A method for changing the natural frequency of a nip roll construction in a paper or board machine. In the method, the bearing elasticity of a hydrostatic bearing element (10, 20, 30, 40) of at least one roll (1) in the nip roll construction is changed, in which connection the natural frequency of the roll (1) is also changed. The device that carries out the method comprises a pressure medium accumulator (39), which has been connected to the pressure side of a loading element (13, 23, 33) of at least one hydrostatic bearing element (10, 20, 30).

Method and device for changing the natural frequency of a nip roll construction in a paper or board machine

The present invention relates to a support arrangement (10) of a roll of a fibrous-web machine, which comprises a first frame part (12) in which the roll (20) of the fibrous-web machine is supportable from its end when in use and a second frame part (22) in which the first frame part (12) is fastened by means of an elastic fastening. The arrangement comprises a motion direction control arrangement (34) for controlling the direction of the motion allowed by the elastic fastening in a way determined by the direction control arrangement (34). (Fig. 1)

Support arrangement of roll in fibrous-web machine

The method involves changing a resonance frequency of a cylinder (01,02) by inserting or diverting of matters (12,27) into the interior of the cylinder or from the interior of the cylinder. The matter is a liquid. The liquid used, is water and oil, which are cooling agent and a lubricant. The matters also uses flowing solid, which are metal balls. The filling condition of the cylinder changes depending on the rotation speed of the cylinder. An independent claim is also included for a device for reducing vibrations of a rotary cylinder of a printing machine.

Method for reducing vibrations of rotary cylinder of printing machine, involves changing resonance frequency of cylinder by inserting or diverting of matters into interior of cylinder or from interior of cylinder

An arrangement of attenuating the vibration in a roll assembly of a fiber web machine, in which assembly the roll (10) being rotatably suspended at its end on bearings in bearing housings (13a, 13b), and the bearing housings being supported on the frame or the foundation of the machine via viscoelastic intermediate piece or pieces (21a, 21b). According to the invention the loss factor of the intermediate piece is greater than 0.1 at the normal operating conditions of the roll at a frequency range, which is ±10 % calculated from the lowest bending eigenfrequency of the roll, and in the each end of the rolthe spring constant of the total influence of the intermediate piece or pieces is in the range of 0.04 GN/m - lGN/m.

Arrangement for attenuating vibration of a roll assembly

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. The pressure in and the volume of the work pressure space (16) are kept invariable, and the volumes of the counter-pressure spaces (18, 20) are varied, in which connection the cylinder (11) moves on the piston rods (14, 15), and the rigidity of the loading cylinder can be varied.

The invention relates to a method and an installation in the roll operation of a paper machine. In order to prevent vibration of the roll in the critical speed ranges, the position of the critical speed ranges u KR, u 1/2KR of the roll is adjusted whilst the roll is running.

Uuttana Kyoesti

Papers

Method in the roll operation of a paper machine and installation for the method

Process for use in the reconditioning of a roller belonging to a papermaking machine