Method, system and a computer program product for condition monitoring of a fiber web or paper finishing machine

1. A method for displaying a pattern signifying vibration in a fiber web machine or a paper finishing machine, the method employing at least one roll mounted for rotation and equipped with a sensor assembly that measures a cross-directional profile of force and/or pressure between the roll and a counter-pair when engaged in a relation where the roll is rotated against the counter-pair, comprising the steps of:

recording with the sensor assembly at least one cross-directional reference profile of force and/or pressure, between the roll and the counter-pair as the roll rotates against the counter-pair, wherein the reference profile is obtained while the cross-directional profile is substantially non-varying, or is a computed average of the cross-directional profile over a time period which forms a substantial non-varying value;

comparing a measurement signal from the sensor assembly comprising at least a cross-directional profile of force and/or pressure between the roll and the counter-pair when engaged in a relation where the roll is rotated against the counter-pair with the cross-directional reference profile, wherein the cross-directional profile and the cross-directional reference profile are with respect to the same roll and counter-pair which are engaged in the same relation; and

visually displaying the measurement signal compared to the cross-directional reference profile over time, to show vibrational loading experienced by the sensor assembly for condition monitoring.

2. The method of claim 1 wherein the step of comparing the measurement signal from the sensor assembly to the cross-directional reference profile is by forming a differential profile between the cross-directional profile and the cross-directional reference profile.

3. The method of claim 2 wherein the step of visually displaying includes display of a time series of a plurality of measurement signals compared to the cross-directional reference profile, and wherein the step of visually displaying further comprises displaying a graphic representation of the cross-directional profile at different points in time, to display time varying loading in the cross-direction.

4. The method of claim 1 wherein the step of visually displaying the measurement signal compared to the cross-directional reference profile, to show vibrational loading experienced by the sensor assembly, is in a video format representation formed of the cross-directional profile or the differential profile at a multiplicity of sequential points in time.

5. The method of claim 1 wherein information from the measurement signal from the sensor assembly is analysis regarding the source, level, and at least one of frequency and phase of variation.

6. The method of claim 1 further comprising determining the frequency of variation from the measurement signal with a Fast Fourier Transform (FFT) method.

7. A method for displaying a pattern signifying vibration in a fiber web machine or a paper finishing machine, the method employing at least one machine element mounted for rotation and equipped with a sensor assembly that measures a cross-directional profile of force and/or pressure between the machine element and a counter-pair when engaged in a relation where the machine element is rotated against the counter-pair, comprising the steps of:

recording with the sensor assembly at least one cross-directional reference profile of force and/or pressure, between the machine element and the counter-pair as the machine element rotates against the counter-pair, wherein the reference profile is obtained while the cross-directional profile is substantially non-varying, or is a computed average of the cross-directional profile over a time period which forms a substantial non-varying value;

comparing a measurement signal from the sensor assembly that measures a plurality of cross-directional profiles over time to the cross-directional reference profile, wherein the cross-directional profiles over time and the cross-directional reference profile are with respect to the same machine element and counter-pair which are engaged in the same relation; and

continuously displaying with respect to time visually, a time series of the measurement signal compared to the cross-directional reference profile, to show time varying changes arrayed in the cross-machine direction which correlate to vibrational loading experienced by the sensor assembly.

8. The method of claim 7 wherein the counter-pair of the machine element equipped with a sensor assembly is another rotating machine element or a roll forming from a fiber web produced in a fiber web machine, with which the machine element equipped with said sensor assembly forms a roll nip or a reeling nip.

9. The method of claim 7 wherein the cross-directional profile formed from the measurement signal and representing force or pressure generated between the machine element and its counter-pair and the reference profile are analyzed by comparing them with each other for detecting periodic variation extreme values of force or pressure appearing in the cross-directional profile.

10. The method of claim 7 wherein the rotating machine element includes a shell, at least one cover layer disposed on the shell, and a sensor assembly installed in a spiral fashion under at least one or between at least two of said cover layers.

11. A system for displaying a pattern signifying vibration in a fiber web machine or a paper finishing machine, the system comprising:

at least one machine element mounted for rotation and engaging a counter-pair, the machine element being equipped with a sensor assembly connected to form an output signal source of a cross-directional profile of force and/or pressure between the machine element and a counter-pair;

a data memory connected to the output signal source to record a cross-directional reference profile while the cross-directional profile is substantially non-varying, or receiving from a computer an average of the cross-directional profile over a time period which forms a substantial non-varying value;

a computer connected to the output signal source and having an images feed output which supplies a plurality of time sequenced display outputs of the cross-directional profile of force and/or pressure between the machine element and the counter-pair, from which the cross-directional reference profile, after retrieval from the data memory is subtracted;

wherein the cross-directional profiles over time and the cross-directional reference profile are with respect to the same machine element and counter-pair which are engaged in the same relation; and

an operator display panel connected to the images feed output to over time display in one direction the cross-directional profiles and in a transverse direction each of the plurality of time sequenced display outputs aligned one after another to show time varying changes in the crossmachine direction which correlate to vibrational loading experienced by the sensor assembly.