. On the one hand, when the paper web exits the dryer, it is more or less surrounded by mineral oil vapors, some of which come out of the dryer and are caused by evaporation due to the web temperature. The hot web continues to adhere to an air boundary layer, with which the mineral oil vapors reach the chill rolls and can condense there on the surface. This can result in smearing and fouling of the printed image or deposition of ink on the chill roll. This can lead to a so-called chill roll plucking.

Another cause of the problems occurring at higher web speed is the formation of a speed-dependent air cushion between the cooling cylinder and the overlying material web. This heat-insulating air layer leads to a hindrance of the heat dissipation on the surface of the cooling cylinder, so that the heat transfer at the individual cooling cylinders decreases with increasing web speed. The larger the air cushion between paper web and cylinder, the greater the amount of condensates that can be deposited on the cooling cylinder and the lower the transferable to the web of cooling capacity.

In the prior art, various possibilities are known for the reduction of the air cushion. This is on the one hand the pressing of the web with a pressure roller. Furthermore, it is known to press the material web to the cooling roller by means of an air press with impact jet nozzles. It is also known to select smaller roller radii while increasing the number of cooling rollers in order to improve the cooling of the material web.

Another way to reduce the air cushion between the web and the cooling roller is the application of electrostatic effects. In this case, charge carriers are selectively applied to the material webs, which are attracted in this state by the grounded cooling roll surface. This results in an improved application of the material web to the cooling roller.

However, all of the prior art systems fail to provide adequate protection against the problems associated with high web speeds in a chill roll stand due to air and condensate layers entrained at the web surface.

It is proposed, prior to hitting a coming of a hot air dryer web on a first chill roll in a chill roll stand the web, z. B. paper web to blow with their transport direction opposite air flow of cold air. The cold air flow moves along the surface of the web towards the exit of the hot air dryer. As a result, the hot air layer flowing out of the dryer is torn off so that it can no longer act as an insulator between the paper web and the cooling roller. The opposite air flow causes a flow directly above the web and in their vicinity in the direction of dryer, thereby the exhaust gases with high humidity and Temperature with this air flow through the dryer specific output disposed. As a result, no additional suction device above the cooling roller group is required.

The opposing air flow, which preferably has ambient temperature, already results in a first cooling of the material web prior to entry into the first cooling roller, so that the cooling power provided by the cooling rollers can be made smaller than would be necessary without this air flow.

In a preferred embodiment, the air flow is inflated both on the top and on the underside of the material web. Due to resulting underpressure and overpressure areas, in addition to the tearing off of the laminar boundary layer, the material web is applied to the first cooling roller.

A device has a nozzle tube which extends transversely to the material web and extends over the entire width thereof. The nozzle tube is arranged in the web run in front of the first cooling roll of the cooling roll stand.

The nozzle tube advantageously has nozzle bores, which are distributed uniformly over the length of the nozzle tube. The nozzle tube has a connection for the purpose of flowing through with a suitable cooling medium. A suitable cooling medium is for example air, which passes under pressure the nozzle tube.

The nozzles of the nozzle tube are opposite to the direction of travel of the web. That is, when a compressed air is applied to the nozzle tube, an air flow is caused on the paper web through the nozzles of the nozzle tube, which is directed opposite to the running direction of the material web.

Preferably, the material web is arranged in each case a nozzle tube on both sides.

Advantageously, the nozzle tube or the nozzle tubes is arranged so that the "COANDA" effect is used.

19 shows a schematic representation of an outlet of a dryer 32, in particular hot air dryer 32, and a subsequent cooling roll stand 21. The web 22 leaves after printing the hot air dryer 32 through a so-called flue gas tunnel 33 in the direction of a movement arrow 34 shown. The web 22 is then in the chill roll stand 21 further conveyed, in which chill rolls 01; 24 of the type described above, d. H. in a thermally insulated or in a conventional embodiment, are arranged. The web 22 passes through the numbered with the Roman reference numerals I to IV cooling rollers 01; 24 with the largest possible wrap angle to achieve a high cooling capacity.

The temperature at which the material web 22 leaves the hot air dryer 32 increases for technological reasons with increasing web speed. For example, while a web 22 at a web speed of 13 m / s at the exit of the dryer 32 reaches about 110 ° C, due to the faster web transport at, for example, 15 m / s at the dryer exit a web temperature of 120 ° C and at 17m / s a web temperature of 130 ° C measurable.

Furthermore, at elevated web speeds from 15 m / s a strong smoke formation is observed at the exit of the flue gas tunnel 33. FIG. 19 shows flue-gas vortices 38 flowing by way of example with hatched arrows. It can be seen that parts of the flue-gas vortices 38 escape above the cooling-roll stand 21 into the environment, which usually requires an extraction system in this area (not shown).

With the material web 22, a laminar boundary layer is entrained, which is formed by hot condensate-containing air. In the vicinity of the flue gas tunnel 33, a laminar suction flow 39 is formed in the direction of the flue gas tunnel 33, which is symbolized by non-hatched flow arrows, with which clean, dry ambient air is sucked into the flue gas tunnel 33 against the direction of web travel.

Fig. 20 shows a chill roll stand 21 with a device for cooling a heated web 22 prior to its entry into the chill roll stand 21. The device for cooling a heated web 22 comprises at least one nozzle tube 41; 42, in a preferred embodiment, an upper nozzle tube 41 and a lower nozzle tube 42, which in the web run in front of the first cooling roller 01; 24 - I are arranged. The at least one nozzle tube 41; 42 has a distance of one to two meters to the exit of a hot air dryer 32.

The nozzle tubes 41 and 42 produce an air flow which runs along the surface of the material web 22 but opposite to the conveying direction. This counterflowing air flow generated by the nozzle pipes 41 and 42 causes a flow 43 (represented by blackened arrows) directly above the web 22 and in the vicinity, which is directed into the flue gas tunnel 33. As a result, the exhaust gases are disposed of with high humidity and temperature on the dryer-specific output or the flue gas tunnel 33 and pushed back into this. An additional suction device, which normally has to be arranged above the cooling roll stand 21, can advantageously be dispensed with. Furthermore, the air flow coming from the nozzles, which blows over the material web 22 at room or ambient temperature, already causes a first cooling of the material web 22 before its contact with the first cooling roll 01; 24 - I.

It can also be seen in this illustration that the flue-gas vortices 38 have a significantly smaller extent than in the embodiment according to FIG. 19 and not or only escape minimally into the environment.

FIG. 21 is a detailed view of the device according to FIG. 20 in a perspective view. FIG. The nozzle tubes 41 and 42 extend over the entire width of the material web 22 and have nozzle bores 44 for generating the counter-rotating air flow. The nozzle bores 44 have a diameter between 0.8 mm and 2 mm. Preferably, the size of the nozzle bores 44 is in the range of 1 mm to 1.5 mm.

The nozzle bores 44 may have a distance of 30 mm to 150 mm to each other. Preferably, this distance is 70 mm to 120 mm.

With reference to FIG. 22, advantageous dimensions and arrangements of the device in a cooling roll stand 21 will be explained. The nozzle tubes 41 and 42 are in a z. B. vertical distance y ₁ ; y ₂ spaced from the web 22, wherein this distance y ₁ ; y _{2 is} in the range of 10 mm to 300 mm, preferably between 50 mm and 130 mm. The distance y ₁ ; y _{2 of} the nozzle pipes 41; 42 of the web 22 must not be the same size on the bottom and top.

The upper nozzle tube 41 is preferably in the web running direction of the material web 22 approximately in a vertical plane with the longitudinal axis of the first cooling roller 01; 24 - I arranged. The distance x _{1 of} the upper nozzle tube 41 to the vertical plane may be arranged in the web running direction to about 100 mm in front of or behind the vertical plane. Preferably, the distance x ₁ -20 mm to + 20 mm.

The lower nozzle tube 42 is preferably arranged in the web running direction of the material web 22 approximately in a vertical plane with the longitudinal axis of the first cooling roller 01 24 - I. The distance x _{2 of} the lower nozzle tube 42 to the vertical plane may be arranged in the web running direction 200 mm to about 400 mm in front of the vertical plane. Preferably the distance x _{2 is} 250 mm to 350 mm.

The distance x _{3 of} the nozzle tubes 41; 42 to each other, measured on a horizontal plane, is in an advantageous embodiment, 100 mm to 300 mm, preferably 150 mm to 200 mm.

The nozzle bores 44 are directed at the material web 22 at an approach angle β in the opposite direction of travel. The angle of incidence β can be varied from 15 ° to 60 °, it is preferably in a range between 30 ° and 40 °.

The air flowing out through the nozzle bores 44 is preferably subjected to a pressure of 3 to 10 bar.

The air flow preferably has a temperature of 20 ° C to 40 ° C.

Based on Fig. 23, the self-adjusting flow and pressure conditions are shown on a device. Hatched is a zone of turbulent invisible cold flow 46, e.g. B. Outside the range of the cold flow 46 is an area of clean flowing laminar air flow 47. At the edge of the flow 46 form negative pressure areas 48, which have a force on the web 22 result. The resulting force vectors are indicated by the force arrows 49. As a result, a wave formation of the material web 22 and a better concern of the material web 22 on the first cooling roller 01; 24 - I reached.

The flow 46 reaches a flow velocity counter to the web running direction of 0.2 to 2 m / s. By this flow 46, a tearing off of the laminar boundary layer of condensate-containing air can actually be achieved.

The introduced at the bottom of the sheet air flow of the nozzle tube 42 generates a vacuum wedge 51 at the inlet between the first cooling roller 01; 24 - I and the material web 22, so that in addition the overpressure acting on the web upper side causes application of the material web 22 to the first cooling roll 01; 24 - I effects. If the upper nozzle tube 41 is not present, the ambient pressure acts on the material web 22.

The location of the cooling roller 01; 24 - II is selected in accordance with the air flow at the web underside such that also at the inlet between the web 22 and the second cooling roller 01; 24 - II creates a negative pressure, so that in addition a pressing of the material web to the second cooling roller 01; 24 - II can be achieved.

LIST OF REFERENCE NUMBERS

01

Chill roller, isolated

02

body

03

surface

04

shell

05

-

06

-

07

Cavity, groove

08

Front side, first (01)

09

Front side (11)

10

Front side, second (01)

11

wave

12

Intake

13

radial bore

14

radial bore

15

-

16

procedure

17

outer shell

18

web

19

inside

20

-

21

Chill roller stand

22

web

23

drive

24

Chill roller, conventional

25

-

26

impression roller

27

setting device

28

actuator

29

air knife

30

-

31

air knife

32

Dryer, hot air dryer

33

Flue gas tunnel

34

movement arrow

35

-

36

-

37

-

38

Flue gas vortex

39

intake flow

40

-

41

Nozzle tube, upper

42

Nozzle tube, lower

43

flow

44

nozzle bore

45

-

46

Flow, compressed air

47

Flow, laminar

48

Under pressure area

49

force arrow

50

-

51

Under pressure wedge

A

driving side

K

Cool river

x ₁

Distance nozzle tube (41) to the cooling roller (01, 24)

x ₂

Distance nozzle tube (42) to the cooling roller (01; 24)

x ₃

Distance between the nozzle tube (41; 42)

y ₁

Distance between nozzle tube (41) and material web (22)

y ₂

Distance between nozzle tube (42) and material web (22)

β

angle of attack

Claims (52)

Cooling roller stand (21) for cooling a material web (22) passed through with a plurality of cooling rollers (01; 24), which are partially looped around by the material web (22), characterized in that at least one of the cooling rollers (01; 24) has an insulated cooling roller (01 ) with a cylindrical base body (02) and a heat transfer medium leading outer body (04, 07, 17), wherein the outer body (04, 07, 17) surrounds the base body (02) at least on its lateral surface and wherein the base body (02) and Outer body (04, 07, 17) are thermally insulated from each other. Cooling roller stand (21) according to claim 1, characterized in that the insulated cooling roller (01) is free-running. Cooling roller stand (21) according to claim 1 or 2, characterized in that one or more insulated cooling rollers (01) at the beginning of a web run of the cooling roll stand (21) are arranged. Cooling roller stand (21) according to claim 1, characterized in that all the cooling rollers (01) are formed as insulated cooling rollers (01). Cooling roller stand (21) according to one of claims 1 to 4, characterized in that the outer body (04, 07, 17) of the insulated cooling roller (01) through one or more sleeves (04) with cavities (07) for guiding the heat transfer medium and through a cylindrical outer shell (17) is formed with a chromed outer surface. Chill roll stand (21) according to one of claims 1 to 5, characterized in that the outer surface of the outer body (17) of the isolated Chill roller (01) has a structuring or engraving. Cooling roller stand (21) according to one of claims 1 to 6, characterized in that the insulated cooling roller (01) has a diameter of about 200 mm. Cooling roller stand (21) according to any one of claims 1 to 7, characterized in that in the web run further at least one air knife (29; 31) is arranged, over which the material web (22) passes away. Cooling roller stand (21) according to any one of claims 1 to 8, characterized in that the isolated cooling roller (01) is further assigned a impression roller (26), which by an adjusting device (27) to the isolated cooling roller (01) can be adjusted and / or this is abstellbar, wherein the material web (22) between insulated cooling roller (01) and impression roller (26) is passed. Cooling roller stand (21) according to claim 9, characterized in that the impression roller (26) is deflection compensated. Cooling roller stand (21) according to claim 9 or 10, characterized in that the impression roller (26) is associated with at least one air knife (29, 31). The cooling roll stand (21) according to any one of claims 8 to 11, characterized in that arranged on both sides of the material web (22) is an air knife (29, 31) directed towards the material web (22) so that the two air doctor blades (29; ) with respect to the plane of the web (22). Cooling roller stand (21) according to claim 12, characterized in that a first air knife (29) in the running direction of the material web (22) in front of the isolated Chill roller (01) and a second air knife (31) acts on the other side of the material web (22) and in the running direction of the material web (22) after the insulated cooling roller (01) is arranged. Cooling roller stand (21) according to one of claims 1 to 13, characterized in that between the material web (22) and the insulated cooling roller (01) an electrostatic field is formed. Cooling roller stand (21) according to one of claims 1 to 14, characterized in that there is further provided an electrostatic charging device having two electrodes. Cooling roller stand (21) according to claim 15, characterized in that one of the electrodes rests against the impression roller (26). Cooling roller stand (21) according to claim 16, characterized in that the co-operating with the impression roller (26) cooperating cooling roller (01) forms the other electrode. Cooling roller stand (21) according to claim 17, characterized in that the insulated cooling roller (01) is grounded. Cooling roller stand (21) for cooling a material web (22) guided through with a plurality of cooling rollers (01; 24), which are partially looped around by the material web (22), wherein at least one of the cooling rollers (01; 24) in the cooling roller stand (21). cooperating impression roller (26) is provided, characterized in that between the impression roller (26) and the respective cooling roller (01, 24) an electrostatic field is formed. Cooling roller stand (21) according to claim 19, characterized in that the impression roller (26) can be adjusted by an adjusting device (27) to the respective cooling roller (01; 24) and / or by the respective cooling roller (01; 24). Cooling roller stand (21) according to claim 20, characterized in that the adjusting device (27) by means of an actuator (28) is remote-controlled. Cooling roller stand (21) according to claim 19, characterized in that the impression roller (26) is deflection compensated. Cooling roller stand (21) according to claim 19, characterized in that the pressure roller (26) has two air squeegees (29; 31) associated therewith. The cooling roll stand (21) according to claim 23, characterized in that the two air doctor blades (29; 31) are arranged opposite one another on both sides of the material web (22), the material web (22) being guided between the two air doctor blades (29; A chill roll stand (21) according to claim 23, characterized in that one of the air knife (31) in the running direction of the material web (22) in front of the cooling roll (01; 24) and the air knife (29) acting on the other side of the material web (22) Running direction of the web (22) after the cooling roller (01, 24) are arranged. Cooling roller stand (21) according to claim 19, characterized in that a two-electrode having electrostatic charging device is provided. Cooling roller stand (21) according to claim 26, characterized in that one of the electrodes bears against the impression roller (26). Cooling roller stand (21) according to claim 26, characterized in that the cooling roller (01; 24) cooperating with the impression roller (26) forms the other electrode. Cooling roller stand (21) according to claim 26, characterized in that the cooling roller (01; 24) is grounded. Cooling roller stand (21) according to claim 19, characterized in that the impression roller (26) is supplied with a DC electrical voltage via a spring contact plug. Cooling roller stand (21) according to claim 19, characterized in that on the impression roller (26) the electrical DC voltage is applied without contact with a spaced electrode from him. Chill roll stand (21) according to claim 19, characterized in that at least the cooling roller (01; 24) cooperating with the impression roller (26) acts as an insulated chill roll (01) with a cylindrical base body (02) and an outer body (04, 04) carrying a heat transfer medium. 07, 17) is formed, wherein the outer body (04, 07, 17) surrounds the base body (02) at least on its lateral surface and wherein the base body (02) and outer body (04, 07, 17) are thermally insulated from each other. Cooling roller stand (21) for cooling a material web (22) passed through with a plurality of cooling rollers (01; 24), wherein at least one nozzle tube (41; 42) is provided for minimizing condensate deposits on the cooling rollers (01; first cooling roller (01; 24 - I) is arranged and over the entire width of the cooling roller stator (21) supplied material web (22), wherein the nozzle tube (41; 42) for the flow of a gaseous cooling medium nozzle bores (44) which are aligned substantially opposite to the direction of the web (22), so that the nozzle bores (44) the cooling medium against the direction of the Material web (22) inflate on this. Cooling roller stand (21) according to claim 33, characterized in that the nozzle tube (41; 42) at a vertical distance (y ₁ ; y ₂ ) of 10 mm to 300 mm to the web (22) is arranged. Cooling roller stand (21) according to claim 34, characterized in that the vertical distance (y ₁ ; y ₂ ) between the nozzle tube (11; 12) and material web (01) is 50 to 130 mm. Cooling roller stand (21) according to one of claims 33 to 35, characterized in that a nozzle tube (41; 42) is arranged on each printing side of the material web (22). Cooling roller stand (21) according to claim 36, characterized in that the distance (x ₃ ) of the nozzle tubes (41; 42) in the horizontal direction to each other 100 mm to 300 mm. Cooling roller stand (21) according to claim 37, characterized in that the horizontal distance (x ₃ ) between the nozzle tubes (41; 42) is 150 mm to 200 mm. Cooling roller stand (21) according to one of claims 33 to 36, characterized in that the nozzle tube (41; 42) has a distance of one to two meters to the exit of a hot air dryer (32). Cooling roller stand (21) according to any one of claims 33 to 39, characterized in that the nozzle bores (44) in the nozzle tube (41; 42) have a distance from one another of 30 mm to 150 mm. Cooling roller stand (21) according to claim 40, characterized in that the nozzle bores (44) have a distance of 70 mm to 120 mm from each other. Cooling roller stand (21) according to any one of claims 33 to 41, characterized in that the nozzle bores (44) have a diameter of 0.8 mm to 2 mm. Cooling roller stand (21) according to claim 42, characterized in that the nozzle bores (44) have a diameter of 1 mm to 1.5 mm. Method for cooling at least one material web (22), wherein the at least one material web (22) is passed through a cooling roll stand (21) with a plurality of cooling rolls (01, 24), characterized in that the at least one material web entering the cooling roll stand (21) (22) is acted upon before impinging on a first cooling roller (01; 24) with an air flow which is opposite to the direction of travel of the material web (22) and extends over the entire width of the material web (22). A method according to claim 44, characterized in that the air flow impinges on the material web (22) at an angle of incidence (β) of 15 ° to 60 °. A method according to claim 44 or 45, characterized in that the flow velocity of the air flow is 0.2 to 2 m / s. Method according to one of claims 44 to 46, characterized in that the air flow is directed on both sides of the material web (22). Method according to one of claims 44 to 47, characterized in that the air flow is formed by compressed air. A method according to claim 48, characterized in that the compressed air is directed at a pressure of 3 to 10 bar to the material web (22). Method according to one of claims 44 to 49, characterized in that the air flow has a temperature of 20 ° C to 40 ° C. A method according to claim 44, characterized in that the nozzle tube (41) at a distance (x ₁ ) to a vertical plane with the longitudinal axis of the first cooling roller (01; 24 - I) of less than +/- 100 mm is arranged. A method according to claim 44, characterized in that the nozzle tube (41) at a distance (x ₁ ) to a vertical plane with the longitudinal axis of the first cooling roller (01; 24 - I) of less than +/- 20 mm is arranged.

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