INTERNAL WALL TEMPERATURE DIFFERENCE DETECTING DEVICE FOR FURNACE BODY

摘要

PURPOSE:To simplify the structure and to secure abnormality detection by arranging detection lines which have electric resistance characteristics around the periphery of the internal wall of the furnace body and detecting the generation of temperature differences among respective parts of the internal wall from differences among the resistance values of the detection lines. CONSTITUTION:Variable resistances RH connected in series with the detection lines 27(A-d) are operated to make an adjustment so that a bridge circuit is balanced. Then an AC current is supplied to an induction coil 22 and when the internal wall 25 nearby the detection line 27(A1) raises in temperature extremely high, the resistance value of the detection line 27(A) consisting of the detection lines 27(A1-A4) increases extremely as compared with other detection lines 27(B-D), so that the local heating phenomenon of the internal wall 25 is detected in the form of the value of the ammeter of a Wheatstone bridge. Similarly, even if the resistance value of some of the detection lines 27(A2-A4), (B1-B4), (C1-C4), and (D1-D4) increases owing to a temperature raise, that is easily detected and even the breaking of a detection line 27 can be detected.