Patent Publication Number: US-6336398-B1

Title: Calender for webs of paper or a similar material

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 U.S.C. §119 of German Patent Application No. 198 32 006.3, filed on Jul. 16, 1998, the disclosure of which is expressly incorporated by reference herein in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a calendar for manufacturing webs of paper or a similar material. More specifically, the present invention relates to a calendar having two roll stacks, each having a deflection adjustment roll on at least one end, whose sleeve is supported by a deflection adjustment device on a fixed bracket. 
     2. Discussion of Background Information 
     In a known calender of this type, such as disclosed in DE 196 33 671 A1, two roll stacks of five rolls each are attached to a stanchion, one above the other, in a common vertical plane. The top roll and the bottom roll of each stack are deflection adjustment rolls. Each top roll is fixed to the stanchion. The bottom roll is fastened to a carriage that can be moved and loaded by a hydraulic cylinder. The roll sleeves are supported at their ends on the associated bracket. The bracket is fastened to either the stanchion or the carriage. There are also known deflection adjustment rolls of the sleeve lift type, for example, as disclosed in DE 30 04 913 C2. For these rolls, the roll sleeve is not supported on the bracket, but can be moved relative to the bracket so that the deflection adjustment device can be simultaneously used as a loading device. 
     SUMMARY OF THE INVENTION 
     The present invention a provides a calender that provides additional options for web treatment compared to the prior art. 
     In the present invention, as deflection adjustment roll of one roll stack and a deflection adjustment roll of a second roll stack are of the sleeve lift type. They are adjacent to each other, and can form an additional nip that can be closed by the sleeve lift. The effective direction of the deflection adjustment device alternatively points toward the associated roll stack or toward the other deflection adjustment roll. 
     If the effective direction is toward the associated roll stack, the calendar operates normally. However, if the effective direction is toward the other deflection adjustment roll, then an additional nip is formed, which can be used alone. If the two adjacent deflection adjustment rolls have an elastic cover, a matte satination is defined between the rolls. When manufacturing with the additional nip, the other rolls of the two roll stacks are not used, and can therefore be replaced or repaired. Thus, when one or more of the intermediary rolls needs to be repaired or replaced, the calendar can continue to operate using the adjacent deflection adjustment rolls. 
     Deflection adjustment devices are known in a wide variety of forms. For the most part, they function with hydrostatic support devices, particularly in the form of a series of support element that define the effective direction. It is therefore preferable that the deflection adjustment device of the present invention include a series of support elements, which can be moved through an angle (i.e., rotate) by an adjusting device. This minimizes the structural expense of the support device. In addition, a guide for the directed sleeve lift moves with the series of support elements. 
     As an alternative, the deflection adjustment device can include two series of support elements offset from each other. These support elements can be intentionally activated. 
     Preferably, the bearings for the bracket have at least one deflection adjustment roll cam with which the distance between adjacent deflection adjustment rolls can be changed. This cam can close the nip between the adjacent deflection rolls (the additional “nip”) if the sleeve lift alone is insufficient. 
     Preferably, the cams, together with the bracket, can be rotated through an angle by the adjusting device. Only one adjusting device is, therefore, needed to adjust the bracket and cams. 
     The two roll stacks preferably have a common central plane. This allows a common guide to be used on the stanchion. 
     Preferably, the common central plane extends obliquely to the horizontal. The resulting calendar has a height less than a 10-roll calendar with a vertical roll stack, and a length less than two 5-roll calenders with vertical roll stacks arranged next to each other. 
     In an alternative, the central planes of the two roll stacks can form an angle, particularly an acute angle, in relation to each other. 
     Preferably, the roll stacks have an odd number of rolls, each nip is defined by a hard roll and an elastic roll, and the deflection adjustment rolls that define the additional nip have an elastic cover. When using both roll stacks, this produces a glossy satination of the paper in which the two sides of the web side alternatively rest against the hard, smooth rolls. A matte satination is produced when only the additional nip is used. 
     The above noted benefits are particularly realized with combinations of roll stacks having 3, 5, or 7 rolls. Two roll stacks with 5 roll are preferred because of a high degree of uniformity in the paper web treatment. 
     In an exemplary embodiment, first and second roll stacks have first and second deflection adjustment rolls on an end thereof, respectively. Each of the first and second deflection adjustment rolls has a sleeve lift, and a sleeve supported by a deflection adjustment device on a fixed bracket. The first and second deflection adjustment rolls are adjacent to each other to define an additional nip therebetween that can be at least partially closed by the sleeve lift. An effective direction of the deflection adjustment device of the first deflection adjustment roll alternatively points toward the first roll stack and the second deflection adjustment roll, and an effective direction of the deflection adjustment device of the second deflection adjustment roll alternatively points toward the second roll stack and the first deflection adjustment roll. 
     According to a feature of the above embodiment, the deflection adjustment device of the first and second deflection adjustment rolls has a series of supporting elements that can be rotated by an adjusting device. Bearings for the bracket have at least one cam that can change a distance between the first and second deflection adjustment rolls. The adjusting device rotates the cam and the bracket. 
     In another feature of the above embodiment, the first and second roll stacks have a substantially common central plane, which preferably extends obliquely to a horizontal plane. 
     The first and second roll stacks may each have an odd number of rolls of alternative hard rolls and elastic rolls to define a plurality of nips therebetween, and the first and second deflection adjustment rolls have an elastic cover. The odd number is preferably 5. 
     According to another embodiment of the invention, a calendar for treating a material web includes first and second roll stacks having adjacent first and second deflection adjustment rolls on an end thereof, respectively, to define an additional nip therebetween. Each of the first and second deflection adjustment rolls have a deflection adjustment device. An adjusting device can move each of the deflection adjustment devices of the first and second deflection adjustment rolls to a first position in which an effective direction of each of the deflection adjustment devices of the first and second deflection adjustment rolls is toward the first and second roll stacks, respectively, and a second position in which the effective direction is toward the second and first deflection adjustment rolls, respectively. A closing device can open and close the additional nip when the deflection adjustment devices of the first and second deflection adjustment rolls are in the second position. 
     The deflection adjustment devices of the first and second deflection adjustment rolls preferably have a series of supporting elements that can be rotated by the adjusting device. The adjusting device includes bearings on a bracket having at least one cam that can change a distance between the first and second deflection adjustment rolls. The adjusting device rotates the cam and the bracket. 
     According to various features of the above embodiment, the first and second roll stacks preferably have a substantially common central plane. The substantial common central plane extends obliquely to a horizontally plane. The first and second roll stacks each have an odd number of rolls (preferably 5) of alternative hard rolls and elastic rolls to define a plurality of nips therebetween, and the first and second deflection adjustment rolls have an elastic cover. 
     A method for operating a calender is also provided. The calender includes first and second roll stacks having adjacent first and second deflection adjustment rolls on an end thereof, respectively, to define an additional nip there between. Each of the first and second deflection adjustment rolls have deflection adjustment device. The method includes moving each of the deflection adjustment devices of the first and second deflection adjustment rolls to a first position in which an effective direction of each of the deflection adjustment devices of the first and second deflection adjustment rolls is toward the first and second roll stacks, respectively, whereby the calendar can perform a first operation on the web. Each of the deflection adjustment devices of the first and second deflection adjustment rolls are moved to a second position in which the effective direction is toward the second and first deflection adjustment rolls, respectively. The first and second deflection adjustment rolls are moved toward each other to close the additional nip, whereby the calendar can perform a second operation on the web, the second operation being different from the first operation. 
     Moving each of the deflection adjustment devices of the first and second deflection adjustment rolls to the first position and moving each of the deflection adjustment devices of the first and second deflection adjustment rolls to the second position preferably includes rotating, by 180°, each of the deflection adjustment devices of the first and second deflection adjustment rolls. 
     Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure and the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of certain embodiments of the present invention, in which like numerals represent like elements throughout the several views of the drawings, and wherein: 
     FIG. 1 is a schematic side view of a calender according to the invention; 
     FIG. 2 is a cross-section through the central region of a deflection adjustment roll; 
     FIG. 3 is a cross-section through the end region of a deflection adjustment roll; and 
     FIG. 4 is a schematic representation of the bearing of the bracket of a deflection adjustment roll. 
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT 
     The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice. 
     Referring now to FIG. 1, a calender  1  has an upper 5-roll stack  2  and a lower 5-roll stack  3 . The upper roll stack  2  includes a top roll  4 , three intermediary rolls  5 ,  6 , and  7 , and a bottom roll  8 . The lower roll stack  3  includes a top roll  9 , three intermediary rolls  10 ,  11 , and  12 , and a bottom roll  13 . 
     The top and bottom rolls  4 ,  8 ,  9 , and  13  are deflection adjustment rolls of the sleeve lift type. These rolls can have the same structure as one another so that one reserve roll suffices for all four end rolls. Referring now also to FIGS. 2 and 3, each deflection adjustment roll has a sleeve  14 , which is supported by a deflection adjustment device  15  on a bracket  17  that is fixedly secured to the stanchion  16  during operation. The deflection adjustment device  15  includes a series of hydrostatic support elements  18 , which are supplied in a known manner with pressure fluid via a respective pressure chamber  19  such that the deflection adjustment device  15  is also used as a loading device. At the ends, the roll sleeve  14  is supported on a bearing ring  20 , which can be moved over its entire length in a lift direction on a lift guide  21 . In addition, bracket  17  can be rotated by an angle of 180° along the direction indicated by arrow  23  by an adjusting device  22  so that the effective direction of the deflection adjustment device  15  points in the opposite direction, as shown by the series of support elements  18 ′ depicted with dashed lines. 
     The uppermost intermediary rolls  5  and  10  are mounted fixedly on the stanchion  16 . With the accompanying top rolls  4  and  9 , if the defection adjustment device  15  is in the position shown in FIG. 2, the paper web  24  is subject to a very high line load, with a corresponding high compressive stress in the nips  25  and  26  of the upper roll stack  2  or the lower roll stack  3  that are first in the running direction. 
     The intermediary rolls  6 ,  7 ,  11 , and  12  are each supported on a lever  27 , which pivots around a pivot axle fixed to the stanchion. If the deflection adjustment devices  15  of the bottom rolls  8  and  13  are in the position shown with dashed lines in FIG. 2, the nips  28 ,  29 , and  30  of the upper roll stack  2  and the nips  31 ,  32 , and  33  of the lower roll stack  3  are correspondingly loaded. The level of loading is independent of nips  25  or  26 . Four sections are therefore produced in which the paper web  24  can be treated differently, so that a large number of different paper qualities can be produced. 
     During normal operation, an open additional nip  34  remains between the two roll stacks  2  and  3 , through which the paper web  24  travels unhindered. Preferably, one side of the web is satinated in the upper roll stack  2 , and the other side of the web is satinated in the lower roll stack  3 . 
     The top and bottom rolls  4 ,  8 ,  9 , and  13 , as well as the intermediary rolls  7  and  11  are elastic rolls, while the remaining intermediary rolls  5 ,  7 ,  10 , and  12  are heated, hard rolls. However, other combinations may be used. 
     The distance between the two deflection adjustment rolls  9  and  10  is slight so that the additional nip  34  can be closed, for example by 30-40 mm, with the roll lift. To this end, it is only necessary to rotate the deflection adjustment devices  15  of the two end rolls  8  and  9  toward each other with the aid of the adjusting device  22 , and to then supply the pressure fluid under appropriate pressure. A matte satination can then be carried out using this additional nip  34 , since the two deflection adjustment rolls  8  and  9  have an elastic cover. Therefore, this provides an additional way to treat the paper web without significant additional cost. 
     Referring now also to FIG. 4, if the open additional nip  34  is so large that sleeve lift cannot close it, then the bracket  91  of the top roll  9  can be supported in a dome  92 , which is in turn carried by a cam disk  93 . Cam disk  93  can be rotated, together with the bracket  91 , by 180° in the bearing  94  by the adjusting device  22 . In this manner, the open additional nip  34  can be reduced, for example, by 80 mm, which also opens nips  28  and  29 . 
     The axes of the rolls  4  to  13  are arranged generally in a common place E, which is preferably inclined by 45° to the horizontal. The stanchion  16  also extends obliquely. It can therefore be supported at two points, namely with a lower support face  35  on a lower bearing face  36  that is fixed to the building, and with an upper support face  37  on an upper bearing face  38  that is fixed to the building. The bearing face  37  is arranged on a foot  39  that is attached to the stanchion  16  close to its upper end. The bearing faces  36  and  38  extend horizontally and are each embedded on a concrete pedestal or footing  40  or  41 . The stanchion  16  is thus largely insensitive to vibrations. 
     In FIG. 1, calender  1  is arranged between the last drying roll  42  of a drying section of a paper machine and a winding device  43 , for example, a roll cutting and winding device. The drying roll and the winding device are arranged approximately at the same height above a working plane  44  of calender  1 . The paper web  24  extends at a relatively slight incline between the drying roll  42  and the entry into the calendar  1 , as well as between the exit from the calender  1  and the winding device  43 . This facilities the insertion of the paper web during online operation. The same advantage is also realized when the paper web is introduced from the drying roll  42  into the calendar  1  from below and exits at the top toward the winding device  43 . 
     A web feeder device  45 , which functions, for example, with cable clamping, conveys web  24  through all of the nips  25 - 33  of the two roll stacks  2  and  3 , as well as the additional nip  34 . One insertion procedure is therefore sufficient for both roll stacks. The insertion movement is aided by virtue of the fact that each of the rolls of calendar  1  and each of the associated guide rolls has a respective drive  46 . Paper treatment proceeds depending on which of the nips are closed. 
     A second web inserting device  47  is shown with dashed lines, which supplies only the additional nip  34 . With the matte satination of a web inserted in this manner, the remaining rolls can be repaired or replaced. A semi-matte operation is produced, for example, when only the uppermost nip  25  is used. 
     The precise inclination of the stanchion  16  is a function of on-site conditions. Plus or minus 10° from 45° fall within the preferred range, although other angles are possible. 
     The oblique inclination with the roll stacks arranged on top has the additional advantage that, for the purpose of exchanging rolls, they can be better accessed and exchanging using a crane  48  and a corresponding crane control. In particular, the bearings of the roll to be changed can be moved out along a guide perpendicular to the plane E, as shown with dashed lines in FIG. 1, by a hydraulic adjusting device  49 . The piston of a hydraulic cylinder that extends along the lever  27  is primarily used by the adjusting device  49 . In the outside position, the crane  48  can directly grasp the roll ends and remove the roll vertically. 
     It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to certain embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.