METHOD AND ARRANGEMENT FOR CONTROLLING A SCREENING ROOM

摘要

The present invention relates to a method and arrangement for regulating a screening process and/or a screen by means of an automatic system during screening of fiber suspension in a screening apparatus having a screen drum for dividing the fiber suspension into reject and accept and a rotor. The driving power for the rotor or screen drum is an electric motor, the rotational speed of which is regulated by means of a frequency converter based on pulp, machine and running parameters. The pulp and/or running parameters of the screen are measured and for each screen is determined a functional dependence of an operational value on the rotational speed with respect to the pulp parameter and/or running parameter based on the measurement results, when the operational value is motor input power, torque, accept flow pressure, reject flow pressure, pressure difference, reject and/or accept consistency. The rotational speed is adjusted anticipatorily according to these dependences by means of the automatic system so that the screen operates within an optimal operational value range that is determined based on said dependence.