SYSTEM FOR DETECTING PRIMARY NONUNIFORM THICKNESS, METHOD FOR DETECTING PRIMARY NONUNIFORM THICKNESS, AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To early and accurately detect primary nonuniform thickness occurring in a hollow element tube.SOLUTION: Information which indicates a relationship between a primary nonuniform thickness rate and an eccentric amount of a plug 12 and a core grid 13 is prestored. An acceleration sensor 15 is located in at least one of the plug 12 and the core grid 13 so as to rotate coaxially with the plug 12 and the core grid 13, the eccentric amount of the plug 12 and the core grid 13 is derived by use of an acceleration measured by the acceleration sensor 15. Then, the primary nonuniform thickness rate corresponding the eccentric amount of the plug 12 and the core grid 13 is derived from the above relationship, and when the primary nonuniform thickness rate exceeds a threshold, information which indicates that is output.SELECTED DRAWING: Figure 1