EP0933472B1 - Process for operating a calender and calender - Google Patents
Process for operating a calender and calender Download PDFInfo
- Publication number
- EP0933472B1 EP0933472B1 EP99101366A EP99101366A EP0933472B1 EP 0933472 B1 EP0933472 B1 EP 0933472B1 EP 99101366 A EP99101366 A EP 99101366A EP 99101366 A EP99101366 A EP 99101366A EP 0933472 B1 EP0933472 B1 EP 0933472B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- roller
- stack
- rolls
- drive
- calender
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
- D21G1/00—Calenders; Smoothing apparatus
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
- D21G1/00—Calenders; Smoothing apparatus
- D21G1/0006—Driving arrangements
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- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
- D21G1/00—Calenders; Smoothing apparatus
- D21G1/002—Opening or closing mechanisms; Regulating the pressure
- D21G1/0026—Arrangements for maintaining uniform nip conditions
- D21G1/0033—Arrangements for maintaining uniform nip conditions by offsetting the roll axes horizontally
Definitions
- the invention relates to a method for operating a calender according to the preamble of claim 1 and to a calender according to the preamble of claim 8.
- rollers form a number of working gaps, which are each delimited by a hard roller and an elastic roller, and an alternating gap, which is delimited by two elastic rollers.
- a separate drive is provided for each roller.
- the auxiliary drives provided in addition to the main drive serve to bring the peripheral speed of the respective roller to web speed, so that the roller package can be closed at paper insertion speed.
- US 3 044 392 A describes a calender with a roll stack which has a plurality of middle rolls between two end rolls. The lower end roller is driven. A paper web running through the calender takes the other rolls with it by friction. In order to prevent the rollers from bending, the rollers are alternately offset from the central plane of the roller stack.
- the invention has for its object to provide a new way of influencing the calender.
- the compressive stress cross profile can be influenced by a specific bending of a roll, several rolls or all rolls transversely to the central plane of the stack. Depending on the degree of deflection, small to large corrections can be achieved within the large permissible range.
- the deflection of one roller can be adapted to the deflection of the neighboring roller, so that there is a high degree of uniformity. This applies in particular in the first and last working nip, because a reaction force that cannot be undercut acts on the end rolls, which leads to a deflection that is only dependent on the rigidity of the roll.
- the influence of the compressive stress according to claim 2 is based on the novel finding that when the bending lines of adjacent rolls are spread, the pressure is relieved not in the middle of the web but in the edge regions of the web.
- the features of claim 3 indicate how the drives can be controlled to easily relieve or load the edge area.
- regulation of the compressive stress cross profile is also advantageous.
- the drives are part of the control loop.
- Claim 5 offers the advantageous possibility that the shear forces in the web are approximately zero, which presupposes, however, that the rollers are bent.
- a paper produced in this way has a higher tear strength.
- roller bearings designed as roller bearings have a longer service life because they are constantly under load.
- the embodiment according to claim 7 leads to a very uniform compressive stress cross profile.
- the object is achieved according to the invention by the features of claim 8.
- Center rolls with a slenderness ratio above 10 are very easy to bend and therefore reach the limit of the permissible range if there is no countermeasure by the drive torques.
- the permissible range is exceeded if the bending lines of adjacent rolls are spread so far that the roll ends stand out from one another.
- the slenderness ratio is defined as the ratio of length to diameter.
- a preferred degree of slenderness is between 12 and 16 according to claim 9 and approximately 14 according to claim 10.
- the two end rollers are said to have a lower degree of slenderness. Their inevitable deflection is therefore kept smaller, so that the adaptation of the next roller to the deflection of the end roller requires only a slight deflection.
- the calender can be arranged off-line according to claim 12. Such a calender that is independent from the paper machine runs at a much slower speed than an in-line calender connected to a paper machine. For such an off-line calender, a single drive on a roll that dragged all other rolls by friction was considered sufficient and therefore the effects of the single drive could not be used.
- the diameter of at least one central roller should be a maximum of 100 cm. This upper limit applies to a calender with a width of 10 m and more.
- a calender 1 is arranged as an off-line calender between an unwinding station 2 and a winding station 3. However, it could also connect to the output of a paper machine as an in-line calender.
- the calender has a vertical stack 4 of eight rollers 5 to 12, namely an upper roller 5 and a lower roller 12, both of which can be designed as zone-controlled bending adjustment rollers, and six middle rollers 6 to 11.
- Four rollers 5, 7, 10 and 12 a hard metallic surface and four rollers 6, 8, 9 and 11 an elastic plastic covering.
- the rollers 7 and 10 can be heated by means of superheated steam.
- the bearing block 13 of the top roller 5 is firmly attached to the stand 14 of the calender 1.
- the bearing blocks 15 of the center rollers 6 to 11 are supported by levers 16 which are rotatable about pivot axes 17 fastened to the stand 14.
- the bearing block 18 for the lower roller 12 is held on a vertical guide 19 and can be pressed upwards by means of a hydraulic cylinder 20, so that there is a sufficient line load in the working gaps 21 of the stack.
- the hydraulic cylinder 20 is lowered, the center rollers 6 to 11 also follow it until the associated levers 16 come to rest against a stop 22 and all the nips are open.
- the levers 16 are loaded by force transducers 23, with which the loads and weights hanging on the levers can be fully or partially compensated.
- a paper web 24 is guided through the nips with the aid of guide rollers 25.
- a measuring device 26 is provided, which measures a parameter of the paper web 24, namely over the entire width, be it by a reciprocating measuring element or by several measuring elements distributed over the width.
- parameters come, for example, gloss, smoothness, thickness or the like. into consideration.
- Each of the eight rollers 5 to 12 has its own drive 27, the drive torque of which is predetermined by a control device 28, as is indicated schematically by the outputs A5 to A12.
- the control device 28 has further outputs, in particular an output B20, which determines the pressure for the hydraulic cylinder 20, outputs B5 / 12, which the pressure in the bending adjustment devices of the end rollers 5 and 12 determine outputs B23, which determine the pressure in the force transmitters 23, and outputs B6 / 10, which determine the supply of the heat carrier in the heatable rollers 7 and 10.
- Numerous inputs E1 are used to enter data that are essential for paper finishing, in particular the setpoints of the desired paper parameters.
- Other inputs, such as input E 26, are used to enter measured actual values, for example smoothness, gloss or thickness.
- F N denotes that force which is required to overcome the calendering resistance. It serves to overcome the compression of the elastic roller cover as well as the elastic and plastic parts of the paper forming. F N changes from nip to nip with the physical properties (eg density and smoothness), ie not only with the roll load characteristic.
- M R denotes the frictional moments of the roller bearings and, if applicable, of scrapers and sealing heads (rotary inlets for heating or cooling media). The latter can significantly exceed the bearing friction. In the case of bending adjustment rollers, the friction from the oil flow between the fixed axis and the rotating jacket and the hydrostatic oil gaps or the sealing strips on S rollers dominate.
- F U is the force to be applied by the rollers to the paper web 24, which is necessary to overcome the calendering resistance and, if applicable, any web tension ⁇ B Z that may be present.
- the specified reaction force F R1 which cannot be made zero, can be calculated from the circumferential forces F U1 , the friction moments M R1 and the diameter D 1 of the roller 5.
- the differences in the circumferential forces result in reaction forces for the center rolls, which can be changed within a certain range by changing the drive torque of the individual drives. It is important that the reaction forces F R are responsible for the deflection, that is, the lateral deflection of the rolls.
- a control device 28 is provided with which these drive torques can be set for each individual drive in order to influence the compressive stress cross profile in this way.
- a high degree of uniformity of the compressive stress results if the deflection of the top middle roller 6 from the center plane of the stack is adapted to the unavoidable deflection of the top roller 5. Even if the deflection of the upper roller 5 is only slight, an adaptation of the bending line of the roller 6 brings about an improvement in the compressive stress cross profile.
- a certain reaction force and deflection is desired anyway so that the roller bearings are constantly subjected to a certain load and therefore have a long service life.
- the center rollers 6 to 11 had a slenderness degree (length / diameter) of about 14.
- the examples shown can be varied in many ways without departing from the basic idea of the invention.
- the calender 1 can also be used in in-line operation.
- the number of rollers can vary, with the preferred values being between four and eight.
- the end rollers 5 and 12 can also be designed as elastic rollers and adjacent to the hard center rollers.
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- Manufacturing Of Magnetic Record Carriers (AREA)
Abstract
Description
Die Erfindung bezieht sich auf ein Verfahren zum Betrieb eines Kalanders gemäß dem Oberbegriff des Anspruchs 1 und auf einen Kalander gemäß dem Oberbegriff des Anspruchs 8.The invention relates to a method for operating a calender according to the preamble of claim 1 and to a calender according to the preamble of claim 8.
Bei einem bekannten Kalander dieser Art (DE 295 18 424) sind fünf und mehr Walzen, vorzugsweise 8 Walzen, übereinander angeordnet. Die Walzen bilden eine Anzahl von Arbeitsspalten, die je durch eine harte Walze und eine elastische Walze begrenzt sind, und einen Wechselspalt, der durch zwei elastische Walzen begrenzt ist. Für jede Walze ist ein eigener Antrieb vorgesehen. Die zusätzlich zum Hauptantrieb vorgesehenen Hilfsantriebe dienen dazu, die Umfangsgeschwindigkeit der jeweiligen Walze auf Bahngeschwindigkeit zu bringen, so daß das Walzenpaket bei Papier-Einführgeschwindigkeit geschlossen werden kann.In a known calender of this type (DE 295 18 424) five or more rolls, preferably 8 rolls, are arranged one above the other. The rollers form a number of working gaps, which are each delimited by a hard roller and an elastic roller, and an alternating gap, which is delimited by two elastic rollers. A separate drive is provided for each roller. The auxiliary drives provided in addition to the main drive serve to bring the peripheral speed of the respective roller to web speed, so that the roller package can be closed at paper insertion speed.
US 3 044 392 A beschreibt einen Kalander mit einem Walzenstapel, der zwischen zwei Endwalzen mehrere Mittelwalzen aufweist. Die untere Endwalze ist angetrieben. Eine durch den Kalander laufende Papierbahn nimmt die übrigen Walzen durch Reibung mit. Um eine Ausbiegung der Walzen zu verhindern, sind die Walzen abwechselnd zur Mittelebene des Walzenstapels versetzt angeordnet.US 3 044 392 A describes a calender with a roll stack which has a plurality of middle rolls between two end rolls. The lower end roller is driven. A paper web running through the calender takes the other rolls with it by friction. In order to prevent the rollers from bending, the rollers are alternately offset from the central plane of the roller stack.
Der Erfindung liegt die Aufgabe zugrunde, eine neue Beeinflussungsmöglichkeit des Kalanders anzugeben.The invention has for its object to provide a new way of influencing the calender.
Diese Aufgabe wird verfahrensmäßig durch die Merkmale des Anspruchs 1 gelöst.This object is achieved procedurally by the features of claim 1.
Durch eine gezielte Ausbiegung einer Walze, mehrerer Walzen oder aller Walzen quer zur Mittelebene des Stapels läßt sich das Druckspannungsquerprofil beeinflussen. Innerhalb des großen Zulässigkeitsbereichs lassen sich je nach Grad der Durchbiegung kleinere bis größere Korrekturen erzielen. Insbesondere kann die Ausbiegung einer Walze der Ausbiegung der Nachbarwalze angepaßt werden, so daß sich ein hohes Maß an Gleichmäßigkeit ergibt. Dies gilt insbesondere im ersten und letzten Arbeitsspalt, weil an den Endwalzen eine nicht unterschreitbare Reaktionskraft angreift, die zu einer lediglich von der Steifigkeit der Walze abhängigen Ausbiegung führt.The compressive stress cross profile can be influenced by a specific bending of a roll, several rolls or all rolls transversely to the central plane of the stack. Depending on the degree of deflection, small to large corrections can be achieved within the large permissible range. In particular, the deflection of one roller can be adapted to the deflection of the neighboring roller, so that there is a high degree of uniformity. This applies in particular in the first and last working nip, because a reaction force that cannot be undercut acts on the end rolls, which leads to a deflection that is only dependent on the rigidity of the roll.
Die Druckspannungs-Beeinflussung nach Anspruch 2 beruht auf der neuartigen Erkenntnis, daß bei einer Spreizung der Biegelinien benachbarter Walzen eine Entlastung nicht etwa in der Bahnmitte, sondern in den Randbereichen der Bahn erfolgt.The influence of the compressive stress according to claim 2 is based on the novel finding that when the bending lines of adjacent rolls are spread, the pressure is relieved not in the middle of the web but in the edge regions of the web.
Die Merkmale des Anspruchs 3 geben an, wie die Antriebe angesteuert werden können, um auf einfache Weise Entlastung oder Belastung des Randbereichs zu erzielen.The features of claim 3 indicate how the drives can be controlled to easily relieve or load the edge area.
Gemäß Anspruch 4 ist auch eine Regelung des Druckspannungsquerprofils von Vorteil. Hierbei sind die Antriebe Teil des Regelkreises.According to claim 4, regulation of the compressive stress cross profile is also advantageous. The drives are part of the control loop.
Anspruch 5 bietet die vorteilhafte Möglichkeit, daß die Scherkräfte in der Bahn annähernd Null sind, was allerdings voraussetzt, daß eine Ausbiegung der Walzen vorhanden ist. Ein so hergestelltes Papier besitzt eine höhere Reißfestigkeit.Claim 5 offers the advantageous possibility that the shear forces in the web are approximately zero, which presupposes, however, that the rollers are bent. A paper produced in this way has a higher tear strength.
Die Forderung des Anspruchs 6, den Kleinstwert der Reaktionskräfte ungleich Null zu halten, bringt den Vorteil, daß die als Wälzlager ausgelegten Walzenlager eine höhere Lebensdauer haben, weil sie ständig unter Belastung stehen.The requirement of claim 6, to keep the minimum value of the reaction forces not equal to zero, has the advantage that the roller bearings designed as roller bearings have a longer service life because they are constantly under load.
Die Ausgestaltung nach Anspruch 7 führt zu einem sehr gleichmäßigen Druckspannungsquerprofil.The embodiment according to claim 7 leads to a very uniform compressive stress cross profile.
Konstruktiv wird die Aufgabe erfindungsgemäß durch die Merkmale des Anspruchs 8 gelöst. Mittelwalzen mit einem Schlankheitsgrad über 10 sind sehr leicht biegbar und geraten daher über die Grenze des Zulässigkeitsbereichs, wenn keine Gegensteuerung durch die Antriebsmomente erfolgt. Der Zulässigkeitsbereich wird überschritten, wenn die Biegelinien benachbarter Walzen so weit gespreizt sind, daß sich die Walzenenden voneinander abheben. Der Schlankheitsgrad ist definiert als Verhältnis von Länge zum Durchmesser. Solche schlanken Walzen sind von großem Vorteil, weil sie wegen der stärkeren Krümmung zu einer höheren Druckspannung im Spalt führen und weil sie ein geringeres Gewicht haben.In terms of construction, the object is achieved according to the invention by the features of claim 8. Center rolls with a slenderness ratio above 10 are very easy to bend and therefore reach the limit of the permissible range if there is no countermeasure by the drive torques. The permissible range is exceeded if the bending lines of adjacent rolls are spread so far that the roll ends stand out from one another. The slenderness ratio is defined as the ratio of length to diameter. Such slim rolls are of great advantage because they lead to a higher compressive stress in the gap because of the greater curvature and because they have a lower weight.
Ein bevorzugter Schlankheitsgrad liegt gemäß Anspruch 9 zwischen 12 und 16 und gemäß Anspruch 10 etwa bei 14.A preferred degree of slenderness is between 12 and 16 according to claim 9 and approximately 14 according to claim 10.
Die beiden Endwalzen sollen dagegen gemäß Anspruch 11 einen geringeren Schlankheitsgrad haben. Ihre unvermeidliche Ausbiegung wird daher kleiner gehalten, so daß auch die Anpassung der nächsten Walze an die Durchbiegung der Endwalze nur eine geringe Ausbiegung erfordert.In contrast, the two end rollers are said to have a lower degree of slenderness. Their inevitable deflection is therefore kept smaller, so that the adaptation of the next roller to the deflection of the end roller requires only a slight deflection.
Des weiteren kann der Kalander nach Anspruch 12 off-line angeordnet sein. Ein solcher Kalander, der unabhängig von der Papiermaschine arbeitet, läuft mit erheblich geringerer Geschwindigkeit als ein In-line-Kalander, der an eine Papiermaschine angeschlossen ist. Für einen solchen Off-line-Kalander hatte man einen einzigen Antrieb an einer Walze, die alle übrigen Walzen durch Reibung mitschleppte, für ausreichend angesehen und konnte daher die Wirkungen des Einzelantriebs nicht nutzen.Furthermore, the calender can be arranged off-line according to claim 12. Such a calender that is independent from the paper machine runs at a much slower speed than an in-line calender connected to a paper machine. For such an off-line calender, a single drive on a roll that dragged all other rolls by friction was considered sufficient and therefore the effects of the single drive could not be used.
Gemäß Anspruch 13 sollte der Durchmesser wenigstens einer Mittelwalze maximal 100 cm sein. Dieser obere Grenzwert gilt für einen Kalander mit einer Breite von 10 m und mehr.According to claim 13, the diameter of at least one central roller should be a maximum of 100 cm. This upper limit applies to a calender with a width of 10 m and more.
Die Erfindung wird nachstehend anhand der Zeichnung näher erläutert. Es zeigen:
- Fig. 1
- schematisch einen erfindungsgemäß Kalander und
- Fig. 2
- die Kräfteverhältnisse in den oberen drei Walzen des Stapels.
- Fig. 1
- schematically a calender according to the invention and
- Fig. 2
- the balance of forces in the top three rollers of the stack.
Ein Kalander 1 ist als Off-line-Kalander zwischen einer Abwickelstation 2 und einer Aufwickelstation 3 angeordnet. Er könnte aber auch als In-line-Kalander an den Ausgang einer Papiermaschine anschließen. Der Kalander besitzt einen vertikalen Stapel 4 aus acht Walzen 5 bis 12, nämlich einer Oberwalze 5 und einer Unterwalze 12, die beide als zonenweise gesteuerte Biegeeinstellwalzen ausgebildet sein können, und sechs Mittelwalzen 6 bis 11. Vier Walzen 5, 7, 10 und 12 haben eine harte metallische Oberfläche und vier Walzen 6, 8, 9 und 11 einen elastischen Kunststoffbelag. Die Walzen 7 und 10 sind mittels Heißdampf beheizbar.A calender 1 is arranged as an off-line calender between an unwinding station 2 and a winding station 3. However, it could also connect to the output of a paper machine as an in-line calender. The calender has a vertical stack 4 of eight rollers 5 to 12, namely an upper roller 5 and a lower roller 12, both of which can be designed as zone-controlled bending adjustment rollers, and six middle rollers 6 to 11. Four rollers 5, 7, 10 and 12 a hard metallic surface and four rollers 6, 8, 9 and 11 an elastic plastic covering. The rollers 7 and 10 can be heated by means of superheated steam.
Der Lagerblock 13 der Oberwalze 5 ist fest am Ständer 14 des Kalanders 1 angebracht. Die Lagerblöcke 15 der Mittelwalzen 6 bis 11 werden von Hebeln 16 getragen, die um am Ständer 14 befestigte Schwenkachsen 17 drehbar sind. Der Lagerblock 18 für die Unterwalze 12 ist an einer Vertikalführung 19 gehalten und kann mittels eines Hydraulikzylinders 20 nach oben gedrückt werden, so daß sich in den Arbeitsspalten 21 des Stapels eine ausreichende Streckenlast ergibt. Beim Absenken des Hydraulikzylinders 20 folgen diesem auch die Mittelwalzen 6 bis 11, bis die zugehörigen Hebel 16 an einem Anschlag 22 zur Anlage kommen und sämtliche Walzenspalte offen stehen. Die Hebel 16 werden durch Kraftgeber 23 belastet, mit denen die an den Hebeln hängenden Lasten und Gewichte ganz oder teilweise kompensiert werden können.The bearing block 13 of the top roller 5 is firmly attached to the stand 14 of the calender 1. The bearing blocks 15 of the center rollers 6 to 11 are supported by levers 16 which are rotatable about pivot axes 17 fastened to the stand 14. The bearing block 18 for the lower roller 12 is held on a vertical guide 19 and can be pressed upwards by means of a hydraulic cylinder 20, so that there is a sufficient line load in the working gaps 21 of the stack. When the hydraulic cylinder 20 is lowered, the center rollers 6 to 11 also follow it until the associated levers 16 come to rest against a stop 22 and all the nips are open. The levers 16 are loaded by force transducers 23, with which the loads and weights hanging on the levers can be fully or partially compensated.
Eine Papierbahn 24 wird mit Hilfe von Leitwalzen 25 durch die Walzenspalte geführt. Ausgangsseitig ist eine Meßvorrichtung 26 vorgesehen, die einen Parameter der Papierbahn 24 mißt, und zwar über die gesamte Breite, sei es durch ein hin- und hergehendes Meßelement oder durch mehrere über die Breite verteilte Meßelemente. Als Parameter kommen beispielsweise Glanz, Glätte, Dikke o.dgl. in Betracht.A paper web 24 is guided through the nips with the aid of guide rollers 25. On the output side, a measuring device 26 is provided, which measures a parameter of the paper web 24, namely over the entire width, be it by a reciprocating measuring element or by several measuring elements distributed over the width. As parameters come, for example, gloss, smoothness, thickness or the like. into consideration.
Jede der acht Walzen 5 bis 12 besitzt einen eigenen antrieb 27, dessen Antriebsmoment durch eine Steuervorrichtung 28 vorgegeben wird, wie dies schematisch durch die Ausgänge A5 bis A12 angegeben ist. Die Steuervorrichtung 28 besitzt weitere Ausgänge, insbesondere einen Ausgang B20, der den Druck für den Hydraulikzylinder 20 bestimmt, Ausgänge B5/12, welche den Druck in den Biegeeinstellvorrichtungen der Endwalzen 5 und 12 bestimmen, Ausgänge B23, welche den Druck in den Kraftgebern 23 bestimmen, und Ausgänge B6/10, welche die Zufuhr des Wärmeträgers in den beheizbaren Walzen 7 und 10 bestimmen.Each of the eight rollers 5 to 12 has its own drive 27, the drive torque of which is predetermined by a control device 28, as is indicated schematically by the outputs A5 to A12. The control device 28 has further outputs, in particular an output B20, which determines the pressure for the hydraulic cylinder 20, outputs B5 / 12, which the pressure in the bending adjustment devices of the end rollers 5 and 12 determine outputs B23, which determine the pressure in the force transmitters 23, and outputs B6 / 10, which determine the supply of the heat carrier in the heatable rollers 7 and 10.
Zahlreiche Eingänge E1 dienen der Eingabe von Daten, die für die Papierveredlung wesentlich sind, insbesondere die Sollwerte der gewünschten Papierparameter. Weitere Eingänge, wie der Eingang E 26, dienen der Eingabe von gemessenen Istwerten, beispielsweise der Glätte, Glanz oder Dicke.Numerous inputs E1 are used to enter data that are essential for paper finishing, in particular the setpoints of the desired paper parameters. Other inputs, such as input E 26, are used to enter measured actual values, for example smoothness, gloss or thickness.
In Fig. 2 bezeichnet FN diejenige Kraft, die zur Überwindung des Kalandrierwiderstandes erforderlich ist. Sie dient der Überwindung der Kompression des elastischen Walzenbezuges sowie den elastischen und plastischen Anteilen der Papierumformung. FN ändert sich mit den physikalischen Eigenschaften (z.B. der Dichte und Glätte) von Spalt zu Spalt, d.h. nicht nur mit der Walzenlast-Kennlinie.In Fig. 2, F N denotes that force which is required to overcome the calendering resistance. It serves to overcome the compression of the elastic roller cover as well as the elastic and plastic parts of the paper forming. F N changes from nip to nip with the physical properties (eg density and smoothness), ie not only with the roll load characteristic.
MR bezeichnet die Reibungsmomente der Walzenlager und gegebenenfalls von Schabern und Dichtköpfen (Dreheinführungen für Heiz- oder Kühlmedien). Letztere können die Lagerreibungen deutlich übersteigen. Bei Biegeeinstellwalzen dominiert die Reibung aus der Ölströmung zwischen feststehender Achse und rotierendem Mantel sowie den hydrostatischen Ölspalten beziehungsweise den Dichtleisten bei S-Walzen.M R denotes the frictional moments of the roller bearings and, if applicable, of scrapers and sealing heads (rotary inlets for heating or cooling media). The latter can significantly exceed the bearing friction. In the case of bending adjustment rollers, the friction from the oil flow between the fixed axis and the rotating jacket and the hydrostatic oil gaps or the sealing strips on S rollers dominate.
FU ist die von den Walzen auf die Papierbahn 24 aufzubringende Kraft, die zur Überwindung des Kalandrierwiderstandes und gegebenenfalls einer etwa vorhandenen Bahnzugkraft ΔBZ erforderlich ist.F U is the force to be applied by the rollers to the paper web 24, which is necessary to overcome the calendering resistance and, if applicable, any web tension ΔB Z that may be present.
In Fig. 2 ist angenommen, daß die Kräfte FU je zur Hälfte auf die den Walzenspalt bildenden Walzen aufgeteilt werden. Da die Kalandrierwiderstände und damit die Kräfte FN von oben nach unten abnehmen, trifft dies auch für die Umfangskräfte FU zu.In Fig. 2 it is assumed that the forces F U are each divided equally between the rollers forming the nip. Since the calendering resistances and thus the forces F N decrease from top to bottom, this also applies to the circumferential forces F U.
Aus den Umfangskräften FU1, den Reibungsmomenten MR1 und dem Durchmesser D1 der Walze 5 läßt sich die angegebene Reaktionskraft FR1 berechnen, die nicht zu Null gemacht werden kann. Aus den Differenzen der Umfangskräfte ergeben sich für die Mittelwalzen Reaktionskräfte, die durch Änderung des Antriebsmoments der Einzelantriebe in einem gewissen Rahmen änderbar sind. Wichtig ist es, daß die Reaktionskräfte FR für die Durchbiegung, also die seitliche Ausbiegung der Walzen verantwortlich sind.The specified reaction force F R1 , which cannot be made zero, can be calculated from the circumferential forces F U1 , the friction moments M R1 and the diameter D 1 of the roller 5. The differences in the circumferential forces result in reaction forces for the center rolls, which can be changed within a certain range by changing the drive torque of the individual drives. It is important that the reaction forces F R are responsible for the deflection, that is, the lateral deflection of the rolls.
Erfindungsgemäß ist eine Steuervorrichtung 28 vorgesehen, mit der diese Antriebsmomente für jeden Einzelantrieb einstellbar sind, um auf diese Weise das Druckspannungsquerprofil zu beeinflussen. Ein hohes Maß an Gleichmäßigkeit der Druckspannung ergibt sich, wenn die Ausbiegung der obersten Mittelwalze 6 aus der Mittelebene des Stapels der unvermeidbaren Ausbiegung der Oberwalze 5 angepaßt ist. Auch wenn die Ausbiegung der Oberwalze 5 nur gering sein sollte, bringt eine Anpassung der Biegelinie der Walze 6 eine Verbesserung des Druckspannungsquerprofil mit sich.According to the invention, a control device 28 is provided with which these drive torques can be set for each individual drive in order to influence the compressive stress cross profile in this way. A high degree of uniformity of the compressive stress results if the deflection of the top middle roller 6 from the center plane of the stack is adapted to the unavoidable deflection of the top roller 5. Even if the deflection of the upper roller 5 is only slight, an adaptation of the bending line of the roller 6 brings about an improvement in the compressive stress cross profile.
In anderen Fällen, beispielsweise bei einer zu großen Kantenpressung, kann es interessant sein, die Biegelinien benachbarter Walzen, also deren Mittellinien, zu spreizen, um auf diese Weise die Druckspannungen an den Rändern der Bahn zu vermindern.In other cases, for example when the edge pressure is too great, it may be interesting to spread the bending lines of adjacent rolls, that is to say their center lines, in order in this way to reduce the compressive stresses at the edges of the web.
Eine andere günstige Betriebsweise, mit der besonders zugfestes Papier erzielt werden kann, sieht vor, daß auf die Bahn keine Scherkräfte ausgeübt werden. Auch dies setzt eine gewisse Ausbiegung der Mittelwalzen voraus.Another cheap mode of operation with which particularly high-tensile paper can be achieved provides that no shear forces are exerted on the web. This also requires a certain deflection of the middle rolls.
Eine gewisse Reaktionskraft und Ausbiegung ist ohnehin erwünscht, damit die Walzenlager ständig eine gewisse Belastung erfahren und daher eine hohe Lebensdauer besitzen.A certain reaction force and deflection is desired anyway so that the roller bearings are constantly subjected to a certain load and therefore have a long service life.
Bei einer bevorzugten Ausführungsform hatten die Mittelwalzen 6 bis 11 einen Schlankheitsgrad (Länge/Durchmesser) von etwa 14. Durch entsprechende Einstellung der Antriebsmomente der Einzelantriebe 27 wird zwangsweise eine zu starke Verbiegung der Walzen verhindert, so daß die Druckspannungswerte im Zulässigkeitsbereich bleiben und insbesondere kein Abheben der Walzen voneinander an ihren Enden auftritt.In a preferred embodiment, the center rollers 6 to 11 had a slenderness degree (length / diameter) of about 14. By appropriately adjusting the drive torques of the individual drives 27, excessive bending of the rollers is inevitably prevented, so that the compressive stress values remain within the permissible range and, in particular, do not lift off of the rollers occurs from each other at their ends.
Außerdem ist es möglich, gezielt für eine Friktion im Walzenspalt zu sorgen.It is also possible to specifically create friction in the nip.
Von den dargestellten Beispielen kann in vielfacher Hinsicht abgewichen werden, ohne den Grundgedanken der Erfindung zu verlassen. Insbesondere kann der Kalander 1 auch im In-line-Betrieb verwendet werden. Die Zahl der Walzen kann variieren, wobei die bevorzugten Werte zwischen vier und acht liegen. Hierbei können auch die Endwalzen 5 und 12 als elastische Walzen ausgelegt und harten Mittelwalzen benachbart sein.The examples shown can be varied in many ways without departing from the basic idea of the invention. In particular, the calender 1 can also be used in in-line operation. The number of rollers can vary, with the preferred values being between four and eight. Here, the end rollers 5 and 12 can also be designed as elastic rollers and adjacent to the hard center rollers.
Claims (13)
- Method of operating a calender for a web material such as paper, having a stack of rolls which has at least one intermediate roll between two end rolls, which rolls each have their own drive and can be loaded in the direction of the stack, characterized in that, in at least one operating nip, at least one intermediate roll can specifically be deflected out of the mid-plane of the stack of rolls, and the reaction forces required for this are produced by appropriate adjustment of the drive torques.
- Method according to Claim 1, characterized in that, to reduce the compressive stress in the edge regions and/or to increase the compressive stress in the centre of the web in at least one operating nip, the difference in the deflection of the rolls bounding the operating nip is increased.
- Method according to Claim 1 or 2, characterized in that, to relieve the load on the edge region, one drive takes over the leading rôle in transmitting the drive torque, while, to load the edge region, the drive torques are distributed more uniformly.
- Method according to one of Claims 1 to 3, characterized by control of the transverse compressive stress profile, in which a web parameter is monitored over the web width and, in the event of a control deviation, at least part of the correction is effected by changing the drive torques.
- Method according to one of Claims 1 to 4, characterized in that the drive torques are selected such that the reaction forces of adjacent rolls, and therefore their deflection, are not equal to zero and the shear forces in the web are approximately zero.
- Method according to one of Claims 1 to 5, characterized in that the drive torques are selected such that the smallest value of the reaction forces is not equal to zero.
- Method according to one of Claims 1 to 6, characterized in that an intermediate roll adjacent to the end roll is deflected out of the plane of the stack towards the same side as the end roll.
- Calender for a web material such as paper, having a stack of rolls which has at least one intermediate roll between two end rolls, which rolls each have their own drive and can be loaded in the direction of the stack, in particular for implementing the method according to one of Claims 1 to 7, characterized in that at least one intermediate roll (6 to 11) has a slenderness ratio of more than 10, and a control apparatus (28) for supplying the drive torques (A5 to A12) is provided, which keeps the reaction forces (FR) on this roll and therefore its deflection from the mid-plane of the stack in the permissible range.
- Calender according to Claim 8, characterized in that the slenderness ratio is 12 to 16.
- Calender according to Claim 8 or 9, characterized in that the slenderness ratio is about 14.
- Calender according to one of Claims 8 to 10, characterized in that the two end rolls (5, 12) of the stack (4) have a slenderness ratio ≤ 10.
- Calender according to one of Claims 8 to 11, characterized in that it can be arranged off-line.
- Calender according to one of Claims 1 to 12, characterized in that the diameter of at least one intermediate roll (6 to 11) is at most 100 cm.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19803323 | 1998-01-29 | ||
| DE19803323A DE19803323C2 (en) | 1998-01-29 | 1998-01-29 | Process for influencing a web material, such as paper, and calender for carrying out the process |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0933472A2 EP0933472A2 (en) | 1999-08-04 |
| EP0933472A3 EP0933472A3 (en) | 2000-05-10 |
| EP0933472B1 true EP0933472B1 (en) | 2004-03-31 |
Family
ID=7855953
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP99101366A Expired - Lifetime EP0933472B1 (en) | 1998-01-29 | 1999-01-26 | Process for operating a calender and calender |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US6234075B1 (en) |
| EP (1) | EP0933472B1 (en) |
| AT (1) | ATE263277T1 (en) |
| CA (1) | CA2260508A1 (en) |
| DE (2) | DE19803323C2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7096779B2 (en) | 1998-03-17 | 2006-08-29 | Eduard Küsters Maschinenfabrik GmbH & Co. KG | Calender arrangement |
| US20030126998A1 (en) * | 1998-03-17 | 2003-07-10 | Eduard Kusters Maschinenfabrik Gmbh & Co. Kg | Calender arrangement |
| DE19811474A1 (en) * | 1998-03-17 | 1999-09-23 | Kuesters Eduard Maschf | Vertical arrangement of glazing rollers employed in paper manufacture |
| DE10158910B4 (en) * | 2001-11-30 | 2005-12-22 | Voith Paper Patent Gmbh | Method and calender for satinizing a paper or board web |
| US7079263B2 (en) * | 2002-06-14 | 2006-07-18 | Kimberly-Clark Worldwide, Inc. | Method and apparatus for on-line log diameter measurement and closed-loop control |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE252151C (en) * | ||||
| US3044392A (en) * | 1959-07-10 | 1962-07-17 | Kimberly Clark Co | Papermaking machine |
| US3331313A (en) * | 1965-09-24 | 1967-07-18 | Black Clawson Co | Calender stacks having transverse pressure sensing and adjustment means |
| DE3735438C1 (en) * | 1987-10-20 | 1989-05-18 | Kleinewefers Gmbh | Process for operating a calender and calender for carrying out this process |
| DE29521610U1 (en) * | 1995-03-09 | 1997-11-20 | Voith Sulzer Finishing GmbH, 47803 Krefeld | Calender for the treatment of a paper web |
| DE19508352B4 (en) * | 1995-03-09 | 2005-07-21 | Voith Paper Patent Gmbh | Calender for the treatment of a paper web |
| DE29518424U1 (en) * | 1995-11-21 | 1996-03-14 | Voith Sulzer Finishing GmbH, 47803 Krefeld | Calender in a paper or coating machine |
| DE19633671C2 (en) * | 1996-08-21 | 1999-03-11 | Voith Sulzer Finishing Gmbh | calender |
| DE19650576C2 (en) * | 1996-12-06 | 2001-02-15 | Kuesters Eduard Maschf | calender |
-
1998
- 1998-01-29 DE DE19803323A patent/DE19803323C2/en not_active Expired - Fee Related
-
1999
- 1999-01-26 AT AT99101366T patent/ATE263277T1/en not_active IP Right Cessation
- 1999-01-26 EP EP99101366A patent/EP0933472B1/en not_active Expired - Lifetime
- 1999-01-26 DE DE59908983T patent/DE59908983D1/en not_active Expired - Fee Related
- 1999-01-27 CA CA002260508A patent/CA2260508A1/en not_active Abandoned
- 1999-01-28 US US09/238,576 patent/US6234075B1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE19803323C2 (en) | 2003-06-05 |
| ATE263277T1 (en) | 2004-04-15 |
| EP0933472A2 (en) | 1999-08-04 |
| DE19803323A1 (en) | 1999-08-05 |
| US6234075B1 (en) | 2001-05-22 |
| DE59908983D1 (en) | 2004-05-06 |
| CA2260508A1 (en) | 1999-07-29 |
| EP0933472A3 (en) | 2000-05-10 |
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