Calender and method for controlling such a calender

Abstract

A calender includes a rotatable roller, and a belt co-acting with the roller with a determined belt pressure. At least one material for feeding through the calender is situated between the roller and the belt for a determined contact time during throughfeed through the calender. The calender also includes means for heating the fluid and/or the roller, control means for controlling the heating means and/or the belt pressure and/or the contact time, and at least one first temperature sensor for measuring the temperature of an outer periphery of the roller and at least one second temperature sensor for measuring the temperature of the fluid. The control means are configured to control the heating means and/or the belt pressure and/or the contact time on the basis of the measured outer periphery temperature and the measured fluid temperature. A set with a plurality of such calenders and a method for controlling such a calender.

1 . A calender, comprising:
 a rotatable roller, which roller is hollow and thereby defines an internal space which is configured to be filled at least partially with a heatable fluid;   a belt, co-acting with the roller, with a determined belt pressure, wherein at least one material for feeding through the calender is situated between the roller and the belt for a determined contact time during throughfeed through the calender;   heating means for heating the fluid and/or the roller, which heating means are disposed in the internal space;   one or more control means for controlling the heating means and/or the belt pressure and/or the contact time,   at least one first temperature sensor for measuring the temperature of an outer periphery of the roller, and   at least one second temperature sensor for measuring the temperature of the fluid,   wherein the one or more control means are configured to control the heating means and/or the belt pressure and/or the contact time on the basis of the measured outer periphery temperature and the measured fluid temperature.   
     
     
         2 . The calender according to  claim 1 , comprising a database in which at least one of the following data is stored, periodically:
 the measured outer periphery temperature of the roller;   a or the measured fluid temperature;   the contact time;   the belt pressure;   a number of revolutions of the roller since the start of a calendering process;   at least one property of the at least one material being fed through the calender;   at least one property of a transfer paper optionally being fed through the calender;   an ambient temperature;   an air humidity;   which calender is used;   a power of drive means of the calender; and   at least one property of a belt of the calender,   and wherein the control means are further configured to control the heating means and/or the belt pressure and/or the contact time on the basis of at least one of the data contained in the database.   
     
     
         3 . The calender according to  claim 2 , wherein the control means are configured to determine on the basis of at least periodically measured outer periphery temperatures and periodically measured fluid temperatures of a plurality of prior calendering processes and on the basis of at least the at least one property of the same material how the heating means and/or the belt pressure and/or the contact time must be set in order to obtain a desired outer periphery temperature in the current calendering process, and to control the heating means and/or the belt pressure and/or the contact time in the determined manner. 
     
     
         4 . The calender according to  claim 2 , wherein the database and the control means are connectable to each other wirelessly or via a computer network. 
     
     
         5 . The calender according to  claim 1 , wherein the at least one first temperature sensor comprises a thermocouple arranged against the outer periphery of the roller. 
     
     
         6 . The calender according to  claim 1 , wherein the at least one first temperature sensor comprises an infrared sensor arranged at a distance from the roller. 
     
     
         7 . The calender according to  claim 1 , comprising a plurality of first temperature sensors which are disposed distributedly over the width of the roller for measuring the temperature of an outer periphery of the roller distributed over the width of the roller. 
     
     
         8 . The calender according to  claim 1 , further comprising flow influencing means for initiating and/or influencing a flow of the fluid in the internal space, wherein further control means are configured to control the flow influencing means and thereby the flow of the fluid in the internal space in freely settable manner. 
     
     
         9 . A method for controlling a calender according to  claim 1 , which method comprises the following steps of:
 a) measuring the outer periphery temperature of the roller;   b) controlling the heating means and/or the belt pressure and/or the contact time by means of the one or more control means on the basis of the outer periphery temperature measured in step a); and   c) measuring the fluid temperature, wherein in step b) the control means also control the heating means and/or the belt pressure and/or the contact time on the basis of the fluid temperature measured in step c).   
     
     
         10 . The method according to  claim 9 , further comprising, before step b) the step of:
 setting or determining a target temperature for the outer periphery of the roller;   wherein in step b) the one or more control means control the heating means and/or the belt pressure and/or the contact time for the purpose of heating the outer periphery of the roller and/or keeping the roller at the target temperature up to at least roughly the desired target temperature.   
     
     
         11 . The method according to  claim 9 , comprising controlling a calender, the calender comprising:
 a rotatable roller, which roller is hollow and thereby defines an internal space which is configured to be filled at least partially with a heatable fluid;   a belt, co-acting with the roller, with a determined belt pressure, wherein at least one material for feeding through the calender is situated between the roller and the belt for a determined contact time during throughfeed through the calender;   heating means for heating the fluid and/or the roller, which heating means are disposed in the internal space;   one or more control means for controlling the heating means and/or the belt pressure and/or the contact time,   at least one first temperature sensor for measuring the temperature of an outer periphery of the roller, and   at least one second temperature sensor for measuring the temperature of the fluid, wherein the one or more control means are configured to control the heating means and/or the belt pressure and/or the contact time on the basis of the measured outer periphery temperature and the measured fluid temperature;   a database in which at least one of the following data is stored periodically:
 the measured outer periphery temperature of the roller; 
 a or the measured fluid temperature; 
 the contact time; 
 the belt pressure; 
 a power of the heating means; 
 a number of revolutions of the roller since the start of a calendering process; 
 at least one property of the at least one material being fed through the calender; 
 at least one property of a transfer paper optionally being fed through the calender; 
 an ambient temperature; 
 an air humidity; 
 which calender is used; 
 a power of drive means of the calender; and 
 at least one property of a belt of the calender, 
   
       and wherein the control means are further configured to control the heating means and/or the belt pressure and/or the contact time on the basis of at least one of the data contained in the database
 wherein in step b) the control means is configured to control the heating means and/or the belt pressure and/or the contact time on the basis of at least one of the data stored in the database. 
 
     
     
         12 . The method according to  claim 11 , comprising controlling a calender, the calender comprising
 a rotatable roller, which roller is hollow and thereby defines an internal space which is configured to be filled at least partially with a heatable fluid;   a belt, co-acting with the roller, with a determined belt pressure, wherein at least one material for feeding through the calender is situated between the roller and the belt for a determined contact time during throughfeed through the calender;   heating means for heating the fluid and/or the roller, which heating means are disposed in the internal space;   one or more control means for controlling the heating means and/or the belt pressure and/or the contact time,   at least one first temperature sensor for measuring the temperature of an outer periphery of the roller, and   at least one second temperature sensor for measuring the temperature of the fluid, wherein the one or more control means are configured to control the heating means and/or the belt pressure and/or the contact time on the basis of the measured outer periphery temperature and the measured fluid temperature;   a database in which at least one of the following data is stored periodically:
 the measured outer periphery temperature of the roller; 
 a or the measured fluid temperature; 
 the contact time; 
 the belt pressure; 
 a power of the heating means; 
 a number of revolutions of the roller since the start of a calendering process; 
 at least one property of the at least one material being fed through the calender; 
 at least one property of a transfer paper optionally being fed through the calender; 
 an ambient temperature; 
 an air humidity; 
 which calender is used; 
 a power of drive means of the calender; and 
 at least one property of a belt of the calender, 
   wherein the control means are configured to determine on the basis of at least periodically measured outer periphery temperatures and periodically measured fluid temperatures of a plurality of prior calendering processes and on the basis of at least the at least one property of the same material how the heating means and/or the belt pressure and/or the contact time must be set in order to obtain a desired outer periphery temperature in the current calendering process, and to control the heating means and/or the belt pressure and/or the contact time in the determined manner;   which method further comprising the step e) of determining by means of the control means and on the basis of at least periodically measured outer periphery temperatures and periodically measured fluid temperatures of a plurality of prior calendering processes and on the basis of at least the at least one property of the same material how the heating means and/or the belt pressure and/or the contact time must be set in order to obtain a desired outer periphery temperature in the current calendering process, and of controlling the heating means and/or the belt pressure and/or the contact time in the determined manner.   
     
     
         13 . The method according to  claim 9 , comprising controlling a calender, the calender comprising:
 a rotatable roller, which roller is hollow and thereby defines an internal space which is configured to be filled at least partially with a heatable fluid;   a belt, co-acting with the roller, with a determined belt pressure, wherein at least one material for feeding through the calender is situated between the roller and the belt for a determined contact time during throughfeed through the calender;   heating means for heating the fluid and/or the roller, which heating means are disposed in the internal space;   one or more control means for controlling the heating means and/or the belt pressure and/or the contact time,   at least one first temperature sensor for measuring the temperature of an outer periphery of the roller,   at least one second temperature sensor for measuring the temperature of the fluid, wherein the one or more control means are configured to control the heating means and/or the belt pressure and/or the contact time on the basis of the measured outer periphery temperature and the measured fluid temperature; and   flow influencing means for initiating and/or influencing a flow of the fluid in the internal space, wherein further control means are configured to control the flow influencing means and thereby the flow of the fluid in the internal space in freely settable manner;   which method further comprises the following steps of:   f) setting or determining a setting of the flow influencing means;   g) controlling the flow influencing means, and thereby the flow of the fluid in the internal space, by means of the control means so as to achieve the setting set or determined in step f).   
     
     
         14 . The method according to  claim 10 , wherein at least steps a) and b) are performed iteratively. 
     
     
         15 . A set with a plurality of calenders according to  claim 1 , wherein the control means of at least one of the calenders are configured to control the heating means and/or the belt pressure and/or the contact time of that one calender on the basis of periodically registered data of calendering processes performed with the calenders of the set.