System in a press section of a paper machine for monitoring and control

Abstract

System in a press section of a paper machine for monitoring and control of the running of the press felts (10,20,30). The press felts (10,20,30) are guided by means of rolls (13,14,15; 23,24,25; 33,34, 35), whose axial directions are altered by means of an actuator (18a, 18b) so as to control the running of the press felts (10,20,30). The system includes detector devices (16,26,36), by whose means the alignment stripe (K) on the felt or felts (10,20,30) is detected, as well as oscillation detectors (17,27,37), by whose means oscillations of the press rolls (10, 20,30) are detected. Into the computer part (50) included in the system, the monitoring signals (a,b) are fed from said detectors (16,26,36, 17,27,37). The computer (50) analyzes the detector data in order to detect any felt-induced oscillations. By the intermediate of a control system (40), the computer (50) regulates the actuators (18a, 18b) of the guide rolls that guide the running of the felts (10,20,30) so that, when the oscillation levels of the press rolls rise beyond certain limits, the direction of the guide roll of the felt (10;20;30) that causes the oscillation is turned until an acceptable level of oscillation and/or a level of oscillation as low as possible is found.