System to counter contact oscillation in paired rollers processing a paper or cardboard web has systems to vary their mass/mass distribution and position and speed under control according to sensor measurements

摘要

To counter contact oscillation between rollers (12,14) where a web (16) moves between them, in a papermaking or cardboard prodn. machine (18), the resonance frequency is varied by changing (22-30) the mass and/or mass distribution in at least one (14) of the two rollers and/or adjusting (40,42) the force transfer ratios between the mantle surfaces (12a,14a) of both rollers (12,14) At least one roller (14) has at least one hollow zone (22,30) which can be filled or emptied selectively with a fluid medium (24). The fluid medium (24) can be transferred between two hollow zones (22,30) in the roller (14), and can be transferred between an external supply point (26) and the roller hollow zone (22). The relative positions of the rollers (12,14) can be adjusted (40), while the set dimensions (d) of the gap between them are unchanged. The rotary speed of at least one roller (12,14) can be varied (42). The roller settings can be changed while the machine is working, and the alterations are reversible or durable. The adjustments to set the roller resonance frequency are made according to the measurements of at least one oscillation sensor (44). An Independent claim is included for a roller assembly where two rollers (12,14) form a gap (N) between them for a web (16) to pass through, where at least one roller (14) has a system (22,26,28,30,32) to alter the mass and/or mass distribution and/or a mechanism (40,42) to vary the force transmission ratio between the mantle surfaces (12a,14a) of the two rollers (12,14). Preferred Features: The roller hollow zones (22,30) are cylindrical, which can be filled and emptied selectively with a fluid medium (24). A control (46) determines the working of the setting units (28,32,34,40,42) to vary the roller resonance frequency according to the measurement of at least one oscillation sensor (44). At least one acceleration sensor (44') acts as an oscillation sensor at a bearing or bearing housing for at least one of the two rollers.