Multiple groups of sensors are circumferentially spaced apart at each cross-directional position along a sensing roll of a nip press to measure and cancel or nearly cancel the effects of rotational variability which may be acting on the sensing roll. The strategically-placed sensors are designed to measure the pressure being placed against the web that is being advanced through the nip press. The average of the measurements of multiple sensors spaced circumferential apart provides a good cancellation of any rotational variability that might be found at a cross-directional position on the sensing roll. In this manner, a more true measurement of the nip pressure profile can be obtained and better adjustments made to reduce nip pressure profile variability. In addition, the nip variability profile may be used as a predictor of cover or bearing failures, resonant frequencies and other roll anomalies.

Multiple groups of sensors are circumferentially spaced apart at each cross-directional position along a sensing roll of a nip press to measure and cancel or nearly cancel the effects of rotational variability which may be acting on the sensing roll. The strategically-placed sensors are designed to measure the pressure being placed against the web that is being advanced through the nip press. The average of the measurements of multiple sensors spaced circumferential apart provides a good cancellation of any rotational variability that might be found at a cross-directional position on the sensing roll. In this manner, a more true measurement of the nip pressure profile can be obtained and better adjustments made to reduce nip pressure profile variability. In addition, the nip variability profile may be used as a predictor of cover or bearing failures, resonant frequencies and other roll anomalies.

A sensor signal is generated from a plurality of sensors located on a sensing roll, wherein each signal is generated when each sensor enters a first nip between the sensing roll and a rotating component during each rotation of the sensing roll. A rotating applicator rod forms forming a second nip with the sensing roll such that each sensor enters the second nip during each rotation of the sensing roll. A periodically occurring starting reference is generated associated with each rotation of the applicator rod and the signal generated by each sensor is received so that a particular one of the sensors which generated the signal is determined and one of a plurality of tracking segments is identified. The signal is stored to associate the sensor signal with the identified one tracking segment.

A sensor signal is generated from a plurality of sensors located on a sensing roll, wherein each signal is generated when each sensor enters a first nip between the sensing roll and a rotating component during each rotation of the sensing roll. A rotating applicator rod forms forming a second nip with the sensing roll such that each sensor enters the second nip during each rotation of the sensing roll. A periodically occurring starting reference is generated associated with each rotation of the applicator rod and the signal generated by each sensor is received so that a particular one of the sensors which generated the signal is determined and one of a plurality of tracking segments is identified. The signal is stored to associate the sensor signal with the identified one tracking segment.

The invention relates to an extended nip roll 1 for use in a nip N through which a fibrous web W is to be passed. The roll has two axial ends 3, 4 and comprises a support beam 5 having an axial extension between the axial ends 3, 4 of the extended nip roll and a press body 6 with an axial extension and which press body 6 is substantially parallel with the support beam 5 as well as means 7 supported by the support beam 5 for causing the press body to move or expand radially outwards towards a counter roll 2 to form a nip N. The inventive roll also comprises a tubular flexible jacket 8 with two axial ends 12, 13, the tubular flexible jacket 8 forming a loop around the press body 6 and the support beam 5. At each end of the extended nip roll 1, there is an end wall 9, 10 which is rotatably journalled to allow each end wall 9, 10 to rotate about the support beam 5. Each end wall 9, 10 being attached to an axial end 12, 13 of the tubular flexible jacket 8 such that the end walls 9, 10 and the tubular flexible jacket 8 form together an enclosed space 14. On the support beam 5, there is at least one support element 15 for the tubular flexible jacket 8 which support element 15 is arranged to support a part of the tubular flexible jacket 8 at a location spaced away from the press body 6. According to the invention, the at least one support element 15 is arranged to be movable in a circumferential direction such that it can be moved to different positions along the circumference of the tubular flexible jacket 8.

A sensor signal is generated from a plurality of sensors located on a sensing roll, wherein each signal is generated when each sensor enters a first nip between the sensing roll and a rotating component during each rotation of the sensing roll. A rotating applicator rod forms forming a second nip with the sensing roll such that each sensor enters the second nip during each rotation of the sensing roll. A periodically occurring starting reference is generated associated with each rotation of the applicator rod and the signal generated by each sensor is received so that a particular one of the sensors which generated the signal is determined and one of a plurality of tracking segments is identified. The signal is stored to associate the sensor signal with the identified one tracking segment.

A sensor signal is generated from a plurality of sensors located on a sensing roll, wherein each signal is generated when each sensor enters a first nip between the sensing roll and a rotating component during each rotation of the sensing roll. A rotating applicator rod forms forming a second nip with the sensing roll such that each sensor enters the second nip during each rotation of the sensing roll. A periodically occurring starting reference is generated associated with each rotation of the applicator rod and the signal generated by each sensor is received so that a particular one of the sensors which generated the signal is determined and one of a plurality of tracking segments is identified. The signal is stored to associate the sensor signal with the identified one tracking segment.

A press arrangement for a machine for producing and/or processing a fibrous web, in particular a paper, board or tissue web. The arrangement has at least a central roll and a first and a second mating pressing unit. The first mating pressing unit forms a first press nip with the central roll, and the second mating pressing unit forms a second press nip with the central roll. The central roll has a plurality of pressure sensors embedded in the central roll and arranged beside one another in the cross-machine direction, by way of which the pressure profile in the cross-machine direction can be determined in the first and in the second press nip. There is also disclosed a method for operating such a press arrangement.

A press arrangement for a machine for producing and/or processing a fibrous web, in particular a paper, board or tissue web. The arrangement has at least a central roll and a first and a second mating pressing unit. The first mating pressing unit forms a first press nip with the central roll, and the second mating pressing unit forms a second press nip with the central roll. The central roll has a plurality of pressure sensors embedded in the central roll and arranged beside one another in the cross-machine direction, by way of which the pressure profile in the cross-machine direction can be determined in the first and in the second press nip. There is also disclosed a method for operating such a press arrangement.

Multiple groups of sensors are circumferentially spaced apart at each cross-directional position along a sensing roll of a nip press to measure and cancel or nearly cancel the effects of rotational variability which may be acting on the sensing roll. The strategically-placed sensors are designed to measure the pressure being placed against the web that is being advanced through the nip press. The average of the measurements of multiple sensors spaced circumferential apart provides a good cancellation of any rotational variability that might be found at a cross-directional position on the sensing roll. In this manner, a more true measurement of the nip pressure profile can be obtained and better adjustments made to reduce nip pressure profile variability. In addition, the nip variability profile may be used as a predictor of cover or bearing failures, resonant frequencies and other roll anomalies.