Abstract:
The invention relates to a corrugated cardboard installation. The corrugated cardboard installation comprises a first material supply device for dispensing a first material web, a second material supply device for dispensing a second material web, a first corrugated cardboard production assembly for producing a first corrugated cardboard web from the first material web and the second material web, a cross-cutting assembly for producing corrugated cardboard sheets from the first corrugated cardboard web, a warp detection assembly for detecting the warp of corrugated cardboard sheets or partial corrugated cardboard webs, an information processing device receiving warp information from the warp detection assembly relating to the corrugated cardboard sheets or the partial corrugated cardboard webs, and at least one corrugated cardboard sheet warp influencing assembly (actuable depending on signals received from the information processing device for influencing the warp of the corrugated cardboard sheets.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of German Patent Application, Serial No. 10 2014 202 537.0, filed Feb. 12, 2014, pursuant to 35 U.S.C. 119(a)-(d), the content of which is incorporated herein by reference in its entirety as if fully set forth herein. 
       FIELD OF THE INVENTION 
       [0002]    The invention relates to a corrugated cardboard installation for the production of corrugated cardboard sheets. The invention further relates to a method for the production of corrugated cardboard sheets in a corrugated cardboard installation. 
       BACKGROUND OF THE INVENTION 
       [0003]    Corrugated cardboard installations for the production of corrugated cardboard sheets are generally known from prior art through prior public use. The corrugated cardboard sheets are produced from endless corrugated cardboard webs or from partial corrugated cardboard webs which are in turn produced from the endless corrugated cardboard webs. A common problem in the production of corrugated cardboard webs is that the corrugated cardboard webs are warped or curved after production thereof. This is generally due to an incorrect setting of the corrugated cardboard installation, defects in the corrugated cardboard installation and/or a poor quality of the raw materials used, such as the raw paper. Corrugated cardboard sheets warped in this manner are often unsuitable for further use. 
       SUMMARY OF THE INVENTION 
       [0004]    An object of the invention is therefore to provide a corrugated cardboard installation for the production of corrugated cardboard sheets which is able to overcome the drawbacks set out above. In particular, the object of the invention is to provide a corrugated cardboard installation for the production of corrugated cardboard sheets that have a desired warp or plane shape while further allowing deviations from said desired warp or said desired plane shape of the corrugated cardboard sheets to be detected as early as possible in the production of said corrugated cardboard sheets. Another object of the invention is to provide a corresponding method for producing corrugated cardboard sheets. 
         [0005]    According to the invention, this object is achieved by a corrugated cardboard installation for the production of corrugated cardboard sheets, comprising a first material supply device for dispensing a first material web, a second material supply device for dispensing a second material web, a first corrugated cardboard production device for producing a first corrugated cardboard web laminated on at least one side from at least the first material web and the second material web, a cross-cutting assembly for producing corrugated cardboard sheets from at least the first corrugated cardboard web laminated on at least one side, a warp detection assembly for detecting a warp of the corrugated cardboard sheets and/or of partial corrugated cardboard webs produced at least from the first corrugated cardboard web laminated on at least one side, an information processing device which receives from the warp detection assembly warp information relating to the corrugated cardboard sheets and/or the partial corrugated cardboard webs, and at least one corrugated cardboard sheet warp influencing assembly for influencing the warp of the corrugated cardboard sheets, wherein the at least one corrugated cardboard sheet warp influencing assembly is actuable depending on the signals received from the information processing device, and by a method for the production of corrugated cardboard sheets, comprising the steps of dispensing a first material web from a first material supply device, dispensing a second material web from a second material supply device, producing, by means of a first corrugated cardboard production assembly, a first corrugated cardboard web laminated on at least one side from at least the first material web and the second material web, producing corrugated cardboard sheets from at least the first corrugated cardboard web laminated on at least one side by means of a cross-cutting assembly, detecting a warp of the corrugated cardboard sheets and/or of partial corrugated cardboard webs from at least the first corrugated cardboard web laminated on at least one side by means of a warp detection assembly, transmitting warp information relating to the corrugated cardboard sheets and/or the partial corrugated cardboard webs from the warp detection assembly to an information processing device, and influencing the warp of the corrugated cardboard sheets depending on signals received from the information processing device by means of at least one actuable corrugated cardboard sheet warp influencing assembly. The gist of the invention is that a warp detection device detects a warp of the corrugated cardboard sheets and/or partial corrugated cardboard webs. The warp of the corrugated cardboard sheets is influenceable, in particular regulable, by means of at least one corrugated cardboard sheet warp influencing assembly in such a way that the corrugated cardboard sheets have a desired warp or follow a desired path along their length and/or width as defined by warp information relating to the corrugated cardboard sheets and/or partial corrugated cardboard webs. 
         [0006]    The first material supply device is preferably configured as a splicer. 
         [0007]    It is advantageous if the second material supply device is configured as a splicer as well. 
         [0008]    The cross-cutting device advantageously comprises at least one knife roller with at least one knife for cross-cutting at least the first corrugated cardboard web laminated on at least one side. 
         [0009]    Preferably, an endless corrugated cardboard web, which is or comprises the first corrugated cardboard web, is cut and divided into a number of partial corrugated cardboard webs. It is advantageous if each partial corrugated cardboard web is associated to at least one knife roller with at least one knife for cross-cutting the respective corrugated cardboard web. It is advantageous if a longitudinal cutting and corrugating assembly is provided to produce the partial corrugated cardboard webs from at least the first and second material webs. 
         [0010]    The warp detection device is in particular able to detect whether the corrugated cardboard sheets and/or the partial corrugated cardboard webs are at least partially warped or non-warped along the length and/or width thereof. 
         [0011]    Advantageously, the warp detection device is contactless. The warp detection device detects for instance the respective distance from the respective corrugated cardboard sheet or from the respective partial corrugated cardboard web across the entire width and/or length thereof. Alternatively, the warp detection device preferably detects the profile of the entire respective corrugated cardboard sheet or of the entire respective partial corrugated cardboard web. In a particularly preferred embodiment, the warp detection device is configured as a laser distance detection device or as a line profile detection device. 
         [0012]    It is expedient if the warp detection device is immovable at least in a transport direction of the web or corrugated cardboard sheets. 
         [0013]    It is advantageous if the information processing device is an electronic information processing device. 
         [0014]    Preferably, several corrugated cardboard sheet warp influencing assemblies are provided. It is advantageous if the information processing device sends actuating signals to at least one of the corrugated cardboard sheet warp influencing assemblies to influence the warp of the corrugated cardboard sheets. 
         [0015]    When it is necessary to influence the warp of the corrugated cardboard sheets, it is advantageous if at least one, preferably more than one, more preferably all of the corrugated cardboard sheet warp influencing assemblies influence the warp of the corrugated cardboard sheets in and/or transverse to the transport direction thereof. 
         [0016]    The warp of the corrugated cardboard sheets is influenceable for instance by changing the moisture and/or temperature on one side of at least one material web or at least one corrugated cardboard web. 
         [0017]    It is expedient if a wireless or wired signal communication is provided between the information processing device and the at least one corrugated cardboard sheet warp influencing assembly. 
         [0018]    Advantageously, a wireless or wired signal communication is provided between the warp detection device and the information processing device. 
         [0019]    It is advantageous if the first preheating assembly, which serves as a first corrugated cardboard sheet warp influencing assembly for influencing the warp of the corrugated cardboard sheets by preheating the first material web on one side, is arranged between the first material supply device and the first corrugated cardboard production assembly, said first corrugated cardboard sheet warp influencing assembly being associated to the first material web, and comprises a first preheating roller which is partly in contact with the first material web. The first material web is thus preheated at least partly across the thickness thereof from the side which is in contact with the first preheating roller. The preheating temperature of the first preheating roller is changeable by means of the information processing device, which results in a changed warp of the corrugated cardboard sheets. When said preheating temperature is increased, this causes the corrugated cardboard sheets to warp downwardly, thus resulting in a so-called down-warp. 
         [0020]    The second corrugated cardboard sheet warp influencing assembly of the first corrugated cardboard production assembly is configured as a glue application assembly for applying glue to one side of the first material web and/or the second material web, wherein allows the layer of glue applied to the first and/or second material web to be changed by means of the information processing device which changes an application of glue to the first material web and/or the second material web by means of the glue application assembly in order to influence the warp of the corrugated cardboard sheets, which results in a changed warp of the corrugated cardboard sheets. In particular, the amount of glue applied thereto is changeable. Alternatively, the composition, in particular the moisture, of the glue is changeable. It is advantageous if the glue application device comprises a glue application roller which applies glue to the side of the respective material web abutting against said glue application roller. By changing the position of the glue application roller relative to said material web, it is for instance possible to easily change the amount of glue applied to said material web, which in turn influences the moisture of said material web. When the moisture in the second material web is increased, this causes the corrugated cardboard sheets to be warped upwardly, thus resulting in a so-called up-warp. 
         [0021]    The third material supply device set out for dispensing a third material web is preferably configured as a splicer. 
         [0022]    It is advantageous if the fourth material supply device is configured as a splicer. 
         [0023]    It is conceivable for the first corrugated cardboard web and the second corrugated cardboard web to be joined, more preferably glued, to each other preferably in the manner of layers. Preferably, another cover layer can be joined, more preferably glued, to a free corrugated web of the first or second corrugated cardboard web. 
         [0024]    It is advantageous if a third corrugated cardboard sheet warp influencing assembly, configured as a second preheating assembly for influencing the warp of the corrugated cardboard sheets by preheating the third material web on one side, is arranged between the third material supply device and the second corrugated cardboard production assembly, said third corrugated cardboard sheet warp influencing assembly comprising a second preheating roller which is partly in contact with the third material web. The third material web is thus preheated at least partly across the thickness thereof from the side which is in contact with the second preheating roller. The preheating temperature of the second preheating roller is changeable by means of the information processing device, which results in a changed warp of the corrugated cardboard sheets. When said preheating temperature is increased, this causes the corrugated cardboard sheets to warp downwardly, thus resulting in a so-called down-warp. 
         [0025]    The fourth corrugated cardboard sheet warp influencing assembly is configured as a glue application assembly of the second corrugated cardboard production assembly for applying glue to one side of the third material web and/or the fourth material web, thus allowing the layer of glue applied to the third and/or fourth material web to be changed by means of the information processing device which changes an application of glue to the third material web and/or the fourth material web by means of the glue application assembly, thus resulting in a changed warp of the corrugated cardboard sheets. In particular, the amount of glue applied thereto is changeable. Alternatively, the composition, in particular the moisture, of the glue is changeable. It is advantageous if the glue application assembly comprises a glue application roller which applies glue to the side of the respective material web abutting against said glue application roller. By changing the position of the glue application roller relative to said material web, it is for instance possible to easily change the amount of glue applied to said material web, which in turn influences the moisture of said material web. When the moisture in the fourth material web is increased, this causes the corrugated cardboard sheets to be warped upwardly, thus resulting in a so-called up-warp. 
         [0026]    Preferably, the fifth corrugated cardboard sheet warp influencing assembly configured as a preheating assembly for preheating a respective side of at least the first corrugated cardboard web and the second corrugated cardboard web from in each case one side in order to influence the warp of the corrugated cardboard sheets has a preheating roller associated to the first corrugated cardboard web, wherein the first corrugated cardboard web partly abuts against the outside thereof so as to be preheated from its side abutting against said preheating roller. 
         [0027]    Advantageously, the preheating assembly has another preheating roller associated to the second corrugated cardboard web, wherein the second corrugated cardboard web partly abuts against the outside thereof so as to be preheated from its side abutting against said preheating roller. 
         [0028]    It is expedient if the preheating assembly comprises another preheating roller associated to a cover layer, wherein said cover layer partly abuts against the outside thereof so as to be preheated from its side abutting against said preheating roller. 
         [0029]    The preheating temperature of the preheating assembly is changeable for the first corrugated cardboard web, the second corrugated cardboard web and/or the cover layer, which results in a changed warp of the corrugated cardboard sheets. Preferably, the preheating temperature of at least one, more preferably of all preheating rollers of the preheating assembly is changeable, which results in a changed warp of the corrugated cardboard sheets. When the preheating temperature for the first corrugated cardboard web is increased, this causes the corrugated cardboard sheets to be warped downwardly, thus resulting in a down-warp. When the preheating temperature for the cover layer is increased, this causes the corrugated cardboard sheets to be warped upwardly, thus resulting in an up-warp. 
         [0030]    Preferably, the sixth corrugated cardboard sheet warp influencing assembly, configured as a glue application assembly for applying glue to a respective side of the first corrugated cardboard web and the second corrugated cardboard web in order to influence the warp of the corrugated cardboard sheets, has a first glue application device associated to the first corrugated cardboard web, allowing glue to be applied to said first corrugated cardboard web. 
         [0031]    Advantageously, the glue application assembly has a second glue application device associated to the second corrugated cardboard web, allowing glue to be applied to said second corrugated cardboard web. 
         [0032]    The layer of glue applied to the first and/or second material web is changeable, thus causing the warp of the corrugated cardboard sheets to change. In particular, the amount of glue applied thereto is changeable. Alternatively, the composition, in particular the moisture, of the glue is changeable. It is advantageous if the first glue application device comprises a first glue application roller which applies glue to the side of the respective material web abutting against said glue application roller. Advantageously, the second glue application device has a second glue application roller which applies glue to the side of the respective material web abutting against said glue application roller. By changing the position of the first and/or second glue application roller relative to the associated corrugated cardboard web, it is for instance possible to easily change the amount of glue applied to said corrugated cardboard web, which in turn influences the moisture in said material web. When the moisture in the first corrugated cardboard web is increased, this causes the corrugated cardboard sheets to be warped upwardly, thus resulting in a so-called up-warp. When the moisture in the second corrugated cardboard web is increased, this causes the corrugated cardboard sheets to be warped downwardly, thus resulting in a so-called down-warp. 
         [0033]    It is advantageous if the seventh corrugated cardboard sheet warp influencing assembly, configured as a heating and pressing assembly for pressing together the first corrugated cardboard web, the second corrugated cardboard web and a cover web, and for heating at least one of them on one side in order to influence the warp of the corrugated cardboard sheets cardboard sheets, comprises at least one heating member the heating temperature of which is changeable by means of the information processing device. The at least one heating member allows the entire corrugated cardboard web to be heated. When the heating temperature of the at least one heating member is changed, this causes the warp of the corrugated cardboard sheets to change. The at least one heating member is arranged adjacent to the outer corrugated cardboard web and/or the cover layer. Preferably, it is only adjacent to the cover layer. When the heating temperature for the cover layer is changed, this causes the corrugated cardboard sheets to be warped upwardly, thus resulting in an up-warp. 
         [0034]    Preferably, the heating and pressing assembly has at least one pressure member which is in particular configured as a rotating pressure belt that is preferably in a pressing engagement with the first corrugated cardboard web. The at least one pressing member preferably allows the moisture in the first corrugated cardboard web to be changed alternatively or in addition to the heating temperature change performed by the at least one heating member, thus allowing the warp of the corrugated cardboard sheets to be influenced as well. When the moisture in the first corrugated cardboard web is increased by means of the first pressure member, this causes the corrugated cardboard sheets to be warped upwardly, thus resulting in an up-warp. It is advantageous if the at least one pressure member allows steam or liquid to be applied to the first corrugated cardboard web, preferably by spraying. It is expedient if at least one, more preferably a plurality of outlet openings are formed in the at least one pressure member, said outlet openings allowing said liquid or steam to be transported to the first corrugated cardboard web. 
         [0035]    As a general rule, it shall be noted that when the corrugated cardboard sheet warp influencing assemblies are operated inversely to the mode of operation set out above, in other words the preheating temperature or the moisture in the web is reduced, this results in a corresponding inverse warp of the corrugated cardboard sheets. 
         [0036]    The degree of actuation of the corrugated cardboard sheet warp influencing assemblies allows one to influence the degree of the warp of the corrugated cardboard sheets. 
         [0037]    When several corrugated cardboard sheet warp influencing assemblies having the same influence on the warp behaviour of the corrugated cardboard sheets are operated at the same time, this allows the corrugated cardboard sheets to be warped to a greater degree. 
         [0038]    When the corrugated cardboard sheets are warped downwardly, in other words in the case of a down-warp, the edges of the corrugated cardboard sheets running transversely to the transport direction of the corrugated cardboard web, said edges thus being leading or trailing, are each arranged substantially such as to face downwardly, in other words they are arranged below a central region of the respective corrugated cardboard sheet running parallel to and between said edges. 
         [0039]    When the corrugated cardboard sheets are warped upwardly, in other words in the case of an up-warp, the edges of the corrugated cardboard sheets running transversely to the transport direction of the corrugated cardboard web, said edges thus being leading or trailing, are each arranged substantially such as to face upwardly, in other words they are arranged above a central region of the respective corrugated cardboard sheet running parallel to and between said edges. 
         [0040]    The first warp detection device arranged upstream of the cross-cutting assembly, preferably between the cross-cutting assembly and a longitudinal cutting and corrugating assembly for producing the partial corrugated cardboard webs, said longitudinal cutting and corrugating assembly being arranged upstream of the cross-cutting assembly may be different from or identical to the second warp detection device arranged downstream of the cross-cutting assembly for detecting the warp of the corrugated cardboard sheets. Preferably, each of them is in signal communication with the information processing device. It is expedient if the information processing device receives information from the first warp detection device relating to the partial corrugated cardboard webs. It is expedient if the information processing device receives information from the second warp detection device relating to the corrugated cardboard sheets. 
         [0041]    The embodiment in which the information processing device interrupts a regulation of the warp of the corrugated cardboard sheets when the warp of the partial corrugated cardboard webs is changed at the first warp detection device by means of at least one of the corrugated cardboard sheet warp influencing assemblies, and the information processing device then compares at the second warp detection device the actual warp of the corrugated cardboard sheets with the desired warp of the corrugated cardboard sheets, wherein the information processing device continues to do so until the actual warp of the corrugated cardboard sheets corresponds to the desired warp of the corrugated cardboard sheets, results in an extremely high quality of the corrugated cardboard sheets. 
         [0042]    The embodiment in which the information processing device immediately initiates a change of the warp of the corrugated cardboard sheets by means of at least one of the corrugated cardboard sheet warp influencing assemblies as soon as a change in the warp of the partial corrugated cardboard webs is detected at the first warp detection device, wherein preferably the information processing device stores the warp tendency from the first warp detection device towards the second warp detection device to reduce the regulation path to the first warp detection device, results in an extremely fast reaction time, thus allowing the number of corrugated cardboard sheets of poor quality to be reduced to a minimum. 
         [0043]    The embodiments set out above may also be preferred further developments of the method for the production of corrugated cardboard sheets. 
         [0044]    In the following sections, a preferred embodiment of the invention will be described by way of example with reference to the attached drawing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0045]      FIG. 1  shows a first part of a corrugated cardboard installation according to the invention, and 
           [0046]      FIG. 2  shows a second part of the corrugated cardboard installation according to the invention shown in  FIG. 1 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0047]    A corrugated cardboard installation as shown in the schematic view according to  FIGS. 1 and 2  comprises a first corrugated cardboard production assembly  1  for the production of an endless first single-face laminated corrugated cardboard web  2  and a second corrugated cardboard production assembly  3  for the production of an endless first single-face laminated corrugated cardboard web  4 . 
         [0048]    The first corrugated cardboard production assembly  1  is associated to a first splicer  5  and a second splicer  6  while the second corrugated cardboard production assembly  3  is associated to a third splicer  7  and a fourth splicer  8 . 
         [0049]    In order to unwind a non-endless first material web from a first material web roll  9 , the first splicer  5  comprises a first unwinding unit  10  and a second unwinding unit  12  in order to unwind a non-endless second material web from a second material web roll  11 . The non-endless first and second material webs are joined together by means of a joining and cutting unit (not shown) of the first splicer  5  in order to provide an endless first material web  13 . Each time a non-endless first material web is joined to a non-endless second material web, a first joint (not shown) is produced in the endless first material web  13 . 
         [0050]    The second splicer  6  corresponds to the first splicer  5 . Said second splicer  6  has a third unwinding unit  15  in order to unwind a non-endless third material web from a third material web roll  14 , and a fourth unwinding unit  17  in order to unwind a non-endless fourth material web from a fourth material web roll  16 . The non-endless third and fourth material webs are joined together by means of a joining and cutting unit (not shown) of the second splicer  6  in order to produce an endless second material web  18 . Each time a third material web is joined to a fourth material web, a second joint (not shown) is produced in the endless second material web  18 . 
         [0051]    Via at least one first deflection roller  19 , the endless first material web  13  is preferably supplied to a first preheating assembly  20  which comprises a first heatable preheating roller  21 . One side of the endless first material web  13  partly abuts against the outside of the first preheating roller  21 . The endless first material web  13  thus preheated is then preferably supplied to the first corrugated cardboard production assembly  1  via at least one second deflection roller  22 . 
         [0052]    The endless second material web  18  is preferably supplied to the first corrugated cardboard production assembly  1  via at least one third deflection roller  23 . 
         [0053]    The third splicer  7  corresponds to the first splicer  5 . Said third splicer  7  has a fifth unwinding unit  25  in order to unwind a non-endless fifth material web from a fifth material web roll  24 , and a sixth unwinding unit  27  in order to unwind a non-endless sixth material web from a sixth material web roll  26 . The non-endless fifth and sixth material webs are joined together by means of a joining and cutting unit (not shown) of the third splicer  7  in order to produce an endless third material web  28 . Each time a fifth material web is joined to a sixth material web, a third joint (not shown) is produced in the endless third material web  28 . 
         [0054]    The fourth splicer  8  substantially corresponds to the second splicer  6 . Said fourth splicer  8  has a seventh unwinding unit  30  in order to unwind a non-endless seventh material web from a seventh material web roll  29 , and an eighth unwinding unit  32  in order to unwind a non-endless eighth material web from an eighth material web roll  31 . The non-endless seventh and eighth material webs are joined together by means of a joining and cutting unit (not shown) of the fourth splicer  8  in order to produce an endless fourth material web  33 . Each time a seventh material web is joined to an eighth material web, a fourth joint (not shown) is produced in the endless fourth material web  33 . 
         [0055]    Via at least one fourth deflection roller  34 , the endless third material web  28  is preferably supplied to a second preheating assembly  35  which comprises a second heatable preheating roller  36 . One side of the endless third material web  28  partly abuts against the outside of the second preheating roller  36  so as to be heated from this side. The endless third material web  28  thus preheated is then preferably supplied to the second corrugated cardboard production assembly  3  via at least one fifth deflection roller  37 . 
         [0056]    The temperatures of the first preheating assembly  20  and the second preheating assembly  35  are changeable independently of each other, in other words the first and second preheating assemblies  20 ,  35  are heatable independently of each other. The preheating temperatures of the preheating rollers  21 ,  36  thereof are changeable. 
         [0057]    The endless fourth material web  33  is preferably supplied to the second corrugated cardboard production assembly  3  via at least one sixth deflection roller  38 . 
         [0058]    In order to produce, from the endless second material web  18 , an endless corrugated web  39  that is provided with a corrugation, the first corrugated cardboard production assembly  1  comprises a first corrugating roller  41  which is mounted for rotation about a first axis of rotation  40 , and a second corrugating roller  43  which is mounted for rotation about a second axis of rotation  42 . The corrugating rollers  41 ,  43  together form a roller gap allowing the endless second material web  18  to be passed through in order to be provided with a corrugation, the axes of rotation  40 ,  42  being parallel to each other. The corrugating rollers  41 ,  43  together form a first corrugating assembly. 
         [0059]    In order to join the first corrugated web  39  to the endless first material web  13  so as to form the first single-face laminated corrugated cardboard web  2 , the first corrugated cardboard production assembly  1  has a first glue application assembly  44  which in turn comprises a first glue metering roller  45 , a first glue tray (not shown) as well as a first glue application roller  46 . The first glue application roller  46  and the first corrugating roller  41  together form a glue application gap allowing the endless first corrugated web  39  to be passed through in order to be provided with a glue layer, with the first glue application roller  46  being partly arranged, in other words immersed, in the first glue tray. The glue provided in the glue tray is then applied to tips of the corrugation of the first corrugated web  39 . The first glue metering roller  45  abuts against the first glue application roller  46 , thus ensuring that an even glue layer is formed on the first glue application roller  46 . The first glue application roller  46  is displaceable relative to the first corrugating roller  41 , thus allowing the size of the glue application gap between said rollers  46 ,  41  to be changed. When the size of the glue application gap is changed, the amount of glue delivered from the first glue tray to the first corrugated web  39  is changed as well. 
         [0060]    In the first corrugated cardboard production assembly  1 , the endless first material web  13  is then joined to the first corrugated web  39  provided with glue. 
         [0061]    The first corrugated cardboard production assembly  1  has a first pressure belt device  47  for pressing the endless first material web  13  against the first corrugated web  39  provided with glue which in turn partly abuts against the first corrugating roller  41 . The first pressure belt device  47  is arranged above the first corrugating roller  41 . It ha a first pressure roller  49  mounted for rotation about a third axis of rotation  48 , and a second pressure roller  51  mounted for rotation about a fourth axis of rotation  50  as well as an endless pressure belt  52  which is guided around the pressure rollers  49 ,  51 . 
         [0062]    The first corrugating roller  41  partly engages, from below, a space between the pressure rollers  49 ,  51 , thus causing the pressure belt  52  to be deflected by the first corrugating roller  41 . It presses against the endless first material web  13  which is thus pressed against the first corrugated web  39  provided with glue, said corrugated web  39  abutting against the first corrugating roller  41 . 
         [0063]    For intermediate storage and buffering, the first single-face laminated corrugated cardboard web  2  is fed to a first storage assembly  53  where it is stored in loops. 
         [0064]    The second corrugated cardboard production assembly  3  is identical to the first corrugated cardboard production assembly  1 . In order to produce from the endless fourth material web  33  a second corrugated web  54  provided with a corrugation, the second corrugated cardboard production assembly  3  comprises a third corrugating roller  56  mounted for rotation about a fifth axis of rotation  55 , and a fourth corrugating roller  58  mounted for rotation about a sixth axis of rotation  57 . The third corrugating roller  56  and the fourth corrugating roller  58  together form a roller gap allowing the endless fourth material web  33  to be passed through in order to be provided with a corrugation, with the fifth axis of rotation  55  and the sixth axis of rotation  57  being parallel to each other. The third corrugating roller  56  and the fourth corrugating roller  58  together form a corrugating assembly. 
         [0065]    In order to join the endless second corrugated web  54  to the endless third material web  28  so as to form the second single-face laminated corrugated cardboard web  4 , the second corrugated cardboard production assembly  3  has a second glue application assembly  59  which in turn comprises a second glue metering roller  60 , a second glue tray (not shown) as well as a second glue application roller  61 . The second glue application roller  61  and third corrugating roller  56  together form a glue application gap allowing the endless second corrugated web  54  to be passed through in order to be provided with a glue layer, with the second glue application roller  61  being partly arranged, in other words immersed, in the second glue tray. The glue provided in the second glue tray is then applied to tips of the corrugation of the second corrugated web  54 . The second glue metering roller  60  abuts against the second glue application roller  61 , thus ensuring that an even glue layer is formed on the second glue application roller  61 . The second glue application roller  61  is displaceable relative to the third corrugating roller  56 , thus allowing the size of the glue application gap between said rollers  61 ,  56  to be changed. When the size of the glue application gap is changed, the amount of glue delivered from the second glue tray to the second corrugated web  39  is changed as well. 
         [0066]    In the second corrugated cardboard production assembly  3 , the endless third material web  28  is then joined to the second corrugated web  54  provided with glue from the second glue tray. 
         [0067]    The second corrugated cardboard production assembly  3  has a second pressure belt device  62  for pressing the endless third material web  28  against the second corrugated web  54  provided with glue which in turn partly abuts against the third corrugating roller  56 . The second pressure belt device  62  is arranged above the third corrugating roller  56 . It has a third pressure roller  64  mounted for rotation about a seventh axis of rotation  63 , and a fourth pressure roller  66  mounted for rotation about an eighth axis of rotation  65  as well as a second pressure belt  67  which is guided around the third and fourth pressure rollers  64  and  66 . 
         [0068]    The third corrugating roller  56  partly engages, from below, a space between the third and fourth pressure rollers  64  and  66 , thus causing the second pressure belt  67  to be deflected by the third corrugating roller  56 . It presses against the endless third material web  28  which is thus pressed against the second corrugated web  54  provided with glue, said corrugated web  54  abutting against the third corrugating roller  56 . 
         [0069]    For intermediate storage and buffering, the second single-face laminated corrugated cardboard web  4  is fed to a second storage assembly  68  where it is stored in loops. 
         [0070]    Downstream of the storage assemblies  53 ,  68 , a preheating assembly  69  is arranged which comprises third, fourth and fifth preheating devices  70 ,  71  and  72 . The third, fourth and fifth preheating devices  70 ,  71  and  72  are arranged one above the other. The fourth preheating device  71  is arranged between the preheating devices  70 ,  72 . 
         [0071]    The third preheating device  70  has a third heatable preheating roller  73  while the fourth preheating device  71  has a fourth heatable preheating roller  74 . The fifth preheating device  72  has a fifth heatable preheating roller  75 . The preheating rollers  73 ,  74 ,  75  are heatable independently of each other, in other words the preheating temperatures of the preheating rollers  73 ,  74 ,  75  are changeable. 
         [0072]    The first corrugated cardboard web  2  is fed to the third preheating device  70  so as to partly abut against the third preheating roller  73  with one side. The second corrugated cardboard web  4  is fed to the fourth preheating device  72  so as to partly abut against the fourth preheating roller  74  with one side. An endless cover web  76  is fed to the fifth preheating device  72  so as to partly abut against the fifth preheating roller  75  with one side. 
         [0073]    In order to unwind a non-endless ninth material web from a ninth material web roll  78 , a fifth splicer  77  comprises a ninth unwinding unit  79  and a tenth unwinding unit  81  in order to unwind a non-endless tenth material web from a tenth material web roll  80 . The non-endless ninth and tenth material webs are joined together by means of a joining and cutting unit (not shown) of the fifth splicer  77  in order to provide the endless cover web  76 . Each time a non-endless ninth material web is joined to a non-endless tenth material web, a joint is produced in the endless cover web  76 . 
         [0074]    Downstream of the preheating assembly  69 , a glue application assembly  82  is arranged which comprises a first glue application device  83  and a second glue application device  84  and is shown in  FIG. 2 . The first glue application device  83  has a first glue application roller  85  which is immersed into a first glue bath  86  so as to deliver glue from the first glue bath  86  to the preheated first corrugated cardboard web  2 . The first glue application roller  85  is displaceable such that the amount to glue delivered or deliverable to the first corrugated cardboard web  2  is changeable. 
         [0075]    The second glue application device  84  has a second glue application roller  87  which is immersed into a second glue bath  88  so as to deliver glue from the second glue bath  88  to the preheated second corrugated cardboard web  4 . The second glue application roller  87  is displaceable such that the amount to glue delivered or deliverable to the second corrugated cardboard web  4  is changeable. The first glue application roller  85  and the second glue application roller  87  are displaceable independently of each other. 
         [0076]    In the glue application assembly  82 , the cover web  76  is guided over a seventh deflection roller  89 . The second glue application device  84  is arranged between the first glue application device  83  and the seventh deflection roller  89 . 
         [0077]    A heating and pressing assembly  90  is arranged downstream of the glue application assembly  82 . The heating and pressing assembly  90  comprises a horizontal table  91  with heating members  92 . The heating temperature of the heating members  92  is changeable. The heating and pressing assembly  90  has an endless pressure belt  94  provided above the table  91 , the pressure belt  94  being deflected via rollers  93 . The pressure belt  94  allows the first corrugated cardboard web  2  to be sprayed with steam. A pressure gap  95  is formed between the pressure belt  94  and the table  91  through which the first corrugated cardboard web  2  provided with glue, the second corrugated cardboard web  4  provided with glue and the cover layer  76  are guided so as to be pressed together. The heating members  92  are arranged adjacent to the cover layer  76  while the pressure belt  94  is arranged adjacent to the first corrugated cardboard web  2 . In the heating and pressing assembly  90 , an endless corrugated cardboard web  96  is formed which comprises five layers. 
         [0078]    Downstream of the heating and pressing assembly  90 , the corrugated cardboard installation has a longitudinal cutting and corrugating assembly  97 . At its inlet end, the longitudinal cutting and corrugating assembly  97  comprises two corrugating stations  98  arranged one behind the other and two longitudinal cutting stations  99  arranged one behind the other. 
         [0079]    Each of the corrugating stations  98  is provided with corrugating tools  100  arranged one above the other such as to form a pair between which the five-layer corrugated cardboard web  96  is passed through. 
         [0080]    Each of the longitudinal cutting stations  99  is provided with rotatably drivable knives  101  which are engageable with the five-layer corrugated cardboard web  96  for cutting said corrugated cardboard web  96  in a longitudinal direction. When immersed in the five-layer corrugated cardboard web  96 , the knives  101  interact with rotatably driven brush rollers (not shown) arranged opposite to each other. By means of the longitudinal cutting stations  99 , the previously undivided five-layer corrugated cardboard web  96  is dividable into a number of endless partial corrugated cardboard webs  110  which are transported in a transport direction  105  and are initially arranged next to each other. 
         [0081]    Downstream of the longitudinal cutting and corrugating assembly  97 , a short and cross-cutting assembly  102  is arranged. The short and cross-cutting assembly  102  has a casing  103  in which a roller  104  is mounted for rotation about an axis of rotation  106  extending perpendicular to the transport direction  105  of the corrugated cardboard web  96 . The casing  103  of the short and cross-cutting assembly  102  is configured such that the five-layer corrugated cardboard web  96  is transportable through the short and cross-cutting assembly  102  below the rotatably driven roller  104 . The roller  104  is provided with a radially outwardly extending knife  107  which extends across the entire width of the five-layer corrugated cardboard web  96  in a direction perpendicular to the transport direction  105 . 
         [0082]    In the casing  103 , several support units  108  are arranged below the five-layer corrugated cardboard web  96  such as to be adjacent to each other and perpendicular to the transport direction  105 . Each support unit  108  comprises a cutting support  109  also referred to as anvil which is mounted to a piston rod of a hydraulic cylinder (not shown). The piston rod is displaceable in the transport direction  105  in a casing of the hydraulic cylinder. The end of the casing of the hydraulic cylinder remote from the piston rod is mounted to the casing  103  of the short and cross-cutting assembly  102 . Each cutting support  109  is movable into a first and second position by means of the associated hydraulic cylinder. In the first position, which is the cutting position, the cutting support  109  is located directly below the roller  104 . The vertical distance of the roller  104  from the cutting support  109  is selected such that when the roller  104  rotates about the axis of rotation  106 , the knife  107  is located just above the cutting support  109  so that there is no direct contact therewith. In the second position, which is the non-cutting position, the piston rod of the hydraulic cylinder is fully extended so that the cutting support  109  is located in front of the roller  104  when seen in the transport direction  105 . The short and cross-cutting assembly  102  on the one hand allows one to reliably remove start-up waste and to change orders or formats on the other. In the event of a change of format, the short and cross-cutting assembly  102  allows connection cuts to be produced in a direction perpendicular or oblique to the transport direction  105 , said connection cuts interconnecting the longitudinal cuts produced by means of the longitudinal cutting stations  99 , with the result that the partial corrugated cardboard webs  110  preferably remain endless. 
         [0083]    Downstream of the short and cross-cutting assembly  102 , a switch  111  is arranged which comprises a feed table  112  for feeding the partial corrugated cardboard webs  110  and a discharge table unit  113  comprising three discharge tables  114  for discharging the partial corrugated cardboard webs  110  in three directions. Preferably, several switch members are provided to facilitate transfer of the partial corrugated cardboard webs  110  from the feed table  112  to the discharge tables  114 , said switch members being pivotably arranged at the feed table  112  next to each other in a direction transverse to the transport direction  1054  so as to be pivotable relative to the discharge tables  114  into corresponding angular positions. A different number of discharge table units  113  is alternatively conceivable as well. 
         [0084]    Downstream of the switch  111 , a cross-cutting assembly  115  is provided which has three cross-cutting units  116  arranged one above the other. Each cross-cutting unit  116  comprises two rotatably drivable cross-cutting rollers  117  which are in each case arranged one above the other such as to form a pair and extend in a direction transverse to the transport direction  105 . Each cross-cutting roller  117  has a radially outwardly extending cross-cutting knife  118  allowing the partial corrugated cardboard webs  110  to be cut through entirely in the transverse direction so as to produce corrugated cardboard sheets  119 . The cross-cutting knives  118  of each cross-cutting unit  116  interact with each other for cross-cutting the partial corrugated cardboard webs  110  and are driven accordingly. 
         [0085]    Downstream of each cross-cutting unit  116 , a conveyor belt  120  is arranged allowing the corrugated cardboard sheets  119  thus cut to be transported to stacking and deposit units  121 . Each conveyor belt  120  is associated to one stacking and deposit unit  121 . 
         [0086]    The corrugated cardboard installation further comprises a warp detection assembly  122  for detecting the warp of the partial corrugated cardboard webs  110  and of the corrugated cardboard sheets  119 . 
         [0087]    To this end, the warp detection assembly  122  has a first warp detection device  123  which is arranged upstream of the cross-cutting assembly  115  and extends transversely to the transport direction  105  across the entire width of the partial corrugated cardboard webs  110 . A closer look reveals that said warp detection device  123  is arranged between the longitudinal cutting and corrugating assembly  97  and the cross-cutting assembly  115 . An even closer look reveals that said warp detection device  123  is arranged between the short and cross-cutting assembly  102  and the cross-cutting assembly  115 . A closer look reveals that the first warp detection device  123  is arranged between the short and cross-cutting unit  102  and the switch  111 . Preferably, it is immovable at least in the transport direction  105 . 
         [0088]    The first warp detection device  123  is capable of detecting the warp of the partial corrugated cardboard webs  110 . To this end, the first warp detection device  123  comprises for instance a first warp detection sensor which is arranged above or below the partial corrugated cardboard webs  110 . Alternatively, two warp detection sensors are provided which are arranged opposite to each other, with the partial corrugated cardboard webs  110  then passing between said warp detection sensors. 
         [0089]    The first warp detection device  123  is in particular capable of detecting the warp of the partial corrugated cardboard webs  110  in the transport direction  105  and/or in an upward and/or downward direction transverse thereto relative to a plane, in other words relative to their extension in a plane. 
         [0090]    The first warp detection device  123  is in signal communication, via a first signal line  124 , with an information processing device  125 . Via the first signal line  124 , warp information relating to the individual partial corrugated cardboard webs  110  are transmitted to the information processing device  125 . 
         [0091]    The warp detection assembly  122  further comprises a second warp detection device  126  which is arranged downstream of the cross-cutting assembly  115 . A closer look reveals that said second warp detection device  126  is arranged between the cross-cutting assembly  115  and the stacking and deposit units  121 . 
         [0092]    The second warp detection device  126  in turn has three second warp detection units  127 . Each conveyor belt  120  is associated to one warp detection unit  127 . Each warp detection unit  127  may comprise a warp detection sensor which is arranged above or below the respective conveyor belt  120  and is preferably immovable at least in the direction of conveyance thereof. Alternatively, each warp detection unit  127  has two warp detection sensors which are arranged in pairs above and below the respective conveyor belt  120  so as to detect the warp of the corrugated cardboard sheets  119  transported thereon. 
         [0093]    The warp detection units  127  are capable of detecting the warp of the corrugated cardboard sheets  119  in their respective transport directions and/or in an upward and/or downward direction transverse thereto relative to a plane, in other words relative to their extension in a plane. 
         [0094]    Each warp detection unit  127  is in signal communication, via a second signal line  128 , with the information processing device  125 . Via said second signal lines  128 , warp information relating to the corrugated cardboard sheets  119  is transmittable to the information processing device  125 . 
         [0095]    The information processing device  125  is in particular capable of changing or correcting desired values for the corrugated cardboard webs  2 ,  4 ,  96  or the corrugated cardboard webs  110 , in particular the preheating temperature of the first preheating roller  21 , the preheating temperature of the second preheating roller  36 , the preheating temperature of the third preheating roller  73 , the preheating temperature of the fourth preheating roller  74 , the preheating temperature of the fifth preheating roller  75 , the heating temperature of the heating members  92 , the supply of steam via the pressure belt  94 , the glue gap in the first corrugated cardboard production assembly  1  and/or the glue gap in the second corrugated cardboard production assembly  3 . 
         [0096]    To this end, the information processing device  125  is in signal communication, via a third signal line  129 , with the first preheating assembly  20 , thus allowing the preheating temperature of its preheating roller  21  to be changed according to requirements in order to influence the warp of the corrugated cardboard sheets  119 . 
         [0097]    The information processing device  125  is in signal communication, via a fourth signal line  130 , with the first glue application assembly  44  of the first corrugated cardboard production assembly  1 , thus allowing the glue application roller  46  thereof to be displaced according to requirements in order to change the application of glue, in particular the amount of glue applied, so as to influence the warp of the corrugated cardboard sheets  119 . 
         [0098]    The information processing device  125  is in signal communication with the second preheating assembly  35  via a fifth signal line  131 , thus allowing the preheating temperature of the preheating roller  36  thereof to be changed according to requirements in order to influence the warp of the corrugated cardboard sheets  119 . 
         [0099]    The information processing device  125  is in signal communication with the second glue application assembly  59  of the second corrugated cardboard production assembly  3  via a sixth signal line  132 , thus allowing the glue application roller  61  thereof to be displaced according to requirements so as to change the application of glue, in particular the amount of glue applied, to influence the warp of the corrugated cardboard sheets  119 . 
         [0100]    The information processing device  125  is further in signal communication, via a seventh signal line  133 , with the third preheating device  70 , the fourth preheating device  71  and the fifth preheating device  72 , thus allowing the preheating temperatures of their preheating rollers  73 ,  74 , and  75 , respectively, to be changed independently of each other according to requirements in order to influence the warp of the corrugated cardboard sheets  119 . 
         [0101]    The information processing device  125  is in signal communication with the first glue application assembly  83  and the second glue application assembly  84  via an eighth signal line  134 , thus allowing the position of their glue application rollers  85  and  87 , respectively, to be changed in order to influence the warp of the corrugated cardboard sheets  119 . 
         [0102]    The information processing device  125  is in signal communication with the heating and pressure assembly  90  via a ninth signal line  135 , thus allowing the heating temperature of its heating members  92  and/or the supply of steam via the pressure belt  94  to be changed according to requirements in order to influence the warp of the corrugated cardboard sheets  119 . In order to influence the warp of the corrugated cardboard sheets  119 , at least one of the corrugated cardboard sheet warp influencing assemblies  20 ,  35 ,  44 ,  59 ,  69 ,  82 ,  90  is actuated correspondingly via the respective signal line  124 ,  128  to  135 . 
         [0103]    When the information processing device  125  determines at the second warp detection device  126  that a warp of the corrugated cardboard sheets  119  differs from a desired warp of the corrugated cardboard sheets  119 , the information processing device  125  stores the warp of the partial corrugated cardboard webs  110  and/or warp information relating thereto, said information being detected by the first warp detection device  123 , as well as the warp of the corrugated cardboard sheets  119  and/or warp information relating thereto, said information being detected by the second warp detection device  126 . 
         [0104]    When the warp of the partial corrugated cardboard webs  110  is changed at the first warp detection device  123  by means of at least one of the corrugated cardboard warp influencing assemblies  20 ,  35 ,  44 ,  59 ,  69 ,  82 ,  90 , the information processing device  125  interrupts a warp regulation of the corrugated cardboard sheets  119 . 
         [0105]    At the second warp detection device  126 , the information processing device  125  then compares the actual warp of the corrugated cardboard sheets  119  with the desired warp of the corrugated cardboard sheets  119 . The information processing device  125  continues to do so until the actual warp of the corrugated cardboard sheets  119  corresponds to the desired warp of the corrugated cardboard sheets  119 . 
         [0106]    When the first warp detection device  123  detects a change in the warp of the partial corrugated cardboard webs  110 , the information processing device  125  immediately initiates a change of the warp of the corrugated cardboard sheets  119  by means of at least one of the corrugated cardboard sheet warp influencing assemblies  20 ,  35 ,  44 ,  59 ,  69 ,  82 ,  90 . 
         [0107]    The warp tendency from the first warp detection device  123  towards the second warp detection device  126  is stored in the information processing assembly  125  to reduce the regulation path to the first warp detection device  123 . 
         [0108]    It is advantageous if the information processing device  125  comprises a programmable logic controller  136  for controlling the heating and preheating temperatures as well as the application of glue. 
         [0109]    It is advantageous if the information processing device  125  comprises a user interface. The user interface allows a user to manipulate the regulation processes in the corrugated cardboard installation, in other words the warp of the corrugated cardboard sheets  119 , to be influenced.