| 摘要 |
PURPOSE:To set the operational temperature of a safety device accurately, by arranging a safety device which opens circuit when a heating body is heated over a predetermined temperature and a branch circuit which is interlocked with the safety device to open the circuit on the current path of the heating body to be temperature controlled. CONSTITUTION:A heater 2 is arranged in a heating roll 1 and connected through a safety device 4 and a solidstate relay with a power source 3. A temperature controller 9 is constituted such that outputs from a temperature sensor 6 fixed to a roll 1 and a relay 8 are fed to an electric circuitboard 7. A branch circuit 10 is arranged in parallel with the safety device 4, and a fuse 5 interlocked with the safety device 4 to open the circuit is provided. The circuitboard 7 normally opens/closes the relay 8 based on an output from the temperature sensor 6 to maintain the temperature at a predetermined level so as to branch the heating current Ir into currents IA and IS. In case of abnormal temperature, the safety device 4 and the fuse 5 operate to bring the current Ir to zero. Consequently, the current IA flowing through the safety device 4 can be set lower than the heating current Ir and the operating point of the safety device can be set precisely. |
