ESTIMATION METHOD OF BREAKING OF ROLL SHAFT AND DETECTOR FOR DETECTING CRACK LENGTH OF ROLL SHAFT

摘要

PROBLEM TO BE SOLVED: To provide an estimation method of the breaking of a roll shaft excellent in general-purpose properties and estimating and detecting the life of the roll shaft in an extremely easy manner at a low cost to prevent the breaking accident of the roll shaft, and a detector for detecting the crack length of the roll shaft. SOLUTION: An AC magnetic field is applied to the roll shaft 3b in a papermaking machine or the like by an electromagnetic sensor 1 and a reaction magnetic flux is produced in the roll shaft 3b. The reaction magnetic flux measuring data value correlated with the crack length produced in the roll shaft 3b is detected by the electromagnetic sensor 1 and the allowable crack length reaching breaking is operated from preliminarily inputted measuring roll data, roll operation data, the crack propagation speed of the material of the roll shaft 3b or the like and compared with the reaction magnetic flux measuring data value to judge whether the roll shaft 3b is in a state of reaching breaking. COPYRIGHT: (C)2005,JPO&NCIPI