Patent ID: 6270628
Filing Date: 2001-08-07
Classification: D21G,G01H,Y10S

Abstract:
A method for detecting contamination and/or damage in a face (11,12') of a roll running through a nip (N) or nips in a calender, comprising the steps of:detecting rotational vibrations in said calender caused by contamination or damage to said face during operation or construction of the machine by means of at least first and second detectors (20,21,25) structured and arranged on at least one of said face and a bearing housing supporting said calender roll, said at least a first detector being adapted to measure said vibrations and generate a first time based vibration signal f.sub.a (t) and said at least a second detector being adapted to measure said vibrations and generate a second time based vibration signal f.sub.b (t), anddetermining the location of said damage and/or contamination (M:M.sub.1,M.sub.2) on said face to be monitored (11, 12') based on said first time based vibration signal f.sub.a (t) and said second time based vibration signal f.sub.b (t).