METHOD AND DEVICE FOR ELECTROMAGNETIC HEATING OF A ROLL, IN PARTICULAR OF A CALENDER ROLL, USED IN THE MANUFACTURE OF PAPER OR OF SOME OTHER WEB-FORMED PRODUCT

摘要

in the process of electromagnetic heating of a cylinder, in particular to a cylinder shape for use in the manufacture of paper or other materials in the form of a strip.a variable magnetic flux is directed on the outer envelope (10) of the cylinder, without contact, by means of a magnetic roller device (20) through entrefers (40a, 40b)40 (c)), the magnetic flux inducing eddy currents in the outer envelope (10) of the cylinder.which the eddy currents generate heat due to the resistance of the outer envelope (10) of the cylinder.this magnetic flux is applied to the outer envelope (10) of the cylinder with the aid of a magnetic roller device (20) which includes a number of nodes (201).20) placed side by side.the value (delta) of the air gap between the core and the face (10) of the outer envelope (10) of the cylinder and / or magnetization currents are adjusted to control the distribution ofthe effect of stretching in the axial direction (k - (k) of the cylinder.in this heating, are used as the frequency (f) of the power frequency magnetization nuclei so high that a sufficiently deep penetration (a) of the heating effect is obtained.in addition, it is proposed a device for cylinder whose nuclei (201...20) the magnetization device (20) are each arranged so that their positions in the radial plane of the cylinder (10) can be adjusted in order to regulate or partiellemes the effect of heating in the axial direction (k - (k) of the cylinder. the device includes a power supply means (33, 34, 35, 36, 37) through which the coils (301).30n) are powered by an alternating current of an appropriate frequency is constant or variable (f).