System to counter contact oscillation in paired rollers processing a paper web has force units and tensioners within the rollers to modify their inner tension under control according to sensor measurements

摘要

To prevent contact oscillation in rotating rollers (12,14) forming a gap (N) between them with a web (16) passing through it, in a papermaking or paper finishing machine (18), the resonance frequency is modified at the rollers (12,14) and their bearings by an alteration to the inner tension of a least one of the rollers (12,14). The inner tension of at least one roller (12,14) is adjusted by at least one unit (26,28;34,38) which applies a force with a system using hydraulics and/or pneumatics and/or hydropneumatics and/or electromagnetic and/or electrochemical means. At least one force unit (26) is a pressure hose and/or pressure bellows and/or a pressure chamber. At least one force unit (28,38) is a piston/cylinder assembly. At least one force unit (34) is a threaded adjustment spindle. The inner tension of at least one roller (12,14) is changed by at least one tensioner (30,32,40) as springs and pref. coil springs, with at least one spring (32) which can be adjusted to set the pretension. At least one force unit (26,28;34) and/or at least one tensioner (30,32) has one end at the inner circumference surface (12b) of the roller (12), with the other end at a yoke (22) at the roller axis (A). At least one force unit (38) and/or at least one tensioner (40) has both ends at the inner circumference surface (14b) of the other roller (14). A number of force units (26,28;34,38) and/or tensioners (30,32;40) are deployed equidistantly pref. over the inner circumference surfaces (12b,14b) of the rollers (12,14). The inner tension of the rollers (12,14) is adjusted while they are running in the machine (18), and the adjustments are reversible or durable. The adjustments are made by a control (46) according to signals from at least one oscillation sensor (42,44). An Independent claim is included for a papermaking or paper finishing roller assembly, such as for spreading a coating medium (20) on to the web (16) surface(s), where at least one roller (12,14) has a system (26,28;30,32,34,38,40) to vary the inner roller tension. Preferred Features: A control (46) gives an automatic alteration to the setting of at least one force unit (26,28;38) and/or a tensioner (34) to modify the pretension of at least one tensioner (32), pref. according to the measurements of at least one oscillation sensor (42,44).