Calender arrangement

A vertical calender apparatus for treating a paper web, said apparatus comprising:

• a controllable-deflection top roll;
• a controllable-deflection bottom roll;
• a plurality of auxiliary drives;
• a plurality of guide roll drives;
• a plurality of intermediate guide rolls arranged between the top roll and the bottom roll to define a calender stack, two of the plurality of intermediate guide rolls are heatable hard rolls and a central one of the plurality of intermediate guide rolls is provided with a resilient cover, each intermediate roll coupled to one of the auxiliary drives for in-line operation to pull in the paper web during operation;
• a plurality of guide rolls arranged adjacent to the calender stack, each guide roll coupled to one of the guide roll drives;
• a first main power drive to transmit torques to all the rolls frictionally, the first main power drive connected to the top roll via a first gear mechanism;
• a second main power drive connected to the bottom roll via a second gear mechanism, wherein the first and second gear mechanism have the same construction such that equal torques is applied to the top and bottom rolls using the first and second main power drives at substantially the same power;
• and
• a control unit for applying substantially the same power to the first and second main power drives to drive the top and bottom rolls.