System and method for switching a calendering device from a hard-nip calendering mode to a soft-nip calendering mode
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- VOITH PATENT GMBH
- Filing Date
- 2024-08-15
- Publication Date
- 2026-06-10
Smart Images
Figure EP2024072961_27032025_PF_FP_ABST
Abstract
Description
[0001] System and method for converting a calendering device from a hard-nip calendering operation to a soft-nip calendering operation
[0002] The invention relates to a system, a deflection compensation roll, a method and a computer program product for converting a calendering device from a hard-nip calendering operation to a soft-nip calendering operation and vice versa.
[0003] In the paper industry, calenders are used after the papermaking process to achieve the desired final quality of the paper web, especially uniform thickness and surface smoothness. The paper web passes through at least one nip between rollers that apply pressure and temperature to the paper web to compact and smooth the paper fibers, creating a uniform and smooth surface structure. Depending on the paper grade, different technical properties, especially gloss and smoothness, are optimized in the calender. Different calender types are used to achieve the desired smoothness and glazing.
[0004] But calenders are also used in other industries to refine materials. In the textile industry, calendering involves passing the textile fabric between two or more heated rollers, which exert pressure and heat on the fabric to achieve a smoother surface, better gloss, and a more appealing appearance.
[0005] A hard-nip calender consists of two rolls, usually made of cast iron, that exert high pressure on the material web as it passes through the nip. The pressure exerted by the rolls in a hard-nip calender is relatively high, resulting in significant densification and smoothing of the material surface. In papermaking, the hard-nip calender serves several purposes. It can improve the smoothness, gloss, and printability of the paper surface, making the paper more suitable for high-quality printing applications. It can also increase the opacity and bulk of the paper and reduce caliper variations. The term "hard-nip" refers to the firm and considerable pressure applied during calendering, which distinguishes it from other calendering processes that use softer rolls or lower pressure.The specific configuration and operating parameters of a hard-nip calender can vary depending on the desired material properties.
[0006] An example of a hard-nip calender is the EcoCal Hard Calender from Voith, which features at least one treatment nip with two hard-surfaced rolls. A heated roll ensures even temperature distribution. The counter roll is a deflection-compensating roll that allows for control of the line force in the cross direction.
[0007] In contrast to a hard-nip calender, which exerts high pressure on the material web, a soft-nip calender exerts less pressure on the material web and results in a gentler calendering process, offering high flexibility in achieving the desired material properties for various applications. The rolls used in a soft-nip calender are typically coated with elastic materials such as polymers or composites to create a softer and more compressible surface. The lower pressure and the use of softer rolls in a soft-nip calender result in gentler compaction and smoothing of the material surface compared to a hard-nip calender.The primary purpose of using a soft-nip calender is to improve the surface smoothness, gloss, and printability of the material without compromising thickness and bulk, resulting in a higher-quality and more visually appealing product. Soft-nip calendering is particularly advantageous for certain paper grades, such as those used in printing and writing applications where a smooth and uniform surface is desired. It can also be used for specialty papers that require specific surface properties, such as labels or packaging materials.
[0008] An example of a soft nip calender is the EcoCal Soft Calender from Voith.
[0009] The EcoCal Soft calender consists of at least one treatment nip with two rolls, with at least one roll featuring a surface with a lower hardness. A heated roll ensures a heated surface and even temperature distribution. The counter roll is a deflection-compensating roll that allows for control of the line force in the cross direction and is covered with a fiber composite material. EcoCal Soft calenders are used as standard calenders for a wide range of paper and board grades.
[0010] DE 10 2019 124 244 A1 discloses a calender for the pressure treatment of a web of material, comprising a first roll with a first roll axis and a second roll with a second roll axis, wherein the first and second rolls can be interlaced about an interlacing axis perpendicularly intersecting the first and second roll axes. A bearing device for at least one of the rolls comprises at least one rocker with a roll holder, wherein the rocker is mounted on the calender frame so as to be adjustable in an adjustment direction.
[0011] EP 1 394 424 B1 discloses a deflection-compensating roll with a rotating roll shell, a rotationally fixed yoke axially penetrating the roll shell, and support elements arranged between the yoke and the roll shell. The inner side of the roll shell and / or the support surfaces of the support elements facing this shell inner side, or a strip arranged between the support elements and the shell inner side, are provided with a plastic coating.
[0012] The invention is based on the object of creating possibilities with which a calendering device can be converted quickly, safely and reliably from a hard-nip calendering operation to a soft-nip calendering operation and vice versa with a high degree of flexibility.
[0013] This object is achieved according to the invention with regard to a system by the features of patent claim 1, with regard to a deflection compensating roll by the features of claim 10, with regard to a method by the features of claim 14, and with regard to a computer program product by the features of claim 15. The further claims relate to preferred embodiments of the invention.
[0014] The present invention enables a quick and cost-effective conversion from hard-nip calendering to soft-nip calendering, as the calendering device and the deflection compensation rolls are equipped with corresponding receiving and insert elements, allowing easy replacement of a hard deflection compensation roll with a soft deflection compensation roll, and vice versa, without complex adjustment and rewiring. Furthermore, an identification element enables automatic detection of the respective roll type, allowing the corresponding operating parameters for converting the calendering device from hard-nip calendering to soft-nip calendering to be automatically set by a control unit.By simply changing the calender's operating mode, the requirements for processing different materials, especially different paper grades, can be met flexibly and cost-effectively. This allows resource utilization to be optimized and the overall efficiency of paper production to be improved.
[0015] The invention provides a system for converting a calendering device from a hard-nip calendering operation with at least one heating roll and at least one hard deflection compensation roll to a soft-nip calendering operation with at least the heating roll and at least one soft deflection compensation roll, and vice versa. During calendering in hard-nip calendering operation, a material web, in particular a paper web, is typically guided through the nip between the rotating heating roll and the rotating hard deflection compensation roll. During calendering in soft-nip calendering operation, a material web, in particular a paper web, is typically guided through the nip between the rotating heating roll and the rotating soft deflection compensation roll.The system comprises at least one sensor, a control unit for controlling and regulating various operating parameters such as pressure, temperature, and roll speed, a drive system, and other components of the calendering device. The calendering device comprises at least one receiving element for receiving either the hard deflection compensation roll or the soft deflection compensation roll, wherein the hard deflection compensation roll and the soft deflection compensation roll are interchangeable. The hard deflection compensation roll comprises at least one insert element for insertion into the receiving element and at least one first identification element. The soft deflection compensation roll comprises at least one insert element for insertion into the receiving element and at least one second identification element.The sensor is designed to detect the first identification element or the second identification element after a soft or hard deflection compensation roll has been inserted into the receiving element, to identify the type of the respective deflection compensation roll based on the detected identification element, and to forward the information about the type of the respective deflection compensation roll to the control unit. The control unit is designed to execute a control program depending on the detected identification element (37, 47) or the identified type of deflection compensation roll (30, 40) in order to operate the calendering device with the retrieved operating parameters in hard-nip calendering mode or in soft-nip calendering mode.
[0016] For example, two variants of the control program can be stored in the control unit. If the sensor transmits the information "Hard deflection compensation roll is installed!" to the control unit, it executes the "Hard nip calendering" variant. If the sensor transmits the information "Soft deflection compensation roll is installed!" to the control unit, it executes the "Soft nip calendering" variant.
[0017] In a further embodiment, the control unit can comprise a database in which data on values or characteristic maps of the operating parameters in hard-nip calendering and soft-nip calendering are stored. Depending on the detected identification element or the identified type of deflection compensation roll, the control unit can retrieve the data with the operating parameters for hard-nip calendering or soft-nip calendering from the database and operate the control program for the calendering device with the retrieved operating parameters in hard-nip calendering or soft-nip calendering.
[0018] Regardless of the specific design of the control unit, a system according to aspects of the invention ensures that the calendering device is always operated in the correct operating mode. Manual adjustment or reprogramming is not necessary, thus avoiding the risk of malfunction and, consequently, potential damage to the calendering device.
[0019] One advantageous application of such a system is a plant for the production of uncoated, wood-free paper (WFU). Such machines typically produce various paper grades. The majority of the production volume is in the low- to medium-quality range. Only a small portion of the production volume consists of demanding grades. For these demanding grades, the use of a soft-nip calender is necessary to achieve the desired surface qualities. Therefore, soft-nip calenders are provided in existing plants, although a hard-nip calender would generally be sufficient for most grades.
[0020] However, this is detrimental to the upkeep and maintenance of the system. While the rolls in the hard-nip calender can be operated for about a year before the surface needs to be reground, the rolls in the soft-nip calender wear out significantly faster and sometimes require reground after just six weeks.
[0021] With a system according to aspects of the invention, the calender can now be adapted to the grades produced. For most of the time, the system is operated with the hard-nip calender. Only for grades with high quality requirements is the soft-nip calender switched over. Especially for applications such as the production of uncoated wood-free papers, calendering systems with exactly one calendering nip are usually used. This calendering nip is formed by the heating roll and a deflection compensation roll.
[0022] In a further development, it is provided that the identification element is designed as a mechanical and / or optical and / or electronic identification element.
[0023] In an advantageous embodiment, it is provided that the mechanical identification element comprises a pin and / or a pin and is arranged at a predetermined position on the bending compensation roller, wherein the position of the identification element of the hard bending compensation roller differs from the position of the soft bending compensation roller in order to form a unique identification code in each case.
[0024] In a further embodiment, it is provided that the sensor is designed as an electrical contact which can be activated by the connection to an identification element.
[0025] In particular, the mechanical identification element is arranged on the end face of the deflection compensation roll. In advantageous embodiments, the mechanical identification element can be attached to the circumference of the roll end face. Since a deflection compensation roll typically has a rotating roll shell rotating around a static yoke, the roll end face can be designed to be static. This makes it ideal for attaching a mechanical identification element.
[0026] Advantageously, a first scraper is provided for the hard deflection compensation roller and a second scraper is provided for the soft deflection compensation roller, wherein the first scraper and the second scraper are each detachably connectable to a scraper beam.
[0027] Typically, the hard deflection compensation roll and the soft deflection compensation roll have different diameters. This is particularly pronounced in calendering systems that only have one calendering nip. Therefore, it is often difficult to provide a single doctor blade that can be brought into the correct position simply by adjusting it after changing from a hard to a soft deflection compensation roll, or vice versa. Therefore, it is advantageous to provide two doctor blades, allowing a suitable one to be installed depending on the type of deflection compensation roll installed.
[0028] In a further embodiment, the first scraper and the second scraper each comprise at least one identification element that uniquely represents the identity of the first scraper and the second scraper, respectively.
[0029] For example, first fastening means for fastening the first scraper and second fastening means for fastening the second scraper can be provided, wherein these are designed in particular such that the first fastening means are unsuitable for fastening the second scraper and the second fastening means are unsuitable for fastening the first scraper.
[0030] For example, the identification elements of the two scrapers can be realized via specific drilling patterns, whereby the drilling pattern of the first scraper differs from the drilling pattern of the second scraper.
[0031] Fastening devices, e.g., in the form of suitable holes, etc., can then be provided on the corresponding scraper beam. These are arranged such that the first scraper can only be fastened using the first holes and the second scraper only using the second holes. In this way, malfunctions can be avoided here as well. Alternatively, the identification element of the first scraper and the second scraper is designed as a mechanical identification element that can be detected by a second sensor, wherein the second sensor is designed as an electrical contact that can be activated by the connection to the identification element of the first scraper or the second scraper.
[0032] In a further development, it is provided that at least one further roller can be inserted into the receiving element of the calendering device, wherein the further roller also comprises at least one identification element for identifying the roller type, and wherein the operating parameters for the further roller are stored in the database and can be retrieved for the operation of the calendering device with the further roller.
[0033] According to a second aspect, the invention provides a deflection compensation roll for use in a calendering device. The deflection compensation roll comprises at least one identification element for uniquely identifying the roll type of a hard deflection compensation roll, a soft deflection compensation roll, or at least one other roll.
[0034] In a further development, it is provided that the identification element is designed as a mechanical and / or optical and / or electronic identification element.
[0035] In an advantageous embodiment, it is provided that the mechanical identification element comprises a pin and / or a pin and is arranged at a predetermined position on the bending compensation roller, wherein the position of the identification element of the hard bending compensation roller differs from the position of the identification element of the soft bending compensation roller in order to form a unique identification code in each case.
[0036] In a further embodiment, the mechanical identification element is arranged on the end face of the deflection compensation roll. According to a third aspect, the invention provides a method for converting a calendering device from a hard-nip calendering operation with at least one heating roll and at least one hard deflection compensation roll to a soft-nip calendering operation with at least the heating roll and at least one soft deflection compensation roll, and vice versa. During calendering in hard-nip calendering operation, a material web, in particular a paper web, is guided through the nip between the rotating heating roll and the rotating hard deflection compensation roll. During calendering in soft-nip calendering operation, a material web, in particular a paper web, is guided through the nip between the rotating heating roll and the rotating soft deflection compensation roll.The calendering device comprises at least one receiving element for receiving either the hard deflection compensation roll or the soft deflection compensation roll. The hard deflection compensation roll comprises at least one insert element for insertion into the receiving element and at least one first identification element. The soft deflection compensation roll comprises at least one insert element for insertion into the receiving element and at least one second identification element. The method comprises the following method steps:
[0037] - Inserting the hard deflection compensation roll or the soft deflection compensation roll into the receiving element of the calendering device;
[0038] - detecting the first or second identification element from a sensor and identifying the roller type as a hard or soft deflection compensation roller;
[0039] - Forwarding the information about the type of the respective deflection compensation roller to a control unit;
[0040] - Execution of a control program by the control unit depending on the detected identification element or the identified type of deflection compensation roll in order to operate the calendering device in hard-nip calendering mode or soft-nip calendering mode. - Operation of the calendering device in hard-nip calendering mode or soft-nip calendering mode.
[0041] According to a fourth aspect, the invention provides a computer program product comprising executable program code that carries out the method according to the third aspect.
[0042] The invention is explained in more detail below with reference to embodiments shown in the drawing.
[0043] It shows:
[0044] Figure 1 is a schematic representation of a system according to the invention;
[0045] Figure 2 shows a flow chart to explain the individual process steps of the process according to the invention;
[0046] Figure 3 is a schematic representation of a computer program product.
[0047] Additional features, aspects and advantages of the invention or embodiments thereof will become apparent from the detailed description taken in conjunction with the claims.
[0048] Fig. 1 schematically shows a system 100 for converting a calendering device 200 from a hard-nip calendering operation with at least one heating roll 20 and at least one hard deflection compensation roll 30 to a soft-nip calendering operation with at least the heating roll 20 and at least one soft deflection compensation roll 40 for calendering a material, such as in particular a paper web. During calendering in hard-nip calendering operation, a material web is guided through the nip between the rotating heating roll 20 and the rotating hard deflection compensation roll 30, which are pressed against each other with controlled pressure. In soft-nip calendering operation, a material web is guided through the nip between the rotating heating roll 20 and the rotating soft deflection compensation roll 40.
[0049] In hard-nip calendering, at least two rolls with hard surfaces are used. The heating roll 20 ensures uniform temperature distribution, and the counter roll is a hard deflection compensation roll 30, which allows for control of the line force in the transverse direction.
[0050] The soft-nip calendering system also includes the heating roll 20, which ensures a heated surface and even temperature distribution. The counter roll is now a soft deflection compensation roll 40, which allows for control of the line force in the cross direction and is covered with a fiber composite material. The soft-nip calendering system is the standard calendering system for a wide variety of paper and board grades and is therefore used more frequently than the hard-nip calendering system.
[0051] The heating roller 20 typically consists of a cylindrical core material with high thermal conductivity, such as steel or aluminum. To improve heat transfer, the surface of the heating roller 20 can be additionally provided with a special coating. This coating can be made of materials such as rubber, polymers, or ceramics, which enable good heat transfer and even temperature distribution. The heating roller 20 is connected to a heating system that supplies the heat energy. This heating system can take various forms, such as electrical heating elements or steam lines, which heat the heating roller 20 to the desired operating temperature. The heated surface of the heating roller 20 comes into contact with the material during calendering. As the material is passed over the heating roller 20, heat exchange takes place between the hot surface of the heating roller 20 and the material.This can, for example, make a paper web softer, develop viscoelastic properties, and exhibit better formability. Furthermore, the heat can help cure certain materials such as plastics or coatings or improve their structural properties. The temperature of the heating roller 20 can be precisely adjusted to ensure that the material acquires the desired properties without being damaged or overheated. The heating roller 20 in a calender thus plays an essential role in the thermal modification of a paper web and enables the control and optimization of processes such as smoothing, coating, and drying.
[0052] A deflection compensation roller 30, 40 in a calender serves to create a homogeneous roller gap and thus, in particular, to compensate for unevenness in the heating roller 20. As the material is passed between the heating roller 20 and the deflection compensation roller 30, 40, the deflection compensation roller 30, 40 adapts to the unevenness of the heating roller 20 and thereby compensates for the uneven pressure. This compensation function achieves a more uniform surface and thickness of the processed material. For this purpose, the deflection compensation roller 30, 40 is usually equipped internally with actuators that compensate for the deformation across the width of the roller, thus creating a homogeneous roller gap. The deflection compensation roller 30, 40 thus enables more precise control and quality improvement in the processing of paper, textiles, and other materials.
[0053] According to the invention, the heating roller 20 is designed as a hard roller for operation in both hard-nip calendering mode and soft-nip calendering mode. The hard deflection compensation roller 30 has a hard plastic shell or a metal shell, e.g., made of steel, cast iron, or with a hard metal coating, while the soft deflection compensation roller 40 has a soft roller shell made of a composite or polymer material.
[0054] For the purposes of the invention, a roller with a surface hardness of more than 50 ShoreD on the Shore Durometer scale, in particular 60 ShoreD and more, is referred to as a "hard roller." Hard rollers, especially those with a metallic shell, can also have significantly higher hardness values in the range of 70 ShoreD, 80 ShoreD, or more. In contrast, a "soft roller" has a surface hardness of less than 50 ShoreD. The hardness of soft rollers can also be significantly lower, for example, 40 ShoreD, 30 ShoreD, or less.
[0055] According to the invention, the conversion of the calendering device 200 from a hard-nip calendering operation to a soft-nip calendering operation and vice versa is carried out by exchanging the hard bending compensation roll 30 for the soft bending compensation roll 40, while the heating roll 20 remains in the calendering device 200.
[0056] In particular, it is provided that the connection of the deflection compensation roll 30, 40 to the calendering device 200 is made via a connecting device, which is designed in particular as a plug-in and / or clamp connection. For this purpose, the calendering device 200 has a receiving element 220 and the deflection compensation roll 30, 40 has an insert element 32, 42, in particular on at least one roll end face. The receiving element 220 is designed to releasably receive the insert element 32, 42 in order to hold or fasten the deflection compensation roll 30, 40. The receiving element 220 and the insert element 32, 34 are designed in such a way that a precise alignment and positioning of the respective deflection compensation roll 30, 40 in the calendering device 200 is enabled and a secure, precise and functional connection can be established.
[0057] In particular, the receiving element 220 is designed similarly to a socket, and the insert element 32, 42 is designed similarly to a plug. Like a socket, the receiving element 220 has recesses for receiving plug elements of the insert element 32, 42 for fastening and supporting the deflection compensation roller 30, 40. Furthermore, the receiving element 220 has internal electrical contacts connected to electrical lines. These electrical contacts are designed to accommodate electrical contact pins of the insert element 32, 42 in order to establish a safe and reliable electrical connection. The diameters of the soft deflection compensation roller 40 and the hard deflection compensation roller 30 are generally different, since the soft deflection compensation roller 40 has an additional coating that increases the diameter. The required diameter compensation is achieved via the bearings of the respective deflection compensation roller 30, 40.Additionally, support elements can be used if required.
[0058] Replacing the soft deflection compensation roller 40 with the hard deflection compensation roller 30, and vice versa, is generally performed manually. However, an automated device, such as a robotic device, can also be provided for this purpose, allowing automatic interchange of the two deflection compensation rollers 30, 40. A storage device is provided for storing the unused deflection compensation roller 30, 40.
[0059] According to the invention, automatic detection of the deflection compensation roll type currently installed in the calendering device 200 is provided by means of at least one identification element 37, 47. Specific operating parameters for the hard deflection compensation roll 30 and the soft deflection compensation roll 40 are stored in a database 550, which is connected to a control unit 500. These operating parameters relate, for example, to the loading force or pressure applied to the roll gap, but also to the control of the actuators within the deflection compensation roll 30, 40 and the temperature of the heating roll 20. The type of deflection compensation roll 30, 40 installed is detected, and the correct operating program for operation in hard-nip calendering mode or soft-nip calendering mode is automatically applied.
[0060] To distinguish the respective roller type, at least one first identification element 37 is attached to the hard deflection compensation roller 30 and at least one second identification element 47 is attached to the soft deflection compensation roller 40. In particular, the identification element 37, 47 is designed as a mechanical identification element, e.g., as a pin or stud, which, depending on the deflection compensation roller type (hard / soft), is attached at different locations on a deflection compensation roller 30, 40 or differs in its shape (round / square). In particular, it is provided that the mechanical identification element 37, 47 is arranged on the roller end face of the deflection compensation roller 30, 40 or is integrated into the insert element 32, 42.
[0061] However, it can also be provided that the identification element is designed as an electronic identification element with an identification code, for example as a transponder with an RFID chip or an NFC chip (Near Field Communication), or as an optical identification element, for example as a barcode or QR code.
[0062] A sensor 300 is provided on the calendering device 200, which is designed to detect the first and second identification elements 37, 47 and to identify the deflection compensation roll type. The sensor 300 is designed, in particular, as an electrical contact that is closed by the engagement of a mechanical identification element 37, 47. If the identification elements 37, 47 are arranged at different positions on the deflection compensation roll 37, 47 depending on the deflection compensation roll type, the type of deflection compensation roll can be determined by closing different electrical contacts. By closing the respective electrical contacts, the type of deflection compensation roll is detected in a correspondingly designed circuit of the sensor 300.
[0063] The mechanical identification elements 37, 47 and the sensor 300 designed as an electrical contact are cost-effective, characterized by high reliability and are insensitive to contamination.
[0064] The sensor 300 can also be designed as a camera for detecting the mechanical and / or optical identification elements 37, 47. In the case of a transponder with an RFID or NFC chip, the sensor 300 contains a readout unit with which the identification code can be read. After the deflection compensation roll type has been detected by the sensor 300, the operating parameters for the detected deflection compensation roll type are retrieved from the database 550 and transmitted to the control unit 500. The control unit 500 can then start the hard-nip calendering operation or the soft-nip calendering operation with the corresponding operating parameters.
[0065] Sensor 300 and control unit 500 preferably comprise a processor to execute or implement the method according to the invention or a step of the method according to the invention. In the context of the invention, a processor can be, for example, a microprocessor or an electronic circuit.
[0066] The database 550 can be implemented as non-volatile storage such as a hard disk or data carrier, or, for example, as a removable memory module. The database 550 can also be integrated into a cloud computing infrastructure. A cloud computing infrastructure offers the advantage of fast computing power and high cost efficiency, as it eliminates the need for large upfront investments in hardware and infrastructure. Furthermore, the cloud computing infrastructure facilitates integration with other systems and enables the creation of networked and scalable architectures.
[0067] In a further development of the invention, it can be provided that additional roller types are used in the calendering device 200. These rollers are also marked with roller-specific identification elements. In the case of mechanical identification elements, these are attached to the roller in a type-specific manner, allowing for unambiguous identification.
[0068] A scraper for a calender roll is a mechanical device for cleaning the roll surface. The rolls of a calender are in direct contact with the material being processed, such as paper, textiles, or other materials. During calendering, residues, dirt, contaminants, or material deposits can accumulate on the roll surface. It is important to clean the rolls regularly, as dirt accumulation or material residues can impair the quality of the processed material and negatively impact the calendering result. The use of a scraper ensures that the rolls remain free of contamination and guarantees consistently high quality of the processed material. The scraper comprises a sharp scraper blade and is attached to a scraper beam, which is positioned near the roll so that it covers the entire width of the roll.As the roller rotates, the scraper is moved across the surface, effectively removing any contaminants or residues present on the surface. The scraper gently scrapes the deposits from the roller surface without damaging the roller.
[0069] To achieve optimal cleaning results, scrapers are manufactured for various roller types in different configurations and materials. A clean roller surface ensures a smooth and high-quality calendering process.
[0070] According to the invention, a first scraper 52 for hard-nip calendering operation and a second scraper 57 for soft-nip calendering operation are provided, which can be interchangeably fastened to a scraper beam. In order to achieve optimal effectiveness, both the type and the installation position of the scrapers for soft-nip and hard-nip operation can differ. The first scraper 52 is therefore provided with a different identification element than the second scraper 57. These identification elements can be designed as different bore patterns. The scraper beam of the calendering device 200 has connection points, in particular with first bores for the first scraper 52 and with second bores for the second scraper 57. The bores are ideally arranged such that the first scraper 52 can only be fastened with the first bores and the second scraper 57 only with the second bores. In this way, incorrect operation can be avoided here too.The scraper bar, equipped with appropriate connecting elements, enables a quick exchange of the first scraper 52 with the second scraper 57 and vice versa. Automatic recognition of the scraper type prevents the use of an unsuitable scraper 52, 57 that does not fit the replaced deflection compensation roller 30, 40.
[0071] Fig. 2 shows the method steps for converting a calendering device 200 from a hard-nip calendering operation with at least one heating roll 20 and at least one hard deflection compensation roll 30 to a soft-nip calendering operation with at least the heating roll 20 and at least one soft deflection compensation roll 40.
[0072] In a step S10, the hard bending compensation roll 40 or the soft bending compensation roll 30 is inserted into a receiving element 220 of the calender device 200.
[0073] In a step S20, the first or second identification element 37, 47 is detected by a sensor 300 and the roller type is identified as a hard bending compensation roller 30 or as a soft bending compensation roller 40.
[0074] In a step S30, the information about the type of the respective deflection compensation roller 30, 40 is forwarded to a control unit 500.
[0075] In a step S40, data with the operating parameters for the hard-nip calender operation or the soft-nip calender operation are retrieved from a database 550, wherein the operating parameters include values or characteristic maps with respect to the pressure, the temperature, the speed of the rolls 20, 30, 40, a drive system and other components of the calender device 200.
[0076] In a step S50, the calendering device 200 is operated with the retrieved operating parameters in hard-nip calendering mode or in soft-nip calendering mode. Fig. 3 schematically illustrates a computer program product 900 comprising executable program code 950 configured to carry out the method according to the first aspect of the present invention.
[0077] The present invention enables a quick and cost-effective conversion from hard-nip calendering to soft-nip calendering, as the calendering device and the deflection compensation rolls are equipped with corresponding receiving and insert elements, allowing easy replacement of a hard deflection compensation roll with a soft deflection compensation roll, and vice versa, without complex adjustment and rewiring. Furthermore, an identification element enables automatic detection of the respective roll type, allowing the corresponding operating parameters for converting the calendering device from hard-nip calendering to soft-nip calendering to be automatically set by a control unit.By simply changing the calender's operating mode, the requirements for processing different materials, especially different paper grades, can be met flexibly and cost-effectively. This allows resource utilization to be optimized and the overall efficiency of paper production to be improved.
[0078] Reference symbol heating roller hard deflection compensation roller insert element identification element hard deflection compensation roller insert element identification element first scraper second scraper system calender device receiving element first sensor second sensor control unit database computer program product program code
Claims
Patent claims 1. A system (100) for converting a calendering device (200) from a hard-nip calendering operation with at least one heating roller (20) and at least one hard deflection compensation roller (30) to a soft-nip calendering operation with at least the heating roller (20) and at least one soft deflection compensation roller (40), and vice versa, comprising at least one sensor (300), a control unit (500) for controlling and regulating various operating parameters such as pressure, temperature, speed of the rollers (20, 30, 40), a drive system, and other components of the calendering device (200); wherein the calendering device (200) comprises at least one receiving element (220) for receiving either the hard deflection compensation roller (30) or the soft deflection compensation roller (40), wherein the hard deflection compensation roller (30) and the soft deflection compensation roller (40) are interchangeable;wherein the hard deflection compensation roller (30) comprises at least one insert element (32) for insertion into the receiving element (220) and at least one first identification element (37); wherein the soft deflection compensation roller (40) comprises at least one insert element (42) for insertion into the receiving element (220) and at least one second identification element (47); wherein the sensor (300) is designed to detect the first identification element (37) or the second identification element (47) after a soft or hard deflection compensation roller (30, 40) has been inserted into the receiving element (220), to identify the type of the respective deflection compensation roller (30, 40) based on the detected identification element (37, 47), and to forward the information about the type of the respective deflection compensation roller (30, 40) to the control unit (500);wherein the control unit (500) is designed to execute a control program depending on the detected identification element (37, 47) or the identified type of deflection compensation roll (30, 40) in order to operate the calendering device (200) in hard-nip calendering mode or in soft-nip calendering mode; 2. System (100) according to claim 1, wherein the identification element (37, 47) is designed as a mechanical and / or optical and / or electronic identification element.
3. System (100) according to claim 2, wherein the mechanical identification element (37, 47) comprises a pin and / or a pin and is arranged at a predetermined position on the deflection compensation roller (30, 40), wherein the position of the identification element (37) of the hard deflection compensation roller (30) differs from the position of the soft deflection compensation roller (40) in order to form a unique identification code in each case.
4. System (100) according to claim 2 or 3, wherein the sensor (300) is designed as an electrical contact which can be activated by the connection to an identification element (37, 47).
5. System (100) according to claim 3 or 4, wherein the mechanical identification element (37, 47) is arranged on the roller end face of the deflection compensation roller (30, 40).
6. System (100) according to one of claims 1 to 5, wherein a first scraper (52) is provided for the hard deflection compensation roll (30) and a second scraper (57) is provided for the soft deflection compensation roll (40), and wherein the first scraper (52) and the second scraper (57) are detachably connectable to a scraper beam.
7. System (100) according to claim 6, wherein the first scraper (52) and the second scraper (57) each comprise at least one identification element which uniquely represents the identity of the first scraper (52) or the second scraper (57) and can be detected by a second sensor (40).
8. System (100) according to one of claims 6 or 7, wherein first fastening means for fastening the first scraper (52) and second fastening means for fastening the second scraper (57) are provided, wherein these are designed such that the first fastening means are unsuitable for fastening the second scraper (57), and the second fastening means are unsuitable for fastening the first scraper (52).
9. System (100) according to one of claims 1 to 8, wherein the hard deflection compensation roller (30) has a surface hardness of more than 50 ShoreD on the Shore Durometer scale, in particular of 60 ShoreD and / or the soft deflection compensation roller (40) has a surface hardness of less than 50 ShoreD, in particular less than 40 ShoreD.
10. System (100) according to one of the preceding claims, characterized in that the calendering device (200) has exactly one calendering nip, which is formed by the heating roller (20) and a bending compensation roller (30, 40).
11. A bending compensation roll (30, 40) for use in a calendering device (200), wherein the bending compensation roll (30, 40) comprises at least one identification element (37, 47) for uniquely identifying the roll type of a hard bending compensation roll (30), a soft bending compensation roll (40) or at least one further roll.
12. Bending compensation roller (30, 40) according to claim 11, wherein the identification element (37, 47) is designed as a mechanical and / or optical and / or electronic identification element.
13. Bending compensation roller (30, 40) according to claim 12, wherein the mechanical identification element (37, 47) comprises a pin and / or a pin and is arranged at a predetermined position on the bending compensation roller (30, 40), wherein the position of the identification element (37) of the hard bending compensation roller (30) from the position of the identification element (47) of the soft bending compensation roller (40) in order to form a unique identification code in each case.
14. A bending compensation roller (30, 40) according to claim 13, wherein the mechanical identification element (37, 47) is arranged on the roller end face of the bending compensation roller (30, 40).
15. A method for converting a calendering device (200) from a hard-nip calendering operation with at least one heating roll (20) and at least one hard deflection compensation roll (30) to a soft-nip calendering operation with at least the heating roll (20) and at least one soft deflection compensation roll (40) and vice versa, wherein the calendering device (200) comprises at least one receiving element (220) for receiving either the hard deflection compensation roll (30) or the soft deflection compensation roll (40); wherein the hard deflection compensation roll (30) comprises at least one insert element (32) for insertion into the receiving element (220) and at least one first identification element (37); wherein the soft deflection compensation roll (40) comprises at least one insert element (42) for insertion into the receiving element (220) and at least one second identification element (47); comprising the method steps: - inserting (S10) the hard bending compensation roller (40) or the soft bending compensation roller (30) into the receiving element (220) of the calendering device (200); - detecting (S20) the first or second identification element (37, 47) by a sensor (300) and identifying the roller type as a hard bending compensation roller (30) or as a soft bending compensation roller (40); - forwarding (S30) the information about the type of the respective bending compensation roller (30, 40) to a control unit (500); - Execution of a control program by the control unit (500) depending on the detected identification element (37, 47) or the identified type of deflection compensation roll (30, 40) in order to operate the calendering device (200) in hard-nip calendering operation or in soft-nip calendering operation. - Operating (S50) the calendering device (200) in hard-nip calendering mode or in soft-nip calendering mode.
16. A computer program product (900) comprising executable program code (950) that carries out the method of claim 15.