HEAT-TREATING FURNACE

PURPOSE:To effectively control the fluctuations of the tension of a band steel in the heat-treating furnace for the band steel due to the disturbance such as the movement of a loop car by providing a mechanical resonance controlling device in the speed control system for a bridle roll or helper roll in the furnace. CONSTITUTION:A band steel such as magnetic steel sheet is continuously traveled in the heat-treating furnace and annealed. In this case, the tension of the band steel 1 in the furnace is detected by a tension meter 3, the tension detection signal is compared with a tension reference signal from a reference tension generator 6, and the deviation signal is inputted to a tension controller 7. A speed correcting signal is outputted from the controller 7 based on the deviation signal and added to the speed reference signal from a reference speed generator 8, and the deviation between the outputs and the feedback signal from a speed detector 5 is obtained. The deviation signal is inputted to a speed controller 9, and a current command signal from the controller is inputted to a current controller 10 to control the speed of a motor 4 for driving the bridle roll 2. The mechanical resonance controlling device 11 is provided to the speed control system IV for the bridle roll 2, and the fluctuations of the tension of the band steel 1 in the furnace is effectively controlled.