Abstract: A method and apparatus for damping vibration in a paper machine. The apparatus having a dynamic damper which includes a weight suspended by a spring. The spring constant of the spring is changed by means of a control device in order to tune the natural frequency of the dynamic damper. The dynamic damper is tuned to a frequency that is substantially equal to a multiple of the rotational frequency of the roll in the paper machine that is being damped.

Abstract: The invention concerns a method and a device for changing the natural frequency of a nip roll construction in a paper or board machine so that the rigidity of one or several loading elements, for example loading cylinder or loading beam, in the nip roll construction is varied. The loading cylinder with adjustable rigidity in accordance with the invention comprises a cylinder (11), into which two pistons (12, 13) have been fitted. The pistons (12, 13) have been attached each of them to a piston rod (14, 15) of its own, which piston rods have been passed through the end walls (11a, 11b) of the cylinder (11). Thus, in the cylinder (11), between the pistons (12, 13), a work pressure space (16) is formed, and at the opposite sides of the pistons (12, 13) counter-pressure spaces (18, 20) are formed.

Abstract: An apparatus for reducing or preventing vibrations of a roll set of a paper making apparatus, wherein the roll set comprises at least two rolls of which at least one is a soft roll coated with a compressible coating and comprising a temperature control system. The natural vibrational frequency of the roll set is changed during the operation of the apparatus by changing the temperature of the coating of the at least one soft roll. The changing of the natural frequency prevents resonance on a natural frequency of the roll set.

Abstract: An applicator device for applying a coating agent onto a moving base, such as a paper or board web, onto the face of a film press roll, or equivalent, and a method for correcting for distortions arising from thermal strains in such an applicator device. The applicator device includes an applicator beam arranged in a direction transverse to a running direction of the moving base, a coating-agent feed pipe arranged in the transverse direction and mounted on the applicator beam, and coating members mounted on the applicator beam for applying a coating onto the moving base and spreading and smoothing the coating agent onto the moving base. The coating-agent feed pipe and the coating members are constructed as a single unit. The device also includes mounting members for mounting the single unit of the coating-agent feed pipe and the coating members on the applicator beam.

Abstract: A method for reducing or preventing vibrations of a roll set of a paper making apparatus, wherein the roll set comprises at least two rolls of which at least one is a soft roll coated with a compressible coating and comprising a temperature control system. The natural vibrational frequency of the roll set is changed during the operation of the apparatus by changing the temperature of the coating of at least one soft roll. The changing of the natural frequency prevents resonance on a natural frequency of the roll set.