Patent Grant
7340999
The present application claims priority under 35 U.S.C. §119 of German Patent Application No. 10 2004 003 715.9-27, filed on Jan. 24, 2004, the disclosure of which is expressly incorporated by reference herein in its entirety.
1. Field of the Invention
The invention relates to a method for operating a multi-roll calender in which a web is guided either through several nips of the calender or through only at least one end nip, depending on a desired surface quality. Furthermore, the invention relates to a calender with a roll stack of several rolls and nips formed between adjacent rolls, in which an end nip limited by an end roll and an intermediate roll is formed by a hard roll and a soft roll, and with a device for holding the intermediate roll limiting the end nip.
2. Discussion of Background Information
Such a method and such a calender are known, e.g., from German Application No. DE 202 00 584 U1. A calender of this type is used mainly to glaze a paper web. With this glazing the paper web is on the one hand condensed, but on the other hand also receives certain surface properties. The aim with the treatment of the paper web in a calender of this type is above all to be able to influence the smoothness of the paper web.
As a first approximation, it can be assumed that, the more nips that are involved in the glazing, the smoothness will be improved further. However, there are also grades of paper in which a high smoothness is not required or not even desired.
Depending on the grade of paper, therefore, either a multi-nip operation is used in which the web is guided through several nips, or a single-nip operating mode in which the web is treated only in a single nip. This nip is then arranged between an end roll and the adjacent intermediate roll. This intermediate roll can be fixed so that with the single-nip operating mode the remaining intermediate roll and the remaining end roll do not have to rotate along with it when “empty”, thus without a web in the nip.
However, the treatment in a single nip in some cases also produces too great a smoothness. In the so-called “matt glazing” the aim is to be able to treat the web between two soft rolls. As a rule, a separate matt calender is necessary for this, which, as an auxiliary unit, incurs expense and requires space.
Supercalenders are also known in which a so-called changeover nip is formed of two soft nips approximately in the middle. If this changeover nip were used for matt glazing, all the rolls would have to be in operation, thus also the upper and lower roll and the other intermediate rolls, although they are not involved in the glazing process. This leads to an unnecessary wear of the surfaces of the rolls and to increased energy consumption. Such an operating mode is thus not desirable as a rule.
The present invention expands the treatment possibilities in a multi-roll calender.
Accordingly, the present invention provides a method of the type mentioned at the outset in that with exclusive use of at least one end nip, the end nip is either limited by a hard roll and a soft roll, or the hard roll is replaced by a soft roll and the end nip is limited by two soft rolls. Moreover, the replaced roll is connected to a temperature control device and the temperature control device is operated with a tempering capacity that depends on the type of the replaced roll.
The expense of the changeover between a matt glazing operating mode, in which the web is glazed between two soft rolls, and a different operating mode in which the web is glazed between a hard roll and a soft roll, is kept relatively low according to this embodiment. In the majority of cases, the hard roll is heated, because an increased temperature leads to an improved smoothness on the surface of the paper web. A temperature control device for the heated roll is therefore present. The temperature control device works in operation such that a heat transfer medium is fed to the hard roll at an increased temperature. The same temperature control device can now be used to remove heat that is generated during the operation of the soft roll. This heat is generated mainly by the working of the elastic cover of the soft roll. The same heat transfer fluid can be used for this. However, the task of this heat transfer fluid has changed. The aim is no longer to introduce heat into the roll, but to transport heat out of the roll. Through the common use of the temperature control device for both operating modes, the problem of the replaced soft roll becoming too heated is thus avoided. Although the temperature control device that is used to heat the hard roll often already has a cooling stage in order to be able to cool down the hot roll before dismantling, the amounts of heat to be removed here are relatively small. Cooling must not occur too quickly, so as to avoid thermal stresses in the hard roll during cooling. Also, the temperature control device for cooling has been hitherto used only for relatively short periods, but not for continuous operation. In contrast, according to the invention it is provided that the temperature control device can also be used for heat removal in the normal glazing operation.
It is hereby preferred for the operating mode of the temperature control device to be switched over with the replacement of the roll. To this end, for example, a switchover device can be available on the roll, which automatically switches over the temperature control device upon installation. Switchover devices of this type also include identifiers that are arranged on the roll and that can be automatically recognized by a recognition device, which then controls the operation of the temperature control device.
A scraper device is preferably installed on the replaced roll depending on the type of the replaced roll. The operating parameters of the scraper device, e.g., blade angle and blade load, are then adapted to the surface of the roll to be cleaned. As a rule, the contact pressure of the blade is reduced with a soft roll having an elastic cover. It can also be provided here for this adjustment to occur automatically with the replacement of the roll.
The temperature control device is preferably operated with oil. Oil is able to transport greater amounts of heat into the roll, in the case of a hard heated roll, and to transport heat out of the roll in the case of a soft roll.
The invention is directed to a calender of the type mentioned at the outset that includes a soft replacement roll having a connection arrangement for a temperature control device that corresponds geometrically to the connection arrangement of the hard roll limiting the end nip. The temperature control device is designed for heating a hard roll and removing heat from a soft roll.
With a calender of this type it is now possible, as set forth above, to matt glaze a web, in particular a paper web, by using two soft rolls, as well as to glaze in a “normal” manner, where a hard heated roll and a soft roll are used in the end nip. Since the hard heated roll and the replacement roll that can be used instead of this hard heated roll have the same geometric connection arrangement, it is easily possible to connect them to the same temperature control device without additional conversion measures being necessary. Since the temperature control device can be used both for supplying heat to the hard heated roll and for removing heat from the soft roll, no conversion is necessary here, either. The expense for the changeover between different glazing operating modes is thus kept relatively low.
The replacement roll and the replaceable hard roll preferably feature a switchover device that converts the temperature control device to the operating mode suitable for the operation of the respective roll. It is thus possible to convert the operating mode automatically. Therefore, there is no danger that the temperature control device will accidentally heat the soft roll or cool the hard roll. The risk of breakdowns that result from an inappropriate tempering of the respective rolls is thus kept relatively low.
The intermediate roll limiting the end nip is preferably embodied as a hard roll. Thus, a soft roll is used as an end roll, which in addition is embodied as a sag compensation roll. The replacement roll can then be embodied in a more cost-effective manner.
A scraper arrangement is preferably arranged at the position of the replacement roll, the operating parameters of which can be adjusted depending on the type of roll arranged in the position of the replacement roll. The scraper arrangement can be used to clean the surface of the respective roll in operation when using a hard roll as well as when using a soft roll. As the operating parameters, e.g., blade load and blade angle, can be adjusted depending on the type of installed roll, a conversion between the different operating modes is easily possible.
A web run through both end nips is preferably provided, and both hard intermediate rolls limiting the end nips can be replaced by a soft roll. A matt glazing operation in two nips is thus possible, namely in the two end nips. Both replaceable intermediate rolls can be connected to the temperature control device in order to supply heat when a hard roll is used and to remove heat when a soft roll is used.
The web run preferably runs through all the nips of the calender, whereby all nips are opened except for the end nips. Thus on the one hand the “normal” web run is retained, thus all guide devices and auxiliary units, such as dampening devices, can also be used as before. On the other hand, the rolls not involved in the glazing process are conserved. It is necessary only to replace the hard and heated intermediate rolls adjacent to the end rolls with soft rolls.
The present invention is directed to a process for operating a multi-roll calender depending upon a desired surface quality, in which the multi-roll calender includes a plurality of nips located between end nips formed by replaceable rolls and end rolls. The process including selectively guiding a web though several nips of the multi-roll calender and at least one end nip of the multi-roll calender, and when the web is selectively guided through the at least one end nip, selectively replacing the replaceable roll with one of a hard and a soft roll to form the at least one end nip with a hard roll and a soft roll or with two soft rolls. The replaceable roll being connectable to a temperature control device operated with a tempering capacity that depends on the type of the replaced roll.
In accordance with a feature of the invention, the process further includes switching over the operating mode of the temperature control device with the replacement of the replaceable roll.
According to another feature of the invention, the process can include positioning a scraper device on the replaceable roll depending on the type of the replaced roll.
According to still another feature of the present invention, the temperature control device is operated with oil.
The present invention is directed to a calender that includes a roll stack, composed of end rolls and at least one intermediate roll positioned between the end rolls, having an end nip formed between an end roll and the at least one intermediate roll. The at least one intermediate roll includes a replaceable roll, which is selectively a hard roll or soft roll. The calender includes a device for holding the at least one replaceable roll, and each replaceable roll has a connection arrangement for a temperature control device, in which the temperature control devices correspond to each other geometrically.
According to a feature of the present invention, the temperature control device can be structured and arranged for heating a hard roll and for removing heat from a soft roll.
In accordance with another feature of the invention, the replaceable rolls may include switchover devices structured and arranged to convert the temperature control device to an appropriate operating mode for the selected replaceable roll.
According to still another feature of the instant invention, the at least one replaceable roll includes a hard roll.
Further, the calender can also include a scraper arrangement structured and arranged at the replaceable roll, the operating parameters of which are adjustable depending on the selected replaceable roll.
Moreover, a web run is provided through both end nips, and each end nip may be formed by an end roll and a replaceable roll, and the replaceable roll can be selectively changed from a hard roll to a soft roll. The web run runs through all the nips of the calender, and all the calender nips, with the exception of the end nips, are opened.
The invention is directed to a calender including end rolls composed of soft rolls, and a plurality of intermediate rolls located between the end rolls. Intermediate rolls arranged adjacent the end rolls are replaceable rolls that are selectively hard or soft rolls, and the replaceable rolls include connection arrangements for temperature control device. A temperature control device is structured and arranged to heat the replaceable roll when selected as a hard roll and to remove heat from the replaceable roll when selected as a soft roll.
According to a feature of the present invention, the calender further includes devices for preventing positional movements of the replaceable rolls.
In accordance with another feature of the invention, the temperature control device can include a switchover device that changes the temperature control device from heating to heat removal. The replaceable rolls may include identifier elements readable by the temperature control device to identify the replaceable rolls as either hard rolls or soft rolls.
Moreover, all nips, with the exception of the end nips can be opened. The web can be guided to only the end nips. Further, the web may be guided through all of the nips.
The replaceable rolls are soft rolls, whereby the end nips are composed of two soft rolls. Alternatively, the replaceable rolls are hard rolls, whereby the end nips are composed of a soft roll and hard roll.
The present invention is directed to a process of calendering a web in a multi-roll calender, in which the multi-roll calender includes end rolls and a plurality of intermediate rolls located between the end rolls, in which the intermediate rolls adjacent the end rolls are hard rolls. The process includes opening the nips, replacing the hard roll with a soft roll, and calendering the web in only at least one end nip formed by the end roll and the adjacent soft roll.
In accordance with still yet another feature of the present invention, the process can also include determining the replacement of the hard roll, and changing a temperature control device coupled to the replaced soft roll from a heating mode to a heat removal mode.
Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure and the accompanying drawing.
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 exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:
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.
Nips 14-22 are embodied or formed between the rolls 2-11, through which nips a paper web 23 can be guided. The nips 14-17 and 19-22 are hereby embodied or formed as “soft” nips that are formed between a hard heated roll 3, 5, 8, 10 and a soft roll 2, 4, 6, 7, 9, 11 with an elastic surface covering. The paper web 23 is glazed in these nips 14-17, 19-22. A changeover nip 18 which is formed by two soft rolls 6, 7 is provided in order to allow both sides of the paper web to rest against hard rolls 3, 5 or 8, 10.
The calender 1 is thus embodied as a “classic” supercalender that is “normally” operated in the operating mode according to
Such an increase in smoothness of the paper web 23 can be undesirable. It is therefore also possible, as discernible with the operating mode according to
In order to make it possible for the pressurization of the paper web 23 to take place only in the nip 22, but not in the other nips 14-21, the last intermediate roll 10 can be fixed or held firmly. To this end, an adjustable stop 26 is provided which is embodied or formed, e.g., as a hydraulically activated piston-cylinder arrangement and which acts on an end 27 of a two-armed lever 28, at the other end 29 of which the last intermediate roll 10 is arranged.
Due to the stop 26, the last intermediate roll 10 can be held such that a pressurization of the web 23 is possible in the nip 22 through the lower end roll 11 without the other rolls 2-9 having to be used to support the last intermediate roll 10. Accordingly, the other nips 14-21 can remain opened as shown in
Even a glazing of this type can cause too great an increase of smoothness. A replacement roll 30 is therefore provided for the calender 1, which, as can be seen in
The soft roll 30 is likewise cleaned by the scraper arrangement 24, however, it is provided that the operating parameters of the scraper arrangement 24 may be changed and/or adapted to the surface of the soft roll 30. In particular the contact pressure of the scraper blade 25 is reduced and, if necessary, the pitch angle is also changed.
The soft roll 30 is also held by the stop 26 so that a pressurization of the paper web 23 is possible in the last nip 22 via the roll 11 without the other rolls having to rotate as well.
The soft roll 30 is also installed at the position of the last intermediate roll 10 (
The upper soft intermediate roll 31 is also provided with a scraper arrangement 32 that cleans the surface of the soft intermediate roll 31 in operation.
The replacement of a hard roll 3, 10 by a soft roll 31, 30 is easily possible because the two rolls have the same connection geometry, as shown in diagrammatic form in
In
A valve 37 is provided to connect a feed connection 38 of the roll 10, which is connected to the connection 44, either to the heating device 33 or to the cooling device 34. The connection is made depending on the type of roll that is installed at the position of the lower intermediate roll 10. If it is a hard roll 10, as shown in
The roll 10 is provided with a probe 39 that can be scanned by a sensor of a control device 40. The control device 40 controls the valve 37 on the one hand and the scraper arrangement 24 on the other hand, i.e., the control device 40 adjusts the contact pressure and the pitch angle of the scraper blade 25 depending on the type of roll.
As can be seen in
The representation of
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 an exemplary embodiment, 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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 003 715 | Jan 2004 | DE | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4332191 | Kankaanpaa | Jun 1982 | A |
| 4375188 | Leiviska | Mar 1983 | A |
| 4960046 | Anstötz et al. | Oct 1990 | A |
| 5947017 | Hartwich et al. | Sep 1999 | A |
| 6248215 | Cramer et al. | Jun 2001 | B1 |
| Number | Date | Country |
|---|---|---|
| 3107709 | Aug 1982 | DE |
| 20200584 | May 2002 | DE |
| 0822289 | Feb 1998 | EP |
| 0890676 | Jan 1999 | EP |
| Number | Date | Country | |
|---|---|---|---|
| 20050178278 A1 | Aug 2005 | US |
