Load monitoring method and load monitoring apparatus for kneading apparatus

摘要

In an extruder or a kneader, load (torque T) values on an input shaft portion of a screw shaft are detected by a load detector installed on the input shaft portion, then an overload condition is determined from a load mean value (Ta) and a load amplitude value (Tw) of the detected load values, and the issuance of an “abnormal” alarm and/or the stop of rotation of the screw shaft are (is) performed when an overload duration time (to) of maintaining the overload condition exceeds a set time (ts). In this way the screw shaft is protected from fatigue fracture caused by application thereto of such a load as does not exceed a designed mechanical strength but causes fatigue fracture.