FI106271B - A method for controlling paper curvature and a paper or board machine line employing the method - Google Patents

Description

106271

A method for controlling paper curvature and a paper or board machine line using the method Förfarande för att behärska papperets krullning och en pappers-eller cartonmaskinlinje som tillämpar förfarandet, 5

The invention relates to a method for controlling the curvature of a paper, which method comprises steaming and / or wetting the paper web and / or similar measures for controlling the curvature of the paper web.

The invention also relates to a paper or board machine comprising at least a headbox former, a press and a drying section, wherein the paper or board machine uses steam boxes and / or wetting devices and / or one-sided drying pulses and / or similar curves to control curvature.

As is known in the prior art, multi-cylinder dryers of a papermaking machine utilize a double wire feeder and / or a single wire feeder. In a two-wire delivery, the drying cylinder groups have two wires which press one of the web above and the other below the heated surfaces of the cylinder 20. Between the rows of drying cylinders, generally horizontal rows, there are free and unsupported strokes on the web which are prone to flutter, which can cause web breaks, especially when the web is still relatively damp and consequently weak. As a result, * »more and more recently, there has been an increasing use of said single-wire thread, with each dryer cylinder group having only one dryer wire with support 25 passing through the entire group so that the dryer wire presses the web against side. Thus, in a single-wire delivery, the drying cylinders are outside the wire loop and the turning cylinders or rollers are inside it.

»30 It is known from experience that drying paper one-sided results in a tendency to curl the sheet. When the paper is dried with normal single-wire filament groups on its underside side, and if such asymmetric drying is extended over the entire length of the front dryer section 2 106271, drying occurs first by drying the underside of the paper web and as drying progresses. As a result, the dried paper generally curves from above, concave.

It is already known to influence the tendency of paper to curl in connection with the stripping process, especially in the forming stage, by choosing the difference between the speed of the lip jet and the wire, and the choice of the former and its running parameters. As is known in the art, e.g., by copying paper with one-sided drying, the post-drying section adjusts the initial curvature on the sheet to optimize the paper curvature after one-sided and 10-sided copying. With copy paper, the reactivity of the curl, that is, how much curvature is per unit moisture change, is more influenced by the layered structure of the paper that occurs during stripping at the wet end.

With reference to the prior art relating to the invention, reference is made to Applicant Π Patent No. 91,900 (U.S. Pat. No. 5,416,980), which discloses a method for drying a papermaking machine, in particular to reduce paper curl tendency by drying cylinders against heated surfaces. the paper web is printed with a dryer wire, and wherein the dryer section utilizes dryer cylinder groups 20 where double wire and / or single wire feed is applied. In this process, it has been considered novel that the dryer section feeds hot water vapor to substantially the entire width of the paper web to relieve tensions that are or are expected to occur in the paper web fiber by or substantially immediately thereafter.

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Applicant FI Patent Application 963734 (corresponding to U.S. Provisional Application 60 / 030,693) discloses a method for drying a surface-treated paper web or the like in a paper machine desiccant portion, and a method for drying a paper web in where and that the paper web, during or after drying, is treated with a device (s) 3 106271 to compensate for the tendency of the paper web to curl, such as a steam box, a blower unit, a humidifier and / or a soft calender.

For its part, Applicant Fl Publication No. 98,387 (corresponding to U.S. Patent Application No. 08 / 705,059) 5 discloses a process for producing surface-treated paper, in particular fine paper, and a dry end for a papermaking machine. Compressing the dried paper web is dried in a front drying section, wherein the paper web is subjected to drying energy over the entire length of the front drying section in the z direction asymmetrically from the underside of the web. Em. the step is performed by several successive downwardly open individual wire export groups in support of the dryer wire. Thus, both machine and transverse shrinkage of the web as the content of dry matter increases are essentially prevented. In the event of a web break, the paper wreck is removed downwardly underneath the open drying groups, mainly to the gravity below the wreck conveyor. Because of the asymmetric pre-drying, the curled paper web is led to a post-treatment section, where it is post-treated with wetting and / or plastic modification so as to eliminate the curling tendencies created during the pre-drying step. Examples include dual wire feed groups and steam control in the after-drying section, as well as steam boxes and infra- and fluidized drying placed to control curvature.

Applicant FI Patent Application 964830 (corresponding to U.S. Provisional Application No. 60 / 032,405) discloses a method for drying paper and a dry end of a papermaking machine. The method i for drying paper comprises the steps of: drying a web of paper from a press section to a front drying section wherein the paper web is dried from its underside side in drying groups employing normal single-wire dyeing; drying in a post-drying section where the paper web is - dried in at least one drying group employing normal single-wire export, then the paper web is calendered on a calendar and fed to a winding station where 30 paper webs and / or in the region of the post-treatment section the dry end of the aperic machine, in turn, comprises a pre-drying section and a post-processing section which comprises a coating / surface sizing apparatus, a post-drying section, a calender and a winding station. The dry end of the papermaking machine comprises elements and / or combinations of said elements 5 and combinations for controlling the curvature of the paper web in the area of the pre-drying section and / or post-treatment section. Elements for curvature control include e.g. blowing hot humidified air through a wire for use with a front drying section, a steam box for use with a after drying section, a combination of steaming in a steam box with a cooling cylinder; against the web with the post-drying section, the infrared boxes before the calender, transferring the moist air from the front drying section to the post-drying section for blowing into the web, and with the iron by mechanical shaping of the web.

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Reference is also made, in the prior art, to U.S. Patent No. 5,557,860, which discloses a drying section made of drying groups employing normal single-wire export and a wetting device positioned after the drying groups to control curvature.

20th It is also known in the art to humidify the surrounding air of the winder, thereby preventing the paper from drying and shrinking in the winder. Too low relative humidity of the ambient air in the winder will result in uncontrolled drying and shrinkage of the paper, which in turn will cause the paper to break at the knives 25 and make it difficult to cut as well as to make joints. In too dry conditions, it may also be difficult to meet the roll accuracy requirements.

'' This known humidification system comprises humidifying nozzles and air devices mounted below the winder. These are used to humidify the rising air on the winder and direct it to the knife under controlled conditions. The humidity level can be adjusted steplessly by 30 masts. Thus, this known solution does not attempt to control the curvature of the paper.

»« 5 106271

In the prior art solutions described above, the curvature adjusting devices and the like are disposed on the dry end of the paper machine before the calender. It is hypothesized that curvature adjustment operations performed after the calender will adversely affect the surface properties of the paper. However, the disadvantage of the curl adjusting device 5, such as a steam box or humidifier, placed before the calender, is that it also strongly affects the calendering result, i.e. the smoothness of the surfaces and the sweat of the paper. This often prevents complete control of the curvature. The efficiency of the humidifying / steaming device located on the drying section again suffers from the high temperature of the web. Devices to be placed inside the dryer section hood also need to be designed considering the hot and humid environment. Any maintenance work must also be scheduled for downtime.

Prior to the calender, the curvature adjusting devices shall be located near the end of the drying section, with the temperature of the web and the ambient air being highest. In this case, for example, the use of a steam board-15 needle is not very effective (without cooling the web), since the steam does not condense on a hot (70-80 ° C) web and thus balances the 2-way moisture profile. When using web cooling, for example, cooling cylinders, the length of the drying section is increased, which is not economically meaningful. In addition, larger amounts of steam or water are required at the end of the drying section due to the hot web to rectify the 2-way moisture profile.

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It is therefore an object of the present invention to approach the problems of curvature control from a new perspective and to provide new solutions to these in the face of conventional thought processes.

It is an object of the present invention to provide a method for controlling curvature and a paper or board machine in which the steps required to control and adjust the curvature can be performed after the calender.

In order to achieve the foregoing and subsequently disclosed objectives, the process of the invention is essentially characterized in that the process for controlling the curvature of the paper web is carried out in connection with existing process steps or web exports in a papermaking process, or in the process steps carried out in connection with or after its web entries or their web entries.

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The paper or board machine according to the invention, for its part, is essentially characterized in that the steam boxes and / or humidifying devices and / or IR driers and / or corresponding curvature control devices for controlling the curvature of the paper web are disposed in , in connection with the machine reel or its web inlets or the subsequent post-processing process or its web inputs.

According to the invention, the curvature is adjusted after the calendering process by means of a steam box or humidifier or other similar curvature control arrangement known per se, e.g. in connection with a winder, a winder, an intermediate calender, a popper, etc. The operations required to adjust the curvature may be carried out, for example, by steam blasting with the reel, rotating the reel with the unwinder, providing the curl adjustment effect with e.g. an infrared heater or similar device for drying the web from one side.

With these new arrangements, you can influence the curvature of the paper path and adjust it as desired. Because curvature control operations are only performed after the calender, the advantage is that curvature control is performed as close to the end product as possible and that the effect of all prior process factors can be effectively accounted for. The web temperature is also quite low, whereby the effect of steaming is effective. In addition, the devices can be positioned so that they can be serviced at least partially even when the machine is running. Also, the curvature adjustment performed after the calender, e.g., one-sided steaming, does not affect the calendering process and thus causes differences in the upper product between the upper and lower surfaces, e.g., roughness gloss.

*

According to the invention, the operations to control the curvature are performed on either or both sides of the web.

In the following, the invention will be described in more detail with reference to the figures in the accompanying drawings, the details of which, however, are not intended to be limited in any way.

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Fig. 1 schematically illustrates an embodiment of the invention for controlling curvature in a roller.

Fig. 2 schematically illustrates an embodiment of the invention for controlling curvature 15 in connection with an unwinding roller.

Fig. 3 schematically illustrates an embodiment of the invention for controlling curvature after a calendering process in which a steam box is provided before the roller to control curvature.

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Fig. 4 schematically illustrates an embodiment of the invention for controlling curvature after a calendering process in which two steam boxes are provided before the roller to control curvature.

Fig. 5 schematically illustrates an embodiment of the invention in which a steam box is placed before the roll and in connection with the roll of paper formed by the roll to control the curvature.

Fig. 6 schematically shows an embodiment of the invention in which two steam boxes are arranged in connection with a roll of paper formed by a roller for controlling the curvature 30.

106271 8

Fig. 7 schematically shows an embodiment of the invention for controlling the curvature after the calendering process, in which both the wetting device and the steam device before the roller are located to control the curvature.

Fig. 8 schematically shows an exemplary embodiment of the invention in which a wetting device is placed before the roller to control curvature.

Fig. 9 schematically shows an embodiment of the invention in which two wetting devices are placed before the roller to control the curvature.

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Fig. 10 schematically illustrates an embodiment of the invention in which the curvature control means are disposed within a supercalender.

In the schematic embodiment of the invention shown in Figure 1, to control curvature after the calender, the web W is rolled from roll 27 through rolls 22,23,24,25,26 to roll 21 with roller bodies generally designated 28 and in the reel warehouse. Empty reel irons with reference numeral 29. Figure 1 illustrates various possible alternatives for positioning the curvature control in connection with the reel 20. For example, below the winding nip N of the roller 21 and the roller-20 web 22, a steam blasting box 22A or similar device may be disposed, showing a partial magnification at A indicating that the steam blowing box 22A or similar source may blow steam blowing into blowing per roll surface 21 Pl. According to further alternatives, a steam blasting box 25 or a similar device 25A, 26A may be provided in connection with the control / guide rolls 25,26.

In the schematic embodiment of the invention shown in Fig. 2, the paper web W is unwound in the unrolling station 60 from the roll 61 and the web W is guided through the rolls 62,63,64 to the winder 65 from which it is further guided through the rolls 66,67 to Supported by 68 and 69 and in connection with winding, a printing roller 72 is also used. Reference numeral 73 denotes 106271 9 roller feeders. Various devices for controlling curvature can be provided in conjunction with such a device configuration to control curvature. For example, steam blasting boxes 63A.66A or equivalent% devices may be provided in connection with guide roller 63 and / or 66. A steam box 5 68A may be provided in connection with the roller 70, or a steam roller may be formed from the second roller 69 to form a vapor discharge zone 69A or a steam tube 71A may be provided in the space between the rollers 68,69 and the resulting paper roll 71. If necessary, in the unwinding step, the paper roll 61 can be rotated to obtain the effect of curl adjustment on one side of the paper web W.

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The applications shown in Figures 3-9 show the last two single-threaded export groups R 1 ^ of the dry end of the papermaking machine, the group intervals of which are closed for export on web W. In the figures, the machine direction, i.e. the direction of travel of the web W, is indicated by the arrow S. The single-wire groups R1, R2 are so-called normal groups, for example steam-heated smooth-drying 15 cylinders 10 in upper rows and pivoting suction cylinders 11 in lower rows. Each of the drying groups R1, R2 has its own drying wire 15 which is guided by the guide rolls 18. The drying webs 15 press the web W to be dried with their drying cylinders 10 against their smooth heated surface, and with the turning cylinders 11, the web W remains on the outside of the outer surface of the web 15. In the turning cylinders 11, the web W is held securely against the effect of centrifugal forces in the support of the wire 15 by the negative pressure prevailing on the groove surface of the turning cylinders 11 or the corresponding diaphragm of the suction roll, which also prevents transverse shrinkage of the web. Especially preferred are rotary actuation cylinders 11, without the internal suction box, marketed by the applicant under the trademark VacRoll ™, the details of the structures of which refer to Applicant's FI Patent No. 83680 (U.S. Pat. Nos. 5,022,163 and 5,172,491). The support contact between the web W and the drying fabric 15 is also considered to be correct in the direct spacing between the drying cylinders 10 and the turning cylinders 11 by using at least runs from the drying cylinders 10 to the turning cylinders 11, which also prevents Blowing simulation 17 refers to blowing boxes whose air blowing causes 106271 10 and these boxes 17 are not connected to vacuum sources. For details of the structures of these blowing simulations 17, which are marketed by the applicant under the trademark "UnoRun BlowBox" ^^, reference is made to the applicant's FI patents Nos. 59637, 65460 and 80491 (U.S. Pat. Nos. 4,441,263, 4,516,330 and 4,905,380). Known blower box solutions are within the scope of the overall concept of the present invention.In single-wire groups R1, R2, blower boxes 16 are also used between the rotating cylinders 11 to ventilate these intermediate spaces and promote evaporation from the dough W. The surfaces of the drying cylinders 10 are clean.

In addition, in the embodiments shown in Figures 3-9 of the invention, the post-treatment part includes a machine reel 50, such as a pop reel. An on-line reel of 50 machine reels is shown as MRq and one finished machine reel is referred to as MR. To machine reel 50, web W is fed through calender 40 from post-drying section 30 via guide and guide rolls 35,45,46,47. After the last guide / guide roll 47, a measuring device 48 is placed on the web W

15 to measure properties before rolling. Calender 40 may preferably be so-called calender. soft calender with one roll heated and the other soft coated. Of course, the calender can also consist of two hard rolls. There may also be several calender nipples.

In Figure 3, to control the curvature, a steam box 81 is provided for the run of web W between the guide / guide rollers 46.47, so that the curvature is affected when the calendering process takes place before the roller 50. If the curvature tendency is effectively controlled in both directions, box 81A or equivalent.

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Fig. 4 shows a steam box 82 disposed between the guide / guide rollers 45 and 46 and a steam box 81 for the web run between the guide / guide rolls 46,47, both of which affect curvature control as the web W runs between the calender 40 and the reel 50.

30 106271 11

In Fig. 5, in addition to the steam box 81 arranged on the portion between the guide / guide rollers 46,47, a steam box 83 is provided in connection with the paper roll MRq formed, in addition to the web flow between the calender 40 and roller 50 A mobile steam box 83 is provided adjacent the MRq of the 5 rolls formed, as indicated by the arrow Sg3- The box 83 is moved as the roll size increases as the roll progresses.

In Fig. 6, two steam boxes 83.84 are provided in connection with the forming roll MRq, both of which are movable Sg3, Sg ^ as the roll size increases as the roll 10 advances. Of course, a steam or humidifying device 8IA placed above the web can of course also be used to provide upper curvature adjustment.

In Fig. 7, in addition to the steam box 81 provided for the web W running between the guide / guide rollers 46,47, a web W humidifier 85 is provided for the web W running between the guide / guide rollers 45,46 15 whereby the curvature of the web W that steaming.

Fig. 8 provides a wetting device 86 for controlling the curvature of the web W between the guide / guide rollers 46,47 after the calender 40. Fig. 20 also shows an IR drier 87 for applying a thermal energy impulse to the upper surface of the web. Instead of IR drying, another drier device may be used. Similarly. the equipment may be located on either side of the track. Controlling the curvature by means of additional drying on one side can be used either alone or in combination with a steaming and / or humidifying device.

25 to 9 • In the exemplary embodiment shown in Fig. 9, wetting devices 85,86 are provided for the web W runs between the control / guide rollers 45,46 and 46,47 to control the curvature of the web W after calendering prior to winder 50. Of course, one wetting device may also be used. located on opposite sides of web 30.

106271 12

In the exemplary embodiment shown in Fig. 10, curve adjustment is performed in conjunction with supercalender 110. The web W passes from the unwinder 100 to the top of the super calender 110 and further from the lower part of the super calender 110 to the rewinder 120. The super calender 110 consists of a vertical roll stack where the polishing nipples of the web W consist of a hard surface and a soft surface roll. The figure indicates a few possible positions (91,92,93,94,95,96) in which steam boxes and / or wetting devices and / or high surface heating devices may be used. The devices may thus be located on the web W run (91.92) between the unwind roll 100 and the super calender 110 and / or in connection with the output rollers 111 on the super calender 110 (93.94) and / or the web W run (95) between the , 96).

The invention has been described above with reference only to some preferred embodiments thereof, the details of which, however, are not to be construed in any way narrowly limited. The features shown in various embodiments of the invention can be combined in many different ways to control the curvature. Of course, according to the invention, other arrangements known per se for controlling curvature can be used after the calendering process. Many modifications and variations are possible within the scope of the inventive idea defined in the following claims.

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Claims (34)

1. A method for controlling the curia of paper, wherein method is used for angling the paper web (W) and / or wetting and / or similar measures for controlling the curia of the paper web (W), characterized in that the performed in the procedure for mastering the curry of the paper web (W) is performed in conjunction with the process stages and web transfers that occur in the paper making line after a calendering process performed in a calender (40) or in processes where no calendering is used, in connection with a machine wheelchair 10 or its path transfers or in the process stages or their path transfers performed thereafter. 2. A method according to claim 1, characterized in that the paper web (W) is steamed or wetted in the process with a scaffold / scaffold (22A.22B) or wetting means arranged in connection with a rolling roller (22) in a roll-out chair (20). . Method according to Claim 1 or 2, characterized in that the paper web (W) is steamed or wetted in the process with an angled / angled (25A, 26A) or wetting means arranged in conjunction with guide / guide rollers (25, 26) in the roll-out. 20 the chair (20). Method according to claim 1, characterized in that the paper web (W) is steamed or wetted in the process after a roll-out chair (60) with a meadow / meadow (63A, 66A) or wetting means arranged in connection with guide / guide rollers (63,66). ) Located before and / or after a longitudinal cutting machine (65). 5. A method according to claim 1 or 4, characterized in that the paper web (W) is steamed or wetted in the process with an angel bed (68A) or wetting devices arranged in connection with one of the supporting rollers (68) of a wheelchair (70) in a carrier rolling wheelchair. and / or with an angling zone (69A) formed in the second carrier roll (69) and / or by the grinding of a single tube (71A) arranged between the carrier roll area (68,69) and the paper roll (71) being formed. * 6. A method according to claim 1, characterized in that the paper web (W) is steamed in the process after a calender (40) having at least one angel bed (81) before a wheelchair (50). 7. A method according to claim 1, characterized in that the paper web (W) is angled with two angel wings (81.82) on a web race between a calender (40) and a wheelchair 10 (50). Method according to Claim 1 or 6-7, characterized in that the paper web (W) is steamed or wetted in the process with an angel bed (83) or wetting devices arranged in connection with the paper roll (MRq) formed with the wheelchair 15 (50). . 9. A method according to claim 8, characterized in that the angel bed (83) or the corresponding wetting device (S33) arranged in conjunction with the roll (MRq) formed during formation is displaced (S33) during the rolling of the roll. m Method according to claim 1, characterized in that the paper web (W) is steamed during the process with two angel beds (83,84) or corresponding wetting devices arranged in connection with the paper roll (MRq) formed by a wheelchair (50) which is moved (Sg3, Sg4) as the roll progresses. 25 11. A method according to claim 1, characterized in that the paper web (W) in the process is moistened with a wetting device (85) and angled with an angel bed (81) on a web run between a calender (40) and a wheelchair (50). 106271 20 Method according to claim 1, characterized in that the paper web (W) in the process is wetted with at least one wetting device (86) on a web between a calender (40) and a wheelchair (50). 5 Method according to claim 1, characterized in that the control of the curia in the method is carried out with a one-sided drying pulse directed towards the web. Method according to claim 13, characterized in that the one-sided drying pulse is effected by one or more IR dryers. 10 15. A method according to claim 13, characterized in that the one-sided drying is used in conjunction with angling and / or wetting. A method according to any of the preceding claims, characterized in that measures for controlling the curry of the paper web (W) are carried out in the process when the web (W) has been dried in at least two drying groups (R drying portion (30). A paper or cardboard machine, comprising at least one inlet carriage, a former, a press and a drying portion, in which the paper or cardboard machine is used for controlling: by curia angels and / or wetting devices and / or an IR dryer and / or similar devices for controlling the curia, characterized in that the angelic lids and / or wetting devices and / or IR dryers and / or similar devices for controlling the curia are located for controlling the curia of the paper web (W), in connection with the process - the stages or web transfers that occur in the paper making line, after a calender (40) or if a calender is not used, in connection with a machine wheelchair or its web transfers or in connection with a finishing process or its web transfers after that. 18. A paper or cardboard machine according to claim 17, characterized in that the paper or cardboard machine comprises an angel-bed / angel-bed (22A, 22B) or wetting means arranged in conjunction with a rolling roller (22) in a roll-out chair (20). A paper or cardboard machine according to claim 17 or 18, characterized in that the paper or cardboard machine comprises an angled / angled (25A, 26A) or wetting device arranged in conjunction with guide / guide rollers (25, 26) in a wheelchair (20). 20. A paper or cardboard machine according to claim 17, characterized in that the paper or cardboard machine comprises an angled / angled (63A.66A) or wetting device arranged in conjunction with guide / guide rollers (63,66) located after a roll-out chair (60 ) before and / or after a longitudinal cutting machine (65). A paper or cardboard machine according to claim 17 or 20, characterized in that the paper or cardboard machine comprises an angel bed (68A) or a wetting device arranged in connection with one support roll (68) of a wheelchair (70) in a wheelchair (70). carrier roll wheelchair and / or an angling zone (69A) formed in the second carrier roll (69) and / or a meadow tube (7IA) arranged between the support rollers (68,69) and the forming roll (71). 20 A paper or cardboard machine according to claim 17, characterized in that the paper or cardboard machine comprises, after a calender (40), at least one meadow (81) before a wheelchair (50). Paper or cardboard machine according to claim 17, characterized in that two meadow beds (81.82) are located in the paper or cardboard machine on a track between a calender (40) and a wheelchair (50). A paper or cardboard machine according to claim 17, characterized in that the paper or cardboard machine comprises an angel bed (83) or a wetting device arranged in connection with the paper roll (MRq) formed with the wheelchair (50). 22 106271 25. A paper or cardboard machine according to claim 24, characterized in that the angular bed (83) or wetting device (Sg3) arranged in conjunction with the roll (MRq) formed in the formation is movable (Sg3) as the roll is advanced. Paper or cardboard machine according to claim 17, characterized in that the paper or cardboard machine comprises two meadow beds (83,84) or wetting devices arranged in connection with the paper roll (MRq) formed by the wheelchair (50), which are movable ( Sg3, Sg4)) as the scroll progresses. A paper or cardboard machine according to claim 17, characterized in that the paper or cardboard machine comprises a wetting device (85) and a meadow (81) on a runway between a calender (40) and a wheelchair (50). A paper or cardboard machine according to claim 17, characterized in that the paper or cardboard machine comprises at least one wetting device (86) on a runway between a calender (40) and a wheelchair (50). Paper or cardboard machine according to claim 17, characterized in that a calender (40) is used as a calender. 20 30. A paper or cardboard machine according to claim 17, characterized in that the calender is formed by hard surface rollers. Paper or cardboard machine according to claim 30, characterized in that a calender (40) is used as a calender. A paper or cardboard machine according to claim 31, characterized in that the control of the curry is carried out with humidifying / grazing / heating devices (91,92,93,94,95,96) located at supercalender. 30 33. A paper or cardboard machine according to claim 17, characterized in that the paper or cardboard machine comprises an after-drying portion (30) which exhibits at least two drying groups (R 1, R 2) which apply normal single wire routing. 34. A paper or cardboard machine according to claim 17, characterized in that the device (s) for controlling the curry is profiling in the transverse direction of the machine.